JP2997896B2 - Engine starter with diaphragm carburetor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an engine starting device provided with a diaphragm type carburetor.

[Conventional technology]

Diaphragm carburetors, which are generally used for engines such as brush cutters and chain saws, have good inclination and are most suitable for these engines, but this carburetor will almost empty the fuel in the diaphragm chamber after the engine stops. Therefore, it is necessary to fill the diaphragm chamber with fuel at the next start.

Therefore, conventionally, by attaching a starting pump to the carburetor and operating this starting pump before starting the engine,
A mechanism for introducing fuel into the diaphragm chamber is employed. (Refer to Japanese Utility Model Publication No. 51-43315 and Japanese Patent Application Laid-Open No. Sho 55-69748.) In order to start the engine, it is necessary to increase the concentration of the air-fuel mixture. In order to supply a desired rich air-fuel mixture to the engine, the intake air amount is further restricted by closing a choke valve. It is necessary to.

[Problems of the prior art]

As described above, in the related art, when starting the engine, it is necessary to perform the choke operation following the operation of the starting pump, and these operations are very troublesome.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an engine starting device provided with a diaphragm carburetor which is easy to start and has good startability.

[Means for solving the problem]

The present invention provides a pressurizing pump which presses the recoil starter and pressurizes air when pushed by a rope of the starter,
The sub-diaphragm moves by receiving air sent from the pressurizing pump, pushes up the metering diaphragm of the carburetor and opens the fuel valve, and leaks the pumped air to the atmosphere according to the temperature of the engine. A temperature-sensitive valve for controlling the amount of movement and the time of movement is provided.

[Action]

Pull the recoil starter to start the engine,
The pressurizing pump is pushed by the rope of the recoil starter, and air is pumped. The sub-diaphragm moves in response to the air pressure sent from the pressurizing pump to push up the metering diaphragm and open the fuel valve. The fuel pump of the carburetor is driven by the cranking of the engine, and the fuel sucked from the fuel tank flows into the diaphragm chamber through the opening of the fuel valve, and is ejected to the intake passage through the nozzle. When the recoil starter returns, the pressing of the pressurizing pump is released, so that the sub-diaphragm moves downward, the fuel valve is closed, and the injection of fuel into the intake passage is stopped. Therefore, fuel is ejected only when the recoil starter is pulled, that is, only during cranking of the engine.
As a result, the intake and ignition of the fuel into the engine are improved, and the startability of the engine is improved.

〔Example〕

 Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an explanatory view of a starting device of the present invention, and FIG. 2 is an explanatory view of a main portion showing another embodiment of the starting device of the present invention.

Reference numeral 1 denotes a diaphragm carburetor, which is provided with an intake passage 3 penetrating through the body 2, an upstream side of the intake passage 3 is connected to an air cleaner (not shown), and a downstream side is connected to an intake port of an engine (not shown). ing. A throttle valve 4 for changing the effective aperture of the intake passage 3 is provided in the intake passage 3.
Are arranged. A fuel nozzle 5 is opened in the intake path wall below the throttle valve 4, and the other end of the fuel nozzle 5 is connected to a diaphragm chamber 6.

Reference numeral 10 denotes a fuel pump driven by the operating pressure of the engine. The fuel pump 10 is a well-known diaphragm pump including a pump diaphragm 11 and a pair of check valves 12 and 13, and is a part of the pump diaphragm 11. The pump diaphragm 11 is vibrated by applying the operating pressure of the engine to the pressure chamber 14 formed on the other side, and the fuel is formed on the other side of the pump diaphragm 11 from the fuel tank 15 through one check valve 12. The pressure is sucked into the pump chamber 17 and the pressure is sent from the other check valve 13 to the diaphragm chamber 6 through the fuel passage 18.

At the entrance of the diaphragm chamber 6 of the fuel passage 18, in order to interrupt the passage 18 in relation to the metering diaphragm 19,
That is, there is provided a fuel valve 20 which operates to interrupt communication between the fuel pump 10 and the diaphragm chamber 6.
A lever 22 having a support shaft 21 is arranged between the fuel valve 20 and the metering diaphragm 19. The lever
Reference numeral 22 denotes one side of the support shaft 21 connected to the fuel valve 20 and the other side connected to the metering diaphragm 19.
Accordingly, when a strong intake negative pressure acts on the diaphragm chamber 6 through the fuel nozzle 5, the metering diaphragm 19 causes the fuel valve 20 to move through the lever 22 to introduce fuel into the diaphragm chamber 6. The passage 18 is held at the open position. When the strong negative pressure in the diaphragm chamber 6 is extinguished by the introduction of fuel into the diaphragm chamber 6, the fuel valve 20 is compressed by a compression spring 23 engaged with the lever 22.
The passage 18 is blocked to prevent the introduction of fuel into the diaphragm chamber 6 by the biasing force.

A sub-diaphragm 25 is provided below the metering diaphragm 19, and an upper side of the sub-diaphragm 25 is an air chamber.
On the lower side, a pressure chamber 27 is formed. A rod 28 is attached to the sub-diaphragm 25 and protrudes toward the atmosphere chamber 26 to push up the metering diaphragm 19, and urges the sub-diaphragm 25 toward the pressure chamber 27 in the atmosphere chamber 26. A spring 29 is provided.

