JP3154512B2 - Fuel increase system for starting marine engines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for increasing the amount of fuel for starting a marine engine, and more particularly to an improvement in a fuel supply line arrangement for increasing the amount of fuel at the time of starting the engine.

[0002]

2. Description of the Related Art Conventionally, a fuel increase supply device for starting a marine engine supplies an increased amount of fuel when starting the engine in order to improve the startability of the engine. As a conventional example of a fuel supply system provided with such a fuel increasing supply device for starting, there is one described in, for example, JP-A-56-20739. In this conventional example, in addition to the main fuel supply line extending from the primary pump to the carburetor float chamber, a fuel increase supply line for increasing the amount of fuel at the time of starting the engine is provided, and in the middle of the fuel increase supply line. A pump for increasing the amount of starting fuel is provided, and the increased amount of supplied fuel is obtained from the carburetor float chamber.

[0003]

However, in the conventional apparatus, since the fuel to be supplied in an increased amount is obtained from the carburetor float chamber, the priming pressure by the primary pump is supplied from the carburetor float chamber. It does not extend to the pipeline and the starting fuel supply pump. Therefore,
If air bubbles accumulate in the fuel increase supply pipe, it becomes extremely difficult to release air from the pipe, and the start-up fuel supplied in an increased amount is blocked by the air bubbles. In particular, if air bubbles are present near the inlet of the starting fuel increasing supply pump, even if the pump is operated, only the air bubbles are supplied for a while, and it takes time until the necessary increased fuel is supplied. There is a problem that the amount of fuel supplied from the fuel supply pump for starting is increased when the engine is started.

Accordingly, the present invention has been made in view of such problems, and an object of the present invention is to provide a fuel increaser for a marine engine which can stably supply a larger amount of fuel when the engine is started. To be.

[0005]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a main fuel supply line for supplying fuel to a carburetor float chamber and an engine start branching off from the main fuel supply line. A fuel supply line for supplying additional fuel at times, and a starting fuel supply pump provided in the middle of the fuel supply line, and the fuel supply pipe upstream of the fuel supply pump. The passage is arranged at a position higher than the fuel supply pump inlet.

[0006]

According to this structure, since the upstream side of the starting fuel increasing pump of the fuel increasing supply pipe is disposed at a position higher than the starting fuel pump inlet, the starting fuel increasing supply pump inlet is provided. Bubbles in the vicinity can be raised in the fuel increase supply pipe by buoyancy. Since the fuel supply line is branched from the main fuel supply line, air bubbles that have risen in the fuel supply line due to buoyancy reach the main fuel supply line, and the main fuel supply line is generated by the priming pressure. Removed from the road. As a result, bubbles do not accumulate at the inlet of the fuel supply pump for start-up, and the fuel in the fuel supply pipe can be stably supplied without being interrupted by the bubbles. The required amount of fuel can be secured, and the startability of the engine can be greatly improved.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments shown in the drawings.

FIG. 1 shows an outboard motor provided with an embodiment of a fuel increase supply device according to the present invention. Outboard motor 1
No. 0 has a configuration in which an engine body 16 is provided in a cowling composed of a top cowl 12 and a bottom cowl 14. The engine body 16 is mounted on a propulsion unit 18. The propulsion unit 18 is mounted on a stern plate 20 of a hull via a swivel bracket 22, and the swivel bracket 22 is pivotally supported by a tilt shaft 24. The outboard motor can rotate up and down around the tilt shaft 24 as shown by a dashed line in FIG.

Reference numeral 26 denotes a primary pump located in front of the outboard motor, and the primary pump 26 is connected to a main fuel supply line (hereinafter, referred to as a "main fuel line") 28. The main fuel line 28 is connected to the bottom cowl 14.
Heading into the cowling from the lower front of the
6 is piped along its bottom surface. The main fuel line 28 rises substantially vertically in a rear portion inside the engine main body, then bends at a right angle in a forward direction inside the engine main body, and has a filter 30 in the middle.

