JPH072997Y2 - Auxiliary air control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an auxiliary air control device for controlling the amount of auxiliary air in an auxiliary air passage that bypasses a throttle valve.

<Prior Art> The following is a conventional example of this type of auxiliary air control device (see Japanese Patent Application No. 62-035259).

That is, an auxiliary air control valve that controls the amount of auxiliary air is provided in the auxiliary air passage that bypasses the throttle valve.

Then, when the throttle valve is fully closed during deceleration operation, the control of the auxiliary air control valve is started based on the duty signal corresponding to the rotational speed at the time of full closing so as to suppress excessive rise in intake negative pressure. ing. Then, after that, the auxiliary air amount is feedback-controlled so that the engine speed is maintained at the target idle speed.

Further, there is one equipped with a so-called self-diagnosis device that detects and alarms an abnormality in the control system during idle operation (see Japanese Patent Laid-Open No. 61-49148).

Specifically, although the feedback correction value of the duty ratio of the auxiliary air control valve is held in the normal range, when the actual engine speed does not match the target idle speed, there is an abnormality in the control system. Making a decision. Then, when it is determined that there is an abnormality, in order to fully close the auxiliary air control valve, a fully closed command signal is issued to the fully closed relay connected in series to the drive solenoid of the auxiliary air control valve to turn off the fully closed relay. ing.

<Problems to be Solved by the Invention> However, in such a conventional auxiliary air control device, even when the auxiliary air control valve is locked to the fully open side due to a failure or the like, even if the control device issues a fully closed command signal. Since the auxiliary air control valve was not fully closed, the amount of auxiliary air did not decrease and the engine could run out of control.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an auxiliary air control device for an internal combustion engine that can prevent engine runaway even if the auxiliary air control valve is locked at the fully open side due to a failure. And

<Means for Solving Problems> Therefore, according to the present invention, as shown in FIG. 1, an auxiliary air control valve C controls the amount of auxiliary air in the auxiliary air passage B bypassing the throttle valve A. In an internal combustion engine equipped with a device D, an abnormality detecting means E for detecting an abnormality of the auxiliary air control device D, a rotation speed detecting means F for detecting an engine speed, and the auxiliary air control when the abnormality is detected. Full-close command signal output means G for outputting a full-close command signal to fully close the valve C, and timing means H for starting timing from the start of the abnormality detection or the start of the full-close command signal output.
And a fuel supply stopping means I for stopping the fuel supply to the engine when an abnormality continues to be detected and the engine speed is equal to or higher than a predetermined value after a lapse of a predetermined time from the start of timing.

<Operation> In this way, when an abnormality is detected, a fully-closed command signal is output to fully close the auxiliary air control valve, and when the abnormality continues after a lapse of a predetermined time and the rotation speed is equal to or higher than a predetermined value. The fuel supply to the engine was stopped.

<Embodiment> An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 2, a throttle valve 3 is provided in the intake passage 2 of the internal combustion engine 1. An auxiliary air passage 4 that bypasses the throttle valve 3 is provided, and an auxiliary air control valve 5 is interposed in the auxiliary air passage 4.

The control device 6 including a microcomputer includes an ON / OFF detection signal of the idle switch 7 that is turned on at the fully closed position of the throttle valve 3 and is turned off at other positions, and a predetermined crank angle position (for example, 180 ° for four cylinders). ), An output signal of a crank angle sensor 8 serving as a rotation speed detection unit for outputting a reference signal to a reference numeral, and a water temperature sensor 9 for detecting a cooling water temperature.
And the detection signal of are input.

The control device 6 operates according to the flowcharts of FIGS. 3 and 4 and controls the opening degree of the idle control valve 5. Further, the control device 6 drives and controls the fuel injection valve 10 to control the fuel supply amount to the engine.

Here, the control device 6 constitutes an abnormality detecting means, a fully closed command signal output means, a time measuring means, and a fuel supply stopping means.

In addition, 11 is an air flow meter and 12 is an air cleaner.

Next, the operation will be described with reference to the flowcharts of FIGS. 3 and 4.

First, the fuel injection control by the fuel injection valve 10 will be described.
The basic injection amount T _p = K × Q / N (K is a constant) is calculated from the detected intake air flow rate Q and the engine rotation speed N, and
After calculating various correction coefficients COEF mainly according to the water temperature, the air-fuel ratio feedback correction coefficient α, and the correction coefficient T _s based on the battery voltage, the fuel amount T _i = T _p × COEF × α + T _s is calculated.

Then, in synchronization with the ignition signal or the like, the control device 6 outputs a drive pulse signal having a pulse width corresponding to the fuel amount T _i to the fuel injection valve 10 to supply fuel to the engine.

The auxiliary air control by the auxiliary air control valve 5 will be described. When the throttle valve is fully closed during deceleration operation, the opening control of the auxiliary air control valve is started based on the duty signal corresponding to the fully closed state. The intake negative pressure is prevented from rising excessively.

After that, when the feedback control condition of the idle rotation control is satisfied, the auxiliary air amount is feedback-controlled to keep the actual rotation speed at the target idle rotation speed.

Specifically, the control value is set from the basic control value set from the cooling water temperature and various correction values such as air conditioner correction. Then, the duty signal corresponding to this control value is used to control the auxiliary air amount to the auxiliary air control valve. Also,
The detected actual rotational speed is compared with the target idle rotational speed set by the cooling water temperature, and the feedback correction value is set so that the actual rotational speed becomes the target idle rotational speed. I am trying to correct the value.

During such control, the routine shown in the flowchart of FIG. 3 is executed.

