Vehicle control devices

Abstract

To enhance fuel economy through improving idling stop continuity.SOLUTION: A vehicle control device executes automatic stop control of an engine 3 when a predetermined engine stop condition is met, and automatic start-up control of the engine 3 when a predetermined engine restart condition is met while idling stop control is in execution. In the vehicle control device, drive control of a pump 13a is executed when a normal drive condition, in which negative pressure of a brake booster 14 is reduced by a predetermined amount, is met. However, an integrated control ECU 11 executes the drive control of the pump 13a even when the normal drive condition is not met if a special drive condition is met before the idling stop control is executed. Thus, driving the pump 13a while the subsequent idling stop control is in execution can prevent consumption current related to the restart condition of the engine 3 from exceeding a threshold.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a vehicle control device including control means for stopping an operating engine when a predetermined engine automatic stop condition is satisfied and automatically restarting a stopped engine when a predetermined engine restart condition is satisfied.

Background Art

[0002] Conventionally, a vehicle has been proposed that automatically stops the engine idling when a predetermined idling stop start condition is satisfied (see, for example, Patent Document 1). Here, as the predetermined idling stop start conditions, it is exemplified that all conditions such as (i) the vehicle is stopped, (ii) the battery capacity is a predetermined amount or more, (iii) the temperature of the engine cooling water is a predetermined value or more, and (iv) the difference between the set temperature of the air conditioner and the temperature inside the vehicle compartment is a predetermined value or less are satisfied.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in a vehicle, a brake booster for assisting the operating force of the brake pedal is installed. However, since the brake booster uses engine negative pressure, there is a possibility that the engine negative pressure decreases and the desired braking force cannot be obtained when the engine is stopped or at low engine speeds. Therefore, when the engine negative pressure decreases, there is an electric negative pressure pump system (EVP system) that supplies negative pressure to the brake booster with an electric pump to compensate for the decrease.

[0005] In vehicles equipped with an electric vacuum pump system for idle stop systems, if the vacuum pressure in the brake booster falls below a threshold while the engine is idled, the electric vacuum pump is activated to raise the vacuum pressure in the brake booster. In addition, in idle stop vehicles, the engine automatically restarts when certain conditions for engine restart are met during idle stop. In some cases, one of these conditions is that the vehicle's current consumption exceeds a threshold. In this case, if the electric vacuum pump is activated during idle stop, the current consumption will exceed the threshold, causing the idle stop system to be deactivated and reducing the efficiency of fuel efficiency improvement.

[0006] This invention was made in view of the above-mentioned problems, and aims to improve fuel efficiency by improving the continuity of idle stop. [Means for solving the problem]

[0007] To achieve the above-mentioned objectives, the vehicle control device of the present invention includes a brake pedal of In a vehicle control device that automatically stops the running engine when the vehicle decelerates to a predetermined speed by pressing the accelerator and a predetermined automatic engine stop condition is met, and automatically restarts the stopped engine when a predetermined engine restart condition is met, the device comprises a brake assist means that assists the brake using engine negative pressure, and a negative pressure assist means that supplies auxiliary negative pressure to the brake assist means by controlling the drive of a pump, and the predetermined engine restart condition is the vehicle's current consumption including the current required to drive the pump. The threshold value for the aforementioned engine restart conditions Including exceeding the negative pressure of the brake assist means, the negative pressure of the brake assist means , a pressure value higher on the atmospheric pressure side than the limit negative pressure that can be reached by driving the pump, and higher than a pre-set drive stop threshold. If normal operating conditions are met 、 The pump is driven to supply the auxiliary negative pressure, and it can be estimated that the predetermined automatic engine stop condition is met while the vehicle is decelerating and before the normal driving condition is met. In that case, The first special driving condition was met. asBy driving the pump and supplying the auxiliary negative pressure, the negative pressure of the brake assist means is increased before the predetermined automatic engine stop condition is met, and the current consumption is reduced by the drive control of the pump after the predetermined automatic engine stop condition is met. Conditions for restarting the engine The feature is that it prevents the threshold from being exceeded (Claim 1).

[0008] Furthermore, the negative pressure assisting means is used during vehicle deceleration. can be Before the above normal driving conditions are met and during standby for engine shutdown based on the fulfillment of the predetermined automatic engine shutdown conditions, 2 Special driving conditions The condition that it can be presumed that pumping brakes was performed. When the condition is met, the pump is driven to supply the auxiliary negative pressure, thereby increasing the negative pressure of the brake assist means before the predetermined automatic engine stop condition is met, and the current consumption is controlled by the drive control of the pump after the predetermined automatic engine stop condition is met. Conditions for restarting the engine The threshold may be kept from being exceeded (Claim 2).

[0009] Furthermore, the pump may be an electric negative pressure pump (Claim 3). [Effects of the Invention]

[0010] According to the invention of claim 1, when the vehicle is decelerating, the negative pressure of the brake assist means It is higher than the drive stop threshold. It can be estimated that predetermined automatic engine stop conditions are met before normal driving conditions are met. In that case, The first special driving condition was met. as Because the pump is driven and auxiliary negative pressure is supplied to the brake assist mechanism, the normal driving conditions are less likely to be met and the pump less likely to be driven during automatic engine stop (idle stop). In this case, the threshold current consumption required for engine restart conditions is less likely to be exceeded during automatic engine stop, improving the continuity of idle stop and consequently improving the vehicle's fuel efficiency.

[0011] According to the invention of claim 2, The vehicle is decelerating, before the normal driving conditions are met, and while the engine is in standby mode for stopping based on the meeting of the predetermined automatic engine stop conditions, the second special driving condition is met. It can be inferred that pumping the brakes was performed. The conditionsEven when this holds, the negative pressure of the brake assist means can be increased in advance before the idling stop, improving the continuity of the idling stop and also improving the fuel efficiency of the vehicle.

[0012] According to the invention of claim 3, by using an electric negative pressure pump that consumes current when driving the pump, the significance of increasing the negative pressure of the brake assist means in advance before the idling stop and making it difficult to drive the pump of the negative pressure assist means is improved.

Brief Description of the Drawings

[0013] [Figure 1] It is a block diagram of an embodiment of the vehicle control device of the present invention. [Figure 2] It is a diagram comparing the timing charts of each parameter when the brake is depressed again during the idling stop after stopping with the conventional timing chart. [Figure 3] It is a diagram comparing the timing charts of each parameter when the brake is depressed again during the idling stop while driving with the conventional timing chart. [Figure 4] It is a diagram comparing the timing charts of each parameter when the idling stop is implemented after stopping with a pumping brake with the conventional timing chart. [Figure 5] It is a diagram comparing the timing charts of each parameter when the idling stop is implemented while driving with a pumping brake with the conventional timing chart.

Embodiments for Carrying Out the Invention

[0014] Next, in order to explain the present invention in more detail, an embodiment when the present invention is applied to an idling stop vehicle will be described in detail with reference to FIGS. 1 to 5.

[0015] FIG. 1 shows a block configuration of a vehicle control device provided in an idling stop vehicle 1 (sometimes referred to as vehicle 1). The idling stop vehicle 1 is equipped with a relatively small-capacity 12V lead battery 2 as a power source in order to achieve weight reduction, miniaturization, etc. The negative terminal of this battery 2 is connected to the vehicle body of the idling stop vehicle 1.

[0016] In FIG. 1, 3 is the engine of the idling stop vehicle 1, 4 is a CVT on the transmission side of the engine 3, and a torque converter (including a lock-up clutch mechanism) 5 is interposed between the engine 3.

[0017] 6 is a starter for starting the engine 3, which is supplied with power from the battery 2 via a relay 7. 9 is a generator with a motor function (hereinafter referred to as ISG (Integrated Starter Generator)) to which the rotational force of the engine 3 is transmitted via a belt 10. During running, it charges the battery 2 with power generation output, and operates as a motor under predetermined conditions to generate the running driving force of the idling stop vehicle 1.

[0018] The relay 7 has a relay coil 7a and a relay switch 7b. When current flows through the relay coil 7a, the relay switch 7b becomes ON, the starter 6 is supplied with power from the battery 2, and the engine 3 starts. Also, when the energization of the relay coil 7a stops, the relay switch 7b becomes OFF, and the power supply to the starter 6 is stopped.

[0019] 11 is an integrated control ECU that combines an EFI control unit that calculates the required torque based on the accelerator opening detected by the accelerator sensor (not shown) and controls the fuel injection amount, intake air amount, ignition timing, etc. of the engine 3 to output this required torque; an idle stop control unit that controls idle stop control; a CVT control unit that controls CVT control; an ABS / VSC control unit that prevents skidding and spinning; and an EVP control unit that controls the drive of the vacuum pump 13a of the EVP unit 13. In addition, there are other units not shown, such as an engine ECU that controls the engine and an ISGECU that controls the ISG. Each ECU is formed by a microcomputer, etc., and exchanges information via a communication bus such as CAN (not shown).

[0020] The integrated control ECU 11 includes a first driver IC 11a connected to one end of the relay coil 7a and functioning as a switch to determine whether or not to connect that end to the battery 2, a second driver IC 11b connected to the other end of the relay coil 7a and functioning as a switch to determine whether or not to ground that other end, and a CPU 11c that controls these ICs 11a and 11b and other functions. The ECU performs controls such as restarting the engine 3 after idling stop (described later) and driving the pump 13a of the EVP unit 13 to supply auxiliary negative pressure to the brake booster 14.

[0021] The brake booster 14 assists the operating force of the brake pedal 19 and consists of a constant pressure chamber (not shown) that stores engine negative pressure generated by the operation of the engine 3, and a variable pressure chamber (not shown) that stores air at a higher pressure than the engine negative pressure. The brake booster 14 is connected to a master cylinder 15 which is connected to the reservoir tank of the brake system. Brake fluid (brake oil) is stored in the reservoir tank. A negative pressure sensor 20 is also provided in the constant pressure chamber of the brake booster 14 and detects the pressure in the constant pressure chamber as the booster negative pressure. The detection signal from the negative pressure sensor 20 is output to the integrated control ECU 11. The pump 13a of the EVP unit 13 is connected to the constant pressure chamber of the brake booster 14.

[0022] The EVP unit 13 supplies negative pressure to compensate when the negative pressure value in the constant pressure chamber of the brake booster 14 decreases, and includes a pump 13a. The pump 13a is, for example, an electric negative pressure pump, which, when driven, draws gas from the constant pressure chamber of the brake booster 14, thereby creating a negative pressure in the constant pressure chamber that is lower than atmospheric pressure (supplying negative pressure). In this embodiment, the EVP unit 13 and the integrated control ECU 11 are electrically connected, and the drive of the pump 13a is controlled by the CPU 11c of the integrated control ECU 11.

[0023] (Idling stop control) Here, we will explain the general control and operation of the idle stop vehicle 1. When the driver starts the engine 3, if the ignition (IG) key switch 17 is turned ON (engine start command) while the shift lever (not shown) is in the P or N position, the signal from the IG key switch 17 is input to the CPU 11c of the integrated control ECU 11. Based on this input, the CPU 11c instantly energizes the relay 7 and turns it ON. This supplies power from the battery 2 to the starter 6, starting the starter 6 and starting the stopped engine 3 (initial start).

[0024] Once engine 3 starts and battery 2 is fully charged by the ISG's generated power, the CPU 11c of the integrated control ECU 11 performs idle stop control until engine 3 stops when the IG key switch 17 is turned off.

[0025] The CPU 11c of the integrated control ECU 11 receives input such as vehicle speed information from the vehicle speed sensor 8, shift position information from the shift range switch 16, and negative pressure information from the negative pressure sensor 20. It also receives information about the engine 3, such as engine speed and coolant temperature, as well as information about the battery 2, such as current and temperature, master cylinder pressure, lock-up clutch information, and information about various switches inside the vehicle, such as the stop lamp switch and courtesy light switch, via the communication bus.

[0026] Based on this information, the CPU 11c of the integrated control ECU 11 during idle stop control commands the engine ECU to stop the engine when predetermined engine stop conditions are met, and the engine ECU automatically stops the engine 3 by restricting the fuel throttle, etc. Here, predetermined engine stop conditions are, for example, when the driver presses the brake pedal 19 in accordance with a red traffic light, etc., and the master cylinder pressure is above a predetermined pressing pressure (the amount the brake pedal is pressed is above a predetermined value), and for example, the stop lamp is lit and the vehicle 1 has decelerated to a predetermined speed (for example, 9 km / h or less).

[0027] Whether the master cylinder pressure is above a predetermined depression pressure can be determined, for example, based on the detection value of a brake pedal position sensor (not shown) that detects the position of the brake pedal. Furthermore, whether the vehicle 1 has decelerated to a predetermined speed can be determined, for example, based on the output value from the vehicle speed sensor 8.

[0028] Next, if the predetermined engine restart conditions are met during idle stop, the CPU 11c of the integrated control ECU 11 momentarily energizes the relay 7 to turn it on, supplies power from the battery 2 to the starter 6 to start the starter 6, and automatically restarts the stopped engine 3. The specified engine restart conditions are, for example, (i) When the driver releases the brake pedal 19 and the amount of pressure applied to the brake pedal 19 falls below a predetermined threshold (ii) When the shift position information from the shift range switch 16 changes from "D range" or "N range" to "P range (parking range)" (iii) When the shift position information from the shift range switch 16 changes to "R range (reverse range)" (iv) When the accelerator pedal is pressed (when the amount of pressure on the accelerator pedal is greater than or equal to a predetermined value) (v) When the current consumption is greater than or equal to a predetermined value (vi) When the air conditioner is in use and the difference between the set temperature and the temperature inside the car becomes large. (vii) When the defroster switch is turned ON (viii) When the driver unbuckles their seatbelt (ix) When steering input is detected If any of (i) to (ix) is true, the CPU 11c of the integrated control ECU 11 performs automatic start control (engine restart control) of the engine 3.

[0029] (Negative pressure assistance by an electric vacuum pump) (Normal assistance) The CPU 11c of the integrated control ECU 11 normally controls the operation of the pump 13a of the EVP unit 13 (normal operation control) when the pressure in the constant pressure chamber of the brake booster 14 rises above a predetermined threshold (normal operation threshold: EVP ON threshold in Figures 2 to 5). Here, rising above the normal operation threshold means approaching atmospheric pressure from that threshold. The normal operation threshold is preset based on experiments within the pressure range between the pressure achievable when the constant pressure chamber is evacuated by the pump 13a (limit negative pressure) and atmospheric pressure.

[0030] Furthermore, after driving the pump 13a, the CPU 11c of the integrated control ECU 11 stops driving the pump 13a of the EVP unit 13 if the pressure in the constant pressure chamber of the brake booster 14 falls below a predetermined threshold (drive stop threshold). Here, falling below the drive stop threshold means approaching the vacuum pressure below that threshold. In this embodiment, the drive stop threshold is set to a value slightly higher (atmospheric pressure) than the pressure (limit negative pressure) that can be reached when the constant pressure chamber is evacuated by the pump 13a. Note that the drive stop threshold can be appropriately changed within the range between the normal drive threshold and the limit negative pressure.

[0031] (Special assistance) In this embodiment, when idle stop control is not being performed, if predetermined special driving conditions are met, the CPU 11c of the integrated control ECU 11 controls the driving of the pump 13a of the EVP unit 13, even if the pressure in the constant pressure chamber of the brake booster 14 is not higher than the normal driving threshold. In this embodiment, there are two predetermined special driving conditions, and the first special driving condition is that all of (a1) to (a3) ​​are satisfied, where (a1) the vehicle 1 is decelerating, (a2) the pressure in the constant pressure chamber of the brake booster 14 is higher than a predetermined threshold (the negative pressure has decreased to or below a predetermined threshold), and (a3) ​​it can be estimated that the vehicle is idling stop.

[0032] Whether or not vehicle 1 in (a1) is decelerating can be determined, for example, from the time-series change in vehicle speed output from vehicle speed sensor 8. Alternatively, the determination of whether or not vehicle 1 is decelerating may be made based on a decrease in the rotational speed of engine 3.

[0033] Whether the pressure in the constant pressure chamber of the brake booster 14 (a2) is higher than a predetermined threshold can be determined from the pressure in the constant pressure chamber output from the negative pressure sensor 20. Here, the predetermined threshold (special drive threshold) is the pressure at which the negative pressure in the constant pressure chamber is slightly lower than the engine negative pressure limit (limit engine negative pressure) supplied to the constant pressure chamber when the engine is running, and in this embodiment, it is set within the range between the limit engine negative pressure and the normal drive threshold.

[0034] (a3) The conditions under which it can be estimated that the vehicle will perform an idle stop are when the vehicle speed is below a predetermined value and the amount the brake pedal is depressed is above a predetermined amount. This is estimated, for example, from the output value from the vehicle speed sensor 8 and the brake pedal position sensor (not shown). The "predetermined value" for the vehicle speed being below a predetermined value is set to a value slightly greater than the vehicle speed at which idle stop control can be performed (for example, 9 km / h) (for example, 12 km / h). The "predetermined amount" for the amount the brake pedal is depressed is determined in advance through experimentation.

[0035] Furthermore, the second special driving condition is that all of (b1) and (b2) are satisfied, i.e., (b1) the idle stop control is in standby mode and (b2) it can be presumed that pumping the brakes has been performed.

[0036] Whether or not the idle stop control in (b1) is in standby mode can be determined, for example, by whether or not the output value from the vehicle speed sensor 8 is below a predetermined value, or by the degree of decrease in engine speed. Alternatively, if the CPU 11c of the integrated control ECU 11 manages the feasibility of idle stop control by setting an idle stop permission determination flag to ON / OFF, it can be determined whether or not the idle stop control is in standby mode based on the ON / OFF state of the flag. In this case, the idle stop permission determination flag is set to ON, for example, when none of the predetermined engine restart conditions (i) to (ix) are met and the vehicle speed is below a predetermined value, or when the degree of decrease in engine speed 3 is above a predetermined threshold.

[0037] Whether or not pumping the brakes (b2) was performed can be estimated from, for example, the time and frequency of the ON and OFF states of the stop lamp switch, the amount, time, and frequency of the change in brake fluid pressure, etc. For example, if the stop lamp switch switches between ON and OFF a predetermined number of times within a predetermined time, it may be estimated that pumping brakes have been performed. Alternatively, the duration of the ON state and the duration of the OFF state of the stop lamp switch can be detected to estimate whether or not pumping brakes have been performed. Furthermore, an upper and lower limit for determining the presence or absence of pumping brakes may be set for the brake fluid pressure, and it may be estimated that pumping brakes have been performed if the change from the upper limit to the lower limit and the change from the lower limit to the upper limit exceeds a predetermined number of times within a predetermined time. Alternatively, the repetition frequency of the change between the upper limit and the lower limit may be calculated from the period of the change from the upper limit to the lower limit and the change from the lower limit to the upper limit, and it may be estimated that pumping brakes have been performed if this frequency exceeds a predetermined threshold.

[0038] Next, with reference to Figures 2 to 5, the idle stop control of this embodiment will be explained in comparison with the idle stop control of the conventional technology.

[0039] (When the engine automatically shuts off after stopping + the brake is pressed again while the engine is off: Conventional) As shown in Figure 2(a), in the conventional technology, during the process of automatic engine stop control, the vehicle decelerates first when the driver switches from the accelerator pedal to the brake pedal (brake pedal operation is ON) (time T1). As a result, the negative pressure in the constant pressure chamber of the brake booster decreases, but it does not decrease to the threshold required to drive the EVP unit's pump (corresponding to the normal drive threshold in this embodiment). Therefore, the pump drive control is not performed at time T1.

[0040] The vehicle stops due to continued pressure on the brake pedal (time T2), and the engine stop condition is then met (time T3). At time T3, the engine is automatically shut down due to the meeting of the engine stop condition. At this time, the vehicle's current consumption decreases due to the engine shutdown. Also, because the brake pedal is still being pressed, the negative pressure in the constant pressure chamber of the brake booster at time T3 does not change significantly from time T1. Therefore, the negative pressure in the constant pressure chamber of the brake booster has not decreased to the threshold required to drive the EVP unit's pump (corresponding to the normal drive threshold in this embodiment), and the EVP unit's pump is not driven.

[0041] Suppose that at time T4, while the engine is under stop control (idle stop), the brake pedal is pressed again. In this case, the negative pressure in the brake booster's constant pressure chamber decreases further. As a result, at time T5, if the negative pressure in the brake booster's constant pressure chamber falls below the threshold for driving the EVP unit's pump (corresponding to the normal drive threshold in this embodiment), the EVP unit's pump is driven to assist the negative pressure. re ru.

[0042] When the pump is driven, the vehicle's current consumption increases. As a result, if the vehicle's current consumption exceeds the threshold for engine restart conditions, engine restart control is performed and the idle stop state is released. As described above, in conventional technology, even if idle stop is performed and engine stop control is performed after stopping, if the brake is pressed again afterward, the idle stop state may be released by driving the EVP unit's pump. This is not only due to pressing the brake pedal again, but also if the brake pedal is pressed further while the idle stop state is active, the pump may be driven and the idle stop state may be released due to the decrease in negative pressure in the constant pressure chamber.

