Vehicle control system

Abstract

We propose a vehicle control device that can stably maintain the stopped state of a vehicle through stop-hold control. [Solution] The ECU2 of the stop-maintaining system 1 includes a seating determination unit 21 that determines whether or not each seat in the vehicle is occupied, a braking force control unit 23 that controls the braking force to maintain the vehicle's stopped state based on the seating determination information of each seat determined by the seating determination unit 21, and a driving force control unit 24 that controls the driving force when the vehicle starts moving based on the seating determination information of each seat determined by the seating determination unit 21. This makes it possible to stably maintain the stopped state of the vehicle by stop-maintaining control and to obtain appropriate driving force when the vehicle starts moving.

Description

Technical Field

[0001] The present invention relates to a vehicle control device. In particular, the present invention relates to an improvement in stop maintenance control (brake hold control).

Background Art

[0002] As one of the driving support technologies in a vehicle, for example, stop maintenance control that holds braking force so as to maintain a stopped state even when the driver releases the depression of the brake pedal in a stopped state while waiting for a signal or on an uphill road has been proposed. According to this stop maintenance control, the stopped state of the vehicle can be maintained without the driver having to continuously depress the brake pedal, and the driving load on the driver can be reduced.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, in stop maintenance control, it is necessary to adjust the braking force in order to obtain good starting performance during restart while maintaining the stopped state of the vehicle. However, if the vehicle weight is different, the appropriate braking force for maintaining the stopped state and achieving good starting performance will also be different.

[0005] The inventor of the present invention focused on the fact that the vehicle weight varies greatly depending on the number of passengers. And, the inventor obtained the knowledge that if the braking force in stop maintenance control is set regardless of the number of passengers, there is a possibility that there will be an excess or deficiency in the braking force for maintaining the stopped state (an appropriate braking force cannot be obtained). Also, the inventor obtained the knowledge that even when the vehicle starts from a state where stop maintenance control is being performed, the appropriate starting driving force differs depending on the vehicle weight.

[0006] The present invention has been made in view of the above, and its objective is to propose a vehicle control device that can stably maintain the stopped state of a vehicle by stop-maintain control and can appropriately obtain driving force when the vehicle starts moving. [Means for solving the problem]

[0007] The present invention provides a solution for achieving the above objective, which is based on a vehicle control device capable of stop-maintain control that maintains braking force to keep the vehicle stopped even when the driver releases the brake pedal. This vehicle control device is characterized by comprising: a seating determination unit that determines whether or not a person is seated in each seat of the vehicle; a braking force control unit that controls the braking force to maintain the vehicle stopped based on the seating determination information of whether or not a person is seated in each seat by the seating determination unit; and a driving force control unit that controls the driving force when the vehicle starts moving based on the seating determination information of whether or not a person is seated in each seat by the seating determination unit.

[0008] The weight of the vehicle varies depending on whether each seat is occupied. Furthermore, the appropriate braking force required to maintain the vehicle's stationary state, and the appropriate driving force (starting driving force) when the vehicle starts, differ depending on the vehicle's weight. Taking this into consideration, this solution controls the braking force and driving force based on the determination information of whether each seat is occupied. This makes it possible to stably maintain the vehicle's stationary state through stop-maintaining control, and to obtain the appropriate driving force when the vehicle starts. [Effects of the Invention]

[0009] In this invention, the braking force to maintain the vehicle's stopped state and the driving force when the vehicle starts are controlled based on information determining whether or not each seat in the vehicle is occupied. As a result, the vehicle's stopped state can be stably maintained by the stop-maintain control, and the driving force when the vehicle starts can be appropriately obtained. [Brief explanation of the drawing]

[0010] [Figure 1] This block diagram shows a schematic of the control system of the stop-and-maintain system according to the embodiment. [Figure 2] This is a flowchart illustrating the procedure for stop-and-maintain control in the embodiment. [Modes for carrying out the invention]

[0011] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0012] This embodiment describes the application of the present invention to a conventional vehicle equipped with an engine (internal combustion engine) as a driving force source. However, the present invention is not limited to this and can also be applied to electric vehicles and fuel cell vehicles equipped with an electric motor as a driving force source. Furthermore, the present invention can also be applied to hybrid vehicles and plug-in hybrid vehicles equipped with both an engine and an electric motor as driving force sources. In addition, in this embodiment, in order to facilitate understanding of the invention, the stopped state of a vehicle on an uphill road is given as an example of the implementation of stop-maintain control, but the present invention is not limited to this and can be applied to various situations such as the stopped state of a vehicle waiting at a traffic light, and the conditions for its implementation are not particularly limited.

[0013] -Outline configuration of the control system for the stop-and-maintain system- Figure 1 is a block diagram illustrating the schematic control system of the stop-maintaining system 1 according to this embodiment. As shown in Figure 1, the stop-maintaining system 1 according to this embodiment includes an ECU 2 that performs stop-maintaining control, for example, when the vehicle is stopped on an uphill road, by maintaining braking force so that the stopped state is maintained even when the driver releases the brake pedal. The ECU 2 includes a processor such as a CPU (Central Processing Unit), a ROM (Read-Only Memory) for storing control programs, a RAM (Random-Access Memory) for temporarily storing data, and input / output ports, etc.

[0014] The ECU2 is connected to a gradient sensor 31, a G sensor 32, a brake pedal switch 33, an accelerator pedal position sensor 34, a wheel speed sensor 35, seat occupancy sensors 36, 36, ..., a brake actuator 41, and a throttle actuator 42.

[0015] The gradient sensor 31 detects the gradient of the road surface and transmits the road surface gradient information to the ECU2. The G sensor 32 detects the vehicle's G (acceleration) and transmits the acceleration information to the ECU2. The brake pedal switch 33 detects the driver's brake pedal depressing operation (depressing operation and depressing operation) and transmits the detection information to the ECU2. The accelerator pedal position sensor 34 detects the amount the driver depresses the accelerator pedal (accelerator position) and transmits the detection information to the ECU2. The wheel speed sensor 35 detects the rotational speed of the wheels to detect the vehicle speed and transmits the detection information to the ECU2. The seat occupancy sensors 36, 36, ... are installed in the seat cushions of each seat, including the driver's seat and passenger seat, and detect whether or not an occupant is seated in the seat and transmit the detection information (seating information) to the ECU2.

[0016] The brake actuator 41 controls the braking force of the vehicle and adjusts the brake hydraulic pressure of the wheel cylinders of the wheels in accordance with the control signal input from the ECU 2. The adjustment of brake hydraulic pressure here includes adjusting the brake hydraulic pressure to maintain braking force so that the vehicle remains stopped even when the driver releases the brake pedal during stop-maintain control.

[0017] The throttle actuator 42 controls the vehicle's driving force and adjusts the opening degree of the engine's throttle valve in accordance with the control signal input from the ECU 2. This adjustment of the throttle valve opening degree includes adjusting the driving force from the engine to obtain good starting performance when the vehicle starts moving (restarts) from a state where stop-maintain control is in place.

[0018] As functional units realized by the control program, the ECU 2 includes a seating determination unit 21, a vehicle weight calculation unit 22, a braking force control unit 23, and a driving force control unit 24. The seating determination unit 21 receives seating information from each of the seating sensors 36, 36,... and determines the number of seats on which passengers are seated among the seats of the vehicle. This number of seats on which passengers are seated will be used as information on the number of passengers, which will be described later.

[0019] The vehicle weight calculation unit 22 calculates the current vehicle weight including the weight of the passengers. Specifically, since the vehicle weight not including the weight of the passengers is defined in advance, the vehicle weight (total vehicle weight) is calculated by adding the total weight of the passengers obtained by multiplying the number of passengers by a predetermined weight to this vehicle weight. Since the weight of each individual passenger varies depending on their build and age, it is also possible to define the weight of each individual passenger taking these into account, or to equip the seating sensors with a weight measurement function, and add the sum of the weights of each individual passenger measured by each of the seating sensors 36, 36,... as the total weight of the passengers to calculate the vehicle weight.

[0020] The braking force control unit 23 controls the braking force for maintaining the stopped state of the vehicle according to the current vehicle weight including the weight of the passengers calculated by the vehicle weight calculation unit 22. Specifically, the greater the vehicle weight (including the weight of the passengers), the greater the braking force of the vehicle obtained by the brake actuator 41 is set during the implementation of the stop maintenance control. Although the required braking force for maintaining the stopped state of the vehicle increases as the vehicle weight increases, considering that if this braking force is too large, the startability (re-startability) of the vehicle during starting will deteriorate, it is set through experiments and simulations.

[0021] More specifically, in the present embodiment, when the number of passengers (the number of seated persons) is less than a predetermined number, the braking force of the vehicle obtained by the brake actuator 41 is set to be relatively small, and when the number of passengers is greater than or equal to the predetermined number, the braking force of the vehicle obtained by the brake actuator 41 is set to be relatively large. In the present embodiment, the braking force of the vehicle is switched in two steps in this way, but it may be switched in three or more steps.

[0022] The driving force control unit 24 controls the driving force of the vehicle at the time of starting according to the current vehicle weight including the weight of the passengers calculated by the vehicle weight calculation unit 22. Specifically, the greater the vehicle weight (including the weight of the passengers), the greater the throttle opening obtained by the throttle actuator 42 at the time of starting the vehicle from the stop maintenance control, and the greater the driving force of the vehicle is set. Although this driving force increases as the vehicle weight increases and the driving force required to start the vehicle on an uphill road becomes greater, considering that if this driving force is too large, it may give the passengers a sense of discomfort due to the sudden acceleration of the vehicle, it is set by experiments and simulations.

[0023] More specifically, in the present embodiment, when the number of passengers (the number of seated persons) is less than a predetermined number, the throttle opening obtained by the throttle actuator 42 is made relatively small to set the driving force of the vehicle small, and when the number of passengers is greater than or equal to the predetermined number, the throttle opening obtained by the throttle actuator 42 is made relatively large to set the driving force of the vehicle large. In the present embodiment, the driving force of the vehicle is switched in two steps in this way, but it may be switched in three or more steps.

[0024] -Processing operation of the stop maintenance system- Next, the stop maintenance control in the stop maintenance system configured as described above will be described. FIG. 2 is a flowchart showing the procedure of the stop maintenance control in the present embodiment.

[0025] First, in step ST1, it is determined whether the conditions for executing stop-and-maintain control have been met. These conditions include, for example, the determination that it is an uphill road based on road surface gradient information from the gradient sensor 31, and the determination that the driver has released the brake pedal based on detection information from the brake pedal switch 33. If the conditions for executing stop-and-maintain control have not been met and the result in step ST1 is NO, the process ends without executing stop-and-maintain control.

[0026] On the other hand, if the conditions for executing stop-maintain control are met and a YES determination is made in step ST1, the process moves to step ST2 to determine whether the number of people seated in the vehicle is greater than or equal to a predetermined number A (for example, 3). This determination is made based on seating information from each seating sensor 36, 36, ... If the number of people seated in the vehicle is less than the predetermined number A and a NO determination is made in step ST2, the process moves to step ST3 to set the brake hydraulic pressure set in stop-maintain control to a lower value. In other words, the braking force of the vehicle obtained by the brake actuator 41 is set to a relatively small value. On the other hand, if the number of people seated in the vehicle is greater than or equal to the predetermined number A and a YES determination is made in step ST2, the process moves to step ST4 to set the brake hydraulic pressure set in stop-maintain control to a higher value. In other words, the braking force of the vehicle obtained by the brake actuator 41 is set to a relatively large value.

[0027] In step ST5, stop-maintain control is performed using the brake hydraulic pressure set in this manner. In other words, if the number of people seated in the vehicle is less than a predetermined number A, stop-maintain control is performed with a relatively small braking force obtained by the brake actuator 41, while if the number of people seated in the vehicle is A or more, stop-maintain control is performed with a relatively large braking force obtained by the brake actuator 41.

