JPS62160924A - Constant speed travel device for automobile - Google Patents

Abstract

PURPOSE:To prevent a vehicle from running away even if a brake switch fails, by providing such an arrangement that when the lowering rate of rotational speed of an engine exceeds a predetermined value, the control of constant speed travel is released. CONSTITUTION:A constant speed travel detecting device 1 is constituted such that a controller compares an actual vehicle speed detected by a vehicle speed sensor 9 with a set vehicle speed, and therefore, controls the opening degree of a throttle valve to make both speeds coincide with each other. Accordingly, controls receives the rotational speed of an engine detected by an engine rotational speed sensor 30 so that the lowering rate dN/dt of the engine rotational speed is calculated. If it is determined that the lowering rate exceeds a predetermined value, the controller 5 deenergizes all solenoids 11a, 12a, 13a to release the control of the constant speed and therefore, the throttle valve is actuated by manipulating an accelerator pedal. Thus it is possible to release the control of constant speed travel by brake operation when the engine rotational speed lowers even if a brake switch fails.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a constant speed traveling device for an automobile that maintains the vehicle speed at a desired set value and causes the vehicle to travel at a constant speed.

(Prior Art) In recent years, constant speed traveling devices that automatically maintain the vehicle speed of an automobile at a desired speed set by a driver have been put into practical use. This constant speed traveling device sets the vehicle speed as a target value for constant speed traveling by a set operation by the driver when the vehicle speed reaches a desired vehicle speed, and thereafter compares this set vehicle speed with the actual vehicle speed. Therefore, when a difference occurs between the two, the throttle valve of the engine is controlled according to the difference, thereby making the actual vehicle speed match the set vehicle speed. An example of such a constant speed traveling device is disclosed in Japanese Utility Model Application No. 57-164228.

The constant speed driving device is operated by the driver while driving by operating a switch, etc., but after starting constant speed driving control by this operation, it is usually necessary to cancel this control. A switch is provided that operates simultaneously with the operation of the brake pedal, accelerator pedal, etc., and this switch is used to cancel constant speed running. In such a case, for example, if this switch malfunctions and constant speed driving is not canceled even when the brake pedal is pressed, the problem is that when the brake pedal is released, the vehicle will accelerate to the set speed again, which is dangerous for driving. There is.

For this reason, for example, Japanese Patent Application Laid-open No. 55-29016 discloses, in addition to a brake switch that operates with the operation of the brake pedal to cancel constant speed driving control, a brake switch that operates when the vehicle speed decreases beyond a predetermined value. A device for canceling constant speed running is disclosed.

If such a device is used, constant speed driving control can be canceled even if the brake switch fails, increasing driving safety. Therefore, if the vehicle speed does not decrease much even if the brake pedal is depressed, there is a problem in that the constant speed running is not canceled.

(Purpose of the Invention) The present invention was made in view of the above problem, and even if the brake switch for canceling the constant speed driving control fails, the constant speed control is immediately restored when the brake is operated. It is an object of the present invention to provide a constant speed traveling device for a motor vehicle that is capable of canceling traveling control.

(Configuration of the Invention) The configuration of the constant speed traveling device of the present invention will be explained based on the claim correspondence diagram of FIG. The constant speed traveling device of the present invention converts the actual vehicle speed detected by the vehicle speed detection means B1 into the vehicle speed control means B2.
The vehicle speed is compared with the set vehicle speed, and an activation signal is output from the vehicle speed control means B2 to the fuel supply means B3.
controls the amount of fuel supplied to the engine by opening and closing the throttle valve, etc., and maintains the actual vehicle speed approximately at the set vehicle speed.Meanwhile, the engine rotation detection means B4 detects changes in the engine rotation speed. The constant speed running system release means B5 determines whether the rate of decrease in engine rotation speed detected by the engine rotation detection means B4 is greater than a predetermined value, and if the rate of decrease is greater than the predetermined value, The present invention is characterized in that the constant speed driving control by the vehicle speed control means B2 is canceled by the speed driving system release means B5.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, the constant speed traveling device has a controller "15" connected via a main switch 4 to a power supply circuit 3 led from a power supply 1 via an ignition switch 2. Signals from an accelerator switch 6, a coast switch 7, and a resume switch 8 as vehicle speed setting means and a signal from a vehicle speed sensor 9 are inputted, and the actuator 10 is inputted from the controller 5.
A signal is output to the solenoids 11a, 12a, and 13a. Here, the controller 5 plays a role as a vehicle speed control means and a constant speed running system canceling means, and is composed of a microcomputer, and has various arithmetic processing units (CPLI) and a read-only memory (ROM) containing control programs. and a write-in memory (RAM) for temporarily storing various data.

