JP7619196B2 - Control device for internal combustion engine - Google Patents

Description

This disclosure relates to a control device for an internal combustion engine, and in particular to a control device for a compression ignition type internal combustion engine.

Compression autoignition internal combustion engines, such as diesel engines, are known in which fuel injected into a combustion chamber from a fuel injection valve is burned by self-ignition. For example, Japanese Patent Application Laid-Open No. 11-159385 discloses a diesel engine that can reduce NOx (nitrogen oxides) and PM (particulate matter) by calculating a fuel injection period from detected values of fuel injection start and end times, calculating an ignition delay period from detected values of fuel injection start and combustion start times, and increasing and correcting the fuel injection pressure so that the fuel injection period is shortened when the ignition delay period is shorter than the fuel injection period.

Japanese Patent Application Publication No. 11-159385

When the amount of fuel injected from the fuel injection valve increases, the fuel injection period becomes longer. When the fuel injection period becomes longer, the injection end timing becomes more retarded in terms of the crank angle. When the injection end timing becomes more retarded, problems such as an increase in exhaust temperature and an increase in soot contamination of the lubricating oil occur.

Fuel injection valves have variations in their injection characteristics, and the injection characteristics change due to deterioration. For this reason, experiments are conducted in advance to determine the crank angle at which injection ends (limit injection end time) at which problems such as rising exhaust temperature and increased soot mixing into the lubricating oil begin to occur, and the fuel injection amount is set so that the injection end time falls within the limit injection end time (so that the injection end time is not retarded from the limit injection end time) while taking into account variations in and changes in the injection characteristics of the fuel injection valve.

In this way, the fuel injection amount is set taking into account the variation and change in the injection characteristics of the fuel injection valve, which limits the amount of fuel injection, resulting in a problem that the output of the internal combustion engine is lower than the output that should be obtained. Patent Document 1 does not disclose this point.

The purpose of this disclosure is to enable the output of an internal combustion engine to be increased while ensuring that the injection end timing falls within the limit injection end timing (so that the injection end timing is not retarded from the limit injection end timing).

The internal combustion engine control device disclosed herein is a control device for a compression autoignition type internal combustion engine having a fuel injection valve that injects fuel into a combustion chamber. The control device includes an injection end timing acquisition unit that acquires the injection end timing at which fuel injection by the fuel injection valve ends, and an injection amount calculation unit that reduces the fuel injection amount when the injection end timing is on the retard side of a predetermined crank angle.

According to this configuration, the injection amount calculation unit reduces the fuel injection amount when the injection end timing acquired by the injection end timing acquisition unit is more retarded than the specified crank angle. By acquiring the injection end timing and reducing the fuel injection amount when the acquired injection end timing is more retarded than the specified crank angle, it becomes possible to keep the injection end timing within the limit injection end timing (it becomes possible to prevent the injection end timing from being more retarded than the limit injection end timing) without setting the fuel injection amount by taking into account the variation and characteristic changes in the injection characteristics of the fuel injection valve, and the output of the internal combustion engine can be increased.

Preferably, the injection amount calculation unit may be configured to correct the basic injection amount calculated according to the load by decreasing it when the injection end timing is retarded from the specified crank angle.

With this configuration, it is possible to bring the injection end timing within the limit injection end timing by a simple method of reducing the basic injection amount.

Preferably, the injection amount calculation unit is configured to calculate the basic injection amount according to the load from a pre-stored map, and to reduce the fuel injection amount by rewriting the map when the injection end timing is retarded from the specified crank angle.

With this configuration, the fuel injection amount is reduced by rewriting the map that calculates the basic injection amount, so a map that takes into account changes in the characteristics of the fuel injection valve can be obtained.

Preferably, the predetermined crank angle may be a crank angle at which the amount of soot mixed into the lubricating oil becomes equal to or greater than a predetermined value when the injection end timing is retarded from the predetermined crank angle.

