JP2004009751A - Vehicle speed control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle speed control device capable of traveling at an appropriate slow speed even when traveling down a steep slope and preventing erroneous restart by actuating a parking brake surely after the vehicle stops. <P>SOLUTION: The vehicle speed control device is equipped with an engine 9 for driving the vehicle, a rotational frequency sensor 12 of the engine 9, a throttle opening sensor 8 interlocked with an accelerator 1, vehicle speed sensors 4 and 5 for detecting the speed of the vehicle, and a control circuit 3 for making the engine 9 and brakes 18, 19 automatically operate according to an indicated vehicle speed. The control circuit 3 controls the brakes 18 and 19 during a normal traveling according to a first indicated vehicle speed limiting the maximum speed of the vehicle to a certain speed, and when the braking force of the brakes 18 and 19, the rotational frequency of the engine 9, and the throttle opening meet the prescribed set condition, the brakes 18 and 19 are controlled according to a slower second indicated vehicle speed in place of the first indicated vehicle speed. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vehicle speed control device that limits the speed of a vehicle such as a golf cart.
[0002]
[Prior art]
The vehicle speed control of the vehicle is performed by the driver operating an accelerator and a brake, but a vehicle such as a golf cart has a brake motor for automatically applying a brake separately from a brake pedal to enable automatic traveling. The vehicle is provided with a control circuit (CPU) for driving and controlling a vehicle drive source (for example, an engine). The CPU drives the brake motor based on the instructed vehicle speed with the maximum speed limited during normal running. In this way, the vehicle speed is limited and the maximum speed is set to a certain constant speed (instructed vehicle speed) to ensure safety.
[0003]
On the other hand, the vehicle is provided with an electromagnetic brake (parking brake) separately from the brake for controlling the vehicle speed to prevent the vehicle from running erroneously after the vehicle stops and the driver gets off the vehicle.
[0004]
[Problems to be solved by the invention]
However, in a vehicle such as a golf cart having the above-described conventional vehicle speed control device, even if the maximum speed is limited by the indicated vehicle speed, the speed may be felt to be too fast on a steep downhill. In a golf cart or the like, a belt-type continuously variable transmission (CVT) is used to transmit a driving force from an engine to an axle on a driven side. Since the CVT is a belt type, it is difficult to apply an engine brake, so that when the vehicle goes down a steep hill, the vehicle tends to be at a high speed, and it is difficult to appropriately control the vehicle speed.
[0005]
Parking brakes that prevent erroneous running of the vehicle, for example, in the case of a golf cart, may not apply the parking brake too quickly when playing quickly, and when the vehicle is stopped on a slope, the vehicle will continue running There was a risk of doing so. Automatic parking brakes have conventionally been used to prevent such forgetting to apply the parking brake. However, since the conventional automatic parking brake operates by detecting that the vehicle has stopped (vehicle speed is zero), if the driver gets off before the vehicle stops when the vehicle is in a very low speed state, the driver's intention to stop is given. Regardless of the above, the automatic parking brake did not operate, and when the vehicle was stopped on a slope, there was a possibility that the vehicle would travel as it was.
[0006]
The present invention has been made in consideration of the above-described conventional technology, and can travel at an appropriate slow speed even when descending a steep hill, and reliably operates a parking brake after the vehicle stops to prevent erroneous traveling of the vehicle. It is an object of the present invention to provide a vehicle speed control device for preventing the vehicle speed.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, a drive source for driving a vehicle, a rotation speed sensor of the drive source, a sensor for an output control parameter of the drive source connected to an accelerator operated by a driver, and a vehicle A vehicle speed sensor that detects the speed of the vehicle, and a control circuit that automatically operates a drive source and a brake based on the indicated vehicle speed, wherein the control circuit keeps the maximum speed of the vehicle constant during normal running. A brake is controlled based on a first command vehicle speed that is limited to a speed, and a braking force of the brake and a speed limit that is lower than the first command vehicle speed when the output control parameter is a predetermined setting condition is replaced with the first command vehicle speed. (2) Provided is a vehicle speed control device that controls a brake based on a designated vehicle speed.
[0008]
According to this configuration, in accordance with the gradient of a downhill or the like on which the vehicle travels, the gradient is determined in advance by a brake braking force corresponding to the gradient and an output control parameter of a drive source (for example, an engine throttle opening or an electric motor). The current vehicle speed is determined on the basis of the set condition of the current value of the vehicle, and when the set condition is satisfied, the command vehicle speed for limiting the maximum speed is changed from the first command vehicle speed to the second command vehicle speed lower than the first command vehicle speed. On a slope, the vehicle can travel with a sense of security at an appropriate slow speed.
