JPS6245073Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a fuel supply system for a diesel engine using a unit injector.

Conventionally, in diesel engines that use a unit injector that integrates an injection pump and an injection nozzle as a fuel injection device, the center of the tip of the unit injector is slightly eccentric and inclined from the center of the cylinder bore. It is common to arrange the

In a multi-cylinder diesel engine having unit injectors arranged at an angle to the cylinder head for the number of cylinders, the fuel supply path for supplying fuel from the fuel feed pump to each unit injector is as follows: It is advisable to provide fuel to all unit injectors simultaneously and in series with one drill hole by providing a drill hole in the cylinder head parallel to the crankshaft.

Generally, in a multi-cylinder engine, each cylinder is designed to have the same position on its cross section, and a drilled hole parallel to the crankshaft passes through one unit injector hole. If it is arranged to supply fuel, it will penetrate other cylinders at the same position. However, if a fuel supply path is provided in the cylinder head as described above, the fuel inlet of the unit injector is opened into the fuel supply path, and the top and bottom of the opening are sealed with O-rings, etc., the fuel can be fed into the cylinder head. There is a problem in that after pressure is supplied, air accumulates in the upper part of the space partitioned by the upper and lower O-rings, and it is impossible to extract it.

Therefore, the present invention was devised to create a structure in which air can be vented from the space around the opening of the fuel inlet of the unit injector in the fuel supply path to the unit injector, which is provided at an angle in the cylinder head. It is.

That is, the present invention is a diesel engine in which a unit injector is installed in a mounting hole provided at an angle in the cylinder head, and the unit injector is parallel to the crankshaft of the diesel engine and penetrates through the inclined upper side of the mounting hole in the cylinder head. A fuel supply passage to the unit injector is provided through the unit injector, and O-rings are fitted to the upper and lower sides of the fuel supply passage at the fitting portion between the mounting hole and the unit injector.

Embodiments of the present invention will be described below with reference to the drawings.

First, in the diesel engine according to the embodiment of the present invention shown in FIGS. 1 and 2, the cylinder head 1
A unit injector 2 is installed in a mounting hole formed at an angle θ with respect to It is becoming more and more common.

Also, on the left and right of each unit injector 2,
An intake valve arm 6 and an exhaust valve arm 7 are provided, respectively, and these intake valve arms 6 and exhaust valve arms 7 are also lifted by intake and exhaust cams (not shown) provided on the camshaft 3, respectively. ing.

Next, a fuel supply passage 8 is provided in the cylinder head 1 by passing through a perforation hole parallel to the crankshaft of the diesel engine or the camshaft 3.

As shown in FIG. 2, this fuel supply path 8 is penetrated so as to be located on the inclined upper side of a mounting hole provided at an angle for mounting the unit injector 2.
The fuel inlet port of the unit injector 2 is opened, and the fuel supply path 8 is connected to the fitting part between this mounting hole and the unit injector 2.
Two O-rings 9a and 9b are fitted above and below to seal the fuel F.

Further, a solenoid valve 10 that can be opened only when the diesel engine is in operation is installed at the inlet portion 8a of the fuel supply path 8 provided in the cylinder head 1, and a solenoid valve 10 that can be opened only when the diesel engine is in operation is installed at the outlet portion 8b. Check valve 11 that adjusts the pressure of fuel F inside
is interposed.

In the fuel supply system of the present invention having the above configuration, one O-ring 9a, one O-ring 9b is provided at the top and bottom of the fuel inlet of the unit injector 2, and one O-ring 9b is provided at the top and bottom of the fuel inlet, respectively, to seal the fuel F. Since the fuel supply passage 8 penetrates through the relatively upper surface of the space partitioned by the O-rings 9a and 9b, the air accumulated in this space can be immediately and easily vented by the fuel F when the engine is started.

Therefore, if the present invention is applied to a diesel engine in which the unit injector is installed at an angle with respect to the cylinder head, the space around the opening of the unit injector's fuel inlet to the fuel supply path will be filled with water after the engine is stopped. For example, even if air accumulates, it can be easily released together with fuel to the check valve 11 located on the outlet 8b side of the fuel supply path 8 of the cylinder head when the engine is started, resulting in fluctuations in the supply fuel pressure in the fuel supply path. This has the effect of preventing this, and provides stable fuel injection.

The present invention can be effectively applied mainly to diesel engines having a unit injector.

[Brief explanation of the drawing]

Fig. 1 is a partial cross-sectional plan view of the main parts surrounding the unit injector provided in the cylinder head of a diesel engine according to an embodiment of the present invention, and Fig. 2 is a vertical cross-sectional view of the main parts of the unit injector shown in Fig. 1. It is. 1... Cylinder head, 2... Unit injector, 3... Camshaft, 8... Fuel supply path, 9
a, 9b...O-ring.

Claims (1)

[Scope of utility model registration request] In a diesel engine in which a unit injector is installed in a mounting hole provided at an angle in the cylinder head, the unit injector is parallel to the crankshaft of the diesel engine and passes through the inclined upper side of the mounting hole in the cylinder head. 1. A fuel supply system for a diesel engine, characterized in that a fuel supply passage is provided through the unit injector, and O-rings are fitted to the upper and lower sides of the fuel supply passage, respectively, at the fitting portion between the mounting hole and the unit injector.