JPS5833214Y2 - Chiyokusetshuunshiyashikiday-Zelkikan - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a direct injection diesel engine.

More specifically, the present invention relates to a direct injection diesel engine that can uniformly control the formation of a mixture of fuel and air in a combustion chamber and the development of a combustion flame, thereby contributing to increased output and reduced smoke.

The deep-dish combustion chamber of a direct injection diesel engine has a small combustion chamber diameter compared to the piston diameter, so at the end of the piston compression stroke there is a strong forced flow of air between the combustion chamber and the top gap, i.e. A squish occurs, and after top dead center, a reverse squish occurs in the opposite direction.

Furthermore, if the intake air is swirled, the speed of the piston at top dead center will be increased several times.

This initial swirl is called cylinder swirl, and the latter accelerated swirl is called bowl swirl.

These air flows such as squish, reverse squish, and swirl have an important influence on the formation and combustion of air-fuel mixture, and ideal combustion can be achieved by appropriately controlling and balancing these.

However, combustion using conventional deep-dish combustion chambers has the disadvantage that the air flow is not ideally controlled, resulting in uneven fuel distribution and insufficient combustion performance.

In other words, in a conventional direct injection diesel engine with a deep-dish combustion chamber, the fuel distribution within the combustion chamber is relatively uniform, but the fuel distribution in the top gap is not uniform and may be incomplete. This causes smoke generation due to combustion and a decrease in output.

The role of the swirl in combustion is to stir the air-fuel mixture from the fuel injected from the injection nozzle and the air, and to distribute it uniformly in the circumferential direction within the combustion chamber.

The role of reverse squish in combustion is to forcefully send the burned and unburned gas mixture in the combustion chamber to the top gap, where it comes into contact with fresh air and is combusted. .

In other words, the fuel within the combustion chamber is distributed to the top gap.

However, in a deep-dish combustion chamber, a part of the spray from the injection nozzle adheres to the circumferential wall of the combustion chamber in the form of a film, and is evaporated and burned, but this injection is uniform in the circumferential direction of the combustion chamber wall. Since the fuel cannot adhere to the top gap, the distribution of the fuel carried out to the top gap by reverse squish will necessarily not be uniform.

If the large combustion chamber becomes eccentric from the center of the injection nozzle, the distance of the spray from each injection nozzle to the combustion chamber wall casing will vary slightly, resulting in a change in the amount of fuel deposited. The distribution of the fuel carried out by the reverse squish will also not be uniform.

In this way, in the case of a conventional deep-dish combustion chamber, even though the fuel distribution within the combustion chamber can be made uniform because the bowl swirl inside the chamber is accelerated, it is difficult to make the fuel distribution uniform in the circumferential direction of the top gap. cannot be achieved because the cylinder swirl is not accelerated.

Therefore, the purpose of the present invention is to eliminate the drawbacks of the conventional device as described above, and to make it possible to equalize the fuel distribution in both the combustion chamber and the top gap in a diesel engine with a deep-dish combustion chamber. It is an object of the present invention to provide a direct injection diesel engine which can reduce smoke and improve output by making the fuel distribution uniform especially in the top gap.

To achieve the above object, the present invention provides a direct injection type diesel engine in which a deep-dish combustion chamber 3 is provided at the top of a piston 2, and a fuel injection nozzle 5 having a plurality of injection ports faces the combustion chamber 3. A squish control plate 4 having a circular shape in plan view of the combustion chamber 3 and a polygonal opening having the same number of corners as the number of injection ports of the fuel injection nozzle 5 at the top of the combustion chamber 3.
The length by which the edge of the opening of the squish control plate 4 protrudes inward into the combustion chamber 3 is shortened in the portion corresponding to the injection direction of the nozzle, and the bowl swirl is formed from the portion corresponding to the injection direction. The feature is that the part corresponding to the downstream side is made longer.

The present invention will be specifically explained below using embodiments shown in the drawings.

FIG. 1 is a longitudinal sectional view of a direct injection diesel engine showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II in FIG.

Moreover, FIG. 3 is a cross-sectional view showing the fuel concentration distribution of the air-fuel mixture in a conventional diesel engine.

In FIGS. 1 and 2, 1 is a cylinder, and a piston 2 is fitted into this cylinder 1 and reciprocates up and down.

A deep dish-shaped combustion chamber 3 is provided at the upper end of the piston 2.
Furthermore, at the upper part of this combustion chamber 3, a squish control plate 4 whose brim extends at 1 inside the combustion chamber 3 so as to partially cover the upper part of the combustion chamber 3.
is fixed.

Reference numeral 5 denotes an injection nozzle mounted on the upper part of the cylinder, and this injection nozzle 5 has a fuel injection nozzle at 4@, and injects fuel in all directions within the combustion chamber 3.

The injection nozzle 5 is provided eccentrically by a distance X with respect to the combustion chamber 3.

The squish control plate 4 is connected to the injection nozzle 5 as shown in FIG.
The combustion chamber has a rectangular opening corresponding to the nozzle nozzle, and the distance from the side wall of the combustion chamber and the dimension l of each side and each corner are set to be different from each other.

6 is the top gap.

When the piston 2, which has a deep dish-shaped combustion chamber 3 at the top, completes its compression stroke and enters its downward stroke from top dead center, a reverse squish occurs as shown by arrow A in Figure 1, and then a reverse squish occurs as shown by arrow B in Figure 2. The cylinder swirl shown by is accelerated, and a bowl swirl shown by arrow C is formed.

In this case, in the case of a conventional deep-dish combustion chamber in which the squish control plate 4 is not provided, the fuel sprayed from the four injection nozzles 50 is slightly moved in the circumferential direction by the bowl swirl C in the combustion chamber 3. However, it is ejected radially toward the top gap 6 by the reverse squish A.

Therefore, in the top gap 6, as shown in Fig. 3, there is a portion D of 4 air-fuel mixtures with a high concentration and a portion E of 4 air holes with a low concentration, and in any case, the fuel is non-uniform. A distribution will occur.

In the present invention, as shown in FIGS. 1 and 2, a squish control plate 4 is provided at the upper part of the combustion chamber 3, and this squish control plate 4 has a portion corresponding to the E portion where the fuel distribution becomes lean. The protruding length l of the protrusion is made small, and the protruding length of the protruding part of the protrusion corresponding to the D part where the fuel distribution becomes rich is made large.

That is, the length by which the edge of the polygonal opening of the squish control plate 4 protrudes inward into the combustion chamber 3 is shortened at the portion corresponding to the injection direction of the jet nozzle, and from the portion corresponding to the injection direction. The part corresponding to the downstream side of the bowl swirl is made longer.

With this configuration, fuel can be easily injected into the top gap 6 by reverse squish from the main part with a small protrusion length, and from the L part with a large protrusion length, it is easy to inject fuel into the top gap 6. Injection of fuel into the top gap 6 due to squish is suppressed.

Therefore, the fuel distribution in the top gap 6 becomes uniform throughout.

In the above embodiment, a quadrilateral squish control plate was described, but a triangular, triangular, or
It can be set to any shape such as pentagonal cedar or hexagonal.

As described above, the present invention applies to a direct injection diesel engine in which a deep-dish combustion chamber 3 is provided at the top of a piston 2, and a fuel injection nozzle 5 having injection ports in multiple directions is disposed in the combustion chamber 3. The shape of the combustion chamber 3 in plan view is made circular, and
A squish control plate 4 having a polygonal opening with the same number of angles as the number of nozzles of the fuel injection nozzle 5 is provided at the top of the combustion chamber 3, and the edge of the opening of the squish control plate 4 is located inside the combustion chamber 3. The projecting length is made shorter in the part corresponding to the injection direction of the nozzle hole, and longer in the part corresponding to the downstream side of the bowl swirl from the part corresponding to the injection direction, so that the top gap due to reverse squish is reduced. The fuel distribution in the combustion chamber is controlled to be uniform, and ideal air utilization is achieved to ensure complete combustion.

Therefore, smoke due to incomplete combustion is reduced, making it possible to improve output.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a direct injection diesel engine showing an embodiment of the present invention, and FIG. 2 is a sectional view taken along line II in FIG. FIG. 3 is a cross-sectional view showing the fuel concentration distribution of the air-fuel mixture in a conventional diesel engine. 1...Cylinder, 2...Piston, 3
... Combustion chamber, 4 ... Squish control plate, 5 ... Injection nozzle, 6 ... Top [part,
A: Reverse squish, B: Cylinder swirl, C: Bowl swirl.

Claims (1)

[Scope of utility model registration request] A deep dish-shaped combustion chamber 3 is provided at the top of the piston 2.
In a direct injection diesel engine that is equipped with a fuel injection nozzle 5 having multiple injection ports, the combustion chamber 3 has a circular shape in plan view, and the fuel injection nozzle 5 has a injection port at the top of the combustion chamber 3. A squish control plate 4 having a polygonal opening having the same number of angles as the squish control plate 4 is provided.
The length by which the edge of the opening protrudes into the inside of the combustion chamber 3 is,
A direct injection diesel engine in which a portion of the injection port corresponding to the injection direction is shortened, and a portion corresponding to the downstream side of the bowl swirl from the portion corresponding to the injection direction is lengthened.