JPS593155A - Gas fuel engine fuel supply system - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fuel supply system for a gaseous fuel engine that uses only gaseous fuel or a combination of gaseous fuel and liquid fuel.

By the way, the supply of gaseous fuel in this type of engine can be done by injecting fuel mixed with air at a predetermined air-fuel ratio into the combustion chamber through an intake valve, or by providing gaseous fuel in each combustion chamber separately from intake and exhaust valves. According to the former method, fuel is supplied by a fuel supply valve, etc.
During the overlap period when both the intake and exhaust valves open during the transition from the exhaust stroke to the intake stroke, a portion of the fuel mixed with air that is drawn into the combustion chamber is directly discharged from the exhaust valve, and is discharged into the exhaust pipe or into the engine. There is a risk of external combustion. In addition, in the latter supply method, the amount of air taken into each combustion chamber differs depending on the arrangement position of the cylinders, etc., so if fuel is uniformly supplied to each combustion chamber, the air fuel consumption will differ for each cylinder. This leads to deterioration in drivability due to variations in combustion conditions.

The present invention deals with the above-mentioned problems in gas fuel engines. A fuel supply valve is installed on the gas fuel supply path to each combustion chamber, and the valve is controlled by a cam at a predetermined timing via a rocker arm. In the fuel supply device configured to open and close, the lever ratio of the rocker arm can be arbitrarily adjusted, so that the opening degree of the fuel supply valve can be freely adjusted with respect to a cam of a fixed shape. This makes it possible to supply each combustion chamber with an amount of fuel corresponding to the intake air amount of that cylinder, thereby preventing variations in the combustion state due to differences in air-fuel ratio.

Hereinafter, the present invention will be explained based on the embodiment shown in the drawings. In FIG. 1, 1 is a combustion chamber formed by a cylinder frame 2, a cylinder head 3, and a piston 4; Formed fuel supply path 5
One end of the supply path is open, and a gaseous fuel supply pipe 6 is connected to the other end of the supply path. Reference numeral 7 denotes a fuel supply valve that opens and closes the opening of the fuel supply path 5 to the combustion chamber fillet, and is normally biased in the closing direction by a spring 8, and is closed by a fuel cam (not shown) on the camshaft. Butsch rod 9
, the main rocker arm 10 and the auxiliary rocker arm 11 are configured to be opened against the spring 8 at a predetermined time (an appropriate time during the period when only the intake valve is open). 12 is a swing shaft of the main rocker arm 10; 13 is a bracket that swingably supports the rocker arm via the shaft; the swing shafts 12 are eccentric to each other as shown singly in FIG. It has a large diameter part 14 and small diameter parts 15.15 on both sides thereof, and the large diameter s14 is fitted into a fitting hole 16 formed in the main rocker arm 10,
A small diameter portion 15.15 is rotatably supported on the bracket 13. However, the large diameter portion 1 of the swing shaft 12
A flat part 14a is formed on the upper part of the main rocker arm 10, and the tips of two screws 17 and 17 screwed from the upper end surface of the main rocker arm 10 are located at positions sandwiching the center line X of the flat part. The main rocker arm 10 and the swing shaft 12 are brought into contact with each other, so that the main rocker arm 10 and the swing shaft 12 are integrated, but if both the screws 17 and 17 are loosened, the main rocker arm 10 and the swing shaft 12 are brought into contact with each other. It is possible to relatively rotate the screws 1 within a certain range by arbitrarily adjusting the phase of the two.
If 7.17 is tightened, the arm and the swing shaft will be fixedly integrated again with the adjusted phase relationship.