[0028] In this state where stop-maintain control is being performed, step ST6 determines whether the conditions for releasing the stop-maintain control have been met. For example, these conditions include the driver pressing the accelerator pedal, which is recognized by the accelerator pedal position sensor 34. If the conditions for releasing the stop-maintain control have not been met and step ST6 determines NO, the process returns to step ST5, and the stop-maintain control using the brake hydraulic pressure set as described above is continued.

[0029] On the other hand, if the conditions for releasing the stop-maintain control are met and a YES determination is made in step ST6, the process moves to step ST7 to determine whether the number of people seated in the vehicle is greater than or equal to a predetermined number A (for example, 3). This determination is also made based on seating information from each seating sensor 36, 36, ... If the number of people seated in the vehicle is less than the predetermined number A and a NO determination is made in step ST7, the process moves to step ST8 to set a smaller driving force when the vehicle starts. In other words, the opening degree of the engine throttle valve obtained by the throttle actuator 42 is set to a relatively small value. On the other hand, if the number of people seated in the vehicle is greater than or equal to the predetermined number A and a YES determination is made in step ST7, the process moves to step ST9 to set a larger driving force when the vehicle starts. In other words, the opening degree of the engine throttle valve obtained by the throttle actuator 42 is set to a relatively large value.

[0030] In step ST10, the brake hydraulic pressure is released, and vehicle starting control is performed based on the throttle valve opening degree set as described above (vehicle starting control is performed based on the set time-driven force). In other words, if the number of people seated in the vehicle is less than a predetermined number A, vehicle starting control is performed with a relatively small opening degree of the engine's throttle valve obtained by the throttle actuator 42, whereas if the number of people seated in the vehicle is A or more, vehicle starting control is performed with a relatively large opening degree of the engine's throttle valve obtained by the throttle actuator 42.

[0031] This process is repeated each time the stop-and-maintain control is executed.

[0032] -Effects of the embodiment- As described above, in this embodiment, the braking force to maintain the vehicle's stopped state and the driving force when the vehicle starts are controlled based on the determination information of whether or not each seat in the vehicle is occupied. Therefore, the vehicle's stopped state can be stably maintained by the stop-maintain control, and the driving force when the vehicle starts can be appropriately obtained.

[0033] -Other Embodiments- Furthermore, the present invention is not limited to the embodiments described above, and all modifications and applications are possible within the scope of the claims and equivalents thereof.

[0034] For example, in the above embodiment, seat sensors 36, 36, ... were used as a means to detect whether or not an occupant was seated in a seat. The present invention is not limited to this, and the interior of the vehicle may be photographed by a camera, and the number of people seated in the seats may be recognized from the information of the acquired image.

[0035] Furthermore, in the above embodiment, the driving force at the time of vehicle startup was set by adjusting the opening degree of the throttle valve using the throttle actuator 42. The present invention is not limited to this, and the driving force at the time of vehicle startup may also be set by adjusting the amount of fuel injected from the injector. In addition, in vehicles equipped with an electric motor for driving, the driving force at the time of vehicle startup is set by adjusting the output torque of the electric motor. [Industrial applicability]

[0036] The present invention is applicable to vehicles capable of stop-and-maintain control. [Explanation of symbols]

[0037] 1. Stop Maintenance System 2 ECU 21 Seating determination unit 23 Brake Force Control Unit 24 Drive Force Control Unit 33 Brake pedal switch 34. Accelerator position sensor 36. Seat occupancy sensor 41 Brake actuator 42 Throttle Actuator

Claims

[Claim 1] In a vehicle control device capable of stop-maintain control that maintains braking force to keep the vehicle stopped even when the driver releases the brake pedal, A seating determination unit that determines whether or not each seat in the vehicle is occupied, Based on the seating determination information of whether or not each seat is occupied by the seating determination unit, a braking force control unit controls the braking force to maintain the vehicle in a stopped state. A vehicle control device comprising: a driving force control unit that controls the driving force when the vehicle starts based on the determination information of whether or not each seat is occupied by the seating determination unit.

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