Vehicle control system

Abstract

To suppress poor ventilation of a crankcase.SOLUTION: An electronic control unit 50 is a control device of a vehicle with a supercharged engine 10 comprising a blowby gas recirculation device that individually ventilates a crankcase by suction of blowby gas under intake negative pressure during NA operation and by expulsion of blowby gas under boost pressure during supercharged operation. When a ventilation stagnation state continues, in which an intake pipe pressure of the supercharged engine 10 is close to atmospheric pressure, the electronic control unit executes stagnation resolution control to change the operation conditions of the supercharged engine 10 to operation conditions that maintain driving force of the vehicle and resolves the ventilation stagnation state.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a control device for a vehicle equipped with a supercharged engine.

Background Art

[0002] As a device applied to an engine mounted on a vehicle, there is a blow-by gas ventilation device that ventilates the blow-by gas in the crankcase. As a blow-by gas ventilation device, there is one that performs ventilation by sucking blow-by gas into the intake air by the intake negative pressure formed by the throttle throttle. In the case of a supercharged engine, during supercharged operation, since intake negative pressure is not formed, blow-by gas ventilation using the above intake negative pressure cannot be performed. On the other hand, Patent Document 1 describes a blow-by gas ventilation device that performs ventilation by pushing out the blow-by gas in the crankcase by the supercharging pressure.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] If the above ventilation by intake negative pressure and ventilation by supercharging pressure are used in combination, blow-by gas ventilation can be performed both during natural intake operation and during supercharged operation of a supercharged engine. However, even in such a case, when the intake pipe pressure is near atmospheric pressure, neither ventilation by intake negative pressure nor ventilation by supercharging pressure can be effectively performed. Therefore, if the state where the intake pipe pressure is near atmospheric pressure continues, ventilation of the crankcase becomes insufficient.

Means for Solving the Problems

[0005] A vehicle control device that solves the above problems is a device that controls a vehicle equipped with a supercharged engine, wherein the supercharged engine comprises a compressor installed in the intake passage, a throttle valve installed in the intake passage downstream of the compressor, and a blow-by gas recirculation device that recirculates blow-by gas from the crankcase into the intake air, wherein the blow-by gas recirculation device comprises a first passage that connects the intake passage downstream of the throttle valve to the crankcase, a second passage that connects the intake passage downstream of the compressor and upstream of the throttle valve to the crankcase, and a third passage that connects the intake passage upstream of the compressor to the crankcase, and if the ventilation stagnation state of the supercharged engine continues, the control device executes stagnation-resolving control to change the operating conditions of the supercharged engine to operating conditions that maintain the driving force of the vehicle and resolve the ventilation stagnation state. The aforementioned ventilation stagnation state is a condition in which the intake pipe pressure of the supercharged engine is near atmospheric pressure. [Effects of the Invention]

[0006] The control device in the above-mentioned vehicle has the effect of suppressing poor ventilation in the crankcase of the turbocharged engine. [Brief explanation of the drawing]

[0007] [Figure 1] This diagram schematically shows the configuration of a turbocharged engine mounted on a vehicle to which one embodiment of a vehicle control device is applied. [Figure 2] This diagram shows the gas flow in a blow-by gas recirculation device installed in the turbocharged engine described above, during naturally aspirated operation. [Figure 3] This diagram shows the gas flow during turbocharging operation in a blow-by gas recirculation device installed in the turbocharged engine described above. [Figure 4] This graph shows the relationship between hydrogen concentration in the crankcase and intake manifold pressure in the turbocharged engine described above. [Figure 5]This diagram schematically shows the configuration of the control device of the above-mentioned vehicle. [Figure 6] This is a flowchart of the stall-resolving control routine executed by the control unit of the above vehicle. [Modes for carrying out the invention]

[0008] Below, one embodiment of the vehicle control device will be described in detail with reference to Figures 1 to 6. <Configuration of a supercharged engine> First, with reference to Figure 1, the configuration of the supercharged engine 10 mounted on the vehicle targeted for control in this embodiment will be described. The supercharged engine 10 shown in Figure 1 is a hydrogen engine that uses hydrogen as fuel. In a hydrogen engine, combustible hydrogen may be contained in the blow-by gas. Therefore, hydrogen engines require higher blow-by gas ventilation performance than gasoline engines or diesel engines.

[0009] The supercharged engine 10 includes a cylinder block 11. Inside the cylinder block 11 are multiple cylinders 12. Figure 1 shows only one of the multiple cylinders 12. Each cylinder 12 houses a piston 13 that is reciprocally movable. Above the piston 13 in the cylinder 12 is a combustion chamber 17 for burning hydrogen. An oil pan 14 for storing oil is attached to the lower part of the cylinder block 11. Below the cylinders 12 inside the cylinder block 11 is a crankcase 15. A cylinder head 16 is attached to the upper part of the cylinder block 11. Inside the cylinder head 16, each cylinder 12 has its own individual intake port 18 and exhaust port 19. A head cover 16A is attached to the upper part of the cylinder head 16. Inside the upper part of the cylinder head 16, covered by the head cover 16A, is a valve train chamber 20 housing the valve train mechanism.

[0010] The supercharged engine 10 includes an intake passage 21, which is the passage for introducing air into the combustion chamber 17, and an exhaust passage 22, which is the passage for discharging exhaust from the combustion chamber 17. The intake passage 21 is equipped with an air cleaner 23 for filtering dust and other particles from the air. A compressor 24 is installed in the intake passage 21 downstream of the air cleaner 23. The compressor 24, together with a turbine 25 installed in the exhaust passage 22, constitutes a turbocharger. An intercooler 26 is installed in the intake passage 21 downstream of the compressor 24. The intercooler 26 is a heat exchanger for cooling the air that has become hot due to compression by the compressor 24. A throttle valve 27 is installed in the intake passage 21 downstream of the intercooler 26. The throttle valve 27 is a valve for adjusting the flow rate of air sent to the combustion chamber 17 through the intake passage 21. The intake passage 21 is branched separately for each cylinder 12 in the intake manifold 28, which is located downstream of the throttle valve 27. The intake manifold 28 is connected to the combustion chamber 17 through the intake port 18.

[0011] Furthermore, the supercharged engine 10 is equipped with an injector 29, a hydrogen tank 30, and a pressure regulating device 31. The pressure regulating device 31 regulates the pressure of the hydrogen in the hydrogen tank 30 and supplies it to the injector 29. The injector 29 injects hydrogen into the air used for combustion in the combustion chamber 17. In the case of Figure 1, the injector 29 is installed to inject hydrogen into the intake port 18, but the injector 29 may also be installed to inject hydrogen into the combustion chamber 17.

[0012] The supercharged engine 10 includes an intake valve 32 that opens and closes an intake port 18 relative to the combustion chamber 17, and an exhaust valve 33 that opens and closes an exhaust port 19 relative to the combustion chamber 17. The supercharged engine 10 also includes a variable valve timing mechanism 34 that varies the valve timing of the intake valve 32.

[0013] The supercharged engine 10 is equipped with an exhaust gas recirculation system that recirculates a portion of the exhaust gas into the intake air. The exhaust gas recirculation system comprises an EGR (Exhaust Gas Recirculation) passage 35, an EGR cooler 36, and an EGR valve 37. The EGR passage 35 is a passage that connects the intake air passage 21 and the exhaust air passage 22. The EGR cooler 36 is a heat exchanger that cools the exhaust gas that is recirculated into the intake air through the EGR passage 35. The EGR valve 37 is a valve that adjusts the amount of exhaust gas recirculated. The amount of exhaust gas recirculation represents the flow rate of the exhaust gas that is recirculated into the intake air through the EGR passage 35.

[0014] <Configuration of blow-by gas recirculation system> The supercharged engine 10 is further equipped with a blow-by gas recirculation device. The blow-by gas recirculation device is a device that ventilates the crankcase 15 by recirculating the blow-by gas in the crankcase 15 into the intake air. The blow-by gas recirculation device has three passages, a first passage R1, a second passage R2, and a third passage R3, which connect the crankcase 15 and the intake passage 21.

[0015] The first passage R1 is a passage that connects the portion of the intake passage 21 downstream of the throttle valve 27 to the crankcase 15. The first passage R1 consists of a blow-by gas passage 40, a head-side separator 41, a first check valve 42, a first PCV hose 43, and a block-side separator 44. The head-side separator 41 and the block-side separator 44 are separators that separate oil mist from the blow-by gas flowing through the first passage R1. The head-side separator 41 is mounted inside the head cover 16A. The blow-by gas passage 40 is a passage that connects the crankcase 15 and the head-side separator 41 by passing through the inside of the cylinder block 11 and the cylinder head 16. The block-side separator 44 is provided in the middle of the blow-by gas passage 40 in the cylinder block 11. The first PCV hose 43 is a hose that connects the head-side separator 41 and the intake manifold 28. The first check valve 42 is a valve that allows gas to flow from the inside of the crankcase 15 through the first passage R1 to the intake passage 21, while restricting gas flow from the intake passage 21 through the first passage R1 to the inside of the crankcase 15. The first check valve 42 is installed at the connection point of the first PCV hose 43 to the head-side separator 41. In this embodiment, the head-side separator 41 and the block-side separator 44 correspond to the first separator that separates oil mist from the gas flowing through the first passage R1.

[0016] The second passage R2 is a passage that connects a portion of the intake passage 21 downstream of the compressor 24 to the crankcase 15. In the case of FIG. 1, the second passage R2 is configured to connect the intake manifold 28 and the crankcase 15. The second passage R2 is constituted by the second PCV hose 45 and the second check valve 46. The second PCV hose 45 is a hose that connects the crankcase 15 and the intake manifold 28. The second check valve 46 is a valve that allows the flow of gas from the intake passage 21 through the second passage R2 into the crankcase 15, while restricting the flow of gas from the inside of the crankcase 15 through the second passage R2 to the intake passage 21. The second check valve 46 is installed at the connection portion of the second PCV hose 45 to the crankcase 15.

[0017] The third passage R3 is a passage that connects a portion of the intake passage 21 upstream of the compressor 24 to the crankcase 15. The third passage R3 is constituted by the oil return passage 47, the valve operating chamber 20, the second separator 48, and the third PCV hose 49. The oil return passage 47 is a passage that passes through the inside of the cylinder block 11 and the cylinder head 16 and connects the valve operating chamber 20 and the crankcase 15. The oil return passage 47 functions as a passage for returning oil from the valve operating chamber 20 to the oil pan 14, while also functioning as a passage for allowing gas to flow between the valve operating chamber 20 and the crankcase 15. The second separator 48 is a separator that separates the oil mist in the blow-by gas flowing through the third passage R3. The second separator 48 is installed inside the head cover 16A. The third PCV hose 49 is a hose that connects a portion of the intake passage 21 downstream of the air cleaner 23 and upstream of the compressor 24 to the second separator 48.

[0018] <Ventilation operation of the crankcase> Next, referring to FIGS. 2 to 4, the ventilation operation of the crankcase 15 by the blow-by gas reflux device will be described. The white arrows shown in FIGS. 2 and 3 indicate the flow direction of air in the blow-by gas reflux device. Also, the arrows painted with hatching shown in FIGS. 2 and 3 indicate the flow direction of blow-by gas in the blow-by gas reflux device. In the following description, the intake pressure in the intake manifold 28 of the supercharged engine 10 is referred to as the intake pipe pressure PM. And in the following description, the operation of the supercharged engine 10 in a state where the intake pipe pressure PM is negative, that is, a state lower than the atmospheric pressure, is described as NA (Natural Aspiration) operation. Also, the operation of the supercharged engine 10 in a state where the intake pipe pressure PM is positive, that is, a state higher than the atmospheric pressure, is described as supercharged operation.

[0019] FIG. 2 shows the state of the blow-by gas reflux device during NA operation. During NA operation, the inside of the intake manifold 28 becomes negative pressure. The inside of the crankcase 15 is connected to the intake manifold 28 through the first passage R1. Further, the first check valve 42 installed in the first passage R1 is configured to allow the flow of gas from the inside of the crankcase 15 through the first passage R1 toward the intake passage 21. On the other hand, the inside of the crankcase 15 is connected through the third passage R3 to a portion upstream of the compressor 24 in the intake passage 21. Therefore, at this time, air is introduced into the inside of the crankcase 15 through the third passage R3, and the blow-by gas in the crankcase 15 is sucked into the intake manifold 28 through the first passage R1.

[0020] Figure 3 shows the state of the blow-by gas recirculation device during supercharging operation. During supercharging operation, the portion of the intake passage 21 downstream of the compressor 24 becomes positive pressure. The second passage R2 is provided to connect the crankcase 15 with the intake manifold 28, which is the positive pressure portion of the intake passage 21. The second check valve 46 installed in the second passage R2 is configured to allow gas flow from the intake passage 21 to the inside of the crankcase 15 through the second passage R2. Therefore, air is introduced into the crankcase 15 through the second passage R2 at this time. Then, the blow-by gas inside the crankcase 15 is sent to the intake passage 21 through the third passage R3 by the introduced positive pressure air.

[0021] Figure 4 shows the relationship between hydrogen concentration in the crankcase 15 and intake manifold pressure PM. Figure 4 shows the results of measuring the hydrogen concentration in the crankcase 15 under various intake manifold pressure PM conditions after operating the supercharged engine 10 for a predetermined time while maintaining constant intake manifold pressure PM and engine rotational speed NE. When the intake manifold pressure PM is lower than atmospheric pressure, the crankcase 15 is ventilated in the manner shown in Figure 2. When it is higher than the intake manifold pressure PM, the crankcase 15 is ventilated in the manner shown in Figure 3. However, when the intake manifold pressure PM is near atmospheric pressure, neither the manner in Figure 2 nor Figure 3 can provide sufficient ventilation. Therefore, if the intake manifold pressure PM remains near atmospheric pressure, the hydrogen concentration in the crankcase 15 increases due to insufficient ventilation. In Figure 4, the range R of intake manifold pressure PM where ventilation is insufficient is indicated by dots. In the following explanation, the state in which the ventilation capacity of the crankcase 15 is reduced due to the intake manifold pressure PM being near atmospheric pressure will be described as a ventilation stagnation state.

[0022] <Configuration of the vehicle's control system> The vehicle control device of this embodiment is applied to a vehicle equipped with a supercharged engine 10 that has a blow-by gas recirculation device as described above. This vehicle control device avoids a situation in which the intake manifold pressure PM remains near atmospheric pressure, resulting in insufficient ventilation of the crankcase 15, by performing a stagnation elimination control described later.

[0023] Next, with reference to Figure 5, the configuration of the vehicle control device of this embodiment will be described. The control device includes an electronic control unit 50. The electronic control unit 50 has a processor 51 and a memory 52. ​​The memory 52 stores various programs and data for vehicle control. The processor 51 is a processing circuit that reads and executes programs from the memory 52.

[0024] The electronic control unit 50 receives detection signals from various sensors installed in different parts of the vehicle. These sensors include an airflow meter 53, an intake manifold pressure sensor 54, a crank angle sensor 55, an accelerator pedal sensor 56, and a vehicle speed sensor 57. The airflow meter 53 is a sensor that detects the flow rate of intake air (hereinafter referred to as intake air volume GA) flowing through the intake passage 21 of the supercharged engine 10. The intake manifold pressure sensor 54 is a sensor that detects the intake manifold pressure PM of the supercharged engine 10. The crank angle sensor 55 is a sensor that detects the crank angle of the supercharged engine 10. The crank angle represents the rotational phase of the crankshaft, which is the output shaft of the supercharged engine 10. The accelerator pedal sensor 56 is a sensor that detects the amount the driver of the vehicle presses down on the accelerator pedal (hereinafter referred to as accelerator pedal depression ACC). The vehicle speed sensor 57 is a sensor that detects the vehicle's driving speed (hereinafter referred to as vehicle speed V).

[0025] The electronic control unit 50 controls the throttle valve 27, injectors 29, variable valve timing mechanism 34, EGR valve 37, etc. of the supercharged engine 10 based on the detection results of these sensors. Specifically, the electronic control unit 50 calculates the operating amounts for the throttle valve 27, injectors 29, variable valve timing mechanism 34, EGR valve 37, etc., based on the detection results of each sensor. Then, the electronic control unit 50 drives the throttle valve 27, injectors 29, variable valve timing mechanism 34, EGR valve 37, etc., based on the calculated operating amounts. In this way, the electronic control unit 50 controls the operating state of the supercharged engine 10 by adjusting the air-fuel ratio of the mixture burned in the combustion chamber 17, the amount of exhaust gas recirculation, the valve timing of the intake valve 32, etc. Furthermore, the electronic control unit 50 controls the vehicle's gear changes by adjusting the gear ratio of the transmission 38, which is provided in the power transmission path from the supercharged engine 10 to the drive wheels 39, based on the detection results of each sensor.

[0026] <Stagnation Resolution Control> Furthermore, as part of the vehicle control, the electronic control unit 50 performs stagnation-relieving control to resolve the aforementioned ventilation stagnation state. In the following description, the control of the supercharged engine 10, transmission 38, etc., performed by the electronic control unit 50 when stagnation-relieving control is not performed will be referred to as normal vehicle control.

[0027] Figure 6 shows the processing procedure of the electronic control unit 50 for determining whether to perform stall-resolving control or normal vehicle control. The electronic control unit 50 repeatedly executes the process shown in Figure 6 at predetermined control cycles while the supercharged engine 10 is running. In the following explanation and in Figure 5, "S" represents a step in the processing performed by the electronic control unit 50.

[0028] When the electronic control unit 50 starts the process shown in Figure 6, it first acquires the engine speed NE and the required load ratio KL* in S100. The engine speed NE is the rotational speed of the crankshaft, which is the output shaft of the supercharged engine 10. The electronic control unit 50 determines the engine speed NE based on the detection signal from the crank angle sensor 55. The required load ratio KL* is the required value of the intake air filling rate η of the combustion chamber 17. The electronic control unit 50 determines the required load ratio KL* based on the detection signal from the accelerator pedal sensor 56, the calculated value of the engine speed NE, etc. In normal control when stagnation resolution control is not performed, the electronic control unit 50 determines the operating amounts of the throttle valve 27, variable valve timing mechanism 34, EGR valve 37, etc., so that the intake air filling rate η of the combustion chamber 17 is equal to the required load ratio KL*.

[0029] In the following step S102, the electronic control unit 50 determines whether the supercharged engine 10 is in a ventilation stagnation state. In making the determination in S102, the electronic control unit 50 estimates the intake manifold pressure PM when the supercharged engine 10 is operated with the intake air filling rate η of the combustion chamber 17 equal to the required load rate KL* by performing normal vehicle control. The electronic control unit 50 then determines that the supercharged engine 10 is in a ventilation stagnation state if the estimated intake manifold pressure PM is within a predetermined range including atmospheric pressure.

[0030] If the supercharged engine 10 is not in a ventilation stagnation state (S102: NO), the electronic control unit 50 resets the value of counter C to "0" in S104. Then, the electronic control unit 50 performs normal vehicle control (S106).

[0031] In contrast, if the supercharged engine 10 is in a ventilation stagnation state (S102:YES), the electronic control unit 50 increments counter C in S108. Subsequently, in S110, the electronic control unit 50 determines whether the value of counter C is above a predetermined threshold. If the electronic control unit 50 determines that the value of counter C is below the threshold (S110:NO), it performs normal vehicle control (S106). In contrast, if the electronic control unit 50 determines that the value of counter C is above the threshold (S110:YES), it performs stagnation resolution control instead of normal vehicle control (S112).

[0032] Stagnation-relieving control is a control that changes the operating conditions of the supercharged engine 10 to operating conditions that resolve the ventilation stagnation state while maintaining the vehicle's driving force at the same magnitude as when normal vehicle control is performed. Stagnation-relieving control is performed, for example, by performing one of the following processes (A) to (D), or a combination of two or more of these processes.

[0033] Each process (A) to (D) may be implemented to resolve the ventilation stagnation by increasing the intake manifold pressure PM, or to resolve the ventilation stagnation by decreasing the intake manifold pressure PM. The choice of which method to adopt should be determined by considering the trade-offs associated with implementing the stagnation-resolving control, such as a decrease in the fuel efficiency or exhaust performance of the turbocharged engine 10.

[0034] Process (A) is a process that adjusts the air-fuel ratio of the mixture burned in the supercharged engine 10. When the vehicle is running steadily with the vehicle speed V and the gear ratio of the transmission 38 constant, the driving force of the vehicle can be maintained by keeping the output of the supercharged engine 10 constant. When the air-fuel ratio changes, the thermal efficiency of the supercharged engine 10 changes. Therefore, in order to change the air-fuel ratio while maintaining the output of the supercharged engine 10, it is necessary to change the intake air charge rate η. Then, the intake manifold pressure PM changes due to the change in the intake air charge rate η. Thus, by adjusting the air-fuel ratio to a value different from that in the case of normal vehicle control while maintaining the output of the supercharged engine 10, the ventilation stagnation state can be eliminated. Such air-fuel ratio adjustments can be made, for example, by adjusting the opening degree of the throttle valve 27.

[0035] Process (B) is a process that adjusts the amount of exhaust gas recirculated into the intake air by the exhaust gas recirculation device. The exhaust gas recirculation device introduces exhaust gas to the portion of the intake passage 21 downstream of the throttle valve 27. By introducing exhaust gas to this portion, the intake manifold pressure PM increases. Therefore, by changing the amount of exhaust gas recirculation while maintaining the amount of air introduced into the combustion chamber 17, the intake manifold pressure PM can be changed while maintaining the output of the supercharged engine 10. This adjustment of the amount of exhaust gas recirculation can be done by changing the opening of the throttle valve 27 and the EGR valve 37.

[0036] Process (C) is a process of adjusting the valve timing of the intake valve 32. When the valve timing of the intake valve 32 changes, the intake efficiency of the combustion chamber 17 changes. Therefore, the intake manifold pressure PM at which the intake filling rate η of the combustion chamber 17 is constant, that is, the intake manifold pressure PM at which the output of the supercharged engine 10 is constant, changes depending on the valve timing of the intake valve 32. Thus, by adjusting the valve timing of the intake valve 32, the intake manifold pressure PM can be changed while maintaining the output of the supercharged engine 10.

[0037] Process (D) is a process that adjusts the gear ratio of the transmission 38. Changing the gear ratio of the transmission 38 changes the operating point of the supercharged engine 10 in which the vehicle's driving force can be maintained. This change in the operating point changes the intake manifold pressure PM of the supercharged engine 10. Therefore, by adjusting the gear ratio of the transmission 38, the intake manifold pressure PM can be changed while maintaining the output of the supercharged engine 10.

[0038] <Effects and Effects of the Embodiment> The operation and effects of this embodiment will now be described. In the process shown in Figure 6, the electronic control unit 50 determines whether or not the supercharged engine 10 enters a ventilation stagnation state when normal vehicle control is performed (S102). A ventilation stagnation state is a condition in which the intake manifold pressure PM of the supercharged engine 10 is near atmospheric pressure.

[0039] The electronic control unit 50 increments the value of counter C if it determines that a ventilation stagnation state has occurred (S102:YES) (S104), while resetting it if it determines that there is no ventilation stagnation state (S102:NO) (S108). The value of counter C thus operated represents the duration of the ventilation stagnation state. If the value of counter C is above a predetermined threshold (S110:YES), the electronic control unit 50 performs stagnation-resolving control instead of normal vehicle control (S112). After the start of stagnation-resolving control, if the electronic control unit 50 determines that a ventilation stagnation state will not occur even if normal vehicle control is performed (S102:NO), it returns to normal vehicle control (S106).

[0040] As described above, the blow-by gas recirculation device can ventilate the crankcase 15 when the turbocharged engine 10 is running naturally aspirated (NA) or turbocharged. However, the ventilation capacity decreases when the intake manifold pressure PM is near atmospheric pressure. If this ventilation stagnation continues, the ventilation of the crankcase 15 will become insufficient.

[0041] If the ventilation stagnation state persists for a certain period of time or longer, the electronic control unit 50 will perform stagnation-resolving control instead of normal vehicle control. When stagnation-resolving control is performed, the operating conditions of the supercharged engine 10 are changed so that the ventilation stagnation state is resolved while maintaining the vehicle's driving force. Subsequently, the electronic control unit 50 will continue the stagnation-resolving control until the ventilation stagnation state does not occur again even when the vehicle returns to normal vehicle control.

[0042] The vehicle control measures of this embodiment described above can achieve the following effects. (1) The turbocharged engine 10 mounted on the vehicle controlled by the control device of this embodiment is equipped with a blow-by gas recirculation device that can ventilate the crankcase 15 in both naturally aspirated (NA) operation and turbocharged operation. However, when the intake manifold pressure PM is near atmospheric pressure, the turbocharged engine 10 enters a ventilation stagnation state in which it cannot perform sufficient ventilation. The electronic control unit 50 executes stagnation resolution control when the ventilation stagnation state persists. Stagnation resolution control is a control that changes the operating conditions of the turbocharged engine 10 to operating conditions in which the driving force of the vehicle is maintained and the ventilation stagnation state is resolved. When stagnation resolution control is started, the ventilation stagnation state of the turbocharged engine 10 is resolved. Therefore, the vehicle control device of this embodiment has the effect of suppressing poor ventilation of the crankcase 15 of the turbocharged engine 10. In the stagnation resolution control, the operating conditions of the supercharged engine 10 can be changed, for example, by adjusting the air-fuel ratio, adjusting the amount of exhaust gas recirculation, adjusting the valve timing of the intake valve 32, or adjusting the gear ratio of the transmission 38.

[0043] (2) The blow-by gas recirculation device of the supercharged engine 10 includes a first passage R1, a second passage R2, a third passage R3, a first check valve 42, and a second check valve 46. The first passage R1 is a passage that connects the portion of the intake passage 21 downstream of the throttle valve 27 to the crankcase 15. The second passage R2 is a passage that connects the portion of the intake passage 21 downstream of the intercooler 26 to the crankcase 15. The third passage R3 is a passage that connects the portion of the intake passage 21 upstream of the compressor 24 to the crankcase 15. The first check valve 42 is a valve that allows the flow of gas from the crankcase 15 to the intake passage 21 through the first passage R1, while restricting the flow of gas from the intake passage 21 to the inside of the crankcase 15 through the first passage R1. The second check valve 46 is a valve that allows gas to flow from the intake passage 21 to the crankcase 15 through the second passage R2, while restricting gas flow from the crankcase 15 to the intake passage 21 through the second passage R2. This blow-by gas recirculation device can ventilate the blow-by gas from the crankcase 15 in both naturally aspirated and supercharged operation of the supercharged engine 10.

[0044] (Other embodiments) This embodiment can be implemented with the following modifications. This embodiment and the following modifications can be combined with each other to the extent that they do not contradict each other technically.

[0045] - Any process that can change the operating conditions of the turbocharged engine 10 to resolve the ventilation stagnation while maintaining the vehicle's driving force may be used to perform stagnation resolution control by processes other than those described above (A) to (D). For example, it is possible to perform stagnation resolution control by adjusting the ignition timing of the turbocharged engine 10. In addition, in the case of a hybrid vehicle equipped with a motor as a drive source in addition to the turbocharged engine 10, stagnation resolution control can be performed by adjusting the power distribution ratio between the turbocharged engine 10 and the motor.

[0046] In the above embodiment, after the start of the stagnation resolution control, the electronic control unit 50 terminated the stagnation resolution control when the supercharged engine 10 no longer entered a ventilation stagnation state even when normal vehicle control was performed. The conditions for terminating such stagnation resolution control may be changed as appropriate. For example, the stagnation resolution control may be terminated after a certain period of time has elapsed since the start of the stagnation resolution control. Alternatively, the stagnation resolution control may be terminated when the cumulative intake air volume, cumulative fuel injection volume, or vehicle mileage of the supercharged engine 10 exceeds a predetermined threshold after the start of the stagnation resolution control.