In S1, it is determined whether or not the control system (auxiliary air control device) is abnormal based on the self-diagnosis result obtained in the abnormality detection routine described later. If YES, the process proceeds to S2, and if NO, the process proceeds to S10.

In S2, a fully-closed command signal is output to a fully-closed relay (not shown) to fully close the auxiliary air control valve 5 to stop energizing the drive solenoid of the auxiliary air control valve 5, and then the process proceeds to S3. Here, the auxiliary air control valve 5 is configured to be fully closed by the biasing force of the spring when the energization of the drive solenoid is stopped. The fully closed command signal is sent to the control device 6
Will be emitted continuously during the operation of.

In S3, after the timer starts counting, the process proceeds to S4.

In S4, the timer determines whether or not the count time is equal to or greater than a predetermined value. If YES, the process proceeds to S5, and if NO, the routine ends.

In S5, it is determined whether the fuel supply to the engine is stopped, and the YE
If S, proceed to S8, and if NO, proceed to S6.

In S6, it is determined whether or not the detected actual rotation speed N is equal to or higher than the fuel cut setting rotation speed N _{cut, and} if YES, the processing proceeds to S7.
When O, terminate the routine.

In S7, the output of the drive pulse signal to the fuel injection valve 10 is stopped, and the fuel supply to the engine is stopped.

On the other hand, in S8, it is determined whether or not the detected actual rotation speed N is equal to or lower than the recovery setting rotation speed N _REC lower than the fuel cut rotation speed N _cut . If YES, the process proceeds to S9, and if NO, the process proceeds to S7. Continue to stop the return fuel supply.

In S9, the output of the drive pulse signal to the fuel injection valve 10 is restarted, and the fuel supply to the engine is restarted.

In S10, the count value of the timer is reset to the initial value, and then the process proceeds to S9.

With this configuration, after the full-close command signal is output when the control system abnormality is detected, the abnormality continues after a predetermined time has elapsed from the start of the abnormality detection, and the actual rotation speed is the fuel cut rotation speed N _cut. When the stop of the fuel supply to the engine is started at the above time, and further when the abnormality of the control system is continuously detected, the fuel supply is continuously stopped until the actual speed decreases to the recovery speed N _REC. To be done.

Next, the abnormality detection routine will be described based on the flowchart of FIG.

In S11, it is determined whether or not the feedback control condition at the time of idling is satisfied. If YES, the process proceeds to S12, and if NO, the routine ends.

In S12, it is determined whether or not the detected actual engine speed N is larger than the target idle speed N _s by a predetermined value or more, and YES
If NO, the process proceeds to S13, and if NO, the routine ends.

In S13, it is determined whether the feedback correction value is out of the allowable range. If YES, the process proceeds to S14, and if NO, the routine ends.

In S14, it is determined whether or not the states of S12 and S13 have continued for a predetermined time. If YES, the process proceeds to S15, and if NO, the routine ends.

In S15, the abnormality detection of the control system is considered based on the determination results of S12 to S14, and this abnormality detection is stored in the RAM.

As described above, when an abnormality in the control system is detected, a full-close command signal is output, and when the abnormality continues after a predetermined time has elapsed and the actual rotation speed is equal to or higher than the fuel cut rotation speed. Since the fuel supply to the engine is stopped and the fuel supply is restarted when the speed reaches the recovery set speed, the following effects can be obtained.

That is, when the auxiliary air control valve 5 normally operates due to a temporary failure of a part of the control device 6, the auxiliary air control valve 5 operates as a spring at the stage of outputting the fully closing command signal. Since it is normally fully closed by the urging force, it is possible to suppress an increase in the number of revolutions without stopping the fuel supply, and it is possible to prevent the vehicle traveling from being hindered. Further, since the fuel supply is stopped when the abnormality continues due to the output of the fully closed command signal and the rotation speed is equal to or higher than the fuel cut rotation speed, for example, the auxiliary air control valve 5 is locked to the fully open side due to a failure. Even if the amount of supplementary air does not decrease, the engine speed can be suppressed to a value below the risk of runaway, thus ensuring vehicle safety.

<Effect of the Invention> As described above, the present invention, when an abnormality occurs in the auxiliary air control device, outputs the auxiliary air control valve full-close command signal, and then the abnormality continues after a predetermined time elapses. Since the fuel supply to the engine is stopped when the number of revolutions is equal to or higher than the predetermined value, it is possible to prevent the engine from running out of control while preventing the vehicle from running unhindered, thereby ensuring the safety of the vehicle.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention, FIG. 2 is a configuration diagram showing an embodiment of the present invention, and FIGS. 3 and 4 are flowcharts of the same. 3 ... Throttle valve, 4 ... Auxiliary air passage, 5 ... Auxiliary air control valve, 6 ... Control device, 8 ... Crank angle sensor, 10 ... Fuel injection valve

Claims (1)

[Scope of utility model registration request] 1. An internal combustion engine including an auxiliary air control device for controlling an amount of auxiliary air in an auxiliary air passage bypassing a throttle valve by an auxiliary air control valve, and an abnormality detecting means for detecting an abnormality of the auxiliary air control device, A rotation speed detecting means for detecting an engine rotation speed, a full closing command signal outputting means for outputting a full closing command signal to fully close the auxiliary air control valve when the abnormality is detected, and at the time of starting the abnormality detection or Timing means for starting timing from the time when the full-closed command signal is output, and stopping fuel supply to the engine when an abnormality continues to be detected and the engine speed is equal to or higher than a predetermined value after a predetermined time has elapsed from the start of timing. An auxiliary air control device for an internal combustion engine, comprising: