JP7694368B2 - Control device for internal combustion engine system - Google Patents

Description

The present invention relates to a control device for an internal combustion engine system that adjusts the amount of fuel injected into the internal combustion engine using air-fuel ratio feedback control.

For example, in a forklift equipped with an LPG engine (natural gas engine), the amount of fuel is adjusted to be close to the theoretical air-fuel ratio as a measure against exhaust gas, and the exhaust gas is purified using a three-way catalyst provided in the exhaust path. In order to adjust the amount of fuel to be close to the theoretical air-fuel ratio, an air-fuel ratio related information detection device ( _O2 sensor or A/F sensor) is provided in the exhaust path. In addition, an injector is arranged in the intake path, and the amount of fuel from the injector is adjusted by air-fuel ratio feedback control based on the detection signal (air-fuel ratio related information) from the air-fuel ratio related information detection device ( _O2 sensor or A/F sensor) to achieve a targeted air-fuel ratio.

In the case of an LPG engine, the amount of fuel supplied by the injector alone is insufficient, so a fuel mixer that mixes fuel with the intake air is placed in the intake path in addition to the injector. The fuel mixer has a needle that can adjust the opening of the fuel pipe connected to the intake path from the LPG regulator, and a step motor that drives the needle.

Control devices for internal combustion engine systems that use natural gas, gasoline, or other fuels control the actuators that adjust the operating state based on detection signals from the various detection devices (various sensors) that detect the various operating states of the internal combustion engine, and adjust the amount of fuel injection so that the actual air-fuel ratio is close to the theoretical air-fuel ratio. However, the composition of fuels such as natural gas and gasoline varies depending on various factors such as the season and region, and each detection device and actuator has individual differences and deteriorates over long periods of use, so the actual air-fuel ratio can easily deviate from the theoretical air-fuel ratio.

Even if the actual air-fuel ratio deviates from the theoretical air-fuel ratio, it is possible to bring it closer to the theoretical air-fuel ratio using air-fuel ratio feedback control; however, if the deviation is large, it takes a long time for the air-fuel ratio feedback control to bring it closer to the theoretical air-fuel ratio, during which time the exhaust gas may not be sufficiently purified. Furthermore, since air-fuel ratio feedback control is generally started after the internal combustion engine has finished warming up, it is not possible to bring the air-fuel ratio closer to the theoretical air-fuel ratio using air-fuel ratio feedback control during warming up, and there is a possibility that the exhaust gas may not be sufficiently purified during warming up. For this reason, learning control has traditionally been used to correct the amount of fuel injection in order to eliminate the deviation between the actual air-fuel ratio and the theoretical air-fuel ratio.

For example, Patent Document 1 discloses a control device for a natural gas internal combustion engine that performs air-fuel ratio feedback control by calculating an air-fuel ratio correction coefficient according to the output of an oxygen concentration sensor ( _O2 sensor) provided in the exhaust system of the internal combustion engine and adjusting the fuel injection amount using the calculated air-fuel ratio correction coefficient. In Patent Document 1, the average value of the air-fuel ratio correction coefficient is further used as a parameter indicating the composition of the fuel, and the ignition timing is corrected accordingly.

JP 2000-2170 A

The control device for a natural gas internal combustion engine described in Patent Document 1 does not specifically mention learning control to correct the fuel injection amount, but generally, air-fuel ratio feedback control is continued during steady operation without acceleration or deceleration after the internal combustion engine has warmed up, and a learning value is calculated based on the operation and state of the air-fuel ratio correction coefficient. Therefore, since the learning value is calculated after the internal combustion engine has warmed up and when steady operation has continued for a relatively long time, it takes time for the learning value to be calculated, and in forklifts and the like that frequently accelerate and decelerate, the learning frequency becomes very low, which is not preferable. In particular, when refueling, if the composition of the refueled fuel varies relatively greatly, the deviation between the actual air-fuel ratio and the theoretical air-fuel ratio becomes large until the learning value is updated, which is not preferable.

The present invention was devised in consideration of these points, and aims to provide a control device for an internal combustion engine system that can quickly update the learning value that corrects the fuel injection amount, and quickly eliminate the discrepancy between the actual air-fuel ratio and the theoretical air-fuel ratio, thereby purifying exhaust gas more efficiently.

In order to solve the above problems, a first aspect of the present invention is a control device for an internal combustion engine system, the internal combustion engine system including an internal combustion engine, an air-fuel ratio related information detection device for detecting air-fuel ratio related information related to the air-fuel ratio of exhaust gas from the internal combustion engine, the control device for adjusting a fuel injection amount to the internal combustion engine by stoichiometric control using air-fuel ratio feedback control based on an operating state of the internal combustion engine including the air-fuel ratio related information, and a throttle device capable of adjusting a throttle valve of the internal combustion engine from the control device. The control device has a plurality of learning regions according to an intake amount of the internal combustion engine, stores learning values of each of the learning regions in a non-volatile storage device, and corrects the fuel injection amount to the internal combustion engine according to the operating state using the learning value corresponding to the learning region according to the intake amount of the internal combustion engine . The control device further includes a forced learning start determination unit which starts a forced learning mode for forcibly calculating the learning value for each of the learning regions when a forced learning execution instruction for forcibly calculating the learning value for correcting the fuel injection amount is input by a user or when a fuel supply detection unit which detects that fuel has been supplied determines that fuel has been supplied, a forced learning value calculation and storage unit which calculates the learning value for each of the learning regions based on a state of the air-fuel ratio feedback control based on the air-fuel ratio related information at the intake amount of the internal combustion engine which corresponds to the corresponding learning region when the forced learning mode is started and stores the calculated learning value for each of the learning regions in a non-volatile storage device, and a forced learning release unit which releases the forced learning mode when the calculation and storage of the learning value for each of the learning regions is completed by the forced learning value calculation and storage unit.In the forced learning mode, the control device is a control device for an internal combustion engine system, in which the forced learning value calculation and storage unit calculates and stores the learning value for each of the learning regions while automatically changing the intake amount of the internal combustion engine by adjusting the throttle device so as to be each of the learning regions .

Next, a second aspect of the present invention is a control device for an internal combustion engine system according to the first aspect of the present invention, wherein the internal combustion engine system has a load device capable of adjusting a load of the internal combustion engine from the control device. The control device has a plurality of learning regions corresponding to the rotation speed and intake air volume of the internal combustion engine, and stores the learning values of each of the learning regions in a non-volatile memory device. The fuel injection amount to the internal combustion engine corresponding to the operating state is corrected using the learning value corresponding to the learning region corresponding to the rotation speed and intake air volume of the internal combustion engine. When the forced learning mode is started, the control device has a forced learning value calculation and storage unit that calculates the learning value of each of the learning regions based on the state of the air-fuel ratio feedback control based on the air-fuel ratio related information at the rotation speed and intake air volume of the internal combustion engine that corresponds to the corresponding learning region, and stores the calculated learning value of each of the learning regions in a non-volatile memory device. In the forced learning mode, the control device calculates and stores the learning value of each of the learning regions while automatically changing the rotation speed and intake air volume of the internal combustion engine by adjusting the throttle device and the load device so that the learning region is achieved in the forced learning value calculation and storage unit. This is a control device for an internal combustion engine system.

Next, a third invention of the present invention is a control device for an internal combustion engine system according to the first or second invention , wherein the internal combustion engine system has an accelerator pedal operated by a user, and the control device is a control device for an internal combustion engine system, in which the forced learning value calculation/memory unit selects, from among the multiple learning areas, a multiple of the learning areas that correspond to an accelerator pedal depression amount, which is the amount of depression of the accelerator pedal by the user , before starting the forced learning mode.

Next, a fourth invention of the present invention is a control device for an internal combustion engine system relating to any one of the first to third inventions above, wherein the control device has a forced warm-up promotion unit that automatically promotes warm-up when it is determined that warm-up of the internal combustion engine has not been completed before starting the forced learning mode, and when warm-up is promoted by the forced warm-up promotion unit, the promotion of warm-up is terminated when warm-up is completed and processing of the forced learning value calculation and storage unit is transitioned to.

Next, a fifth aspect of the present invention is a control device for an internal combustion engine system, the internal combustion engine system including an internal combustion engine, an air-fuel ratio related information detection device for detecting air-fuel ratio related information related to the air-fuel ratio of exhaust gas from the internal combustion engine, the control device for adjusting a fuel injection amount to the internal combustion engine by stoichiometric control using air-fuel ratio feedback control based on an operating state of the internal combustion engine including the air-fuel ratio related information, an accelerator pedal operated by a user, and a throttle opening adjustment device for adjusting an opening of a throttle valve of the internal combustion engine in accordance with an operation amount of the accelerator pedal by the user. The control device has a plurality of learning regions corresponding to an intake amount of the internal combustion engine, and stores learning values of each of the learning regions in a non-volatile storage device, and corrects the fuel injection amount to the internal combustion engine corresponding to the operating state using the learning value corresponding to the learning region corresponding to the intake amount of the internal combustion engine. The control device also has a forced learning start determination unit that starts a forced learning mode forcibly calculating the learning values for each of the learning regions when a forced learning execution instruction for forcibly calculating the learning values that correct the fuel injection amount is input by a user or when a fuel refill detection unit that detects that fuel has been refilled determines that fuel has been refilled; a forced learning value calculation and storage unit that, when the forced learning mode is started, calculates the learning values for each of the learning regions based on a state of the air-fuel ratio feedback control that is based on the air-fuel ratio related information at the intake amount of the internal combustion engine that corresponds to the corresponding learning region and stores the calculated learning values for each of the learning regions in a non-volatile storage device; and a forced learning release unit that releases the forced learning mode when calculation and storage of the learning values for each of the learning regions is completed in the forced learning value calculation and storage unit. The internal combustion engine system has an information output device capable of outputting instructions to a user, and in the forced learning mode, the control device uses the information output device to output instructions to the user for the amount of accelerator pedal operation that will result in the intake volume for each learning region in the forced learning value calculation/memory unit, and calculates and stores the learning values for each learning region while allowing the user to change the intake volume of the internal combustion engine according to the amount of accelerator pedal operation.This is a control device for an internal combustion engine system.