Further, the main fuel line 28 descends at right angles in the engine main body, and has a branch joint 32 on the way, through which fuel supply for increasing fuel supply at the time of engine start is provided. An upstream portion 34 of a pipe (hereinafter, referred to as “fuel-enhancing pipe”) is branched.

The fuel increase pipe 34 descends in the engine body and is connected to a fuel increasing supply pump (hereinafter, referred to as "fuel increase pump") 36 for starting. In the chamber of the fuel boosting pump 36, a diaphragm 38 serves as a partition to form a fuel chamber 40, and a support rod 42 is locked to one end of the diaphragm 38, and the other end of the support rod 42
A starting wire 44 is connected, and a knob 46 is fixed to an end of the starting wire 44.

A downstream portion 50 of the fuel-enhancing pipe extends from the fuel chamber 40 of the fuel-enhancing pump 36 and rises, and opens into the intake passage 48 of the cylinder. The pipe 50 is branched in the middle by the branch joint 51, and the branched fuel increase pipe 53 opens into the crank chamber 49.

The main fuel line 28 downstream of the branch joint 32
Is bent horizontally forward near the bottom inside the engine body,
Next, it is raised toward and connected to a main fuel supply pump (hereinafter, referred to as “main fuel pump”) 52 located above. The other end of the main fuel pump 52 is connected to an elbow 54 that constitutes a part of the main fuel line.
The other end of the elbow 54 is connected to a branch joint 56 and is branched into a first fuel supply pipe 58 toward the upper cylinder and a second fuel supply pipe 60 toward the lower cylinder. First
The fuel supply line 58 is connected to the first vaporizer float chamber 62, and the second fuel supply line 60 is connected to the second vaporizer float chamber 64. Reference numeral 55 denotes a pipeline for supplying a pressure inside the crankcase to the fuel pump 52 to cause a pump operation.

Next, the operation of this embodiment will be described. The fuel supplied to the main fuel line 28 by the primary pump 26 is purified in the filter 30 and then reaches the main fuel pump 52. The fuel is then supplied to the first fuel supply line 5
8 and the second fuel supply line 60, respectively,
To the second vaporizer float chamber 62 and the second vaporizer float chamber 64.

In the branch joint 32, the main fuel line 28
A part of the fuel inside the fuel tank is divided, and the divided fuel is supplied to the fuel-enhancing pipe 34.
Inside. When the knob 46 is pushed and pulled in the front-rear direction at the time of starting the engine, the internal pressure in the fuel chamber 40 is changed by the diaphragm 38 in the fuel-enhancing pump 36,
As a result, an increased amount of fuel is supplied from the fuel-enhancing pipe 34 upstream of the pump 36 to the intake passage 48 and the crank chamber 49 via the fuel-enhancing pipe 50 downstream of the pump 36. You.

Referring further to FIG. 2, in the present embodiment, the fuel-enhancing line 34 descends toward the fuel-amount increasing pump, and the fuel-enhancing line 34 on the upstream side of the fuel-enhancing pump 36 increases. It is located higher than the fuel pump fuel inlet,
Assuming that the height up to the oil level of the filter 30 with respect to the fuel inlet 37 is h1 and the height up to the branch joint 32 is h2,
It is configured such that h1> h2. Therefore, air bubbles existing in the fuel-enhancement pump inlet 37 or the fuel-enhancement line 34 when the engine is stopped rise to the main fuel line 28 through the upper branch joint 32 due to buoyancy acting on the air bubbles.

As a result, no bubbles are present in the fuel-enhancing pipe 34, and the fuel can be stably supplied to the fuel-enhancing pipe 34 in an increased amount without being interrupted by the air bubbles. Even if air bubbles enter the fuel-enhancing pump inlet 37 of the fuel-enhancing pipe 34, the air bubbles rise in the fuel-enhancing pipe due to buoyancy, and the fuel near the fuel-enhancing pump inlet 37 is always filled with fuel. Can be secured. Therefore, when the fuel-increase pump 36 is operated, the fuel is immediately supplied into the engine, and the fuel can be stably increased at the time of starting the engine.