The accelerator switch 6, the coast switch 7, and the resume switch 8 are connected between the controller 5 and the ground. Among these switches, the Adacel switch 6 also functions as a set switch, and is connected to the vehicle speed sensor 9. For example, the lotus indicated by the signal from
A vehicle speed setting function that sets the vehicle speed at that time as the set vehicle speed for constant speed driving by operating αN when the desired vehicle speed is reached within the range of 100 KIR/h;
By keeping the ON state □, the set vehicle speed is increased during this time, and when the vehicle is turned OFF, it has an acceleration function that causes the vehicle to travel at a constant speed at this increased vehicle speed. Further, the coast switch 7 is used to decelerate the vehicle while traveling at a constant speed, and when it is turned on, the set vehicle speed decreases. Further, when the constant speed driving control is canceled due to a reason other than the OFF operation of the main switch 4, the resume switch 8 is turned ON to return the vehicle to the set vehicle speed before the cancellation. Then, the solenoid 11a of the actuator 10 is activated from the controller 5 based on the signals from the operation of these switches 6, 7, and 8 and the signal from the vehicle speed sensor 9.

Actuation signals are output to 12a and 13a to maintain, accelerate, decelerate, or restore the vehicle speed.

Further, in this constant speed traveling device, a clutch switch 14 as a constant speed traveling canceling means for canceling constant speed traveling control and a brake switch 15 are arranged in parallel between the power supply circuit 3 and the controller 5. These switches 14 and 15 are turned ON when the clutch is disengaged and when the brake is applied, respectively, to input a release signal to the controller 5 and cause the controller 5 to release the constant speed running control.

Further, an engine rotation sensor 30 that detects the engine rotation speed is also connected to the controller 5, and the rate of decrease in the engine rotation speed is determined based on the engine rotation speed information sent from this sensor 30 to the controller 5. It is determined whether or not this rate of decrease is greater than or equal to a predetermined value, and when it is greater than or equal to the predetermined value, the controller 5 acts as a constant speed driving system canceling means and cancels the constant speed driving control.

Next, to explain the structure of the actuator 10, as shown in FIG. 2, the actuator 10 is a negative pressure diaphragm type actuator, and the inside of the casing 16 is airtight from the outside by a rubber diaphragm 17. The diaphragm 17 is defined into a negative pressure chamber 18 and an atmospheric chamber 20 communicated with the outside through a through hole 19.
is biased toward the atmospheric chamber 20 by a spring 21 disposed in the negative pressure chamber 18, and a negative pressure introducing tlenoid valve 11 is provided on the end face of the casing 16 to control the introduction of negative pressure into the negative pressure chamber 18. and 1st. The structure includes second atmosphere introduction solenoid valves 12 and 13 (the second atmosphere introduction solenoid valve 13 is not shown). The rod 2 connected to the diaphragm 17
2 is slidably held by a bearing part 23 provided in the casing 16 and protrudes outward through the atmospheric chamber 20, and is provided in the intake passage of the engine via a wire 24. connected to the throttle valve 25;
The throttle valve 25 is operated in the opening direction when the diaphragm 17 moves in the A direction (towards the negative pressure chamber 18).

Further, the negative pressure introduction solenoid valve 11 opens a passage 11b, which has one end connected to a negative pressure introduction pipe 26 led from a negative pressure source and the other end communicates with the inside of the negative pressure chamber 18, with the valve body 11c. The valve body 11c is pressed and biased by a spring 11d to shut off the passage 11b, and also opens the passage 11b against the spring 11d when the solenoid 11a is energized. will be moved to Similarly, the first atmosphere introduction solenoid valve 12 (the same applies to the second atmosphere introduction solenoid valve 13) has a passage 12b that is open to the atmosphere at one end and communicated with the negative pressure chamber 18 at the other end. 12c opens and closes the passage, and the valve body 12c is connected to the passage 1 by a spring 12d.
2b is tensilely biased to open,
When the solenoid 12a is energized, the passage 12b is blocked against the spring 12d. and,
The negative pressure in the negative pressure chamber 18 of the actuator 10 is controlled by energizing the solenoids 11a, 12a, and 13a of these solenoid valves 11, 12, and 13 using signals from the controller 5 shown in FIG. At the same time, the diaphragm 17
The opening degree of the throttle valve 25 is controlled by the displacement of the throttle valve 25.

Next, the specific operation of the above-mentioned actuator will be explained.

For example, the vehicle speed during normal driving is 40 to 100 KIR.
/h, when the accelerator switch 6 connected to the control device 5 of the constant speed traveling device is turned on, the vehicle speed at that time indicated by the signal from the vehicle speed sensor 9 is set in the controller 5 as the set vehicle speed. Thereafter, the controller 5 outputs a signal to the actuator 10 to match the actual vehicle speed with the set vehicle speed while comparing the set vehicle speed with the actual vehicle speed indicated by the signal from the vehicle speed sensor 9.

That is, when the actual vehicle speed becomes lower than the set vehicle speed, the controller 5 outputs an energization signal to the solenoids 11a and 12a of the negative pressure introduction solenoid valve 11 and the atmosphere introduction solenoid valve 12 in the actuator 10, and the negative pressure introduction solenoid valve 11 opens, and the first atmosphere introduction solenoid valve 12 closes. Therefore, negative pressure is introduced into the negative pressure chamber 18 of the actuator 10, displacing the diaphragm 17 in the A direction, and accordingly, the throttle valve 25 is operated in the opening direction via the rod 22 and wire 24, and the engine is The amount of fuel supplied will increase. As a result, the actual vehicle speed increases and becomes equal to the set vehicle speed.

On the other hand, when the actual vehicle speed is higher than the set vehicle speed, the solenoids 11a and 12a are not energized, so that the negative pressure introduction solenoid valve 11 is closed and the first atmosphere introduction solenoid valve 12 is opened, so that the negative pressure The negative pressure within chamber 18 is reduced. Therefore, the diaphragm 17 is displaced in the anti-A direction, the throttle valve 25 is operated in the closing direction, and the amount of fuel supplied to the engine is reduced, thereby reducing the actual vehicle speed to match the set vehicle speed. In addition, during such constant speed running control, the solenoid 13a of the second atmosphere introduction solenoid valve 13 is always energized.
The valve 13 is kept closed. Furthermore, when the clutch switch 14 or the brake switch 15, which serves as a means for canceling the constant-speed running control, is turned on, the energization to the solenoids 11a, 12a, and 13a is all stopped.
The negative pressure introducing solenoid valve 11 is closed, and the first solenoid valve 11 is closed. When the second atmosphere introduction solenoid valve 12.13 opens and the inside of the negative pressure chamber 18 is released to the atmosphere, the operation of the actuator 10 is completely stopped, and the engine throttle valve 25 is completely stopped.
is activated by operating the accelerator pedal.

Further, when it is determined that the rate of decrease in the engine speed detected by the engine speed sensor 30 is equal to or higher than a predetermined value, the controller 5 causes each of the solenoids 11a to
, 12a, and 13a are all stopped, constant speed driving control is canceled, and the throttle valve 25 is operated in response to the operation of the accelerator pedal.

The details of control by the controller 5 in the constant speed traveling device described above will be explained with reference to the flowchart of FIG. 4.

In this control starting from step S1, constant speed running control is first performed in step S2.

As mentioned above, this constant speed driving control compares the set vehicle speed and the actual vehicle speed, and increases the throttle valve opening if the actual vehicle speed is lower than the set vehicle speed, and conversely, if the actual vehicle speed is higher than the set vehicle speed. First, the actuator is controlled to reduce the opening degree of the throttle valve so that the actual vehicle speed approximately matches the set vehicle speed. Next, in step S3, the engine rotation speed is detected by the engine rotation' sensor 30. After that, in step S4, the engine speed reduction rate dN/dt is calculated, and this reduction rate dN
It is determined whether /dt is larger than a predetermined value. dN/
When dt≦, the process returns to step S2 and continues constant speed driving. On the other hand, when dN/dt>K, the process proceeds to step S5 to cancel the constant speed driving control, and then proceeds to step S6. This flow ends with . Note that this control does not detect the rate of decrease in vehicle speed, but instead detects the rate of decrease in engine rotation, which has a relatively large change, so it is easy to determine whether the rate of decrease exceeds a predetermined value. . In addition, since the system detects the rate of decrease rather than the amount of decrease, immediately after the engine speed starts decreasing due to brake operation, it is determined whether or not it is necessary to cancel constant speed driving, and then cancels constant speed driving control. can be set.

(Effects of the Invention) As explained above, according to the present invention, in a constant speed traveling device that controls the amount of fuel supplied to the engine to perform constant speed traveling, when the rate of decrease in engine rotation exceeds a predetermined value. Even if the brake switch fails and the brake pedal is pressed, the constant speed cruise control release signal will not be output from the brake switch. Also, when the engine speed decreases due to brake operation, the constant speed running control can be canceled immediately, and it is possible to prevent the vehicle from running out of control due to a brake switch failure.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of a constant speed traveling device according to the present invention, Fig. 2 is a sectional view of an actuator in the device, Fig. 3 is a block diagram showing the configuration of the device, and Fig. 4 is a constant speed driving device by the device. It is a flowchart which shows the content of travel control. 5... Controller 6... Accelerator switch 7... Coast switch 8... Resume switch 10... Actuator 25... Throttle valve 30... Engine rotation sensor Fig. 1 Fig. 2 Fig. 3 Figure 4

Claims (1)

[Scope of Claims] A vehicle speed detection means for detecting the actual vehicle speed; a fuel supply means for controlling the amount of fuel supplied to the engine; and a comparison between the actual vehicle speed detected by the vehicle speed detection means and a preset vehicle speed. a vehicle speed control means for controlling the operation of the fuel supply means so as to maintain the actual vehicle speed approximately at the set vehicle speed and drive the vehicle at a constant speed; and an engine rotation detection means for detecting a change in the rotation speed of the engine. The vehicle is characterized by comprising constant speed driving system canceling means for canceling constant speed driving control by the vehicle speed control means when the rate of decrease in engine speed detected by the engine rotation detecting means is greater than a predetermined rate of decrease. Constant speed running device for automobiles.