JP2014173454A - Control device of idle stop vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a battery by suppressing the consumption of a battery, and to improve fuel economy by idle stop control, in an idle stop vehicle having a following traveling function.SOLUTION: At following control, a threshold for determining the non-establishment of an engine stop condition at following traveling control by an ACC control part 15 is changed and set higher by an idle stop control part 11. Therefore, when a power accumulation amount (remaining amount) of a battery 2 detected by the idle stop control part 11 is a high threshold which is newly changed and set at the following traveling control by the ACC control part 15, since there is a leeway in the power accumulation amount of the battery 2, a vehicle is controlled to an idle stop condition when an engine stop condition is established, and on the other hand, when the power accumulation amount of the battery 2 detected by the idle stop control part 11 is smaller than the high threshold which is newly changed and set, the non-establishment is determined even if the engine stop condition is established by the idle stop control part 11, the vehicle is not controlled to the idle stop state, and only the following traveling control becomes executable.

Description

  The present invention relates to a control device for an idle stop vehicle that stops an engine when a predetermined engine stop condition is satisfied, enters an idle stop state, and restarts the engine when a predetermined engine restart condition is satisfied in the idle stop state.

  Conventionally, a so-called idle stop vehicle starts an engine by an IG (ignition) on operation, and thereafter executes an idle stop control until the engine is stopped by an IG off operation. The engine is automatically stopped and the engine is automatically restarted when a predetermined engine restart condition is satisfied.

  In recent years, vehicles equipped with this kind of idle stop control function are also provided with a follow-up running control function that follows a preceding vehicle by acceleration and deceleration while maintaining a predetermined inter-vehicle distance with respect to the preceding vehicle. (See Patent Document 1).

JP 2004-245099 A (see paragraphs 0007, 0009 to 0013)

  By the way, in the case of a vehicle having a follow-up running function and an idle stop function as described in Patent Document 1, the automatic brake means is driven for deceleration in follow-up running control. Since it is comparatively large, if the engine is idle-stopped while traveling, the engine will stop and power generation will not be possible, so there is a possibility that the battery cannot be charged.

  Therefore, if the automatic brake for follow-up control is activated during idle stop, the battery capacity (charged amount) tends to decrease, and the battery capacity may inadvertently drop to a level where the battery deteriorates, reducing battery consumption. There is a problem that it cannot be suppressed.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an idle stop vehicle having a follow-up running function that protects the battery by suppressing battery consumption, and at the same time improves fuel efficiency through idle stop control.

  In order to achieve the above-described object, the control device for an idle stop vehicle according to the present invention stops the engine in accordance with establishment of a predetermined engine stop condition to enter an idle stop state, and the predetermined engine restart condition is satisfied in the idle stop state. In a control device for an idle stop vehicle that restarts the engine when established, a generator that generates electric power by the driving force of the engine to charge the power storage device, a detection unit that detects a power storage amount of the power storage device, When the engine stop condition is satisfied, the engine is automatically stopped to place the vehicle in an idle stop state. Even if the engine stop condition is satisfied during traveling, the amount of power stored in the power storage device by the detection unit is determined in advance. When the engine stop condition is less than the predetermined threshold value, it is determined that the engine stop condition is not satisfied, and the idle stop is performed. Idle stop control means that does not enter the state, follow-up running control means that performs follow-up running control that follows the preceding vehicle by acceleration and deceleration with respect to the preceding vehicle, and the following using the electrical energy stored in the power storage device Automatic braking means for executing deceleration by the travel control means, wherein the idle stop control means changes and sets the threshold value high during the follow-up travel control (claim 1).

  According to the first aspect of the present invention, if the engine stop condition is satisfied during traveling by the idle stop control means, the engine is automatically stopped and the vehicle is controlled to the idle stop state, and the engine stop condition is satisfied during traveling. However, if the power storage amount of the power storage device detected by the detection means is less than a predetermined threshold value, it is determined that the engine stop condition is not satisfied and the engine is not controlled to the idle stop state, and the tracking travel control means In the follow-up running control, a threshold value serving as a reference for determining that the engine stop condition is not satisfied is changed and set high.

