JPS59119036A - Throttle valve control device for engine - Google Patents

Abstract

PURPOSE:To enhance the reliability by judging a presence of a failure of a throttle valve control device and indicating it based on a difference between a throttle valve opening command signal and a real opening at the time of an initial start-up of an engine where the throttle valve is controlled by an accelerator opening signal. CONSTITUTION:In a device which has an accelerator pedal stroke amount detector and controls the throttle valve opening by driving a step motor in response to the stroke amount, a command (S02) is outputted to open the throttle valve to a desired position at an initial stage of the ignition switch operation. The difference between the command opening and real throttle valve opening is detected, and if the difference is within an allowable value, a 'normal' judgment is made and the following step is proceeded to. If it exceeds the allowable value, a 'failure' judgment is made (S04) and it is so indicated (S13). Likewise, above-described judgments are repeated with the throttle valve opened and closed by a small amount in order to decide a presence of a failure of the throttle valve control device in a short time (0.5sec) in the initial start-up period.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine throttle valve control device that extracts the opening degree of an accelerator pedal as an electrical signal and electrically controls the throttle valve opening degree based on this opening signal.

In general, an engine throttle valve control device controls the opening and closing of the throttle valve according to the movement of the accelerator pedal when the driver depresses the accelerator pedal. It is necessary to accurately match the movement with the opening and closing of the throttle valve. By the way, if the accelerator pedal and the throttle valve are connected by a link mechanism or a wire mechanism, the movement of the accelerator pedal is transmitted to the throttle valve through reciprocating motion or rotational motion, resulting in a very complicated structure. Moreover, because the links and other connecting parts tend to rattle, there is a problem that the follow-up performance of the throttle valve is not very good.Furthermore, due to large friction, a large amount of force is required to operate the accelerator pedal. There is a problem with this.

In addition, in the mechanical connection structure between the accelerator pedal and the throttle valve as described above, since the opening degrees of the accelerator pedal and the throttle valve correspond one-to-one, the opening degree of the throttle valve can be adjusted according to external conditions such as engine cooling water temperature. There are problems that are minute and cannot be properly controlled.

Therefore, as a throttle valve control device that has solved this problem, we have developed a so-called electric control system that extracts the movement of the accelerator pedal as an electric signal and uses this electric signal to operate an actuator to open and close the throttle valve. There is (JP-A-51-138235
(see publication).

By the way, the method of electrically linking and controlling the accelerator pedal and throttle valve has the advantage that the basic accelerator pedal opening signal can be modified according to operating conditions such as cooling water temperature, and the optimal throttle valve opening can be set. However, in practical terms, the problem with longevity is its reliability.

In other words, whether the control circuit of the device is operating correctly, whether the actuator is operating correctly even if the control circuit is operating correctly, and whether the actuator is operating correctly even if the actuator is operating correctly. There is a problem inherent to electric control systems, such as the throttle valve not opening or closing properly due to prying.

The present invention was made in view of such reliability problems, and it is important to check whether the throttle valve is opened and closed correctly, in other words, whether or not the control system, actuator, and throttle valve are operating correctly. It is an object of the present invention to provide an engine throttle valve control device which checks in advance whether or not the engine is activated at the initial stage of starting the engine, thereby ensuring reliability.

For this reason, the present invention outputs a command signal to open the throttle valve to a predetermined opening by utilizing the very initial short time lag between operating the ignition switch and starting the engine, and uses this command signal to open the throttle valve. Failure determination that detects the difference between the actual opening of the throttle valve that is activated and opened and the throttle valve opening that is commanded by a command signal, and determines whether or not there is a failure in the throttle valve control device based on the state of this difference. The basic feature is that the device is incorporated into a throttle valve control device.

Hereinafter, the present invention will be described in more detail based on illustrated embodiments.

In FIG. 1 showing the overall system of the throttle valve control device,
Reference numeral 1 denotes an accelerator pedal, 2 an accelerator opening degree detector that detects the opening degree of the accelerator pedal 1 in response to depression of the accelerator pedal 1, and 3 a throttle valve control circuit 54 configured using a microcomputer that receives the output of the control circuit 3. This is a driver circuit that drives and controls a step motor 5 as an actuator.The output shaft of the step motor 5 is connected to the rotating shaft of a throttle valve 7 disposed in an intake passage 6, and the step motor 5 opens and closes the throttle valve 7. Operate.

The control circuit 3 uses the accelerator opening detected by the accelerator opening detector 2 as a basic human power signal, and further includes:
A throttle valve opening signal from a throttle valve opening detector 8 that detects the opening of the throttle valve 7, and a rotation signal from an engine rotation detector 9.

A water temperature signal from the engine cooling water temperature detector 10.

The input signals are an on/off signal of the ignition switch IgSw and an on/off signal of the starter switch 5LSW.

The control circuit 3 executes a control program for the throttle valve 7 according to the flowchart shown in FIG. 2 based on the above input signals.

In the following description of FIG. 2, 501 to S25 represent each program step.

First, in the steps from SOl to 513, the very short time lag from when the ignition switch IgSw is turned on (SQL) to when the starter switch StSw is turned on (514) is used to determine whether there is a failure in the throttle valve control device. Determine.

Now, when the ignition switch I gSw is turned on at SOl, the control circuit 3 outputs a throttle valve fully closed command signal to the driver circuit 4 at 502, and the driver circuit 4 drives the step motor 5 in the fully closed direction, and the throttle valve is closed. Fully close valve 7. Next, in S'03, the throttle valve opening is read from the throttle valve opening detector 8 in order to detect whether or not the throttle valve 7 is actually fully closed by the throttle valve fully closed command. It is determined whether the valve opening degree (detected value) is fully closed or not, and if it is not fully closed, the process immediately jumps to step 513 to display a malfunction and warn the driver of the malfunction.

When the throttle valve 7 is actually fully closed, S0
5 outputs a throttle valve opening change command to open the throttle valve by a predetermined angle △θ, and the driver circuit 4 drives the step motor 5 in the opening direction to fully open the throttle valve 7 by a predetermined angle △θ.
Open by θ. Note that the predetermined angle Δθ is set as an angle obtained by dividing the angle from fully closed to fully open by an appropriate integer, for example, 3.

Then, in 506, the throttle valve opening at that time is read from the throttle valve opening detector 8 in order to determine whether or not the throttle valve 7 is actually opened by Δθ according to the throttle valve opening change command, and in SO7 , the difference between the detected value and the command value (Δθ) is determined, and it is determined whether this difference is within a preset tolerance range. When the difference between the command value and the detected value exceeds the allowable error, the control circuit 3.
Driver circuit 4. Step motor 5. Since it is thought that some kind of failure has occurred in one of the throttle valves 7, the process jumps to 513 and displays a failure indication.

On the other hand, if the throttle valve 7 is opened correctly within the allowable error range, it is confirmed in S08 that the throttle valve 7 is not fully closed, and the process returns to step S05. In step , the throttle valve opening is further increased by △θ, and it is determined whether the difference between the actual throttle valve opening (detected value) and the command value (2△θ) is within the allowable error range. do. If Δθ is set to 30 degrees, for example, this determination will be repeated three times until the throttle valve opening reaches full open, and if a failure is detected during this process, a failure indication will be made in S13. , when the throttle valve reaches full open without any failure, a failure determination (check) in the direction of closing the throttle valve 7 is performed in steps 509 to 512.

That is, when it is confirmed that the throttle valve 7 is fully open at SO8,
At SO9, a change command (-△θ) to close by a predetermined angle △θ is output, and the throttle valve 7 is changed from fully open to △θ.
Close only. Then, in 510, the actual throttle valve opening is detected, and in S11, it is determined whether the throttle valve opening is correctly closed by △θ, that is, the difference between the command value (90° - △θ) and the detected value is within the allowable error. Determine whether it is within the range.

As mentioned above, when the predetermined angle Δθ is set to 30°, the steps from 509 to Sll are 90-
This is repeated a total of three times: Δθ・90°−2Δθ, fully closed, and a failure check regarding the operation control of the throttle valve 7 in the closing direction is performed.

In the above control steps, a failure check is performed in the opening and closing directions of the throttle valve 7, and if no failure is found, the opening/closing of the throttle valve 7 itself and the operation of the operation control system (3 to 5) are Since it is considered normal, 51
4 to start control in 519.

Note that the time required for the above failure determination is based on the time required for the step motor 5.
Even considering the responsiveness of the engine, the total time can be as short as 0.5 seconds, so failure can be determined within the time lag between turning on the ignition switch and turning on the starter switch StSw. can be done. Furthermore, there are cases where the ignition switch IgSw is turned on and then the starter switch StSw is turned on immediately, but since the failure determination can be completed in a very short time, it is virtually impossible for the driver to feel uncomfortable.

During starting control, the starter switch StS is switched on at 514.
It is checked whether w is turned on, and if it is not turned on yet, the loop to step 514 is repeated until it is turned on.

When the starter switch Stew is turned on, 51
Step 5 detects the starting conditions. In the embodiment shown in FIG. 1, the engine cooling water temperature, which has the greatest influence on engine startability, is read from the water temperature detector 10 as a starting condition.
In step 516, a predetermined opening value of the throttle valve at the time of starting is calculated so that the opening degree is larger when the temperature is low compared to when the temperature is high.

Based on the calculation result of this throttle valve predetermined opening value, S1
7, a predetermined opening command is output to the driver circuit 4 to open the fully closed throttle valve 7 to a predetermined opening value, and the driver circuit 4 drives the step motor 5 to open the throttle valve 7 to a predetermined opening value.
jF7 is opened to the commanded predetermined opening value of the throttle valve, and engine starting is started.

Next, in 518, the output of the rotation detector 9 is read to detect the engine rotation speed, and in 519, it is determined whether the detected engine rotation speed has reached a preset complete explosion rotation speed,
When the number of rotations has not reached the perfect number of revolutions, the number of revolutions is detected repeatedly at regular intervals, and when the number of revolutions gradually increases until the number of revolutions reaches the number of perfect explosions, engine starting is completed and the engine resumes normal operation. Along with this, control of the throttle valve 7 also shifts to normal control based on the amount of depression of the accelerator pedal 1.

That is, normal control of the throttle valve 7 is started by first reading the accelerator pedal depression amount, that is, the accelerator opening from the accelerator opening detector 2 in S20. The read accelerator opening degree is converted into a throttle valve opening value A corresponding to this accelerator opening degree in step 521, and in the next step 522, the current throttle valve opening degree B is read from the throttle valve opening degree detector 8.

The force throttle valve opening value A obtained as above and the current throttle valve opening B are 523, which is the difference between them (A-'
B), and when the difference is zero, that is, when the current throttle valve opening degree B is equal to the throttle valve opening value A, there is no need to change the opening degree of the throttle valve 7, so proceed directly to step S20. Loop.

Furthermore, when the above difference (A-B) is positive, it means that the throttle valve opening value A is larger than the current throttle valve opening B, so in S24, the throttle valve 7 is adjusted by an angle equal to the difference. A throttle valve opening command is output to open the throttle valve, the throttle valve opening is made to correspond to the accelerator opening, and the opening operation is performed, and then the process loops to S20 for the next loop control.

On the other hand, when the above difference (A-B) is negative, conversely, S2
In step 5, a throttle valve closing command is output so as to reduce the throttle valve opening by the above-mentioned difference, and after reducing the throttle valve opening by that amount, the process moves to the next loop control.

Thereafter, the opening degree of the throttle valve 7 is controlled by repeating steps 520 to 825, and the throttle valve opening degree is caused to respond to and follow the accelerator opening degree from time to time.

As is clear from the above description, according to the present invention, it is possible to perform self-diagnosis of the throttle valve control device each time the vehicle is driven, prior to the start of operation, and to detect any malfunction of the throttle valve control device. If there is a failure, it can be detected reliably, and if there is no failure, safety can be confirmed, and there is an advantage that the reliability of the electric control system of the throttle valve can be sufficiently ensured.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the overall system of a throttle valve control device according to the present invention, and FIG. 2 is a flowchart showing the control flow of the control circuit shown in FIG. 1... Accelerator pedal, 2... Accelerator opening detector, 3... Control circuit, Step motor, 7... Throttle valve, 8... Throttle valve opening detector, IgSw. ...Ignition switch.

Claims (1)

[Claims] (1) An accelerator opening detector that outputs an accelerator opening signal according to the amount of depression of the accelerator pedal, an actuator that opens and closes the throttle valve of the engine, and the detection signals of the accelerator opening detector are input, and the accelerator opening is detected. In an engine throttle valve control device including a control sum circuit that outputs an electric signal to drive and control the actuator based on a signal, a command signal is output to the actuator to open the throttle valve to a predetermined opening degree at the initial stage of operation of the ignition switch. In addition, a failure determination device is provided, which detects a difference between the commanded throttle valve opening of the command signal and the actual throttle valve opening, and determines a failure of the throttle valve control device based on the state of the difference. An engine throttle valve control device characterized by: