JPH0774622B2 - Engine controller - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention electrically detects, for example, an operation amount of an accelerator operated by a driver, and an electric actuator for a throttle valve provided in an engine according to the operation amount. The present invention relates to an engine control device in an engine having an electric control type throttle valve control device which is controlled by.

[Conventional technology]

Conventionally, a throttle valve provided in a vehicle engine has been directly connected to an accelerator pedal through a link mechanism, and has been mechanically driven according to the amount of depression of the accelerator pedal by a driver.

In recent years, many devices have been proposed that electrically detect the accelerator operation amount and control the opening of the throttle valve by an electric actuator such as a motor according to the detected accelerator operation amount.

In the electrically controlled throttle valve control devices disclosed in Japanese Patent Laid-Open No. 61-8435, Japanese Patent Laid-Open No. 61-8436 and Japanese Patent Laid-Open No. 61-8437, the drive system and control system of the throttle valve are The controller determines an abnormality, for example, when the motor or the throttle valve locks up and does not move, or the throttle valve does not close due to a partial failure of the controller.

[Problems to be solved by the invention]

However, the entire drive system and control system of the throttle valve, including the controller, may become abnormal, but in the technique disclosed in the above publication, the controller performs the abnormality determination, so the controller has completely failed. In this case, for example, when the failure determination capability is lost due to a program runaway or power failure, there is a problem that the fail-safe function does not work and there is nothing to do.

Therefore, an object of the present invention is to provide an engine having an electrically controlled throttle valve control state, even if all of the throttle valve drive system and the control system become abnormal and the failsafe function does not work in the throttle valve control system. A fail-safe function of a fuel system ensures safety and provides a highly reliable engine control device.

[Means for solving problems]

In order to solve the above problems, the present invention provides a seventh
As shown in the figure, a throttle valve that adjusts the amount of air taken into the engine, an actuator that drives the throttle valve, an operation amount detection unit that detects an accelerator operation amount of an accelerator operated by a driver, and the operation A target opening setting means for setting a target opening of the throttle valve according to the accelerator operation amount detected by the amount detecting means; and a drive signal according to the target opening set by the target opening means. A drive signal output means for outputting to the actuator, an operating state detecting means for detecting an operating state of the engine which changes according to an actual opening degree of the throttle valve, and an operating state detected by the operating state detecting means. And a fuel supply amount calculating means for calculating the fuel supply amount to the engine based on the fuel supply amount calculating means when the throttle valve is normally driven. Limit setting means for setting at least one of the upper limit and the lower limit in the range of the fuel supply amount that can be set according to the accelerator operation amount, and the fuel supply amount and the limit obtained by the fuel supply amount calculation means. When the fuel supply amount exceeds the limit by comparing the fuel supply amount with the limit set by the setting device, the fuel supply amount is limited to the limit by the limiting device and the limiting device. And a fuel supply unit that supplies the fuel supply amount to the engine.

[Action]

According to the above configuration, when an abnormality occurs in the throttle control system and the consistency between the accelerator operation amount and the actual throttle valve opening cannot be obtained, the operating state parameter (for example, the intake Amount) will increase or decrease compared to when the throttle system is normal, so
As a result, the fuel supply amount tends to be calculated to increase or decrease, but the limit setting means sets the limit range of the fuel supply amount on the assumption that the throttle valve is normally driven according to the accelerator operation amount. Since the fuel is supplied after that, when the throttle valve is abnormal, the air-fuel ratio of the air-fuel mixture supplied to the engine largely deviates from the proper state, so that the torque generated in the engine decreases.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram showing a schematic configuration of the present embodiment. An engine 1 is a spark ignition type four-cylinder engine mounted on a vehicle. The engine 1 includes an intake pipe 2 and an exhaust pipe 3. It is connected.

