JP2024003883A - Vehicle control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle control device that can avoid behavior of a vehicle from becoming unstable.

SOLUTION: The vehicle control device, which is equipped with an internal combustion engine that applies driving force to a driving wheel and a braking device that applies braking force to the driving wheel, is provided with: a fuel cut control part that executes fuel-cut control of stopping fuel supply to some cylinders of a plurality of cylinders of the internal combustion engine; a vehicle stability control part that executes vehicle stabilization control of stabilizing behavior of the vehicle by controlling the driving force and braking force; and a prohibiting part that prohibits the fuel-cut control from being executed during execution of the vehicle stabilization control.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a vehicle control device.

BACKGROUND ART Fuel cut control for stopping fuel supply to some cylinders among a plurality of cylinders of an internal combustion engine is known (for example, see Patent Document 1). Furthermore, vehicle stability control is known in which the driving force and braking force applied to the drive wheels are controlled to stabilize the behavior of the vehicle (for example, see Patent Document 2).

JP 2021-060027 Publication Japanese Patent Application Publication No. 10-231925

In the above-mentioned fuel cut control, since fuel supply is stopped only to some cylinders, fluctuations in the output torque of the internal combustion engine increase. Here, if such fuel cut control is executed while the above vehicle stability control is being executed, the behavior of the vehicle may become unstable.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a vehicle control device that can prevent the behavior of the vehicle from becoming unstable.

The above object is a control device for a vehicle having an internal combustion engine that applies driving force to driving wheels, and a braking device that applies braking force to the driving wheels, wherein one of a plurality of cylinders of the internal combustion engine a fuel cut control section that executes fuel cut control that stops fuel supply to the cylinders of the vehicle; and a vehicle stability control section that executes vehicle stability control that controls the driving force and braking force to stabilize the behavior of the vehicle. This can be achieved by a vehicle control device including a control section and a prohibition section that prohibits execution of the fuel cut control while the vehicle stability control is being executed.

According to the present invention, it is possible to provide a vehicle control device that can prevent the behavior of the vehicle from becoming unstable.

FIG. 1 is a schematic configuration diagram of a vehicle. FIGS. 2A and 2B are examples of graphs showing the torques generated in cylinders #1 to #4. FIG. 3 is a flowchart showing an example of one-cylinder fuel cut prohibition control executed by the ECU.

[Schematic configuration of vehicle]
FIG. 1 is a schematic configuration diagram of a vehicle 1. As shown in FIG. The vehicle 1 is an engine vehicle equipped with an engine 10 as a drive source, but is not limited thereto, and may be a hybrid vehicle equipped with an engine and a motor as a drive source. Engine 10 is an example of an internal combustion engine, and is a four-cylinder in-line gasoline engine having four cylinders #1 to #4, with cylinder #1 being shown in FIG. Note that the number of cylinders in the engine 10 is not limited to this, and it may also be a diesel engine. Each of the four cylinders #1 to #4 of the engine 10 is provided with a piston 13. The piston 13 is connected to a crankshaft 15, which is the output shaft of the engine 10, via a connecting rod 14. The reciprocating motion of the piston 13 is converted into rotational motion of the crankshaft 15 by the connecting rod 14. The driving force of the crankshaft 15 is transmitted from the engine 10 to the left and right drive wheels 50 via a torque converter, an automatic transmission, and a differential gear.

A combustion chamber 16 is formed above the piston 13 in each of the cylinders #1 to #4, and a spark plug 18 that ignites a mixture of fuel and air is attached to this combustion chamber 16. It is being The timing of ignition of the air-fuel mixture by the spark plug 18 is adjusted by an igniter 19 provided above the spark plug 18.

In each intake port 20a forming a part of the intake passage 20, a port injection valve 22 for injecting fuel into the intake port 20a is provided for each of the cylinders #1 to #4. The engine 10 is provided with in-cylinder injection valves 17 that inject fuel into each combustion chamber 16, respectively. Although the engine 10 is provided with both an in-cylinder injection valve 17 and a port injection valve 22, the present invention is not limited to this, and an engine may be provided with either one of them.

The combustion chamber 16 is communicated with an intake passage 20 and an exhaust passage 21 . The intake passage 20 is provided with a throttle valve 23 that regulates the amount of air introduced into the combustion chamber 16.

An air-fuel ratio sensor 35, a three-way catalyst 41, and a GPF (Gasoline Particulate Filter) 42 are provided in the exhaust passage 21 in this order from the upstream side. The three-way catalyst 41 contains, for example, a catalytic metal such as platinum (Pt), palladium (Pd), or rhodium (Rh), has an oxygen storage ability, and purifies NOx, HC, and CO. The GPF 42 has a structure in which the front and rear ends of adjacent cells among a large number of cells are alternately sealed in a porous ceramic structure.

The wheel brake device 60 is an example of a brake device that applies braking force to the drive wheels 50. The wheel brake device 60 supplies brake hydraulic pressure (=braking hydraulic pressure) to a wheel cylinder provided in a wheel brake in response to a braking operation (for example, a brake pedal operation) by a driver. In this wheel brake device 60, under normal conditions, brake fluid pressure (=master cylinder oil pressure) generated from the brake master cylinder and corresponding to the depression force on the brake pedal is directly supplied to the wheel cylinders as braking oil pressure. .

ECU (Electronic Control Unit) 100 is an electronic control unit that performs control processing regarding engine 10. The ECU 100 is mainly composed of a computer including a CPU (Central Processing Unit), volatile and nonvolatile memories such as a RAM (Random Access Memory) and a ROM (Read Only Memory). ECU 100 implements various control processes regarding engine 10 by executing programs installed in memory on CPU. Various sensors are connected to the ECU 100, which will be described in detail later. The ECU 100 is an example of a vehicle control device, and functionally implements a fuel cut control section, a vehicle stability control section, and a prohibition section, which will be described in detail later.

An accelerator opening sensor 31, a water temperature sensor 32, an air flow meter 33, a crank angle sensor 34, and an air-fuel ratio sensor 35 are connected to the ECU 100, and output signals from these various sensors are input. The accelerator opening sensor 31 detects the accelerator opening. Water temperature sensor 32 detects the temperature of cooling water that cools engine 10 . Air flow meter 33 detects the amount of intake air. The crank angle sensor 34 detects the rotation angle of the crankshaft 15. The air-fuel ratio sensor 35 is provided in the exhaust passage 21 upstream of the three-way catalyst 41 and detects the air-fuel ratio of exhaust gas flowing into the three-way catalyst 41.

The ECU 100 calculates the engine speed based on the detected value of the crank angle sensor 34, and calculates the engine load based on the engine speed and the intake air amount. The ECU 100 calculates the target rotation speed and target load based on the accelerator opening degree, and controls the fuel injection amount, intake air amount, and ignition timing so that the engine rotation speed and load become the target rotation speed and target load, respectively. do.

The ECU 100 executes vehicle stability control that stabilizes the behavior of the vehicle 1 by controlling the driving force and braking force applied to the drive wheels 50 by controlling the engine 10 and the wheel brake device 60. Vehicle stability control includes, for example, ABS (Anti-lock Brake System) control, TRC (Traction Control) control, and VSC (Vehicle Stability Control) control. In these controls, the brake hydraulic pressure required for each control is supplied to the wheel cylinders in addition to the brake hydraulic pressure corresponding to the above-mentioned pedal force. In order to ensure the stability of the vehicle 1 when braking due to a sudden braking operation or when braking on a slippery road surface, ABS control applies braking force to each wheel and drive wheel 50 to prevent wheels from locking. Control the driving force to. In order to ensure the stability of the vehicle 1 when starting/accelerating on a slippery road surface or accelerating while turning, the TRC control suppresses slip of the drive wheels 50 and secures driving force according to the road surface conditions. Thus, the driving force and braking force to the drive wheels 50 are controlled. The VSC control controls the braking force to each wheel and the driving force to the driving wheels 50 so as to alleviate rear wheel skidding or front wheel skidding in order to ensure stability in the turning direction of the vehicle 1. Vehicle stability control is an example of control executed by the vehicle stability control section.

[1 cylinder fuel cut control]
The ECU 100 estimates the amount of soot accumulated in the GPF 42, and issues a regeneration request when the amount of accumulated soot exceeds a predetermined value. The amount of soot deposited in the GPF 42 may be estimated based on, for example, the driving history of the engine 10 since the completion of the previous regeneration control, or may be estimated based on the differential pressure before and after the GPF 42, It may be estimated by other known methods. When there is a regeneration request for the GPF 42 in this way, the ECU 100 performs fuel cut control (hereinafter referred to as single cylinder fuel cut control) to stop the fuel supply to any one of the four cylinders #1 to #4 of the engine 10. ). For example, fuel supply is stopped to cylinder #1, and the fuel injection amount and intake air amount are adjusted to other cylinders #2 to #4 so that the air-fuel ratio is richer than the stoichiometric air-fuel ratio. . As a result, surplus fuel discharged from the cylinders controlled to have a rich air-fuel ratio adheres to the GPF 42 and is burned in a lean atmosphere created by air discharged from the cylinders to which fuel supply has been stopped. As a result, the soot deposited on the GPF 42 is burned and the GPF 42 is regenerated.