Next, a sixth aspect of the present invention is a control device for an internal combustion engine system related to the fifth aspect of the present invention , wherein the control device selects, in the forced learning value calculation/storage unit, a plurality of learning regions corresponding to an accelerator pedal depression amount, which is the amount of depression of the accelerator pedal by a user , from among the plurality of learning regions before starting the forced learning mode.

Next, the seventh aspect of the present invention is a control device for an internal combustion engine system according to the fifth or sixth aspect of the present invention, the control device having a forced warm-up promotion unit that outputs a warm-up promotion instruction to a user using the information output device when it is determined that the warm-up of the internal combustion engine has not been completed before the forced learning mode is started, and when the warm-up is promoted by the forced warm-up promotion unit, the promotion of the warm-up is terminated when the warm-up is completed, and the control device for an internal combustion engine system transitions to processing by the forced learning value calculation and storage unit.

According to the first invention, when a forced learning execution instruction is input by the user, or when it is determined that fuel has been refueled, the learning values for each learning region according to the operating state are calculated and stored in a non-volatile memory device. This makes it possible to quickly update the learning values that correct the fuel injection amount, and quickly eliminate the discrepancy between the actual air-fuel ratio and the theoretical air-fuel ratio, thereby purifying the exhaust gas more efficiently.

According to the first aspect of the present invention, when calculating and storing the learning values of each learning region according to the operating state, the control device calculates and stores the learning values of each learning region while automatically changing the operating state of the internal combustion engine. Therefore, the user does not need to change (adjust) the operating state of the internal combustion engine, and can conveniently calculate and store the learning values of each learning region without any effort.

According to the third invention, before starting the forced learning mode, the user can specify the desired learning area from among multiple learning areas by the amount of depression of the accelerator pedal. Therefore, the user can calculate and store only the learning values of the learning areas that the user considers necessary, eliminating unnecessary time and shortening the time required for the forced learning mode. Furthermore, it is convenient because the control device calculates and stores the learning values of each learning area while automatically changing the operating state of the internal combustion engine.

It is preferable to execute the forced learning mode when the internal combustion engine has finished warming up. According to the fourth invention, it is convenient because the internal combustion engine can be automatically warmed up before starting the forced learning mode.

According to the fifth invention, in the case of a system that requires the user to change the operating state of the internal combustion engine when calculating and storing the learning values of each learning area according to the operating state, the information output device can appropriately instruct the user to change the operating state. Furthermore, the system can be configured more simply than a system in which the control device automatically changes the operating state of the internal combustion engine.

According to the sixth aspect of the present invention, before starting the forced learning mode, the user can specify a desired learning area from among a plurality of learning areas by the amount of depression of the accelerator pedal. Therefore, the user can calculate and store only the learning values of the learning areas that the user considers necessary, thereby eliminating wasted time and shortening the time required for the forced learning mode. Furthermore, the information output device can appropriately give instructions to the user to change the driving state.

It is preferable to execute the forced learning mode when the internal combustion engine has finished warming up. In the case of a system that requires the user to change the operating state of the internal combustion engine, the seventh invention makes it convenient to use an information output device to output instructions to the user to promote warming up of the internal combustion engine before starting the forced learning mode.

FIG. 1 is a diagram illustrating an example of a schematic configuration of an LPG engine system. FIG. 4 illustrates an example of a base step number profile for a fuel mixer stepper motor as a function of operating conditions. 5A and 5B are diagrams illustrating an example of base injection amount characteristics for an injector according to an operating state. FIG. 10 is a diagram for explaining the amount of fuel mixed into the intake air at the base step number of the step motor of the fuel mixer and the amount of fuel injected at the base injection amount of the injector. 10 is a flowchart illustrating an example of a processing procedure of "overall processing of forced learning" in the control device according to a first embodiment. 6 is a flowchart illustrating details of the refueling determination process in the flowchart shown in FIG. 5 . 6 is a flowchart illustrating details of the "warm-up promotion process" in the flowchart shown in FIG. 5. 10 is a flowchart illustrating an example of "control of the throttle device (throttle valve)" for driving the throttle device (throttle valve). 6 is a flowchart illustrating details of a forced learning value calculation and storage process in the flowchart shown in FIG. 5 . 10 is a diagram illustrating an example of a learning region GR(J, K) according to an operating state of the internal combustion engine. FIG. 10 is a flowchart illustrating details of the air-fuel ratio feedback control process in the flowchart shown in FIG. 9 . 10 is a flowchart illustrating details of the process of updating the learning value of the learning region GR(J, K) in the flowchart shown in FIG. 9 . 4 is a flowchart illustrating an example of a fuel injection amount calculation process for calculating a fuel injection amount injected from an injector. 5A to 5C are diagrams illustrating examples of operational waveforms in the first embodiment. 13 is a flowchart illustrating an example of a processing procedure of “overall processing of forced learning” according to the second embodiment. 16 is a flowchart illustrating details of the "warm-up promotion process" in the flowchart shown in FIG. 15. 11 is a diagram illustrating an example of a learning region GR(J) according to an operating state of the internal combustion engine. FIG. 16 is a flowchart illustrating details of the "forced learning value calculation and storage process" in the flowchart shown in FIG. 15. 19 is a flowchart illustrating details of the air-fuel ratio feedback control process in the flowchart shown in FIG. 18. 20 is a flowchart illustrating details of the process of updating the learning value of the learning region GR(J) in the flowchart shown in FIG. 18. 4 is a flowchart illustrating an example of a fuel injection amount calculation process for calculating a fuel injection amount injected from an injector. FIG. 11 is a diagram illustrating an example of an operational waveform in the second embodiment.

[Example of schematic configuration of LPG engine system 1 (Figure 1)]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. First, an example of a schematic configuration of an LPG engine system 1 will be described with reference to Fig. 1. In the description of this embodiment, the LPG engine system 1 mounted on a forklift will be described as an example of an internal combustion engine system.

The overall configuration of the LPG engine system 1 (corresponding to an internal combustion engine system) will be described below in order from the intake side to the exhaust side. Note that the intake pipes 11A, 11B and the intake manifold 11C correspond to the intake path, and the exhaust manifold 12A and the exhaust pipe 12B correspond to the exhaust path.

An air cleaner 21 is provided in the intake pipe 11A. The inlet side of the intake pipe 11B is connected to the outlet side of the intake pipe 11A.

The intake pipe 11B is provided with an intake flow rate detection device 15. The intake flow rate detection device 15 is, for example, an intake flow rate sensor, and outputs a detection signal corresponding to the flow rate of intake air flowing through the intake pipe 11B to the control device 60. The control device 60 can detect the intake flow rate based on the detection signal from the intake flow rate detection device 15.

Fuel pipe 33 of fuel mixer 30 is connected to intake pipe 11B. Main fuel pipe 51 from LPG regulator 50 is connected to fuel mixer 30, and fuel (fuel gas) is supplied from LPG regulator 50. Fuel supplied from main fuel pipe 51 flows from fuel pipe 33 to intake pipe 11B and is mixed with intake air. Fuel tank 53 is connected to LPG regulator 50, and fuel is supplied. Fuel tank 53 is provided with fuel quantity detection device 27. Fuel quantity detection device 27 is, for example, a fuel quantity sensor, and outputs a detection signal corresponding to the amount of fuel in fuel tank 53 to control device 60. Control device 60 can detect the amount of fuel in fuel tank 53 based on the detection signal from fuel quantity detection device 27.

Fuel mixer 30 is also provided with a step motor 31 and a needle 32, and control device 60 controls the position of needle 32 by controlling step motor 31, and can adjust the amount of fuel mixed into the intake air by adjusting the opening of fuel pipe 33. Fuel mixer 30 is provided in the intake path and mixes fuel into the intake air flowing through the intake path, and the amount of fuel to be mixed can be adjusted by step motor 31.

A throttle device 43 is provided downstream of the connection point of the intake pipe 11B with the fuel pipe 33. The throttle device 43 is also provided with a throttle valve 22 that adjusts the opening of the intake pipe 11B using an electric motor or the like in accordance with the amount of depression of the accelerator pedal by the user. The control device 60 detects the amount of depression of the accelerator pedal by the user based on a detection signal from an accelerator pedal depression amount detection device 16 (such as an accelerator pedal depression amount sensor), determines a target opening of the throttle valve 22 in accordance with the detected amount of depression, and outputs a control signal to the throttle device 43 so that the opening of the throttle valve 22 becomes the target opening.

An injector 40 is provided downstream of the throttle valve 22 in the intake pipe 11B. An auxiliary fuel pipe 52 from an LPG regulator 50 is connected to the injector 40, and fuel (fuel gas) is supplied from the LPG regulator 50. The fuel supplied from the auxiliary fuel pipe 52 is injected from the injector 40 into the intake pipe 11B. The control device 60 can adjust the amount of fuel injected from the injector (fuel injection amount) by controlling the injector 40.

The inlet side of the intake manifold 11C is connected to the outlet side of the intake pipe 11B. The outlet side of the intake manifold 11C is connected to the intake port of the LPG engine 10 (corresponding to an internal combustion engine). The intake manifold 11C is provided with a pressure detection device 23 (e.g., a pressure sensor). The control device 60 can detect the pressure of the intake air in the intake manifold 11C based on the detection signal from the pressure detection device 23.

The LPG engine 10 is provided with a rotation detection device 25 and a coolant temperature detection device 26. The rotation detection device 25 is, for example, a rotation sensor, and outputs a detection signal corresponding to the rotation angle of the crankshaft of the LPG engine 10 (i.e., engine speed) to the control device 60. The control device 60 can detect the rotation speed of the LPG engine 10 and the rotation angle of the crankshaft based on the detection signal from the rotation detection device 25. The coolant temperature detection device 26 is, for example, a temperature sensor, and outputs a detection signal corresponding to the temperature of the cooling coolant circulating within the LPG engine 10 to the control device 60. The control device 60 can detect the temperature of the cooling coolant based on the detection signal from the coolant temperature detection device 26.

