Vehicle control device

Abstract

The invention provides a vehicle control device that suppresses an increase in vibration of a vehicle. The purpose can be achieved by a control device for a vehicle provided with: a supercharger-equipped engine mounted on the front side; a transmission; and a wastegate valve that opens and closes an exhaust bypass passage connected to an exhaust passage of the engine by bypassing a turbine of the supercharger, the vehicle control device being provided with: an acquisition unit that acquires an engine speed and a target supercharging pressure when there is an acceleration request; when the engine speed is equal to or less than a predetermined speed and the target boost pressure is equal to or greater than a predetermined pressure, the prediction unit predicts that the vibration of the vehicle increases when the actual boost pressure increases to the target boost pressure at the engine speed. Predicting that the vibration of the vehicle is not increased under the condition that the engine speed is higher than the specified speed or the target supercharging pressure is lower than the specified pressure; and a slow change control unit that executes slow change processing.

Description

TECHNICAL FIELD

[0001] The present application relates to a control device for a vehicle. BACKGROUND

[0002] An engine with a supercharger is known (see, for example, Patent Document 1).

[0003] [Patent Document]

[0004] [Patent Document]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2007-205306. SUMMARY

[0006] [Problems to be Solved by the Invention]

[0007] In a case where an engine with a supercharger is mounted on a vehicle, depending on the configuration of the vehicle, the supercharging pressure increases in a state where the engine speed is low, and thus the vibration of the vehicle can increase.

[0008] Therefore, an object of the present application is to provide a control device for a vehicle that suppresses an increase in the vibration of the vehicle.

[0009] [Means for Solving the Problems]

[0010] The above object can be achieved by a control device for a vehicle having a supercharged engine mounted on a front side, a transmission mounted on a rear side and transmitting the power of the engine via a propeller shaft, and a waste gate valve that opens and closes an exhaust bypass passage connected to an exhaust passage of the engine around a turbine of the supercharger, wherein the control device for the vehicle includes an acquisition unit that acquires an engine speed and a target supercharging pressure in the presence of an acceleration request, a prediction unit that predicts that the vibration of the vehicle will increase in a case where the actual supercharging pressure rises to the target supercharging pressure at the engine speed, in a case where the engine speed is below a prescribed speed and the target supercharging pressure is above a prescribed pressure, and predicts that the vibration of the vehicle will not increase in a case where the actual supercharging pressure rises to the target supercharging pressure at the engine speed, in a case where the engine speed is higher than the prescribed speed or the target supercharging pressure is less than the prescribed pressure, and a gradual change control unit that performs a gradual change process of gently raising the actual supercharging pressure to the target supercharging pressure by gently lowering the opening degree of the waste gate valve, in a case where it is predicted that the vibration of the vehicle will increase, compared to a case where it is predicted that the vibration of the vehicle will not increase.

[0011] In addition, the above object can be achieved by a control device of a vehicle having: a front-mounted supercharged engine; a transmission mounted on a rear side, which is transmitted power of the engine via a propeller shaft; and an air bypass valve that opens and closes an intake bypass passage connected to an intake passage of the engine around a compressor of the supercharger, the control device of the vehicle including: an acquisition unit that acquires an engine speed and a target supercharging pressure in the presence of an acceleration request; a prediction unit that predicts that vibration of the vehicle will increase in a case where an actual supercharging pressure rises to the target supercharging pressure at the engine speed, in a case where the engine speed is equal to or lower than a prescribed speed and the target supercharging pressure is equal to or higher than a prescribed pressure, and predicts that the vibration of the vehicle will not increase in a case where the actual supercharging pressure rises to the target supercharging pressure at the engine speed, in a case where the engine speed is higher than the prescribed speed or the target supercharging pressure is lower than the prescribed pressure; and a gradual change control unit that performs gradual change processing in which the actual supercharging pressure is gradually raised to the target supercharging pressure by gradually lowering an opening degree of the air bypass valve, in a case where it is predicted that the vibration of the vehicle will increase, compared to a case where it is predicted that the vibration of the vehicle will not increase.

[0012] [Effects of Invention]

[0013] According to the present application, it is possible to provide a control device of a vehicle that suppresses an increase in vibration of the vehicle. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a schematic configuration view of a vehicle.

[0015] Figure 2 is a schematic configuration view of an engine.

[0016] Figure 3 A of FIG. 1 is a graph showing a magnitude of vibration of the vehicle in a case where an acceleration request is present and a target supercharging pressure is equal to or higher than a prescribed pressure P, Figure 3 B of FIG. 1 is a flowchart illustrating control performed by an ECU.