[0009]
In a preferred configuration example, the braking force of the brake is calculated by the control circuit based on a difference between a vehicle speed detected by the vehicle speed sensor and the indicated vehicle speed.
[0010]
According to this configuration, the brake braking force is calculated based on the difference between the instructed vehicle speed and the actual speed, and the inclination is determined based on the calculated braking force. The vehicle speed can be controlled by detecting the inclination using the CPU.
[0011]
In a preferred configuration example, when the setting condition is not satisfied, the accelerator may be fully opened based on the second instruction vehicle speed if the accelerator is off, or based on the first instruction vehicle speed if the accelerator is partial, depending on the accelerator operation state. For example, the brake is controlled based on the first designated vehicle speed.
[0012]
According to this configuration, when the setting condition for switching from the first instruction vehicle speed to the second instruction vehicle speed is not satisfied, the operation state of the accelerator is determined, and if the accelerator is off, it is determined that there is an intention to decelerate, and the second instruction vehicle speed is determined. To reduce the speed limit. Thereby, the effect of the engine brake is substantially obtained.
[0013]
Further, in the present invention, a vehicle speed sensor for detecting the speed of the vehicle, a brake operating means for operating the brake, an accelerator for adjusting the output of the vehicle drive source, and a brake motor for operating the brake separately from the brake operating means A vehicle speed control device having a parking brake that prevents erroneous traveling of a stopped vehicle, wherein the accelerator and the brake operating means are off, and the vehicle is driven by driving the brake motor when the vehicle speed is lower than a predetermined speed. There is provided a vehicle speed control device having a control circuit for automatically operating the parking brake after stopping.
[0014]
According to this configuration, if the speed is lower than the predetermined low speed and the accelerator and the brake pedal are off, it is determined that the occupant has already exited, the brake motor is operated to stop the vehicle, and then the parking brake is automatically activated. It can be operated to prevent forgetting to apply the parking brake and insufficient parking brake operation.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a schematic block diagram of a vehicle speed control device according to the present invention.
A vehicle such as a golf cart is provided with an accelerator pedal 1 and a brake pedal 2, and the operation amounts of these by a driver are input to a CPU (control circuit) 3 mounted on the vehicle. The engine 9 has a carburetor 11 and a throttle opening sensor 8 for detecting the opening of a throttle valve (not shown). The engine 9 is provided with an engine speed sensor 12. The detection outputs of the throttle opening sensor 8 and the engine speed sensor 12 are input to the CPU 3. The output of the engine 9 is transmitted to the transmission 6 via the automatic transmission 13 of a belt type, and drives the rear wheels 14. The transmission 6 is provided with vehicle speed sensors 4 and 5, and vehicle speed detection data is input to the CPU. The transmission 6 is provided with a parking brake 10 composed of an electromagnetic brake.
[0016]
The brake pedal 2 is connected to a brake drive mechanism 15, and operates a drum brake 18 of a front wheel 17 and a drum brake 19 of a rear wheel 14 via wires 16. A brake motor 20 is further connected to the brake drive mechanism 15. The brake motor 20 is driven by a brake motor driver 21. The brake motor driver 21 is driven by the CPU 3. The CPU 3 is connected to an engine speed sensor 12, a throttle opening sensor 8, vehicle speed sensors 4 and 5, an accelerator opening sensor 21 for detecting an amount of depression of an accelerator pedal 1, and a depression amount detection sensor (not shown) for the brake pedal 2. Based on these detection signals, the driving of the throttle valve of the carburetor 11 and the brake motor 20 are controlled to control the vehicle speed.
[0017]
FIG. 2 is a flowchart showing the vehicle speed control according to the present invention.
The vehicle travels with the maximum speed limited to a predetermined speed (first instruction vehicle speed) (step S1). The first designated vehicle speed is set to a speed at which the vehicle can safely travel on a flat road. During traveling, the CPU 3 (FIG. 1) determines whether the average braking force is equal to or greater than the set value A, the throttle opening is less than the set value B, or the average engine speed is less than the set value C as necessary. (Step S2). The determination of the engine speed is a conditional expression provided so that the determination of the average braking force and the throttle opening described above may cause erroneous recognition even when the vehicle exceeds the first instructed vehicle speed after the start acceleration. Instead of the condition of the engine speed, the determination can be made by using another means such as measuring the time after the start using a timer. The average braking force is a value of a force corresponding to a difference between the actual vehicle speed and the indicated vehicle speed when the actual vehicle speed is detected by the vehicle speed sensors 4 and 5 (FIG. 1). The throttle opening is detected by a throttle opening sensor 8 (FIG. 1). The average engine speed is measured by the speed sensor 12 (FIG. 1). As the set values A, B, and C, values corresponding to the gradients when the vehicle goes down the slope are measured and input in advance.
