JPS6012932Y2 - Fuel injection pump for internal combustion engines - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a fuel injection pump for internal combustion engines, and more specifically, the present invention relates to a new fuel injection pump (
This invention relates to an improvement of the plunger structure in Japanese Utility Model Application No. 52-280317).

As shown in Figure 1, Japanese Utility Model Application Publication No. 52-80317,
The plunger 7 is reciprocated within the barrel 8 to forcefully feed the fuel, and the cylindrical annular valve 9 fitted into the lower body 7b of the plunger 7 is rotated and moved up and down. A circular fuel oil port 1 provided in the plunger 7
A fuel injection pump for an internal combustion engine is shown in which the amount of plunger stroke that closes the plunger 7 and the timing of opening and closing the plunger 17 are changed, thereby adjusting the amount of fuel injection and the injection timing.

However, if the clearer 17 is made circular as in this known example, the clearer 17 will become smaller when downsizing the pump, and the annular valve 9 will move downward during advance, that is, at high speed rotation, and the fuel will flow. As the flow area A1 decreases, the plunger speed increases, resulting in poor fuel filling efficiency and poor injected fuel, resulting in afterburning.

In an attempt to improve this problem, for example, by advancing the injection timing, fuel control becomes difficult due to the small size of the fuel 17, resulting in abnormalities such as incomplete combustion.

Furthermore, since the increase/decrease in the fuel flow area is small considering the vertical position of the annular valve 9, the adjustment range of the fuel injection timing cannot be adjusted very much. In other words, it is necessary to increase the plunger diameter or the lift amount of the annular valve 9, which causes the problem that the fuel injection pump itself becomes larger.

The present invention was developed in order to improve the above-mentioned problems, and by making the cutout provided in the lower body of the plunger into a trapezoidal groove-like notch that is vertically elongated and expands downward, it is possible to improve the fuel consumption. It is an object of the present invention to provide a fuel injection pump for an internal combustion engine, which reduces suction resistance and allows a wide adjustment range of fuel injection timing without increasing the size of the fuel injection pump itself.

Hereinafter, the fuel injection pump of the present invention will be explained based on the embodiment shown in FIGS. 2 to 5. In FIG. 3 is a camshaft, 4 is a cam plate, 5 is a cam roller,
6 is an oil chamber formed above the plunger 7; 8 is a barrel;
9 is a cylindrical nine-ring valve having lead surfaces 2021 on the upper and lower end surfaces, 10 is a discharge valve seat, and 11 is a discharge valve.

The head 7a of the plunger 7 is inserted into the barrel 8, and the plunger 7 functions to force-feed the fuel oil sucked into the oil chamber 6 by its reciprocating motion.
A disk-shaped spring receiver 12 is fitted into the small diameter portion 15 between the camshaft 1 and the camshaft 3.b is fitted with a disk-shaped spring receiver 12 that receives a spring 1314 that acts to urge the plunger 7 toward the camshaft 3.

The plunger 7 has a barrel 8 by engaging a detent pin 32 in a vertical groove 30 formed on the side surface of the head 7a.
It is considered non-rotating.

Furthermore, an oil passage 16 is formed in the axial center of the plunger 7, and the oil passage 16 is connected to the oil chamber 6 and the plunger through a horizontal communication hole 17 (FIG. 3) provided at its lower end. Clearance 1 serving as a fuel intake/exhaust port formed on the side surface of the lower body portion 7b
It communicates with 8.

As shown in FIGS. 2 and 5, this clearing hole 18 is a vertically elongated substantially trapezoidal groove formed such that both side edges 18a, 18a widen downward, and its upper edge 18c has an annular shape as described below. The slope is in the same direction as the slope (angle θ1) of the sloped lead portion 20b of the upper lead surface 20 of the valve 9, and at almost the same angle (angle θ2
θ1), that is, approximately parallel to the inclined lead portion 20b, the lower edge 18b is formed horizontally, and the bottom surface 18b is formed horizontally.
8d is formed to be inclined at an angle θ4 so that the lower part thereof becomes deeper (FIG. 3), and one end of the communication hole 17 for communicating the oil passage 16 and the oil passage 18 is opened in the bottom part 18d. I'm being forced to do it.

In the illustrated embodiment, the clear white 18 formed in this way is further divided into lines 18 of the clear white 18 as shown in FIGS. 3 and 5.
a, 18a, 18b, 18c are tilted so as to expand outward (angles θ6, θ6, θ5, θ5, θ, respectively)
3) to further reduce the fuel suction resistance.

On the other hand, an annular valve 9 is slidably and rotatably fitted into the lower body portion 7b of the plunger 7 and operates to open and close the cleaner 18 as the plunger 7 reciprocates.

The annular valve 9 is a cylindrical body having teeth 19 formed around it that mesh with the regulating rack 31, and an upper lead surface 20 and a lower lead surface 21 of an appropriately shaped shape formed on both upper and lower end surfaces.
The upper lead surface 20 further includes an upper side 20a and an inclined lead portion 20.
It is made up of three parts: b and lower side 20c, and the timing of opening and closing the cleanser 18 is changed within the range of the inclined lead part 20b, thereby changing the fuel injection amount.

