JP2020084881A - vehicle - Google Patents

Abstract

To restrain deterioration of accuracy of a down-hill assist control or a crawl control.SOLUTION: A vehicle has a control device for automatically stopping an engine when an automatic stopping condition is satisfied, and automatically starting the engine together with cranking of the engine due to a starter when an automatic starting condition is satisfied during the engine is automatically stopped. The control device limits the automatic stop of the engine at the time of actuation allowance or actuation of the down-hill assist control or the crawl control.SELECTED DRAWING: Figure 2

Description

The present invention relates to a vehicle.

Conventionally, this type of vehicle includes a disc brake unit that applies braking force to wheels, a driver turns on a DAC (Downhill Assist Control) switch, and a shift sensor detects that the vehicle is in a predetermined shift position. In this case, it is proposed that the DAC control is performed to control the braking force applied to the wheels by the brake unit so that the vehicle speed does not become higher than a predetermined value even if the brake pedal is not operated (for example, Patent Document 1). 1).

JP, 2008-174001, A

In the above vehicle, when the engine is automatically stopped and automatically started when the DAC switch is turned on, the voltage of the battery is lowered due to cranking of the engine by the starter for automatically starting the engine, and the disc brake after starting is started. It may not be possible to sufficiently secure the electric power required for the hydraulic control of the unit, and the accuracy of the DAC control may deteriorate.

The vehicle of the present invention mainly aims to suppress a decrease in accuracy of downhill assist control control or crawl control.

The vehicle of the present invention adopts the following means in order to achieve the above-mentioned main object.

The vehicle of the present invention is
An engine for driving,
A starter for cranking the engine,
A braking force applying device capable of applying a braking force to wheels,
A power storage device connected to the engine, the starter, and the braking force applying device via a power line;
The engine, the starter, and the braking force application device are controlled, and when the automatic stop condition is satisfied, the engine is automatically stopped, and when the automatic start condition is satisfied during the automatic stop of the engine, the starter controls the engine. A control device for automatically starting the engine with cranking,
A vehicle comprising:
The control device limits the automatic stop of the engine at the time of permitting or operating the downhill assist control control or the crawl control,
That is the summary.

In the vehicle of the present invention, the engine is automatically stopped when the automatic stop condition is satisfied, and the engine is automatically started with cranking of the engine by the starter when the automatic start condition is satisfied during the automatic stop of the engine. Then, when the downhill assist control control or the crawl control operation is permitted or activated, the automatic stop of the engine is limited. Here, the "downhill assist control control" is a control for controlling the braking force application device so that the vehicle speed is maintained at a predetermined vehicle speed or less even if the brake operation is not performed on the downhill road, and the "crawl control" is The control is for controlling the engine and the braking force application device so that the vehicle speed is maintained at a predetermined vehicle speed even if the accelerator operation and the brake operation are not performed. By limiting the automatic stop of the engine when permitting or operating the downhill assist control control or crawl control, it is possible to avoid the voltage drop of the power storage device that accompanies the automatic start of the engine at the start, and the downhill assist control after the start. It is possible to prevent the electric power required for control or crawl control from being insufficiently secured. As a result, it is possible to prevent the accuracy of the downhill assist control control or the crawl control from decreasing.

In such a vehicle of the present invention, the control device prohibits automatic stop of the engine (continues operation) during operation of the engine at the time of operation permission or operation of downhill assist control control or crawl control. During the automatic stop of the engine, the engine may be automatically started immediately by the motoring of the engine by the starter.

It is a block diagram which shows the outline of a structure of the motor vehicle 20 as one Example of this invention. 6 is a flowchart showing an example of a processing routine executed by the main ECU 50. FIG. 6 is an explanatory diagram showing an example of the state of the engine 22, the brake pedal position BP, the hydraulic pressures of the brake wheel cylinders 46 a to 46 d, the vehicle speed V, and the voltage Vb of the battery 36 when the DAC permission switch 69 is on.

Next, modes for carrying out the present invention will be described using examples.

FIG. 1 is a configuration diagram showing an outline of a configuration of an automobile 20 as an embodiment of the present invention. As shown in the figure, the automobile 20 of the embodiment has an engine 22, a transmission 24, a starter 30, an alternator 32, a battery (electric storage device) 36, a hydraulic brake device (braking force applying device) 40, a main body. An electronic control unit (hereinafter referred to as “main ECU”) 50 is provided.

The engine 22 is configured as an internal combustion engine that outputs power using gasoline, light oil, or the like as fuel, and a crankshaft of the engine 22 is connected to an input shaft of a transmission 24 via a starter (not shown).

The transmission 24 is configured as an automatic transmission such as 4-speed, 5-speed, 6-speed, 8-speed, etc., and includes an input shaft, an output shaft, a plurality of planetary gears, a plurality of friction engagement elements (clutch). And a brake), and a speed change actuator (solenoid valve, etc.) for engaging and disengaging a plurality of friction engagement elements. The input shaft is connected to the engine 22 via a starter and the output shaft is connected to the differential gear 26. It is connected to the drive wheels 28a and 28b through. This transmission 24 forms each shift stage by engaging and disengaging a plurality of friction engagement elements by a shift actuator, and transmits power between an input shaft and an output shaft.

The starter 30 is connected to the crankshaft of the engine 22 via a one-way clutch and is used to crank the engine 22. The alternator 32 is connected to the crankshaft of the engine 22 via a belt, and uses the power from the engine 22 to generate electricity. The battery 36 is configured as, for example, a lead storage battery, a lithium ion secondary battery, or a nickel hydrogen secondary battery, and is a component of the engine 22 (for example, a throttle motor for driving a throttle valve, a fuel injection valve, an ignition plug, etc.). ), a shift actuator of the transmission 24, a starter 30, an alternator 32, a brake actuator 44 of the hydraulic brake device 40, which will be described later, and the like, and are connected to each other via an electric power line.

The hydraulic brake device 40 includes brake wheel cylinders 46a to 46d attached to the drive wheels 28a and 28b and the driven wheels 28c and 28d, and a brake actuator 44. The brake actuator 44 has a solenoid valve or the like, and adjusts the hydraulic pressure of the brake wheel cylinders 46a to 46d to adjust the braking force applied to the drive wheels 28a and 28b and the driven wheels 28c and 28d. The brake actuator 44 is drive-controlled by a brake electronic control unit (hereinafter referred to as “brake ECU”) 48.

Although not shown, the brake ECU 48 is configured as a microprocessor centered on a CPU, and in addition to the CPU, includes a ROM that stores a processing program, a RAM that temporarily stores data, an input/output port, and a communication port. Prepare To the brake ECU 48, a master cylinder pressure (brake pedal force) from a pressure sensor (not shown) attached to the master cylinder 42 that produces a pressure corresponding to the depression of the brake pedal 65 is input via an input port. A drive control signal or the like to the brake actuator 44 is output from the brake ECU 48 via the output port. The brake ECU 48 is connected to the main ECU 50 via a communication port.

Although not shown, the main ECU 50 is configured as a microprocessor centered on a CPU, and in addition to the CPU, includes a ROM that stores a processing program, a RAM that temporarily stores data, an input/output port, and a communication port. Prepare Signals from various sensors are input to the main ECU 50 via input ports. Examples of the signals input to the main ECU 50 include signals from various sensors for detecting the states of the engine 22, the transmission 24, the starter 30, the alternator 32, and the battery 36. Moreover, the ignition signal from the ignition switch 60 and the shift position SP from the shift position sensor 62 which detects the operation position of the shift lever 61 can also be mentioned. Further, an accelerator opening Acc from an accelerator pedal position sensor 64 that detects the amount of depression of the accelerator pedal 63, a brake pedal position BP from a brake pedal position sensor 66 that detects the amount of depression of the brake pedal 65, and a vehicle speed sensor 68. The vehicle speed V can also be mentioned. In addition, a switch signal from the DAC permission switch 69 which permits the operation of the downhill assist control (DAC) control, and a switch signal from the CRAWL permission switch 70 which permits the operation of the crawl (CRAWL) control can be cited. Note that the DAC permission switch 69 and the CRAWL permission switch 70 are configured so that they can be turned on exclusively. The DAC control and CRAWL control will be described later. Various control signals are output from the main ECU 50 via the output port. Examples of signals output from the main ECU 50 include control signals to the engine 22, the transmission 24, the starter 30, and the alternator 32. As described above, the main ECU 50 is connected to the brake ECU 48 via the communication port.

In the vehicle 20 of the embodiment thus configured, the main ECU 50 basically performs the following basic traveling control. In the basic travel control, the target shift speed Gr* of the transmission 24 is set on the basis of the accelerator opening Acc and the vehicle speed V, and the transmission 24( is set so that the shift speed Gr of the transmission 24 becomes the target shift speed Gr*. Actuator). Further, the required torque Tin* required for the input shaft of the transmission 24 is set based on the accelerator opening Acc, the vehicle speed V, and the shift stage Gr of the transmission 24, and the required torque Tin* is the input shaft of the transmission 24. The target torque Te* of the engine 22 is set so as to be output to the engine 22 and the engine 22 is controlled.

Further, in the automobile 20, when the DAC permission switch 69 is turned on, the vehicle speed V is basically controlled by the coordinated control of the main ECU 50 and the brake ECU 48 even if the brake operation is not performed on the downhill road as the DAC control operation. The hydraulic brake device 40 is controlled so that is maintained at a relatively low predetermined speed V1 or less. Even if the DAC permission switch 69 is turned on, the above basic traveling control is performed when the accelerator is turned on.

Further, in the automobile 20, when the CRAWL permission switch 70 is turned on, the vehicle speed V is basically controlled by the cooperative control of the main ECU 50 and the brake ECU 48 even if the accelerator operation and the brake operation are not performed as the operation of the CRAWL control. The engine 22 and the hydraulic brake device 40 are controlled so that the engine speed is maintained at a relatively low predetermined vehicle speed V2. When the accelerator is on, the basic traveling control described above is performed.

Next, the operation of the automobile 20 of the embodiment will be described. FIG. 2 is a flowchart showing an example of a processing routine executed by the main ECU 50. This routine is executed when the DAC permission switch 69 or the CRAWL permission switch 70 is operated (when turned on or off or turned off).

When the processing routine of FIG. 2 is executed, the main ECU 50 determines whether the DAC permission switch 69 is on or off (step S100), and also determines whether the CRAWL permission switch 70 is on or off (step S110).

When both the DAC permission switch 69 and the CRAWL permission switch 70 are off, it is determined that the automatic stop and automatic start of the engine 22 are permitted (step S120), and this routine is ended. In this case, the main ECU 50 automatically stops the engine 22 when the automatic stop condition is satisfied while the vehicle is stopped, and cranks the engine 22 by the starter 30 when the automatic start condition is satisfied while the engine 22 is automatically stopped. Is automatically started. Here, as the automatic stop condition, for example, a condition that the accelerator is off and the brake is on while the vehicle is stopped is used. As the automatic start condition, for example, a condition in which the accelerator is turned on or the brake is turned off is used.

When the DAC permission switch 69 or the CRAWL permission switch 70 is on, it is determined that the automatic stop of the engine 22 is limited (step S120), and this routine is ended. In this case, the main ECU 50 prohibits the automatic stop of the engine 22 and continues the operation of the engine 22 during the operation of the engine 22. Further, during the automatic stop of the engine 22, the engine 22 is automatically started immediately (before the automatic start condition is satisfied) with the cranking of the engine 22 by the starter 30. When the engine 22 is automatically started, the voltage of the battery 36 may drop due to the power consumption of the starter 30. Therefore, when the automatic start condition is satisfied and the engine 22 is automatically started, electric power required for DAC control and CRAWL control after starting, for example, electric power required for controlling the solenoid valve of the brake actuator 44 and operation control of the engine 22. There is a possibility that the electric power required for the vehicle cannot be sufficiently secured, and the accuracy of the DAC control and the CRAWL control after starting the vehicle may deteriorate. In the embodiment, when the DAC permission switch 69 or the CRAWL permission switch 70 is on, the automatic stop of the engine 22 is limited to prevent the voltage drop of the battery 36 caused by the automatic start of the engine 22 at the start. It is possible to secure sufficient electric power required for DAC control and CRAWL control after starting. As a result, it is possible to prevent the accuracy of the DAC control and the CRAWL control after starting from decreasing.

FIG. 3 is an explanatory diagram showing an example of the state of the engine 22, the brake pedal position BP, the hydraulic pressures of the brake wheel cylinders 46a to 46d, the vehicle speed V, and the voltage Vb of the battery 36 when the DAC permission switch 69 is on. .. In the figure, the solid line shows the state of the example, and the one-dot chain line and the two-dot chain line show the state of the comparative example. In the comparative example, the engine 22 is automatically stopped and automatically started even when the DAC permission switch 69 is turned on.

In the comparative example, when the engine 22 is automatically stopped while the vehicle is stopped on a downhill road and the brake pedal position BP becomes the value 0 (the brake is turned off) at time t1, the engine 22 is automatically started. When the DAC control is activated, the hydraulic pressure of the brake wheel cylinders 46a to 46d is excessively decreased and the vehicle speed V overshoots the predetermined vehicle speed V1 (see the chain line in the figure). The decrease in the hydraulic pressure at 46d may be insufficient and the time taken for the vehicle speed V to reach the predetermined vehicle speed V1 may become long (see the chain double-dashed line in the figure). On the other hand, in the embodiment, since the operation of the engine 22 is continued without automatically stopping the engine 22 while the vehicle is stopped, the voltage of the battery 36 drops after the brake pedal position BP becomes 0 at time t1. Absent. As a result, the DAC control can be operated accurately after starting the vehicle.

In the vehicle 20 of the embodiment described above, the automatic stop of the engine 22 is limited when the DAC permission switch 69 or the CRAWL permission switch 70 is on. As a result, it is possible to prevent the voltage of the battery 36 from dropping due to the automatic start of the engine 22 at the time of starting, and to sufficiently secure the electric power required for the DAC control and the CRAWL control after the start. As a result, it is possible to prevent the accuracy of the DAC control and the CRAWL control after starting from decreasing.

In the vehicle 20 of the embodiment, the automatic stop of the engine 22 is limited when the DAC permission switch 69 or the CRAWL permission switch 70 is turned on. However, it is not the DAC permission switch 69 or the CRAWL permission switch 70 but other conditions. The automatic stop of the engine 22 may be restricted when the operation of the DAC control or the CRAWL control is permitted by. Further, the automatic stop of the engine 22 may be limited when the brake ECU 48 recognizes that the DAC control or the CRAWL control is operating.

The vehicle 20 of the embodiment is a vehicle that can selectively execute the DAC control and the CRAWL control. However, it may be a vehicle that can execute only DAC control or a vehicle that can only execute CRAWL control.

In the vehicle 20 of the embodiment, the battery 36 is used as the power storage device, but a capacitor may be used.

Correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem will be described. In the embodiment, the engine 22 corresponds to the “engine”, the starter 30 corresponds to the “starter”, the hydraulic brake device 40 corresponds to the “braking force applying device”, the battery 36 corresponds to the “power storage device”, The main ECU 50 and the brake ECU 48 correspond to “control device”.

The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the section of means for solving the problem. This is an example for specifically explaining the mode for carrying out the invention, and does not limit the elements of the invention described in the column of means for solving the problem. That is, the interpretation of the invention described in the column of means for solving the problem should be made based on the description in that column, and the embodiment is the invention of the invention described in the column of means for solving the problem. This is just a specific example.

Although the embodiments for carrying out the present invention have been described above with reference to the embodiments, the present invention is not limited to these embodiments, and various embodiments are possible within the scope not departing from the gist of the present invention. Of course, it can be implemented.

INDUSTRIAL APPLICABILITY The present invention can be used in the vehicle manufacturing industry and the like.

20 automobile, 22 engine, 24 transmission, 26 differential gear, 28a, 28b drive wheel, 28c, 28d driven wheel, 30 starter, 32 alternator, 36 battery, 40 hydraulic brake device, 42 master cylinder, 44 brake actuator, 46a- 46d brake wheel cylinder, 48 electronic control unit for brake (brake ECU), 50 main electronic control unit (main ECU), 60 ignition switch, 61 shift lever, 62 shift position sensor, 63 accelerator pedal, 64 accelerator pedal position sensor, 65 Brake pedal, 66 brake pedal position sensor, 68 vehicle speed sensor, 69 DAC permission switch.

Claims (1)

An engine for driving,
A starter for cranking the engine,
A braking force applying device capable of applying a braking force to wheels,
A power storage device connected to the engine, the starter, and the braking force applying device via a power line;
The engine, the starter, and the braking force application device are controlled, and when the automatic stop condition is satisfied, the engine is automatically stopped, and when the automatic start condition is satisfied during the automatic stop of the engine, the starter controls the engine. A control device for automatically starting the engine with cranking,
A vehicle comprising:
The control device limits the automatic stop of the engine at the time of permitting or operating the downhill assist control control or the crawl control,
vehicle.

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