[0017] Figure 4 is a timing chart illustrating gradual change processing.

[0018] Figure 5 is a timing chart illustrating gradual change processing in a modified example. DETAILED DESCRIPTION

[0019] Figure 1is a schematic configuration view of a vehicle 1. The vehicle 1 includes an engine 10, a transmission shaft 40, a transmission 50, a drive shaft 60, drive wheels 70, and an electronic control unit (ECU) 100. The engine 10 is a running power source of the vehicle 1. The engine 10 is a gasoline engine, but is not limited thereto, and can be, for example, a diesel engine, or a hydrogen fuel engine. The transmission shaft 40 extends in a front-rear direction of the vehicle 1 and connects the engine 10 and the transmission 50. A torque tube that is a cover member covering a periphery of the transmission shaft 40 can be provided in the transmission shaft 40. Rotational power of the engine 10 is transmitted to the transmission 50 via the transmission shaft 40. The transmission 50 transmits rotational power of the transmission shaft 40 to the drive shaft 60. The transmission 50 is a transmission that reduces the rotation of the transmission shaft 40 at a prescribed reduction ratio and transmits the reduced rotation to the drive shaft 60. The drive wheels 70 rotate by the rotation of the drive shaft 60.

[0020] The engine 10 is mounted in an engine compartment on a front side of the vehicle 1. The transmission 50 is mounted on a rear side of the vehicle 1, for example, on a rear side of a passenger room. The vehicle 1 is a so-called FR vehicle. Therefore, the drive wheels 70 are rear wheels. The engine 10 and the transmission 50 are controlled by the ECU 100.

[0021] Figure 2 is a schematic configuration view of the engine 10. The engine 10 has a plurality of cylinders 11 (only one is illustrated in Figure 2 ) in a cylinder block. A piston 12 provided in the cylinder 11 is linked to a crankshaft 13 via a connecting rod 14. The connecting rod 14 converts a reciprocating motion of the piston 12 into a rotational motion of the crankshaft 13. A cylinder head is installed on an upper portion of the cylinder block. A combustion chamber 15 in which a spark plug 16 is disposed is formed between the cylinder head and an upper end of the piston 12. An intake passage 19 and an exhaust passage 20 are connected to an intake port 17 and an exhaust port 18, respectively, which are provided in correspondence with the combustion chamber 15.

[0022] A compressor 23A of a supercharger 23 is provided in the intake passage 19. A turbine 23B of the supercharger 23 is provided in the exhaust passage 20. Exhaust gas generated by combustion in the combustion chamber 15 of each cylinder is introduced into the turbine 23B of the supercharger 23 through an exhaust manifold. When the turbine 23B is operated by the introduced exhaust gas, the compressor 23A on the intake passage 19 side is linked, and air on the intake passage 19 side is compressed. The pressure in the intake passage 19, that is, the intake pressure, is increased by the compressed air, and air is efficiently filled into the combustion chamber 15 by the pressure.

[0023] In the intake passage 19, an air flow meter 92, an intake bypass passage 33, a supercharging pressure sensor 94, a throttle valve 22, and a throttle opening sensor 93 are provided from the upstream side thereof. The intake bypass passage 33 bypasses the compressor 23A. The air bypass valve 34 is provided in the intake bypass passage 33. The throttle valve 22 adjusts the intake air amount by changing the opening degree thereof. The intake passage 19 branches in the intake manifold provided downstream of the throttle valve 22, and the portions of the branch are connected to the respective combustion chambers 15. The in-cylinder injection valve 25 that injects fuel into the cylinder 11 is provided. The air flow meter 92, the throttle opening sensor 93, and the supercharging pressure sensor 94 will be described later.

[0024] In the exhaust passage 20, an exhaust bypass passage 35 that bypasses the turbine 23B is provided. The exhaust bypass valve 36 is provided in the exhaust bypass passage 35. The exhaust bypass valve 36 adjusts the supercharging pressure of the supercharger 23. The catalyst 29 that purifies exhaust gas is provided downstream of the exhaust bypass valve 36.

[0025] The engine 10 is provided with an intake valve 26 and an exhaust valve 27 that open and close the intake port 17 and the exhaust port 18, respectively, which are connected to the intake passage 19 and the exhaust passage 20, respectively. The intake valve 26 and the exhaust valve 27 perform opening and closing operations in response to the rotation of the intake-side camshaft and the exhaust-side camshaft that are drivingly coupled to the crankshaft 13. Thus, the intake valve 26 and the exhaust valve 27 are driven to be opened and closed in synchronization with the rotation of the crankshaft 13, that is, in correspondence with the reciprocating movement of each piston 12 at a predetermined timing.

[0026] The intake variable valve mechanism 26a changes the opening and closing timing of the intake valve 26 by changing the phase of the intake camshaft relative to the rotation of the crankshaft 13. The exhaust variable valve mechanism 27a changes the opening and closing timing of the exhaust valve 27 by changing the phase of the exhaust camshaft relative to the rotation of the crankshaft 13. Thus, it is possible to change the period during which both the intake valve 26 and the exhaust valve 27 are open, that is, the valve overlap period. The intake variable valve mechanism 26a and the exhaust variable valve mechanism 27a are hydraulic, but are not limited thereto.

[0027] The ECU 100 includes a central processing unit (CPU), a random access memory (RAM), a read only memory (ROM), and a storage device. The ECU 100 controls the engine 10 by executing a program stored in the ROM, the storage device. The ECU 100 is an example of a control device of the vehicle 1. The ECU 100 functionally realizes the acquisition section, the prediction section, and the gradual change control section by the CPU, the ROM, the RAM, and the storage device. The ECU 100 controls the fuel injection amount, the ignition timing, the opening degree of the throttle valve 22, the opening and closing timing of the intake valve 26 and the exhaust valve 27, each opening degree of the air bypass valve 34 and the exhaust bypass valve 36, and the like, in accordance with the operating state of the engine 10.

[0028] The ECU 100 performs prescribed calculations based on the detection signals of the various sensors described above. For example, the ECU 100 calculates the engine speed based on the detection signal of the crank angle sensor 90. The ECU 100 calculates the degree of opening of the accelerator pedal operated by the driver based on the detection signal of the accelerator opening sensor 91. The ECU 100 calculates the amount of air introduced into the combustion chamber 15, i.e., the intake air amount, based on the detection signal of the air flow meter 92. The ECU 100 calculates the degree of opening of the throttle valve 22 based on the detection signal of the throttle opening sensor 93. The ECU 100 calculates the pressure of the intake air pressurized by the compressor 23A, i.e., the actual supercharging pressure, based on the detection signal of the supercharging pressure sensor 94.

[0029] Figure 3 A of FIG. 10 is a graph showing the magnitude of the vibration of the vehicle 1 in the case where the acceleration request is present and the target supercharging pressure is a prescribed pressure P or more. Figure 3 A of FIG. 10 shows the magnitude of the vibration of the vehicle 1 when the engine speed is raised by the actual supercharging pressure being raised to the target supercharging pressure in a state where the engine speed is low, in the case where the acceleration request is present. The horizontal axis shows the engine speed, and the vertical axis shows the magnitude of the vibration of the vehicle 1. Figure 3 A of FIG. 10 shows the comparative example shown by the dashed line and the present embodiment shown by the solid line. The comparative example shows the case where the engine speed is less than a prescribed speed R and the actual supercharging pressure is raised to the target supercharging pressure. The present embodiment shows the case where the actual supercharging pressure is more gently raised to the target supercharging pressure than in the comparative example when the engine speed is less than the prescribed speed R.

[0030] In the comparative example, the vibration increases when the engine speed is less than the prescribed speed R. In a state where the engine speed is low, the actual supercharging pressure is raised to the target supercharging pressure, and the engine torque increases. Here, the transmission 50 resonates in a state where the engine speed is low. In the comparative example, the engine torque is high at the time of such resonance, and therefore the vibration of the vehicle 1 increases. In the present embodiment, in the case where the engine speed is less than the prescribed speed R and the target supercharging pressure is a prescribed pressure P or more, a gentle change process is executed in which the actual supercharging pressure is more gently raised to the target supercharging pressure than in the comparative example, as will be described later. Thus, in the present embodiment, the engine torque is maintained in a low state in a state where the engine speed is low. Therefore, the increase in the vibration of the vehicle 1 is suppressed.

[0031] Figure 3B is a flowchart illustrating the control executed by the ECU 100. The ECU 100 determines whether or not there is an acceleration request (step S1). In the case of NO in step S1, the present control ends. In the case of YES in step S1, the ECU 100 acquires the engine speed and the target supercharging pressure (step S2). The engine speed is calculated by the ECU 100 on the basis of the detection signal of the crank angle sensor 90. The target supercharging pressure is calculated by the ECU 100 in accordance with the operating state of the engine 10, the throttle opening degree. Step S2 is an example of the processing executed by the acquisition section.