  Therefore, during the follow-up running control, the idle stop control means changes the threshold of the charged amount, which is a criterion for judging that the engine stop condition is not met even if the engine stop condition is met, Even if the power of the power storage device is consumed by the operation of the automatic brake means when the actual power storage amount of the power storage device is equal to or higher than the newly changed high threshold and the engine stop condition is satisfied and the engine is in the idle stop state. Therefore, the amount of stored electricity does not drop below the level at which the power storage device deteriorates, and deterioration of the power storage device can be prevented in advance.

  Furthermore, if the actual power storage amount of the power storage device is less than the high threshold during the follow-up running control, the idle stop control means determines that the engine stop condition is satisfied and is not controlled to the idle stop state, Charging of the power storage device can be continued, and it becomes possible to protect the power storage device by preventing a reduction in the amount of power stored in the power storage device. The fuel consumption can be improved by the idle stop control at the same time as suppressing the battery.

It is a block diagram of one embodiment of a control device of an idle stop car of the present invention.

  Next, an embodiment of the present invention will be described with reference to FIG.

  As shown in FIG. 1, the idle stop vehicle 1 has one lead battery (corresponding to the power storage device in the present invention) 2 having a relatively small capacity of 12 V as a power source in order to reduce weight, size, and the like. The negative terminal of the battery 2 is connected to the vehicle body of the idle stop vehicle 1.

  The engine 3 that is the drive source of the idle stop vehicle 1 has a transmission-side CVT 4, and a torque converter (including a lock-up clutch mechanism) 5 is interposed between the CVT 4 and the engine 3.

  The engine 3 is started by a starter 6. The starter 6 is supplied with power from the battery 2 via a relay 7 and generates a driving force for starting the engine 3. Further, a battery sensor 8 provided close to the battery 2 between the positive terminal of the battery 2 and the relay 7 outputs a temperature / current detection signal of the battery 2 to an idle stop control unit described later, and the engine 3 Is transmitted to the alternator 9, which is a generator, via the belt 10, and the battery 2 is charged by the power generation output of the alternator 9 while the vehicle is running.

  Further, as shown in FIG. 1, the idle stop vehicle 1 is provided with an idle stop control unit (corresponding to the idle stop control means in the present invention) 11 formed by the idle stop control ECU. The engine control unit 12 to be formed, the brake control unit 13 formed by a vehicle stability control (VSC) ECU for skid control, the CVT control unit 14 formed by an ECU for CVT (Continuously Variable Transmission) control, and the ACC in the full vehicle speed range (Adaptive Cruise Control) The ACC control part 15 which ECU of control forms is provided, and each of these control parts 11-15 are each formed by the microcomputer etc., and CAN etc. And exchanges of information via the signal bus 16.

  Then, when the temperature and current detection signals of the battery 2 from the battery sensor 8 are input, the idle stop control unit 11 detects the temperature, current, and charged amount (remaining amount) of the battery 2 based on these detection signals. To do. Such a function of detecting the charged amount of the battery 2 by the idle stop control unit 11 corresponds to the detecting means in the present invention.

  Further, when it is confirmed that a predetermined engine stop condition (for example, a condition that the stop lamp is lit and the vehicle speed is equal to or lower than the predetermined vehicle speed) is satisfied, the idle stop control unit 11 does not stop traveling completely. When the vehicle speed falls below a predetermined vehicle speed (for example, 7 km / h or less), an engine stop command is output to the engine control unit 12 and the engine 3 is automatically stopped. Subsequently, when the driver removes his / her foot from the brake pedal in the automatic stop state, it is confirmed by the idle stop control unit 11 that a predetermined engine restart condition is satisfied, and the stopped engine 3 is automatically restarted. The

  Further, as shown in FIG. 1, a vehicle speed sensor 18 is provided that detects the vehicle speed and provides the vehicle speed information to the brake control unit 13. The hydraulic pressure sensor provides the brake control unit 13 with detection information of the master cylinder pressure of the brake mechanism. 19, a steering angle sensor 20 for detecting the steering angle of the steering is provided, and a display unit 21 formed by a combination meter is provided on the dashboard. Various display data received via the communication bus 16 are stored in the dashboard. It is displayed on the display unit 21.