This configuration allows the fuel injection amount to be set large within a range that allows the injection end timing to fall within the limit injection end timing, thereby increasing the output of the internal combustion engine.

Preferably, the specified crank angle may be a crank angle that is advanced by a set crank angle from the crank angle at which soot mixing into the lubricating oil exceeds a specified value when the injection end timing is retarded from the specified crank angle.

With this configuration, the fuel injection amount is set with a margin of the set crank angle, so even if there is variation in the accuracy of the injection end timing acquisition unit, the injection end timing can be reliably set to the limit injection end timing.

According to the present disclosure, it is possible to increase the output of an internal combustion engine while ensuring that the injection end timing falls within the limit injection end timing.

1 is an overall configuration diagram of an internal combustion engine according to an embodiment of the present invention; 11 is a diagram showing the relationship between the injection end timing and the amount of soot mixed into the lubricating oil. FIG. 4 is a diagram showing the relationship between the fuel injection amount and the injection end timing when the internal combustion engine 1 is operating at full load. FIG. 3 is a flowchart showing a fuel injection control process executed by an E/G-ECU 100. 4 is a flowchart showing a correction amount calculation control process executed by an E/G-ECU 100. 4 is a diagram showing the relationship between the fuel injection amount and the injection end timing when the internal combustion engine 1 is operating at full load in the present embodiment. FIG. 10 is a flowchart showing a basic injection amount update control process executed by an E/G-ECU 100 in a modified example.

The following describes in detail the embodiments of the present disclosure with reference to the drawings. Note that the same or corresponding parts in the drawings are given the same reference numerals and their description will not be repeated.

Figure 1 is an overall configuration diagram of an internal combustion engine according to this embodiment. The internal combustion engine 1 is a diesel engine that injects fuel from a fuel injector 14 into a combustion chamber formed in a cylinder 12 of an engine body 10, and performs compression self-ignition. An air cleaner 22, an intercooler 24, and an intake throttle valve (electronically controlled throttle) 26 are provided in an intake passage 20 of the internal combustion engine 1. Fresh air from which foreign matter has been removed by the air cleaner 22 is supercharged (compressed) by a compressor 32 of a turbocharger 30, cooled by the intercooler 24, supplied to an intake manifold 28, and supplied to each combustion chamber from an intake port.

In this embodiment, the fuel injection system employs a common rail fuel injection system (accumulator type fuel injection device), in which fuel from a fuel tank 40 is supplied to a common rail 42 by a high-pressure pump 41, and the high-pressure fuel accumulated in the common rail 42 is injected into the combustion chamber from a fuel injection valve 14.

The fuel injection valve 14 is composed of a fuel injection nozzle that injects fuel into the combustion chamber, a piezoelectric element that drives a nozzle needle housed in the fuel injection nozzle in the valve opening direction, and a needle biasing means such as a spring that biases the nozzle needle in the valve closing direction, and fuel injection is controlled by energizing and de-energizing the piezoelectric element (ON/OFF). While the nozzle needle opens the multiple injection holes formed at the tip of the nozzle body by energizing the piezoelectric element, high-pressure fuel stored in the common rail 42 is injected into the combustion chamber. The fuel injection valve 14 is provided with a fuel pressure sensor 16 that detects the fuel pressure in the fuel passage from the common rail 42 to the injection hole. The nozzle needle may be opened by using an electromagnetic solenoid or the like.

Exhaust gas discharged from the combustion chamber is collected in an exhaust manifold 50 and released into the outside air via an exhaust passage 52. In the exhaust passage 52, from the upstream side, the turbine 34 of the turbocharger 30, an oxidation catalyst 70, a DPF (Diesel Particulate Filter) 72, a selective reduction catalyst 74, and an oxidation catalyst 76 are provided. The oxidation catalyst 70 oxidizes carbon monoxide (CO) in the exhaust gas to carbon dioxide (CO2), and oxidizes hydrocarbons (HC) in the exhaust gas to water ( _H2O ) and _CO2 . It also oxidizes nitrogen monoxide (NO) in the exhaust gas to nitrogen dioxide ( _NO2 ).

The DPF 72 collects particulate matter in the exhaust gas and purifies it by appropriately burning and removing the collected particulate matter. The selective reduction catalyst (hereinafter also referred to as the SCR (Selective Catalytic Reduction) catalyst) 74 reduces and purifies NOx in the exhaust gas. The oxidation catalyst 76 oxidizes and purifies ammonia discharged (slips) from the SCR catalyst 74.

A urea addition valve (urea water injection injector) 80 is provided in the exhaust passage upstream of the SCR catalyst 74, and urea water pressurized by a pump (not shown) from a urea water tank 82 is injected from the urea addition valve 80 into the exhaust passage 52 upstream of the SCR catalyst 74. The urea water supplied to the exhaust passage upstream of the SCR catalyst 72 is hydrolyzed to generate ammonia, and this ammonia is used as a reducing agent to reduce and purify NOx.

In this embodiment, the control device for the internal combustion engine 1 is an E/G-ECU (Electronic Control Unit) 100. The E/G-ECU 100 includes a CPU (Central Processing Unit) 101, a memory 102 such as a ROM (Read Only Memory) for storing processing programs and the like, a RAM (Random Access Memory) for temporarily storing data, and an input/output port (not shown) for inputting and outputting various signals, and executes predetermined arithmetic processing based on information stored in the memory (ROM and RAM) 102 and information from various sensors, to control the fuel injection valve 14, etc.

The various sensors include, for example, a fuel pressure sensor 16, an accelerator opening sensor 121, a crank angle sensor 122, and a coolant temperature sensor 123. The fuel pressure sensor 16 detects the fuel pressure P in the fuel passage from the common rail 42 to the injection hole. The accelerator opening sensor 121 detects the accelerator pedal operation amount (accelerator opening) AP. The crank angle sensor 122 detects the crank angle CA of the internal combustion engine 1. The coolant temperature sensor 123 detects the coolant temperature THW of the internal combustion engine 1.

When the fuel injection amount injected from the fuel injection valve 14 becomes larger, the fuel injection period (opening period of the fuel injection valve 14) becomes longer. When the fuel injection period becomes longer, the injection end time becomes the retarded side of the crank angle. FIG. 2 is a diagram showing the relationship between the injection end time and the amount of soot mixed into the lubricating oil. In FIG. 2, the horizontal axis is the injection end time, which indicates the crank angle (CA) after the top dead center (ATDC). The vertical axis is the soot concentration of the lubricating oil. As shown in FIG. 2, when the injection end time becomes retarded from the crank angle Cm, the soot concentration of the lubricating oil (the amount of soot in the oil) becomes larger. In addition, when the injection end time becomes retarded, the exhaust temperature also increases. The crank angle Cm at which the amount of soot in the oil starts to increase is also called the limit injection end time Cm.

Figure 3 is a diagram showing the relationship between the fuel injection amount and the injection end timing when the internal combustion engine 1 is operating at full load. In Figure 3, the upper part shows the injection command of the fuel injection valve 14. When the injection command is ON, electricity is applied to the piezoelectric element, the injection hole of the fuel injection valve 14 opens, and fuel is injected. In Figure 3, the lower part shows the injection rate of the fuel injection. In the example shown in Figure 3, two-stage injection is performed, pilot injection and main injection, and pilot injection is performed first, followed by main injection. When the injection command is ON and electricity is applied to the piezoelectric element, fuel is injected from the injection hole after an injection delay, and when the injection command is OFF and electricity is stopped, fuel injection stops with a delay. In the lower part of Figure 3, the area surrounded by the injection rate corresponds to the fuel injection amount.