The LPG engine system 1 also has a load device 45 that can adjust the load on the LPG engine 10. The load device 45 is a device that acts as a load on the LPG engine 10, and is, for example, an alternator for generating electricity, or a hydraulic pump in the case of a forklift. The control device 60 can adjust the increase or decrease of the load on the LPG engine 10 by outputting a control signal to the load device 45 to adjust the operation of the load device 45.

The LPG engine 10 is also provided with a spark plug 42. The control device 60 outputs an ignition signal to the spark plug 42 via the igniter 41.

The inlet side of the exhaust manifold 12A is connected to the exhaust port of the LPG engine 10, and the outlet side of the exhaust manifold 12A is connected to the inlet side of the exhaust pipe 12B.

The exhaust pipe 12B is provided with an air-fuel ratio related information detection device 24 (e.g., an _O2 sensor or an A/F sensor). _{The O2} sensor outputs a lean detection signal when the exhaust gas is in a lean state where oxygen is excessive relative to the theoretical air-fuel ratio, and outputs a rich detection signal when the exhaust gas is in a rich state where fuel is excessive relative to the theoretical air-fuel ratio. The A/F sensor outputs a detection signal according to the air-fuel ratio of the exhaust gas (including a lean state and a rich state). That is, the air-fuel ratio related information detection device 24 outputs air-fuel ratio related information related to a lean state and a rich state to the control device 60. The control device 60 can detect the value of the air-fuel ratio (in the case of an A/F sensor) or whether the air-fuel ratio is in a rich state or a lean state (in the case of an _O2 sensor) based on the air-fuel ratio related information from the air-fuel ratio related information detection device 24.

A three-way catalyst 70 (exhaust gas purification device) is connected to the outlet side of the exhaust pipe 12B. In order to efficiently purify the exhaust gas using the three-way catalyst 70, it is necessary to adjust the amount of fuel injection so that the air-fuel ratio is close to the theoretical air-fuel ratio.

The LPG engine system 1 is also provided with a forced learning instruction device 28 that allows the user to input a forced learning execution instruction that forcibly calculates a learning value that corrects the fuel injection amount. The forced learning instruction device 28 is, for example, a forced learning button, and when the control device 60 detects that the forced learning instruction device 28 has been operated, it determines that a forced learning execution instruction has been input by the user.

The LPG engine system 1 is also provided with information output devices 29A, 29B capable of outputting various information from the control device 60 to the user. An example of information output from the information output devices 29A, 29B is instruction information from the control device 60 to the user. The information output device 29A is, for example, a display, and can output instructions to the user by displaying characters, etc. based on a control signal from the control device 60. The information output device 29B is, for example, a speaker, and can output instructions to the user by outputting sound based on a control signal from the control device 60.

The control device 60 has a CPU 61, a RAM 62, a storage device 63 (ROM), a timer 64, a non-volatile storage device 65, etc. The control device 60 (CPU 61) receives detection signals from the various detection devices described above, and outputs control signals to the various actuators described above. The inputs and outputs of the control device 60 are not limited to the detection devices and actuators described above. In addition, the temperature and pressure of each part may be calculated by estimation without installing a sensor. The control device 60 detects the operating state of the LPG engine 10 based on detection signals from various detection devices including the above detection devices, and controls various actuators including the above actuators. The storage device 63 is, for example, a storage device such as a Flash-ROM, and stores programs and data for controlling the LPG engine 10 and performing self-diagnosis. The control device 60 (CPU 61) also has a refueling detection unit 61A, a forced learning start determination unit 61B, a forced warm-up promotion unit 61C, a forced learning value calculation/storage unit 61D, a forced learning cancellation unit 61E, etc., the details of which will be described later.

● [Base step number and base injection amount (Fig. 2 to Fig. 4)]
The amount of fuel supplied to the LPG engine 10 is the sum of the amount of fuel mixed with the intake air from the fuel mixer 30 and the amount of fuel injected from the injector 40 .

For example, the memory device 63 stores a base step number characteristic (see FIG. 2) in which a base step number (Sxx) is set according to the LPG engine speed (N1, N2, etc.) and the intake pressure (P1, P2, etc.) in the intake manifold 11C. The control device 60 detects the operating state of the LPG engine, controls the step motor 31 of the fuel mixer 30 based on the base step number determined according to the operating state, and adjusts the amount of fuel mixed into the intake air from the fuel mixer 30. Note that the base step number characteristic is not limited to the characteristic shown in FIG. 2 according to the LPG engine speed and the intake pressure in the intake manifold, and may be set according to various operating states.

For example, the memory device 63 stores a base injection amount characteristic (see FIG. 3) in which a base injection amount (Bxx) is set according to the LPG engine speed (N1, N2, etc.) and the intake pressure in the intake manifold (P1, P2, etc.). The control device 60 detects the operating state of the LPG engine, controls the injector 40 based on the base injection amount determined according to the operating state, and adjusts the amount of fuel injected from the injector 40 into the intake pipe 11B (fuel injection amount). Note that the base injection amount characteristic is not limited to the characteristic shown in FIG. 3 according to the LPG engine speed and the intake pressure in the intake manifold, and may be set according to various operating states.

Figure 4 shows an image of the amount of fuel supplied to the LPG engine 10. As described above, the LPG engine is supplied with a total amount of fuel Q, which is the sum of the amount of fuel M mixed into the intake air from the fuel mixer 30 and the amount of fuel B (base injection amount) injected from the injector. The control device 60 can instantly and precisely adjust the amount of fuel B (base injection amount) injected from the injector 40 between a lower limit amount Bmin and an upper limit amount Bmax, depending on the air-fuel ratio, etc., in comparison with the amount of fuel M from the fuel mixer 30.

As described above, the control device 60 adjusts the total fuel amount so that the air-fuel ratio is close to the theoretical air-fuel ratio depending on the operating state of the LPG engine 10. However, the actual air-fuel ratio is prone to deviate from the theoretical air-fuel ratio due to variations in fuel composition, individual differences in various actuators and sensors, and deterioration over time. To eliminate this deviation, the control device 60 performs stoichiometric control using air-fuel ratio feedback control based on the air-fuel ratio related information detected by the air-fuel ratio related information detection device 24.

Even if the actual air-fuel ratio deviates from the theoretical air-fuel ratio, it is possible to make the air-fuel ratio feedback control track the air-fuel ratio to a value close to the theoretical air-fuel ratio. However, if the deviation is large, it takes a long time for the air-fuel ratio feedback control to track the air-fuel ratio, during which the exhaust gas may not be sufficiently purified. In addition, since air-fuel ratio feedback control generally starts after the internal combustion engine has finished warming up, the air-fuel ratio feedback control cannot track the air-fuel ratio to a value close to the theoretical air-fuel ratio during warming up, and the exhaust gas may not be sufficiently purified during warming up. For this reason, learning control has traditionally been used to determine a learning value that corrects the fuel injection amount to eliminate the deviation between the actual air-fuel ratio and the theoretical air-fuel ratio.

In general learning control, air-fuel ratio feedback control is continued during steady operation without acceleration or deceleration after the internal combustion engine has warmed up, and the learning value is calculated based on the operation and state of the air-fuel ratio correction coefficient. Therefore, the learning value is calculated after the internal combustion engine has warmed up and when steady operation has continued for a relatively long time, so it takes time for the learning value to be calculated, and in forklifts and other vehicles that frequently accelerate and decelerate, the learning frequency is very low, which is not very preferable. Therefore, the "forced learning" process described below is performed by the control device 60, and the learning value that corrects the fuel injection amount is updated early, and the difference between the actual air-fuel ratio and the theoretical air-fuel ratio is eliminated early, resulting in more efficient purification of exhaust gas.

[Processing procedure of the control device 60 in the first embodiment (FIGS. 5 to 13) and example of operation waveforms (FIG. 14)]
[Overall process of forced learning (FIG. 5)] (first embodiment)
Next, an example of the processing procedure of "forced learning" by the control device 60 in the first embodiment will be described with reference to the flowcharts shown in Figures 5 to 13. In the first embodiment, in the LPG engine system 1 described with reference to Figure 1, the control device 60 controls the throttle device 43 to automatically change the operating state and obtain each learning value. Note that Figure 14 shows an example of the operating waveforms resulting from carrying out the processing shown in Figures 5 to 13.

The control device 60 (CPU 61) starts the process shown in FIG. 5 at a predetermined time interval (e.g., several ms) after the start of the LPG engine 10 (while the vehicle is stopped (vehicle speed = 0), in P or N range, and with the parking brake ON), and proceeds to step S010.

In step S010, the control device 60 executes the "refueling determination process" and proceeds to step S015. Details of the "refueling determination process" will be described later.

In step S015, the control device 60 determines whether the forced learning execution flag is ON. If the forced learning execution flag is ON (Yes), the control device 60 proceeds to step S035. If the forced learning execution flag is not ON (No), the control device 60 proceeds to step S020. The forced learning execution flag is a flag that is set ON in step S030 in FIG. 5 and set OFF in step S080, and is a flag that is set ON while "forced learning" is being performed (see "forced learning execution flag" in FIG. 14).

If the process proceeds to step S020, the control device 60 determines whether or not the forced learning button (forced learning instruction device 28) has been turned ON by the user. If the forced learning button has been turned ON (Yes), the control device 60 proceeds to step S030, and if not (No), the control device 60 proceeds to step S025.

When the process proceeds to step S025, the control device 60 determines whether the refueling flag is ON. If the refueling flag is ON (Yes), the control device 60 proceeds to step S030, and if not (No), the control device 60 ends the process shown in FIG. 5. The refueling flag is set to ON when it is determined in step S010 of FIG. 5 that fuel has been refueled, and is set to OFF in step S030, and is a flag stored in a non-volatile memory device.

