JPS6040852Y2 - Diesel engine fuel injection valve - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a fuel injection valve for a diesel engine.

Large, highly supercharged diesel engines use cooling-type fuel valves, but in medium-sized or small-sized engines, cooling of the fuel injection valves is especially important because the cooling effect of the cylinder head is large. Not yet.

Therefore, in conventional small and medium-sized diesel engines, the fuel injection valve is attached to the cylinder head without taking any measures for cooling the cylinder head, as illustrated in FIGS. 1 and 2.

That is, in FIG. 1, the fuel injection valve 2 is attached to the cylinder head 1 through the holder 3 within the opening la.

Reference numeral 4 denotes a backing made of a heat insulating material made of Teflon or the like and interposed between the holder and the cylinder head 1.

Furthermore, FIG. 2 shows an example in which the fuel injection valve 2 is installed in the sleeve 5 attached to the cylinder head 1 in the same way as in FIG. 1.
In all of these conventional examples, a passive cooling measure is taken by interposing a backing 4 made of a heat insulating material on the fuel injection valve 2, and no attempt is made to actively cool the fuel injection valve. do not have.

Therefore, with conventional devices, cooling of the fuel injector is insufficient when the engine is under high load, and combustion performance may deteriorate due to clogging of the nozzle or carbon flour caused by dripping after one injection. No countermeasures have been taken against this, and there are problems with the durability and reliability of fuel injection valves.

The present invention is an attempt to eliminate such drawbacks of conventional devices. the cavity is opened at the tip of the fuel injection valve (near the tip), and the cavity is connected to the air supply system to introduce outside air into the cavity during the intake stroke of the engine; The feature is that the fuel injection valve is cooled and the air is flowed out from the opening at the tip of the fuel injection valve, thereby blowing away drippings and carbon flour that adhere to the nozzle of the fuel injection valve. It is something.

Next, an embodiment of the present invention will be described based on FIGS. 3 to 5.

First, in FIG. 3, the fuel injection valve 2 of the cylinder head 1
A fuel injection valve 2 is attached by a holder 3 to the opening 1a for attaching the fuel injection valve.

At this time, the fuel injector 2 is attached to the cylinder head 1 so that a small cavity 11 is formed between the outer peripheral surface of the tip 2a of the fuel injector 2 and the wall surface of the opening 1a. do.

A passage 7 communicating with an intake manifold (not shown) of the engine is provided in the cavity 11, and a check valve 6 is provided in the middle of the passage 7.

Reference numeral 10 denotes a heat-resistant insert provided at the inner end of the opening 1a of the cylinder head 1, and a small hole is bored in the center of the insert from which the nozzle 12 at the tip of the fuel injection valve projects.

The inner peripheral surface of the insert 10 is provided with a guide 9 for causing the air introduced into the cavity 11 to flow out along the nozzle 12.
is formed.

In operation, during the intake stroke, outside air is introduced into the cavity 11 through the intake manifold, the check valve 6, and the passage 7, and the fuel injection valve is cooled by this air, thereby preventing the fuel injection valve from overheating.

Furthermore, this air flows along the nozzle 12 by the guide 9 and is ejected into the combustion chamber;
It has the effect of blowing away fuel, carbon flour, etc. that have adhered to the area around 2.

FIG. 4 shows an example in which no insert is used, in which case the guide 9 is formed directly on the base material of the cylinder head.

FIG. 5 shows an example of using the sleeve 5, and the guide 9
is formed on the sleeve 5.

The example shown in FIGS. 4 and 5 differs from the example shown in FIG. 3 only in this respect, and is completely the same in other respects.

Also, the arrows in the figure indicate the air flow during the intake stroke,
During the compression stroke, the passage 7 is closed by the check valve 6, so
It is clear that there is no risk of the gas in the combustion chamber flowing out through the cavity 11 during the compression stroke and expansion stroke.

As described above, according to the present invention, the fuel injection valve of a diesel engine is cooled, so the durability of the fuel injection valve can be further improved, and fuel and carbon attached to the nozzle can be easily removed. It can be used to stabilize combustion, and is especially effective when applied to small and medium-sized engines that do not use cooled fuel injection valves.

In addition, in engines equipped with an air tank, cooling air is supplied to the cavity by supplying pressurized air in the tank by operating an appropriate valve mechanism near the end of the combustion stroke. , it is possible to achieve a further cooling effect and a cleaning effect of the nozzle part.

[Brief explanation of drawings]

1 and 2 are side sectional views of a conventional fuel injection valve installation section, and FIGS. 3 to 5 are side sectional views of a fuel injection valve installation section according to the present invention. 1 cylinder head, 2: fuel injection valve, 3: holder, 4
: Packing, 5 sleeves, 6: Check valve, 7: Passage,
9 Ni guide, 10: insert, 11: cavity, 12:
Spout.

Claims (1)

[Scope of utility model registration request] Install the fuel injector into the opening of the cylinder head so that a small cavity is formed between the area around the tip of the fuel injector and the wall of the opening for mounting the fuel injector. A fuel injection valve for a diesel engine, in which the cavity is opened in the vicinity of the fuel injection valve, and the cavity is connected to the intake system of the engine via a check valve in the middle.