JPH04203219A - Throttle valve control device for engine - Google Patents

Abstract

PURPOSE:To hold a throttle valve in its opening position irrespective of time passage by opening the throttle valve to a specified opening position by means of an energizing force of an energizing means, and releasing a passage in an intake tube by a specified rate, when a driving force of a driving device is interrupted. CONSTITUTION:When an engine is stopped, an adjusting bolt 10 of a lever 8 is abutted onto a plunger 12 of a second energizing means 9 by means of energizing force of a back spring 15. An energizing force F2 of a spring 13 of the second energizing means 9 is larger than an energizing force F1 of the back spring 15, so that a throttle valve 2 is held to a position theta1 of a specified opening (an initial opening). Under such a condition, icing of the throttle valve 2 is previously prevented. When the engine is started from such a condition, the opening of the throttle valve 2 is controlled by means of a driving motor according to an operation condition of the engine. The lever 8 is rotated against the energizing force F2 of the spring 13 while pressing a plate 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an engine throttle valve control device that electrically controls the opening degree of an engine throttle valve.

[Prior Art] Generally, in this type of device, the throttle valve is always biased in the fully closed direction by the biasing force of a back spring. The biasing force of the back spring is normally set to be larger than the torque of the control motor when it is not energized, so even if the control circuit fails while controlling the opening of the throttle valve, the energization to the motor is stopped. This allows the throttle valve to be operated in the fully closed direction.

As a prior art of this kind, Japanese Patent Application Laid-Open No. 56-1483
4, Japanese Unexamined Patent Publication No. 51-138235, etc. have been proposed.

However, with the throttle valve control device, the throttle valve is always kept fully closed when the engine is stopped, so the throttle valve or throttle shaft may freeze (so-called icing) in cold regions or extremely low temperatures. Fixation)
In this case, it becomes impossible to open the throttle valve, which may cause a problem that the engine cannot be operated satisfactorily. Furthermore, if sticky substances such as combustion products resulting from combustion in the engine land on the throttle valve, a problem similar to the above-mentioned freezing may occur.

In order to deal with such problems, it has been proposed in the past, for example, in Japanese Patent Laid-Open No. 1983-1.5044.9, to open the throat valve by a predetermined amount when the engine is stopped. In the engine throttle valve control device of this publication, in addition to the first urging means for urging the throttle valve in the closing direction, a second urging means for urging the throttle valve in the opening direction is provided, When the engine is stopped, the throttle valve is opened to a predetermined opening degree through a balanced relationship between the two biasing means.

[Problems to be Solved by the Invention] However, in the prior art described above, the opening degree (opening amount) of the throttle valve is determined by the balanced position of both the first and second urging means. Not only is the opening position not accurate, but there is a risk that the throttle valve opening position may change due to changes in the biasing means over time.

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art described above, and its purpose is to accurately open the throttle valve to a predetermined opening position when the engine is stopped, and to do so. An object of the present invention is to provide a throttle valve control device for an engine that can maintain an opening position without changing over time.

[Means for Solving the Problems] A throttle valve control device for an engine according to the present invention that solves the above problems includes: a throttle valve provided in an intake pipe of the engine to adjust the flow rate of combustion air; and an opening control device for the throttle valve. a control means for determining the throttle angle in accordance with at least an accelerator amount; a drive means for driving the throttle valve between a fully closed position and a fully open position according to an electric signal from the control means; and a drive means for driving the throttle valve in a closing direction. a first biasing means for biasing the throttle valve to a predetermined opening degree or less;
and second urging means for urging in the opening direction with a larger urging force than the urging force of the urging means.

[Function] According to the above means, during engine operation, the throttle valve is opened and closed by the driving force of the driving means against the urging force of the first urging means when the opening degree exceeds the predetermined opening degree, and when the opening degree exceeds the predetermined opening degree. Below, it is opened and closed against the urging force of the second urging means.

When the driving force from the driving means is cut off, the throttle valve is opened to a predetermined opening position by the urging force of the second urging means, and the passage in the intake pipe is opened by a predetermined amount.

[Example] An embodiment of the present invention will be described below with reference to the drawings.

The first diagram shows a side view of the engine throttle valve control device.
In FIG. 2, which shows the figure and its plan sectional view, a throttle valve 2 is provided in an intake pipe 1 of an engine so as to be rotatable by a throttle shaft 3. As shown in FIG. Throttle valve 2
adjusts the flow rate of combustion air flowing through the intake passage 1a in the intake pipe 1 by its rotation.

One end (the upper end in FIG. 2) of the throttle shaft 3 passes through the wall of the intake pipe 1, and a driven gear 20 is fixed to the end. A drive motor 4 consisting of a step motor is externally attached to the intake pipe 1. A drive gear 21 fixed to the output shaft of the drive motor 4 is meshed with the driven gear 2o. Therefore, the drive motor 4
By controlling the rotation of the throttle valve 2, the opening degree of the throttle valve 2 can be adjusted.

The drive motor 4 is connected to a control device 7 that determines the amount of rotation of the throttle valve 2 in accordance with a signal from an accelerator sensor 6 or the like that detects the amount of depression of the accelerator pedal operated by the driver, as in the conventional device described above. is driven by an electrical signal.

The other end of the throttle shaft 3 (the lower end at -6 to -6 in FIG. 2) also passes through the wall of the intake pipe 1, and a lever 8 is inserted and fixed into this end. The lever 8 is attached perpendicularly to the throttle shaft 3, and its front and rear ends extend along the front and rear direction of the intake pipe l.

A stopper 16 is provided on the side wall of the intake pipe 1 and faces the left end of the lever 8 in the drawing. The stopper 16 includes an adjustment bolt 1 screwed into a mounting piece 19 attached to the side wall.
8 and an adjustment nut 17 screwed into the bolt 18.

Further, both ends of a coiled back spring 15 are hung on a left side extension of the lever 8 and a stay 15a externally attached to the intake pipe 1, respectively.

The biasing force of the back spring 15 causes the end of the lever 8 to move toward the stopper 1 in the closing direction of the throttle valve 2.
The throttle valve 2 is biased in the direction in which it comes into contact with the tip of the adjustment bolt 18 of No. 6 (clockwise direction in FIG. 1). Further, when the lever 8 comes into contact with the adjustment bolt 18 of the stopper 16, the throttle valve 2 is in a fully closed state (idle link state). This state is shown in a side view in FIG. 3, and in FIG. 1, the throttle valve 2 is shown by a chain double-dashed line. Also, the adjustment bolt/nut 1 of the stopper 16
The fully closed position of the throttle valve 2 can be adjusted depending on the degree of screw engagement of 8.17.

In FIG. 1, the right end of the lever 8 is provided with a bent piece 8a.
Or is provided. An adjustment bolt IO is screwed into the bent piece 8a, and an adjustment nut 9 is screwed into the bolt 10.

A second biasing means 9 is provided on the side wall of the intake pipe 1 and faces an adjustment bolt 10 provided at the end of the lever 8 . This second biasing means 9 includes a case 14 screwed to a bracket 9a provided on the side wall of the intake pipe 1, and a plate 12 that is housed in the case 14 so as to be movable up and down and that can come into contact with the adjustment bolt 10. and a spring 13 which is housed in the case 14 and urges the plate 12 upward in FIG. Note that the plate 12 is the case 1
The removal is prevented by the stopper portion 14a of No. 4.

Due to the biasing force of the spring 13, the throttle valve 2
is biased in the opening direction (counterclockwise direction in FIG. 1).

Furthermore, when the adjustment bolt 10 comes into contact with the plate 12, the throttle valve 2 is not in a fully closed position, but is at a predetermined opening degree θ1 that slightly opens the intake passage 1a. This predetermined opening degree θ1 is determined by the adjustment bolt/nut 10.11 and the second biasing means 9.
It can be adjusted by the degree of screwing of the case 14.

Therefore, the biasing force F1 of the pack spring 15 and the biasing force F2 of the spring 13 of the second biasing means 9 are F1. It is set to satisfy the relationship <F 2 . Further, the torque generated by the drive motor 4 is set to be larger than the biasing force F1 of the back spring 15 and the biasing force F2 of the spring 13. Therefore, when the drive motor 4 is driven, the throttle valve 2 is rotated to open and close against the urging force of the back spring 15 and the second urging means 9.

In the engine throttle valve control device, when the accelerator pedal 5 is depressed and a signal corresponding to the amount of depression is input from the accelerator pedal 6 to the control device 7, the control device 7 outputs a drive signal to the drive motor 4. , drives the drive motor 4.

The rotation of the output shaft of the drive motor 4 is transmitted to the throttle shaft 3 via the drive gear 21 and the driven gear 20.
The opening degree of the throttle valve 2 is adjusted according to the amount of depression of the accelerator 5.

Specifically, when the engine is stopped, as shown in FIG. is in a state of At this time, since the biasing force (set load) F2 of the spring 13 of the second biasing means 9 is larger than the biasing force Fl by the back spring 15, the throttle valve 2 is opened to a predetermined opening (hereinafter, this opening is (referred to as the initial opening degree) is held at the position θl.

In this way, the throttle valve 2 is set to the initial opening position, and the engine is ready for starting. By maintaining this state, the throttle valve 2 can be prevented from sticking due to sticky substances such as combustion products generated between the intake pipe 1 and the throttle valve 2.
Alternatively, it is possible to prevent the throttle valve 2 from freezing and sticking at extremely low temperatures.

Further, when the engine is started from this state, the opening degree of the throttle valve 2 is controlled by the drive motor 4 according to the operating state of the engine. Here, to explain the state in which the engine has been warmed up and the accelerator pedal 5 is released, the opening degree of the throttle valve 2 is controlled by the drive motor 4 to be below the initial opening degree θ1 as shown in FIG. Ru.

At this time, the lever 8 is activated by the spring I3 of the second biasing means 9.
The plate 12 is pushed and rotated against the urging force F2, and the amount of rotation is stopped by the lever 8 coming into contact with the adjustment bolt 18 of the stopper 16.

Furthermore, when the accelerator pedal 5 is depressed in the above state, the throttle valve 2 is opened through the initial opening degree θ1. At this time, the throttle valve 2 is opened and closed against the biasing force Fl of the back spring 15 at an initial opening degree of 01 or more.

Further, when the ignition key switch is turned off and the engine is stopped, power to the drive motor 4 is also cut off. Then, as shown in FIG. 1, the throttle valve 2 is opened to the initial opening degree θ1 position by the urging force of the second urging means 9, and the passage 1a in the intake pipe 1 is opened by a predetermined amount.

According to the engine throttle valve control device, when the driving force of the drive motor 4 is cut off, the throttle valve 2 is switched to the second
Since the throttle valve is held at the initial opening θ1 position by the urging force of the urging means 9, compared to the conventional system in which the throttle valve is held at a predetermined opening by a balanced relationship between the first and second urging means,
The throttle valve 2 can be opened to a predetermined opening degree θ1 with high precision, and the predetermined opening position can be maintained without changing over time.

Incidentally, in the above embodiment, the control device 7 constitutes the control means of the present invention, the drive motor 4 constitutes the drive means of the present invention, and the pack spring 15 constitutes the first urging means of the present invention. It consists of

Note that the present invention is not limited to the above-mentioned embodiments, and modifications can be made without departing from the gist of the present invention. For example, the second biasing means 9 may include a coil spring 13
In addition, the same effects as in the embodiment can be obtained using an elastic body such as a leaf spring or elastic rubber.

[Effects of the Invention] According to the present invention, the first
In addition to the urging means, a second urging means is provided which urges the throttle valve in the opening direction with a urging force greater than the urging force of the first urging means when the throttle valve is opened at a predetermined opening degree or less. As a result, when the driving force of the driving means is cut off, the throttle valve is held at a predetermined opening position by the urging member J of the second urging means. Compared to a system in which the throttle valve is opened to a predetermined opening degree using a balanced relationship between means, the throttle valve can be opened to a predetermined opening degree with high precision, and the predetermined opening position can be maintained without any change over time. .

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is a side view of an engine throttle valve control device, FIG. 2 is a plan sectional view thereof, and FIG. 3 is a side view when the throttle valve is fully closed. . 1... Intake pipe 2... Throttle valve 4... Drive motor (drive means) 7... Control device (control means) 9... Second urging means

Claims (1)

[Scope of Claims] A throttle valve provided in an intake pipe of an engine to adjust the flow rate of combustion air; a control means for determining the opening degree of the throttle valve in accordance with at least an accelerator amount; a driving means for driving the throttle valve between a fully closed position and a fully open position in response to an electrical signal; a first urging means for urging the throttle valve in the closing direction; and a first urging means for urging the throttle valve in the closing direction; When the temperature is below the first
2. A throttle valve control device for an engine, comprising: a second biasing means for biasing in the opening direction with a biasing force greater than the biasing force of the biasing means.