JPS584186B2 - Gasoline injection internal combustion engine injection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an injection device for a gasoline-injected internal combustion engine.

Various types of gasoline injection devices have already been proposed, but no one with sufficient performance to replace a carburetor has yet appeared.

It is said that the fuel injection device for a gasoline-injected internal combustion engine may be similar to the fuel injection device for a diesel engine, but it cannot be said that they are exactly the same.

The reason is as follows. First, the fuel for gasoline-injected internal combustion engines (gasoline) has a lower viscosity than the fuel for diesel engines (light oil or heavy oil), so if you use a fuel injection system for diesel engines as is, the fuel will flow from the compression chamber side to the fuel tank side. It is inevitable that this will leak back.

Second, a normal gasoline-injected internal combustion engine with an automatic valve is
Whereas gasoline is injected into the intake tract, diesel engines inject fuel into the cylinder.

Therefore, while a gasoline-injected internal combustion engine requires an injection pressure of 10 to 20 atmospheres, a diesel engine requires an injection pressure of 2
There is a significant difference between 00 and 800 atmospheres.

Therefore, the fuel injection device of a diesel engine is dog-shaped in order to have strength, and the mass of the reciprocating parts is large.

On the other hand, the reciprocating portion has a limit to the number of times it can move per minute, and as it becomes larger and its mass increases, it is inevitable that the number of times it moves per minute will decrease.

This means that if the fuel injection system of a conventional diesel engine is converted to gasoline injection internal combustion, high-speed rotation will not be possible.

The present invention aims to ensure sealing performance and followability against high-speed rotation by using a lightweight hard nylon member to connect and disconnect the oil passage connecting the fuel tank and the pressure chamber.

An embodiment of the present invention will be described based on the drawings.

1 is the lower body, 2 is the crankshaft (not shown)
3 is a cam, 4 is a tappet slidably fitted to the lower body 1, and 5 is a roller pivotally supported on the tappet 4 by a pin 6.

The lower half γ is configured as described above. Reference numeral 8 designates an upper body, and a cylinder 9 provided on the upper body 8 is fitted with an annular plate 10 and an oil passage block 13 fitted with upper and lower oil seals 11 and 12. A rod guide 15 is fitted thereinto and further tightened with a nut 17 having several tightening recesses 16, . . . , 16.

18 is a rod that passes through the rod guide 15, oil seal 12, oil passage block 13, oil seal 11, and annular plate 10, and a coil spring 20 is compressed between the spring seat 19 provided at the lower end and the nut 1γ. There is.

21 is an automatic valve screwed into the upper body 8, 22 is a valve seat of the automatic valve 21, 23 is a needle valve, and 24 is a valve spring.

25 is a cap body placed on the upper end of the rod 18, 26 is a cap body 25
27 is a hard nylon plate fixed to the inner surface of the cap body 2.
5 and the valve seat 22, and 28 is a relief valve.

The upper half portion 29 is configured as described above. Thus, the upper half 29 is attached to the lower half 7 by bolts 30.

A certain amount of oil pressure is always applied to the fuel pipe 31.

When the cam 3 is inactive, the gasoline in the fuel pipe 31 flows through the oil passage 32 of the oil passage block 13 and into the rod 1.
8 oil hole 33, gap (about 1 mm) A between the upper end surface of rod 18 and nylon plate 26, through hole 34 of cap body 25
The gasoline is sent to the pressure chamber 35 through the gasoline, and the pressure chamber 35 is filled with gasoline.

When the cam 3 begins to rise, the upper end of the rod 18 first contacts the nylon plate 26 and closes the through hole 34.

As the cam 3 continues to rise, the cap body 25 is pushed up by the rod 18, and the oil pressure of gasoline in the pressure chamber 35 suddenly increases, opening the automatic valve 21 and pumping the gasoline into the combustion chamber (not shown) through the high pressure oil path 36. is injected into.

When the injection of gasoline ends and the automatic valve 31 closes, the rod 18 is lowered by the action of the cam 3 almost at the same time.

While the rod 18 is descending, the space between the upper end of the rod 18 and the nylon plate 26 opens slightly, gasoline is replenished into the pressure chamber 35, and the pressure chamber 35 returns to its initial state.

As described above, the injection device for a gasoline injection internal combustion engine according to the present invention includes a cap body 25 having a hard nylon plate 26 fitted and fixed to the upper end of the rod 18 which is reciprocated by the cam 3 interlocking with the crankshaft. body 25
A pressure chamber 35 is provided outside the pressure chamber 35, and an automatic valve 21 is connected to the pressure chamber 35. When the rod 18 is in the retracted position, the oil hole 33 of the rod 18 and the gap A1 between the rod 18 and the hard nylon plate 26 are connected to the cap body 25. The fuel pipe 31 and the pressure chamber 35 are communicated through the provided through hole 34, and at the beginning of the forward movement of the rod 18, the rod 18 is connected to the hard nylon plate 2.
6 to cut off the fuel pipe 31 and the pressure chamber 35,
It is constructed so that the pressure chamber 35 is compressed by the advancement of the rod 18.

The oil passage leading to the fuel tank (not shown) via the fuel pipe 31 and the pressure chamber 35 are connected and disconnected between the upper end of the rod 18 having the oil hole 33 and the hard nylon plate 26. Therefore, the sealing performance is better than that of diesel engines, which are made of metal, and there is no oil leakage even when using gasoline, which has a lower viscosity than diesel engine fuel.

In addition, since the mass of the cap body 25 and the hard nylon plate 26 is small, the impact load applied to the upper end of the rod 18 during reciprocating movement of the rod 18 is small, and the required strength of the cam 3 and the rod 18 is reduced, making the entire structure lightweight and compact. can be converted into

Furthermore, the cap body 25 and the hard nylon plate 26, which have small masses, have the advantage of well following the high-speed reciprocating motion of the rod 18.

In the case of diesel engines, the injection pressure is high, so hard nylon members lack strength and it is impossible to disconnect the oil passage, but gasoline-injected internal combustion engines have low injection pressure, so hard nylon members do not have enough strength to disconnect the oil passage. It is possible to connect and disconnect the oil passage with a nylon member, and the present invention skillfully utilizes this point to allow the gasoline-injected internal combustion engine to rotate at high speed.

[Brief explanation of the drawing]

The drawings show an embodiment of the injection device for a gasoline-injected internal combustion engine according to the present invention, and FIG. 1 is an overall longitudinal sectional front view, FIG. 2 is an enlarged view of the main part of FIG. 1 when the cam is in a non-operating state,
FIG. 3 is an enlarged view of the main part of the cam in an operating state, and FIG. 4 is a cross-sectional plan view taken along line B-1 in FIG. 2. 3...cam, 18...rod, 21.
... Automatic valve, 25 ... Cap body, 26 ...
...Hard nylon plate, 31...Fuel pipe, 33...Oil hole, 34...Through hole,
35... Pressure chamber.

Claims (1)

[Claims] 1. A cap body with a hard nylon plate fitted and fixed is placed on the upper end of the rod that is reciprocated by a cam interlocked with the crankshaft, a pressure chamber is provided on the outside of the cap body, and an automatic valve is connected to the pressure chamber, When the rod is in the retracted position, the fuel pipe and the pressure chamber are communicated through the rod's oil hole, the gap between the rod and the hard nylon plate, and the through hole in the cap body, and when the rod is in the early stage of forward movement, the rod is made of hard nylon. An injection device for a gasoline-injected internal combustion engine configured to contact a plate to shut off a fuel pipe and a pressure chamber, and compress the pressure chamber by advancing a rod.