JPS6118183Y2 - - 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 combustion 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 in 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 room 6.

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 combustion proceeds in both chambers, the maximum combustion temperature is suppressed compared to when the entire amount of injected fuel is supplied only to swirl chamber 1 and combusted, resulting in the generation of NOx, which is a harmful substance. It is known that the amount decreases.

However, on the other hand, due to the mounting position of the fuel injector 7, the sub-nozzle 5 must be formed to face the vortex in the vortex chamber 1, so that the injection through the main nozzle 4 during the compression stroke The problem is that the vortex tends to be offset by the jet from the sub-nozzle 5, and as a result, combustion in the vortex chamber 1 becomes sluggish, resulting in poor fuel efficiency, and furthermore, the amount of smoke tends to increase in the high-load conversion range. There is also.

The present invention was developed with attention to these problems, and the sub-nozzle is formed so as to open midway through the main nozzle, and a mask portion is provided at the opening of the sub-nozzle facing the main nozzle. The purpose of this invention is to solve the above-mentioned conventional problems by reducing the flow of air to the sub-nozzle during the compression stroke.

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

In the present invention, for example, as shown in the figure, the opening 4B of the main nozzle 4 on the main chamber 6 side is formed so as to be located near the center of the cylinder, and the auxiliary nozzle 5 is formed in the middle of the main nozzle 4.
The positions and shapes of each part are determined so that the fuel injection valve 7 opens and the center line l of the spray from the fuel injection valve 7 passes through the main nozzle opening 4B. Further, the sub-nozzle opening 5A facing the main nozzle 4 is provided with a mask portion 8 that covers the opening 5A from the main nozzle opening 4B side to the extent that it does not interfere with the spray center line 1. In this case, the main nozzle opening 4 is
It is preferable to set the positional relationship of each part so that the sub-nozzle (opening 5A) does not appear through B.

Based on this configuration, the main chamber 6 during the compression stroke
The flow of air from the sub-nozzle 5 to the vortex chamber 1 bypasses the mask portion 8 with respect to the sub-nozzle 5, resulting in a reduced flow rate and a turbulent flow, so that the air flows mainly through the main nozzle 4. In other words, the airflow into the vortex chamber 1 via the sub-nozzle 5 is weakened in both its flow velocity and direction, so that the strong pushing vortex generated in the vortex chamber 1 via the main nozzle 4 is forced from the sub-nozzle 5. It cannot be weakened by jets. Therefore, good combustion is achieved in the swirl chamber 1, and as a result, the amount of smoke is reduced. Furthermore, since the spray center line l of the fuel injector 7 is designed to reach the main chamber 6 without interfering with the mask part 8, etc., the fuel part with strong penetrating force near the center of the spray can be easily penetrated, as in the conventional case. It can be supplied to the main room 6.

As described above, according to the present invention, it is possible to improve combustion in the vortex chamber, improve fuel efficiency, and reduce smoke, which tends to increase particularly in high-load operating ranges.

[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, 4B... Main chamber side opening of main nozzle, 5...
Sub-nozzle, 5A... Opening of the sub-nozzle facing the main nozzle, 6... Main chamber, 7... Fuel injection valve, 8... Mask portion of the sub-nozzle, l... Spray center line of the fuel injection valve.

Claims (1)

[Scope of utility model registration request] In a diesel engine, 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 through a sub-nozzle opening in the injection direction of the fuel injection valve in addition to the main nozzle. , the main nozzle and the auxiliary nozzle are formed such that the auxiliary nozzle opens in the middle of the main nozzle, and the center line of the fuel spray of the fuel injection valve passes through the main chamber side opening of the main nozzle; A combustion chamber for a swirl chamber type diesel engine, characterized in that a mask portion is provided to cover an opening of a sub-nozzle facing the main nozzle from the main chamber-side opening of the main nozzle to an extent that it does not interfere with the spray center line.