JPH1037805A - Warming up device for starting of carburetor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve startability of an engine by widely opening a throttle valve also at the time of a very low temperature by providing an actuator so that the advancing and retreating shaft may be opposed to a throttle lever and revolving the throttle lever in the opening direction by projecting the shaft at the time of the very low temperature. SOLUTION: When a temperature sensor 23 senses a cooling water temperature when an on-operation is performed for an ignition switch 23 and the temperature is judged to be -23 deg.C or below in an electronic control part 21, when the cooling water temperature is a very low temperature, a magnetization signal is transmitted to an actuator 20 to be a solenoid valve. The actuator 20 is magnetized and the shaft 20a projects against pressing force of a return spring 20b. As a result, startability of an engine is improved by pressing a pin 4a by the tip 20b, revolving a throttle lever 4 in the opening direction, regardless of a fast idle cam 6 and a starting cam, and widely opening a throttle valve 3 up to an opening which is necessary at the very low temperature of -23 deg.C or below.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a carburetor warm-up device.

[0002]

2. Description of the Related Art Conventionally, in a carburetor for an internal combustion engine, for example, a device as shown in FIGS. 5 to 8 is actually opened as a starting and warming device for improving the startability at a cold start and a warm start. It is disclosed in JP-A-60-116047.

[0003] This conventional device will be described. 1 is a carburetor body, 2 is an intake pipe, 3 is a throttle valve, 3a
Is a throttle shaft, and 4 is a throttle lever.
Reference numeral 6 denotes a fast idle cam having a cam surface 6a formed at one end, which is rotatably provided around the support shaft 5, and is constantly urged clockwise in FIG. Reference numeral 9 denotes an adjusting screw provided on the fast idle cam 6, the tip of which is in contact with the shaft 12 of the thermowax 11. Reference numeral 10 denotes a passage for engine cooling water.

Reference numeral 7 denotes a starting cam having a cam surface 7a formed at one end thereof. The starting cam 7 is rotatably provided around the support shaft 5 and is always inverted by a spring 13 provided between the shaft and the fast idle cam 6 as shown in FIG. Energized clockwise.
The radius of the cam surface 7a of the starting cam 7 and the cam surface 6a of the fast idle cam 6 from the support shaft 5 is larger in the former than in the latter as shown in FIG.

The other end 7b of the starting cam 7 has an electromagnetic valve 1
6 is in contact with the shaft 17. The solenoid valve 16
When the ignition switch 19 is turned on, the shaft 17 is retracted, and when the ignition switch 19 is turned off, the spring 1 is turned on.
8 to protrude.

A stopper 14 is formed on the fast idle cam 6, and a stopper 14 is provided on the stopper 14.
b comes into contact. In the drawing, reference numeral 15 denotes a spring for urging the throttle lever 4 in the closing direction. The spring force of the spring 15 is set to be stronger than the spring force of the spring 13.

In the above configuration, when the normal engine is cold, the fast idle cam 6, the starting cam 7, and the throttle lever 4 have the positional relationship shown in FIG. In this state, if the accelerator pedal is depressed before starting, the throttle lever 4 moves rightward from the position shown in FIG. 6, and the starting cam 7 rotates clockwise in FIG. 6 by the urging force of the spring 18 of the solenoid valve 16. Then, the cam surface 7a is engaged with the throttle lever 4 to be in the state shown in FIG.

In this state, when the ignition switch 19 is turned on to start the engine, the solenoid valve 16 is actuated and its shaft 17 is retracted.
Since the spring force of the spring 5 is set to be larger than the spring force of the spring 13, the throttle lever 4 is maintained in a state of contact with the cam surface 7a of the starting cam 7. Therefore, the engine is started in a state where the opening of the throttle valve 3 is large, the engine is started at a high speed, and the engine is warmed up in a short time.

Next, when the accelerator pedal is depressed for running after warming up, the throttle lever 4 rotates clockwise from the state shown in FIG. As shown in FIG. 7, it moves upward and is released from the throttle lever 4. Therefore, when decelerating in this state, the throttle lever 4 is engaged with the fast idle cam 6 as shown in FIG.
The opening of the throttle valve becomes sufficiently small, and the vehicle speed is reduced to a predetermined low speed.

Further, when the engine is restarted in a warm-up state, the shaft 17 of the solenoid valve 16 is protruded in a state before the start because the ignition switch 19 is in an off state. 5, the fast idle cam 6 is rotated counterclockwise from the state of FIG.
It is below the state of. Therefore, the starting cam 7 is held at the position shown in FIG. Therefore, the throttle lever 4 is not engaged with the starting cam 7 and the fast idle cam 6
And the idle operation or the traveling operation is performed without the throttle valve being greatly opened.

[0011]

At extremely low temperatures (about -20.degree. C. or less), since the engine friction and the like are large, the throttle opening during cranking is set to be larger than at low temperatures (about -15.degree. C.). There is a need to.

