JPH0310941A - Fail-safe device for constant speed vehicle - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a fail-safe device for dealing with abnormalities in a constant-speed vehicle traveling system that maintains a constant vehicle speed.

<Prior art> This type of conventional constant speed traveling device detects the vehicle speed with a vehicle speed sensor, compares it with a target vehicle speed set by the driver's will, and sets a control amount according to the deviation. Based on 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 and realizing constant speed running.

<Problem to be Solved by the Invention> However, in such a constant speed traveling device for an automobile, dust becomes clogged between the piston and cylinder of the negative pressure actuator for driving the throttle valve, and the throttle valve is driven in the closing direction. There was a problem in that it was impossible to deal with abnormalities that would make it impossible to reduce the engine output.

The present invention has been made in view of such conventional problems, and it is possible to reduce the engine output independently of the constant speed driving control in the event of an abnormality in which the engine output of the constant speed driving device for automobiles cannot be reduced. The purpose of the present invention is to provide a fail-safe device.

<Means for Solving the Problems> Therefore, as shown in FIG. 1, the present invention includes a vehicle speed detecting means for detecting vehicle speed, a target vehicle speed setting means for setting a target vehicle speed according to the driver's will, and a detecting device. and a constant speed running control means for controlling engine output so that the determined vehicle speed coincides with a target vehicle speed, the engine control means j' is provided in an intake passage of the engine. An abnormality in which a normally open fail-safe throttle valve that is controlled to open and close independently of n is provided, and the vehicle speed detected during constant speed driving control by the constant speed driving control means continues to be larger than the target vehicle speed. The present invention is constructed by providing an abnormality detection means for detecting the abnormality, and a fail-safe control means for driving the fail-safe throttle valve in the closing direction when the abnormality is detected.

If a mechanical failure occurs in the drive means such as a negative pressure actuator and the throttle valve is held open, the actual vehicle speed detected by the vehicle speed detection means will be higher than the target vehicle speed. continues, the abnormality detection means detects this as an abnormality, and the failsafe control means drives the failsafe throttle valve in the closing direction.

This reduces engine output and allows the vehicle to stop smoothly.

<Example) Embodiments of the present invention will be described below based on the drawings.

In FIG. 2 showing the configuration of one embodiment, a throttle valve 2 is interposed in an intake passage 1 of an engine, and is connected to an accelerator pedal 3 via an accelerator link 4. It is also connected to a negative pressure actuator 5 constituting the driving means of the device. Further, a fuel injection valve 6 is installed in the intake passage 1 to inject and supply fuel.

The control pressure chamber 5b defined by the piston 5a of the negative pressure actuator 5 includes a vacuum valve 7 for introducing negative pressure from a negative pressure supply source that has accumulated a predetermined negative pressure, and an air valve 8 for introducing atmospheric pressure. and release pulp 9 are attached.

During automatic constant speed driving, the vacuum pulp 7 is closed, the air pulp 8 and the release valve 9 are opened, the inside of the negative pressure actuator 5 is set to atmospheric pressure, the negative pressure actuator 5 is deactivated, and the automatic constant speed driving is performed. When this happens, the release valve 9 closes, and the pressure applied to the negative pressure actuator 5 is controlled by opening and closing the vacuum valve 7 and air valve 8 to operate the throttle valve 2.

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

The control circuit 11 has a built-in microcomputer including a CPU, ROM, RAM, and Ilo.
Intake air flow rate Q detected by air flow meter 12, engine rotation speed N detected by crank angle sensor 13, and cooling water temperature T detected by water temperature sensor 14. In addition, the vehicle speed S from the vehicle speed sensor 15 as vehicle speed detection means, the throttle valve opening θ detected by the throttle sensor 16, the brake operation signal B detected by the brake switch 17, and the target vehicle speed from the operation panel 10. S, performs arithmetic processing while inputting a double signal to control the engine such as fuel injection 1 ignition timing, etc., and also controls the vacuum valve 7, air pulp 8, etc. to perform automatic constant speed driving control (therefore, the control circuit 11 .Vacuum valve 7, air valve 8, negative pressure actuator 5
constitutes constant speed running control means).

A fail-safe device according to the present invention that performs fail-safe operation in the event of an abnormality in the automatic constant speed cruise control device 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 to close by the DC motor 22 in response to a fail-safe signal from the control circuit 11, independently of the constant speed traveling control by the automatic constant speed traveling device.

