Vehicle control system

Abstract

This system allows for early detection of whether or not a foreign object has become lodged in the EGR valve. [Solution] The vehicle control device controls a vehicle that has an internal combustion engine and an EGR valve and performs idle stop when idle stop conditions are met. The vehicle control device comprises a drive command detection unit that detects a command value of the driving torque, a valve control unit that controls the EGR valve, an opening degree detection unit that detects the opening degree of the EGR valve, a jamming determination unit that determines whether or not a foreign object is jammed in the EGR valve based on the opening degree, and an idle stop control unit that permits or prohibits idle stop. The control device controls the EGR valve to close when the command value satisfies a first condition, determines whether or not a jamming condition exists when the command value satisfies a first condition, and permits or prohibits idle stop according to the jamming determination result when idle stop conditions are met, including the command value satisfying a second condition.

Description

Technical Field

[0001] The present invention relates to a vehicle control device for controlling a vehicle having an exhaust gas recirculation (EGR) valve.

Background Art

[0002] In recent years, in vehicles having an EGR valve, research and development have been conducted for the purpose of contributing to the development of a sustainable transportation system by ensuring the soundness of the EGR valve and improving the safety of the vehicle and traffic. As this type of technology, conventionally, a device has been known that determines whether or not the EGR valve is in a state where a foreign object has been bitten. For example, in the device described in Patent Document 1, when the target opening degree of the EGR valve set based on the target torque and rotational speed of the engine reaches a first predetermined opening degree or more and then reaches a second predetermined opening degree or less that is smaller than the first predetermined opening degree, it is determined whether or not the EGR valve has bitten a foreign object based on the difference between the detected intake pressure and the estimated intake pressure. If it is determined that a foreign object has been bitten, the automatic stop of the engine is prohibited.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in a configuration triggered by a change in the opening degree of the EGR valve as in the device described in Patent Document 1, it is difficult to determine at an early stage whether or not the EGR valve has bitten a foreign object.

Means for Solving the Problems

[0005] One aspect of the present invention is a vehicle control device for controlling a vehicle having an internal combustion engine and an EGR valve for adjusting the amount of exhaust gas recirculation from the internal combustion engine, and having an idle stop function that stops the idle operation of the internal combustion engine when predetermined idle stop conditions are met. The vehicle control device comprises a drive command detection unit for detecting a command value of the vehicle's driving torque, a valve control unit for controlling the EGR valve, an opening degree detection unit for detecting the opening degree of the EGR valve, a jamming determination unit for determining whether or not the EGR valve is jammed, based on the opening degree detected by the opening degree detection unit, and an idle stop control unit for permitting or prohibiting idle stop. The valve control unit controls the EGR valve to close when the command value detected by the drive command detection unit satisfies a first condition. The jamming determination unit determines whether or not the EGR valve is jammed when the command value detected by the drive command detection unit satisfies the first condition. The idle stop control unit permits or prohibits idle stop according to the determination result of the jamming determination unit when idle stop conditions are met, including the command value detected by the drive command detection unit satisfying a second condition. [Effects of the Invention]

[0006] According to the present invention, it is possible to quickly determine whether or not a foreign object has become lodged in the EGR valve. [Brief explanation of the drawing]

[0007] [Figure 1] A schematic diagram showing an example of the configuration around the engine of a vehicle to which a vehicle control device according to an embodiment of the present invention is applied. [Figure 2] Figure 1 shows a schematic diagram illustrating an example of the internal configuration of the EGR valve. [Figure 3] A time chart showing an example of EGR valve operation. [Figure 4] A schematic block diagram showing an example of the main components of a vehicle control device according to an embodiment of the present invention. [Figure 5] A flowchart showing an example of the decision process performed by the ECU in Figure 4. [Figure 6] A flowchart showing an example of a reset process performed by the ECU in Figure 4. [Modes for carrying out the invention]

[0008] Embodiments of the present invention will be described below with reference to Figures 1 to 6. Figure 1 is a schematic diagram showing an example of the configuration around the engine 1 of a vehicle V to which a vehicle control device according to an embodiment of the present invention is applied. The engine 1 is an internal combustion engine such as a gasoline engine or a diesel engine, and is equipped with an injector 1a that injects fuel into the combustion chamber or intake port of each cylinder. The fuel injection timing and fuel injection duration of the injector 1a are controlled by an electronic control unit (ECU) 10 (Figure 4) mounted on the vehicle V, thereby adjusting the amount of fuel (fuel injection amount) supplied to the engine 1. The fuel injection timing and fuel injection duration of the injector 1a are determined by predetermined characteristics according to the operating state of the engine 1, etc. The vehicle V may be equipped with only the engine 1 as a drive source, or it may be a hybrid vehicle equipped with the engine 1 and a drive motor. The engine 1 is also provided with a rotation speed sensor 1b that detects the engine speed.

[0009] As shown in Figure 1, the engine 1 is connected to an intake passage 3 via an intake manifold 2 and to an exhaust passage 5 via an exhaust manifold 4. Air drawn into the intake passage 3 via an air cleaner (not shown) has its flow rate adjusted by a throttle valve 6 provided in the intake passage 3 and is supplied to the engine 1 via the intake manifold 2. The intake passage 3 is also provided with an intake volume sensor 3a that detects the flow rate (intake volume) of air supplied to the engine 1.

[0010] The exhaust gas discharged from engine 1 through the exhaust manifold 4 into the exhaust passage 5 is purified by a catalytic converter 7 installed in the exhaust passage 5 and released into the atmosphere. A portion of the exhaust gas discharged into the exhaust passage 5 is recirculated to the intake passage 3 via the EGR passage 8. The flow rate of exhaust gas (EGR gas) recirculated from the exhaust passage 5 to the intake passage 3 via the EGR passage 8, i.e., the amount of exhaust gas recirculated from engine 1, is regulated by an EGR valve 9 installed in the EGR passage 8. The EGR valve 9 is equipped with a lift sensor 9a that detects the lift amount of the valve body (Figure 2) corresponding to the opening degree of the EGR valve 9. The EGR valve 9 is controlled by the ECU 10 (Figure 4).

[0011] Figure 2 is a schematic diagram showing an example of the internal configuration of the EGR valve 9, and shows the EGR valve 9 in a closed (fully closed) state. The EGR valve 9 is configured, for example, as an electrically operated poppet valve. As shown in Figure 2, the EGR valve 9 has a valve body 90 that constitutes part of the EGR passage 8. The valve body 90 has an inlet passage 91 connected to the EGR passage 8 on the exhaust passage 5 side and an outlet passage 92 connected to the EGR passage 8 on the intake passage 3 side. A substantially annular valve seat 93 centered on the vertical axis CL is provided in the valve body 90 between the inlet passage 91 and the outlet passage 92.

[0012] The EGR valve 9 further includes a valve body 94 seatable on a valve seat 93, a valve stem 95 integrally provided with the valve body 94, a compression spring 96 that biases the valve body 94 and valve stem 95 upward, and a solenoid (duty solenoid) 97 that drives the valve body 94 and valve stem 95 downward. Alternatively, a motor such as a stepping motor may be used to drive the valve body 94 and valve stem 95 instead of the solenoid. The compression spring 96 and solenoid 97 are housed in a housing 98 located above the valve body 90.

[0013] The through-hole 93a of the valve seat 93 has a frustoconical surface centered on the vertical axis CL and widens in diameter upwards. The valve body 94 is formed in a substantially frustoconical shape centered on the vertical axis CL and widens in diameter downwards. The valve stem 95 is provided so as to extend upward from the upper end of the valve body 94 along the vertical axis CL and is slidably supported along the vertical axis CL by a bearing 98a provided in the housing 98. A spring receiver 95a is formed on the valve stem 95, projecting horizontally in the outward diameter direction centered on the vertical axis CL.

[0014] The lower end of the compression spring 96 abuts against the upper end surface of the bearing 98a, and the upper end of the compression spring 96 abuts against the lower end surface of the spring receiver 95a. The compression spring 96 biases the valve body 94 and valve stem 95 upward via the spring receiver 95a. The solenoid 97 is connected to the spring receiver 95a and drives the valve body 94 and valve stem 95 downward via the spring receiver 95a.

[0015] As shown in Figure 2, when the solenoid 97 is off, the compression spring 96 biases the valve body 94 and valve stem 95 upward, causing the frustoconical surface of the valve body 94 to contact the lower end of the valve seat 93 (through hole 93a), thereby seating the valve body 94 on the valve seat 93 and closing the EGR valve 9. When the solenoid 97 is turned on, the valve stem 95 and valve body 94 are driven downward against the biasing force of the compression spring 96, causing the valve body 94 to separate from the valve seat 93, thereby opening the EGR valve 9.

[0016] The lift amount of the valve body 94, which corresponds to the opening degree of the EGR valve 9, i.e., the distance of the valve body 94 from the valve seat 93, is detected by a lift sensor 9a provided at the upper end of the valve stem 95. The lift amount of the EGR valve 9 when fully closed is 0 mm, and the lift amount when fully open is, for example, about 5 mm. The amount of current supplied to the solenoid 97 is controlled by the ECU 10 (Figure 4), thereby adjusting the lift amount of the EGR valve 9 (0 to 5 mm) and adjusting the flow rate of the EGR gas. The target lift amount Lc of the EGR valve 9 is determined by predetermined characteristics according to the operating state of the engine 1, and the EGR valve 9 (solenoid 97) is feedback controlled so that the lift amount La (thick solid line in Figure 3) detected by the lift sensor 9a becomes the target lift amount Lc (thick dashed line in Figure 3).

[0017] Vehicle V has an idle stop function that stops the engine 1 from idling by stopping fuel injection, in order to improve fuel efficiency. Idle stop is started when predetermined idle stop conditions are met. Idle stop conditions are met when the accelerator pedal is not operated, i.e., the accelerator opening decreases to 0%, such as when the vehicle is stopped, then operation of the brake pedal is detected, and the vehicle speed decreases to a predetermined vehicle speed (for example, about 10 km / h) or less. Hereinafter, the accelerator opening (0%) corresponding to the idle stop conditions will be referred to as the "idle stop threshold AP2". Idle stop ends when the brake pedal is not operated or the accelerator pedal is operated, such as when starting, and the idle stop conditions are no longer met. When idle stop ends, fuel injection is resumed and engine 1 is restarted.

[0018] FIG. 3 is a time chart showing an example of the operation of the EGR valve 9. The EGR (exhaust gas recirculation) of the engine 1 is permitted, for example, in a warm-up state where the engine water temperature detected by the engine water temperature sensor 11 reaches a predetermined water temperature. In the example of FIG. 3, after the engine 1 starts and enters the warm-up state and EGR is permitted, for the first time at time t1, the operation point of the engine 1 defined by the engine speed and the load (for example, the intake air amount) enters a predetermined EGR region, and the valve opening of the EGR valve 9 (target lift amount Lc>0) is commanded (EGR on). Thereafter, at time t2, when the operation point of the engine 1 enters a predetermined non-EGR region, the valve closing of the EGR valve 9 (target lift amount Lc = 0) is commanded (EGR off).

[0019] The EGR region is defined as a high-load region with a predetermined boundary intake air amount or more where no misfire occurs due to deterioration of the combustion state even when EGR gas is introduced into the combustion chamber, and the non-EGR region is defined as a low-load region with less than the boundary intake air amount. The boundary intake air amount is predetermined by a combustion test of the engine 1. The boundary intake air amount is, for example, the intake air amount corresponding to the accelerator opening (throttle opening) during constant-speed running of the vehicle V or during gentle deceleration where deceleration fuel cut is not performed. Hereinafter, the accelerator opening corresponding to the boundary intake air amount is referred to as "boundary threshold value AP1". The boundary threshold value AP1 of the accelerator opening is, for example, about 12%.

[0020] When the vehicle V running in the EGR on state stops, first, the driver eases the depression of the accelerator pedal so that the accelerator opening decreases to below the boundary threshold value AP1 (for example, 12%), and then when the driver removes the foot from the accelerator pedal, the accelerator opening decreases to below the idle stop threshold value AP2 (that is, 0%). Thereafter, when the driver switches to the brake pedal and depresses the brake pedal, the operation amount of the brake pedal detected by the brake sensor 14 reaches a predetermined value and the operation of the brake pedal is detected, and when the vehicle speed decreases to below a predetermined vehicle speed (for example, about 10 km / h), the idle stop condition is satisfied.

[0021] Therefore, it takes a certain amount of time (e.g., 2 seconds or more) from when the accelerator opening degree drops below the boundary threshold value AP1 until the idle stop condition is satisfied. Even when a single pedal that combines the functions of the accelerator pedal and the brake pedal is mounted on the vehicle V instead of the accelerator pedal and the brake pedal, it takes a similar amount of time. That is, the operation amount of the pedal changes from the operation amount corresponding to the boundary threshold value AP1 of the accelerator opening degree to the operation amount corresponding to the predetermined value of the operation amount of the brake pedal, is detected, and it takes a similar amount of time until the vehicle speed drops below the predetermined vehicle speed.

[0022] When the EGR is switched from on to off and the EGR valve 9 is closed from the open state, foreign matter may be caught in the EGR valve 9. For example, foreign matter flowing in from the inlet-side passage 91 in FIG. 2 and sandwiched between the valve seat 93 and the valve body 94 is caught between the lower end of the valve seat 93 (through hole 93a) and the conical surface of the valve body 94 when the valve body 94 moves upward (closing direction) in response to a closing command. Alternatively, foreign matter flowing in from the inlet-side passage 91 and passing between the valve seat 93 and the valve body 94 is caught between the lower end of the valve seat 93 (through hole 93a) and the conical surface of the valve body 94.

[0023] In the state where foreign matter is caught in the EGR valve 9, the valve body 94 seats on the valve seat 93 through the foreign matter, so that the lift amount becomes larger than the lift amount (0 mm) when contacting without the foreign matter. Such foreign matter caught between the valve seat 93 and the valve body 94 includes, for example, deposits that are combustion products (oxides and carbides) contained in the EGR gas deposited on the wall surface of the gas flow path such as the EGR passage 8 and have peeled off to become foreign matter.

[0024] When foreign matter is jammed in the EGR valve 9, it cannot be fully closed, causing EGR gas to flow into the combustion chamber. This prevents the proper air-fuel ratio from being maintained in the non-EGR region, making it difficult to maintain a stable combustion state of the engine 1 and to restart it. Foreign matter jammed in the EGR valve 9 can be dislodged downwards in the direction of gravity, i.e., toward the inlet passage 91 (Figure 2), by opening and closing the EGR valve 9 when the vehicle V is idle or stalled after the engine 1 has stopped running, or after the ignition is turned off.

[0025] However, depending on the duration of the idle stop, the EGR valve 9 may not be able to open and close sufficiently during the idle stop, and the jammed state may not be resolved, potentially leading to a failure to restart the engine 1. In other words, when foreign matter is jammed, the EGR valve 9 cannot be fully closed, so when restarting, EGR gas flows into the combustion chamber, making it impossible to secure an appropriate air-fuel ratio, and thus making restarting difficult. Therefore, in this embodiment, the vehicle control device is configured as follows to prevent engine 1 restart failure by early determination of whether or not foreign matter is jammed in the EGR valve 9, and by allowing or prohibiting the idle stop of the vehicle V according to the determination result.

[0026] Figure 4 is a schematic block diagram showing an example of the main components of a vehicle control device (hereinafter referred to as "device") 100 according to an embodiment of the present invention. As shown in Figure 4, the device 100 mainly comprises an ECU 10 that controls the injector 1a and the EGR valve 9, a group of sensors connected to the ECU 10, the injector 1a, and the EGR valve 9. The group of sensors includes a rotational speed sensor 1b, an intake air volume sensor 3a, a lift sensor 9a, a water temperature sensor 11 that detects engine water temperature, a vehicle speed sensor 12 that detects vehicle speed, an accelerator sensor 13 that detects the amount of accelerator pedal operation (accelerator opening), and a brake sensor 14 that detects the amount of brake pedal operation. Hereinafter, the accelerator sensor 13 that detects the accelerator opening, which is the command value of the driving torque of the vehicle V, may be referred to as the "drive command detection unit".

[0027] The ECU10 is composed of a computer including a processor such as a CPU, memory such as ROM and RAM, and other peripheral circuits. Functionally, the ECU10 has a valve control unit 15, a jamming detection unit 16, and an idle stop control unit 17, and functions as the valve control unit 15, the jamming detection unit 16, and the idle stop control unit 17.

[0028] The valve control unit 15 provides feedback control to the EGR valve 9 so that the lift amount La detected by the lift sensor 9a becomes a target lift amount Lc according to the current operating state of the engine 1. For example, when the EGR is on, if the accelerator opening decreases to below the boundary threshold AP1 and the intake amount detected by the intake amount sensor 3a decreases to below the boundary intake amount, causing the engine 1 to move from the EGR region to the non-EGR region, the EGR valve 9 is controlled to close (EGR off).

[0029] Furthermore, the valve control unit 15 controls the EGR valve 9 to perform a predetermined opening and closing operation when the engine 1 stops, provided that there has been one or more EGR on cycles after the ignition is turned on, i.e., after the first start in a single driving cycle, and that there is an EGR operation history. More specifically, the EGR valve 9 is controlled to perform a predetermined opening and closing operation when the vehicle V is idle stop and after the ignition is turned off, when the engine 1 has stopped running. The predetermined opening and closing operation may also be performed when the engine 1 stalls.

[0030] The valve control unit 15 commands the EGR valve 9 (solenoid 97) to perform a predetermined opening and closing operation, for example, by commanding the valve body 94 of the EGR valve 9 to reciprocate between the fully closed position and the fully open position a predetermined number of times (for example, about 3 times) to obtain a target lift amount. The predetermined opening and closing operation may vary depending on whether the engine is stopped with the ignition on (during idle stop or stall) or stopped after the ignition is turned off, and the number of opening and closing operations and the maximum opening degree (lift amount) during the operation may also vary.

[0031] By performing the opening and closing operation of the EGR valve 9 when the engine 1 is stopped, any foreign matter that may have become jammed when the EGR valve 9 is closed from the open state can be dislodged and removed, thereby ensuring that the engine 1 can be restarted. Furthermore, by performing the predetermined opening and closing operation, even minute foreign matter such as soot and rust adhering between the valve seat 93 (Figure 2) and the valve body 94 of the EGR valve 9 can be removed, thereby preventing a gap from forming between the valve seat 93 and the valve body 94 of the EGR valve 9 due to wear, which would cause EGR gas to flow into the combustion chamber when a full-close command is given. Performing such opening and closing operations during idle stop, which occurs relatively frequently, and removing foreign matter regularly can prevent the EGR valve 9 from sticking or becoming stiff due to the accumulation of soot and other substances.

[0032] The jamming detection unit 16, provided there is an EGR operation history, determines whether or not a foreign object is jammed in the EGR valve 9 when the accelerator opening detected by the accelerator sensor 13 falls below the boundary threshold AP1 and a command is issued to fully close the EGR valve 9. More specifically, it compares the lift amount La detected by the lift sensor 9a with a predetermined threshold α, and determines that a jamming state exists if it is greater than or equal to threshold α, and determines that there is no jamming state if it is less than threshold α. Restarting the engine 1 from a non-combustion state where operation has stopped becomes difficult even if only a small amount of EGR gas flows into the combustion chamber. The threshold α is predetermined as the lift amount (for example, about 0.1 to 0.3 mm) that would lead to a failed restart or stall of the engine 1.

[0033] The jamming detection unit 16 starts its determination after waiting for a predetermined response waiting time T. The response waiting time T is the time required for feedback control of the EGR valve 9 (for example, about 130 milliseconds), and is set considering the time required for the actual lift amount La to follow the target lift amount Lc (for example, about 60 milliseconds), the time required for the lift amount La after following to be detected by the lift sensor 9a (for example, about 20 milliseconds), and an appropriate buffer time. By waiting for the response waiting time T, the jamming detection unit 16 can perform its determination with high accuracy.

[0034] Since the determination by the jamming detection unit 16 is completed in a few milliseconds, the determination by the jamming detection unit 16 is completed after the accelerator opening has decreased to or below the boundary threshold AP1 and a response waiting time T (for example, about 130 milliseconds) has elapsed. Since it takes a certain amount of time (for example, 2 seconds or more) from when the accelerator opening has decreased to or below the boundary threshold AP1 until the idle stop condition is met, the determination by the jamming detection unit 16 is completed before the idle stop condition is met.

[0035] The idle stop control unit 17 determines whether the idle stop conditions (vehicle speed below a predetermined speed, accelerator pedal not operated, and brake pedal operated) have been met based on the detection results of the vehicle speed sensor 12, accelerator sensor 13, and brake sensor 14. More specifically, it determines whether the accelerator opening has decreased to below the idle stop threshold AP2 (0%), whether the brake pedal has been operated, and whether the vehicle speed has decreased to below a predetermined speed (for example, around 10 km / h). If it is determined that the idle stop conditions have been met, the injector 1a is controlled to stop fuel injection, provided that idle stop is permitted, and idle stop is performed.

[0036] The idle stop control unit 17 further permits or prohibits idle stop when the idle stop condition is met, according to the determination result of the jamming determination unit 16. More specifically, if the jamming determination unit 16 determines that there is no jamming, idle stop is permitted, and if the jamming determination unit 16 determines that there is a jamming, idle stop is prohibited. Since the determination by the jamming determination unit 16 is usually completed by the time the idle stop condition is met, when the idle stop condition is met, idle stop can be appropriately permitted or prohibited immediately according to the determination result of the jamming determination unit 16.

[0037] Even if the idle stop control unit 17 determines that the idle stop conditions have been met, it will prohibit idle stop until the jamming determination unit 16 determines that there is no jamming condition. More specifically, when there is an EGR operation history and the EGR valve 9 is commanded to be fully closed, the jamming determination unit 16 begins its determination, idle stop is prohibited, and the idle stop is prohibited until it is determined that there is no jamming condition. If idle stop is prohibited and idle stop is not performed despite the idle stop conditions being met (i.e., idle operation continues), the driver may be notified via the vehicle V's multi-information display (MID) or the like.

[0038] The state in which idle stop is prohibited is released when the jamming detection unit 16 determines that there is no jamming. If the idle stop conditions are met when idle stop is permitted, the injector 1a is controlled to stop fuel injection, and idle stop is initiated. In this case, idle stop may be initiated while the vehicle V is stationary. The state in which idle stop is prohibited is also released when EGR is commanded to turn on (target lift amount Lc>0) from the state of EGR off (target lift amount Lc=0).

[0039] In this way, when a foreign object gets stuck in the EGR valve 9, the idle stop function of the vehicle V is prohibited, and the idle operation of the engine 1 is continued, thereby reliably preventing the engine 1 from failing to restart due to the inflow of EGR gas into the combustion chamber. Furthermore, by prohibiting the idle stop function for a response waiting time T after the EGR is commanded to turn off from the EGR ON state, until the jamming detection unit 16 determines that there is no jamming, it is possible to prevent the engine from stopping due to a false detection. This further reliably prevents the engine 1 from failing to restart due to the inflow of EGR gas into the combustion chamber.

[0040] Figures 5 and 6 are flowcharts showing examples of the determination process and reset process performed by the ECU 10, respectively. The processes shown in these flowcharts start when the ECU 10 is activated and are repeated at predetermined intervals (for example, every few seconds).

[0041] As shown in Figure 5, the determination process first determines in step S1 whether or not there is an EGR operation history. If the result in step S1 is positive, the process proceeds to step S2; if the result in step S1 is negative, the process ends. In step S2, it is determined whether or not the accelerator opening has decreased to or below the boundary threshold AP1 (for example, 12%), that is, whether or not a command has been issued to turn off EGR (target lift amount Lc=0) from the state of EGR on (target lift amount Lc>0).

[0042] If the result in step S2 is positive, the process proceeds to step S3; if the result in step S2 is negative, the process ends. In step S3, the count for the response waiting time T (response waiting timer) is started, and idle stop is prohibited. Next, in step S4, it is determined whether or not the response waiting time T has elapsed. If the result in step S4 is positive, the process proceeds to step S5; if the result in step S4 is negative, the process returns to step S2.

[0043] In step S5, it is determined whether the lift amount La detected by the lift sensor 9a is greater than or equal to the threshold α. If the result in step S5 is positive, the process proceeds to step S6 to determine that a jamming condition exists. If the result in step S5 is negative, the process proceeds to step S7 to determine that a jamming condition does not exist.

[0044] Next, in step S8, it is determined whether or not the idle stop condition has been met. If it is affirmed in step S8, the process proceeds to step S9; if it is denied in step S8, the current process ends. In step S9, idle stop is permitted or prohibited depending on the determination results in steps S5 to S7. That is, if it is determined in step S6 that there is a jammed state, idle stop is prohibited (maintaining the state in which idle stop was prohibited in step S3), and if it is determined in step S7 that there is no jammed state, idle stop is permitted (releasing the state in which idle stop was prohibited in step S3).

[0045] As shown in Figure 6, in the reset process, first in step S10, it is determined whether or not a command has been issued to turn EGR on (target lift amount Lc>0) from the state of EGR off (target lift amount Lc=0). If the result in step S10 is positive, the process proceeds to step S11; if the result in step S10 is negative, the process ends. In step S11, the response waiting timer and the result of the determination of whether or not there is a jammed state are reset, and the state in which idle stop is prohibited is released (reset).

[0046] As shown in Figure 3, when a vehicle V that is running with the EGR on comes to a stop, the accelerator opening decreases to below the boundary threshold AP1 (e.g., 12%), the intake air volume decreases to below the boundary intake air volume, and at time t2, a command is issued to turn the EGR off (Lc=0) from the state of EGR on (Lc>0). At this time, the response waiting time T count begins, and idle stop is prohibited (steps S1~S3 in Figure 5). Subsequently, at time t3, when the response waiting time T has elapsed, it is determined whether or not there is a jamming condition based on the lift amount La detected by the lift sensor 9a (S4~S7). Further on, when the accelerator opening decreases to below the idle stop threshold AP2 (i.e., 0%), brake pedal operation is detected, and at time t4 the vehicle speed decreases to below a predetermined vehicle speed (e.g., about 10 km / h), and the idle stop condition is met, idle stop is permitted or prohibited (S8~S9).

[0047] If vehicle V stops at time t4 and is determined to be in a jammed state (La≧α) when the idle stop condition is met based on the detection results of sensor groups 12-14, idle stop is prohibited (the prohibited state is maintained), and engine 1 continues to operate without transitioning to idle stop, transitioning to idle operation. If vehicle V starts at time t5 and the idle stop condition is no longer met based on the detection results of sensor groups 12-14, the idle operation state ends. By prohibiting idle stop for vehicle V in a jammed state and continuing idle operation of engine 1, it is possible to reliably prevent engine 1 from failing to restart due to EGR gas inflow into the combustion chamber and to reliably restart the vehicle.

[0048] When the EGR is turned on (Lc>0) at time t6 from the EGR off (Lc=0) state, the response waiting time T, the determination result of whether or not there is a jammed state, and the state in which idle stop is prohibited are reset (steps S10~S11 in Figure 6). When the EGR is restarted and the EGR valve 9 opens, the foreign object that was jammed in the EGR valve 9 falls out and passes through the outlet passage 92 along with the EGR gas.

[0049] At time t7, the accelerator opening decreases to below the boundary threshold AP1, and the intake air volume decreases to below the boundary intake air volume. When the EGR is turned off (Lc=0) from the EGR on state (Lc>0), the response waiting time T countdown begins, and idle stop is prohibited (steps S1-S3 in Figure 5). Subsequently, at time t8, when the response waiting time T has elapsed, it is determined whether or not there is a jamming condition based on the lift amount La detected by the lift sensor 9a (S4-S7). If it is determined that there is no jamming condition when the idle stop condition is met (La<α), idle stop is permitted (the prohibited state is released), and by performing idle stop, unnecessary fuel consumption can be suppressed and the fuel efficiency of the vehicle V can be improved. In addition, during idle stop, the EGR valve 9 is opened and closed, and minute foreign matter is removed.

[0050] When the vehicle V is turned off, the EGR valve 9 opens and closes at time t9, removing minute foreign objects. By opening and closing the EGR valve 9 during idle stop when the engine 1 is stopped or after the ignition is turned off, minute foreign objects are removed, which reliably prevents EGR gas from flowing into the combustion chamber during subsequent starting (restarting), thus reliably preventing restart failures. In particular, after the ignition is turned off, when there is little likelihood of a restart being required immediately afterward, opening and closing the EGR valve 9 regardless of whether or not it is jammed can remove foreign objects that have become jammed in the EGR valve 9 while preventing restart failures.

[0051] According to embodiments of the present invention, the following effects can be achieved. (1) The device 100 controls a vehicle V which has an engine 1 and an EGR valve 9 that adjusts the amount of exhaust gas recirculation from the engine 1, and an idle stop function that stops the idle operation of the engine 1 when predetermined idle stop conditions are met (Figure 1). The device 100 includes a drive command detection unit (accelerator sensor 13) that detects the accelerator opening, which is the command value of the driving torque of the vehicle V, a valve control unit 15 that controls the EGR valve 9, a lift sensor 9a that detects a lift amount La corresponding to the opening of the EGR valve 9, a jamming determination unit 16 that determines whether or not the EGR valve 9 is jammed, which is a state in which foreign matter is jammed, based on the lift amount La detected by the lift sensor 9a, and an idle stop control unit 17 that permits or prohibits idle stop (Figure 4).

[0052] The valve control unit 15 controls the EGR valve 9 to close when the accelerator opening detected by the accelerator sensor 13 falls below the boundary threshold AP1 (times t2, t7 in Figure 3). The jamming determination unit 16 determines whether or not there is a jamming condition when the accelerator opening detected by the accelerator sensor 13 falls below the boundary threshold AP1 (times t2, t7 in Figure 3, steps S2-S7 in Figure 5). The idle stop control unit 17 permits or prohibits idle stop according to the determination result of the jamming determination unit 16 when the idle stop condition is met, including the accelerator opening detected by the accelerator sensor 13 falling below the idle stop threshold AP2 (time t4 in Figure 3, steps S8-S9 in Figure 5).

[0053] In other words, the jamming detection unit 16 does not determine jamming based on driving conditions such as vehicle speed or values ​​that change according to driving conditions such as the target lift amount Lc of the EGR valve 9, but rather based on changes in the accelerator opening, which is the command value of the driving torque that is the starting point for changing the driving conditions of the vehicle V. Therefore, it is possible to determine early whether or not a foreign object has become jammed in the EGR valve 9. Furthermore, in the case of jamming, idle stop of the vehicle V is prohibited and idle operation of the engine 1 is continued, thereby reliably preventing the engine 1 from failing to restart due to the inflow of EGR gas into the combustion chamber.

[0054] (2) The idle stop threshold AP2 (0%) for accelerator opening is smaller than the boundary threshold AP1 (for example, around 12%). By setting the boundary threshold AP1, which is used for jamming detection, to be larger than the idle stop threshold AP2, which is used to permit or prohibit idle stop, the jamming detection can be completed before permitting or prohibiting idle stop. In this case, when the idle stop condition is met, idle stop can be appropriately permitted or prohibited immediately according to the jamming detection result.

[0055] (3) The device 100 further includes a brake sensor 14 for detecting the amount of operation of the brake pedal of the vehicle V and a vehicle speed sensor 12 for detecting the vehicle speed of the vehicle V (Figure 4). The idle stop condition further includes the brake pedal being operated after the accelerator opening has decreased to or below the idle stop threshold AP2, and the vehicle speed decreasing to or below a predetermined speed. The jamming determination is completed within a few milliseconds after the accelerator opening has decreased to or below the boundary threshold AP1, while it takes a certain amount of time (e.g., 2 seconds or more) for the idle stop condition to be met, so the jamming determination can be completed before the idle stop condition is met.

[0056] (4) The EGR valve 9 has a valve seat 93 and a valve body 94 that is seatable on the valve seat 93 (Figure 2). The opening degree detection unit is a lift sensor 9a that detects the amount of separation of the valve body 94 from the valve seat 93 (lift amount La) as the opening degree (Figures 2 and 4). When a jamming determination is made based on the lift amount La, which is the opening degree of the EGR valve 9, a jamming determination can be made earlier and with greater accuracy than when a physical quantity that changes after the opening degree of the EGR valve 9 has changed (for example, intake pressure).

[0057] (5) The valve control unit 15 controls the EGR valve 9 to open and close after the vehicle V is turned off (time t9 in Figure 3). In this way, by opening and closing the EGR valve 9 after the ignition is turned off, when there is little possibility of a restart being required immediately afterward, regardless of whether or not there is a jammed state, it is possible to remove foreign matter that has become jammed in the EGR valve 9 while preventing restart failure.

[0058] (6) If the idle stop control unit 16 determines that there is a jamming condition, the idle stop control unit 17 prohibits idle stop, and if the jamming determination unit 16 determines that there is no jamming condition, idle stop is permitted (steps S5 to S7 in Figure 5). The valve control unit 15 controls the EGR valve 9 to open and close when idle stop is performed. In this way, idle stop is permitted when there is no jamming condition, and idle stop is performed when the idle stop conditions are met, thereby suppressing unnecessary fuel consumption and improving the fuel efficiency of the vehicle V. In addition, by performing the opening and closing operation of the EGR valve 9 during idle stop, which occurs relatively frequently, even minute foreign objects can be reliably removed.

[0059] (7) Even if the idle stop condition is met, the idle stop control unit 17 will prohibit idle stop until the jamming determination unit 16 determines that there is no jamming (step S3 in Figure 5). In other words, by prohibiting idle stop for a response waiting time T after the EGR is commanded to turn off from the EGR ON state, it is possible to prevent engine stopping due to misjudgment and to more reliably prevent restart failure due to EGR gas flow into the combustion chamber.

[0060] The above embodiment can be modified into various forms. Modifications will be described below. In the above embodiment, an example was shown in Figure 1, etc., in which exhaust gas after passing through the catalytic converter 7 is recirculated as EGR gas. However, the vehicle only needs to have an internal combustion engine and an EGR valve for adjusting the amount of exhaust gas recirculation from the internal combustion engine, and the arrangement of the parts of the internal combustion engine is not limited to those exemplified. For example, exhaust gas before passing through the catalytic converter 7 may be recirculated as EGR gas. The EGR passage 8 may be directly connected to the exhaust manifold 4 instead of the exhaust passage 5, or directly connected to the intake manifold 2 instead of the intake passage 3, or connected to the intake manifold 2 via an appropriate chamber or the like for mixing EGR gas with fresh air.

[0061] In the above embodiment, the specific internal configuration of the EGR valve 9 was illustrated and explained using Figure 2, etc., but the EGR valve is not limited to the illustrated configuration. For example, it may be a valve other than a poppet valve, such as a butterfly valve. That is, foreign matter can get caught in butterfly valves as well as in poppet valves, and the same foreign matter can be removed by opening and closing the valve. When using a butterfly valve, the valve opening degree can be detected by an angle sensor instead of a lift sensor.

[0062] In the above embodiment, an example was described in which the accelerator opening is detected by the accelerator sensor 13 as the command value for the driving torque of the vehicle V. However, the command value for the driving torque of the vehicle is not limited to this. For example, it may be the requested torque for the engine according to the accelerator opening during hybrid driving of a hybrid vehicle. Alternatively, it may be the requested torque for the engine according to the driving plan during autonomous driving of an autonomous vehicle.

[0063] The above description is merely an example, and the present invention is not limited by the embodiments and modifications described above, as long as the features of the present invention are not impaired. It is also possible to arbitrarily combine one or more of the above embodiments and modifications, and to combine modifications with each other. [Explanation of Symbols]

[0064] 1 Engine, 1a Injector, 1b Rotation speed sensor, 2 Intake manifold, 3 Intake passage, 3a Intake volume sensor, 4 Exhaust manifold, 5 Exhaust passage, 6 Throttle valve, 7 Catalytic converter, 8 EGR passage, 9 EGR valve, 9a Lift sensor, 10 ECU (Electronic Control Unit), 11 Water temperature sensor, 12 Vehicle speed sensor, 13 Accelerator sensor, 14 Brake sensor, 15 Valve control unit, 16 Seizing detection unit, 17 Idle stop control unit, 90 Valve body, 91 Inlet passage, 92 Outlet passage, 93 Valve seat, 93a Through hole, 94 Valve element, 95 Valve shaft, 95a Spring support, 96 Compression spring, 97 Solenoid, 98 Housing, 98a Bearing, 100 Vehicle control device, V Vehicle

Claims

1. A vehicle control device for controlling a vehicle having an internal combustion engine and an EGR valve for adjusting the amount of exhaust gas recirculation from the internal combustion engine, and having an idle stop function that stops the idle operation of the internal combustion engine when predetermined idle stop conditions are met, A drive command detection unit that detects the command value of the vehicle's driving torque, A valve control unit that controls the EGR valve, An opening degree detection unit for detecting the opening degree of the EGR valve, Based on the opening degree detected by the opening degree detection unit, a jamming determination unit determines whether or not the EGR valve is in a jammed state, where a foreign object is jammed in it. The system includes an idle stop control unit that permits or prohibits the idle stop, The valve control unit controls the EGR valve to close when the command value detected by the drive command detection unit satisfies the first condition. The jamming determination unit determines whether or not the jamming state is present when the command value detected by the drive command detection unit satisfies the first condition. The vehicle control device is characterized in that, when the idle stop control unit satisfies the idle stop condition, which includes the command value detected by the drive command detection unit satisfying the second condition, the idle stop control unit permits or prohibits the idle stop according to the determination result of the jamming determination unit.

2. In the vehicle control device according to claim 1, The drive command detection unit includes an accelerator operation amount detection unit that detects the amount of operation of the vehicle's accelerator pedal, The first condition includes the amount of operation of the accelerator pedal decreasing to or below a first threshold, The vehicle control device is characterized in that the second condition includes the amount of operation of the accelerator pedal decreasing to a second threshold that is smaller than the first threshold.

3. In the vehicle control device according to claim 2, The system further includes a brake operation amount detection unit for detecting the amount of operation of the brake pedal of the vehicle and a vehicle speed detection unit for detecting the driving speed of the vehicle. The aforementioned idle stop conditions are: After the amount of operation of the accelerator pedal decreases to or below the second threshold, A vehicle control device characterized by the operation of the brake pedal and the reduction of the driving speed to a predetermined speed or less.

4. In the vehicle control device according to any one of claims 1 to 3, The EGR valve comprises a valve seat and a valve body that is seatable on the valve seat. The vehicle control device is characterized in that the opening degree detection unit is a lift sensor that detects the distance between the valve body and the valve seat as the opening degree.

5. In the vehicle control device according to any one of claims 1 to 3, The vehicle control device is characterized in that the valve control unit controls the EGR valve to perform an opening and closing operation after the vehicle's ignition is turned off.

6. In the vehicle control device according to any one of claims 1 to 3, The idle stop control unit, when the jamming determination unit determines that a jamming condition exists, prohibits the idle stop, and when the jamming determination unit determines that a jamming condition does not exist, permits the idle stop. The vehicle control device is characterized in that the valve control unit controls the EGR valve to open and close when the idle stop is performed.

7. In the vehicle control device according to any one of claims 1 to 3, The vehicle control device is characterized in that the idle stop control unit prohibits the idle stop even if the idle stop condition is met, until the jamming determination unit determines that there is no jamming condition.

8. In the vehicle control device according to claim 7, The vehicle control device is characterized in that the idle stop control unit prohibits the idle stop when the jamming determination unit determines that the jamming condition is present, and permits the idle stop when the jamming determination unit determines that the jamming condition is not present.

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