That is, in the ring valve 9, a part of the clear white 18 is located on the upper lead surface 2.
0 or below the lower lead surface 21, the clear white 18 is open, and when the entire clear white 18 is between the upper lead surface 20 and the lower lead surface 21, the clear white 18 is opened. It acts to block the fuel and force the fuel to flow.

Further, the annular valve 9 is rotated by a regulating rack 31 to adjust the amount of fuel injection by changing the stroke amount of the plunger that closes off the aforesaid cleanser 18. The valve bearing shaft 2 is rotated via the adjustment plate 27 by advancing and retracting the fuel injection timing adjustment rack 28 (provided on the opposite side and parallel to the speed control rack 21).
The eccentric pin 26 provided at the tip of the fuel injection valve 3 is inserted, and as the eccentric pin 26 is displaced in the vertical direction, the time to close the clean white 18, that is, the prelift 11 is changed, and the fuel injection timing is adjusted. .

Next, the operation of the fuel injection pump of the illustrated embodiment will be explained. In this fuel injection pump 1, the plunger 7 reciprocates within the barrel 8 due to the rotation of the camshaft 3, and the plunger 7 moves from the bottom 18 provided in the lower body portion 7b. The fuel sucked into the oil chamber 6 is pressurized and fed under pressure from a discharge valve 11 to a fuel injection valve (not shown).

When the engine is in a high-speed rotation range, the annular valve 9 is moved downward by the fuel injection timing adjustment rack 28 in order to advance the fuel injection magnetism (the position shown by the solid line in FIG. 2), and the pre-lift 11 of the plunger 7 is extremely However, in the illustrated embodiment, the clearing hole 18 is a substantially trapezoidal concave groove, so even though the prelift 11 is small, the fuel flow area A2 is large and the fuel suction resistance is small, so that the fuel flow into the oil chamber 6 is small. Fuel filling efficiency becomes better.

Furthermore, since the clearing hole 18 is formed into a substantially trapezoidal groove, the fuel flow area A is reduced even when the annular valve 9 is slightly vertically displaced.
2 changes significantly, the adjustment range of the fuel injection timing can be widened, and the lift of the annular valve 9 can be kept small, making it possible to downsize the device itself.

The upper edge 18c of the clear white 18 has an appropriate width and is substantially parallel to the upper lead surface 20 and the inclined reed surface 20b of the annular valve 9.
When the clear white 18 is opened above 0, the upper edge 18c of the clear white 18 is opened from the inclined lead part 20b of the upper lead surface 30.
Since a large-area fuel oil escape path is formed at the same time as the fuel leaks out, the fuel injection path becomes sharp, eliminating the afterburning phenomenon and improving combustion performance.

Next, to explain the effects of the present invention, as is clear from the above explanation, the fuel injection pump of the present invention has a substantially trapezoidal vertical groove that expands downward in the fuel suction/discharge provided on the plunger. This reduces fuel suction resistance and improves fuel filling efficiency, resulting in better fuel injection characteristics.
Furthermore, the control range of the fuel injection timing can be widened without increasing the plunger diameter or the lift of the annular valve, making it possible to finely adjust the fuel injection timing and making it possible to downsize the fuel injection pump itself. This is effective.

In addition, if the upper edge of the clear white 18 is formed almost parallel to the inclined reed portion of the upper reed surface of the annular valve as in the illustrated embodiment, the fuel injection path becomes sharp, improving the combustion performance of the engine and also improving the exhaust composition. There is an effect that

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the main part structure of a conventional fuel injection pump for an internal combustion engine, Fig. 2 is an explanatory diagram of the structure of a fuel injection pump for an internal combustion engine according to an embodiment of the present invention, and Fig. 3 is an explanatory diagram of the structure of the fuel injection pump for an internal combustion engine according to an embodiment of the present invention. 4 is a sectional view taken along the line IV--IV in FIG. 3, and FIG. 7... Plunger, 7a... Plunger head, 7b... Plunger lower body, 8... Barrel, 9... Annular valve, 16... ... Oil passage, 18 ... Clear white, 20 ... Upper lead surface, 21 ... Lower lead surface.

Claims (1)

[Scope of utility model registration request] The head 7a of the plunger 7, which has an oil passage 16 communicating from the head 7a to the lower body 7b, is fitted into the barrel 8, while the lower body 7b has an upper or lower part of an appropriately shaped upper and lower end surface. Said plunger 7 has a lead surface 20.21.
An annular valve 9 that opens and closes the cleanser 18 communicating with the oil passage 16 as the plunger reciprocates is rotatably and slidably inserted, and the annular valve 9 is rotated around the axis of the plunger 7. The annular valve 9 adjusts the amount of fuel injection by changing the stroke of the plunger that closes the clearer 18, while the annular valve 9 is moved up and down in the direction of the axis of the plunger 7 so that the annular valve also closes the clearer. In this fuel injection pump, the fuel injection timing is adjusted by changing the timing of opening and closing 18, and the plunger 7 has a substantially trapezoidal vertical groove that expands downward. A fuel injection pump for internal combustion engines featuring: