JPS624637A - Automatic car speed control device - Google Patents

Abstract

PURPOSE:To make it easy to change control constant, by furnishing a ROM to store a memory of a constant variable depending on the car feature, of the control constants, at the outside of the control member. CONSTITUTION:Outputs from a car speed sensor 1 and a command switch 2 are input to a microcomputer 6 in a control member through interfaces 4 and 5 in a controller 3 respectively. In this case, the car speed is controlled to keep constant by sending a command to an actuator 10 responding to the difference between the memorized car speed when the command switch 2 is operated, and the practical car speed. A control constant variable with the car feature in a control program is stored in an external ROM and transferred to a RAM in the microcomputer 6 of the control member. As a result, the control constant can be changed easily depending on a variation of car feature, by replacing only ROM 7.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) This invention relates to an automatic vehicle speed control device used to automatically control the traveling speed of a vehicle to a certain set speed. be.

(Prior Art) This type of automatic vehicle speed control device has various configurations, but some of them include a vehicle speed sensor that generates a signal proportional to the actual vehicle speed, and a command switch that generates a cruise command signal. and.

a vehicle speed storage unit that stores the vehicle speed when the command switch is operated; and an actuator that drives the throttle valve.
There is an automatic vehicle speed control device that includes a controller that sends a command to the actuator in response to the difference between the actual vehicle speed and the stored vehicle speed.

In this automatic vehicle speed control device, by operating a command switch, the vehicle speed at the time of the operation is stored, and the controller and actuator are operated to drive the throttle valve in accordance with the difference between the stored vehicle speed and the actual vehicle speed. The actual vehicle speed is set to the memorized vehicle speed and the vehicle travels at a constant speed, which is convenient for driving on expressways.

(Problems to be solved by the invention) However, in the conventional automatic vehicle speed control device shown in L,
The engine performance, reduction ratio, vehicle weight, etc. differ depending on the vehicle model in which it is installed, and the vehicle speed control program installed in the microcomputer, which is the control section, is basically a speed control program, so initialization of the heavy speed control program, K ( Control formula F=
(@α+6), by changing control constants such as gain and accelerator off, the effect of -V characteristics is dealt with.In mask-type microcomputers, the vehicle speed control program is written in at the time of manufacture. , there is a problem that it takes time to manufacture the microcomputer due to the change of the control constants stored in the read-only memory provided inside the microcomputer, and especially when it is in the commercialization stage, there is a problem that the start of production is delayed. there were.

Therefore, the present invention has been made by focusing on the above-mentioned conventional problems.By providing an external read-only memory that stores control constants that change depending on the characteristics of the vehicle, it is possible to easily change the control constants. The purpose of the present invention is to provide a vehicle speed control device that can control vehicle speed.

Structure of the Invention L] (Means for Solving the Problems) The structure of the present invention to achieve the object described in L includes a vehicle speed sensor that generates a signal proportional to the actual vehicle speed, and a command switch that generates a cruise command signal. a vehicle speed storage unit that stores the vehicle speed when the command switch is operated; an actuator that drives a throttle valve; and a control unit that sends commands to the actuator in response to the difference between the actual vehicle speed and the stored vehicle speed. In an automatic control device, a read-only device that stores outside the control unit a constant that changes depending on the characteristics of the vehicle among the control constants, and transfers the constant to a write-read memory of the control unit at any time according to a command from the control unit. It is equipped with memory.

(Example) Hereinafter, the present invention will be explained based on the drawings.

1 to 4 are diagrams showing m=embodiments of the present invention.

FIG. 1 is an explanatory diagram showing the circuit configuration of an automatic vehicle speed control device. In FIG. 1, 1 is a vehicle speed sensor that generates a signal proportional to the actual vehicle speed, and 2 is a command switch that generates a cruise command signal. The command switch 2 includes a set switch and a resume switch. Outputs from the vehicle speed sensor 1 and the command switch 2 are input to a microcomputer 6, which is a control section within the controller 3, via interfaces 4 and 5, respectively, within the controller 3. Inside the microcomputer 6, there is a vehicle speed memory section that stores the vehicle speed when the command switch 2 is operated, and a vehicle speed sensor 1.
control means for keeping the vehicle speed constant in response to the difference between the actual vehicle speed and the military speed recorded in the vehicle speed storage section; and a read-only memory (hereinafter referred to as FROMJ) disposed within the controller 3 and connected to the microcomputer 6. (hereinafter referred to as rRAMJ) has a reading means for transferring the control constants which are stored in the microcomputer 6 and are changed depending on the characteristics of the vehicle to a read/write memory (hereinafter referred to as rRAMJ) built in the microcomputer 6. .

Further, 10 is an actuator, and as shown in FIG. 2, this actuator 10 is equipped with a vent valve 11, a safety valve 12, and a vacuum valve 13. In addition to being open to the atmosphere, the vacuum valve 13
One end is connected to the intake manifold (negative pressure source). Further, the other end of each valve 11, 12. One end of a control wire 18 is connected to the side (left side in FIG. 2), and the other end of the control wire 18 is connected to a throttle valve shaft 19.

Furthermore, 21 is a vent valve switching section 22 which is located in the controller 3 and controls the vent valve 11 on and off according to the output from the microcomputer 6.
is also located in the controller 3 and turns on/off the vacuum valve 13 according to the output from the microcomputer 6.
Vacuum valve switching unit for off-control, 23
is an actuator switching unit that is located in the controller 3 and turns off and on the power supply to the actuator 10 according to the output from the microcomputer 6; Relay 2 consisting of switch 25b
5.

Further, 27 is a brake switch, 28 is a brake lamp, and a signal for canceling the system when the brake is operated is sent to the interface 2 of the controller 3.
The signal is inputted into the microcomputer 6 via 9.

Furthermore, 31 is a constant voltage circuit, 32 is a reset circuit, 33
is a power supply, 34 is a main switch for the control bag, and 35 is a cruise lamp.

Next, the operation of the automatic vehicle speed control device with such a configuration will be explained with reference to FIGS. 3 and 4. First,
To operate the vehicle speed automatic g# device, press main switch 3.
At this time, the vehicle speed sensor 1 generates a pulse proportional to the actual vehicle speed, and this pulse signal is input into the microcomputer 6 of the controller 3 and sampled within a certain period of time. In this state, the set switch of the command switch 2 sends a set signal at time tl shown in FIG. 4, and the set signal is released at time E2. At this point, a read control routine shown in FIG. 3 is started in which control constants are transferred from the ROM 7 to the RAM in the microcomputer 6 in accordance with automatic vehicle speed control.

First, in step 101, the leading address of the ROM 7 and the leading address of the RAM in the microcomputer 6 are set.

Then, in the next step 102, information corresponding to the address is set in the output port of the microcomputer 6, and in step 103, +111 is set corresponding to the output port of the microcomputer 6 according to the information of the output port of the microcomputer 6. An address is set to the input port of ROM7, and data corresponding to the set 7 traces appears at the output port of ROM7,
The input port of the microcomputer 6 reads the data that appears.

Furthermore, in step 104, the data already stored in the RAM in the microcomputer 6 is compared with the data read by the microcomputer 6 in step 103 to determine whether there is a difference in the data. If there is a difference (No), return to step 101 and read the data from the ROM 7 again. If there is no difference (YES), the process moves to the first step 105.

In this way, step 104 is provided to prevent the ILT electrical components, particularly the microcomputer 6, from being influenced by noise (ignition noise, radio interference, etc.) and erroneously transmitting data.

Then, in step 105, it is determined whether the data read into the microcomputer 6 is the same N times (N22), and if the read data is different even N times (No), it is determined that the transfer is an error. and then start over again from the first step 101, and step 105
If the read data is the same N times (N22) (YES), it is determined that the read data is accurate and the process moves to the next step 106.

In this way, step 105 generates noise (ignition noise) as in step 104.

This step is provided to prevent the in-vehicle electrical components, especially the microcomputer 6, from being adversely affected by erroneous data transfer due to radio wave interference, etc.
22) Also, the read data is compared with the RAM in the microcomputer 6 in step 104.
The data stored in the RAM and the data read into the microcomputer 6 are both determined to be the same due to the influence of noise, or the data stored in the RAM and the data read into the microcomputer 6 are determined to be the same.
While comparing the read data with the read data in step 104, it may be determined that they are the same due to the influence of noise. In this embodiment, +iiJ step 104
The reliability of the device is improved by comparing the data N times (N22) in step 105 to prevent erroneous transfer without directly transferring the data to the RAM.

Then, in step 106, the read data is transferred to the corresponding address of the RAM in the microcomputer 6, and in the next step 107, the transfer of all necessary data from the ROM 7 to the RAM in the microcomputer 6 is completed. If all the data has not been transferred (NO), in step 108, the ROM 7 and the RAM in the microcomputer 6 are transferred.
The address number is incremented by ~, and the process returns to step 102. Therefore, each step from step 102 to step 108 is to transfer data from the corresponding address in the ROM 7 to the corresponding address in the RAM in the microcomputer 6 for each address.

If all data transfer is completed (YES) in the step 107, the timer is reset to zero in the next step 109, and then automatic vehicle speed control is started in the next step 110.

As mentioned above, the time required for the control constants to be transferred from the ROM 7 to the RAM in the microcomputer 6 prior to automatic vehicle speed control, that is, the period from step 101 to step 110 of the read control routine, is extremely short. Therefore, the cruise lamp 35 is turned on at time t2 shown in FIG. 4 when the set signal is released without affecting the automatic vehicle speed control such as an operation delay, and the microcomputer 6 is activated according to the vehicle speed at that time. At the same time, the vent valve 11 and the safety valve 12 are closed to isolate the negative pressure chamber 17 from the atmosphere, and the vacuum valve 13 is opened to introduce negative pressure into the negative pressure chamber 17. death.

Slot valve shaft 19 via control wire 18
be held in place. After this, even if the accelerator pedal is released, the slot valve shaft 19 is held at a predetermined position, so that the vehicle can travel at a constant speed. After this, a command is sent to the actuator 10 so that the number of detected pulses proportional to the actual vehicle speed becomes equal to the number of pulses stored in E (that is, the stored vehicle speed).
Vent/< via the vent valve switching section 21 and vacuum valve switching section 22, respectively.
The negative pressure state in the negative pressure chamber 17 of the actuator 10 is controlled by turning on and off the valve 11 and the vacuum valve 13. For example, when the actual vehicle speed becomes smaller than the stored vehicle speed by a predetermined value, the microcomputer
By operating the vacuum valve switching unit 22 controlled by increase. On the other hand, when the actual vehicle speed becomes higher than the memorized vehicle speed by a predetermined value, the vent valve 11 is turned off by the operation of the vent valve switching section 21 controlled by the microcomputer 6, and atmospheric air is introduced into the negative pressure chamber 17. This causes the throttle valve shaft 19 to rotate slightly in the valve closing direction, thereby reducing the vehicle speed. By repeating this operation, the vehicle speed is controlled to be constant.

When the automatic vehicle speed control is started in step 110 in this way, in the next step 111, it is determined whether the timer reset to zero in step 109 has reached the set time or not. case (N
In step O), automatic vehicle speed control is continued in step 110.

Further, in step 111, if the timer reaches the set time (YES), the process returns to step 101 with the automatic vehicle speed control unchanged.

The control constants are transferred from the ROM 7 to the RAM in the microcomputer 6 again.

Although the RAM provided in the microcomputer 6 has a fast recall time, it cannot detect any malfunction due to noise or the like, so it is necessary to constantly update the memory contents. The control constants are transferred from ROM 7 to R in microcomputer 6 as described in
After the transfer to AM, step 109 of resetting the timer to zero and step 111 of determining whether the timer has reached the set time are provided.

Furthermore, the ROM 7 is a mask type ROM that is written in during manufacturing, a fuse type ROM that cannot be rewritten once written, and a UVPR that erases the memory contents with ultraviolet rays.
OM, EEFROM that can be rewritten with a dedicated writer (
Electrically Erasable Programmer-Pull ROM), EFRO
M etc.

Furthermore, when you want to reduce the vehicle speed when driving at a constant speed, if you keep pressing the set switch at time t3 shown in Figure 4, atmospheric air is introduced into the negative pressure chamber 17, the vehicle speed is reduced by engine braking, and the set switch is turned off. time t4
The vehicle speed at is memorized and the vehicle resumes constant speed driving. Then, at time t5 when the brake is operated, the system is canceled and the vehicle speed is reduced to the lower limit (for example, 40 to 50 km).
/hr), if the resume switch is operated at time t6, the vehicle resumes running at a constant speed at the speed before the brake operation, and if the resume switch is continued to be operated at 1 hour t7, the vehicle speed gradually increases, and when the resume switch is pressed. The vehicle speed at time t8 is memorized and the vehicle runs at a constant speed, and at time t9, the clutch is operated in the case of a manual transmission vehicle, or the torque converter lever position is set to neutral (N) or park (P) in the case of an automatic transmission vehicle. The system will be deactivated when

Note that in this embodiment, the actuator 1 that uses negative pressure
0, the slot valve shaft 1 is controlled by a command from the microcomputer 6.
A motor-driven actuator that drives 2 may also be used,
In particular, the actuator 10 is not limited to a negative pressure type.

[Effects of the Invention] As explained above, according to the present invention, there are provided a vehicle speed sensor that generates a signal proportional to the actual vehicle speed, a command switch that outputs a cruise command signal, and a vehicle speed memory that stores the vehicle speed when the command switch is operated. an actuator that drives a throttle valve; and a control section that sends a command to the actuator in response to a difference between an actual vehicle speed and a memorized vehicle speed;
Among the control constants, a read-only memory is provided that stores constants that vary depending on the characteristics of the vehicle, and that transfers the constants to the read/write memory of the control unit at any time according to commands from the control unit, so that the constants are stored in the control unit. By replacing the external read-only memory without changing the control program, it is possible to respond to changes in vehicle characteristics, and even just before the commercialization stage, control constants can be easily changed without the need for large-scale production equipment. The excellent effect of being able to do this can be obtained.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the circuit configuration of an automatic vehicle speed control device according to an embodiment of the present invention, Fig. 2 is an explanatory cross-sectional diagram of the actuator shown in Fig. 1, and Fig. 3 is an explanatory diagram showing the circuit configuration of an automatic vehicle speed control device according to an embodiment of the present invention. FIG. 4 is an explanatory diagram showing an example of a change in vehicle speed due to command switch operation. 1...Vehicle speed sensor. 2... Command switch, 6... Control unit (microcomputer), 7... Read-only memory (ROM). 10... Actuator, 12... Slot pulp shaft.

Claims (4)

[Claims] (1) a vehicle speed sensor that generates a signal proportional to the actual vehicle speed, a command switch that outputs a cruise command signal, and a vehicle speed storage unit that stores the vehicle speed when the command switch is operated;
In an automatic vehicle speed control device that includes an actuator that drives a throttle valve and a control section that sends a command to the actuator in response to a difference between an actual vehicle speed and a stored vehicle speed, the vehicle An automatic vehicle speed control device comprising: a read-only memory that stores constants that vary depending on the characteristics of the controller, and transfers the constants to a read/write memory of the controller at any time according to commands from the controller. (2) The automatic vehicle speed control device according to claim (1), wherein the transfer of control constants from the read-only memory to the read-out memory is updated at regular intervals. (3) Transfer of control constants from read-only memory,
The vehicle speed according to claim (1) or (2) is characterized in that if the data is the same N times after N times (N≧2), the data is transferred to the write/read memory at any time. Automatic control device. (4) Read-only memory includes mask-type read-only memory, EEP read-only memory, EP read-only memory, fuse-type read-only memory, and UV
Claim No. (1) which is P read-only memory
The automatic vehicle speed control device according to any one of items (3) to (3).