  Further, the ACC control unit 15 corresponds to the following traveling control means in the present invention, takes in a detection signal of the laser radar 22 that measures the distance from the preceding vehicle ahead of the host vehicle at predetermined time intervals, and controls the brake control unit 13 and the communication bus. 16, the vehicle speed information of the host vehicle detected by the vehicle speed sensor 18 is taken in, and based on the inter-vehicle distance from the preceding vehicle and the host vehicle speed, it is detected whether or not there is a possibility of collision with the preceding vehicle. When the main switch 23 is turned on, the ACC control unit 15 enters a standby state. When the ACC set switch 24 is turned on in the standby state, acceleration and deceleration are controlled by the engine control unit 12 and the brake control unit 13. Follows the preceding vehicle while maintaining a predetermined distance that is not likely to collide with the vehicle speed at that time. Performing follow-up running control in full speed range that. Even if the ACC main switch 23 is in the standby state, the follow-up running control is not executed if the ACC set switch 24 is off, and the ACC control unit 15 does not operate if the ACC main switch 23 is off.

  By the way, the brake control unit 13 corresponds to the automatic brake means in the present invention, and a brake fluid pressure control valve (for example, a solenoid valve) downstream of the master cylinder (not shown) at the time of a sudden brake operation by a driver or a brake operation on a low friction road. ) And brake control for controlling the braking force of each wheel to prevent sliding due to wheel locking.

  When the ACC control unit 15 detects that there is a possibility of collision with an obstacle such as a vehicle ahead, the ACC control unit 15 outputs an automatic brake command to the brake control unit 13, The brake control unit 13 controls the brake hydraulic pressure control valve downstream of the master cylinder so as to perform deceleration to avoid collision with an obstacle, and automatically applies the brake regardless of the operation of the brake pedal by the driver. Automatic brake operation control is executed. At this time, when the brake fluid pressure control valve is controlled, the valve opening / closing degree is controlled by the electric power of the battery 2, and the electric energy of the battery 2 is used.

  An idle stop operation of the idle stop vehicle 1 having such a configuration will be briefly described. When a driver turns on an IG key (not shown) to instruct an engine start, an IG on signal is transmitted to a communication bus, for example. 16 is input to the idle stop control unit 11, and based on this input, the idle stop control unit 11 energizes the relay 7 instantaneously to turn it on, and feeds the power of the lead battery 2 to the starter 6 to start the starter 6. Then, the stopped engine 3 is started (initial start). Once the engine 3 is started and the lead battery 2 is once fully charged with the power generated by the alternator 9, the idle stop control unit 11 is then idle stopped until the engine 3 is stopped by turning off the IG key. Execute control.

  The idle stop control unit 11 includes information on the engine control unit 12 (engine information such as the engine speed and cooling water temperature), information on the current and temperature of the battery 2, and the brake control unit 13 via the communication bus 16. Information on the vehicle speed detected by the vehicle speed sensor 18 via the vehicle, information on the master cylinder pressure by the hydraulic pressure sensor 19, lock-up clutch information on the CVT control unit 14, information on switches in various parts of the vehicle such as a stop lamp switch and a courtesy switch (not shown), etc. Is entered.

  Based on this information, the idle stop control unit 11 during the idle stop control confirms that the driver depresses the brake pedal according to a red signal of the traffic signal and the like, and that the master cylinder pressure is equal to or higher than a predetermined depression pressure. When detected, by confirming that a predetermined engine stop condition for idle stop control (for example, a condition that the stop lamp is lit and the vehicle speed is equal to or less than the predetermined vehicle speed) is satisfied, the predetermined vehicle speed If the speed falls below (for example, 7 km / h or less), an engine stop command is output to the engine control unit 12, and the engine control unit 12 throttles the fuel throttle to automatically stop the engine 3.

  Next, when it is detected that the driver has lifted his / her foot from the brake pedal and the master cylinder pressure has dropped to a predetermined release pressure, for example, the traffic signal changes to a green light, the idle stop control unit 11 performs a predetermined idle stop control. After confirming that the engine restart condition is satisfied, the idle stop control unit 11 energizes the relay 7 instantaneously to turn it on, supplies the power of the battery 2 to the starter 6, starts the starter 6, and stops the engine 3. Will automatically restart. Thereafter, automatic stop of the engine 3 based on establishment of a predetermined engine stop condition during deceleration and automatic restart of the engine 3 based on establishment of a predetermined engine restart condition are alternately performed.

  At this time, when the engine 3 is restarted, the engine speed information reaches the speed indicating complete explosion, the brake force returns to the original state changing according to the master cylinder pressure, and the accelerator pedal is not depressed. This is a so-called idling state, and the engine 3 and the torque converter 5 generate a creep force that allows the idle stop vehicle 1 to start even in this idling state.

  By the way, when the engine stop condition is satisfied during traveling and the engine 3 is automatically stopped and controlled to the idle stop state by the idle stop control unit 11 as described above, the idle stop is based on the detection signal from the battery sensor 8. If the charged amount (remaining amount) of the battery 2 detected by the stop control unit 11 is less than a predetermined threshold value, it is determined that this is not established even if the engine stop condition is satisfied, and the idle stop control unit 11 is not executed. Thereby, charging of the battery 2 can be continued, and a decrease in the amount of electricity stored in the battery 2 is prevented.

  Further, when the ACC main switch 23 is on and the ACC set switch 24 is in a so-called standby state, or when the ACC main switch 23 is on and the ACC set switch 24 is on, the following tracking control is being executed. During the control, the idle stop control unit 11 changes and sets a high threshold value for determining that the engine stop condition in the follow-up traveling control by the ACC control unit 15 is not satisfied. Here, the high threshold value to be changed may be determined by experimentally examining the degree of consumption of the battery 2 and the like.

  Therefore, during the follow-up running control by the ACC control unit 15, if the storage amount (remaining amount) of the battery 2 detected by the idle stop control unit 11 is equal to or higher than the newly changed high threshold, the storage of the battery 2 is performed. Since there is a surplus in the amount, the engine is controlled in the idle stop state if the engine stop condition is satisfied, while the charged amount of the battery 2 detected by the idle stop control unit 11 is less than the newly set high threshold. For example, even if the engine stop condition is satisfied, the idle stop control unit 11 determines that the engine stop condition is not satisfied, and it is not controlled to the idle stop state, and only the follow-up traveling control can be executed.

  Therefore, according to the above-described embodiment, the idle stop control unit 11 changes the threshold value of the charged amount of the battery 2 that determines that the engine stop condition is not satisfied even if the engine stop condition is satisfied. When the stored amount of the battery 2 detected at the time is equal to or higher than the newly changed high threshold value and the engine stop condition is satisfied and the engine enters the idle stop state as usual, the brake control unit 13 is activated. Even when the electric power of the battery 2 is consumed, the stored amount (remaining amount) does not decrease to a level below which the battery 2 deteriorates, and the deterioration of the battery 2 can be prevented in advance.

  Further, if the stored amount of the battery 2 detected during the follow-up running control is less than the newly changed high threshold, the idle stop control unit 11 determines that this is not established even if the engine stop condition is established. Therefore, it is not controlled to the idle stop state, it is possible to continue charging the battery 2, and it is possible to protect the battery 2 by preventing the stored amount of the battery 2 from decreasing.

  As described above, according to the present embodiment, in the idle stop vehicle 1 having the following traveling function, the consumption of the battery 2 can be suppressed to protect the battery 2, and at the same time, the fuel efficiency can be improved by the idle stop control.

  The present invention is not limited to the above-described embodiment, and various modifications other than those described above can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, an idle stop vehicle equipped with only the engine 3 has been described, but the present invention can also be applied to a hybrid vehicle using both an engine and a motor.

1 ... Idle stop car 3 ... Engine 9 ... Alternator (generator)
11: Idle stop control section (detection means, idle stop control means)
13 ... Brake control means (automatic brake means)
15 ... ACC control unit (following travel control means)

Claims (1)

In a control device for an idle stop vehicle that stops the engine by establishment of a predetermined engine stop condition and enters an idle stop state, and restarts the engine by establishment of a predetermined engine restart condition in the idle stop state.
A generator for generating electricity by the driving force of the engine and charging the power storage device;
Detecting means for detecting the amount of electricity stored in the electricity storage device;
When the engine stop condition is satisfied during traveling, the engine is automatically stopped to place the vehicle in an idle stop state. Even if the engine stop condition is satisfied during traveling, the amount of power stored in the power storage device by the detection means Is less than a predetermined threshold value, an idle stop control means that determines that the engine stop condition is not satisfied and does not enter the idle stop state;
Follow-up running control means for performing follow-up running control for running following the preceding vehicle by acceleration and deceleration with respect to the preceding vehicle;
Automatic braking means for performing deceleration by the following traveling control means using the electrical energy stored in the power storage device,
The idle stop control means is configured to change and set the threshold value to be higher during the follow-up running control.

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