The larger the fuel injection amount, the greater the output the internal combustion engine 1 can generate. Therefore, when the internal combustion engine 1 is operating at full load, such as at WOT (Wide Open Throttle), it is desirable to make the fuel injection amount as large as possible. However, there is variation in the injection characteristics of the fuel injection valve 14, and the injection characteristics change due to deterioration. For this reason, the margin A is set taking into account the variation and characteristic changes in the injection characteristics of the fuel injection valve 14, and the injection period (current application period) Tp is obtained so that the injection end timing is advanced by the margin A from the limit injection end timing Cm, and the fuel injection amount during full load operation is set. As a result, even if there is variation and characteristic changes in the injection characteristics of the fuel injection valve 14, the fuel injection amount can be set so that the injection end timing falls within the limit injection end timing Cm (so that the injection end timing is not retarded from the limit injection end timing Cm).

When the fuel injection amount is set in this manner, as shown in the shaded area in Figure 3, the fuel injection amount is limited by the fuel injection amount equivalent to the margin A, so the output of the internal combustion engine 1 during full load operation decreases and the performance of the internal combustion engine 1 cannot be effectively utilized.

In this embodiment, the injection end timing is obtained, and when the injection end timing is more retarded than the limit injection end timing Cm, the fuel injection amount is reduced so that the injection end timing falls within the limit injection end timing Cm (so that the injection end timing is not more retarded than the limit injection end timing Cm), while the output of the internal combustion engine 1 can be increased.

Figure 4 is a flowchart showing the fuel injection control process executed by the E/G-ECU 100. This flowchart is repeatedly processed during operation of the internal combustion engine 1 (from when the ignition switch is turned on until the ignition switch is turned off). In step (hereinafter, step is abbreviated as S) 10, it is determined whether the DPF 72 is being regenerated. During regeneration of the DPF 72, in which particulate matter captured by the DPF 72 is burned and removed, the fuel injection timing is retarded and exhaust stroke injection is performed, etc., to raise the exhaust temperature, so that the injection end timing is retarded from the limit injection end timing Cm. Therefore, if the DPF 72 is being regenerated and a positive determination is made in S10, the current routine is terminated. (In this case, a fuel injection control process for regenerating the DPF 72 is executed separately.) If the DPF 72 is not being regenerated, a negative determination is made and the routine proceeds to S11.

In S11, the number of injection stages is calculated based on the accelerator opening AP and the engine speed NE. The engine speed NE can be calculated based on the crank angle CA detected by the crank angle sensor 122.

In the next step S12, a basic injection amount Q is calculated based on the accelerator opening AP and the engine speed NE. The basic injection amount Q is stored in the memory 102 as a map with the accelerator opening AP and the engine speed NE as parameters. Note that if the number of injection stages and the basic injection amount are specified in an optimal injection map with the accelerator opening AP and the engine speed NE as parameters, steps S11 and S12 may be processed simultaneously.

In S13, the target injection amount Qf is calculated. For example, the target injection amount Qf is calculated as "target injection amount Qf = Q + Qt + Qa - Qh". Here, Qt is a warm-up correction amount, which is calculated based on the cooling water temperature THW. Qa is an acceleration correction amount, which is calculated based on the change amount ΔAP in the accelerator opening AP. Qh is an injection timing correction amount, which is calculated by the correction amount calculation control (Figure 5) described later. Note that after the internal combustion engine 1 has finished warming up, "warm-up correction amount Qt = 0" is set, and when the change amount ΔAP in the accelerator opening AP is equal to or less than a predetermined value, "acceleration correction amount Qa = 0" is set.

In the next step S14, the injection start time T is calculated based on the engine speed NE and the target injection amount Qf. Then, in step S15, the injection period (energization period) Tp is calculated based on the fuel pressure Pc in the common rail 42, the engine speed NE, and the target injection amount Qf, and the current routine is terminated.

When the injection start time T and injection period Tp are calculated by the fuel injection control process, the injection command is ON from the injection start time T until the end of the injection period Tp. As a result, while the injection command is ON, electricity is applied to the actuator (piezoelectric element, etc.) for the fuel injection valve 14 via the injection valve drive circuit (not shown), and fuel is injected from the fuel injection valve 14. Note that the injection start time T and injection period Tp are calculated for each injection stage, and the number of injection stages calculated in S11 may include (as information) the distribution rate of the target injection amount Qf to each injection stage.

