JP2759501B2 - Fail-safe equipment for constant-speed traveling equipment for automobiles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a fail-safe device for coping with an abnormality of a constant-speed traveling device for a vehicle that maintains a constant vehicle speed.

<Conventional technology> This kind of conventional constant-speed traveling device detects a vehicle speed with a vehicle speed sensor, compares the detected vehicle speed with a target vehicle speed set by a driver's will, and sets a control amount according to a deviation, On the basis of this, a driving means such as a negative pressure actuator is driven to adjust the throttle valve opening of the engine, thereby controlling the engine output to realize constant speed traveling.

<Problems to be Solved by the Invention> However, in such a constant speed traveling apparatus for an automobile, dust is clogged between a piston and a cylinder of a negative pressure actuator for driving a throttle valve, and the throttle valve is driven in a closing direction. There is a problem that it is not possible to cope with abnormalities that make it impossible to lower the engine output.

The present invention has been made in view of such a conventional problem, and in the event of an abnormality that makes it impossible to reduce the engine output of the constant-speed traveling device for an automobile, the engine output can be reduced independently of the constant-speed traveling control. It is an object of the present invention to provide a fail-safe device as described above.

<Means for Solving the Problems> As shown in FIG. 1, the present invention provides a vehicle speed detecting means for detecting a vehicle speed, a target vehicle speed setting means for setting a target vehicle speed in accordance with a driver's will, Speed control device for controlling the engine output by controlling the opening of a throttle valve interposed in the intake passage of the engine so that the vehicle speed matches the target vehicle speed. In the engine, a normally-open fail-safe throttle valve that is opened and closed independently of the engine control by the constant-speed traveling control means is provided in the intake passage of the engine, and the throttle valve for the constant-speed traveling control is opened. The state in which the vehicle speed detected during the constant-speed traveling control by the constant-speed traveling control means is higher than the target vehicle speed continues for longer than a set time so that the abnormality can be detected. Abnormality detection means for detecting the occurrence of the abnormality, and fail-safe control means for driving the fail-safe throttle valve in the closing direction when the abnormality is detected.

<Operation> When a mechanical failure occurs in the driving means such as the negative pressure actuator and the throttle valve is held open, the actual vehicle speed detected by the vehicle speed detecting means becomes higher than the target vehicle speed. Is continued, the abnormality is detected by the abnormality detecting means, and when the above-mentioned state continues for a time set so that the abnormality can be detected in advance, an abnormality has occurred such that the throttle valve is kept open. And the fail-safe control means drives the fail-safe throttle valve in the closing direction.

As a result, the engine output is reduced and the vehicle can be stopped smoothly.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings.

2, a throttle valve 2 is interposed in an intake passage 1 of an engine, is connected to an accelerator pedal 3 via an accelerator link 4, and has a constant speed running for an automobile. It is also connected to a negative pressure actuator 5 which constitutes the driving means of the device. Further, a fuel injection valve 6 for injecting and supplying fuel is mounted in the intake passage 1.

The control pressure chamber 5b defined by the piston 5a of the negative pressure actuator 5 has a vacuum valve 7 for guiding a negative pressure from a negative pressure supply source storing a predetermined negative pressure, and an air valve 8 for guiding the atmospheric pressure. And a release valve 9 are mounted.

When the vehicle is not traveling at a constant speed, the vacuum valve 7
Is closed, the air valve 8 and the release valve 9 open,
When the inside of the negative pressure actuator 5 is set to the atmospheric pressure and the negative pressure actuator 5 is deactivated, the release valve 9 is closed at the time of automatic constant speed running, and the pressure applied to the negative pressure actuator 5 is controlled by opening and closing the vacuum valve 7 and the air valve 8. The throttle valve 2 is operated.

Reference numeral 10 denotes an operation panel, which includes a set switch, a reset switch, an accelerate switch, a cancel switch, and the like, is set and operated by a driver, and gives a target vehicle speed set by the driver to the control circuit 11. That is, the operation panel 10 constitutes a target vehicle speed setting means.

The control circuit 11 has a built-in microcomputer including a CPU, ROM, RAM, and I / O, and has an intake air flow rate Q detected by an air flow meter 12 and an engine rotation detected by a crank angle sensor 13. Number N, water temperature sensor 14
In addition to the cooling water temperature T _W detected by the vehicle speed S _R from the vehicle speed sensor 15 as a vehicle speed detecting means, the throttle sensor 16
The arithmetic processing is performed while inputting the throttle valve opening θ detected by the above, the brake operation signal B detected by the brake switch 17, and the target vehicle speed _Sa signal from the operation panel 10, and performs the fuel injection, ignition timing, etc. While controlling the engine, the vacuum valve 7 and the air valve 8 are controlled to perform automatic constant speed traveling control (therefore, the control circuit 1).
1, the vacuum valve 7, the air valve 8, and the negative pressure actuator 5 constitute a constant speed traveling control means).

A fail-safe device according to the present invention for performing fail-safe when the automatic constant-speed traveling control device is abnormal is provided as follows.

