JP2023158757A - Vehicle control device - Google Patents

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, when negative pressure of a brake booster 14 becomes lower than a normal drive threshold, drive control of a pump 13a of a brake booster 14 is executed, while the idling stop control is in execution, within a range in which an engine restart condition related to consumption current of a vehicle 1 is not met. Thus, the vehicle control device can prevent the negative pressure of the brake booster 14 from becoming lower than a threshold related to the restart condition of the engine 3. Also, driving of the pump 13a can prevent the consumption current of the vehicle 1 from exceeding the threshold related to the restart condition of the engine 3.SELECTED DRAWING: Figure 1

Description

This invention provides a vehicle control system that includes a control means that stops a running engine when a predetermined automatic engine stop condition is met, and automatically restarts a stopped engine when a predetermined engine restart condition is met. Regarding equipment.

BACKGROUND ART Conventionally, a vehicle has been proposed that automatically stops idling of an engine when a predetermined idling-stop starting condition is satisfied (see, for example, Patent Document 1). Here, the predetermined idling stop starting conditions are: (i) the vehicle is stopped; (ii) the battery capacity is greater than or equal to a predetermined amount; (iii) the temperature of the engine cooling water is greater than or equal to a predetermined value. iv) It is exemplified that all conditions such as the difference between the set temperature of the air conditioner and the temperature inside the vehicle are equal to or less than a predetermined value are satisfied.

JP2020-84961A

By the way, vehicles are equipped with a brake booster to assist the operating force of the brake pedal, but since the brake booster uses engine negative pressure, when the engine is stopped or at low rotation speeds, the engine negative pressure is reduced. There is a possibility that the desired braking force may not be obtained due to the decrease in braking force. Therefore, when engine negative pressure decreases, there is an electric negative pressure pump system (EVP system) that supplies negative pressure to a brake booster using an electric pump to compensate for the decrease.

In idling stop vehicles equipped with an electric negative pressure pump system, if the negative pressure in the brake booster falls below the threshold while the engine is not idling, the electric negative pressure pump is activated to pump up the brake booster. Control is performed to increase the negative pressure. In addition, in idling stop vehicles, the engine automatically restarts if a predetermined engine restart condition is met during idling stop, but the condition may be set such that the vehicle's current consumption exceeds a threshold value. . In this case, if the electric negative pressure pump is driven during the idling stop, the current consumption exceeds the threshold value, the idling stop is canceled, and the efficiency of improving fuel efficiency deteriorates.

This invention was made in view of the above problems, and aims to improve fuel efficiency by improving the continuity of idling stop.

In order to achieve the above object, the vehicle control device of the present invention stops a running engine when a predetermined engine automatic stop condition is met, and stops a running engine when a predetermined engine restart condition is met. In a vehicle control device that automatically restarts the brake system, there is a brake auxiliary means that assists the brake using engine negative pressure, and a brake auxiliary means that supplies auxiliary negative pressure to the brake auxiliary means by controlling the drive of a pump. pressure auxiliary means, the predetermined engine restart condition includes that the current consumption of the vehicle including the current required to drive the pump exceeds a predetermined threshold, and the negative pressure auxiliary means When supplying auxiliary negative pressure to the brake auxiliary means in a stopped state, the pump is driven within a range that does not exceed the predetermined threshold value (claim 1).

Further, the pump may be an electric negative pressure pump driven by a motor (claim 2).

Further, the negative pressure auxiliary means may drive the pump when it is determined that the current consumption of the vehicle does not exceed the predetermined threshold even if the pump is driven. .

In addition, when the negative pressure auxiliary means supplies auxiliary negative pressure to the brake auxiliary means during automatic stop of the engine, the current consumption of the vehicle when driving the pump exceeds the predetermined threshold value. The on/off cycle of the voltage applied to the pump is adjusted so as not to exceed the voltage applied to the pump (Claim 4).

According to the invention of claim 1, when the negative pressure auxiliary means supplies auxiliary negative pressure to the brake auxiliary means in a state where the engine is automatically stopped (idling stop state), the current consumption of the vehicle is reduced by the amount of current consumed by the vehicle to restart the engine. Since the pump is driven within a range that does not exceed the threshold applied to the brake, it is possible to prevent the vehicle's current consumption from exceeding a predetermined threshold and canceling the idling stop state when supplying auxiliary negative pressure to the brake auxiliary means. Improves stop continuity. Furthermore, by improving the continuity of idling stop, the fuel efficiency of the vehicle improves.

According to the second aspect of the invention, by using the pump as an electric negative pressure pump, it becomes easy to adjust the current consumption of the vehicle when supplying auxiliary negative pressure to the brake auxiliary means.

According to the invention of claim 3, when the negative pressure auxiliary means is driven, the current consumption of the vehicle exceeds a predetermined threshold value and the engine restarts, the pump is not driven. Restarts can be reliably prevented.

According to the fourth aspect of the invention, it is possible to improve the continuity of idling stop while supplying auxiliary negative pressure to the brake auxiliary means, thereby improving the fuel efficiency of the vehicle.

1 is a block diagram of an embodiment of a vehicle control device of the present invention. FIG. 4 is a diagram comparing a timing chart of each parameter when the brake is pressed again during idling stop after stopping the vehicle with a conventional timing chart.

Next, in order to explain the present invention in more detail, an embodiment in which the present invention is applied to an idling stop vehicle will be described in detail with reference to FIGS. 1 and 2.

Figure 1 shows the block configuration of a vehicle control device equipped in an idling stop vehicle 1 (sometimes referred to as vehicle 1). It is equipped with one lead battery 2 with a small capacity. The negative terminal of this battery 2 is connected to the body of the idling stop vehicle 1 and grounded. Note that a current sensor (not shown) is connected to the battery 2, and measures the current consumption of the vehicle 1 at predetermined intervals (for example, 10 ms).

In FIG. 1, 3 is an engine of an 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 and the engine 3.

A starter 6 starts the engine 3, and is supplied with power from the battery 2 via a relay 7. Reference numeral 9 denotes 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 the belt 10, which charges the battery 2 with the generated output during driving etc., and operates under predetermined conditions. It operates as a motor and generates driving force for the idling stop vehicle 1.

The relay 7 has a relay coil 7a and a relay switch 7b, and when current flows through the relay coil 7a, the relay switch 7b is turned on, the starter 6 is supplied with power from the battery 2, and the engine 3 is started. Furthermore, when the relay coil 7a is no longer energized, the relay switch 7b is turned off, and power supply to the starter 6 is stopped.

11 calculates a required torque based on the accelerator opening degree detected by an accelerator sensor (not shown), and controls the fuel injection amount, intake air amount, ignition timing, etc. of the engine 3 in order to output this required torque. An EFI control section, an idling stop control section that controls idling stop control, a CVT control section that controls CVT control, an ABS/VSC control section that prevents sideslip and spin, and a pump 13a (negative pressure pump) of the EVP unit 13. This is an integrated control ECU that is integrated with an EVP control unit that controls drive control. In addition, there is an engine ECU that controls the engine, an ISGECU that controls the ISG, etc. (not shown), and each ECU is formed of a microcomputer, etc., and exchanges information via a communication bus (not shown) such as CAN. do.

The integrated control ECU 11 is connected to a first driver IC 11a that is connected to one end of the relay coil 7a and functions as a switch for connecting the one end to the battery 2, and is connected to the other end of the relay coil 7a and connects the other end to the battery 2. It is equipped with a second driver IC 11b that functions as a switch for determining whether or not to ground, and a CPU 11c that controls these ICs 11a and 11b and other controls, and restarts the engine 3 after idling stop, which will be described later, and controls the brake booster 14. The pump 13a of the EVP unit 13 for supplementary supply of negative pressure is controlled.

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

The EVP unit 13 supplies negative pressure to compensate for a decrease in the value of the negative pressure in the constant pressure chamber of the brake booster 14, and includes a pump 13a. The pump 13a is, for example, an electric negative pressure pump, and when driven, sucks the gas in the constant pressure chamber of the brake booster 14 to make the constant pressure chamber a negative pressure lower than atmospheric pressure (supplies negative pressure). In this embodiment, the EVP unit 13 and the integrated control ECU 11 are electrically connected, and the CPU 11c of the integrated control ECU 11 controls the drive of the pump 13a.

(idling stop control)
Here, the general control and operation of the idling stop vehicle 1 will be explained. Regarding starting of the engine 3 by the driver, when the ignition (IG) key switch 17 is turned on (engine start command) with the shift lever (not shown) in the P range or N range, the IG key switch is turned on. 17 is input to the CPU 11c of the integrated control ECU 11, and based on this input, the CPU 11c instantaneously energizes the relay 7 to turn it on. As a result, the power from the battery 2 is supplied to the starter 6 to start the starter 6 and start the stopped engine 3 (initial start).

Once the engine 3 has started and the battery 2 has been fully charged by the power generated by the ISG, the CPU 11c of the integrated control ECU 11 will stop the engine from idling until the engine 3 is stopped by turning off the IG key switch 17. Execute control.

Vehicle speed information from the vehicle speed sensor 8, shift position information from the shift range switch 16, negative pressure information from the negative pressure sensor 20, etc. are input to the CPU 11c of the integrated control ECU 11. Information on the engine 3 such as engine speed and cooling water temperature, information on battery 2 current and temperature, information on master cylinder pressure, lock-up clutch information, stop lamp switch, courtesy switch, etc. are also transmitted via the communication bus. Information on switches in various parts of the car is also input.

Then, based on this information, the CPU 11c of the integrated control ECU 11 during idling stop control instructs the engine ECU to stop the engine when a predetermined engine stop condition is met, and the engine ECU throttles the fuel to stop the engine. 3 will automatically stop. Here, the predetermined engine stop condition is, for example, when the driver depresses the brake pedal 19 in accordance with a red traffic light, etc., and the master cylinder pressure exceeds a predetermined depression pressure (the amount of depression of the brake pedal exceeds a predetermined value). and, for example, the stop lamp is on and the vehicle 1 is decelerated to a predetermined vehicle speed (for example, 9 km/h or less).

Whether or not the master cylinder pressure is equal to or higher than a predetermined depression pressure can be determined, for example, based on a detected value of a brake pedal position sensor (not shown) that detects the position of the brake pedal. Further, whether or not the vehicle 1 is decelerating to a predetermined vehicle speed can be determined based on the output value from the vehicle speed sensor 8, for example.

Next, when a predetermined engine restart condition is met during idling stop, the CPU 11c of the integrated control ECU 11 instantaneously energizes the relay 7 to turn it on, supplies power from the battery 2 to the starter 6, and starts the starter 6. To start and automatically restart a stopped engine 3.
The predetermined engine restart condition is, for example,
(i) When the driver releases the brake pedal 19 and the amount of depression of the brake pedal 19 becomes less than a predetermined threshold (ii) When the shift position information from the shift range switch 16 changes from "D range" or "N 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 depressed (accelerator (When the amount of pedal depression is greater than a predetermined value)
(v) When the current consumption is more than 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's seat is seated with the seat belt (ix) When steering operation is detected (x) When the pressure in the constant pressure chamber of the brake booster is higher than a predetermined value In this case, the CPU 11c of the integrated control ECU 11 performs automatic start control of the engine 3 (engine restart control).

(Negative pressure assistance by electric negative pressure pump)
When the pressure in the constant pressure chamber of the brake booster 14 becomes higher than a predetermined threshold (normal drive threshold: EVP ON threshold in FIG. 2) when the idling stop control is not performed, the CPU 11c of the integrated control ECU 11 controls the following: Drive control of the pump 13a of the EVP unit 13 is performed.

However, when the idling stop control is being performed, the CPU 11c of the integrated control ECU 11 controls when the pressure in the constant pressure chamber of the brake booster 14 becomes higher than a predetermined threshold (normal drive threshold: EVP ON threshold in FIG. 2). After determining whether or not to perform drive control of the pump 13a of the EVP unit 13, the drive control of the pump 13a is performed. Here, becoming higher than the normal drive threshold means getting closer to atmospheric pressure than the threshold. The normal drive threshold is preset based on experiments within the pressure range between the pressure that can be reached when the constant pressure chamber is evacuated using the pump 13a (limit negative pressure) and the threshold required for restarting the engine. has been done.

Specifically, when the pressure in the constant pressure chamber of the brake booster 14 becomes higher than a predetermined threshold (normal drive threshold: EVP ON threshold in FIG. 2) during idling stop control, the CPU 11c of the integrated control ECU 11 Based on the current consumption of the vehicle 1 output from the current sensor, it is determined whether or not to perform drive control of the pump 13a of the EVP unit 13.

There is a correlation between the magnitude of the negative pressure in the constant pressure chamber of the brake booster 14 and the current value consumed when the pump 13a of the EVP unit 13 is driven. It is possible to experimentally estimate how much current is required to drive the pump 13a of the EVP unit 13 when the drive threshold (EVP ON threshold in FIG. 2) is reached (estimated required consumption). current). In this embodiment, the value of the estimated required current consumption is stored in the memory of the integrated control ECU 11.

When the pressure in the constant pressure chamber of the brake booster 14 becomes higher than a predetermined threshold (normal drive threshold: EVP ON threshold in FIG. 2), the CPU 11c of the integrated control ECU 11 controls the voltage of the vehicle 1 output from the current sensor at that time. It is determined whether the total value of the current consumption value and the estimated required current consumption value exceeds a threshold value (idling stop release threshold value) of the current consumption of the vehicle 1 required for restarting the engine 3. Note that the CPU 11c of the integrated control ECU 11 acquires information regarding the current consumption of the vehicle 1 at a predetermined period (for example, 30 ms).

When it is determined that the total value of the current consumption of the vehicle 1 and the estimated required current consumption exceeds the threshold of the current consumption of the vehicle 1 required for restarting the engine 3 (idling stop cancellation threshold), the CPU 11c of the integrated control ECU 11 Even though the pressure in the constant pressure chamber of the brake booster 14 is higher than the normal drive threshold, the drive of the pump 13a of the EVP unit 13 is inhibited. That is, if the CPU 11c of the integrated control ECU 11 determines that the total value of the current consumption of the vehicle 1 and the estimated necessary current consumption exceeds the idling stop release threshold, the negative pressure in the constant pressure chamber of the brake booster 14 is set to normal drive. Even if the amount decreases below the threshold value, driving of the pump 13a is prohibited. In this case, since the pump 13a is not driven, the current consumption of the vehicle 1 does not exceed the idling stop cancellation threshold.

If it is determined that the total value of the current consumption of the vehicle 1 and the estimated necessary current consumption does not exceed the threshold of the current consumption of the vehicle 1 required for restarting the engine 3 (idling stop release threshold), the CPU 11c of the integrated control ECU 11 controls the drive of the pump 13a of the EVP unit 13. In this case, even if the negative pressure of the brake booster 14 decreases below the threshold (normal drive threshold) and the pump 13a of the EVP unit 13 is driven, the current consumption of the vehicle 1 will decrease below the idling stop release threshold (the current consumption of the vehicle 1). (based on the cancellation threshold).