In S12, the basic injection amount Q is calculated based on the accelerator opening AP and the engine speed NE, but the basic injection amount Q may also be calculated by so-called torque demand control. For example, the required shaft torque may be calculated from the accelerator opening AP and the engine speed NE, and the required indicated torque (combustion pressure torque) may be obtained by adding the consumed torque of the internal combustion engine 1 to this required shaft torque, and the basic injection amount Q may be calculated based on this required indicated torque. In either case, the basic injection amount Q is calculated according to the load on the internal combustion engine 1.

Figure 5 is a flowchart showing the correction amount calculation control process executed by the E/G-ECU 100. This flowchart is repeatedly processed while the internal combustion engine 1 is in operation. In S20, it is determined whether the DPF 72 is being regenerated. If the DPF 72 is being regenerated, a positive determination is made and the current routine is terminated. If the DPF 72 is not being regenerated, a negative determination is made and the routine proceeds to S21.

In S21, the injection end time Te is acquired. In this embodiment, the injection end time Te is calculated using the fuel pressure P in the fuel passage from the common rail 42 to the injection hole, detected by the fuel pressure sensor 16. For example, when the fuel pressure P increases with the injection command being OFF, the injection end time Te is calculated based on the timing at which the derivative value of the fuel pressure P becomes maximum. Note that the method of calculating the injection end time Te using the derivative value of the fuel pressure P is publicly known, and therefore a detailed description thereof will be omitted. (For example, see JP 2019-65721 A.)
In the next step S22, it is determined whether the injection end time Te obtained in step S21 is equal to or greater than a predetermined crank angle Tcm. In this embodiment, the injection end time Te obtained in step S21 is obtained as the value of the crank angle CA at ATDC. If the injection end time Te is greater than the predetermined crank angle Tcm, the injection end time Te is retarded from the predetermined crank angle Tcm. The predetermined crank angle Tcm is a value advanced from the limit injection end time Cm by a margin a. The margin a is set, for example, taking into consideration the calculation variation of the injection end time Te, and is set in advance by experiment or the like as a value smaller than the margin A in FIG. 3.

If the injection end time Te is equal to or greater than the specified crank angle Tcm and is retarded by the specified crank angle Tcm or more, a positive judgment is made in S22 and the process proceeds to S23. If the injection end time Te is less than the specified crank angle Tcm and is advanced from the specified crank angle Tcm, a negative judgment is made in S22 and the process proceeds to S24.

In S23, a predetermined value α is added to the injection timing correction amount Qh, and the current routine ends. In S24, it is determined whether the injection timing correction amount Qh is equal to or less than 0. In S24, if the injection timing correction amount Qh is greater than 0, a negative determination is made and the process proceeds to S15, and if the injection timing correction amount Qh is equal to or less than 0, a positive determination is made and the process proceeds to S26.

In S25, a predetermined value β is subtracted from the injection timing correction amount Qh, and the current routine ends. In S26, the injection timing correction amount Qh is set to 0, and the current routine ends.

In this embodiment, in the correction amount calculation control, when the injection end time Te is more retarded than the specified crank angle Tcm, the injection timing correction amount Qh is calculated to be large (S23). Then, in the fuel injection control, the target injection amount Qf is calculated by subtracting the injection timing correction amount Qh from the basic injection amount Q (S13). Therefore, when the injection end time Te is more retarded than the specified crank angle Tcm, the target injection amount Qf decreases and the injection period Tp becomes shorter. Then, when the injection period Tp becomes shorter and the injection end time Te is more advanced than the specified crank angle Tcm, the injection timing correction amount Qh is calculated to be small and is finally set to 0 (S24 to S26).