The intake pipe 2 is composed of a collecting pipe 2a, a surge tank 2b, and a branch pipe 2c that branches corresponding to each cylinder of the engine 1. An air cleaner (not shown) is provided on the most upstream side of the collecting pipe 2a of the intake pipe 2, and a throttle valve 4 for adjusting the amount of air taken into the engine 1 is provided on the downstream side thereof. An intake air temperature sensor 5 that detects the intake air temperature is provided between the air cleaner and the throttle valve 4. Further, on the outer peripheral wall of the collecting pipe 2a, there is provided a reversible motor 6 which constitutes a throttle valve driving actuator having a rotor connected to the rotary shaft of the throttle valve 4. The motor 6 is, for example, a step motor or a step motor. It consists of a DC motor. At the other end of the rotary shaft of the throttle valve 4, a spring 4a for urging the throttle valve 4 in the fully closing direction is provided.
And an opening sensor 7 for detecting the actual opening of the throttle valve 4 that outputs an analog signal according to the opening of the throttle valve 4.

An intake pressure sensor 8 for detecting the intake pressure in the surge tank is connected to the surge tank 2b.
An electromagnetically operated injection valve 9 for injecting fuel is provided near the intake valve (not shown) of the engine 1 at 2c.

The exhaust pipe 3 is provided with an air-fuel ratio sensor 10 for detecting the air-fuel ratio from the residual oxygen concentration in the exhaust gas.

The engine 1 is provided with a water temperature sensor 11 for detecting the temperature of cooling water for engine cooling and an ignition plug 16.

The spark plug 16 is connected to the distributor 17, and the high voltage generated by the igniter 18 is applied to the spark plug 16 via the distributor 17.

The distributor 17 is provided with a rotation sensor 12 and generates a pulse signal according to the rotation speed of the engine 1.

Reference numeral 20 is a throttle controller for controlling the opening degree of the throttle valve 4 whose main part is composed of a microcomputer, and inputs an engine operating state signal from each of the above sensors and outputs a drive signal to the motor 6. . In addition to the above sensors, the throttle controller 20 receives a signal corresponding to the operation amount from an accelerator sensor 13 connected to an accelerator pedal 13a operated by a driver.

Similar to the throttle controller 20, a reference numeral 30 is an engine controller which is mainly composed of a microcomputer for engine control, and particularly for executing fuel injection control and ignition timing control. The engine operating state signal from each sensor is input to this engine controller 30 as well as the signal from the accelerator sensor 13.

In addition, 14 is a battery, and the throttle controller 20
And supplying power to the engine controller 30. By the way, an IG switch 15 operated by a driver is provided in the middle of an energization line from the battery 14 to each controller 20, 30.

The main structure of the throttle controller 20 is shown in FIG. 21 is the intake temperature sensor 5, the opening sensor 7, the intake pressure sensor
8, a CPU that performs throttle valve control including the drive amount of the motor 6 based on signals from the water temperature sensor 11, the rotation sensor 12, and the accelerator sensor 13. 22 is a ROM, which is a read-only memory that stores constants and data used in the processing of the CPU 21, and 23 is a temporary storage of the calculation results obtained by the CPU 21, the detection data from the above sensors, etc. RAM, which is a writable memory. RAM
The memory 23 is configured to retain its memory contents even when power supply to the throttle controller 20 is lost. An input unit 24 receives signals from each sensor and performs signal processing such as A / D conversion and waveform shaping on these signals. 25 is an output unit, CPU2
A signal for driving the motor 6 is output based on the processing result executed in 1. 26 is a common bus, CP
U21, ROM22, RAM23, input unit 24, output unit 25 are connected to each other and used for mutual data transmission. 27 is a power supply circuit, which is connected to the battery 14 via the IG switch 15, and the CPU 21,
Power is supplied to the ROM 22, the RAM 23, the input unit 24, and the output unit 25.

FIG. 3 shows the main configuration of the engine controller 30. As with the throttle controller 20, the CPU 31,
It is composed of a ROM 32, a RAM 33, an input unit 34, an output unit 35, a common bus 36, and a power supply circuit 37. And this engine controller 30 inputs signals from the intake air temperature sensor 5, the opening sensor 7, the intake pressure sensor 8, the air-fuel ratio sensor 10, the water temperature sensor 11, the rotation sensor 12, and the accelerator sensor 13 via the input unit 34, Calculation of fuel injection amount, ignition timing, etc. is executed in the CPU 31 based on each signal, and the injection valve 9 ..., Igniter 18 is output via the output unit 35.
The drive signal is output to.

