JPS6118184Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a swirl chamber type diesel engine, and more particularly to an improvement of a fuel chamber that improves combustion by providing a plurality of nozzles that communicate the swirl chamber and the main chamber.

The swirl chamber type is known as a type of combustion chamber suitable for high-speed diesel engines, but in order to further improve its combustion properties, a combustion chamber with multiple nozzles communicating between the swirl chamber and the main chamber has been proposed. (For example, Japanese Patent Application Laid-open No. 51-105509).

To explain this with reference to FIG. 1, the vortex chamber 1 is formed into a substantially spherical shape between an engine cylinder head 2 and a mouthpiece 3 fitted from the bottom surface thereof, and has a main nozzle 4 and a relatively small diameter sub-nozzle 5. It communicates with the main room 6 via.

The main injection port 4 has an opening 4A on the swirl chamber 1 side opening in the tangential direction of the spherical swirl chamber 1, and an opening 4B on the main chamber 6 side opening slightly toward the center of the cylinder. The gas jet from 1 is ejected toward the center of the main chamber 6. On the other hand, the small-diameter sub-nozzle 5 opens along the injection direction of the fuel injection valve 7 facing the swirl chamber 1, so that a part of the injected fuel flows out into the main chamber 6 during the ignition delay. It is set as.

According to such a combustion chamber, not only the vortex chamber 1 but also the main chamber 6 in which gas flows gently through the sub-nozzle 5
Since fuel is supplied to both chambers and the fuel advances in both directions, the maximum combustion temperature is suppressed compared to the case where the entire amount of injected fuel is supplied only to swirl chamber 1 and combusted, and as a result, NOx, which is a harmful substance, is generated. It is known that the amount decreases.

However, on the other hand, due to the mounting position of the fuel injection valve 7 and the need to reliably supply a predetermined amount of fuel to the main chamber 6, the sub-nozzle 5 is oriented so as to face the swirling flow in the swirling chamber 1. Moreover, since it has to be formed with a somewhat large diameter, there is a tendency for the forced vortex flow through the main nozzle 4 during the compression stroke to be attenuated by the jet flow from the auxiliary nozzle 5, and as a result, the combustion in the vortex chamber 1 There are also problems in that the engine speed becomes sluggish, resulting in poor fuel efficiency, and the amount of smoke tends to increase in high load ranges.

This invention was made with an eye on these problems, and its purpose is to solve the above-mentioned problems of the conventional technology by providing a fuel reservoir section in the middle of the auxiliary nozzle that is connected to the main nozzle, and by diverting the injected fuel flowing into the auxiliary nozzle to the auxiliary nozzle and the main nozzle and supplying it to the main chamber.

The present invention will be explained below based on the embodiment shown in FIG. Note that parts corresponding to those in FIG. 1 are designated by the same reference numerals.

In the present invention, as shown in the figure, the opening 5A on the main chamber 6 side of the sub-nozzle 5 formed to face the fuel injection valve 7 is made smaller in diameter than the opening 5B on the swirl chamber 1 side, and is stepped in the middle. A fuel reservoir 8 is formed,
Furthermore, this fuel reservoir 8 and the middle of the main nozzle 4 are communicated through a small through hole 9.

Based on the above configuration, the fuel from the fuel injection valve 7 flows directly into the main chamber 6 through the main chamber side opening 5A of the sub-nozzle 5, but the fuel from the center of the spray flows directly into the main chamber 6 through the main chamber side opening 5A of the sub-nozzle 5, but the fuel from the center of the spray The fuel distributed slightly outward flows from the peripheral area of the swirl chamber side opening 5B, collides with the fuel reservoir 8, and flows from the main nozzle 4 to the main chamber 6 via the through hole 9. The fuel distributed further outside the fuel spray collides around the opening 5B and burns in the swirl chamber 1 together with the ignited injected fuel. Incidentally, in this embodiment, the fuel temporarily retained in the fuel reservoir 8 naturally flows to the main nozzle 4 because the through hole 9 is inclined toward the main nozzle 4;
When combustion starts, the combustion gas is actively sucked out as it passes through the main nozzle 4 and ejects into the main chamber 6, so that it is quickly supplied to the main chamber 6 together with the ejected gas.

In this way, a sufficient amount of fuel flowing into the vortex chamber side opening 5B having a large opening area is supplied to the main chamber 6 which has a sufficient amount of air through the main chamber side opening 5A and the through hole 9. Based on the intensive combustion in the swirl chamber 1, as a result of the combustion occurring in both the swirl chamber 1 and the swirl chamber 1.
This prevents the generation of NOx, but in addition to this, in the present invention, the main chamber side opening 5A of the sub-nozzle 5 is increased by the amount of fuel supplied to the main chamber 6 through the through hole 9.
Since the diameter can be made small, it is possible to reduce the harmful forced flow that flows into the vortex chamber 1 through this sub-nozzle 5 during the compression stroke, that is, to perform good combustion without weakening the vortex in the vortex chamber 1. Can be done.

As described above, according to the present invention, it is possible to suppress the generation of NOx while avoiding the deterioration of combustion that has been a problem with conventional swirl chambers with sub-nozzles, thereby improving fuel efficiency and reducing smoke. be.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a conventional example, and FIG. 2 is a longitudinal sectional view of an embodiment of the present invention. 1... Vortex chamber, 2... Cylinder head, 4...
Main nozzle, 5... Sub-nozzle, 5A... Opening of the sub-nozzle on the main chamber side, 5B... Opening of the sub-nozzle on the swirl chamber side, 6...
...Main chamber, 7...Fuel injection valve, 8...Fuel reservoir,
9...Through hole.

Claims (1)

[Scope of utility model registration request] A diesel engine in which a swirl chamber with a fuel injection valve facing the engine cylinder head is provided, and the swirl chamber and the main chamber are communicated via a sub-injection port that opens in the injection direction of the fuel injection valve in addition to the main injection port. The main chamber side opening of the sub-nozzle is made smaller in diameter than the swirl chamber side opening, and a stepped fuel reservoir is formed in the middle, and the fuel reservoir and the main nozzle are connected through a through hole. A combustion chamber of a swirl chamber type diesel engine characterized by being in communication with each other.