When the total value of the current consumption of the vehicle 1 output from the current sensor and the estimated required current consumption becomes the same value as the threshold of the current consumption of the vehicle 1 required for restarting the engine 3 (idling stop cancellation threshold) , it can be arbitrarily set whether the CPU 11c of the integrated control ECU 11 executes drive control or prohibition control of the pump 13a.

Furthermore, when the CPU 11c of the integrated control ECU 11 controls the drive of the pump 13a, if the pressure in the constant pressure chamber of the brake booster 14 becomes lower than a predetermined threshold (drive stop threshold), the CPU 11c controls the EVP unit 13. Stop driving the pump 13a. Here, being lower than the drive stop threshold means being closer to the vacuum pressure than the threshold. In this embodiment, the drive stop threshold is set to a value slightly higher (pressure on the atmospheric pressure side) 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 changed as appropriate within the range between the normal drive threshold and the negative pressure limit.

Next, with reference to FIG. 2, the idling stop control of this embodiment will be described in comparison with the idling stop control of the prior art.

(When the engine automatically stops after stopping + the brake is pressed again while the engine is stopped: Conventional)
As shown in FIG. 2(a), in the conventional technology, in the process of automatically stopping the engine, the driver first switches from the accelerator pedal to the brake pedal (brake pedal operation is ON), and the vehicle decelerates (at the time T1). As a result, the negative pressure in the constant pressure chamber of the brake booster decreases, but it is assumed that it does not decrease to the threshold value for driving the pump of the EVP unit (corresponding to the normal drive threshold value in this embodiment). Therefore, drive control of the pump 13a is not performed at time T1.

Assume that the vehicle stops due to continued depression of the brake pedal (time T2), and then the engine stop condition is satisfied (time T3). At time T3, automatic engine stop control is performed when engine stop conditions are satisfied. At this time, the current consumption of the vehicle decreases due to the engine being stopped. Furthermore, since the brake pedal continues to be depressed, the amount of negative pressure in the constant pressure chamber of the brake booster at time T3 does not substantially change from time T1. Therefore, the negative pressure in the constant pressure chamber of the brake booster has not decreased to the threshold for driving the pump of the EVP unit (corresponding to the normal drive threshold in this embodiment), and the pump of the EVP unit is not driven.

Assume that the brake pedal is depressed again (first depression) during engine stop control (during idling stop) at time T4. In this case, the negative pressure in the constant pressure chamber of the brake booster is further reduced. As a result, if the negative pressure in the constant pressure chamber of the brake booster decreases below the threshold for driving the pump of the EVP unit (corresponding to the normal drive threshold in this embodiment) at time T5, the EVP is activated to supplement the negative pressure. Drive control of the unit's pump is performed. When the drive control of the pump is performed, the negative pressure in the constant pressure chamber of the brake booster increases, so that the negative pressure in the constant pressure chamber does not fall below the idling stop release threshold. Therefore, even if the brake pedal is depressed again during the idling stop control, the idling stop control is not canceled based on the decrease in the negative pressure in the constant pressure chamber.

On the other hand, when the pump drive control is performed, the current consumption of the vehicle increases, but the amount of decrease in negative pressure in the constant pressure chamber is relatively small in the first re-depression, and the current consumption of the vehicle increases due to the drive control of the pump. Assume that the current does not exceed the idling stop release threshold (the release threshold due to current consumption). In this case, idling stop control is maintained.

If the brake pedal is frequently pressed again in a short period of time, the negative pressure in the constant pressure chamber of the brake booster will decrease significantly. In this case, the drive load on the pump to compensate for the decrease in negative pressure increases, resulting in an increase in current consumption. Therefore, when the second pedal depression is performed at time T6, the current consumption of the vehicle further increases. As a result, if the current consumption of the vehicle exceeds the idling stop cancellation threshold at time T7, the idling stop control is canceled at time T7, and the engine is restarted. When the engine is restarted, the current consumption of the vehicle further increases as the ECU starts up.

The driving of the pump of the EVP unit is stopped when the negative pressure in the constant pressure chamber of the brake booster recovers to a predetermined threshold value (time T8), and the current consumption of the vehicle is accordingly reduced.

As described above, in the conventional technology, even if idling stop is performed after stopping and engine stop control is performed, if the brake is pressed again after that, the vehicle will stop due to the drive of the pump of the EVP unit. The idling stop state may be canceled due to an increase in current consumption. This applies not only when the brake pedal is pressed again, but also when the brake pedal is pressed more during idling, or when there is a change in the amount of brake pedal depression that the driver is not aware of. The pump may be activated due to a decrease in the negative pressure in the chamber, and the idling stop state may be canceled.

(When the engine automatically stops after stopping + the brake is pressed again while the engine is stopped: the present invention)
As shown in FIG. 2(b), in this embodiment, in the process of automatically stopping the engine 3, the driver first switches his/her foot from the accelerator pedal to the brake pedal 19 (the operation of the brake pedal 19 is turned on), thereby causing the vehicle to stop automatically. 1 decelerates (time T11). As a result, the negative pressure in the constant pressure chamber of the brake booster 14 decreases, but it is assumed that it does not decrease to the normal drive threshold for normal drive of the pump 13a of the EVP unit 13. Therefore, drive control of the pump 13a of the EVP unit 13 is not performed at time T11.

By continuing to press the brake pedal 19, the vehicle 1 stops at time T12, and when the engine 3 stop condition is satisfied at time T13, automatic stop control (idling stop control) of the engine 3 is performed. Accordingly, the current consumption of the vehicle 1 is reduced. Next, assume that the brake pedal 19 is pressed again at time T14 during engine stop control (during idling stop). It is assumed that, along with this, the negative pressure in the constant pressure chamber of the brake booster 14 decreases, and at time T15, it decreases to a normal drive threshold value at which drive control of the pump 13a of the EVP unit 13 is performed.

At this time, the CPU 11c of the integrated control ECU 11 determines that the total value of the current consumption of the vehicle 1 at that time and the estimated necessary current consumption stored in the memory in advance is the current consumption of the vehicle 1 required for restarting the engine 3. It is determined whether the threshold value (idling stop release threshold value) is exceeded. Here, if the CPU 11c of the integrated control ECU 11 determines that the total value does not exceed the idling stop release threshold (release threshold based on current consumption), it controls the drive of the pump 13a of the EVP unit 13 (see Fig. (See vehicle current consumption (i) in 2(b)).

As a result, the negative pressure in the constant pressure chamber of the brake booster 14 increases, so that the negative pressure does not fall below the idling stop release threshold (release threshold based on negative pressure), and idling due to the decrease in the negative pressure in the constant pressure chamber Release of stop control is avoided.

In addition, although the current consumption of the vehicle 1 increases due to the drive of the pump 13a, it does not exceed the idling stop cancellation threshold (a cancellation threshold based on current consumption), so that the idling stop control may not be canceled due to an increase in the current consumption of the vehicle 1. Avoided.

The drive control of the pump 13a of the EVP unit 13 is stopped when the negative pressure in the constant pressure chamber of the brake booster 14 recovers to a predetermined threshold value (time T16), and the current consumption of the vehicle is accordingly reduced.

Therefore, according to the present embodiment, when the negative pressure in the constant pressure chamber of the brake booster 14 decreases to the normal drive threshold while the engine 3 is automatically stopped (idling stop state), the CPU 11c of the integrated control ECU 11 controls the EVP When it is determined that the current consumption of the vehicle 1 does not exceed the idling stop release threshold (release threshold based on current consumption) even if the pump 13a of the unit 13 is driven, the drive of the pump 13a is controlled. In this way, during the idling stop control, the current consumption of the vehicle 1 does not exceed the idling stop release threshold when the pump 13a for assisting the negative pressure in the constant pressure chamber of the brake booster 14 is driven. It is possible to prevent idling stop control from being canceled based on an increase in current consumption. This improves the continuity of the idling stop control, thereby improving the fuel efficiency of the vehicle 1.

Further, if the current consumption of the vehicle 1 does not exceed the idling stop release threshold (release threshold based on current consumption) even if the pump 13a of the EVP unit 13 is driven, the drive control of the pump 13a is performed. It is possible to prevent the idling stop control from being canceled when the negative pressure in the constant pressure chamber of the brake booster 14 falls below the idling stop cancellation threshold (a cancellation threshold based on a decrease in negative pressure). This improves the continuity of the idling stop control, thereby improving the fuel efficiency of the vehicle 1.

(Modified example)
Next, a modification of the above-described embodiment will be described with reference mainly to FIG. 2(b) (particularly the vehicle current consumption (ii) in FIG. 2(b)). Note that this example differs from the above-described embodiments in that the method for preventing the current consumption of the vehicle 1 from exceeding the idling stop release threshold is different. The differences will be mainly explained below.

During the idling stop control, the CPU 11c of the integrated control ECU 11 controls when the pressure in the constant pressure chamber of the brake booster 14 becomes higher than a predetermined threshold (normal drive threshold: EVP ON threshold in FIG. 2) (when the negative pressure in the constant pressure chamber (when the current consumption of the vehicle 1 decreases to the normal drive threshold), drive control of the pump 13a is performed within a range in which the current consumption of the vehicle 1 does not exceed the idling stop release threshold.

For example, the CPU 11c of the integrated control ECU 11 acquires the value of the current consumption of the vehicle 1 when the pressure in the constant pressure chamber of the brake booster 14 becomes higher than a predetermined threshold (normal drive threshold: EVP ON threshold in FIG. 2). , calculates the difference between the value and the idling stop release threshold (release threshold based on current consumption). Then, the CPU 11c of the integrated control ECU 11 controls the drive of the pump 13a so that the current consumption when driving the pump 13a falls within the range of the calculated difference. Specifically, when the pump 13a is driven by a motor, the current consumption when driving the pump 13a is adjusted by switching ON/OFF the voltage applied to the motor at a predetermined frequency.

For example, if a motor is used whose current consumption is 1A when the duty ratio of the voltage ON/OFF pulse is 100%, the current consumption of the vehicle 1 when the negative pressure in the constant pressure chamber reaches the normal drive threshold is used. Assume that the difference between the value and the idling stop release threshold (release threshold based on current consumption) is 0.5A. In this case, the CPU 11c of the integrated control ECU 11 controls the drive of the pump 13a so that the voltage applied to the motor of the pump 13a becomes smaller than the duty ratio=50%.

Note that although both a brushless motor and a brushed motor can be used as the motor used to drive the pump 13a, it is preferable to use a brushless motor because the duty ratio of the applied voltage can be easily adjusted.

Next, the idling stop control of this embodiment will be described with reference to FIG. 2(b) (particularly the vehicle current consumption (ii) in FIG. 2(b)).

(If the engine automatically stops after stopping + the brake is pressed again while the engine is stopped: this example)
As shown in FIG. 2(b), in this embodiment, in the process of automatically stopping the engine 3, the driver first switches his/her foot from the accelerator pedal to the brake pedal 19 (the operation of the brake pedal 19 is turned on), thereby causing the vehicle to stop automatically. 1 decelerates (time T11). As a result, the negative pressure in the constant pressure chamber of the brake booster 14 decreases, but it is assumed that it does not decrease to the normal drive threshold for normal drive of the pump 13a of the EVP unit 13. Therefore, drive control of the pump 13a of the EVP unit 13 is not performed at time T11.

By continuing to press the brake pedal 19, the vehicle 1 stops at time T12, and when the engine 3 stop condition is satisfied at time T13, automatic stop control (idling stop control) of the engine 3 is performed. Accordingly, the current consumption of the vehicle 1 is reduced. Next, assume that the brake pedal 19 is pressed again at time T14 during engine stop control (during idling stop). It is assumed that, along with this, the negative pressure in the constant pressure chamber of the brake booster 14 decreases, and at time T15, it decreases to a normal drive threshold value at which drive control of the pump 13a of the EVP unit 13 is performed.

At this time, the CPU 11c of the integrated control ECU 11 calculates the idling stop release threshold (the vehicle 1's The differential current value until reaching the cancellation threshold (based on the current consumption) is calculated. Then, the CPU 11c of the integrated control ECU 11 adjusts the duty ratio of ON/OFF of the voltage applied to the motor so that the current consumption required for driving the pump 13a falls within the range of the calculated differential current value. The drive control is performed.

In this way, the negative pressure in the constant pressure chamber of the brake booster 14 increases by driving the pump 13a, so that the negative pressure does not fall below the idling stop release threshold (release threshold based on negative pressure), and the constant pressure chamber increases. Cancellation of idling stop control due to a decrease in negative pressure is avoided.

In addition, although the current consumption of the vehicle 1 increases due to the drive of the pump 13a, it does not exceed the idling stop cancellation threshold (a cancellation threshold based on current consumption), so that the idling stop control may not be canceled due to an increase in the current consumption of the vehicle 1. Avoided.

The drive control of the pump 13a of the EVP unit 13 is stopped when the negative pressure in the constant pressure chamber of the brake booster 14 recovers to a predetermined threshold value (time T16), and the current consumption of the vehicle is accordingly reduced.

As described above, by controlling the current consumption of the vehicle 1 using the method of this example, the same effects as in the above-described embodiment can be obtained.

Note that the present invention is not limited to the embodiments described above, and various modifications other than those described above can be made without departing from the spirit of the invention. For example, in the embodiments described above, various changes can be made. Although the processing is performed by one ECU (integrated control ECU 11), for example, the EFI control section, idling stop control section, CVT control section, ABS/VSC control section, and EVP control section may be configured with separate ECUs. good. In this case, for example, each ECU may exchange necessary information with each other via a communication bus such as CAN.

Further, the above-described embodiments can be applied not only to gasoline cars but also to electric cars, hybrid cars, and self-driving cars.

The present invention also provides a vehicle equipped with a control means that stops a running engine when a predetermined automatic engine stop condition is met, and automatically restarts a stopped engine when a predetermined engine restart condition is met. It can be applied to

1 Idling stop vehicle 11 Integrated control ECU (negative pressure auxiliary means)
14 Brake booster (brake auxiliary means)
13 EVP unit (negative pressure auxiliary means)
13a pump

Claims (4)

In a vehicle control device that stops a running engine when a predetermined automatic engine stop condition is met, and automatically restarts a stopped engine when a predetermined engine restart condition is met,
A brake assisting means that uses engine negative pressure to assist the brakes;
negative pressure auxiliary means that supplies auxiliary negative pressure to the brake auxiliary means by controlling the drive of a pump;
Equipped with
The predetermined engine restart condition includes that the current consumption of the vehicle, including the current required to drive the pump, exceeds a predetermined threshold;
For a vehicle, the negative pressure auxiliary means drives the pump within a range that does not exceed the predetermined threshold when supplying auxiliary negative pressure to the brake auxiliary means when the engine is automatically stopped. Control device. The vehicle control device according to claim 1, wherein the pump is an electric negative pressure pump driven by a motor. 3. The negative pressure auxiliary means drives the pump when it is determined that the current consumption of the vehicle does not exceed the predetermined threshold even if the pump is driven. control device for vehicles. When the negative pressure auxiliary means supplies auxiliary negative pressure to the brake auxiliary means during automatic stop of the engine, the current consumption of the vehicle when driving the pump does not exceed the predetermined threshold. 3. The vehicle control device according to claim 2, wherein the on-off cycle of the voltage applied to the pump is adjusted so that the voltage applied to the pump is turned on and off.

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