When the process proceeds to step S030, the control device 60 sets the forced learning execution flag to ON, the refueling flag to OFF, and the warming-up flag to ON, and proceeds to step S035. In the example of FIG. 14, the forced learning button is turned ON at time T2, and the forced learning execution flag and the warming-up flag are set to ON. Note that the example of FIG. 14 shows an example of a case where it is not determined that fuel has been replenished. The warming-up flag is a flag that is set to ON during the period when the forced promotion process is being performed before executing the forced learning mode described later, and is a flag that is set to ON in step S030 in FIG. 5 and is set to OFF in step S090. Note that in step S030, the control device 60 outputs information to the effect that "forced learning is starting" from the information output devices 29A and 29B.

When the process proceeds to step S035, the control device 60 determines whether the warm-up flag is OFF. When the warm-up flag is OFF (Yes), the control device 60 determines that the warm-up is complete and proceeds to step S040. When the warm-up flag is ON (No), the control device 60 determines that the warm-up is still in progress and proceeds to step S090. When the accelerated warm-up is completed (when the warm-up flag is changed from ON to OFF), the control device 60 ends the accelerated warm-up and proceeds to the forced learning value calculation and storage process (step S070).

If the process proceeds to step S090, the control device 60 executes the "warm-up promotion process" and ends the process shown in FIG. 5. Details of the "warm-up promotion process" will be described later.

When the process proceeds to step S040, it is determined whether the forced learning mode flag is ON. If the forced learning mode flag is ON (Yes), the control device 60 proceeds to step S070, and if not (No), the control device 60 proceeds to step S045. The forced learning mode flag is a flag that is set to ON during the period when the "forced learning mode" is being performed, in which air-fuel ratio feedback control and calculation of the learning value are forcibly performed, and is a flag that is set to ON in step S065 in FIG. 5 and set to OFF in step S070.

When the process proceeds to step S045, the control device 60 determines whether the target area instruction reception flag is ON. If the target area instruction reception flag is ON (Yes), the control device 60 proceeds to step S053. If the target area instruction reception flag is not ON (No), the control device 60 proceeds to step S050. The target area instruction reception flag is set to ON when the user's accelerator pedal depression amount is acquired immediately before starting the "forced learning mode" and a learning area for which a learning value is to be calculated in the "forced learning mode" from among multiple learning areas according to the accelerator pedal depression amount is selected. The target area instruction reception flag is set to ON when acquisition of the accelerator pedal depression amount begins and is set to OFF when acquisition of the accelerator pedal depression amount ends.

If the process proceeds to step S050, the control device 60 initializes and starts the area instruction timer, sets the target area instruction reception flag to ON, and proceeds to step S053. As shown in the example of FIG. 14, the control device 60 sets the target area instruction reception flag to ON and starts the area instruction timer at the timing when the warm-up flag is changed from ON to OFF at time T3 (when warm-up is completed).

If the process proceeds to step S053, the control device 60 outputs information from the information output devices 29A and 29B to the effect that "Please indicate the upper limit of the learning area you wish to learn by the amount of depression of the accelerator pedal. The entire learning area will be learned by fully depressing the accelerator pedal."

[Example of learning region GR(J,K) (FIG. 10)]
An example of the learning region GR (J, K) is as shown in FIG. 10, and a plurality of learning regions GR (J, K) are set according to the operating state. The learning region GR (J, K) shown in FIG. 10 shows an example in which the learning region GR (J, K) is set according to the rotation speed and intake amount as the operating state of the LPG engine. For example, the learning region GR (2, 3) indicates that it is a learning region for an operating state in which the rotation speed is equal to or greater than N1 and less than N2, and the intake amount is equal to or greater than G2 and less than G3. A learning value is set for each of the learning regions GR (J, K), and each learning value is stored in a non-volatile storage device.

When the process proceeds to step S055, the control device 60 determines whether the area designation timer is equal to or greater than the designated waiting time. If the area designation timer is equal to or greater than the designated waiting time (Yes), the control device 60 proceeds to step S060, and if not (No), ends the process shown in FIG. 5. The designated waiting time is, for example, about 1 to 3 seconds.

When the process proceeds to step S060, the control device 60 acquires the accelerator pedal depression amount, sets the target upper limit (X, Y) according to the acquired accelerator pedal depression amount, and proceeds to step S065. For example, as shown in FIG. 10, when all learning areas GR (J, K) are learning areas GR (1, 1) to GR (4, 4), if the accelerator pedal depression amount is 0% or more and less than 25% (100% for full depression), the target upper limit (X, Y) is set to (1, 1), if the accelerator pedal depression amount is 25% or more and less than 50%, the target upper limit (X, Y) is set to (2, 2), if the accelerator pedal depression amount is 50% or more and less than 75%, the target upper limit (X, Y) is set to (3, 3), and if the accelerator pedal depression amount is 75% or more, the target upper limit (X, Y) is set to (4, 4). For example, when the target upper limit (X, Y) is set to (3, 3), the control device 60 outputs information from the information output devices 29A and 29B stating, "The accelerator pedal depression amount has been acquired. Of the learning ranges GR(1,1) to GR(4,4), learning ranges GR(1,1) to GR(3,3) will be learned" (when the target upper limit is set to (3,3), learning ranges GR(1,1), (1,2), (1,3), (2,1), (2,2), (2,3), (3,1), (3,2), and (3,3) will be learned).

In step S065, the control device 60 sets the forced learning mode flag to ON, sets the target area instruction acceptance flag to OFF, initializes the target area (J, K) to (1, 1), and proceeds to step S070. Note that the target area (J, K) indicates that the learning area GR (J, K) to be learned first in the "forced learning mode" executed in step S070 is learning area GR (1, 1).

In the example of FIG. 14, at time T4A, the "area instruction timer" becomes equal to or greater than the "instruction waiting time", so the control device 60 obtains the accelerator pedal depression amount, sets the "target upper limit" to (3, 3), sets the "target area" to (1, 1), changes the target area instruction acceptance flag from ON to OFF, and changes the forced learning mode flag from OFF to ON. Also, in the period from time T3 to time T4A, the user depresses the accelerator pedal to input an instruction for the upper limit of the learning area.

If the process proceeds to step S070, the control device 60 executes the "forced learning value calculation and storage process" (the "forced learning mode" process) and proceeds to step S075. Details of the "forced learning value calculation and storage process" will be described later.

In step S075, the control device 60 determines whether the forced learning mode flag is OFF. If the forced learning mode flag is OFF (Yes), the control device 60 proceeds to step S080, and if not (No), the control device 60 ends the process shown in FIG. 5.

If the process proceeds to step S080, the control device 60 sets the forced learning execution flag to OFF and ends the process shown in FIG. 5. In step S080, the control device 60 outputs information to the effect that "forced learning is ending" from the information output devices 29A and 29B. In the example of FIG. 14, since the forced learning mode flag is set to OFF at time T5, the control device 60 sets the forced learning execution flag to OFF and ends "forced learning".

[Refueling judgment process (Figure 6)]
Next, the details of the "refueling determination process" in step S010 in Fig. 5 will be described with reference to Fig. 6. When the control device 60 advances the process to step S010 shown in Fig. 5, the control device 60 advances the process to step S110 shown in Fig. 6.

In step S110, the control device 60 obtains the "previous fuel amount" stored in the non-volatile memory device, obtains the "current fuel amount" using the fuel amount detection device 27, and proceeds to step S115.

In step S115, the control device 60 determines whether the "current fuel amount" minus the "previous fuel amount" is equal to or greater than the refueling determination fuel amount. If the "current fuel amount" minus the "previous fuel amount" is equal to or greater than the refueling determination fuel amount (Yes), the control device 60 determines that fuel has been refueled and proceeds to step S120, and if not (No), the control device 60 proceeds to step S125.

If the process proceeds to step S120, the control device 60 sets the refueling flag set in the non-volatile memory device to ON and proceeds to step S125.

If the process proceeds to step S125, the control device 60 substitutes the "current fuel amount" for the "previous fuel amount" set in the non-volatile memory device, ends the process shown in FIG. 6, and returns to step S015 in FIG. 5.

● [Warm-up acceleration process (Fig. 7)]
Next, the warm-up promotion process in step S090 in Fig. 5 will be described in detail with reference to Fig. 7. When control device 60 advances the process to step S090 shown in Fig. 5, control device 60 advances the process to step S210 shown in Fig. 7.

In step S210, the control device 60 determines whether or not the warm-up of the LPG engine 10 has been completed. For example, the control device 60 determines that the warm-up has been completed when the coolant temperature detected using the coolant temperature detection device 26 is equal to or higher than the warm-up determination temperature (e.g., equal to or higher than 70°C). If the control device 60 determines that the warm-up has been completed (Yes), the process proceeds to step S220, and if the control device 60 determines that the warm-up has not been completed (No), the process proceeds to step S230.

If the process proceeds to step S220, the control device 60 controls the electric motor of the throttle device 43 to forcibly control the opening of the throttle valve 22 so that the rotation speed of the LPG engine 10 approaches the idle rotation speed (e.g., about 700 rpm), sets the warm-up flag to OFF, ends the process shown in FIG. 7, returns the process to below step S090 shown in FIG. 5, and ends the process in FIG. 5. In step S220, the control device 60 outputs information to the effect that "warm-up has been completed" from the information output devices 29A and 29B.

If the process proceeds to step S230, the control device 60 controls the electric motor of the throttle device 43 to forcibly control the opening of the throttle valve 22 so that the rotation speed of the LPG engine 10 approaches the warm-up promotion rotation speed (e.g., about 3000 [rpm]), ends the process shown in FIG. 7, returns the process to below step S090 shown in FIG. 5, and ends the process in FIG. 5. In step S230, the control device 60 outputs information to the effect that "the rotation speed will be increased to promote warm-up" from the information output devices 29A and 29B.

