JP2005330972A - Method for driving throttle valve - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for driving a throttle valve for preventing intake air flow noise when an engine is stopped. <P>SOLUTION: This method includes a step of holding the throttle valve at a first opening regulated by a position of a stopper when a motor is not energized, a step of holding the throttle valve at a second opening on the closure side of the first opening, a step of determining if an internal combustion engine is substantially stopped after the switch of the internal combustion engine is put off, and a step of maintaining the throttle valve at the second opening when it is determined that the internal combustion engine is not substantially stopped, and returning the throttle valve from the second opening to the first opening after it is determined that the internal combustion engine is substantially stopped. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for controlling a throttle valve that adjusts the amount of intake air to the internal combustion engine, and more particularly to a method for driving the throttle valve when the internal combustion engine is stopped.

  In recent years, the throttle valve of an internal combustion engine of a vehicle is controlled by being driven by an actuator including a motor, an electromagnetic clutch, and the like according to a driver's accelerator operation amount. FIG. 4 schematically shows such an electronically controlled throttle 10. As shown in FIG. 4, when the motor is not energized, the throttle valve 21 is biased to the open side by a spring 23 and is opened to an opener position defined by a throttle opener stopper 25 (shown by a solid line in FIG. 4). Energization cut position). During the idling speed control, the motor is energized, and the throttle valve 21 is controlled to be held at a predetermined opening on the closing side from the opener position by driving the motor (idling indicated by a broken line in FIG. 4). Position or fully closed position).

  However, such a conventional throttle control may cause the following problems. That is, in the conventional throttle control, when the ignition (IG) switch is turned off during the idling rotation control, the power supply to the engine is stopped and the power supply to the actuator is also cut off. Accordingly, since the throttle valve is not driven by the motor, the throttle valve 21 is opened to the opener opening by the bias of the spring 23. At this time, the engine continues to rotate due to inertia, and the air passage sucked into the engine suddenly widens when the throttle valve 21 returns to the opener opening, so that there is a possibility that the airflow noise of the intake air is generated.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of driving a throttle valve that can prevent intake airflow noise when the engine is stopped.

  According to a first aspect of the present invention, there is provided a method for driving an electronically controlled throttle, comprising: a step of holding the throttle valve at a first opening defined by a stopper position when the motor is not energized; Holding the throttle valve at the second opening on the closing side, and determining whether the internal combustion engine has substantially stopped after the internal combustion engine switch is turned off. When it is determined that the internal combustion engine is not substantially stopped, the throttle valve is maintained at the second opening, and after it is determined that the internal combustion engine is substantially stopped, the throttle valve is The method further includes the step of returning from the second opening to the first opening, whereby the above object is achieved.

  According to a second aspect of the present invention, there is provided a driving method for an electronically controlled throttle according to the first aspect, wherein the internal combustion engine is substantially operated when a predetermined time elapses after the engine speed becomes smaller than a predetermined value. By determining that the operation has stopped, the above object is achieved.

  As described above, according to the throttle valve driving method of the present invention, it is possible to prevent intake airflow noise when the engine is stopped.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In the present embodiment, the case where the electronic control throttle 10 having the configuration shown in FIG. 4 is controlled will be described. As described above, in the electronically controlled throttle 10, when the motor is not energized, the throttle valve 21 is held at the first opening degree (hereinafter referred to as the opener position) defined by the throttle opener stopper 25. During idling, the throttle valve 21 is held at a second opening that is closer to the first opening (hereinafter referred to as an idling position).

  In the throttle valve driving method according to the present invention, the motor is not cut off immediately after the ignition switch (that is, the engine switch) is turned off, and the throttle valve 21 is moved from the idling position to the open position by driving the motor. To drive. At this time, the throttle valve 21 is returned to the opener position at a predetermined speed. This opener position is a motor energization cut position when the engine is stopped.

  Further, when viewed from the engine (internal combustion engine) rotation speed, after the ignition switch is turned off, the rotation due to the inertia of the engine substantially stops, and then the throttle valve 21 is returned from the idling position to the opener position.

  The throttle control as described above can be performed by, for example, a control system schematically shown in FIG. As shown in FIG. 1, a signal (IGS / W) indicating ON / OFF of the ignition switch and a signal (NE) indicating the engine speed are input to the computer (ECU) 11. Furthermore, a throttle opening sensor voltage signal (TAAD) indicating the opening of the throttle valve is input from the throttle opening sensor 31 to the ECU 11. As described below, the ECU 11 outputs a drive signal for driving the actuator (motor) 12 based on these input signals. The throttle valve 21 is driven by the actuator 12 as shown below.

  Hereinafter, the driving method of the throttle valve according to the present invention will be described in more detail with reference to the flowchart of FIG. FIG. 2 is a flowchart showing a control routine of the throttle valve according to the present embodiment. This control routine is a routine for controlling the throttle valve drive when the engine is stopped, and is executed, for example, every 8 ms.

  First, it is determined whether or not it is immediately before the engine is started, depending on whether or not the timing of the ignition switch changes from OFF to ON (step 100). When the ignition switch changes from OFF to ON, it is determined that the engine is immediately before starting, and the output value (TAAD) of the throttle opening sensor 31 at this time is stored as a throttle opening sensor voltage learning value (GTAI) ( Step 110). This voltage learning value (GTAI) indicates the throttle valve opening when the throttle valve 21 is in the throttle opener stopper position before the motor is energized, and is used as a reference value for returning the throttle valve to the opener position.

  If it is determined in step 100 that the engine is not immediately before starting, it is next determined whether or not the engine is operating (step 120). In step 120, it is determined whether or not the ignition switch is turned off. If the ignition switch is kept on, it is determined that the engine is currently operating, and the routine is terminated without executing this control.

  If it is determined in step 120 that the state of the ignition switch has been turned off from on, it is determined whether the engine speed (NE) has become less than 400 rpm after the ignition switch is turned off (step 130). . If the engine speed is 400 rpm or more, the counter (CSLTOPN) is cleared (step 140) and the routine is terminated. This counter is for determining the elapsed time after the engine speed is less than 400 rpm.

  If it is determined in step 130 that the engine speed is less than 400 rpm, it is further determined whether or not the counter value (CSLTOPN) exceeds a predetermined time (T1) (step 150). If the counter value (CSLTOPN) does not exceed the predetermined time (T1), this routine is terminated.

  If the counter value (CSLTOPN) exceeds the predetermined time (T1), it can be determined that the engine has substantially stopped. This is because, after the ignition switch is turned off, the engine continues to rotate due to its inertia, so that it is considered that the engine stops after a predetermined time due to resistance such as friction. The predetermined time T1 may be a time sufficient for the engine speed to reach 0 rpm.

  When the counter value (CSLTOPN) exceeds a predetermined time (T1), the target opening (STEPT) for driving the throttle valve 21 toward the opener opening (stopper position) is set to the current throttle opening (SETPC). As a value obtained by adding a predetermined value (KOFFUP) to (step 160), the throttle valve 21 is driven. The predetermined value KOFFUP is a control range of the throttle valve opening in one routine.

  Then, it is determined by the throttle opening sensor 31 whether the throttle valve 21 is driven until the current throttle opening sensor voltage (TAAD) becomes equal to or higher than the voltage learning value (GTAI) of the throttle opener position learned in step 110. When the voltage learning value (GTAI) has not been reached, the control routine is terminated. After it is determined in step 170 that the voltage learning value (GTAI) has been reached, energization of the motor is interrupted (step 180), and this control is terminated.

  As described above, in the present embodiment, as shown in FIG. 3, the engine speed until the engine is substantially stopped, that is, after the engine speed becomes lower than a predetermined speed (for example, 400 rpm). The throttle valve opening is maintained as it is (idling position) for a sufficient time (T1) to become 0 rmp. After the elapse of time T1, the throttle valve is driven by energization of the motor, and the throttle opening is increased by a predetermined opening in one routine toward the opener position. At this time, the sensor voltage value from the throttle opening sensor is monitored and compared with the throttle opening sensor voltage learning value (GTAI) at the opener position learned before the engine is started. Determining the degree of power cut.

  Accordingly, the intake airflow noise can be eliminated by opening the throttle valve to the open position after the engine rotation is substantially stopped, that is, after the air flow caused by the engine rotation is substantially stopped. Also, since the throttle valve is returned to the opener position at a predetermined speed when the motor is energized, a sudden collision with the opener stopper of the throttle valve is avoided, the impact on the opener stopper is reduced, and the interference sound between the throttle valve and the opener stopper Can be eliminated.

It is a figure which shows typically the control system of the throttle valve by one Embodiment of this invention. It is a flowchart which shows the control routine of the throttle valve by one Embodiment of this invention. It is a time chart which shows control of the throttle valve at the time of an engine stop by one embodiment of the present invention. It is a figure which shows typically the structure of the electronically controlled throttle to which one Embodiment of this invention is applied.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Electronically controlled throttle, 11 ... Computer (ECU), 12 ... Actuator, 21 ... Throttle valve, 23 ... Spring, 25 ... Throttle opener stopper, 31 ... Throttle opening sensor

Claims (2)

Holding the throttle valve at the first opening defined by the stopper position when the motor is de-energized;
Holding the throttle valve at a second opening that is closer to the first opening than at the first opening;
A method for driving an electronically controlled throttle including
Determining whether the internal combustion engine has substantially stopped after the internal combustion engine is switched off;
When it is determined that the internal combustion engine is not substantially stopped, the throttle valve is maintained at the second opening, and after it is determined that the internal combustion engine is substantially stopped, the throttle valve is A step of returning from the second opening to the first opening;
Driving method. The driving method according to claim 1, wherein it is determined that the internal combustion engine has substantially stopped when a predetermined time elapses after the engine speed becomes smaller than a predetermined value.

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