Reference numeral 31 denotes a pressurizing pump, in which a diaphragm 33 is stretched in a casing 32, and a pump chamber 34,
An atmosphere chamber 35 is formed on the other side, and the diaphragm 33 is
A rod 36 projecting toward the atmosphere chamber 35 is attached to the pump chamber 34, and a resilient spring 37 is further disposed in the pump chamber 34 to bias the diaphragm 33 in a direction in which the volume of the pump chamber 34 constantly increases. By pressing, the air in the pump chamber 34 is pushed out. Further, the tip of the rod 36 is projectedly engaged with a rope 39 of a recoil starter 38 so as to bend a part of the rope 39, and when the recoil starter 38 is pulled, the rod 36 is pushed by the rope 39, and a pump is provided. The air in the chamber 34 is sent under pressure.

The pump chamber 34 is connected to the pressure chamber 27 by an air supply passage 41.
It is connected to the. Therefore, when the recoil starter 38 is pulled, that is, when cranking of the engine is performed, air pumped from the pump chamber 34 flows into the pressure chamber 27 to move the sub-diaphragm 25 upward, and push up the metering diaphragm 19. Open the fuel valve 20.

On the other hand, when the recoil starter 38 returns, that is, when cranking of the engine is not performed, the pressing of the rod 36 is released and the diaphragm 33 returns to the normal position by the action of the elastic spring 37. As a result, the pressure in the pressure chamber 27 disappears, the sub-diaphragm 25 descends, and the fuel valve 20 is closed.

A temperature sensing valve 43 is provided on the air supply passage 41 and opens when the engine temperature is high and opens the passage 41 to the atmosphere through a leak hole 42. Therefore, when the engine temperature is high, a part of the pumped air is discharged to the atmosphere, the upward movement amount and the pushing time of the sub-diaphragm 25 are reduced, and the fuel amount injected into the intake passage 3 is reduced. Further, the temperature sensing valve 43 may be provided in the pressure chamber 27 or the pump chamber.

Reference numeral 45 denotes a leak hole communicating the pressure chamber 27 with the atmosphere. Although there is no particular need to provide the leak hole 45, the leak hole 45 is provided and adjusted when the return of the sub diaphragm 25 is slow or does not return when the recoil starter 38 returns.

 Next, the operation of the above embodiment will be described.

When the recoil starter 38 is pulled to start the engine, the rod 36 of the pressurizing pump 31 is pushed by the rope 39, the diaphragm 33 moves, and the air in the pump chamber 34 is sent to the pressure chamber 27 by pressure. This air pressure moves the sub-diaphragm 25,
Push up the vaporizer metering diaphragm 19 and fuel valve 20
open. The fuel pump 10 of the carburetor is driven by the cranking of the engine, and the fuel sucked from the fuel tank 15 flows into the diaphragm chamber 6 through the opening of the fuel valve 20 and is ejected from the nozzle 5 to the intake passage 3. . When the recoil starter 38 returns, the pressure of the pressurizing pump 31 is released, so that the fuel valve 20 is closed and the injection of fuel into the intake passage 3 is stopped. Therefore, fuel is injected only when the recoil starter 38 is pulled, that is, only during cranking of the engine. As a result, the intake and ignition of the fuel into the engine are improved, and the startability of the engine is improved.

When the engine is warmed up, the temperature sensing valve 43 opens,
The air sent from the pressure pump 31 is leaked to the atmosphere through the leak hole 42, the amount of air sent to the pressure chamber 27 and the holding time of the air are reduced, and the metering diaphragm 19
The push-up amount and push-up time. As a result, the amount of fuel injected into the intake passage 3 is reduced, and the start during warm-up is improved.

Also, when the internal pressure of the fuel tank 15 is high, excessive fuel is ejected into the intake passage 3 when the fuel valve 20 is opened, and therefore, as shown in FIG. The atmosphere 33 and the upper air layer of the fuel tank 15 are closed by a pipe 48 so that the diaphragm 33 of the pressurizing pump 31 is moved to the pump chamber 34 in accordance with the internal pressure of the fuel tank 15. It is possible to reduce the amount of air pumped during operation of the recoil starter 38, reduce the opening of the fuel valve 20 of the carburetor, and reduce the amount of fuel injected into the intake passage 3 by moving the volume in the direction of decreasing the volume. it can.

〔The invention's effect〕

As described in detail above, according to the present invention, a pressurizing pump that is driven only when the recoil starter is pulled is provided, and the fuel valve is pushed up by the metaling diaphragm by air pressure fed from the pressurizing pump. By providing the sub-diaphragm that opens, the fuel valve is opened only during the pulling operation of the recoil starter, that is, during engine cranking, and the fuel supplied from the fuel pump is ejected to the intake passage. The ignition plug is ignited in the engine and the fog of the ignition plug is eliminated, and the startability is improved. Further, unburned gas is not released to the atmosphere.

Further, according to the present invention, since the engine can be started only by pulling the recoil starter, the starting operation becomes very simple.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a starting device of the present invention, and FIG. 2 is an explanatory view of a main portion showing another embodiment of the starting device of the present invention. 1 ... diaphragm carburetor, 3 ... intake path, 19 ... metering diaphragm, 20 ... fuel valve, 25 ... sub-diaphragm, 27 ... pressure chamber, 31 ... pressure pump, 38 ... recoil Starter, 39 ... rope.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-62-75058 (JP, A) JP-A-63-9661 (JP, A) JP-A-2-45645 (JP, A) 128377 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) F02M 1/16, 17/04 F02N 3/02

Claims (1)

(57) [Claims] 1. A pressurizing pump for pushing air supplied by a rope of a starter when a recoil starter is pulled;
The sub-diaphragm moves by receiving air sent from the pressurizing pump, pushes up the metering diaphragm of the carburetor and opens the fuel valve, and leaks the pumped air to the atmosphere according to the temperature of the engine. A starting device for an engine equipped with a diaphragm type carburetor, comprising a temperature sensing valve for controlling a moving amount and a moving time.