JP2015025385A - Control device for idle stop vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for an idle stop vehicle capable of improving fuel economy by executing idle stop control, while securing controllability of ABS control.SOLUTION: A control device 2 for an idle stop vehicle 1 includes: an ABS control unit 14 for performing automatic brake control for preventing slide of the idle stop vehicle 1 caused by lock of wheels; an idle stop control unit 12 for automatically stopping an engine 4 before the idle stop vehicle 1 stops by the establishment of a predetermined engine stop condition including the situation in which the idle stop vehicle 1 comes to a predetermined vehicle speed or less; and a voltage control unit 16 for supplying a backup voltage to the ABS control unit 14. The voltage control unit 16 starts supplying the backup voltage to the ABS control unit 14 when the idle stop vehicle 1 decelerates to a preset vehicle speed which is preset to be a value larger than the predetermined vehicle speed.

Description

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

  Conventionally, a so-called idle stop vehicle starts an engine by an IG (ignition) on operation, and then automatically stops the engine by satisfying a predetermined engine stop condition until the engine stops by an IG off operation. When the engine restart condition is satisfied, the engine is automatically restarted repeatedly (idle stop control). For the purpose of improving fuel efficiency, for example, such an idle stop vehicle automatically stops the engine while the vehicle is stopped, but in recent years, the engine is not only stopped while the vehicle is stopped, but also from the deceleration stage of the vehicle before stopping. Is automatically stopped to further improve fuel efficiency.

  As described above, in the system that executes the idle stop control at the vehicle deceleration stage, the vehicle speed region in which the idle stop control is executed and the automatic brake control (so-called ABS (Antilocked Breaking) for preventing the vehicle from sliding due to the wheel lock). There is a case where the vehicle speed region in which (System) control) is executed overlaps. In such a case, for example, when the engine is automatically stopped by the idle stop control, the ABS control is executed. When the engine restart condition is satisfied and the engine is restarted during the execution of the AGB control, this restart is performed. There is a problem in that the battery voltage temporarily decreases with the start, and the ABS control is not normally executed.

  Therefore, conventionally, there has been proposed an idle stop vehicle control device that prohibits execution of idle stop control that automatically stops the engine during execution of ABS control and under circumstances where ABS control can be performed (see Patent Document 1). ).

JP 2011-226315 A (see paragraphs 0043-0053, FIG. 3, etc.)

  However, in the above-described control apparatus for the idle stop vehicle, although the controllability of the ABS control can be ensured, since the opportunity for executing the idle stop control is limited, the engine is automatically stopped at the deceleration stage of the vehicle and further fuel consumption is improved. There is a problem that the meaning of the idle stop control to improve is weakened.

  The present invention has been made in view of the above problems, and provides an idle stop vehicle control device capable of improving fuel efficiency by executing idle stop control while ensuring controllability of ABS control. Objective.

  In order to achieve the above object, an idle stop vehicle control device according to the present invention includes a brake control means for performing automatic brake control for preventing the vehicle from slipping due to wheel locking, and a predetermined predetermined vehicle. An idle stop control means for automatically stopping the engine before the vehicle stops due to establishment of a predetermined engine stop condition including a vehicle speed or less, and a supply means for supplying a backup voltage to the brake control means, The supply means starts supplying the backup voltage to the brake control means when the vehicle decelerates to a set vehicle speed set to a value larger than the predetermined vehicle speed in advance ( Claim 1).

  According to the first aspect of the invention, the idle stop control means automatically stops the engine before the vehicle stops due to the establishment of a predetermined engine stop condition including that the vehicle speed is equal to or lower than a predetermined vehicle speed. However, the supply means starts supplying the backup voltage to the brake control means when the vehicle decelerates to the set vehicle speed before the engine is automatically stopped by the idle stop control means. With this configuration, since the voltage necessary for the control of the brake control unit is secured by the backup voltage before the execution of the control by the idle stop control unit, for example, in the state where the control of the brake control unit is executed, Even if the battery voltage temporarily decreases due to the restart of the engine, the control by the brake control means can be executed normally.

  Further, by ensuring the voltage necessary for the control of the brake control means, the idle stop control can be performed during the execution of the control by the brake control means and in the situation where the control can be executed as in the conventional control device for the idle stop vehicle. There is no need to prohibit control by means. Therefore, the idle stop control means can execute the automatic engine stop control when the vehicle decelerates to a predetermined vehicle speed without being restricted by the execution of the control of the brake control means. The fuel consumption can be improved.

1 is a block diagram of a control device for an idle stop vehicle according to an embodiment of the present invention. FIG. It is operation | movement explanatory drawing of the control apparatus of the idle stop vehicle concerning a comparative example. It is operation | movement explanatory drawing of the control apparatus of the idle stop vehicle of FIG. It is a flowchart for operation | movement description of the control apparatus of the idle stop vehicle of FIG.

  A control device 2 for an idle stop vehicle 1 according to an embodiment of the present invention will be described with reference to FIG. FIG. 1A is a block diagram of the control device 2 of the idle stop vehicle 1.

(Constitution)
As shown in FIG. 1, an idle stop vehicle 1 (hereinafter sometimes referred to as a vehicle 1) is provided with a single lead battery 3 having a relatively small capacity of 12V as a power source in order to reduce weight, size, and the like. The negative terminal of the battery 3 is connected to the body of the idle stop vehicle 1.

  The engine 4 that is a drive source of the vehicle 1 has a transmission-side CVT 5, and a torque converter (including a lock-up clutch mechanism) 6 is interposed between the CVT 5 and the engine 4.

  The engine 3 is started by the starter 7, and the starter 7 is supplied with power from the lead battery 3 through the relay 8 to generate a driving force for starting the engine 4. In addition, the battery sensor 9 provided in the vicinity of the lead battery 3 between the positive terminal of the lead battery 3 and the relay 8 detects the temperature and current of the lead battery 3, and the rotational force of the engine 4 causes the belt 10 to rotate. The lead battery 3 is charged by the power generation output of the alternator 11 during traveling of the vehicle.

  Further, as shown in FIG. 1, the vehicle 1 is provided with an idle stop control unit 12 formed by an ECU for idle stop control, an engine control unit 13 formed by an ECU for engine control, and an ECU for ABS control. The ABS control unit 14, the CVT control unit 15 formed by the CVT (Continuously Variable Transmission) control ECU, and the voltage control unit 16 formed by the backup voltage control ECU supplied to the ABS control unit 14 (corresponding to the supply means of the present invention) The control units 12 to 16 are each formed by a microcomputer or the like, and exchange information via a communication bus 17 such as CAN.

  The ABS control unit 14 is provided with four wheel speed sensors 17 for detecting the wheel speeds of the four wheels of the vehicle 1 and a hydraulic pressure sensor 18 for detecting a master cylinder pressure of the brake mechanism and the like. Automatic brake control for preventing the vehicle 1 from sliding is executed. Briefly describing this brake control, the ABS control unit 14 calculates the slip ratio of each wheel from the wheel speed of each wheel detected by each wheel speed sensor 17, and maintains the slip ratio within a predetermined range. As described above, the master cylinder pressure, and hence the brake fluid pressure for each wheel, is controlled to be instantaneously switched, and the sliding of the vehicle 1 due to the locking of each wheel is prevented. Such a brake control function by the ABS control unit 14 corresponds to “brake control means” in the present invention. The ABS control unit 14 calculates the vehicle speed of the vehicle from the wheel speed of each wheel detected by the wheel speed sensor 17 and sends the vehicle speed information to the idle stop control unit 12 and the voltage control unit 16.

  The idle stop control unit 12 automatically stops the engine 4 before the vehicle 1 stops due to the establishment of a predetermined engine stop condition including that the vehicle 1 becomes a predetermined vehicle speed or less. The engine 4 is automatically restarted when the start condition is satisfied. Specifically, the idle stop control unit 12 determines that the vehicle speed of the vehicle 1 is equal to or lower than a predetermined speed (vehicle speed = 11 km / h in this embodiment), the master cylinder pressure is equal to or higher than a predetermined depression pressure value, and a stop lamp. When it is confirmed that a predetermined engine stop condition including that is lit, an engine stop command is output to the engine control unit 13 and the engine 4 is automatically stopped. Subsequently, when the idle stop control unit 12 confirms that a predetermined engine restart condition such as the driver removing his foot from the brake pedal is satisfied in the automatic stop state, an engine restart command is output to the engine control unit 13. Then, the stopped engine 4 is automatically started. Such an idle stop control function by the idle stop control unit 12 corresponds to the “idle stop control means” in the present invention.

  The idle stop operation of the idle stop vehicle 1 having such a configuration will be briefly described. When the driver gives an engine start command after turning on an IG (ignition) key (not shown), an IG ON signal Is input from the communication bus 17 to the idle stop control unit 12, and based on this input, the idle stop control unit 12 instantaneously energizes the relay 8 to turn on the power and supply the power of the lead battery 3 to the starter 7. The starter 7 is started, and the stopped engine 4 is started (initial start). Once the engine 4 is started and the lead battery 3 is once fully charged with the power generated by the alternator 11, the idle stop control unit 12 is then idle stopped until the engine 4 is stopped by turning off the IG key. Execute control.

  The idle stop control unit 12 includes information on the engine control unit 13 (engine information such as the engine speed and cooling water temperature), information on the current and temperature of the lead battery 3, and the brake control unit via the communication bus 17. 14, vehicle speed information of the vehicle 1, information such as master cylinder pressure by the hydraulic pressure sensor 18, ON / OFF information of the lock-up clutch of the CVT control unit 15, and the like are input.

  Based on this information, the idle stop control unit 12 during the idle stop control, the driver depresses the brake pedal in accordance with a traffic light red signal or the like, and the master cylinder pressure becomes equal to or higher than a predetermined depressing pressure, and the stop lamp lights up. If the vehicle 1 is decelerated to a predetermined vehicle speed or less even if the vehicle 1 is not stopped by confirming that a predetermined engine stop condition such as that the vehicle 1 is a predetermined speed or less is satisfied, the engine control unit 13 The engine control unit 13 automatically stops the engine 4 by, for example, reducing the fuel throttle.

  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, such as when the traffic signal changes to a green light, the idle stop control unit 12 performs a predetermined idle stop control. After confirming that the engine restart condition has been established, the idle stop control unit 12 energizes the relay 8 instantaneously to turn it on, and feeds the power of the lead battery 3 to the starter 7 to start the starter 7 and stop the engine. 4 is automatically restarted. Thereafter, automatic stop of the engine 4 based on establishment of a predetermined engine stop condition during deceleration and automatic restart of the engine 4 based on establishment of a predetermined engine restart condition are alternately performed.

  The voltage control unit 16 is provided with a booster circuit for maintaining the voltage supplied from the lead battery 3 at a voltage (for example, 12 to 15 V) necessary for the control of the ABS control unit 14, and a predetermined voltage supply start condition As a result, the backup voltage is supplied to the ABS control unit 14. Specifically, the voltage control unit 16 acquires information regarding the vehicle speed of the vehicle 1 calculated by the ABS control unit 14 via the communication bus 17, and the vehicle 1 is set to a value larger in advance than the predetermined vehicle speed. When the vehicle is decelerated to the set vehicle speed (12 km / h in this embodiment), supply of the backup voltage to the ABS control unit 14 is started. As described above, when the vehicle 1 is decelerated to the set vehicle speed that is a timing before the predetermined vehicle speed at which the idle stop control by the idle stop control unit 12 is executed, the voltage control unit 16 backs up to the ABS control unit 14. By supplying the voltage, a voltage necessary for the control with respect to the ABS control unit 14 during the idle stop control is secured. Such a voltage supply control function by the voltage controller 16 corresponds to the “supply means” of the present invention. The set vehicle speed in the voltage supply start condition described above is an example, and can be appropriately changed as long as it is equal to or higher than the predetermined vehicle speed.

  Next, backup voltage supply start timing to the ABS control unit 14 by the voltage control unit 16 will be described with reference to FIG. 2 and FIG. 3 in comparison with the comparative example. 2 is a diagram for explaining the start timing of supply of the backup voltage of the control device for the idle stop vehicle according to the comparative example, and FIG. 3 is the supply of the backup voltage of the control device 2 for the idle stop vehicle 1 according to the present embodiment. It is a figure for demonstrating start timing. 2 (a) and 3 (a) respectively show the relationship between the vehicle speed and time of the vehicle 1, and FIGS. 2 (b) and 3 (b) show the start of engine automatic stop control by the idle stop control unit 12, respectively. 2 (c) and FIG. 3 (c) are the ON / OFF switching timings of lockup (L / U), respectively, and FIG. 2 (d) and FIG. Indicates timing.

  First, as an engine stop condition of the idle stop control by the idle stop control unit 12, in addition to the above, the lock-up is in an OFF state. This is because if the engine 4 is automatically stopped while the lockup clutch of the torque converter 6 is in the ON state, an engine stop (so-called engine stall) occurs. Further, in this embodiment, the lockup is turned off when the vehicle 1 is decelerated to 11 km / h. Then, from the viewpoint of improving fuel efficiency, the engine automatic stop control by the idle stop control unit 12 is Ideally it will be started when the lockup is turned off. Therefore, as in the comparative example shown in FIG. 2, for example, after the voltage control unit 16 acquires the lock-up OFF information from the CVT control unit 15 via the communication bus 17, the backup voltage to the ABS control unit 14 is obtained. When the supply is started, the fact that the supply start control is completed is outputted to the idle stop control unit 12, and when the idle stop control unit 12 receiving the output starts the automatic engine stop control, it is shown in FIG. Thus, a time lag occurs between the timing when the lock-up is turned off and the start timing of the engine automatic stop control by the idle stop control unit 12 (for example, vehicle speed = 9 km / h).

  Therefore, in this embodiment, the idle stop control unit 12 confirms that the vehicle speed, which is the ideal engine automatic stop control start timing, is 11 km / h (vehicle speed at which the lockup is turned off) or less from the viewpoint of improving fuel efficiency. The predetermined vehicle speed of the engine stop condition is determined, and the timing at which the voltage control unit 16 starts supplying the backup voltage to the ABS control unit 16 is set to a preset vehicle speed (the vehicle 1 is set to a value larger than the predetermined vehicle speed) In this embodiment, it is set when decelerating to 12 km / h). With this configuration, the control device 2 for the idle stop vehicle 1 according to this embodiment secures controllability of automatic brake control by the ABS control unit 16 by supplying a stable voltage to the ABS control unit 16. On the other hand, the engine automatic stop control by the idle stop control unit 12 is started at an early stage so that the fuel efficiency of the vehicle 1 can be further improved.

  In this case, the voltage control unit 16 decelerates the vehicle 1 to 12 km / h based on the vehicle speed information acquired from the ABS control unit 14 via the communication bus 17 before acquiring the lock-up OFF information from the CVT control unit 15. Then, supply of the backup voltage to the ABS control unit 14 is started (see FIG. 3D), and this is output to the idle stop control unit 12 after completion of the supply start control. When the idle stop control unit 12 acquires the output indicating that the supply start control is completed before acquiring the lockup OFF information, as shown in FIG. 3B, the CVT control unit 15 The engine automatic stop control is started at substantially the same timing as when the lockup OFF information is acquired from the communication bus 17.

  Next, idle stop processing (engine automatic stop control) by the control device 2 of the idle stop vehicle 1 according to this embodiment will be described with reference to FIG. FIG. 4 is a flowchart of the idle stop process.

  First, in step S1, the voltage control unit 16 determines whether or not the vehicle 1 has decelerated to the set vehicle speed (vehicle speed = 12 km / h) based on the vehicle speed information of the vehicle 1 from the ABS control unit 14, and the vehicle When 1 is decelerated to the set vehicle speed, the booster circuit is driven to start supplying the backup voltage to the ABS control unit 14 (step S2). When step S1 is NO, step S1 is repeated until the vehicle 1 decelerates to the set vehicle speed. Note that, after the backup voltage supply start control is completed, the voltage control unit 16 outputs a signal to that effect to the idle stop control unit 12.

  Next, the idle stop control unit 12 that has acquired the signal indicating that the start control of the backup voltage supply output from the voltage control unit 16 has been completed, performs lockup based on the lockup ON / OFF information from the CVT control unit 15. It is determined whether or not is in an OFF state (step S3). When the idle stop control unit 12 determines that the lockup is in the OFF state, the vehicle 1 decelerates to a predetermined vehicle speed (11 km / h) based on the vehicle speed information of the vehicle 1 from the ABS control unit 14. It is judged whether it is (step S4). If NO in step S3 (lockup is in an ON state), the idle stop control unit 12 repeats the processes in steps S1 to S3 until the lockup is in an OFF state.

  Next, in step S4, when the idle stop control unit 12 determines that the vehicle 1 is decelerated to a predetermined vehicle speed, it determines that a predetermined engine stop condition is satisfied, and executes automatic stop control of the engine 4. (Step S5), the idle stop process is terminated. If NO in step S4, steps S1 to 4 are repeated until the vehicle 1 decelerates to a predetermined vehicle speed.

  Therefore, according to the above-described embodiment, the idle stop control unit 12 is configured so that the vehicle 1 stops before the vehicle 1 stops due to the establishment of a predetermined engine stop condition including that the vehicle speed of the vehicle 1 is equal to or lower than a predetermined vehicle speed. Although the engine is automatically stopped, the voltage control unit 16 starts supplying the backup voltage to the ABS control unit 14 when the vehicle 1 decelerates to the set vehicle speed before the engine automatic stop control by the idle stop control unit 12. To do. If comprised in this way, since the voltage required for control of the ABS control part 14 is ensured by the backup voltage from the start of control by the idle stop control part 12, for example, control of the ABS control part 14 was performed. In this state, even if the battery voltage decreases due to the restart of the engine 4, the brake control by the ABS control unit 14 can be normally executed.

  Further, by securing a voltage necessary for the control of the ABS control unit 14, the idle control can be performed during the execution of the control by the ABS control unit 14 and in a situation where the control can be executed, as in a conventional control device for an idle stop vehicle. It is not necessary to prohibit the engine automatic stop control by the stop control unit 12. Therefore, the idle stop control unit 12 can execute the automatic stop control of the engine 4 when the vehicle 1 is decelerated to a predetermined vehicle speed without being restricted by whether or not the control of the ABS control unit 14 is executed. Thus, the fuel consumption of the idle stop vehicle 1 can be improved.

  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 thereof. For example, in the above-described embodiment, idle In the control device 2 of the stop vehicle 1, the case where the idle stop control unit 12 and the voltage control unit 16 are separately provided has been described. For example, the idle stop control unit 12 is further provided with the function of the voltage control unit 16. It doesn't matter.

  Further, in the above-described embodiment, the wheel speed sensor 17 is provided in the ABS control unit 14; however, a configuration in which these are provided individually may be employed.

1 ... Idle stop car (vehicle)
2 ... Control device 4 ... Engine 12 ... Idle stop control section (idle stop control means)
14 ... ABS control section (brake control means)
16 ... Voltage control unit (supply means)

Claims (1)

Brake control means for performing automatic brake control to prevent the vehicle from sliding due to wheel locking;
Idle stop control means for automatically stopping the engine before the vehicle stops due to establishment of a predetermined engine stop condition including that the vehicle has a predetermined vehicle speed or less.
Supply means for supplying a backup voltage to the brake control means,
The supply means starts the supply of the backup voltage to the brake control means when the vehicle decelerates to a set vehicle speed set to a value larger than the predetermined vehicle speed in advance. Stop car control device.

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