[0047] In S102 of Figure 6, it was determined whether the turbocharged engine 10 would enter a ventilation stagnation state under normal vehicle control conditions, based on the engine rotational speed NE and the required load factor KL*. In S102, it may also be determined whether the turbocharged engine 10 is currently in a ventilation stagnation state. Such a determination can be made based on the detection result of the intake manifold pressure sensor 54. Alternatively, a similar determination can be made based on an estimated value of the intake manifold pressure PM based on the detection results of other sensors.

[0048] The configuration of the blow-by gas recirculation device may be modified as appropriate. For example, the intake side of the second passage R2 may be connected to a part of the intake passage 21 downstream of the compressor 24, other than the intake manifold 28. Furthermore, some or all of the first PCV hose 43, the second PCV hose 45, and the third PCV hose 49 may be replaced with metal piping.

[0049] The supercharged engine 10 may be a supercharged engine other than a hydrogen engine, such as a gasoline engine or a diesel engine. In the case of an engine with multiple banks, such as a V-type engine, and a compressor, the blow-by gas recirculation device of the above embodiment may be provided individually for each bank. [Explanation of Symbols]

[0050] 10 Supercharged engine 11 Cylinder block 12 cylinders 13 pistons 14 Oil pan 15 Crankcase 16 Cylinder head 16A Headcover 17 Combustion chamber 18 intake ports 19 Exhaust Ports 20 Valve chamber 21 Intake passage 22 Exhaust passage 23 Air Cleaner 24 Compressors 25 Turbine 26 Intercooler 27 Throttle valve 28 Intake Manifold 29 Injectors 30 hydrogen tanks 31 Pressure Regulating Device 32 Intake valves 33 Exhaust valve 34 Variable valve timing mechanism 35 EGR passage 36 EGR cooler 37 EGR valve 40 Blow-by gas passage 41 Head-side separator 42 First check valve 43. First PCV hose 44 Block-side separator 45. Second PCV hose 46. ​​Second check valve 47 Oil return passage 48. Second Separator 49. Third PCV hose 50 Electronic control units 51 processors 52 memory 53 Airflow Meter 54 Intake pipe pressure sensor 55 Crank angle sensor 56. Accelerator pedal sensor 57 Vehicle speed sensor R1 First Path R2 Second Path R3 Third Path

Claims

1. A control device for a vehicle equipped with a supercharged engine, The supercharged engine comprises a compressor installed in the intake passage, a throttle valve installed in the intake passage downstream of the compressor, and a blow-by gas recirculation device that recirculates blow-by gas from the crankcase into the intake. The blow-by gas recirculation device comprises a first passage connecting the portion of the intake passage downstream of the throttle valve to the crankcase, a second passage connecting the portion of the intake passage downstream of the compressor to the crankcase, and a third passage connecting the portion of the intake passage upstream of the compressor to the crankcase. The control device is The intake manifold pressure is estimated when the supercharged engine is operated with the intake air filling rate of the combustion chamber equal to the required load rate. If the estimated inspiratory tube pressure is near atmospheric pressure, it is determined that ventilation is stagnant. If the aforementioned ventilation stagnation state persists, a stagnation-resolving control is performed to change the operating conditions of the supercharged engine to operating conditions that maintain the vehicle's driving force and resolve the ventilation stagnation state, until it is determined that the ventilation stagnation state is gone. Vehicle control system.

2. The vehicle control device according to claim 1, wherein the change in the operating conditions in the stall-resolving control is performed by adjusting the air-fuel ratio of the mixture burned in the supercharged engine.

3. The control device for a vehicle according to claim 1, wherein the supercharged engine is equipped with an exhaust recirculation device that recirculates a portion of the exhaust into the intake air, and the change in the operating conditions in the stagnation resolution control is performed by adjusting the amount of exhaust recirculation by the exhaust recirculation device.

4. The control device for a vehicle according to claim 1, wherein the supercharged engine is equipped with a variable valve timing mechanism that varies the valve timing of the intake valve, and the change in the operating conditions in the stagnation resolution control is performed by adjusting the valve timing.

5. The vehicle control device according to claim 1, wherein the change in the operating conditions in the stall-resolving control is performed by adjusting the gear ratio of the vehicle's transmission.

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