That is, a fail-safe throttle valve 21 is provided upstream of the throttle valve 2 in the intake passage 1, and the throttle valve 21 is controlled by the fail-safe control circuit 11 independently of the constant-speed traveling control by the automatic constant-speed traveling device. DC motor 22 by signal
To control the closing.

The control circuit 11, apart from the various controls, detects an abnormality in which the throttle valve for the constant-speed traveling control is kept open during the constant-speed traveling control, and determines whether the vehicle speed detected during the constant-speed traveling control is the target vehicle speed. Is detected by detecting that the abnormality has continued for a set time or more so that the abnormality can be detected.In that case, a fail-safe signal is output and the fail-safe throttle valve 21 is Perform fail-safe control to close. It should be noted that the fail-safe throttle valve 21 is kept fully open as shown in FIG.

Hereinafter, the fail-safe control routine will be described with reference to the flowchart shown in FIG. This routine is executed during the automatic cruise control. Step (abbreviated as S in the figure) in 1, and inputs the target vehicle speed S _a set during the automatic cruise control.

In step 2, and inputs the actual vehicle speed S _R detected by the vehicle speed sensor 11.

In step 3, is compared with the target vehicle speed S _a and the actual vehicle speed S _R.

When the actual vehicle speed S _R is larger than the target vehicle speed S _a, the process proceeds to step 4, to start the timer.

In step 5, it is determined whether the elapsed time measured by the timer is equal to or greater than a predetermined value.

If the value is equal to or more than the predetermined value, the process proceeds to step 6 where the DC motor 22 is driven to activate the normally open fail-safe throttle valve 21.
Close.

When the actual vehicle speed S _R is less than or equal to the target vehicle speed S _a in step 3, was clear the timer proceeds to step 7,
This routine ends, and the automatic constant-speed running control is continued.

If the elapsed time is less than the predetermined value in step 5, this routine is terminated and the automatic constant speed traveling control is continued.

By performing such control, even if an abnormal situation occurs in which the dust slides on the sliding portion of the piston 5a of the negative pressure actuator 5 and the throttle valve 2 is kept open, the fail-safe throttle valve 21 is closed. Therefore, the engine output can be reduced and the vehicle can be safely stopped.

In this embodiment, the functions of steps 1 to 5 of the fail-safe control routine shown in FIG. 3 by the control circuit 11 constitute the abnormality detecting means, and the DC motor 22 and the function of step 6 constitute the fail-safe control means. Configure.

The fail-safe throttle valve 21 may be fully closed immediately when an abnormality occurs, but may be closed continuously or stepwise to reduce a deceleration shock.
It is also possible to substitute the constant speed running control in fail-safe throttle valve 21 to the fail-safe manner by returning the opening direction when below the target vehicle speed S _a.

In recent years, there has been provided a traction device which detects a slip state of a wheel and controls the throttle of an auxiliary throttle valve separately from a main throttle valve linked to an accelerator pedal by an actuator, thereby lowering engine output and suppressing slip. In this case, the auxiliary throttle valve may be used as a fail-safe throttle valve, and only the fail-safe function by software needs to be added.

<Effect of the Invention> As described above, according to the present invention, in the automatic constant-speed traveling device, the abnormality in which the throttle valve for the constant-speed traveling control is held in the open state is detected when the vehicle speed detected during the constant-speed traveling control Is detected by detecting that the state where is larger than the target vehicle speed has continued for a time set to allow the abnormality to be detected, and by closing the fail-safe throttle valve, the engine output is reduced. And the fail-safe function such as stopping safely can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of the present invention, and FIG.
FIG. 3 is a flowchart showing the configuration of an embodiment of the present invention, and FIG. 3 is a flowchart showing fail-safe control according to the embodiment. 2 ... Throttle valve, 5 ... Negative pressure actuator, 7 ...
... Vacuum valve, 8 ... Air valve, 9 ... Release valve, 10 ... Operation panel, 11 ... Control circuit, 15 ...
Vehicle speed sensor, 21 ... Throttle valve for fail-safe, 22
…… DC motor

Claims (1)

(57) [Claims] 1. A vehicle speed detecting means for detecting a vehicle speed, a target vehicle speed setting means for setting a target vehicle speed in accordance with a driver's intention, and an engine intake passage so as to match the detected vehicle speed with the target vehicle speed. And a constant-speed traveling control device for controlling an engine output by controlling an opening degree of a mounted throttle valve. An engine control by the constant-speed traveling control device in an intake passage of an engine. A normally-open fail-safe throttle valve, which is opened and closed independently of the control, is provided. The constant-speed running control means detects the abnormality in which the throttle valve for the constant-speed running control is kept open. Abnormality detection that is detected by detecting that the state in which the vehicle speed detected at the time of control is higher than the target vehicle speed has continued for a time set to enable the abnormality to be detected. Stage and the fail-safe device for an automobile constant speed running device for the abnormality detection time of the fail-safe throttle valve and fail-safe control means for driving the closing direction, characterized by being configured to provide a.