● [Control of the throttle device (throttle valve) (Figure 8)]
Next, the control of the throttle device 43 (throttle valve 22) will be described with reference to FIG. 8. The control of the throttle device (throttle valve) is obtained by adding step SA010 to the existing control of the throttle device (throttle valve). The control device 60 controls the electric motor of the throttle device 43 to control the opening of the throttle valve according to the amount of depression of the accelerator pedal by the user, but as shown in FIG. 14, during a period in which the "forced learning execution flag" is set to ON, the control device 60 forcibly controls the opening of the throttle valve 22 of the throttle device 43 to the "warm-up promotion rotation speed" during a period in which the "warm-up flag" is ON, regardless of the amount of depression of the accelerator pedal by the user, and forcibly controls the opening of the throttle valve 22 of the throttle device 43 to the operating state corresponding to each learning region GR (J, K) during a period in which the "forced learning mode flag" is ON. The control device 60 starts the process shown in FIG. 8 at a predetermined time interval (a time interval of about several ms), for example, and proceeds to step SA010.

In step SA010, the control device 60 determines whether the forced learning execution flag is ON. If the forced learning execution flag is ON (Yes), the control device 60 ends the process shown in FIG. 8, and if not (No), the control device 60 proceeds to step SA020.

If the process proceeds to step SA020, the control device 60 performs the existing control of the throttle device 43 (throttle valve 22), controls the opening of the throttle valve 22 of the throttle device 43 according to the amount of depression of the accelerator pedal by the user, and ends the process shown in FIG. 8.

● [Forced learning value calculation and storage process (Figure 9)]
Next, the details of the "forced learning value calculation and storage process" in step S070 in Fig. 5 will be described with reference to Fig. 9. When the control device 60 advances the process to step S070 shown in Fig. 5, the control device 60 advances the process to step S310 shown in Fig. 9. During the execution of the "forced learning value calculation and storage process", the "forced learning mode flag" is set to ON in Fig. 14. Note that (J, K) in the learning region GR(J, K) in Fig. 9 is the value of the target region at that time, and is initially (1, 1) set in step S065 in Fig. 5.

In step S310, the control device 60 forcibly controls the opening of the throttle valve 22 and the load of the load device 45 so that the learning region GR (J, K) corresponding to the target region (J, K) is set to (1, 1) when the control device 60 performs the processing of step S070 after the processing of step S065 shown in FIG. 5, so that the target region (J, K) is set to (1, 1), the control device 60 forcibly controls the opening of the throttle valve 22 and the load of the load device 45 so that the rotation speed is less than N1 and the intake amount is less than G1 so that the learning region GR (1, 1) shown in FIG. 10 is set. The control device 60 outputs information from the information output devices 29A and 29B to the effect that "the rotation speed and load will be automatically adjusted so that the learning region GR (J, K) (for example, the learning region GR (1, 1)) is set."

In step S320, the control device 60 executes the air-fuel ratio feedback control process and proceeds to step S330. Details of the air-fuel ratio feedback control process will be described later.

In step S330, the control device 60 executes the "update process for the learning value of the learning region GR (J, K)" and proceeds to step S340. Details of the "update process for the learning value of the learning region GR (J, K)" will be described later. If the target region is (1, 1), the learning value of the learning region GR (1, 1) is updated.

In step S340, the control device 60 determines whether learning of the learning area GR (J, K) is complete. If the target area is (1, 1), the control device 60 determines whether updating of the learning values of the learning area GR (1, 1) is complete. If updating of the learning values of the learning area GR (J, K) is complete (Yes), the control device 60 proceeds to step S345; if not (No), the control device 60 proceeds to step S350.

If the process proceeds to step S345, the control device 60 changes the target area (J, K) to the target area (J, K) for the next learning, and proceeds to step S350. For example, if the target upper limit is (3, 3) and the target area before the change is (1, 1), the control device 60 updates the next target area to (1, 2), and if the target area before the change is (2, 3), it changes the next target area to (3, 1).

When the process proceeds to step S350, the control device 60 determines whether the next target area (J, K) is an area that exceeds the target upper limit (X, Y). For example, if the target upper limit is (3, 3) and the next target area is (3, 4) or (4, 1), the control device 60 determines that the target upper limit (X, Y) has been exceeded. If the control device 60 determines that the next target area (J, K) exceeds the target upper limit (X, Y) (Yes), the process proceeds to step S355; if not (No), the process shown in FIG. 9 ends and the process returns to step S075 shown in FIG. 5.

If the process proceeds to step S355, the control device 60 sets the forced learning mode flag to OFF, terminates the process shown in FIG. 9, and returns the process to step S075 shown in FIG. 5.

In FIG. 14, at time T5, the control device 60 has completed updating the learning value of the learning region GR (3, 3) corresponding to the target upper limit (3, 3), and therefore has set the "forced learning mode flag" to OFF.

[Air-fuel ratio feedback control process (FIG. 11)]
Next, the "air-fuel ratio feedback control process" of step S320 shown in Fig. 9 will be described with reference to Fig. 11. The "air-fuel ratio feedback control process" is obtained by adding step SB010 to the existing "air-fuel ratio feedback control process." When the control device 60 advances the process to step S320 shown in Fig. 9, the control device 60 advances the process to step SB010 shown in Fig. 11.

In step SB010, the control device 60 determines whether the forced learning mode flag is ON. If the forced learning mode flag is ON (Yes), the control device 60 proceeds to step SB030, and if not (No), the control device 60 proceeds to step SB020.

When the process proceeds to step SB020, the control device 60 determines whether or not the (existing) feedback execution condition is satisfied. If the (existing) feedback execution condition is satisfied (Yes), the control device 60 proceeds to step SB030, and if not (No), the control device 60 proceeds to step SB040.

When the process proceeds to step SB030, the control device 60 executes the existing air-fuel ratio feedback control. For example, the control device 60 calculates the air-fuel ratio correction coefficient Kf based on the air-fuel ratio related information (air-fuel ratio value, or rich/lean) detected by the air-fuel ratio related information detection device 24. Note that the air-fuel ratio correction coefficient Kf is a correction coefficient that is multiplied when determining the fuel injection amount, as shown in FIG. 13, for example, and is set to a value within a range of 0.80 to 1.20 with 1.00 as the center. The method of calculating the air-fuel ratio correction coefficient Kf is the same as the existing method, so a description thereof will be omitted. The control device 60 then ends the process shown in FIG. 11 and returns to step S330 shown in FIG. 9.

If the process proceeds to step SB040, the control device 60 sets the air-fuel ratio correction coefficient Kf to 1.00, terminates the process shown in FIG. 11, and returns the process to step S330 shown in FIG. 9.

[Updating process of learning values in learning region GR (J, K) (FIG. 12)]
Next, the "update process of the learning value of the learning region GR (J, K)" in step S330 shown in Fig. 9 will be described with reference to Fig. 12. Note that the "update process of the learning value of the learning region GR (J, K)" is obtained by adding step SD010 to the existing "update process of the learning value of the learning region GR (J, K)". When the control device 60 advances the process to step S330 shown in Fig. 9, the control device 60 advances the process to step SD010 shown in Fig. 12.

In step SD010, the control device 60 determines whether the forced learning mode flag is ON. If the forced learning mode flag is ON (Yes), the control device 60 proceeds to step SD030, and if not (No), the control device 60 proceeds to step SD020.

When the process proceeds to step SD020, the control device 60 determines whether the execution conditions for the (existing) learning value update process are satisfied. If the execution conditions for the (existing) learning value update process are satisfied (Yes), the control device 60 proceeds to step SD030, and if not (No), the process shown in FIG. 12 ends and the process returns to step S340 shown in FIG. 9.

When the process proceeds to step SD030, the control device 60 executes the existing learning value update process. The control device 60 updates the learning value corresponding to the learning region GR (J, K) based on the operation, state, etc. of the air-fuel ratio correction coefficient Kf, and stores the updated learning value in the non-volatile storage device. For example, when the target region is (1, 1), the control device 60 updates the learning value corresponding to the learning region GR (1, 1) based on the operation, state, etc. of the air-fuel ratio correction coefficient Kf, and stores it in the non-volatile storage device. Note that the method of updating the learning value based on the operation and state of the air-fuel ratio correction coefficient Kf is similar to the existing method, so the explanation is omitted. Then, the control device 60 ends the process shown in FIG. 12, and returns the process to step S340 shown in FIG. 9.

In FIG. 14, during the period when the "forced learning mode flag" is ON, the control device 60 sequentially changes the target region (J, K) from (1, 1) to (1, 2)...(3, 2) to (3, 3), and sequentially updates the learning values of the corresponding learning regions (J, K). Note that in FIG. 14, for example, during the period from time T4A to time T4B, the control device 60 automatically adjusts the "throttle valve opening" and the "load of the load device" to be in the learning region GR (1, 1), and during the period from time T4E to time T4F, the control device 60 automatically adjusts the "throttle valve opening" and the "load of the load device" to be in the learning region GR (3, 2).

[Fuel injection amount calculation process (FIG. 13)]
Next, the "calculation process of fuel injection amount" will be described with reference to Fig. 13. The "calculation process of fuel injection amount" is not changed from the existing "calculation process of fuel injection amount". The control device 60 starts the process shown in Fig. 13 at a predetermined timing (for example, when the rotation angle of the crankshaft reaches a predetermined angle or at a predetermined time interval), and proceeds to step SE010.

In step SE010, the control device 60 calculates the fuel injection amount and ends the process shown in Fig. 13. In this example, the fuel injection amount is calculated by multiplying "the base injection amount shown in Fig. 3 + the learning value (the learning value corresponding to the learning region GR (J, K) according to the operating state at that time) + the other correction amount" by the air-fuel ratio correction coefficient Kf, and further by the other correction coefficient. Note that the other correction amount is, for example, a correction amount for increasing the amount of fuel during warm-up, and the other correction coefficient is, for example, a correction coefficient for increasing the amount during acceleration or a correction coefficient for decreasing the amount during deceleration.

In the above-mentioned "forced learning," when the user operates the forced learning button or when it is determined that fuel has been refueled, a learning value that corrects the amount of fuel is calculated, making it possible to obtain the learning value early and reflect it in the fuel injection amount.

As described above, before starting the forced learning mode (the forced learning value calculation and storage process in step S070 of FIG. 5), the control device 60 selects one or more learning areas from among multiple learning areas according to the amount of accelerator pedal depression by the user. The control device 60 then calculates and stores the learning value for each learning area while automatically changing the operating state of the LPG engine so that the selected learning area is reached.

[Processing procedure of the control device 60 in the second embodiment (FIGS. 15 to 21) and example of operation waveforms (FIG. 22)]
[Overall process of forced learning (FIG. 15)] (Second embodiment)
Next, an example of the processing procedure of "forced learning" by the control device 60 in the second embodiment will be described with reference to the flowcharts shown in Figs. 15 to 22. In the above-mentioned first embodiment, the control device 60 uses the electric motor of the throttle device 43 to control the opening of the throttle valve 22 and the like to automatically change the driving state and obtain each learning value. However, in the second embodiment, the throttle device 43 does not have an electric motor, and the opening of the throttle valve 22 is directly controlled from the accelerator pedal via a cable or the like. In the second embodiment, the information output devices 29A and 29B instruct the user to depress the accelerator pedal, and obtain the learning values of each learning region while the user changes the driving state. The second embodiment differs from the first embodiment mainly in the above points. The main differences from the first embodiment will be described below.

[Example of learning region GR(J) (FIG. 17)]
In the second embodiment, as shown in Fig. 17, a plurality of learning regions GR(J) are set according to the operating state. The learning region GR(J) shown in Fig. 17 is set according to the intake air volume as the operating state of the LPG engine. For example, the learning region GR(2) indicates that the learning region is set for an operating state in which the intake air volume is equal to or greater than G1 and less than G2. A learning value is set for each of the learning regions GR(J), and each learning value is stored in a non-volatile storage device.

The flowchart in FIG. 15, which is the overall process of forced learning in the second embodiment, differs from the flowchart in FIG. 5 in the parts framed in bold, with step S060 changed to step S060B, step S065 changed to step S065B, the processing content of step S070 changed, and the processing content of step S090 changed. The other steps are the same as those in the flowchart shown in FIG. 5, so a description thereof will be omitted.

If the process proceeds to step SB060B, the control device 60 acquires the accelerator pedal depression amount, sets the target upper limit (X) according to the acquired accelerator pedal depression amount, and proceeds to step S065B. For example, as shown in FIG. 17, if all learning areas GR(J) are learning areas GR(1) to GR(4), if the accelerator pedal depression amount is 0% or more and less than 25% (full depression is 100%), the target upper limit (X) is set to (1), if the accelerator pedal depression amount is 25% or more and less than 50%, the target upper limit (X) is set to (2), if the accelerator pedal depression amount is 50% or more and less than 75%, the target upper limit (X) is set to (3), and if the accelerator pedal depression amount is 75% or more, the target upper limit (X) is set to (4). For example, when the target upper limit (X) is set to (3), the control device 60 outputs information from the information output devices 29A and 29B stating, "The accelerator pedal depression amount has been acquired. Of the learning areas GR(1) to GR(4), learning areas GR(1) to GR(3) will be learned" (in this example, learning areas GR(1), (2), and (3) will be learned).

In step S065B, the control device 60 sets the forced learning mode flag to ON, sets the target area instruction acceptance flag to OFF, initializes the target area (J) to (1), and proceeds to step S070. Note that the target area (J) indicates that the learning area GR(J) to be learned first in the "forced learning mode" executed in step S070 is learning area GR(1).

● [Refueling judgment process]
The "refueling determination process" in the second embodiment is the same as the "refueling determination process" in the first embodiment shown in Fig. 6, and therefore a description thereof will be omitted. Note that, as shown by the "refueling flag" in Fig. 22, the second embodiment shows an example in which "forced learning" is started at the start after refueling.

● [Warm-up acceleration process (Fig. 16)]
Next, the details of the "warm-up promotion process" in step S090 in Fig. 15 will be described with reference to Fig. 16. When the control device 60 advances the process to step S090 shown in Fig. 15, the control device 60 advances the process to step S210 shown in Fig. 16. Compared to the "warm-up promotion process" of the first embodiment shown in Fig. 7, the "warm-up promotion process" of the second embodiment shown in Fig. 16 has been changed in the parts indicated by bold frames, with step S220 being changed to step S220B and step S230 being changed to step S230B.

If the process proceeds to step S220B, the control device 60 uses the information output devices 29A and 29B to output instructions to the user so that the rotation speed of the LPG engine 10 approaches the idle rotation speed (e.g., approximately 700 rpm), ends the process shown in FIG. 16, returns the process to below step S090 shown in FIG. 15, and ends the process in FIG. 15. In step S220B, the control device 60 outputs information from the information output devices 29A and 29B to the effect that "Warm-up is complete. Please take your foot off the accelerator pedal to set the rotation speed to idle."

If the process proceeds to step S230B, the control device 60 uses the information output devices 29A and 29B to output instructions to the user so that the rotation speed of the LPG engine 10 approaches the warm-up promotion rotation speed (e.g., approximately 3000 [rpm]), ends the process shown in FIG. 16, returns the process to below step S090 shown in FIG. 15, and ends the process in FIG. 15. In step S230B, the control device 60 outputs information from the information output devices 29A and 29B to the effect that "in order to promote warm-up, please depress the accelerator pedal to set the warm-up promotion rotation speed (e.g., approximately 3000 [rpm])."

● [Throttle device (throttle valve) control]
In the second embodiment, as described above, the throttle device 43 does not have an electric motor, and the opening of the throttle valve 22 is directly controlled from the accelerator pedal via a cable or the like, so the "control of the throttle device (throttle valve)" of the first embodiment shown in Figure 8 is omitted.

● [Forced learning value calculation and storage process (Figure 18)]
Next, the details of the [forced learning value calculation and storage process] in step S070 in FIG. 15 will be described with reference to FIG. 18. When the control device 60 advances the process to step S070 shown in FIG. 15, the control device 60 advances the process to step S310B shown in FIG. 18. Compared to the [forced learning value calculation and storage process] in the first embodiment shown in FIG. 9, the [forced learning value calculation and storage process] in the second embodiment shown in FIG. 18 has been changed in the parts shown in the thick frame, and has been significantly changed. During the [forced learning value calculation and storage process], the "forced learning mode flag" is set to ON in FIG. 22. The (J) in the learning region GR(J) in FIG. 18 is the value of the target region at that time, and is initially set to (1) in step S065B in FIG. 15.

In step S310B, the control device 60 outputs instructions to the user from the information output devices 29A and 29B so as to set the learning area GR(J) corresponding to the target area (J), and proceeds to step S315B.

The memory device 63 of the control device 60 stores the rotation speed N(1) (e.g., about 1000 [rpm]) corresponding to the learning region GR(1), the rotation speed N(2) (e.g., about 2000 [rpm]) corresponding to the learning region GR(2), the rotation speed N(3) (e.g., about 3000 [rpm]) corresponding to the learning region GR(3), and the rotation speed N(4) (e.g., about 4000 [rpm]) corresponding to the learning region GR(4). When the processing of step S070 is performed after the processing of step S065B shown in FIG. 15, the target region (J) is set to (1). In this case, the control device 60 uses the information output devices 29A and 29B to output information to the effect that "Please depress the accelerator pedal to set the rotation speed N(1) (about 1000 [rpm]) so as to be in the learning region GR(1) shown in FIG. 17."

In step S315B, the control device 60 acquires the rotation speed of the LPG engine and determines whether the acquired rotation speed is within the range of rotation speed N(J) ± ΔN (approximately ±200 [rpm]). If the acquired rotation speed is within the range of rotation speed N(J) ± ΔN (Yes), the control device 60 proceeds to step S320, and if not (No), the control device 60 proceeds to step S340B. The user adjusts the amount of depression of the accelerator pedal so that the actual rotation speed is within the range of rotation speed N(J) ± ΔN.

When the process proceeds to step S320, the control device 60 executes an air-fuel ratio feedback control process, and proceeds to step S330 . The details of the air-fuel ratio feedback control process will be described later, but the content of the air-fuel ratio feedback control process in the second embodiment is slightly different from the content of the air-fuel ratio feedback control process in the first embodiment shown in FIG.

In step S330 , the control device 60 executes "update processing of the learning value of the learning region GR(J)" and proceeds to step S340B. Details of the "update processing of the learning value of the learning region GR(J)" will be described later, but the content of the "update processing of the learning value of the learning region GR(J)" in the second embodiment is slightly different from the content of the "update processing of the learning value of the learning region GR(J,K)" in the first embodiment shown in Fig. 12. Note that when the target region is (1), the learning value of the learning region GR(1) is updated.

In step S340B, the control device 60 determines whether learning of the learning area GR(J) is complete. If the target area is (1), the control device 60 determines whether updating of the learning values of the learning area GR(1) is complete. If updating of the learning values of the learning area GR(J) is complete (Yes), the control device 60 proceeds to step S345B, and if not (No), the control device 60 proceeds to step S350B.

If the process proceeds to step S345B, the control device 60 changes the target area (J) to the target area (J) for the next learning, and proceeds to step S350B. For example, if the target upper limit is (3) and the target area before the change is (1), the control device 60 updates it to (2) as the next target area, and if the target area before the change is (3), it changes it to (4) as the next target area.

When the process proceeds to step S350B, the control device 60 determines whether the next target area (J) is an area that exceeds the target upper limit (X). For example, if the target upper limit is (3) and the next target area is (4), the control device 60 determines that the target upper limit (X) has been exceeded. If the control device 60 determines that the next target area (J) exceeds the target upper limit (X) (Yes), the process proceeds to step S355; if not (No), the process shown in FIG. 18 ends and the process returns to step S075 shown in FIG. 15.

If the process proceeds to step S355, the control device 60 sets the forced learning mode flag to OFF, terminates the process shown in FIG. 18, and returns the process to step S075 shown in FIG. 15.

In FIG. 22, at time T6, the control device 60 has completed updating the learning value of the learning region GR(3) corresponding to the target upper limit (3), and therefore has set the "forced learning mode flag" to OFF.

Air-fuel ratio feedback control process (FIG. 19)
Next, the "air-fuel ratio feedback control process" of step S320 shown in Fig. 18 will be described with reference to Fig. 19. The "air-fuel ratio feedback control process" is obtained by adding step SB010 to the existing "air-fuel ratio feedback control process." When the control device 60 advances the process to step S320 shown in Fig. 18, the control device 60 advances the process to step SB010 shown in Fig. 19.

In step SB010, the control device 60 determines whether the forced learning mode flag is ON. If the forced learning mode flag is ON (Yes), the control device 60 proceeds to step SB030, and if not (No), the control device 60 proceeds to step SB020.

When the process proceeds to step SB020, the control device 60 determines whether or not the (existing) feedback execution condition is satisfied. If the (existing) feedback execution condition is satisfied (Yes), the control device 60 proceeds to step SB030B, and if not (No), the control device 60 proceeds to step SB040B.

When the process proceeds to step SB030B, the control device 60 executes the existing air-fuel ratio feedback control. For example, the control device 60 calculates the air-fuel ratio correction amount Mf based on the air-fuel ratio related information (air-fuel ratio value, or rich/lean) detected by the air-fuel ratio related information detection device 24. The air-fuel ratio correction amount Mf is a correction amount added when determining the fuel injection amount, as shown in FIG. 21, for example, and is set to a value within a range of, for example, −A1 [ms] to +A2 [ms] (or −A3 [mm ³ ] to +A4 [mm ³ ], etc.) with 0.00 as the center. The method of calculating the air-fuel ratio correction amount Mf is the same as the existing method, so a description thereof will be omitted. Then, the control device 60 ends the process shown in FIG. 19 and returns the process to step S330 shown in FIG. 18.

If the process proceeds to step SB040B, control device 60 sets the air-fuel ratio correction amount Mf to 0.00, terminates the process shown in FIG. 19, and returns the process to step S330 shown in FIG.

[Updating process of learning value of learning region GR(J) (FIG. 20)]
Next, the "update process of the learning value of the learning region GR(J)" in step S330 shown in Fig. 18 will be described with reference to Fig. 20. The "update process of the learning value of the learning region GR(J)" is obtained by adding step SD010 to the existing "update process of the learning value of the learning region GR(J)". When the control device 60 advances the process to step S330 shown in Fig. 18, the control device 60 advances the process to step SD010 shown in Fig. 20.

In step SD010, the control device 60 determines whether the forced learning mode flag is ON. If the forced learning mode flag is ON (Yes), the control device 60 proceeds to step SD030, and if not (No), the control device 60 proceeds to step SD020.

When the process proceeds to step SD020, the control device 60 determines whether the execution conditions for the (existing) learning value update process are satisfied. If the execution conditions for the (existing) learning value update process are satisfied (Yes), the control device 60 proceeds to step SD030B, and if not (No), the control device 60 ends the process shown in FIG. 20 and returns to step S340B shown in FIG. 18.

When the process proceeds to step SD030B, the control device 60 executes the existing learning value update process. The control device 60 updates the learning value corresponding to the learning region GR(J) based on the operation, state, etc. of the air-fuel ratio correction amount Mf, and stores the updated learning value in the non-volatile storage device. For example, when the target region is (1), the control device 60 updates the learning value corresponding to the learning region GR(1) based on the operation, state, etc. of the air-fuel ratio correction amount Mf, and stores the updated learning value in the non-volatile storage device. Note that the method of updating the learning value based on the operation and state of the air-fuel ratio correction amount Mf is similar to the existing method, so the explanation is omitted. Then, the control device 60 ends the process shown in FIG. 20, and returns the process to step S340B shown in FIG. 18.

In FIG. 22, during the period when the "forced learning mode flag" is ON, the control device 60 changes the target region (J) from (1) to (2) to (3) in sequence, and updates the learning value of the corresponding learning region (J) in sequence. Note that in FIG. 22, the user adjusts the accelerator pedal depression amount so that the rotation speed becomes N(1) during the period from time T4A to time T4B, for example.

[Fuel injection amount calculation process (FIG. 21)]
Next, the "calculation process of fuel injection amount" will be described with reference to Fig. 21. The "calculation process of fuel injection amount" is not changed from the existing "calculation process of fuel injection amount", but the content of the "calculation process of fuel injection amount" of the second embodiment shown in Fig. 21 is slightly different from the content of the "calculation process of fuel injection amount" of the first embodiment shown in Fig. 13. The control device 60 starts the process shown in Fig. 21 at a predetermined timing (for example, at a timing when the rotation angle of the crankshaft reaches a predetermined angle or at a predetermined time interval), and proceeds to step SE010B.

In step SE010B, the control device 60 calculates the fuel injection amount and ends the process shown in FIG. 21. In this example, the fuel injection amount is calculated by multiplying the "base injection amount shown in FIG. 2 + learning value (learning value corresponding to the learning region GR(J) according to the driving state at that time) + air-fuel ratio correction amount Mf + other correction amount" by the other correction coefficient. Note that the other correction amount is, for example, a correction amount for increasing the amount of fuel during warm-up, and the other correction coefficient is, for example, a correction coefficient that increases during acceleration or a correction coefficient that decreases during deceleration.

As described above, before starting the forced learning mode (the forced learning value calculation and storage process in step S070 of FIG. 15), the control device 60 selects one or more learning areas from among the multiple learning areas according to the amount of accelerator pedal depression by the user. The control device 60 then uses the information output device to output instructions to the user so as to enter each of the selected learning areas, and calculates and stores the learning values for each learning area while having the user change the operating state of the LPG engine.

In the "forced learning" of the first and second embodiments described above, when the user operates the forced learning button or when it is determined that fuel has been refueled, a learning value that corrects the amount of fuel is calculated, making it possible to obtain the learning value early and reflect it in the amount of fuel injection.

The control device 60 (CPU 61) that executes the [refueling determination process] shown in FIG. 6 corresponds to the refueling detection unit 61A (see FIG. 1) that detects that fuel has been refueled.

The control device 60 (CPU 61) that executes the processes of steps S015 to S030 shown in FIG. 5 and FIG. 15 corresponds to a forced learning start determination unit 61B (see FIG. 1) that starts a forced learning mode in which the learning values of each learning region are forcibly calculated when a forced learning execution instruction that forcibly calculates a learning value that corrects the fuel injection amount is input by the user, or when a fuel refill detection unit 61A (see FIG. 1) that detects that fuel has been refilled determines that fuel has been refilled.

The control device 60 (CPU 61) that executes the [warm-up promotion process] in Figures 6 and 16 corresponds to a forced warm-up promotion unit 61C (see Figure 1) that automatically promotes warm-up or outputs a warm-up promotion instruction to the user if it is determined that the internal combustion engine has not been warmed up before the forced learning mode is started.

The control device 60 (CPU 61) which executes the [forced learning value calculation and storage process], [air-fuel ratio feedback control process], and [learning area learning value update process] in Figures 9, 11, 12, 18, 19, and 20 corresponds to a forced learning value calculation and storage unit 61D (see Figure 1) which, when the forced learning mode is started, calculates the learning value of each learning area based on the state of air-fuel ratio feedback control based on the air-fuel ratio related information in the operating state which becomes the corresponding learning area, and stores the calculated learning value of each learning area in a non-volatile storage device.

The control device 60 (CPU 61) which executes the processes of steps S350 and S355 in FIG. 9, steps S350B and S355 in FIG. 18, and steps S075 and S080 in FIG. 5 and FIG. 15 corresponds to a forced learning cancellation unit 61E (see FIG. 1) which cancels the forced learning mode when the forced learning value calculation/storage unit 61D (see FIG. 1) has finished calculating and storing the learning values for each learning area.

As described above, the "forced learning" described in the first and second embodiments makes it possible to achieve stable combustion (control close to the theoretical air-fuel ratio) without waiting for the start of air-fuel ratio feedback control (after warming up), even when fuel with a large variation in composition is refueled. In addition, the fuel injection amount becomes appropriate, which contributes to improving fuel efficiency. In addition, since there is more leeway in the air-fuel ratio feedback control, the range of controllable heat generation can be expanded. Furthermore, even if the air-fuel ratio related information detection device breaks down after the end of "forced learning" and air-fuel ratio feedback control is no longer possible, the engine is less likely to stall and evacuation driving can be performed appropriately.

The control device for an internal combustion engine system of the present invention is not limited to the configuration, structure, processing procedure, etc. described in this embodiment, and various modifications, additions, and deletions are possible without changing the gist of the present invention. For example, the processing procedure is not limited to the flowchart described in this embodiment, and the operating waveforms are not limited to the waveforms shown in Figures 14 and 22.

In the description of this embodiment, an _O2 sensor that detects a rich state/lean state is used as an example of an air-fuel ratio related information detection device that outputs air-fuel ratio related information, but an A/F sensor that detects the value of the air-fuel ratio may be used instead of the _O2 sensor.

The control device for an LPG engine system of the present invention is not limited to LPG engines, but can also be applied to internal combustion engine systems using natural gas engines, gasoline engines, etc., which control the air-fuel ratio with stoichiometric control (controlling the air-fuel ratio to be close to the theoretical air-fuel ratio) using air-fuel ratio feedback control based on air-fuel ratio related information. In addition, in the description of this embodiment, a forklift is used as an example, but the present invention is not limited to forklifts and can be applied to various internal combustion engine systems that adjust the air-fuel ratio with stoichiometric control.

In the description of this embodiment, the forced learning flag is set to ON and "forced learning" is executed when at least one of the following is detected: the user operates the forced learning instruction device 28 (forced learning button) or when refueling is detected; however, the refueling step may be omitted and "forced learning" may be executed by the user only operating the forced learning instruction device 28 (forced learning button).