In addition to the various controls described above, the control circuit 11 detects an abnormality in which the detected actual vehicle speed continues to be higher than the target vehicle speed during constant speed driving control, and outputs a fail-safe signal in that case. The fail-safe throttle valve 21
Perform fail-safe control to close. Incidentally, the fail-safe throttle valve 21 is kept fully open as shown in the figure except in the above-mentioned abnormality.

The failsafe control routine will be explained below according to the flowchart shown in FIG.

This routine is executed during automatic constant speed driving control.

In step 1 (denoted as S in the figure), a target vehicle speed S, which is set during automatic constant speed driving control, is input.

In step 2, the actual vehicle speed S detected by the vehicle speed sensor 11 is input.

In step 3, target vehicle speed Sm and actual vehicle speed Sl are compared.

If the actual vehicle speed S8 is greater than the target vehicle speed S, the process advances to step 4 and a timer is activated.

In step 5, it is determined whether the elapsed time measured by the timer has exceeded a predetermined value.

When the value exceeds the predetermined value, the process proceeds to step 6, where the DC motor 22 is driven and the normally open fail-safe throttle valve 21 is closed.

When it is determined in step 3 that the actual vehicle speed S+t is equal to or less than the target vehicle speed S, the routine proceeds to step 7, where the timer is cleared, this routine is ended, and automatic constant speed driving control is continued.

Even when the elapsed time is less than the predetermined value in step 5, this routine is ended and automatic constant speed driving control is continued.

If such control is performed, even if an abnormal situation occurs in which the sliding portion of the piston 5a of the negative pressure actuator 5 is clogged with dust and the throttle valve 2 is held open, the fail-safe throttle valve 21 will be closed. This makes it possible to reduce engine output and safely stop the vehicle.

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 detection means, and the functions of the DC motor 22 and step 6 constitute the fail-safe control means. Configure.

Note that the fail-safe throttle valve 21 may be fully closed immediately in the event of an abnormality, but may be closed continuously or in stages to alleviate deceleration shock. Further, when the target vehicle speed S is lower than the target vehicle speed S, by returning the throttle valve to the open direction, the fail-safe throttle valve 21 can be used as a fail-safe substitute for constant-speed traveling control.

In addition, in recent years, vehicles equipped with traction devices that detect wheel slippage and control the auxiliary throttle valve using an actuator, separate from the main throttle valve linked to the accelerator pedal, reduce engine output and suppress slippage. In this case, the auxiliary throttle valve can be used as a fail-safe throttle valve, and only a software-based fail-safe function needs to be added, resulting in a large cost advantage.

In addition, some automatic constant speed driving devices are equipped with diesel engines, and in that case, diesel engines do not have a throttle valve and perform automatic constant speed driving control by controlling the amount of fuel injection. Even in the event of an abnormality in the injection system or the like that causes the vehicle speed to continue to exceed the target vehicle speed S, the fail-safe device according to the present invention is applied to control the separately provided fail-safe throttle valve in the closing direction. can do.

<Effects of the Invention> As explained above, according to the present invention, when an abnormality is detected in the automatic constant speed driving system in which the function of reducing the engine output is lost and the vehicle speed continues to exceed the target vehicle speed, By closing the fail-safe throttle valve, the engine output can be reduced and the fail-safe function can be improved, such as being able to safely stop the vehicle.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of the present invention, and FIG. 2 is a block diagram showing the configuration of the present invention.
FIG. 3, which is a diagram showing the configuration of an embodiment of the present invention, is a flowchart showing fail-safe control according to the embodiment.

Claims (1)

[Claims] A vehicle speed detection means for detecting the vehicle speed, a target vehicle speed setting means for setting the target vehicle speed according to the driver's will, and a constant speed driving control means for controlling the engine output so that the detected vehicle speed matches the target vehicle speed. In the constant speed driving device for an automobile, a normally open fail-safe throttle valve is provided in the intake passage of the engine and is controlled to open and close independently of the engine control by the constant speed driving control means, and an abnormality detecting means for detecting an abnormality in which a vehicle speed detected during constant speed driving control by the driving control means continues to be higher than a target vehicle speed; and driving the fail-safe throttle valve in a closing direction when the abnormality is detected. 1. A fail-safe device for a constant speed vehicle for an automobile, comprising a fail-safe control means.