JP2524047Y2 - Safety mechanism of electric throttle valve - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Purpose of the Invention] (Industrial application field) The present invention relates to an electric throttle which can satisfy a limp home function when an electric actuator fails in an engine having a throttle valve operated by an electric actuator. The present invention relates to a valve safety mechanism.

(Prior Art) In addition to a main throttle valve linked to an accelerator pedal, a secondary throttle valve operated by an electric actuator is provided. When slippage of a drive wheel is detected, the opening of the secondary throttle valve is controlled. A traction control device configured to reduce the engine output and reduce the slip of the drive wheels has been considered.

(Problem to be Solved by the Invention) In such a traction control device, a return spring is attached in a direction to close the sub-throttle valve, for example, assuming that an abnormality occurs in the electric actuator that operates the sub-throttle valve. In this case, there is a problem in that the so-called limp home function is impaired because the engine output is not at all, so that the vehicle can travel to the maintenance shop.

On the other hand, if a return spring is installed in the direction to open the sub-throttle valve, assuming that an abnormality has occurred in the electric actuator that operates the sub-throttle valve, the engine output will suddenly increase and runaway will occur. There is a problem that.

The present invention has been made in view of the above points, and an object of the present invention is to provide an electric throttle valve safety mechanism that can satisfy a limp home function when an electric actuator fails in an engine having a throttle valve operated by an electric actuator. To provide.

[Structure of the Invention] (Means and Actions for Solving the Problems) In an engine configured to control the opening of a throttle valve operated by an electric actuator to control the engine output, the throttle valve is closed. A negative pressure actuator in which a biasing member for biasing the throttle valve is provided; and, when the throttle valve is normal, air is introduced into a negative pressure chamber of the negative pressure actuator to cause the biasing member to close the throttle valve in a valve closing direction. A first switching valve that permits biasing and shuts off the introduction of air when an abnormality occurs, and a first switching valve that rotates the throttle valve in the opening direction against the biasing force of the biasing member when the throttle valve is abnormal. A second switching valve for intermittently introducing a negative pressure downstream of the throttle valve into a negative pressure chamber of the negative pressure actuator. It is.

(Embodiment) Hereinafter, a safety mechanism for an electric throttle valve according to an embodiment of the present invention will be described with reference to the drawings. Intake air sent from an air cleaner (not shown) is mixed with fuel injected from an injection valve (not shown) provided in the path via an electric throttle valve 11 and a surge tank 12 and then is supplied from an intake valve 14 of an engine 13. Inhaled. The opening of the throttle valve 11 is controlled by a stepper motor 15, and the stepper motor 15 is controlled by, for example, a traction control controller (not shown) for reducing slip of the drive wheels. Further, the operating element 17 is pushed in the direction of arrow B by the urging force of the return spring 16S provided in the negative pressure chamber A of the negative pressure actuator 16, and the throttle valve 11 is urged in the fully closed direction. Further, an operating piece 16a of a negative pressure actuator 16 is connected to the throttle valve 11. As described later, the chamber A is normally kept at the atmospheric pressure, and a negative pressure is introduced at an abnormal time. And A
When the pressure in the chamber is reduced, the actuator 17 is moved in the direction opposite to the direction of arrow B, and the throttle valve 11 is configured to rotate in the opening direction. The above chamber A is a normally closed solenoid on-off valve
Negative pressure of the surge tank 12 can be introduced through 18. Further, the chamber A is opened to the atmosphere via a normally-open solenoid valve 19. The open / close control of the electromagnetic on / off valves 18 and 19 is performed by a traction control controller (not shown), and the control unit detects disconnection of the stepper motor 15 and the like.

Next, the operation of the embodiment of the present invention configured as described above will be described. When the stepper motor 15 is in a normal state, the chamber A is open to the atmosphere via the electromagnetic on-off valve 19, and the electromagnetic on-off valve 18 is closed. Therefore, the chamber A of the negative pressure actuator 16 is kept at the atmospheric pressure. For this reason, the opening of the throttle valve 11 is controlled by controlling the stepper motor 15.

On the other hand, when the abnormality of the stepper motor 15 is detected, the traction control control unit cannot control the opening of the throttle valve 11. Thus, the biasing force of the return spring 16S rotates the throttle valve 11 in the fully closed direction. At the same time, the electromagnetic on-off valve 18 is controlled to open and close by duty control, and the electromagnetic on-off valve 19 is controlled to close. Therefore, the negative pressure in the surge tank 12 downstream of the throttle valve 11 is intermittently supplied to the chamber A. When the chamber A is intermittently supplied with negative pressure, the actuator 17 is gradually moved in the direction opposite to the arrow B, and the throttle valve 11 is rotated in the opening direction. By appropriately selecting the duty ratio for opening and closing the electromagnetic on-off valve 18, the throttle valve 11 is rotated to a predetermined opening and stopped at a position where the biasing force of the return spring 16S can be balanced. Therefore, the throttle valve 11 is controlled so as to be opened from the fully closed state by a predetermined opening. Therefore, even if an abnormality occurs in the stepper motor 15, the required minimum intake air amount is secured, and the limp home function is satisfied.

In the above embodiment, the electric throttle valve 11 may electrically detect the depression amount of the accelerator pedal and control the opening degree in accordance with the detection signal. Also,
In addition to the main throttle valve whose opening is mechanically controlled in accordance with the amount of depression of the accelerator pedal, it may be used, for example, as a sub-throttle valve for traction control.

[Effects of the Invention] As described in detail above, according to the present invention, when the electric throttle valve cannot be controlled, a sudden change in speed is prevented so as to gradually control the opening of the throttle valve. As a result, it is possible to provide a safety mechanism of the electric throttle valve that can improve running stability and satisfy the limp home function.

[Brief description of the drawings]

FIG. 1 is a view showing a safety mechanism of an electric throttle valve according to an embodiment of the present invention. 11… Electric throttle valve, 15… Stepper motor, 16…
… Negative pressure actuator, 16S …… Return spring, 18,19 …… Electromagnetic on-off valve.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References Japanese Utility Model Showa 61-140140 (JP, U) Japanese Utility Model Showa 60-173641 (JP, U) Japanese Utility Model Showa 60-81241 (JP, U)

Claims (1)

(57) [Scope of request for utility model registration] An engine configured to control an opening of a throttle valve operated by an electric actuator to control an engine output is provided with an urging member for urging the throttle valve in a closing direction. When the throttle valve is normal, air is introduced into the negative pressure chamber of the negative pressure actuator when the throttle valve is normal, and biasing of the throttle valve in the valve closing direction by the urging member is allowed. A first switching valve for shutting off the throttle valve, and a throttle valve provided in the negative pressure chamber of the negative pressure actuator to rotate the throttle valve in an opening direction against the urging force of the urging member when the throttle valve is abnormal. And a second switching valve for intermittently introducing a negative pressure downstream of the valve.