However, in the above conventional structure, in order to make the throttle opening sharply open at a very low temperature, that is, to make the throttle opening characteristic with respect to the temperature sharply rise from the point B in FIG. It is necessary to rapidly change the shape of the cam surfaces 6a, 7a of the fast idle cam 6 or the starting cam 7, and it is difficult to design the cam surfaces, and the cam surfaces of the rising portions are easily worn. For this reason, the conventional structure described above does not cope with extremely low temperatures, and there is a problem that the startability of the engine at extremely low temperatures is poor.

In the present invention, therefore, the conventional cam is used from normal temperature to a predetermined low temperature, and at a very low temperature, the throttle lever is controlled by means separate from the above-mentioned cam so that the low temperature can be obtained. It is an object of the present invention to provide a device for improving the startability of an engine.

[0014]

According to a first aspect of the present invention, there is provided a carburetor having a fast idle cam for controlling the rotation of a throttle lever. Shaft (20
a) is provided so as to face the throttle lever (4), and the shaft (20a) is protruded at extremely low temperatures to rotate the throttle lever (4) in the opening direction. is there.

In the present invention, in a temperature range other than extremely low temperatures, when a fast idle cam or a starting cam is provided, the rotation of the throttle lever (4) is controlled by both cams, and the throttle valve (3) is adapted to the temperature. Is controlled to the appropriate opening degree.

At extremely low temperatures, the shaft (20a) of the actuator (20) protrudes, and the throttle lever (4) is largely rotated in the opening direction regardless of the fast idle cam or the starting cam.

According to a second aspect of the present invention, in a carburetor having a fast idle cam for controlling rotation of a throttle lever, an actuator (20) formed of an electromagnetic valve is connected to a throttle lever (4) by a shaft (20a) moving forward and backward. A temperature sensor (22) provided so as to face the other, and separately detecting the temperature of the cooling water of the engine; and the actuator (20) when the temperature sensor (22) detects a very low temperature when the ignition switch (23) is turned on. An electronic control unit (21) for exciting the actuator, and an actuator (20)
The shaft (20a) protrudes by the excitation of (1), and the throttle lever (4) is turned directly in the opening direction.

In the present invention, the opening and closing of the throttle valve (3) is controlled in a temperature range other than the extremely low temperature similarly to the first invention. At a very low temperature, when the temperature sensor (22) detects a very low temperature when the ignition switch (23) is turned on, this is detected by the electronic control unit (21), and the actuator (20) formed of a solenoid valve is excited. By this excitation, the shaft (20a) protrudes and pushes the throttle lever (4) directly in the opening direction, the throttle lever (4) pivots largely in the opening direction, and the throttle valve (3) is set to a predetermined temperature required at extremely low temperatures. It is opened to the opening degree.

When the temperature reaches a temperature other than the extremely low temperature, the excitation to the actuator (20) is cut off and the shaft (20) is turned off.
In a), the vehicle returns and returns.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described based on an embodiment shown in FIGS. FIG. 1 shows a main part according to the present invention, in which reference numeral 20 denotes an actuator composed of an electromagnetic valve, reference numeral 21 denotes an electronic control unit (ECU), reference numeral 22 denotes a temperature sensor for sensing the temperature of engine cooling water, and reference numeral 23 denotes an ignition switch. .

This embodiment is obtained by adding the components 20, 21, 22, and 23 to the apparatus shown in FIG. 5, and the structure other than these components is the same as the structure shown in FIGS. Slightly different in shape and the like). Therefore, the same reference numerals as those described above denote parts corresponding to the parts in FIG. 5, and a description of the structure will be omitted. Further, it also has the starting cam 7 and the solenoid valve 16 shown in FIG. 5, but these are omitted in the drawing.

The actuator 20 composed of a solenoid valve is disposed so as to oppose the shaft 20a such that the tip 20b of the shaft 20a engages with the side of the pin 4a provided at the lower end of the throttle lever 4. Are protruded leftward from the state of FIG. 1, and are retracted to the position of FIG. 1 by the biasing force of the return spring 20b due to non-excitation. Shaft 2 during this excitation
The protrusion amount of 0a is a predetermined cryogenic temperature (−23 ° C. in this embodiment).
In the following, the opening is set to be larger than the throttle opening by the starting cam 7 in the conventional device. In the embodiment, the throttle valve opening is set to 1 by the protrusion of the shaft 20a.
The angle is set to 5 degrees (see FIG. 9).

The electronic control unit 21 receives a signal from the temperature sensor 22 and a signal from the ignition switch 23. When these signals are input, the electronic control unit 21 emits a signal for exciting the actuator 20. It has become.

When the ignition switch 23 is turned on, it issues a command signal to the electronic control unit 21. The temperature sensor 22 senses the temperature of the cooling water of the engine, and when the temperature becomes extremely low, for example, -23.degree. A command signal is issued to the control unit 21.

Next, the operation will be described. The opening / closing control of the throttle valve 3 in the range of the temperature of the engine cooling water from normal temperature to around -23 ° C. is performed by the above-mentioned conventional cam structure in the same manner as the above-mentioned conventional one. The fuel ratio is properly maintained. In this temperature range, the command signal from the temperature sensor 22 is not input to the electronic control unit 21, so that the actuator 20
The shaft 20a is retracted as shown in FIG. 1 to a position where the full closing operation of the throttle valve 3 is not hindered by the urging force of the return spring 20b.

When the temperature of the cooling water is extremely low,
It operates as shown in the flowchart of FIG. That is, when the ignition switch 23 is turned on, the temperature sensor 22 senses the temperature of the cooling water, and when the electronic control unit 21 determines that the temperature is −23 ° C. or less, the excitation signal is sent to the actuator 20 which is an electromagnetic valve. And the actuator 20 is excited, and its shaft 20a projects as shown in FIG. 2 against the urging force of the return spring 20b. As a result, the tip 20b pushes the pin 4a, and the throttle lever 4 rotates in the opening direction as shown in FIG. 2 irrespective of the fast idle cam 6 and the starting cam 7, thereby turning the throttle valve 3 to an extremely low temperature of -23.degree. It opens widely to the required opening sometimes. FIG. 9 shows a state in which the points A to A are opened by the actuator 20. In the embodiment, the opening of the point A is 15 degrees.

Then, cranking is performed based on the throttle opening and the engine is started. Since the engine is warmed up after a predetermined time has elapsed after the start of the engine, it is necessary to return the throttle valve 3 to the opening control by the fast idle cam 6 and the starting cam 7.

Therefore, the excitation signal to the actuator 20 is cut off from the electronic control unit 21 after a lapse of a predetermined time from the start, the actuator 20 is turned off, and the shaft 2 is turned off.
0a by the biasing force of the return spring 20b.
Retreat like. Thus, the throttle lever 4 can be controlled by the fast idle cam 6 and the starting cam 7.

In the above embodiment, the operating temperature of the actuator 20 is set to -23 ° C. or lower. However, the operating temperature is not limited to this and may be set as desired. The angle is not limited to 15 degrees in the embodiment, but may be set as desired.

Further, the present invention is not limited to the one applied to the above-mentioned conventional structure.
The present invention may be applied to a system in which a throttle valve is controlled in accordance with a temperature only by a fast idle cam without using a start cam as shown in No. 828.

[0031]

As described above, according to the present invention,
In a temperature range other than cryogenic temperature, the opening of the throttle valve can be appropriately controlled in accordance with the temperature by a normal fast idle cam or a starting cam as in the conventional case. Open to enhance the startability of the engine.

In addition, since the opening operation of the throttle valve particularly at the extremely low temperature is performed by projecting the shaft provided on the actuator so as to face the throttle shaft, the opening operation is performed on the cam surface. Compared with the conventional one, the rapid opening operation (sudden rising operation) of the throttle valve is facilitated, and there is no difficulty in designing the cam surface as in the related art.

Accordingly, stable startability of the engine from normal temperature to extremely low temperature in combination with the conventional cam control can be easily obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the present invention, showing a state other than when the temperature is extremely low.

FIG. 2 is a sectional view showing a state at the time of extremely low temperature.

FIG. 3 is a cross-sectional view showing a state where the shaft of the actuator is retracted after the cryogenic start.

FIG. 4 is a flowchart illustrating the operation of the present invention.

FIG. 5 is a partially cut-away side view showing a conventional structure.

FIG. 6 is a diagram illustrating an operation state.

FIG. 7 is a diagram illustrating an operating state.

FIG. 8 is a diagram illustrating an operating state.

FIG. 9 is a characteristic diagram showing a throttle opening degree with respect to a cooling water temperature.

[Explanation of symbols]

 3 Throttle valve 4 Throttle lever 20 Actuator 20a Shaft 21 Electronic control unit 22 Temperature sensor 23 Ignition switch

Claims (2)

[Claims] 1. A carburetor having a fast idle cam for controlling rotation of a throttle lever, wherein an actuator is provided such that a shaft that moves forward and backward is opposed to the throttle lever, and the shaft is protruded at an extremely low temperature. A starting and warming device for a carburetor, wherein a lever is rotated in an opening direction. 2. A carburetor having a fast idle cam for controlling rotation of a throttle lever, wherein an actuator comprising an electromagnetic valve is provided so that a shaft that moves forward and backward is opposed to the throttle lever. And an electronic control unit that excites the actuator when the temperature sensor detects extremely low temperature when the ignition switch is turned on, and when the actuator is excited, its shaft protrudes and the throttle lever is directly opened. A starting and warming-up device for a carburetor, which is rotated.