Control device

Abstract

To generate negative pressure in a brake device while suppressing deterioration of a catalyst.SOLUTION: A control device for a vehicle includes an intake passage, an exhaust passage, a catalyst, an internal combustion engine, a motor, a brake device and one or more wheels. The motor generates power to be transmitted to the one or more wheels. The intake passage is a passage in which air flowing into the internal combustion engine flows. The exhaust passage is a passage in which exhaust gas flowing out from the internal combustion engine flows. The catalyst is provided in the exhaust passage. The brake device uses negative pressure in the intake passage to reduce rotating speed of the one or more wheels. The control device causes the internal combustion engine to start a combustion operation in the case where the internal combustion engine is stopped, a temperature of the catalyst is higher than a predetermined temperature and pressure of the brake device is higher than predetermined pressure.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a control device for an internal combustion engine. [Background technology]

[0002] A known example of a conventional invention relating to a control device for an internal combustion engine is a control device for a hybrid vehicle described in Patent Document 1. In this engine control device, when the negative pressure stored in the brake booster falls below a lower limit threshold, motoring is performed to rotate the internal combustion engine using a motoring electric motor. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-54241 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the catalyst is hot and the air-fuel ratio is lean, a large amount of hot oxygen comes into contact with the catalyst. In this case, the catalyst is likely to deteriorate. During motoring, the air-fuel mixture is not burned, so the oxygen concentration in the exhaust increases. In other words, the air-fuel ratio becomes lean. Therefore, in the control device described in Patent Document 1, if the motoring motor performs motoring when the catalyst temperature is high, the catalyst is likely to deteriorate.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a control device that can generate negative pressure in a brake device while suppressing deterioration of the catalyst. [Means for solving the problem]

[0006] A first aspect of the present invention is A control device for a vehicle including an intake path, an exhaust path, a catalyst, an internal combustion engine, a motor, a brake device, and one or more wheels, the motor generates power that is transmitted to the one or more wheels; the intake path is a path through which air flows into the internal combustion engine, the exhaust path is a path through which exhaust gas flowing out from the internal combustion engine flows, the catalyst is provided in the exhaust path, The brake device reduces the rotational speed of the one or more wheels by utilizing negative pressure in the intake path, the control device causes the internal combustion engine to start combustion operation when the internal combustion engine is stopped, the temperature of the catalyst is higher than a predetermined temperature, and the pressure of the brake device is higher than a predetermined pressure; It is a control device.

[0007] A second aspect of the present invention is the control device causes the internal combustion engine to start a motoring operation when the internal combustion engine is stopped, the temperature of the catalyst is lower than the predetermined temperature, and the pressure of the brake device is higher than the predetermined pressure; 1 is a control device according to a first aspect.

[0008] A third aspect of the present invention is the control device, when the internal combustion engine is stopped, the temperature of the catalyst is higher than the predetermined temperature, and the pressure of the brake device is higher than the predetermined pressure, causes the internal combustion engine to start a combustion operation, thereby suppressing deterioration of the catalyst caused by the catalyst being at a high temperature and the air-fuel ratio being in a lean state; The control device according to the first or second aspect.

[0009] A fourth aspect of the present invention is The vehicle further includes a generator; the generator is operated by the internal combustion engine to generate electric power; the motor generates power transmitted to the one or more wheels of the vehicle using the electric power generated by the generator; the internal combustion engine does not generate power that is transmitted to the one or more wheels; The control device is according to any one of the first to third aspects. [Effects of the Invention]

[0010] According to the present invention, it is possible to generate negative pressure in the brake device while suppressing deterioration of the catalyst. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram of a vehicle 10 . [Figure 2] FIG. 2 is a schematic diagram of a vehicle 10 including an internal combustion engine 26 . [Figure 3] FIG. 3 is a flowchart showing the process executed by the control device 100. DETAILED DESCRIPTION OF THE INVENTION

[0012] (Embodiment) [Vehicle structure] The structure of a vehicle 10 equipped with a control device 100 according to one embodiment of the present invention will be described below with reference to the drawings. Fig. 1 is a schematic diagram of the vehicle 10. Fig. 2 is a schematic diagram of the vehicle 10 including an internal combustion engine 26.

[0013] The vehicle 10 is, for example, a four-wheeled automobile. The vehicle 10 is a hybrid vehicle. In this embodiment, the vehicle 10 is a series hybrid vehicle. As shown in Fig. 1, the vehicle 10 includes an internal combustion engine 26, a battery 36, a generator 50, a motor 52, an inverter 54, a power transmission device 56, a left front wheel 58L, and a right front wheel 58R (one or more wheels).

[0014] The internal combustion engine 26 generates power using gasoline as fuel. The internal combustion engine 26 generates power to operate the generator 50, which will be described later. The internal combustion engine 26 does not generate power that is transmitted to the left front wheel 58L and the right front wheel 58R (one or more wheels). The internal combustion engine 26 is a four-stroke engine. The internal combustion engine 26 is an engine that has one or more cylinders, but generally an engine that has multiple cylinders. When the internal combustion engine 26 is an engine that has multiple cylinders, the multiple cylinders may be arranged in a single row, two rows, or four rows.

[0015] The generator 50 is connected to the internal combustion engine 26. The generator 50 generates electric power by being operated by the internal combustion engine 26. The generator 50 is, for example, an AC generator.

[0016] The battery 36 stores the power generated by the generator 50. The battery 36 is a secondary battery that can be charged and discharged. The battery 36 is, for example, a lithium-ion battery or an all-solid-state battery.

[0017] The motor 52 generates power using the power generated by the generator 50, which is transmitted to a left front wheel 58L and a right front wheel 58R (one or more wheels) of the vehicle 10. In this embodiment, the motor 52 generates power to run the vehicle 10 using the power stored in the battery 36. The power stored in the battery 36 is power generated by the generator 50. However, the battery 36 may store power generated when the vehicle 10 decelerates, in addition to the power generated by the generator 50. The motor 52 is, for example, an AC motor.

[0018] The inverter 54 controls the motor 52. In this embodiment, the inverter 54 converts the AC current generated by the generator 50 into DC current and supplies the DC current to the battery 36. As a result, the battery 36 is charged with the power generated by the generator 50. The inverter 54 also converts the DC current generated by the battery 36 into AC current and supplies the AC current to the motor 52. The motor 52 operates on the AC current supplied from the inverter 54.

[0019] The power generated by the motor 52 is transmitted to the power transmission device 56. The power transmission device 56 transmits the power generated by the motor 52 to a left front wheel 58L and a right front wheel 58R. Such a power transmission device 56 is, for example, a reducer and a differential.

[0020] 2, the vehicle 10 further includes an injector 31, an electronic throttle 32, a catalyst 33, a temperature sensor 38, a pressure sensor 39, a throttle position sensor 42, a brake device 60, a control device 100, a storage device 102, an intake path R1, and an exhaust path R2 in addition to the internal combustion engine 26. The internal combustion engine 26 also includes a piston 27, a crankshaft 29, and a spark plug 30.

[0021] The intake path R1 is a path through which air flows into the internal combustion engine 26. An injector 31 is provided in the intake path R1. The injector 31 injects fuel. This causes an air-fuel mixture to be formed in the intake path R1. The intake path R1 is connected to an intake port of the internal combustion engine 26. Therefore, the air-fuel mixture flows from the intake path R1 through the intake port into the combustion chamber of the internal combustion engine 26.

[0022] In the internal combustion engine 26, the combustion of the air-fuel mixture causes the piston 27 to move up and down. The up and down movement of the piston 27 is converted into the rotation of the crankshaft 29. As a result, the internal combustion engine 26 generates power. At this time, the internal combustion engine 26 generates exhaust gas.

[0023] The exhaust path R2 is connected to an exhaust port of the internal combustion engine 26. The exhaust path R2 is a path through which exhaust gas flowing out from the internal combustion engine 26 flows.

[0024] The catalyst 33 is provided in the exhaust path R2. The catalyst 33 removes hydrocarbons, carbon monoxide, and nitrogen oxides from the exhaust gas. The catalyst 33 is, for example, a three-way catalyst.

[0025] The temperature sensor 38 generates a temperature signal g that indicates the temperature of the catalyst 33. The temperature signal g is output to the control device 100.

[0026] The electronic throttle 32 is a valve that adjusts the amount of air passing through the intake path R1 (hereinafter referred to as the intake air amount). The electronic throttle 32 is provided in the intake path R1. The electronic throttle 32 opens and closes the intake path R1 under the control of a control device 100, which will be described later.

[0027] The braking device 60 utilizes the negative pressure in the intake path R1 to reduce the rotational speed of the left front wheel 58L and the right front wheel 58R (one or more wheels). The braking device 60 includes a brake booster, brake pedal, brake caliper, brake pads, and brake discs (not shown). The brake booster is connected to the intake path R1. Because negative pressure is generated in the intake path R1, the pressure in the brake booster is maintained at a negative pressure. The brake booster uses the negative pressure to increase the brake pedal force applied by the driver and transmits it to the master cylinder. In other words, the brake booster assists the driver in operating the brake pedal. The brake force transmitted to the master cylinder is converted into hydraulic pressure and transmitted to the brake calipers provided on each wheel. The brake calipers apply force to the brake discs using the brake pads, thereby reducing the rotational speed of the brake discs and wheels.

[0028] The pressure sensor 39 generates a pressure signal h indicative of the pressure of the brake booster of the braking device 60. The pressure signal h is output to the control device 100.

[0029] The control device 100 is an ECU (Engine Control Unit). The control device 100 controls an internal combustion engine 26, an ignition plug 30, an injector 31, and an electronic throttle 32. The storage device 102 is a combination of a ROM (Read Only Memory) and a RAM (Random Access Memory). The storage device 102 stores programs executed by the control device 100.

[0030] The control device 100 receives a vehicle speed signal a, a crank angle signal b, an accelerator opening signal c, an intake air temperature / intake pressure signal d, a cooling water temperature signal e, an atmospheric pressure signal f, a temperature signal g, and a pressure signal h.

[0031] The vehicle speed signal a is output from a vehicle speed sensor that detects the actual vehicle speed of the vehicle 10. The crank angle signal b is output from a crank angle sensor that detects the angle of the crankshaft 29 of the internal combustion engine 26. The control device 100 can calculate the rotational speed of the internal combustion engine 26 based on the crank angle signal b. The accelerator opening signal c is output from a sensor that detects the depression amount of the accelerator pedal or the opening degree of the electronic throttle 32 as the accelerator opening (in other words, the required engine load factor). The intake air temperature / intake pressure signal d is output from a temperature / pressure sensor that detects the intake air temperature and intake pressure in the intake path R1. The coolant temperature signal e is output from a water temperature sensor that detects the coolant temperature, which indicates the temperature of the internal combustion engine 26. The atmospheric pressure signal f is output from an atmospheric pressure sensor that detects the atmospheric pressure.

[0032] The control device 100 calculates the rotation speed of the internal combustion engine 26 and estimates the amount of intake air filling the cylinders of the internal combustion engine 26 based on the vehicle speed signal a, crank angle signal b, accelerator opening signal c, intake air temperature / intake pressure signal d, coolant temperature signal e, and atmospheric pressure signal f. Then, the control device 100 determines the fuel injection amount, fuel injection timing, fuel injection pressure, and ignition timing based on the rotation speed and intake air amount of the internal combustion engine 26. The control device 100 generates an ignition signal i, a fuel injection signal j, and an opening control signal k based on the fuel injection amount, fuel injection timing, fuel injection pressure, and ignition timing.