[0032] Next, the ECU 100 predicts whether or not the vibration of the vehicle 1 increases on the basis of the engine speed and the target supercharging pressure (step S3). Specifically, in the case where the engine speed is equal to or lower than a prescribed speed R and the target supercharging pressure is equal to or higher than a prescribed pressure P, it is predicted that the vibration of the vehicle 1 will increase in the case where the actual supercharging pressure rises to the target supercharging pressure at the engine speed acquired in step S2. In the case where the engine speed is greater than the prescribed speed R or the target supercharging pressure is lower than the prescribed pressure P, it is predicted that the vibration of the vehicle 1 will not increase even in the case where the actual supercharging pressure rises to the target supercharging pressure at the engine speed acquired in step S2. Step S3 is an example of the processing executed by the prediction section. In addition, the prescribed speed R is higher than the idling speed, and the prescribed pressure P is higher than the supercharging pressure in the idling operating state.

[0033] In the case of NO in step S3, that is, in the case where it is predicted that the vibration of the vehicle 1 will not increase, the present control ends. In this case, for example, the ECU 100 immediately reduces the opening degree of the exhaust pressure relief valve 36 so as to make the actual supercharging pressure the target supercharging pressure. Thereby, the flow rate of the exhaust gas through the turbine 23B increases, and the actual supercharging pressure rises to the target supercharging pressure in advance. Thereby, the responsiveness of acceleration is ensured.

[0034] In the case of YES in step S3, that is, in the case where it is predicted that the vibration of the vehicle 1 will increase, the ECU 100 executes a gradual change process (step S4). The gradual change process is a process of gently raising the actual supercharging pressure to the target supercharging pressure as compared with the case where it is predicted that the vibration of the vehicle 1 will not increase. In the present embodiment, the gradual change process is executed by gently reducing the opening degree of the exhaust pressure relief valve 36 as compared with the case where it is predicted that the vibration of the vehicle 1 will not increase. "Gently reducing the opening degree" means making the reduction speed of the opening degree slower. In other words, by executing the gradual change process, the supercharging delay is enlarged as compared with the case where it is predicted that the vibration of the vehicle 1 will not increase. Step S4 is an example of the processing executed by the gradual change control section.

[0035] Figure 4 is a timing chart illustrating the gradual change process. Figure 4The progress of the engine rotation speed, the magnitude of the vibration of the vehicle 1, the supercharging pressure, the engine torque, and the opening degree of the exhaust pressure relief valve 36 is shown. Figure 4 The comparative example shown by the broken line and the present embodiment shown by the solid line are shown. In the comparative example, the gradual change processing is not performed. In the present embodiment, the gradual change processing is performed.

[0036] In the comparative example, when there is an acceleration request (time tO), the opening degree of the exhaust pressure relief valve 36 is immediately decreased, the actual supercharging pressure is increased to the target supercharging pressure, and the engine torque is increased to the target torque (time tl). Here, the engine rotation speed is less than the prescribed rotation speed R, and the actual supercharging pressure is the prescribed pressure P or more, so the vibration of the vehicle 1 can increase.

[0037] In the present embodiment, when there is an acceleration request (time tO), the opening degree of the exhaust pressure relief valve 36 is gradually decreased, the actual supercharging pressure is gradually increased, and the engine torque is also gradually increased. At the time when the engine rotation speed exceeds the prescribed rotation speed R (time t2), the actual supercharging pressure is increased to the vicinity of the target supercharging pressure, and the engine torque is also increased to the vicinity of the target torque. In this way, in the present embodiment, the actual supercharging pressure is gradually increased to the target supercharging pressure compared to the comparative example. Thereby, the increase in the vibration of the vehicle 1 is suppressed. Further, in the execution of the gradual change processing, the opening degree of the air bypass valve 34 is maintained constant.

[0038] [Modified Example]

[0039] Next, a modified example of the gradual change processing is described. In the modified example, the gradual change processing is performed by gradually decreasing the opening degree of the air bypass valve 34 compared to the case where it is predicted that the vibration of the vehicle 1 does not increase. Thereby, it is possible to gradually increase the flow rate of the intake air through the compressor 23A and gradually increase the actual supercharging pressure to the target supercharging pressure.

