JP2021116703A - Control device for vehicle - Google Patents

Abstract

To appropriately prevent behavior of a vehicle from moving jerky due to low-speed operation in a half-clutch state.SOLUTION: A control device for a vehicle starts a fuel cut for stopping fuel supply to a cylinder on the condition that an amount of depression of an accelerator pedal by a driver becomes zero or less than a threshold close to zero and an amount of depression of a clutch pedal by the driver becomes a fuel cut determination value or more. The control device terminates the fuel cut and resumes fuel supply to the cylinder on the condition that the amount of depression of the accelerator pedal becomes larger than zero or the threshold close to zero or an engine rotation speed becomes a return rotation speed or less. The control device terminates the fuel cut and resumes fuel supply to the cylinder when even after passage of a predetermined time from start of the fuel cut, the amount of depression of the clutch pedal does not become a half-clutch determination value or more, which is higher than the fuel cut determination value, and further prohibits second execution of the fuel cut until the predetermined time passes.SELECTED DRAWING: Figure 3

Description

The present invention relates to the control of a traveling vehicle by transmitting the engine torque output by an internal combustion engine to the drive wheels via a clutch and a manual transmission.

In an MT (Manual Transmission) vehicle equipped with a manual transmission (see, for example, the following patent documents), the driver can arbitrarily operate the shift lever to change the shift position of the manual transmission. The driver can arbitrarily operate the clutch pedal to switch between engagement and disengagement of the clutch interposed between the internal combustion engine and the manual transmission.

When the driver of the MT vehicle shifts up the shift stage of the manual transmission, the amount of intake air and the amount of fuel injected into the cylinder of the internal combustion engine decrease, and the engine rotation slows down. During this transition period, the combustion of the air-fuel mixture in the combustion chamber of the cylinder becomes unstable, and the harmful substance HC is easily discharged.

Therefore, conventionally, the fuel supply to the cylinder is temporarily suspended on the condition that the amount of depression of the accelerator pedal by the driver is 0 or less than the threshold value close to 0 and the amount of depression of the clutch pedal is equal to or more than the fuel cut determination value. The fuel cut that is suspended is carried out to suppress the increase in the emission of harmful substance HC. This fuel cut ends on the condition that the amount of depression of the accelerator pedal becomes larger than 0 or a threshold value close to 0, or the engine speed becomes equal to or less than the return speed.

Japanese Unexamined Patent Publication No. 2018-168819

When the road is congested, the driver may step on the accelerator pedal little by little while depressing the clutch pedal sufficiently to engage in a slip-friction state without completely disengaging the clutch. You may repeatedly take your foot off the accelerator pedal. Then, as shown in FIG. 5, the fuel cut execution condition and the fuel cut end condition may be alternately satisfied within a short period of time, and the fuel cut and the return from the fuel cut may be repeated. As a result, the increase / decrease fluctuation of the engine torque and the number of revolutions becomes large, and the behavior of the vehicle may become jerky.

The present invention is intended to appropriately avoid the problem that the behavior of the vehicle is jerky due to low-speed operation in the half-clutch state.

The present invention is a control device that controls a traveling vehicle by transmitting engine torque output from an internal combustion engine to drive wheels via a clutch and a manual transmission, and the amount of depression of the accelerator pedal by the driver is set to 0 or 0. On condition that the pressure is below a close threshold and the amount of depression of the clutch pedal by the driver is equal to or greater than the fuel cut judgment value, fuel cut is started to stop the fuel supply to the cylinder, and the amount of depression of the accelerator pedal is 0 or The fuel cut is completed and the fuel supply to the cylinder is restarted on the condition that the engine speed becomes larger than the threshold value close to 0 or the engine speed becomes equal to or less than the return speed. If the amount of depression of the clutch pedal does not exceed the half-clutch judgment value higher than the fuel cut judgment value even after a lapse of time, the fuel cut is terminated and the fuel supply to the cylinder is restarted, and the predetermined time elapses. Until then, a vehicle control device was configured to prohibit the execution of fuel cuts again.