The bubbles that have risen are supplied to the intake passage after a sufficient amount of starting fuel has been supplied, or removed from the system via the main fuel line 28 after the engine has been started.
Therefore, it is possible to eliminate the influence of the bubbles on the next engine start.

In this way, since the air bubbles are effectively removed from the fuel-enhancing line 34, the fuel can be stably increased and supplied from the fuel-enhancing line 34 at the time of starting the engine.
The startability of the engine can be greatly improved.

Next, a case where the outboard motor is tilted up will be described. FIG. 3 shows this state, and even when tilted up, the fuel-enhancing pipe 34 is formed at a position higher than the fuel inlet 37, and the oil level of the filter 30 is determined based on the fuel inlet 37. And the height up to the branch joint is set to H2 so that H1> H2, so that even in the tilt-up state, the bubbles in the fuel-enhancing pipe 34 rise due to buoyancy, and the fuel-enhancing pipe 34 Bubbles inside can be removed via main fuel line 28. As described above, in the present embodiment, regardless of the attitude of the outboard motor, the startability of the engine can be greatly improved by always stably supplying a large amount of fuel when the engine is started. Can be improved.

In the present embodiment, air bubbles in the fuel-enhancing line 34 are configured to escape to the main fuel supply line 28. However, an inverted U-shaped portion exists in the fuel-increasing line, Even if bubbles remain in the inverted U-shaped top portion, the startability of the engine is not reduced. That is, even if bubbles are present at the fuel-enhancement pump inlet 37, if the fuel-enhancement pipe 34 is disposed at a position higher than the inlet 37, the bubbles rise to the top in the inverted U-shape. As described above, since fuel is present in the fuel increasing conduit 34 from the inverted U-shaped top to the pump inlet 37, the fuel can be supplied in an increased amount at the time of starting the engine, and the startability of the engine can be improved. Since the fuel increase pipe 34 branches off from the main fuel supply pipe 28 to which the priming pressure of the primary pump 26 is applied, the priming pressure can also be applied to the fuel increase pipe 34. Therefore, when the engine is started, the priming pressure and the change in the internal pressure of the fuel chamber 40 of the fuel-enhancing pump are combined to allow the air bubbles in the fuel-enhancing pipe 34 to escape into the intake passage 48 via the fuel-enhancing pump. .

According to the present embodiment, since the fuel increased from the fuel booster pump is not introduced from the carburetor float chamber as in the prior art, the fuel oil level in the carburetor float chamber is lowered, or The vaporizer float chamber does not become empty.

[0023]

As described above, according to the present invention, since the fuel increasing pipe upstream of the fuel increasing supply pump is arranged at a position higher than the fuel increasing supply pump inlet, the engine Fuel can be supplied stably at start-up,
There is an excellent effect that the engine startability can be greatly improved.

[0024]

[Brief description of the drawings]

FIG. 1 is a side view of an entire outboard motor provided with an embodiment of a fuel increasing device according to the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is an enlarged view of FIG. 1 in a tilt-up state.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Outboard motor 16 Engine main body 26 Primary pump 28 Main fuel supply line 32 Branch joint 34, 50 Fuel increase supply line 36 Fuel increase supply pump for engine start 52 Main fuel supply pump

Claims (1)

(57) [Claims] 1. A main fuel supply line for supplying fuel to a carburetor float chamber, a fuel increase supply line branched from the main fuel supply line and supplying an increased amount of fuel at the time of engine start, and a fuel increase supply A starting fuel increasing supply pump provided in the middle of the pipe, wherein the fuel increasing supply pipe on the upstream side of the fuel increasing supply pump is disposed at a position higher than the fuel increasing supply pump inlet. Fuel increase device for starting ship engines.