[0033] The ignition signal i is output to an igniter. The igniter generates a spark in the spark plug 30 based on the ignition signal i. The fuel injection signal j is output to the injector 31. The injector 31 injects fuel based on the fuel injection signal j. The opening control signal k is output to the electronic throttle 32. The electronic throttle 32 opens and closes the throttle valve based on the opening control signal k.

[0034] [Operation of the control device 100] Next, the processing executed by the control device 100 will be described with reference to the drawings. Fig. 3 is a diagram showing a flowchart executed by the control device 100. The control device 100 executes the flowchart of Fig. 3 by reading out a program stored in the storage device 102.

[0035] First, the control device 100 determines whether the internal combustion engine 26 is stopped (step S1). The internal combustion engine 26 being stopped means that the crankshaft 29 is not rotating. Therefore, in step S1, the control device 100 determines whether the internal combustion engine 26 is stopped based on the crank angle signal b. However, in step S1, the vehicle 10 is running using the power generated by the motor 52. If the internal combustion engine 26 is stopped, the process proceeds to step S2. If the internal combustion engine 26 is not stopped, the process returns to step S1.

[0036] When the internal combustion engine 26 is stopped, the control device 100 determines whether the pressure of the brake booster of the braking device 60 is higher than a predetermined pressure based on the pressure signal h (step S2). In step S2, the control device 100 determines whether the negative pressure of the brake booster is insufficient. The predetermined pressure is determined by experimentation. The predetermined pressure is, for example, 60 kPa. If the pressure of the brake booster is higher than the predetermined pressure, the control device 100 determines that the negative pressure of the brake booster is insufficient. Then, the process proceeds to step S3. If the pressure of the brake booster is not higher than the predetermined pressure, the control device 100 determines that the negative pressure of the brake booster is not insufficient. Then, the process returns to step S1.

[0037] If the pressure of the brake booster is higher than the predetermined pressure, the control device 100 determines whether the temperature of the catalyst 33 is higher than a predetermined temperature based on the temperature signal g (step S3). The predetermined temperature is determined by experimentation. The predetermined temperature is, for example, 800°C. If the temperature of the catalyst 33 is higher than the predetermined temperature, the process proceeds to step S4. If the temperature of the catalyst 33 is not higher than the predetermined temperature, the process proceeds to step S5.

[0038] If the temperature of the catalyst 33 is higher than the predetermined temperature, the control device 100 starts the combustion operation of the internal combustion engine 26 (step S4). In this way, when the internal combustion engine 26 is stopped, the temperature of the catalyst 33 is higher than the predetermined temperature, and the pressure of the brake booster of the braking device 60 is higher than the predetermined pressure, the control device 100 starts the combustion operation of the internal combustion engine 26, thereby suppressing deterioration of the catalyst 33 caused by the catalyst 33 being high in temperature and the air-fuel ratio being in a lean state. The combustion operation is an operation in which the injector 31 injects fuel and the spark plug 30 generates a spark, thereby combusting the air-fuel mixture in the internal combustion engine 26. After this, the process proceeds to step S6.

[0039] If the temperature of the catalyst 33 is not higher than the predetermined temperature, the control device 100 starts the motoring operation of the internal combustion engine 26 (step S5). In this way, the control device 100 starts the motoring operation of the internal combustion engine 26 when the internal combustion engine 26 is stopped, the temperature of the catalyst 33 is equal to or lower than the predetermined temperature, and the pressure of the brake booster of the braking device 60 is higher than the predetermined pressure. Motoring operation is an operation in which the generator 50 functions as a motor to rotate the crankshaft 29 of the internal combustion engine 26. In motoring operation, the injector 31 does not inject fuel and the spark plug 30 does not generate a spark. Therefore, the air-fuel mixture does not burn in the internal combustion engine 26. After this, the process proceeds to step S6.

[0040] In step S6, the control device 100 determines whether or not to end this process (step S6). In step S6, the control device 100 determines whether or not to end the running of the vehicle 10. That is, the control device 100 determines whether or not the driver has pressed the start / stop button for the internal combustion engine 26. If the running of the vehicle is to be stopped, the control device 100 determines to end this process. If the running of the vehicle is not to be stopped, this process returns to step S1.

[0041] [effect] The control device 100 can generate negative pressure in the braking device 60 while suppressing deterioration of the catalyst 33. More specifically, when the catalyst 33 is at a high temperature and the air-fuel ratio is lean, a large amount of high-temperature oxygen comes into contact with the catalyst 33. As a result, deterioration of the catalyst 33 is likely to progress. Therefore, the control device 100 causes the internal combustion engine 26 to start combustion operation when the internal combustion engine 26 is stopped, the temperature of the catalyst 33 is higher than a predetermined temperature, and the pressure of the brake booster of the braking device 60 is higher than a predetermined pressure. When the internal combustion engine 26 performs combustion operation, the air-fuel ratio approaches a stoichiometric state and is no longer lean. As a result, deterioration of the catalyst 33 is suppressed. Furthermore, when the internal combustion engine 26 performs combustion operation, negative pressure is generated in the intake path R1. This reduces the pressure in the brake booster. As a result, negative pressure can be generated in the braking device 60.

[0042] The control device 100 can generate negative pressure in the braking device 60 while improving the fuel efficiency of the internal combustion engine 26. More specifically, unless the catalyst 33 is at a high temperature, deterioration of the catalyst 33 is unlikely to progress even if the air-fuel ratio is lean. Therefore, the control device 100 causes the internal combustion engine 26 to start motoring operation when the internal combustion engine 26 is stopped, the temperature of the catalyst 33 is below a predetermined temperature, and the pressure of the brake booster of the braking device 60 is higher than a predetermined pressure. When the internal combustion engine 26 performs motoring operation, negative pressure is generated in the intake path R1. This reduces the pressure in the brake booster. As a result, negative pressure can be generated in the braking device 60. Furthermore, during motoring operation, the injector 31 does not inject fuel. This improves the fuel efficiency of the internal combustion engine 26.

[0043] (Other embodiments) The control device according to the present invention is not limited to the control device 100, and can be modified within the scope of the gist thereof.

[0044] The fuel may be a hydrocarbon fuel other than gasoline, or an alcohol fuel such as bioethanol fuel.

[0045] The automobile may be a three-wheeled automobile or a two-wheeled automobile. The two-wheeled automobile is a leaning vehicle in which the body leans in the same direction as the direction of travel around the corner. The three-wheeled automobile may be a leaning vehicle or a vehicle that rolls in the opposite direction to the direction of travel around the corner.

[0046] The control device 100 may determine whether the pressure in the intake path R1 is higher than a predetermined value, instead of determining whether the pressure in the brake booster is higher than a predetermined pressure. In this case, the pressure sensor 39 is provided in the intake path R1. In this way, the control device 100 may indirectly determine whether the pressure in the brake booster is higher than a predetermined pressure by determining whether the pressure in the intake path R1 is higher than a predetermined pressure. The predetermined pressure of the brake booster may be different from the predetermined pressure of the intake path R1.

[0047] The predetermined pressure does not have to be a constant value. For example, the predetermined pressure may vary depending on the vehicle speed. In this case, the higher the vehicle speed, the lower the predetermined pressure.

[0048] The predetermined temperature does not have to be a constant value.

[0049] The predetermined pressure and the predetermined temperature may be any values ​​suitable for suppressing deterioration of the catalyst 33 caused by the catalyst 33 being at a high temperature and the air-fuel ratio being in a lean state. These values ​​are determined by experiment.

[0050] Although the vehicle 10 is a series hybrid vehicle, it may also be a parallel hybrid vehicle.