[0018]
If all of the above conditions are satisfied, it is determined that the vehicle is traveling down a hill, and the maximum speed is set to the second instruction vehicle speed lower than the first instruction vehicle speed (step S3). As a result, the brake motor driver 7 (FIG. 1) drives the brake motor 20 (FIG. 1) to further apply a braking force to the vehicle. You can drive safely at a slow speed. If at least one of the parameters for the automatic downhill deceleration determination does not apply, the vehicle remains at the first designated vehicle speed (step S4).
[0019]
When the vehicle is at the second designated vehicle speed, the CPU 3 (FIG. 1) determines whether or not the average braking force is less than the set value D and the average engine speed is equal to or more than the set value E to release the automatic deceleration for descending slope (step S5). If this condition is not met, the CPU further determines whether or not the throttle opening is above the set value F and a predetermined time has elapsed with the throttle opening still being greater than or equal to the throttle opening (step S6). If this is not the case, it is determined that the vehicle is still down the slope, and the second designated vehicle speed is maintained (step S7). If at least one of the conditions in steps S5 and S6 is satisfied, the vehicle is determined to have descended down a hill and is returned to the first designated vehicle speed (step S8). As the set values D, E, and F, a value corresponding to the inclination when the vehicle goes down a slope having a small inclination is measured and input in advance.
[0020]
In this way, by changing the indicating vehicle speed when the vehicle is on a steep slope, a gentle slope, or when the vehicle has finished descending, it is possible to provide an appropriate indicating vehicle speed according to the running state of the vehicle and to drive safely at an appropriate slow speed. Thus, the inclination can be detected and the vehicle speed can be controlled by using a CPU provided in a conventional vehicle without using an inclination sensor or the like when determining the inclination. Although this flowchart is an example of a vehicle using an engine as a drive source, it is also applicable to an electric vehicle using an electric motor as a drive source. In this case, the E / G rotation speed in the figure is the motor rotation speed. And the throttle opening for controlling the output of the drive source is replaced with the motor current.
[0021]
FIG. 3 is a flowchart showing another vehicle speed control according to the present invention.
The vehicle runs at the first designated vehicle speed (step T1). During traveling, the CPU 3 (FIG. 1) automatically determines whether the average braking force is equal to or greater than the set value A, the throttle opening is less than the set value B, or the average engine speed is less than the set value C. A determination is made (step T2), and if all the conditions are satisfied, the second designated vehicle speed is set (step T3). If even one of these conditions is not satisfied, the CPU determines the accelerator work (the amount of depression of the accelerator pedal) (step T4). When the driver does not step on the accelerator, that is, when the accelerator is off, even if it is determined in step T2 that the vehicle is not driving downhill, it is determined that the driver has an intention not to speed up, and the second instruction vehicle speed is set. The motor driver 7 (FIG. 1) operates to brake the running of the vehicle (step T5). As a result, when the accelerator is off, the maximum speed is always set to the second designated vehicle speed, so that the effect of the engine brake is substantially obtained, and vehicle speed control appropriately corresponding to the driver's intention can be performed.
[0022]
When the driver is slightly depressing the accelerator, that is, in the case of the accelerator partial, the vehicle is driven at a speed corresponding to the accelerator operation amount within the range of the first instruction vehicle speed without changing the instruction vehicle speed (step T6). If the driver has fully depressed the accelerator, the first commanded vehicle speed is maintained (step T7). Thus, regardless of whether the vehicle is traveling on a downhill or not, the vehicle can be braked in consideration of the driver's intention, so that the vehicle speed can be controlled more safely.
[0023]
FIG. 4 is a flowchart of the automatic operation control of the parking brake according to the present invention.
While the vehicle is running (step U1), the CPU 3 (FIG. 1) determines whether the current vehicle speed (actual vehicle speed) of the vehicle is lower than the predetermined speed G, the accelerator is off, and the operation of the brake pedal is off. . If at least one of the conditions is not satisfied, the traveling is continued (step U3). When all of these conditions are satisfied, the driver intends to stop, or determines that the vehicle has got off without stopping without fail, and operates the brake motor 20 (FIG. 1) to brake the vehicle (step U4). And stop (step U5). The predetermined speed G is set to a low value such that the vehicle is about to stop. Thereafter, the CPU automatically turns on the electromagnetic brake (parking brake) to surely stop the vehicle. As a result, the vehicle can be reliably stopped, and the vehicle does not run erroneously on a slope or the like.
[0024]
【The invention's effect】
As described above, according to the present invention, in accordance with the gradient of a downhill or the like on which the vehicle travels, the gradient is determined in advance by the braking force corresponding to the gradient, the engine speed (or the motor speed). In order to change the instruction vehicle speed for limiting the maximum speed from the first instruction vehicle speed to the second instruction vehicle speed lower than the first instruction vehicle speed, the determination is made based on the setting condition of the throttle opening (or the motor current value). On a downhill, it is possible to travel with a sense of security at an appropriate slow speed.
[0025]
Further, since the braking force is calculated based on the difference between the instructed vehicle speed and the actual speed, and the inclination is determined based on the braking force, the CPU provided in the vehicle is conventionally used without using a tilt sensor or the like. The vehicle speed can be controlled by determining the inclination.
[0026]
When the setting condition for switching from the first instruction vehicle speed to the second instruction vehicle speed is not satisfied, the operation state of the accelerator is determined. If the accelerator is off, it is determined that there is an intention to decelerate, and the operation is switched to the second instruction vehicle speed to limit the operation. Decrease speed. Thereby, the effect of the engine brake is substantially obtained.
[0027]
Further, if the speed is lower than a predetermined low speed and the accelerator and the brake pedal are off, it is determined that the occupant has already got off the vehicle, the brake motor is operated to stop the vehicle, and then the parking brake is automatically operated. It is possible to prevent forgetting to apply the parking brake and insufficient parking brake operation.
[Brief description of the drawings]
FIG. 1 is a schematic block diagram of a vehicle speed control device according to the present invention.
FIG. 2 is a flowchart showing vehicle speed control according to the present invention.
FIG. 3 is a flowchart showing another vehicle speed control of the present invention.
FIG. 4 is a flowchart of an automatic operation control of the parking brake according to the present invention.
[Explanation of symbols]
1: accelerator pedal, 2: brake pedal, 3: CPU, 4: vehicle speed sensor,
5: vehicle speed sensor, 6: transmission, 7: brake motor driver,
8: throttle opening detector, 9: engine, 10: electromagnetic brake,
11: vaporizer, 12: rotation speed sensor, 13: automatic transmission, 14: rear wheel,
15: brake drive mechanism, 16: wire, 17: front wheel,
18: drum brake, 19: drum brake, 20: brake motor,
21: accelerator opening sensor.

Claims (4)

A drive source for driving the vehicle,
A rotation speed sensor of the drive source,
A sensor of an output control parameter of a drive source connected to an accelerator operated by a driver,
A vehicle speed sensor for detecting the speed of the vehicle,
A control circuit for automatically operating the drive source and the brake based on the instructed vehicle speed,
The control circuit controls a brake based on a first instruction vehicle speed that limits the maximum speed of the vehicle to a constant speed during normal traveling, and when the braking force of the brake and the output control parameter are under predetermined setting conditions, A vehicle speed control device, wherein a brake is controlled based on a second instruction vehicle speed having a lower speed limit than the first instruction vehicle speed. The vehicle speed control device according to claim 1, wherein the control circuit calculates the braking force of the brake based on a difference between a vehicle speed detected by the vehicle speed sensor and the instructed vehicle speed. When the set conditions are not satisfied, the accelerator operation state is based on the second instruction vehicle speed if the accelerator is off, the first instruction vehicle speed if the accelerator is partial, and the first instruction vehicle speed if the accelerator is fully open, depending on the accelerator operation state. The vehicle speed control device according to claim 1, wherein the brake is controlled based on the vehicle speed. A vehicle speed sensor for detecting the speed of the vehicle,
Brake operating means for operating the brake;
An accelerator for adjusting the output of the vehicle drive source;
A brake motor that operates a brake separately from the brake operation means,
A vehicle speed control device having a parking brake that prevents erroneous running of a stopped vehicle,
When the accelerator and the brake operating means are off and the vehicle speed is slower than a predetermined speed, the control circuit operates the parking brake automatically after driving the brake motor to stop the vehicle. Vehicle speed control device.

Images