FIG. 4 shows a flow chart of a program relating to throttle valve opening control executed as a main routine by the CPU 21 of the throttle controller 20.

In FIG. 4, when the IG switch 15 is turned on and electric power is supplied to the throttle controller 20, the processing of this main routine is started.
Data of a predetermined address in 23 and initialization of the input unit 24 and the output unit 25 are executed. In step 402, intake air temperature T _A , actual throttle opening θ _S , intake air pressure P _m , water temperature T _W , rotation speed N _e , accelerator operation amount θ _A are fetched. In step 403, the accelerator operation amount θ _A
The basic target opening θ _SO of the throttle valve 4 based on
In addition to reading from the basic target opening map stored in, the correction value is obtained based on each of the other signals, and the basic target opening θ _SO is corrected by this correction value to calculate the current target opening θ _SS . In step 404, the current control amount D _S is read from the control amount map stored in the ROM 22 based on the target opening θ _SS . In step 405, the control amount D _S obtained through the above steps is output to the output unit 25. When the processing in step 405 is completed, the process returns to step 402 again.

Through the above processing, the output unit 25 forms a signal for driving the throttle valve 4 according to the control amount D _S , and then outputs this drive signal to the motor 6. Then, the motor 6 rotationally drives the throttle valve 4 based on the drive signal, so that the throttle valve 4 operates the accelerator pedal 13 operated by the driver.
The optimum opening degree is adjusted according to the accelerator operation amount θ _A and the engine state at that time.

FIG. 5 shows a flowchart of a program relating to the calculation of the fuel injection amount (fuel injection time) executed by the CPU 31 of the engine controller 30 as an interrupt routine. This interrupt routine is executed every 50 ms, for example. To be executed.

Referring to FIG. 5, in step 501, each data (intake pressure P _m , rotational speed N _e , intake temperature T _A necessary for calculating the fuel injection time, which is stored in the RAM 33 in advance, is directly stored in the RAM 33. , Throttle opening θ _S , air-fuel ratio signal S _{A / F} , water temperature T _W , accelerator operation amount θ _A ) are taken in.

The rotation speed N _e is obtained by calculating the reciprocal of the interrupt cycle in a rotation speed calculation routine (not shown) that is executed by interruption in synchronization with the pulse signal from the rotation sensor 12, and is sequentially stored in the RAM 33. It is stored.

Next, at step 502, the basic injection time T _p is obtained based on the intake pressure P _m and the rotation speed N _e . The basic injection time T _p is set according to the intake pressure and the rotation speed and is stored in the ROM 32 as a preliminary map, and is read from the map based on the intake pressure P _m and the rotation speed N _e at that time. Required by

Next, in steps 503 and 504, the upper limit value T _PMAX and the lower limit value T _{P with} respect to the basic injection time T _P are based on the accelerator operation amount θ _{A.
Find PMIN} . The upper limit value T _PMAX and the lower limit value T
_PMIN is the accelerator operation amount θ as described above when the control system and drive system for the throttle valve 4 are operating normally.
_{Since A} and the opening of the throttle valve 4 are controlled in a fixed relationship, and the basic injection time T _p has a substantially constant relationship with the opening of the throttle valve 4, the accelerator operation amount θ _A A control system of the throttle valve 4 which is opened and closed according to
The basic injection time T _p when the drive system is normal is set as shown in FIG. 6 with consideration given to the rotational speed and fluctuations during transient times such as acceleration / deceleration, and a predetermined allowable range is further added.

Then compared with the basic injection time T _p obtained by the upper limit value T _PMAX and the lower limit value T _PMIN and step 502 set in step 505 to 508 in step 503, the basic injection time T _p is the upper limit value T _PMAX , Or the lower limit value T _PMIN is _exceeded , the basic injection time T _p is set to the upper limit value T _PMAX or the lower limit value T _PMIN.
Restricted to.

In step 506, the intake air temperature T _A , the water temperature T _W, and the throttle opening θ
_The correction amount F _C is obtained from _S and the air-fuel ratio signal S _{A / F,} and step 5
At 07, the invalid injection time T _V is calculated based on the battery voltage. Then, in step 508, the basic injection time T _p obtained through the above steps is corrected by multiplication with the correction amount F _C , and the invalid injection time T _V is subjected to additive correction to obtain the output injection time T _O. Then, in step 509, the output injection time T _O thus obtained is stored in the RAM 33, and this routine ends.

The output injection time T _O obtained as described above is output to the output unit 35 by the fuel injection execution routine that is executed periodically in unillustrated engine rotation, and the output unit 35 responds to this signal by the injection valve 9 A pulsed drive signal having a time width corresponding to the output injection time T _O is output to. Then, the injection valve 9 is opened in response to this drive signal, and a predetermined amount of fuel is injected into each branch pipe 2c.

Regarding the ignition timing control, a drive signal formed based on the calculation result in the CPU 31 is output to the igniter 18 through the output unit 35 by a conventionally known means.

Meanwhile, according to the above configuration, the upper limit value T _PMAX of the basic injection time T _p in accordance with the accelerator operation amount theta _A of the accelerator pedal 13a is operated by the driver to set the lower limit value T _PMIN, a basic injection time T _p Since the upper limit value T _PMAX and the lower limit value T _PMIN are limited, the control system for the throttle valve 4 including the throttle controller 20 and the drive system become completely abnormal, and the throttle controller 20 cannot handle the situation. Even so, since the air-fuel ratio of the air-fuel mixture supplied to the engine 1 is out of the range of the combustible air-fuel ratio (8 to 20), the engine torque decreases and the vehicle speed automatically decreases.

For example, if the driver operates the accelerator pedal 13a so that the throttle valve 4 is in a half-open state for the purpose of medium-speed operation, and some abnormality occurs and the throttle valve 4 suddenly opens fully, the engine controller 30 Although more air is inhaled into the engine than predicted by the accelerator operation amount θ _A , the basic injection time T _p is equal to the accelerator operation amount θ _A.
The air-fuel ratio of the air-fuel mixture supplied to the engine 1 deviates from the stoichiometric air-fuel ratio to the lean side, and the torque decreases because the air-fuel ratio is limited by the upper limit value T _PMAX due to _A and does not correspond to the air that is actually taken in. On the contrary, when the throttle valve 4 is fully closed, the fuel injection time T _p is limited by the lower limit value T _PMIN by the accelerator operation amount θ _A , and the air-fuel ratio of the air-fuel mixture supplied to the engine 1 is more than the theoretical air-fuel ratio. Also greatly shifts to the rich side, and the torque also drops.

Therefore, according to the configuration of this embodiment, the throttle controller
Even if an abnormality occurs in the control system and drive system of the throttle valve 4 including 20, the vehicle speed is automatically reduced by the fail-safe mechanism according to the accelerator operation amount θ _A by the fuel system, ensuring excellent safety. The excellent effect of being extremely improved in terms of reliability is exhibited.

Although the basic injection time T _p is limited by the upper limit value T _PMAX and the lower limit value T _PMIN set by the accelerator operation amount θ _A in the above embodiment, the output injection time T _o or the basic injection time T Effective injection time T _I obtained by correcting _p with the correction amount F _c (=
T _p × F _c ) may be limited by the upper limit value and the lower limit value set by the accelerator operation amount θ _A. The upper limit value and the lower limit value when limiting the effective injection time T _I are the same as the upper limit value T _PMAX and the lower limit value T _PMIN for the basic injection time T _{p in} consideration of the fluctuation of the correction amount F _c. Is set.
Also the upper limit value and the lower limit value when performing the restriction on the output injection time T _o, is set in consideration of further variation of the ineffective injection time T _v.

Further, when the effective injection time T _I and the output injection time T _o are limited as described above, if the upper limit value and the lower limit value are corrected by the water temperature T _w and the intake air temperature T _A , higher controllability can be obtained. Will be obtained.

Further, in the above embodiment, the upper limit value and the lower limit value are set over the entire range of the accelerator operation amount θ _A from 0 to FULL, but the above-mentioned configuration causes the throttle valve 4 to be abnormal when the accelerator operation amount θ _A is small. Since it is particularly effective in the opened state, only the upper limit value of the injection time may be set when the accelerator operation amount θ _A is less than or equal to a predetermined value (for example, less than half of the total operation range). I don't care.