[0051] The pressure signal h may be a signal indicating the negative pressure of the brake booster. In this case, in step S2, the control device 100 determines, based on the pressure signal h, whether the negative pressure of the brake booster of the braking device 60 is higher than a predetermined pressure. The predetermined pressure is 40 kPa.

[0052] The control device 100 may cause the internal combustion engine 26 to start combustion operation when the internal combustion engine 26 is stopped, the temperature of the catalyst 33 is equal to or higher than a predetermined temperature, and the pressure of the brake booster of the braking device 60 is higher than a predetermined pressure. In this case, the control device 100 causes the internal combustion engine 26 to start motoring operation when the internal combustion engine 26 is stopped, the temperature of the catalyst 33 is lower than the predetermined temperature, and the pressure of the brake booster of the braking device 60 is higher than the predetermined pressure.

[0053] The control device 100 may cause the internal combustion engine 26 to start combustion operation when the internal combustion engine 26 is stopped, the temperature of the catalyst 33 is higher than a predetermined temperature, and the pressure of the brake booster of the braking device 60 is equal to or higher than a predetermined pressure. In this case, the control device 100 causes the internal combustion engine 26 to start motoring operation when the internal combustion engine 26 is stopped, the temperature of the catalyst 33 is equal to or lower than the predetermined temperature, and the pressure of the brake booster of the braking device 60 is equal to or higher than the predetermined pressure.

[0054] The control device 100 may cause the internal combustion engine 26 to start combustion operation when the internal combustion engine 26 is stopped, the temperature of the catalyst 33 is equal to or higher than a predetermined temperature, and the pressure of the brake booster of the braking device 60 is equal to or higher than a predetermined pressure. In this case, the control device 100 causes the internal combustion engine 26 to start motoring operation when the internal combustion engine 26 is stopped, the temperature of the catalyst 33 is lower than the predetermined temperature, and the pressure of the brake booster of the braking device 60 is equal to or higher than the predetermined pressure. [Explanation of symbols]

[0055] 10: Vehicle 26: Internal combustion engine 27: Piston 29: Crankshaft 30: Spark plug 31: Injector 32: Electronic throttle 33: Catalyst 36: Battery 38: Temperature sensor 39: Pressure sensor 42: Throttle position sensor 50: Generator 52: Motor 54: Inverter 56: Power transmission device 58L: Left front wheel 58R: Right front wheel 60: Brake device 100: Control device 102: Storage device R1: Intake path R2: Exhaust route

Claims

1. A control device for a vehicle including an intake path, an exhaust path, a catalyst, an internal combustion engine, a motor, a brake device, and one or more wheels, the motor generates power that is transmitted to the one or more wheels; the intake path is a path through which air flows into the internal combustion engine, the exhaust path is a path through which exhaust gas flowing out from the internal combustion engine flows, the catalyst is provided in the exhaust path, The brake device reduces the rotational speed of the one or more wheels by utilizing negative pressure in the intake path, the control device causes the internal combustion engine to start combustion operation when the internal combustion engine is stopped, the temperature of the catalyst is higher than a predetermined temperature, and the pressure of the brake device is higher than a predetermined pressure; Control device.

2. the control device causes the internal combustion engine to start a motoring operation when the internal combustion engine is stopped, the temperature of the catalyst is lower than the predetermined temperature, and the pressure of the brake device is higher than the predetermined pressure; The control device according to claim 1 .

3. the control device, when the internal combustion engine is stopped, the temperature of the catalyst is higher than the predetermined temperature, and the pressure of the brake device is higher than the predetermined pressure, causes the internal combustion engine to start a combustion operation, thereby suppressing deterioration of the catalyst caused by the catalyst being at a high temperature and the air-fuel ratio being in a lean state; The control device according to claim 1 or 2.

4. The vehicle further includes a generator; the generator is operated by the internal combustion engine to generate electric power; the motor generates power transmitted to the one or more wheels of the vehicle using the electric power generated by the generator; the internal combustion engine does not generate power that is transmitted to the one or more wheels; The control device according to claim 1 or 2.

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