According to the present invention, in an MT vehicle, the problem of jerky behavior due to low-speed driving in a half-clutch state can be appropriately avoided.

The figure which shows the schematic structure of the internal combustion engine for a vehicle and the control device in one Embodiment of this invention. The figure which shows the schematic structure of the drive system of the vehicle in the same embodiment. The flow chart which shows the procedure example of the process which the control device of the same embodiment executes according to a program. The timing diagram explaining the content of the fuel cut control by the control device of the same embodiment. A timing diagram showing a pattern of conventional fuel cut control.

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows an outline of the vehicle internal combustion engine 100 according to the present embodiment. The internal combustion engine 100 in the present embodiment is a spark-ignition 4-stroke engine, and includes a plurality of cylinders 1 (for example, three cylinders, one of which is illustrated in FIG. 1). An injector 11 for injecting fuel is provided for each cylinder 1 in the vicinity of the intake port of each cylinder 1. Further, a spark plug 12 is attached to the ceiling of the combustion chamber of each cylinder 1. The spark plug 12 receives the application of the induced voltage generated by the ignition coil and induces a spark discharge between the center electrode and the ground electrode. The ignition coil is integrally built in the coil case together with the igniter which is a semiconductor switching element.

The intake passage 3 for supplying intake air takes in air from the outside and guides it to the intake port of each cylinder 1. An air cleaner 31, an electronic throttle valve 32, a surge tank 33, and an intake manifold 34 are arranged in this order from the upstream on the intake passage 3.

The exhaust passage 4 for discharging the exhaust guides the exhaust generated as a result of burning the fuel in the cylinder 1 to the outside from the exhaust port of each cylinder 1. An exhaust manifold 42 and a three-way catalyst 41 for purifying exhaust gas are arranged on the exhaust passage 4.

The exhaust gas recirculation device 2 opens and closes the external EGR passage 21 that connects the exhaust passage 4 and the intake passage 3, the EGR cooler 22 provided on the EGR passage 21, and the EGR passage 21 to open and close the EGR passage 21. The element is an EGR valve 23 that controls the flow rate of EGR gas flowing through the passage 21. The inlet of the EGR passage 21 is connected to a predetermined position downstream of the catalyst 41 in the exhaust passage 4. The outlet of the EGR passage 21 is connected to a predetermined position downstream of the throttle valve 32 in the intake passage 3, specifically, the surge tank 33.

In the present embodiment, an MT vehicle equipped with a manual transmission 300 is assumed as the vehicle. As is well known, in an MT vehicle, as shown in FIG. 2, the driver has a gear ratio between the crankshaft, which is the output shaft of the internal combustion engine 100, which is the drive source of the vehicle, and the drive wheels of the vehicle. A manual transmission 300 capable of manually changing the (reduction ratio) is interposed. The driver can arbitrarily change the shift position of the manual transmission 300 by operating the shift lever 301. Further, by positioning the shift lever 301 in the neutral position, the meshing of the gears in the manual transmission 300 is released, and the input shaft and the output shaft of the manual transmission 300 are separated from each other. As a result, the connection between the crankshaft of the internal combustion engine 100 and the drive wheels of the vehicle is disconnected, and torque is not transmitted between the crankshaft and the drive wheels.

A clutch 200 that can be switched between disconnection and disconnection by the driver's operation is arranged between the crankshaft of the internal combustion engine 100 and the input shaft of the manual transmission 300. When the driver steps on the clutch pedal 201, the clutch 200 is disengaged, and torque is not transmitted between the crankshaft of the internal combustion engine 100 and the transmission 300. When the driver stops stepping on the clutch pedal 201, the clutch 200 is reconnected and torque is transmitted between the crankshaft and the transmission 300.

The ECU (Electronic Control Unit) 0, which is a vehicle control device of the present embodiment, is a microcomputer system having a processor, a memory, an input interface, an output interface, and the like. The ECU 0 may be a plurality of ECUs or controllers connected to each other so as to be able to communicate with each other via a telecommunication line such as CAN (Control Area Network).

The input interface of ECU 0 is a vehicle speed signal a output from a vehicle speed sensor that detects the actual vehicle speed of the vehicle, a crank angle signal output from a crank angle sensor that detects the rotation angle of the crank shaft of the internal combustion engine 100 and the engine rotation speed. b. Accelerator opening signal c output from a sensor that detects the amount of depression of the accelerator pedal or the opening of the throttle valve 32 as the accelerator opening (so to speak, the engine load factor or engine torque required for the internal combustion engine 100). , Intake temperature / intake pressure signal d output from the temperature / pressure sensor that detects the intake temperature and intake pressure in the intake passage 3 (particularly, surge tank 33), and output from the water temperature sensor that detects the cooling water temperature of the internal combustion engine 100. Cooling water temperature signal e, shift position signal f output from the switch that detects the position of the shift lever 301, clutch stroke signal g output from the sensor that detects the amount of depression of the clutch pedal 201, and large pressure that detects atmospheric pressure. The atmospheric pressure signal h or the like output from the pressure pressure sensor is input.

From the output interface of ECU 0, the ignition signal i for the igniter of the spark plug 12, the fuel injection signal j for the injector 11, the opening operation signal k for the throttle valve 32, and the opening operation for the EGR valve 23. Outputs signal l and the like.

The processor of the ECU 0 interprets and executes a program stored in the memory in advance, calculates an operation parameter, and controls the operation of the internal combustion engine 100. The ECU 0 acquires various information a, b, c, d, e, f, g, h necessary for the operation control of the internal combustion engine 100 via the input interface, obtains the engine speed and the accelerator opening, and cylinders. Estimate the amount of air sucked into 1. Then, based on the engine speed, accelerator opening, intake amount, etc., the required fuel injection amount, fuel injection timing, fuel injection pressure, ignition timing, required EGR rate (or EGR gas amount), etc. corresponding to the intake amount, etc. Determine various operating parameters. The ECU 0 applies various control signals i, j, k, l corresponding to the operation parameters via the output interface.

When the driver manually shifts up the shift stage of the transmission 300, the amount of intake air and the amount of fuel injected into the cylinder 1 of the internal combustion engine 100 decrease, and the engine rotation slows down. In this transitional period, the combustion of the air-fuel mixture in the combustion chamber of the cylinder 1 becomes unstable, and the harmful substance HC is easily discharged.

Therefore, as shown in FIG. 3, in the ECU 0 of the present embodiment, the amount of depression of the accelerator pedal by the driver is 0 or less than a threshold value close to 0 (idle switch is ON) (step S1), and the clutch pedal by the driver. On condition that the amount of depression of 201 is equal to _{or greater than the fuel cut determination value T 1} (step S2), the fuel supply to the cylinder 1, that is, the fuel cut that temporarily suspends the fuel injection from the injector 11 is executed (step). S3). As a result, it is possible to suppress an increase in the amount of harmful substance HC emitted during the transitional period.

After the start of fuel cut, the accelerator pedal is depressed and the amount of depression is greater than 0 or a threshold close to 0 (idle switch is OFF) (step S5), or the engine speed drops below the return speed. If so (step S6), the fuel cut is completed and the fuel injection from the injector 11 is restarted (step S7).

In addition, the ECU 0 of the present embodiment counts the time elapsed from the start of the fuel cut (step S4). _{On that basis, if the depression amount of the clutch pedal 201 still does not exceed the half-clutch determination value T 2} (step S9) even though the predetermined time has elapsed from the start of the fuel cut (step S8), the fuel described above is used. Even if the cut end condition (step S5 or S6) is not satisfied, the fuel cut is ended and the fuel injection is restarted (step S10). The half-clutch determination value T ₂ referred to in step S9 is a value higher than the fuel cut determination value T _{1 referred to in step S2.} When the depression amount of the clutch pedal 201 _{becomes larger than the half-clutch determination value T 2} , it means that the driver fully depresses the clutch pedal 201 to disengage the clutch 200, that is, the half-clutch state is released.

Further, the time elapsed from the end of the fuel cut in step S10 is counted (step S12), and the fuel cut is prohibited again until the predetermined time elapses from the end of the fuel cut (step S13) (step S11). ), That is, even if the above-mentioned fuel cut execution conditions (steps S1 and S2) are satisfied, the fuel cut is not executed. After the predetermined time has elapsed, the prohibition on fuel cut is lifted (step S14).

By the processing of steps S4, S8 to S14, as shown in FIG. 4, the driver repeatedly depresses the accelerator pedal and takes his / her foot off the accelerator pedal in the half-clutch state, and the fuel cut execution condition (step S1). and S2) and the fuel cut end condition (step S5 or S6) even and is established in a short time alternately, after time t ₁ from the start time t ₀ of the fuel cut predetermined time has elapsed, forcibly from the fuel cut It is possible to return to the target and restart fuel injection. Furthermore, the fuel cut is not executed again during the period _{from the time point t 1} to the time point t _{2 when the predetermined time elapses.} Therefore, as compared with the conventional control shown in FIG. 5, fluctuations in engine torque and rotation speed are reduced, and the behavior of the vehicle is not jerky.

In the present embodiment, the control device 0 controls the traveling vehicle by transmitting the engine torque output by the internal combustion engine 100 to the drive wheels via the clutch 200 and the manual transmission 300, and the amount of depression of the accelerator pedal by the driver. Starts fuel cut to suspend fuel supply to cylinder 1 on condition that is 0 or less than the threshold value close to 0 and the amount of depression of the clutch pedal 201 by the driver is equal to _{or more than the fuel cut determination value T 1.} , The fuel cut is finished and the fuel supply to the cylinder 1 is restarted on the condition that the depression amount of the accelerator pedal becomes 0 or larger than the threshold value close to 0, or the engine rotation speed becomes equal to or less than the return rotation speed. If the depression amount of the clutch pedal 201 does not reach the half-clutch determination value T _{2 or more, which is higher than the fuel cut determination value T 1} , even after a predetermined time has elapsed from the start of the fuel cut, the fuel cut is terminated. The vehicle control device 0 is configured to restart the fuel supply to the cylinder 1 and prohibit the execution of the fuel cut again until a predetermined time elapses.

According to the present embodiment, in the MT vehicle, it is possible to appropriately avoid the problem that the behavior is jerky due to the low speed operation in the half-clutch state. As a result, the drivability of the MT vehicle can be kept high.

The present invention is not limited to the embodiments described in detail above. The specific configuration of each part and the specific processing procedure can be variously modified without departing from the spirit of the present invention.

The present invention can be applied to the control of an MT vehicle equipped with a manual transmission.

0 ... Control device (ECU)
1 ... Cylinder 11 ... Injector 100 ... Internal combustion engine 200 ... Clutch 201 ... Clutch pedal 300 ... Manual transmission 301 ... Shift lever b ... Crank angle signal c ... Accelerator opening signal g ... Clutch stroke signal j ... Fuel injection signal

Claims (1)

A control device that controls a traveling vehicle by transmitting engine torque output from an internal combustion engine to drive wheels via a clutch and a manual transmission.
Fuel that suspends fuel supply to the cylinder, provided that the amount of depression of the accelerator pedal by the driver is 0 or less than the threshold value close to 0, and the amount of depression of the clutch pedal by the driver is greater than or equal to the fuel cut judgment value. Start cutting,
The fuel cut is completed and the fuel supply to the cylinder is restarted on the condition that the amount of depression of the accelerator pedal becomes 0 or greater than the threshold value close to 0, or the engine speed becomes less than or equal to the return speed. can be,
If the amount of depression of the clutch pedal does not exceed the half-clutch judgment value, which is higher than the fuel cut judgment value, even after a predetermined time has passed from the start of the fuel cut, the fuel cut is terminated and the fuel supply to the cylinder is restarted. , A vehicle control device that prohibits the execution of fuel cut again until a predetermined time elapses.

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