Figure 6 is a diagram showing the relationship between the fuel injection amount and the injection end time during full load operation of the internal combustion engine 1 in this embodiment. In Figure 6, the upper part shows the injection command of the fuel injection valve 14, and the lower part shows the injection rate of the fuel injection. In this embodiment, when the injection end time Te becomes more retarded than the specified crank angle Tcm, the target injection amount Qf is reduced to control the injection period Tp to be shorter. Therefore, as shown in Figure 6, even if the margin a is set smaller than the margin A (see Figure 3) that takes into account the variation and characteristic change of the injection characteristics of the fuel injection valve 14 and the specified crank angle Tcm is set, the injection end time Te can be kept within the limit injection end time Cm (the injection end time can be prevented from becoming more retarded than the limit injection end time Cm). Therefore, even if the fuel injection amount is set without taking into account the variation and change in the injection characteristics of the fuel injection valve 14, it is sufficient to limit the fuel injection amount by the fuel injection amount equivalent to the margin a (see the shaded area in Figure 6), and since the fuel injection amount can be increased compared to the conventional method, the output of the internal combustion engine 1 can be increased and the performance of the internal combustion engine 1 can be effectively utilized.

In the above embodiment, the allowance a was set taking into consideration the calculation variation of the injection end timing Te. However, if the calculation accuracy of the injection end timing Te is high, the allowance a may be set to 0 (the allowance a may not be necessary). For example, if a stroke sensor (displacement sensor) is provided on the nozzle needle of the fuel injection valve 14 and a configuration is made that can detect when the nozzle needle closes the injection hole, the injection end timing Te can be detected with high accuracy. In this case, the allowance a may be set to 0 and the predetermined crank angle Tcm may be set as the limit injection end timing Cm. Even in this case, the predetermined crank angle Tcm may be set using a allowance smaller than the allowance a, taking into consideration the control variation of the fuel injection control.

(Modification)
In the above embodiment, the target injection amount Qf is obtained by calculating the injection timing correction amount Qh and correcting the basic injection amount Q by decreasing it. However, the configuration for decreasing the fuel injection amount (target injection amount Qf) is not limited to this.

Figure 7 is a flowchart showing the processing of the basic injection amount update control executed by the E/G-ECU 100 in the modified example. This flowchart is processed repeatedly while the internal combustion engine 1 is in operation. In S30, it is determined whether or not the DPF 72 is being regenerated. If the DPF 72 is being regenerated, a positive determination is made and the current routine is terminated. If the DPF 72 is not being regenerated, a negative determination is made and the routine proceeds to S31.

In S31, similar to S21 in FIG. 6, the injection end time Te is acquired, and then the routine proceeds to S32. In S32, it is determined whether the injection end time Te is equal to or greater than a predetermined crank angle Tcm. If the injection end time Te is less than the predetermined crank angle Tcm and is more advanced than the predetermined crank angle Tcm, a negative determination is made in S32, and the current routine is terminated.

If the injection end time Te is equal to or greater than the predetermined crank angle Tcm and is retarded by more than the predetermined crank angle Tcm, a positive determination is made in S32 and the process proceeds to S33. In S33, a new basic injection amount Q is calculated by subtracting a predetermined value γ from the basic injection amount Q for the fuel injection at the injection end time Te obtained in S31. Then, in the map for calculating the basic injection amount, the corresponding value of the basic injection amount Q is rewritten to the new value of the basic injection amount Q, the map is updated, and the current routine is terminated.

In this modified example, fuel injection is performed from the fuel injection valve 14 using the fuel injection control shown in FIG. 4. In this modified example, the injection timing correction amount Qh is not calculated, so in S13, the target injection amount Qf is calculated as "Qf = Q + Qt + Qa."

According to this modification, when the injection end time Te is on the retard side of the predetermined crank angle Tcm , the corresponding value of the basic injection amount Q in the map for calculating the basic injection amount is rewritten to a new basic injection amount Q, so that the basic injection amount Q becomes a small value. Therefore, when the injection end time Te becomes on the retard side of the predetermined crank angle Tcm, the target injection amount Qf is decreased and the injection period Tp is controlled to be shortened, and the same effect as that of the above embodiment is achieved. In addition, the value of the basic injection amount Q when the injection end time Te becomes on the retard side of the predetermined crank angle Tcm or more is rewritten to a small value and the map is updated, so that a map that takes into account the change in the characteristics of the fuel injection valve 14 can be obtained. Since the basic injection amount Q is calculated using the updated map, it is possible to prevent the injection end time Te from becoming on the retard side of the predetermined crank angle Tcm .

In the above embodiment and modified example, when the DPF 72 is not being regenerated, it is determined whether the injection end time Te is on the retard side of the predetermined crank angle Tcm , and a correction such as a reduction in the fuel injection amount is performed. The injection end time Te is on the retard side of the predetermined crank angle Tcm only when the load on the internal combustion engine 1 is large and the fuel injection amount is large. Therefore, in addition to the condition that the DPF 72 is not being regenerated, when the load on the internal combustion engine 1 is high, for example, when the condition "when the accelerator opening AP is a predetermined value (for example, 90%) or more" is satisfied, it may be determined whether the injection end time Te is on the retard side of the predetermined crank angle Tcm .

The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims rather than by the description of the embodiments above, and is intended to include all modifications within the meaning and scope of the claims.

1 internal combustion engine, 10 engine body, 12 cylinder, 14 fuel injection valve, 16 fuel pressure sensor, 20 intake passage, 22 air cleaner, 24 intercooler, 26 intake throttle valve, 28 intake manifold, 30 turbocharger, 32 compressor, 34 turbine, 40 fuel tank, 41 high pressure pump, 42 common rail, 50 exhaust manifold, 52 exhaust passage, 54 bypass passage, 70 oxidation catalyst, 72 DPF, 74 selective reduction catalyst (SCR catalyst), 76 oxidation catalyst, 80 urea addition valve, 82 urea water tank, 100 E/G-ECU, 101 CPU, 102 memory, 121 accelerator opening sensor, 122 crank angle sensor, 123 cooling water temperature sensor.

Claims (2)

A control device for a multi-cylinder compression ignition type internal combustion engine having a fuel injection valve that injects fuel into a combustion chamber,
The control device includes:
an injection end timing acquisition unit that acquires an injection end timing at which fuel injection by the fuel injection valve is ended;
an injection amount calculation unit that reduces a fuel injection amount when the injection end timing is retarded from a predetermined crank angle,
the injection amount calculation unit calculates a basic injection amount according to a load from a pre-stored map, and when the injection end timing is on the retard side of the predetermined crank angle, calculates a new basic injection amount by subtracting a predetermined value from the calculated basic injection amount, rewrites a corresponding value of the basic injection amount in the map to the new basic injection amount, and updates the map, thereby reducing the fuel injection amount ;
A control device for an internal combustion engine , wherein the specified crank angle is a crank angle at which soot mixing into lubricating oil becomes equal to or exceeds a specified value when the injection end timing becomes more retarded than the specified crank angle . A control device for a multi-cylinder compression ignition type internal combustion engine having a fuel injection valve that injects fuel into a combustion chamber,
The control device includes:
an injection end timing acquisition unit that acquires an injection end timing at which fuel injection by the fuel injection valve is ended;
an injection amount calculation unit that reduces a fuel injection amount when the injection end timing is retarded from a predetermined crank angle,
the injection amount calculation unit calculates a basic injection amount according to a load from a pre-stored map, and when the injection end timing is on the retard side of the predetermined crank angle, calculates a new basic injection amount by subtracting a predetermined value from the calculated basic injection amount, rewrites a corresponding value of the basic injection amount in the map to the new basic injection amount, and updates the map, thereby reducing the fuel injection amount;
A control device for an internal combustion engine, wherein the specified crank angle is a crank angle that is advanced by a set crank angle from the crank angle at which soot mixing into the lubricating oil exceeds a specified value when the injection end timing is retarded from the specified crank angle .

Images