[0040] Figure 5 is a time chart illustrating the gradual change processing in the modified example. When there is an acceleration request (time tO), the opening degree of the air bypass valve 34 is gradually decreased, the actual supercharging pressure is gradually increased, and the engine torque is also gradually increased. At the time when the engine rotation speed exceeds the prescribed rotation speed R (time t2), the actual supercharging pressure is increased to the vicinity of the target supercharging pressure, and the engine torque is also increased to the vicinity of the target torque. In this way, in the present modified example, the actual supercharging pressure is gradually increased to the target supercharging pressure compared to the comparative example. Thereby, the increase in the vibration of the vehicle 1 is suppressed. Further, in the execution of the gradual change processing in the modified example, the opening degree of the exhaust pressure relief valve 36 is maintained constant.

[0041] It is also possible to perform the gradual change processing by gradually decreasing each of the opening degrees of the air bypass valve 34 and the exhaust pressure relief valve 36 compared to the case where it is predicted that the vibration of the vehicle 1 does not increase.

[0042] In addition, the ECU 100 can also perform a gradual change process by controlling the intake variable valve mechanism 26a and the exhaust variable valve mechanism 27a to gradually increase the valve overlap period more gently than in a case where the vibration of the vehicle 1 is predicted not to increase.

[0043] In addition, the shape, number, and size of the blades of the turbine 23B can be changed in a manner in which the turbine efficiency decreases and the actual boost pressure is less than the prescribed pressure P when the engine speed is below the prescribed speed R.

[0044] The above describes an embodiment of the present application, but the present application is not limited to this particular embodiment and various modifications and changes can be made within the scope of the gist of the present application as recited in the claims.

[0045] [Legend]

[0046] 1 vehicle

[0047] 10 engine

[0048] 19 intake passage

[0049] 20 exhaust passage

[0050] 23 supercharger

[0051] 23A compressor

[0052] 23B turbine

[0053] 33 intake bypass passage

[0054] 34 air bypass valve

[0055] 35 exhaust bypass passage

[0056] 36 exhaust pressure relief valve

[0057] 100 ECU (control device, acquisition section, prediction section, gradual change control section)

Claims

1. A control device of a vehicle that includes: an engine with a supercharger mounted on a front side; a transmission mounted on a rear side that transmits power of the engine via a propeller shaft; and a wastegate valve that opens and closes an exhaust bypass passage connected to an exhaust passage of the engine, bypassing a turbine of the supercharger, the control device of the vehicle comprising: an acquisition unit that acquires an engine speed and a target supercharging pressure in the presence of an acceleration request; a prediction unit that predicts that vibration of the vehicle will increase if an actual supercharging pressure rises to the target supercharging pressure at the engine speed in the case where the engine speed is below a prescribed speed and the target supercharging pressure is above a prescribed pressure, and predicts that vibration of the vehicle will not increase if the actual supercharging pressure rises to the target supercharging pressure at the engine speed in the case where the engine speed is higher than the prescribed speed or the target supercharging pressure is less than the prescribed pressure; and a gradual change control unit that performs gradual change processing in which the actual supercharging pressure is gradually raised to the target supercharging pressure by gradually lowering an opening degree of the wastegate valve in the case where it is predicted that vibration of the vehicle will increase, compared to the case where it is predicted that vibration of the vehicle will not increase.

2. A control device of a vehicle that includes: an engine with a supercharger mounted on a front side; and an air bypass valve that opens and closes an intake bypass passage connected to an intake passage of the engine, bypassing a compressor of the supercharger, wherein the control device of the vehicle comprises: an acquisition unit that acquires an engine speed and a target supercharging pressure in the presence of an acceleration request; a prediction unit that predicts that vibration of the vehicle will increase if an actual supercharging pressure rises to the target supercharging pressure at the engine speed in the case where the engine speed is below a prescribed speed and the target supercharging pressure is above a prescribed pressure, and predicts that vibration of the vehicle will not increase if the actual supercharging pressure rises to the target supercharging pressure at the engine speed in the case where the engine speed is higher than the prescribed speed or the target supercharging pressure is less than the prescribed pressure; and a gradual change control unit that performs gradual change processing in which the actual supercharging pressure is gradually raised to the target supercharging pressure by gradually lowering an opening degree of the air bypass valve in the case where it is predicted that vibration of the vehicle will increase, compared to the case where it is predicted that vibration of the vehicle will not increase. ​ ​ wherein ​ ​ ​ ​ ​ ​ The transmission is mounted on the rear side and transmits the power of the engine via a propeller shaft. ​ ​ ​ ​ ​ ​ ​ ​

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