JPS6039468Y2 - Plunger type automatic starting device for carburetor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an automatic starting device for a plunger-type starting device for a carburetor that automatically adjusts the opening and closing of the starting plunger using a temperature-sensitive actuation device based on the engine temperature.

Conventionally, in this type of starting device, the starting plunger opens and closes depending on the engine temperature, so after starting the engine, until the engine is sufficiently warmed up (until the temperature-sensitive actuating device is activated), the rich mixture at the time of starting is maintained. is supplied at that time, resulting in an overly rich mixture for warm-up, which is not really desirable from the standpoint of smooth engine operation or exhaust gas purification.

The present invention is an automatic starting device that adjusts the opening and closing of a starting plunger using a temperature-sensitive actuation device based on the machine temperature.A negative pressure chamber is provided above the starting plunger and communicates with the engine suction pipe, and the device is operated by the negative pressure in the negative pressure chamber. The plunger is actuated by the diaphragm, which has a primary push-up spring (spring that fully opens the starting mixture passage) and the diaphragm when the plunger partially opens the starting mixture passage. The object of the present invention is to provide an automatic starting device that eliminates the problems of the above-mentioned conventional starting devices by including a secondary push-up spring that is compressed in advance to provide an operating resistance. This will be explained with reference to the embodiment diagrams.

FIG. 1 is a sectional view of one embodiment of the present invention, showing only the starter portion.

Reference numeral 1 denotes a starter main body which is generally formed integrally with the carburetor main body, 2 a starting air passage 3 leading from the air intake port (not shown) of the carburetor intake cylinder, and a secondary side of the carburetor throttle valve (not shown). 6 is a sliding boss of the plunger 2, which opens and closes the starting air-fuel mixture supply passage 4 communicating with the intake pipe side) and the starting fuel passage 5 communicating from the carburetor fuel chamber (not shown); 7 is a plunger operating rod that is integrated with the plunger 2.

8 is a negative pressure chamber connected to an engine suction pipe (not shown) and a negative pressure communication passage 9
will be communicated with.

A diaphragm 10 is installed in the upper part of the negative pressure chamber 8, and is pulled down by the negative pressure of the negative pressure chamber 8, but normally the starting plunger 2 fully opens the starting mixture supply path 4 by the primary push-up spring 11. It is being pushed up as well.

12 is a spring holder for the spring 11.

Further, a lower spring receiver 14 is slidably fitted under the plunger operating rod 7 with a slight gap between the upper surface 13 of the plunger boss 6 and the lower spring receiver 14.
A secondary push-up spring 15 of the diaphragm 10 is inserted between the diaphragm 10 and the spring receiver 12 in a compressed state.

That is, when the illustrated starting plunger 2 is slightly lowered from the fully open position to slightly open the starting air-fuel mixture supply path 4, the lower spring 14 comes into contact with the upper surface 13 of the plunger boss 6.
After that, when the diaphragm 10 is lowered, the starting plunger 2 can be lowered against both the primary push-up spring 11 and the secondary push-up spring 15.

16 is an atmospheric chamber, 17 is a temperature-sensitive actuation device 20 based on engine temperature.
The actuation wire of the diaphragm 10 is guided from the diaphragm 10.

In the temperature-sensitive actuating device 20, reference numeral 21 denotes a temperature-sensitive wax, and the temperature-sensitive wax 21 is attached to, for example, an exhaust pipe or a cylinder cooling tube in the engine cylinder head configuration so as to sensitively sense the engine temperature.

With the above configuration, when the engine is cold, the starting plunger 2 is pushed up by the primary push-up spring 11 to fully open the starting mixture supply path 4, and after the phase is warmed up, The actuating wire 17 presses the diaphragm 10 to close the plunger 2 according to the engine temperature, but during the period after the complete explosion of the engine until it warms up, that is, during slow speed operation for warming up,
The suction tube negative pressure acts on the negative pressure chamber 8 and pulls down the diaphragm 10, thus lowering the plunger 2 and diluting the supplied mixture.