FIGS. 2A and 2B are examples of graphs showing the torques generated in cylinders #1 to #4. FIG. 2A is a graph in a normal operating state when the one-cylinder fuel cut control is stopped. FIG. 2B is a graph when one cylinder fuel cut control is being executed. While the one-cylinder fuel cut control is being executed, the torque generated in cylinder #1 becomes zero. Therefore, so that the average value of the generated torque of cylinders #1 to #4 is the same in the normal operating state and during execution of single cylinder fuel cut control, the generated torque of each cylinder #2 to #4 is The fuel injection amount, intake air amount, and ignition timing are controlled to increase the amount of fuel injection. Thereby, the output torque of the engine 10 during execution of the one-cylinder fuel cut control can be controlled in the same manner as in the normal operating state. The above control is an example of control executed by the fuel cut control section.

However, while the one-cylinder fuel cut control is being executed, combustion does not occur in cylinder #1, so the output torque of the engine 10 decreases during the combustion stroke of cylinder #1, and the combustion stroke of the other cylinders #2 to #4 decreases. The output torque of the engine 10 increases. Therefore, compared to the normal operating state, fluctuations in the output torque of the engine 10 increase during execution of the one-cylinder fuel cut control.

As described above, if the one-cylinder fuel cut control described above is executed while the vehicle stability control is being executed, the output torque of the engine 10 fluctuates even though the vehicle stability control is being executed, and the vehicle behavior may become unstable. Therefore, the ECU 100 of this embodiment executes the following one-cylinder fuel cut prohibition control.

[1 cylinder fuel cut prohibition control]
Next, the one-cylinder fuel cut prohibition control executed by the ECU 100 will be described. FIG. 3 is a flowchart showing an example of one-cylinder fuel cut prohibition control executed by the ECU 100. This control is repeatedly executed with the ignition turned on.

ECU 100 determines whether vehicle stability control is being executed (step S1). Vehicle stability control includes ABS control, TRC control, and VSC control as described above, and when at least one of these controls is being executed, it is determined that vehicle stability control is being executed.

If Yes in step S1, the ECU 100 prohibits execution of the one-cylinder fuel cut control (step S2). Specifically, the ECU 100 turns on a prohibition flag for one-cylinder fuel cut control. Step S2 is an example of a process executed by the prohibition unit. In the case of No in step S1, the ECU 100 permits execution of the one-cylinder fuel cut control (step S3). Specifically, ECU 100 turns off the prohibition flag for one-cylinder fuel cut control. If there is a request to execute the one-cylinder fuel cut control and the above prohibition flag is OFF, the ECU 100 executes the one-cylinder fuel cut control, and if the prohibition flag is ON, the ECU 100 does not execute the one-cylinder fuel cut control. In this manner, by prohibiting the execution of the one-cylinder fuel cut control while the vehicle stability control is being executed, it is possible to prevent the behavior of the vehicle from becoming unstable.

In the above embodiment, one-cylinder fuel cut control for stopping fuel supply to one cylinder among the plurality of cylinders #1 to #4 has been described as an example, but the present invention is not limited to this. For example, fuel cut control may be used to supply fuel to at least one cylinder while stopping fuel supply to the remaining cylinders. For example, if it is a V-type engine and GPFs corresponding to the left and right banks are provided, fuel cut control is executed for one of the plurality of cylinders in the left bank and one of the plurality of cylinders in the right bank. You may. Furthermore, in the one-cylinder fuel cut described above, the average value of the torque generated in cylinders #1 to #4 is controlled to be the same as in the normal operating state, but the present invention is not limited to this.

In the above embodiment, the vehicle 1 is described as an example in which only the engine 10 is mounted as a driving power source, but the present invention is not limited thereto. For example, the vehicle may be a hybrid vehicle that includes a motor in addition to an engine as a driving power source.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to these specific embodiments, and various modifications and variations can be made within the scope of the gist of the present invention as described in the claims. Changes are possible.

1 Vehicle 10 Engine (internal combustion engine)
50 Drive wheel 60 Wheel brake device (braking device)
100 ECU (vehicle control device, fuel cut control section, vehicle stability control section, inhibition section)

Claims (1)

A control device for a vehicle, comprising an internal combustion engine that applies driving force to driving wheels, and a braking device that applies braking force to the driving wheels,
a fuel cut control unit that executes fuel cut control to stop fuel supply to some of the plurality of cylinders of the internal combustion engine;
a vehicle stability control unit that executes vehicle stability control that controls the driving force and the braking force to stabilize the behavior of the vehicle;
A control device for a vehicle, comprising: a prohibition unit that prohibits execution of the fuel cut control while the vehicle stability control is being executed.

Images