Further, in the above embodiment, the throttle controller 20 and the engine controller 30 are shown as separate blocks, but if they are configured to function independently of each other,
It does not matter if they are housed in the same package.

Further, the present invention can be applied not only to an electronically controlled fuel injection device but also to an electronically controlled carburetor.

In the above embodiment, the throttle controller 20 obtains the target opening θ _SS of the throttle valve 4 from the signals from the respective sensors, determines the control amount D _S according to the target opening θ _SS , and determines the control amount D _S By giving a drive signal according to
Although the opening of the throttle valve 4 was controlled, the target opening θ _SS of the throttle valve 4 was determined from the signal from each sensor, and the deviation from the throttle opening θ _S from the opening sensor 7 was calculated. The control variable D _S is integrated based on
Feedback control may be performed by giving a drive signal corresponding to D _S to the motor 6.

In the above embodiment, the rotation of the motor 6 is transmitted to the shaft of the throttle valve 4 to adjust the opening of the throttle valve 4. However, as shown in Japanese Patent Laid-Open No. 59-20539, the motor 6 is controlled by the ECU 20. The throttle valve 4 may have a rod that moves forward and backward in response to a drive signal from the lever, and the throttle valve 4 may be provided with a lever portion that abuts on the rod so that the opening of the throttle valve 4 can be adjusted by the movement of the rod. .

〔The invention's effect〕

As described above, according to the present invention, even if the control system and the drive system of the throttle valve become completely abnormal and the fail-safe function of the control system of the worst throttle valve does not work, the limit is limited. Since the fuel supply amount to the engine is limited by the limiting device by the limit set according to the accelerator operation amount by the setting device, the air-fuel ratio of the air-fuel mixture supplied to the engine largely deviates from the combustible range. , Because the engine torque will decrease,
There is an excellent effect that the safety is sufficiently ensured and high reliability is obtained.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing the configuration of an embodiment of the present invention, and FIG.
1 is a block diagram showing the configuration of the throttle controller of FIG. 1, FIG. 3 is a block diagram showing the configuration of the engine controller of FIG. 1, and FIG. 4 is a program executed by the CPU of the throttle controller of FIG. FIG. 5, FIG. 5 is a flowchart of a program executed by the CPU of the engine controller of FIG. 3, and FIG. 6 is a characteristic diagram showing the relationship between the accelerator operation amount θ _A and the upper limit value T _PMAX and the lower limit value T _PMIN . FIG. 7 is a block diagram showing a schematic configuration of the present invention. 1 …… Engine, 2 …… Intake pipe, 4 …… Throttle valve, 6 ……
Motor, 7 …… Opening sensor, 8 …… Intake pressure sensor, 9 …… Injection valve, 11 …… Water temperature sensor, 12 …… Rotation sensor, 13 …… Accelerator sensor, 20 …… Throttle controller, 30 …… Engine Controller, 21, 31 …… CPU, 22,32 …… ROM, 23,33 ……
RAM.

Claims (1)

[Claims] 1. A throttle valve for adjusting an amount of air taken into an engine, an actuator for driving the throttle valve, an operation amount detecting means for detecting an accelerator operation amount of an accelerator operated by a driver, and the operation. Target opening degree setting means for setting a target opening degree of the throttle valve according to the accelerator operation amount detected by the amount detecting means, and a drive signal according to the target opening degree set by the target opening degree setting means Drive signal output means for outputting to the actuator, an operating state detecting means for detecting an operating state of the engine which changes according to an actual opening degree of the throttle valve, and an operating state detected by the operating state detecting means. Fuel supply amount calculating means for calculating the fuel supply amount to the engine based on the above, and the fuel supply amount calculating means for calculating the fuel supply amount when the throttle valve is normally driven. Limit setting means for setting at least one of an upper limit and a lower limit in the range of the fuel supply amount that can be issued according to the accelerator operation amount, the fuel supply amount obtained by the fuel supply amount calculating means, and the fuel supply amount When the fuel supply amount exceeds the limit by comparing with the limit set by the limit setting means, the limiting means for limiting the fuel supply amount to the limit, and the limiting means And a fuel supply means for supplying the supplied fuel supply amount to the engine.