[0043] (When the engine automatically shuts off after stopping + the brake is pressed again while the engine is off: This invention) As shown in Figure 2(b), in this embodiment, during the process of the engine 3 being automatically stopped, the vehicle 1 decelerates when the driver first switches from the accelerator pedal to the brake pedal 19 (operation of the brake pedal 19 is ON) (time T6). As a result, the negative pressure in the constant pressure chamber of the brake booster 14 decreases, but it does not decrease to the normal drive threshold required for the normal drive of the pump 13a of the EVP unit 13. Therefore, at time T1, the drive control of the pump 13a of the EVP unit 13 is not performed.

[0044] If the above-described first special drive condition is met, including the condition (a3) ​​that allows it to be estimated that vehicle 1 may perform an idle stop at time T7 during the deceleration process of vehicle 1 (before automatic engine stop: before idle stop control) due to continued pressing of the brake pedal 19, the pump 13a will be driven even if the negative pressure in the constant pressure chamber of the brake booster 14 has not decreased to the normal drive threshold for normal driving of the pump 13a of the EVP unit 13. Although the driving of the pump 13a increases the current consumption of vehicle 1, since it is before idle stop (engine 3 is ON), the engine will not be restarted even if it increases above the threshold for engine restart. The driving of the pump 13a will continue until the negative pressure in the constant pressure chamber of the brake booster 14 recovers to a predetermined value or higher, and the current consumption of vehicle 1 will increase during this time.

[0045] Subsequently, if vehicle 1 stops and the engine stop condition is met at time T8, automatic engine stop control is performed. Consequently, the current consumption of vehicle 1 decreases. Next, suppose that at time T9, the brake pedal 19 is pressed again while the engine is in stop control (idling stop). In this case, at time T10, the negative pressure in the constant pressure chamber of the brake booster 14 decreases, but at time T7, the drive control of the pump 13a (special drive control) is performed, so the negative pressure in the constant pressure chamber of the brake booster 14 recovers by time T8. Therefore, at time T10, it does not decrease to below the normal drive threshold, and the drive control of the pump 13a is not performed. In other words, even if the brake pedal 19 is pressed again during idling stop, the current consumption of vehicle 1 does not increase to the threshold required for engine restart, and idling stop control continues.

[0046] With this configuration, even if the brake pedal 19 is pressed again, or if the brake pedal 19 is pressed further while the engine is idle, the engine will not be driven by the pump 13a due to a decrease in the negative pressure in the constant pressure chamber, and the idle stop control will continue.

[0047] (When the engine automatically shuts off while driving + the brake is pressed again while the engine is off: Conventional) As shown in Figure 3(a), in the conventional technology, during the process of automatic engine stop control, the vehicle decelerates first when the driver switches from the accelerator pedal to the brake pedal (brake pedal operation is ON) (time T20). As a result, the negative pressure in the constant pressure chamber of the brake booster decreases, but it does not decrease to the threshold required to drive the EVP unit's pump (corresponding to the normal drive threshold in this embodiment). Therefore, the pump drive control is not performed at time T20.

[0048] If the brake pedal remains depressed, and at time T21 during the vehicle 1's deceleration process, the brake pedal depression amount exceeds a predetermined amount, and the vehicle speed decelerates to a predetermined value (e.g., 9 km / h), the engine stop condition is met, and the engine is automatically stopped by idle stop control. Consequently, the vehicle's current consumption decreases. Also, because the brake pedal remains depressed, the negative pressure in the brake booster's constant pressure chamber at time T21 does not change significantly from time T20. Therefore, the negative pressure in the brake booster's constant pressure chamber has not decreased to the threshold required to drive the EVP unit's pump (corresponding to the normal drive threshold in this embodiment), and the EVP unit's pump is not driven.

[0049] Suppose that after the vehicle comes to a stop during idle stop, the brake pedal is pressed again at time T22. In this case, the negative pressure in the brake booster's constant pressure chamber decreases further. As a result, if at time T23 the negative pressure in the brake booster's constant pressure chamber falls below the threshold for driving the EVP unit's pump (corresponding to the normal drive threshold in this embodiment), the EVP unit's pump drive control is performed to assist the negative pressure. re ru.

[0050] When the pump is driven, the vehicle's current consumption increases. As a result, if the vehicle's current consumption exceeds the threshold for engine restart conditions, engine restart control is performed and the idle stop state is released (time T23). As described above, in conventional technology, even if idle stop is performed and engine stop control is performed while driving, if the brake is pressed again after the vehicle has stopped, the idle stop state may be released by driving the EVP unit's pump. This is because, not only if the brake pedal is pressed again, but also if the brake pedal is pressed further during idle stop, the pump may be driven and the idle stop state may be released due to the decrease in negative pressure in the constant pressure chamber.

[0051] (When the engine automatically stops while driving + the brake is pressed again while the engine is stopped: This invention) As shown in Figure 3(b), in this embodiment, during the process of the engine 3 being automatically stopped, the vehicle 1 decelerates when the driver first switches from the accelerator pedal to the brake pedal 19 (operation of the brake pedal 19 is ON) (time T30). As a result, the negative pressure in the constant pressure chamber of the brake booster 14 decreases, but it does not decrease to the normal drive threshold required for the normal drive of the pump 13a of the EVP unit 13. Therefore, at time T30, the drive control of the pump 13a of the EVP unit 13 is not performed.

[0052] If the above-described first special drive condition is met, which includes a condition (a3) ​​that allows it to be estimated that vehicle 1 may perform an idle stop at time T31 during the deceleration process of vehicle 1 (before automatic engine stop: before idle stop control) due to continued pressing of the brake pedal 19, then the drive control (special drive control) of pump 13a will be performed even if the negative pressure in the constant pressure chamber of brake booster 14 has not decreased to the normal drive threshold for normal drive of pump 13a of EVP unit 13. Although the current consumption of vehicle 1 increases due to the drive of pump 13a, since it is before idle stop (engine 3 is ON), engine 3 will not be restarted even if it increases above the threshold for engine restart. The drive of pump 13a will continue until the negative pressure in the constant pressure chamber of brake booster 14 recovers to a predetermined value or higher, and during this time the current consumption of vehicle 1 will increase.

[0053] If the brake pedal 19 continues to be pressed, and at time T32 during the vehicle 1's deceleration process, the amount of pressure applied to the brake pedal 19 is greater than or equal to a predetermined amount, and the vehicle speed decelerates to a predetermined value (for example, 9 km / h), the engine stop condition is met, and the engine 3 is automatically stopped by idle stop control. Consequently, the current consumption of the vehicle 1 decreases. Also, because the brake pedal 19 continues to be pressed, the negative pressure in the constant pressure chamber of the brake booster 14 at time T32 remains virtually unchanged from time T31.

[0054] Suppose that after vehicle 1 stops during idle stop, the brake pedal 19 is pressed again at time T33. In this case, the negative pressure in the constant pressure chamber of the brake booster 14 decreases at time T34, but because the drive control (special drive control) of the pump 13a is performed at time T31, the negative pressure in the constant pressure chamber of the brake booster 14 recovers by time T32. Therefore, it does not decrease to below the normal drive threshold at time T34, and the drive control of the pump 13a is not performed. In other words, even if the brake pedal 19 is pressed again during idle stop, the current consumption of vehicle 1 does not increase to the threshold required to restart engine 3, and the idle stop control continues.

[0055] With this configuration, even if the brake pedal 19 is pressed again, or if the brake pedal 19 is pressed further while the engine is idle stop, the engine will not be driven by the pump 13a due to a decrease in the negative pressure in the constant pressure chamber, and the idle stop control will continue.

[0056] (When the engine automatically shuts off after stopping + when pumping the brakes is performed before the engine shuts off: Conventional) As shown in Figure 4(a), in the conventional technology, during the process of automatic engine stop control, the vehicle decelerates first when the driver switches from the accelerator pedal to the brake pedal (brake pedal operation is ON) (time T41). At this time, it is assumed that pumping brakes is performed, in which the brake pedal is pressed down and released repeatedly in a short period of time.

[0057] In this case, each time the brake pedal is pressed down and released, the negative pressure in the constant pressure chamber of the brake booster decreases, resulting in a significant decrease in the negative pressure in the constant pressure chamber. If the negative pressure in the constant pressure chamber of the brake booster falls below the threshold required to drive the EVP unit's pump (corresponding to the normal drive threshold in this embodiment), the EVP unit's pump is driven to compensate for the negative pressure (time T42). When the pump is driven, the vehicle's current consumption increases.

[0058] Suppose the pumping brakes are then stopped and the vehicle comes to a stop as normal brake pedal pressure continues. Then, at time T43, when the engine stop condition is met, the engine is automatically shut down. Because the pumping brakes have significantly reduced the negative pressure in the brake booster's constant pressure chamber, the pump may not have finished restoring the negative pressure by time T43 when the engine stop condition is met. In this case, since the pump is still being driven at time T43, the vehicle's current consumption may also exceed the threshold required for the engine restart condition.

[0059] In such cases, the engine is restarted and the idle stop control is immediately deactivated (time T44). As described above, with conventional technology, if pumping brakes are performed during the vehicle's deceleration process, the automatic engine stop control may be instantly deactivated even if idle stop control is subsequently activated.

[0060] (When the engine automatically shuts off after stopping + when the pumping brakes are applied before the engine shuts off: This invention) As shown in Figure 4(b), in this embodiment, during the process of the engine 3 being automatically stopped, the vehicle decelerates first when the driver switches from the accelerator pedal to the brake pedal 19 (operation of the brake pedal 19 is ON) (time T51).

[0061] Subsequently, if pumping the brakes is performed, the negative pressure in the constant pressure chamber of the brake booster decreases each time the brake pedal is pressed down and released (each time a pumping brake cycle is performed). Here, if a second special drive condition is met, including the condition (b2) that allows us to estimate that pumping the brakes was performed at time T52, the drive control of the pump 13a is performed even if the negative pressure in the constant pressure chamber of the brake booster 14 has not decreased to the normal drive threshold required for the normal drive of the pump 13a of the EVP unit 13. The drive of the pump 13a increases the current consumption of the vehicle 1, but since it is before the idle stop (engine 3 is ON), even if it increases above the threshold required for engine restart, the event of engine 3 restarting will not occur. The drive of the pump 13a continues until the amount of negative pressure in the constant pressure chamber of the brake booster 14 recovers to above a predetermined value (time T53), and during this time the current consumption of the vehicle 1 increases.

[0062] Assume that after the pumping brake is stopped, the negative pressure in the constant pressure chamber has finished recovering, and the vehicle 1 has stopped due to the continued pressing of the normal brake pedal 19. Then, at time T54, if the engine stop conditions are met while the vehicle 1 is stopped, the engine will be automatically shut down. Consequently, the current consumption of the vehicle 1 will decrease.

[0063] Next, let's assume that at time T55, while the engine is being stopped (idling stop), the brake pedal 19 is pressed again. In this case, at time T56, the negative pressure in the constant pressure chamber of the brake booster 14 decreases, but at time T52, the drive control of the pump 13a (special drive control) is performed, and by time T53, the negative pressure in the constant pressure chamber of the brake booster 14 has recovered. Therefore, at time T56, it does not decrease to below the normal drive threshold, and the drive control of the pump 13a is not performed (idling stop control continues).

[0064] As described above, in this embodiment, even if pumping the brakes occurs before idle stop control, the engine 3 will not be instantly restarted after the conditions for stopping the engine 3 are met and the engine 3 automatically stops. Furthermore, even if the brake pedal 19 is pressed again during idle stop control, the current consumption of the vehicle 1 will not increase to the threshold required for engine restart, and the idle stop control will continue.

[0065] Furthermore, with this configuration, even if the brake pedal 19 is pressed further during idle stop, the pump 13a is not driven due to a decrease in the negative pressure in the constant pressure chamber, and the idle stop control continues.

[0066] (When the engine automatically shuts off while driving + when pumping the brakes is performed before the engine shuts off: Conventional) As shown in Figure 5(a), in the conventional technology, during the process of automatic engine stop control, it is assumed that at time T61 the driver first switches from the accelerator pedal to the brake pedal (brake pedal operation is ON), and then pumping brakes is performed. In this case, each time the brake pedal is pressed down and released, the negative pressure in the constant pressure chamber of the brake booster decreases, resulting in a significant decrease in the negative pressure in the constant pressure chamber. If the negative pressure in the constant pressure chamber of the brake booster falls below the threshold for driving the EVP unit's pump (corresponding to the normal drive threshold in this embodiment), the EVP unit's pump is driven to assist the negative pressure (time T62). When the pump is driven, the vehicle's current consumption increases. The pump continues to be driven until time T65 when the amount of negative pressure in the brake booster's constant pressure chamber recovers to above a predetermined value, and during this time, the vehicle's current consumption increases.

[0067] Suppose the pumping brakes are then stopped, and the vehicle continues to decelerate with the brake pedal pressed down normally. At time T63, when the engine stop condition is met, the engine is automatically shut down. Because the pumping brakes have significantly reduced the negative pressure in the brake booster's constant pressure chamber, the pump may not have fully restored the negative pressure by time T63, when the engine stop condition is met while the vehicle is decelerating and before coming to a complete stop. In this case, since the pump is still being driven at time T63, the vehicle's current consumption may also exceed the threshold required for the engine restart condition.

[0068] In such cases, the engine restarts instantly after being stopped, and the idle stop control is immediately deactivated (time T64).

[0069] (When the engine automatically shuts off while driving and the pumping brakes are applied before the engine shuts off: This invention) As shown in Figure 5(b), in this embodiment, during the process of the engine 3 being automatically stopped, first, at time T71, the driver switches from the accelerator pedal to the brake pedal 19 (operation of the brake pedal 19 is ON), and then pumping the brakes is performed. In this case, each time the brake pedal 19 is pressed down and released, the negative pressure in the constant pressure chamber of the brake booster 14 decreases.

[0070] Here, if a second special drive condition is met, including the condition (b2) under which it can be estimated that pumping brakes was performed at time T72, the drive control of the pump 13a is performed even if the negative pressure in the constant pressure chamber of the brake booster 14 has not decreased to the normal drive threshold for normal drive of the pump 13a of the EVP unit 13. Although the current consumption of the vehicle 1 increases due to the drive of the pump 13a, since it is before the idle stop (engine 3 is ON), even if it increases above the threshold for engine restart, the event of engine 3 restarting will not occur. The drive of the pump 13a continues until time T73 when the negative pressure in the constant pressure chamber of the brake booster 14 recovers to above a predetermined value, and during this time the current consumption of the vehicle 1 increases.

[0071] Subsequently, assume that the pumping brakes are stopped and the vehicle is decelerating with the normal brake pedal pressure maintained. Then, at time T74, while vehicle 1 is decelerating, if the engine stop conditions are met, the engine will be automatically shut down. Consequently, the current consumption of vehicle 1 will decrease.

[0072] Next, let's assume that at time T75, while the engine is being stopped (idling stop), the brake pedal 19 is pressed again. In this case, at time T76, the negative pressure in the constant pressure chamber of the brake booster 14 decreases, but because the pump 13a is being driven (special drive control) at time T72, the negative pressure in the constant pressure chamber of the brake booster 14 recovers by time T73. Therefore, at time T76, it does not decrease to below the normal drive threshold, and the pump 13a is not driven (idling stop control continues).

[0073] As described above, in this embodiment, even if pumping the brakes occurs before idle stop control, the engine 3 will not be instantly restarted after the engine 3 automatically stops when the conditions for stopping the engine are met. Furthermore, even if the brake pedal 19 is pressed again during idle stop control, the pump 13a is not driven, so the current consumption of the vehicle 1 does not increase to the threshold required for engine restart, and idle stop control continues.

[0074] Furthermore, with this configuration, even if the brake pedal 19 is pressed further during idle stop, the pump 13a is not driven due to a decrease in the negative pressure in the constant pressure chamber, and the idle stop control continues.

[0075] Therefore, according to this embodiment, even before the negative pressure in the constant pressure chamber of the brake booster 14 falls below the normal drive threshold, if a special drive condition (first special drive condition) is met during deceleration of the vehicle 1, the drive control of the pump 13a is performed and auxiliary negative pressure is supplied to the constant pressure chamber of the brake booster 14. In this way, even if the brake pedal 19 is pressed again or pressed further while the engine 3 is automatically stopped (idling stop), causing the negative pressure in the constant pressure chamber to decrease, it is less likely to fall below the normal drive threshold at which the drive control of the pump 13a is performed. Therefore, it is less likely to exceed the threshold of current consumption required for the restart condition of the engine 3 during idling stop, improving the continuity of idling stop, and consequently improving the fuel efficiency of the vehicle 1.

[0076] Even before the negative pressure in the constant pressure chamber of the brake booster 14 falls below the normal drive threshold, if a special drive condition (second special drive condition) is met before idle stop control, the pump 13a is driven to supply auxiliary negative pressure to the constant pressure chamber of the brake booster 14. In this way, even if pumping the brakes is performed before idle stop control, the engine 3 is restarted after idle stop control, preventing the idle stop control from being instantly canceled. Furthermore, even if the brake pedal 19 is pressed again or pressed further while the engine 3 is automatically stopped (during idle stop control), causing the negative pressure in the constant pressure chamber to decrease, it is unlikely to fall below the normal drive threshold at which the pump 13a is driven. Therefore, it becomes less likely to exceed the current consumption threshold required for the engine 3 restart condition during idle stop, improving the continuity of idle stop, and consequently improving the fuel efficiency of the vehicle 1.

[0077] Furthermore, by making the pump 13a of the EVP unit 13 an electrically operated vacuum pump that consumes current when driven, the significance of raising the vacuum in the constant pressure chamber of the brake booster 14 in advance before idle stop control, thereby making it more difficult to drive the pump 13a of the EVP unit 13, is enhanced.

[0078] It should be noted that the present invention is not limited to the embodiments described above, and various modifications can be made without departing from the spirit of the invention. For example, in the embodiments described above, the idle stop control may be executed even before the vehicle 1 comes to a complete stop (for example, when the vehicle speed is 9 km / h or less), but the idle stop control may be configured not to be executed until the vehicle 1 has come to a complete stop. In this case, the condition (a3) ​​for which the vehicle is estimated to perform an idle stop in the first special driving condition may be, for example, when the vehicle speed is 3 km / h or less and the amount the brake pedal is depressed is 100% or more.

[0079] Furthermore, in the above-described embodiment, various processes are performed by a single ECU (integrated control ECU 11), but for example, the EFI control unit, idle stop control unit, CVT control unit, ABS / VSC control unit, and EVP control unit may be configured as separate ECUs. In this case, for example, each ECU may exchange necessary information with each other via a communication bus such as CAN.

[0080] Furthermore, the above-described embodiments can be applied not only to gasoline-powered vehicles, but also to electric vehicles, hybrid vehicles, and autonomous vehicles.

[0081] Furthermore, the present invention can be applied to a vehicle equipped with a control means that stops an operating engine when a predetermined automatic engine stop condition is met, and automatically restarts a stopped engine when a predetermined engine restart condition is met. [Explanation of Symbols]

[0082] 1. Idling stop vehicle 11. Integrated Control ECU (Negative Pressure Assistance Means) 14. Brake booster (brake assist device) 13 EVP unit (negative pressure assisting means) 13a Pump

Claims

1. In a vehicle control device that automatically stops the running engine when the vehicle decelerates to a predetermined speed by pressing the brake pedal and a predetermined automatic engine stop condition is met, and automatically restarts the stopped engine when a predetermined engine restart condition is met, A brake assist mechanism that uses engine vacuum to assist the brakes, A negative pressure assisting means that supplies auxiliary negative pressure to the brake assisting means by controlling the drive of the pump, Equipped with, The predetermined engine restart condition includes the vehicle's current consumption, including the current required to drive the pump, exceeding a threshold value related to the engine restart condition. The aforementioned negative pressure assisting means is When the normal operating condition is met, in which the negative pressure of the brake assist means is higher than a predetermined drive stop threshold value that is higher on the atmospheric pressure side than the limit negative pressure that can be reached by driving the pump, the pump is driven to supply the assist negative pressure, If, while the vehicle is decelerating, it is estimated that the predetermined automatic engine stop condition will be met before the normal driving condition is met, the first special driving condition will be assumed to be met, and the pump will be driven to supply the auxiliary negative pressure, thereby increasing the negative pressure of the brake assist means before the predetermined automatic engine stop condition is met, and after the predetermined automatic engine stop condition is met, the drive control of the pump will be such that the current consumption does not exceed the threshold related to the engine restart condition. A vehicle control device characterized by the following features.

2. The aforementioned negative pressure assisting means is The vehicle control device according to claim 1, characterized in that, when the vehicle is decelerating, before the normal driving conditions are met, and when it can be estimated that a second special driving condition, which is pumping brakes, is performed while the engine is in standby mode for stopping based on the fulfillment of the predetermined automatic engine stop conditions, the pump is driven to supply the auxiliary negative pressure, thereby raising the negative pressure of the brake assist means before the predetermined automatic engine stop conditions are met, and after the predetermined automatic engine stop conditions are met, the drive control of the pump prevents the current consumption from exceeding the threshold related to the engine restart conditions.

3. The vehicle control device according to claim 1 or 2, characterized in that the pump is an electrically operated vacuum pump.

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