According to the above configuration, the main rocker arm 10 and the swing shaft 1
If the phase relationship of the large diameter portion 140 in 2 is set such that the flat portion 14a is located on the left side in the drawing, as shown by the solid line in FIG. The small diameter portion 15 of the swing shaft 12 is located to the right of the arm 10, and the plane flJr 14a is located to the right as shown by the chain line. If the shafts are integrated, the small diameter portion will be located relatively to the left, and by changing the phase relationship between the main rocker arm 10 and the swing shaft 12, the swing of the arm will be controlled. Small diameter part 1 that is the center
5 will move relatively, but since the position of the small diameter portion 15 is determined by the bracket 13, the main rocker arm itself will move from side to side. The ratio b/l of the distance a from the connection point A of the bushing rod 9 on the arm to the swing center xi and the distance from the center X to the point of action B on the fuel supply valve 7, that is, the lever ratio changes. It will become. As a result, for a constant lift amount of a cam (not shown), for example, compared to the case where the lever ratio is b/4 shown by the solid line in FIG. 3, when the lever ratio is b'/a' shown by the chain line, 97 The amount of fuel supply valve 7 becomes smaller, etc.
The opening degree of the combustion chamber can be set arbitrarily, and therefore the amount of gaseous solvent supplied to the combustion chamber can be adjusted.

The purpose of the auxiliary rocker arm 11 shown in FIG. 1 is to ensure that the opening force acts on the fuel supply valve 7 even if the point of application B of the main rocker arm 100 is displaced.
As shown in FIG. 4, instead of the auxiliary rocker arm, a cap 19 held movably up and down by a guide member 18 is installed above the health benefit donation valve 7, so that the point of action B of the main rocker arm 10 is always It may be made to abut on the upper end surface of the cap.

In addition, the embodiment shown in FIGS. 5 and 6 has a main rocker arm 1.
While fixing the lever ratio of 0', 10'', the action points of the arm B', B'' and the fuel supply valve 7'.

Auxiliary rocker arm 11' interposed between
, 11" lever ratio can be changed using the same configuration as in the above embodiment. As a result, the opening degree of the fuel supply valve can be arbitrarily set for a constant lift of the cam, and the amount of gaseous fuel supplied can be changed. This allows for adjustment.

Furthermore, the structure in which the fitting hole of the rocker arm and the large diameter portion of the swing shaft are fitted and integrated in a phase-adjustable manner in each of the above embodiments is not limited to the illustrated structure using the screws 17, 17, for example. It is also possible to adopt a configuration in which the mating hole and the large diameter portion are spline-fitted. Further, a rocker arm whose lever ratio can be changed can be interposed between a fuel cam and a tappet driven by the cam.

As described above, according to the present invention, in the fuel supply device for a gaseous fuel engine in which a fuel supply valve installed on a gaseous fuel supply path is opened and closed at a predetermined timing by a cam via a rocker arm, the rocker arm Since the lever ratio can be set arbitrarily, it is possible to freely adjust the lift amount or opening degree of the fuel supply valve with respect to the constant lift amount of the cam. According to the present invention, the air-fuel ratio in each combustion chamber can be kept constant even when the amount of intake air into the combustion chamber of each cylinder is different, and deterioration of drivability due to variations in combustion conditions can be prevented. For example, by appropriately selecting the opening timing of the fuel supply valve, dangers due to gaseous fuel discharge can be prevented.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional front view showing an embodiment of the fuel supply device of the present invention, FIG. 2 is a perspective view of the swing shaft in the embodiment, and FIG.
The figure is an enlarged front view of main parts showing the function of this embodiment, and Section 4.5.
FIG. 6 is a longitudinal sectional front view of a main part showing other embodiments. 5...Fuel supply path, 7...Fuel supply valve, 10. ll
'. 11"...Rocker arm, 12...l movement M, 13
...Bracket, 14...Large diameter section, 15...Small diameter section Applicant: Kubota Iron Works Co., Ltd. 11-71 Agent: Shuttle Tani (-, Nishi-1)

Claims (1)

[Claims] (1) In a configuration in which a fuel supply valve installed on a gaseous fuel supply path is opened and closed by a cam via a four-wheeled arm, the swing axis of the rocker arm is constituted by a large diameter portion and a small diameter portion that are eccentric to each other. 1. A fuel supply device for a gaseous fuel engine, characterized in that a diameter portion is fixed to a fitting hole formed in a P-locker arm so as to be able to adjust its phase, and a small diameter portion is rotatably supported on a bearing bracket.