JP4151883B2 - Vehicle speed control device - Google Patents

Description

[0001]
BACKGROUND 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 the accelerator and the brake. In a vehicle such as a golf cart, a brake motor for automatically applying the brake is provided separately from the brake pedal in order to enable automatic driving. The vehicle includes a control circuit (CPU) that controls driving of a vehicle drive source (for example, an engine). The CPU drives the brake motor based on the indicated vehicle speed that limits the maximum speed during normal travel. As a result, the vehicle speed is limited and the maximum speed is set to a certain constant speed (indicated vehicle speed) to ensure safety.
[0003]
On the other hand, the vehicle is provided with an electromagnetic brake (parking brake) in addition to such a brake for controlling the vehicle speed to prevent the vehicle from erroneously running after the vehicle stops and the driver gets off.
[0004]
[Problems to be solved by the invention]
However, in a vehicle such as a golf cart having the conventional vehicle speed control device, it may be felt that the speed is too high on a steep downhill or the like even if the maximum speed is limited by the indicated vehicle speed. Further, 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 a driven axle. Since this CVT is a belt type and the engine brake is not easily applied, when the vehicle goes down a steep slope, it is easy to increase the speed and it is difficult to control the vehicle speed appropriately.
[0005]
In addition, parking brakes that prevent the vehicle from running incorrectly, for example in the case of a golf cart, may not apply the parking brake with certainty in a hurry, and if the vehicle is stopped on a slope, the vehicle will continue to run. There was a risk. Conventionally, an automatic parking brake has 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 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 Regardless of this, the automatic parking brake was not activated, and there was a risk that the vehicle would continue to run if the vehicle was stopped on a slope.
[0006]
The present invention takes the above-described prior art into consideration, and an object thereof is to provide a vehicle speed control device that can travel at an appropriate slow speed even when going down a steep slope.
[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 for the drive source, a sensor for output control parameters of a drive source connected to an accelerator operated by a driver, In the vehicle speed control device comprising a vehicle speed sensor for detecting the speed of the vehicle and a control circuit for automatically operating the drive source and the brake based on the commanded vehicle speed, the control circuit keeps the maximum speed of the vehicle constant during normal travel. The brake is controlled based on the first command vehicle speed limited to the speed, the average braking force is greater than or equal to the set value A, the throttle opening is less than the set value B, and the average engine speed is less than the set value C. and controls the brake speed limit than that in place of the first instruction speed in a certain time is based on the slow second indication vehicle speed, when the setting condition is not met, in accordance with the operation state of the accelerator, If Kuseruofu based on the second instruction speed based on the first instruction speed if the accelerator partial, provides a vehicle speed control device and controls the brake on the basis of the first instruction speed if the accelerator fully open .
[0008]
According to this configuration, the braking force corresponding to the inclination in advance according to the inclination of the downhill or the like on which the vehicle travels, and the output control parameter of the drive source (for example, the throttle opening of the engine or the electric motor) In order to change the command vehicle speed that limits the maximum speed from the first command vehicle speed to a second command vehicle speed that is slower than the first command vehicle speed when the set condition is satisfied. You can drive with peace of mind at an appropriate slow speed on the slope.
[0012]
According to the present invention , the accelerator operating state is determined when the setting condition for switching from the first indicated vehicle speed to the second indicated vehicle speed is not satisfied, and if the accelerator is off, it is determined that there is an intention to decelerate. Switch to the indicated vehicle speed to reduce the speed limit. Thereby, the effect of an engine brake is substantially acquired.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic block diagram of a vehicle speed control apparatus 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 these operation amounts by a driver are input to a CPU (control circuit) 3 mounted on the vehicle. The engine 9 includes a carburetor 11 and a throttle opening sensor 8 that detects the opening of a throttle valve (not shown). The engine 9 is provided with an engine speed sensor 12. 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 belt type automatic transmission 13 to drive the rear wheels 14. Vehicle speed sensors 4 and 5 are provided in the transmission 6, and vehicle speed detection data is input to the CPU. The transmission 6 is provided with a parking brake 10 including an electromagnetic brake.
[0016]
The brake pedal 2 is connected to the brake drive mechanism 15 and operates the drum brake 18 of the front wheel 17 and the drum brake 19 of the rear wheel 14 via the wire 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 the depression amount of the accelerator pedal 1, and a depression amount detection sensor (not shown) of the brake pedal 2. Based on these detection signals, the throttle valve and brake motor 20 of the carburetor 11 are driven and controlled to control the vehicle speed.
[0017]
FIG. 2 is a flowchart showing vehicle speed control which is a reference of the present invention.
The vehicle travels with a maximum speed limited to a predetermined speed (first instruction vehicle speed) (step S1). The first indicated 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) automatically decelerates downhill whether the average braking force is greater than or equal to 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 S2). The determination of the engine speed is a conditional expression provided for erroneously recognizing that the vehicle exceeds the first command vehicle speed after starting acceleration only by determining the average braking force and the throttle opening described above. Instead of the engine speed condition, it is also possible to make a determination by using another means such as measuring the time after starting with a timer. The average braking force is a force value corresponding to the 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 inclination when the vehicle goes down the slope are measured and input in advance.
[0018]
When all of the above conditions are satisfied, it is determined that the vehicle is going down a slope, and the maximum speed is set to the second indicated vehicle speed that is slower than the first indicated vehicle speed (step S3). As a result, the brake motor driver 7 (FIG. 1) drives the brake motor 20 (FIG. 1) to further apply braking force to the vehicle. You can drive safely at a slow speed. If any one of the parameters for the downhill automatic deceleration determination is not applicable, the first command vehicle speed remains unchanged (step S4).
[0019]
When the vehicle speed is the second command vehicle speed, the CPU 3 (FIG. 1) determines whether to release the automatic downhill deceleration by determining whether the average braking force is less than the set value D and whether the average engine speed is greater than the set value E (step S5). If this condition is not satisfied, the CPU further determines whether the throttle opening is above the set value F and the predetermined time has passed with the throttle opening being exceeded (step S6). If this is not the case, it is determined that the vehicle is still down the slope, and the second indicated vehicle speed is maintained (step S7). If even one of the conditions in steps S5 and S6 is true, the vehicle is judged to have descended the hill and returned to the first command vehicle speed (step S8). As the set values D, E, and F, values corresponding to the inclination when the vehicle goes down a slope with a small inclination are measured and input in advance.
[0020]
In this way, by changing the indicated vehicle speed at the time of a steep slope and a gentle slope or when descending, it is possible to give an appropriate indicated vehicle speed according to the running state of the vehicle, and to travel safely at an appropriate slow speed In addition, it is possible to control the vehicle speed by detecting the inclination using a CPU provided in the 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 can also be applied 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. The throttle opening for controlling the output of the drive source is determined by replacing it with the motor current.
[0021]
FIG. 3 is a flowchart showing the vehicle speed control of the present invention.
The vehicle travels at the first indicated vehicle speed (step T1). During traveling, the CPU 3 (FIG. 1) automatically decelerates downhill whether the average braking force is greater than or equal to 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 when all the conditions are satisfied, the second indicated vehicle speed is set (step T3). If even one of these conditions is not satisfied, the CPU determines the accelerator work (depressed amount of the accelerator pedal) (step T4). If the driver does not step on the accelerator, that is, the accelerator is off, for example, even if it is determined that the vehicle is not driving downhill in step T2, it is determined that the driver does not want to speed up, and the second indicated vehicle speed is set. The motor driver 7 (FIG. 1) is actuated to brake the running of the vehicle (step T5). As a result, when the accelerator is off, the maximum speed is always limited to the second command vehicle speed, so that the effect of engine braking is substantially obtained, and vehicle speed control appropriately corresponding to the driver's intention can be performed.
[0022]
When the driver depresses the accelerator delicately, that is, in the case of the accelerator partial, the command vehicle speed is not changed, and the vehicle is driven at a speed corresponding to the accelerator operation amount within the range of the first command vehicle speed (step T6). When the driver steps on the accelerator fully open, the first command vehicle speed is maintained (step T7). Thus, regardless of whether the vehicle is traveling downhill, 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 automatic operation control of the parking brake .
While the vehicle is traveling (step U1), the CPU 3 (FIG. 1) determines whether the current vehicle speed (actual vehicle speed) of the vehicle is less than a predetermined speed G, the accelerator is off, and the operation of the brake pedal is off. . If any one of these conditions is not satisfied, the traveling is continued (step U3). When all of these conditions are satisfied, the driver decides that the driver has an intention to stop or that the vehicle has surely got off without stopping, and the brake motor 20 (FIG. 1) is operated to brake the vehicle (step U4). (Step U5). As the predetermined speed G, a low speed value is set such that the vehicle is about to stop. After this, the CPU automatically turns on the electromagnetic brake (parking brake) to reliably stop the vehicle. As a result, the vehicle can be reliably stopped, so that the vehicle does not travel erroneously on a slope or the like.
In other words, if the accelerator and brake pedal are off at a predetermined low speed or less, it is determined that the passenger has already got off, 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.
[0024]
【The invention's effect】
As described above, according to the present invention, according to the inclination of the downhill or the like on which the vehicle travels, this inclination is preliminarily determined as the brake braking force corresponding to the inclination and the engine speed (or motor speed). In order to change the command vehicle speed for limiting the maximum speed from the first command vehicle speed to the second command vehicle speed that is slower than this, it is determined based on the setting condition of the throttle opening (or motor current value). On a downhill, you can drive with a sense of security at an appropriate slow speed.
[0026]
Further, when the setting condition for switching from the first command vehicle speed to the second command vehicle speed is not satisfied, the accelerator operation state is determined, and if the accelerator is off, it is determined that there is an intention to decelerate and the control is switched to the second command vehicle speed. Reduce the speed. Thereby, the effect of an engine brake is substantially acquired.
[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 which is a reference of the present invention.
FIG. 3 is a flowchart showing a vehicle speed control of the present invention.
FIG. 4 is a flowchart of automatic operation control of a parking brake .
[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: carburetor, 12: rotational 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 (1)

A drive source for driving the vehicle;
A rotational speed sensor of the drive source;
An output control parameter sensor of a drive source connected to an accelerator operated by a driver;
A vehicle speed sensor for detecting the speed of the vehicle;
In a vehicle speed control device comprising a control circuit for automatically operating a drive source and a brake based on an instructed vehicle speed,
The control circuit controls the brake on the basis of a first command vehicle speed that limits the maximum speed of the vehicle to a constant speed during normal travel, the average braking force is equal to or greater than a set value A, and the throttle opening is set to a set value B. And when the average engine speed is less than the set value C, the brake is controlled based on the second command vehicle speed, which is slower than the first command vehicle speed and the speed limit is slower than the first command vehicle speed ,
When the set condition is not satisfied, depending on the operation state of the accelerator, if the accelerator is off, it is based on the second indicated vehicle speed, if the accelerator is partial, it is based on the first indicated vehicle speed, and if the accelerator is fully open, the first indicated vehicle speed is set. A vehicle speed control device that controls a brake based on the vehicle.

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