In addition, learning values corresponding to each learning region may be prepared separately for after warm-up and during warm-up, and the [warm-up promotion process] may be omitted, and during warm-up the learning values during warm-up may be calculated and stored and reflected in the fuel injection amount, and after warm-up the learning values after warm-up may be calculated and stored and reflected in the fuel injection amount.

In addition, the processing of steps S045 to S060 in FIG. 5 or steps S045 to S060B in FIG. 15 may be omitted, and the target upper limit (X, Y) (or (X)) may always be set to the upper limit of the learning area, so that the learning values of all learning areas (J, K) (or (J)) are always calculated and stored. In addition, the number of learning areas is not limited to the number described in this embodiment, and may be any appropriate number based on the driving state.

In the first embodiment, as shown in FIG. 10, the learning region (J, K) is set based on the intake volume and the rotation speed, but it may be set based on various operating conditions, such as the intake pressure and the rotation speed, or the load and the rotation speed. Similarly, in the second embodiment, as shown in FIG. 17, the learning region (J) is set based on the intake volume, but it may be set based on various operating conditions, such as the intake pressure or the load. In addition, in both the first and second embodiments, the intake flow detection device 15 may be omitted, and the intake pressure and the rotation speed may be converted to the intake volume.

In addition, a manual on the operating procedures for "forced learning" can be prepared to allow the user to understand the operations when "forced learning" is executed, and although information output devices 29A and 29B may be omitted, it is preferable to have information output devices 29A and 29B.

In addition, after updating and storing the learning values of each learning area using the "forced learning" described in this embodiment, the learning values may be further updated and stored using conventional learning control (updating and storing the learning values of the learning area according to the operating state at that time when a steady state that is not a transient state continues). The "forced learning" described in this embodiment may be added to the conventional learning control, or the "forced learning" described in this embodiment may be implemented instead of the conventional learning control.

In addition, terms such as "greater than or equal to" (≧), "less than or equal to" (≦), "greater than" (>), and "less than" (<) may or may not include an equal sign. In addition, the numerical values used in the explanation of this embodiment are merely examples, and the present invention is not limited to these numerical values.

1. LPG engine system (internal combustion engine system)
10 LPG engine (internal combustion engine)
11A, 11B Intake pipe 11C Intake manifold 12A Exhaust manifold 12B Exhaust pipe 15 Intake flow rate detector 16 Accelerator pedal depression amount detector 21 Air cleaner 22 Throttle valve 23 Pressure detector 24 Air-fuel ratio related information detector 25 Revolution detector 26 Coolant temperature detector 27 Fuel amount detector 28 Forced learning instruction device (forced learning button)
29A Information output device (display)
29B Information output device (speaker)
30 Fuel mixer 31 Step motor 32 Needle 33 Fuel pipe 40 Injector 41 Igniter 42 Spark plug 43 Throttle device 45 Load device (alternator, hydraulic pump)
50 LPG regulator 51 main fuel pipe 52 auxiliary fuel pipe 53 fuel tank 60 control device 61 CPU
61A Refueling detection unit 61B Forced learning start determination unit 61C Forced warm-up promotion unit 61D Forced learning value calculation/storage unit 61E Forced learning cancellation unit 62 RAM
63 Storage device (ROM)
64 Timer 65 Non-volatile memory device 70 Three-way catalyst

Claims (7)

A control device for an internal combustion engine system,
The internal combustion engine system includes:
An internal combustion engine;
an air-fuel ratio related information detection device for detecting air-fuel ratio related information relating to the air-fuel ratio of exhaust gas from the internal combustion engine;
the control device adjusts a fuel injection amount to the internal combustion engine through stoichiometric control using an air-fuel ratio feedback control based on an operating state of the internal combustion engine including the air-fuel ratio related information; and
a throttle device capable of adjusting a throttle valve of the internal combustion engine from the control device;
It has
The control device includes:
a plurality of learning regions corresponding to an intake amount of the internal combustion engine , and a learning value of each of the learning regions is stored in a non-volatile storage device;
the fuel injection amount to the internal combustion engine according to the operating state is corrected using the learning value corresponding to the learning region according to an intake amount of the internal combustion engine ,
a forced learning start determination unit which starts a forced learning mode in which the learning values for each of the learning regions are forcibly calculated when a forced learning execution instruction for forcibly calculating the learning values for correcting the fuel injection amount is input by a user or when a refueling detection unit which detects that refueling has occurred determines that refueling has occurred;
a forced learning value calculation and storage unit that, when the forced learning mode is started, calculates the learning value of each of the learning regions based on a state of the air-fuel ratio feedback control that is based on the air-fuel ratio related information at an intake amount of the internal combustion engine that corresponds to the corresponding learning region, and stores the calculated learning value of each of the learning regions in a non-volatile storage device;
a forced learning canceling unit that cancels the forced learning mode when the forced learning value calculation/storage unit has completed calculation and storage of the learning values for each of the learning regions;
having
In the forced learning mode, the control device
the forced learning value calculation and storage unit calculates and stores the learning values for each of the learning regions while automatically changing the intake amount of the internal combustion engine by adjusting the throttle device so as to achieve each of the learning regions;
A control device for an internal combustion engine system. 2. The control device for an internal combustion engine system according to claim 1,
The internal combustion engine system includes:
a load device capable of adjusting a load of the internal combustion engine from the control device,
The control device includes:
a plurality of learning regions corresponding to a rotation speed and an intake amount of the internal combustion engine, and the learning values of the respective learning regions are stored in a non-volatile storage device;
the fuel injection amount to the internal combustion engine according to the operating state is corrected using the learning value corresponding to the learning region according to the rotation speed and intake amount of the internal combustion engine,
a forced learning value calculation and storage unit that, when the forced learning mode is started, calculates the learning value of each of the learning regions based on a state of the air-fuel ratio feedback control based on the air-fuel ratio related information at the rotation speed and intake amount of the internal combustion engine that correspond to the corresponding learning region, and stores the calculated learning value of each of the learning regions in a non-volatile storage device;
In the forced learning mode, the control device
the forced learning value calculation/storage unit calculates and stores the learning values for each of the learning regions while automatically changing the rotation speed and the intake amount of the internal combustion engine by adjusting the throttle device and the load device so as to be in each of the learning regions;
A control device for an internal combustion engine system. The control device for an internal combustion engine system according to claim 1 or 2 ,
the internal combustion engine system has an accelerator pedal operated by a user;
The control device includes:
before starting the forced learning mode, the forced learning value calculation and storage unit selects, from the plurality of learning regions, a plurality of learning regions corresponding to an accelerator pedal depression amount, which is a depression amount of the accelerator pedal by a user .
A control device for an internal combustion engine system. The control device for an internal combustion engine system according to any one of claims 1 to 3 ,
The control device includes:
a forced warm-up promotion unit that automatically promotes warm-up of the internal combustion engine when it is determined that the warm-up of the internal combustion engine has not been completed before starting the forced learning mode,
In the case where the warm-up is promoted by the forced warm-up promotion unit, when the warm-up is completed, the promotion of the warm-up is terminated and the process proceeds to the forced learning value calculation and storage unit.
A control device for an internal combustion engine system. A control device for an internal combustion engine system,
The internal combustion engine system includes:
An internal combustion engine;
an air-fuel ratio related information detection device for detecting air-fuel ratio related information relating to the air-fuel ratio of exhaust gas from the internal combustion engine;
the control device adjusts a fuel injection amount to the internal combustion engine through stoichiometric control using an air-fuel ratio feedback control based on an operating state of the internal combustion engine including the air-fuel ratio related information; and
An accelerator pedal operated by a user;
a throttle opening adjustment device that adjusts an opening of a throttle valve of the internal combustion engine in response to an amount of operation of the accelerator pedal by a user;
It has
The control device includes:
a plurality of learning regions corresponding to an intake amount of the internal combustion engine, and a learning value of each of the learning regions is stored in a non-volatile storage device;
the fuel injection amount to the internal combustion engine according to the operating state is corrected using the learning value corresponding to the learning region according to an intake amount of the internal combustion engine,
a forced learning start determination unit which starts a forced learning mode in which the learning values for each of the learning regions are forcibly calculated when a forced learning execution instruction for forcibly calculating the learning values for correcting the fuel injection amount is input by a user or when a refueling detection unit which detects that refueling has occurred determines that refueling has occurred;
a forced learning value calculation and storage unit that, when the forced learning mode is started, calculates the learning value of each of the learning regions based on a state of the air-fuel ratio feedback control that is based on the air-fuel ratio related information at an intake amount of the internal combustion engine that corresponds to the corresponding learning region, and stores the calculated learning value of each of the learning regions in a non-volatile storage device;
a forced learning canceling unit that cancels the forced learning mode when the forced learning value calculation/storage unit has completed calculation and storage of the learning values for each of the learning regions;
having
The internal combustion engine system includes:
An information output device capable of outputting instructions to a user is provided,
In the forced learning mode, the control device
the forced learning value calculation and storage unit uses the information output device to output to a user an instruction of an operation amount of the accelerator pedal that corresponds to an intake amount for each learning region , and calculates and stores the learning value for each learning region while allowing the user to change the intake amount of the internal combustion engine according to the operation amount of the accelerator pedal .
A control device for an internal combustion engine system. The control device for an internal combustion engine system according to claim 5 ,
The control device includes:
before starting the forced learning mode, the forced learning value calculation and storage unit selects, from the plurality of learning regions, a plurality of learning regions corresponding to an accelerator pedal depression amount, which is a depression amount of the accelerator pedal by a user .
A control device for an internal combustion engine system. The control device for an internal combustion engine system according to claim 5 or 6,
The control device includes:
a forced warm-up promotion unit that outputs a warm-up promotion instruction to a user using the information output device when it is determined that the warm-up of the internal combustion engine has not been completed before starting the forced learning mode,
In the case where the warm-up is promoted by the forced warm-up promotion unit, when the warm-up is completed, the promotion of the warm-up is terminated and the process proceeds to the forced learning value calculation and storage unit.
A control device for an internal combustion engine system.

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