In this way, the plunger 2 is lowered by the negative pressure in the negative pressure chamber 8, but when the lower spring receiver 14 comes into contact with the upper surface 13 of the plunger boss 6, the drag force of the secondary push-up spring 15 is applied to the diaphragm 10. Since the secondary push-up spring 15 is already slightly loaded, the lowering of the diaphragm is temporarily stopped at that position.

Therefore, if the plunger position where the lower spring receiver 14 of the plunger comes into contact with the plunger boss upper surface 13 is set to the proper mixture supply position for warming up the engine, the proper mixture will be maintained after the engine has completely exploded. The warm-up air-fuel mixture is supplied at a specific temperature.

Then, as the engine warms up, the wire 17 is activated by the temperature-sensitive actuating device 20 to press the diaphragm 10, thereby depressing the plunger 2, thereby supplying an air-fuel mixture according to the engine temperature.

As described below, the starting device according to the present invention not only supplies a rich mixture at the time of starting and adjusts the supplied mixture as the engine warms up after starting, but also adjusts the supplied mixture until the engine warms up after starting. This system automatically adjusts the temperature to the correct warm-up mixture.

Furthermore, a starting device as shown in FIG. 2 has also been devised, which is activated by negative pressure in the suction pipe and uses a double coil spring as a spring for pushing up the diaphragm that presses the starting plunger. There is.

In the figure, 15' is a secondary push-up spring, and when the primary push-up spring 11 is fully pushing up the diaphragm 10 (when the plunger 2 is fully opened), the spring 15' is connected to the spring receiver 12'. A gap a is provided between the lower surface and the upper surface of the secondary push-up spring 15', that is, after the engine starts, the diaphragm 10 is pulled down by the suction pipe negative pressure and the supply air-fuel mixture is moved to the position lowered by the amount a. Set the plunger to the warm-up mixture.

Therefore, in this position, the secondary push-up spring 15' is applied to the diaphragm.
Since the load is applied, the operation of the plunger 2 is temporarily stopped.

However, in this case, since the pressing force of the diaphragm 10 applied to the spring 15' is an initial pressure, the action of temporarily stopping the operation of the plunger 2 cannot be performed unless a slight strain is applied.

Therefore, the supply position of the warm-up air-fuel mixture is determined by taking into account the distortion in the gap a, but it is difficult to accurately determine its size.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of an automatic starting device according to the present invention, and FIG. 2 is a diagram of a conventional device for a diaphragm push-up spring related to this type of starting device. 2... Plunger for starting 4... Mixture supply path for starting, 6... Plunger sliding boss, 7... Plunger operating rod, 8...
... Negative pressure chamber, 10 ... Diaphragm, 11 ... Primary push-up spring, 2 ... Spring receiver, 13 ... Plunger boss Upper surface, 14...Lower spring receiver, 15...Secondary push-up spring, 20...Temperature-sensitive actuation device.

Claims (1)

[Scope of utility model registration request] In a starting device for a carburetor that opens and closes a starting plunger 2 using a temperature-sensitive actuating device 20 based on the engine temperature, a negative pressure chamber 8 communicating with an engine suction pipe is provided above the starting plunger 2, and the above-mentioned starting plunger Reference numeral 2 denotes a primary push-up spring 11 of a starting plunger 2 which is actuated by a diaphragm 10 operated by the negative pressure in the negative pressure chamber 8 and fully opens the starting air-fuel mixture supply path 4, and the diaphragm 10 and the starting plunger. The lower part of the plunger actuating rod 7 that connects the plunger actuating rod 7 with the plunger sliding boss 6 has a slight gap with the upper surface 13 of the plunger sliding boss 6. It is characterized by comprising a lower spring receiver 14 that comes into contact with the upper surface 13 of the plunger sliding boss when the plunger is slightly lowered, and a secondary push-up spring 15 that is compressed and inserted into the upper part of the lower spring receiver 14. Plunger type automatic starting device for carburetor.