JPS6030417Y2 - Diesel engine swirl chamber structure - Google Patents

Description

[Detailed description of the invention] This invention relates to a swirl chamber structure for a diesel engine.

Generally, the swirl chamber of a diesel engine is created by inserting the mouthpiece from below into an enlarged recess formed at the bottom of the cylinder head, and forming a roughly spherical swirl chamber with the recess of the cylinder head and the recess of the mouthpiece. The fuel is forced into the vortex chamber through the nozzle hole to create a vortex, which mixes with the fuel from the injection nozzle to improve combustion conditions.

However, in the conventional swirl chamber structure, fuel tends to concentrate on the outer periphery of the spherical swirl chamber due to the swirl, and the air utilization rate in the center is poor, resulting in poor fuel mixing and half misfires when the engine is cold. This caused the problem of poor starting performance.

Therefore, in order to improve the startability of the engine when it is cold, a turbulence plate is inserted into the vortex chamber, as disclosed in, for example, Japanese Utility Model Publication No. 51-53366.

That is, if a turbulent flow plate is provided in the vortex chamber, the turbulent flow is disturbed by the turbulent flow plate, and the fuel and air are mixed well, improving the combustion state and improving the startability.

However, when the engine warms up and the temperatures of the walls of the combustion chamber and swirl chamber become high, the turbulence plate has the problem of reducing output and fuel efficiency.

This idea was made in order to solve the problems of the conventional ones.A turbulence plate is provided between the mouthpiece and the cylinder so that it can protrude into the vortex chamber, and this turbulence plate is used to control the temperature of the combustion chamber. Provides a swirl chamber structure for a diesel engine that improves startability when the engine is cold and prevents a decrease in output and fuel efficiency when the engine is warmed up by providing a turbulence plate operating means that projects into the swirl chamber only when the engine temperature is low. It is intended to.

An embodiment of this invention will be described below with reference to the drawings.

1 and 2 show a swirl chamber structure of a diesel engine according to an embodiment of this invention. In the figures, 1 is the cylinder head of the diesel engine, and the lower part of the cylinder head 1 has a substantially hemispherical recess 2. Enlarged recess 3 following
is formed.

Then, a cap 4 is inserted into the enlarged four part 3 from below,
A substantially spherical swirl chamber 6 is formed by the recess 2 of the cylinder head 1 and the recess 5 of the mouthpiece 4.

The mouthpiece 4 is formed with a nozzle hole 10 that communicates the vortex chamber 6 with the main combustion chamber 9 of the engine surrounded by the piston 7, cylinder 8, and cylinder head 1. The cylinder head 1 has a swirl chamber 6
An injection nozzle 11 for injecting fuel is provided.

A rectangular turbulence plate 12 is inserted between the upper part of the mouthpiece 4 and the inner wall surface of the enlarged recess 3 of the cylinder head 1. and has an opening 12a having the same shape as the opening 4a of the mouthpiece 4, and is moved in the left-right direction in the drawing depending on the temperature of the walls of the combustion chamber 9 and the swirl chamber 6 by means of a bimetal 13 and a leaf spring 14 inserted and arranged on both sides of the opening 12a, It projects into the swirl chamber 6.

Next, the operation will be explained.

When the engine is cold, that is, when the wall temperature of the swirl chamber 6 is low, the bimetal 13 is in the state shown in FIG. Projects into the chamber 6.

Then, the air in the combustion chamber 9 of the cylinder 8 is pushed into the vortex chamber 6 from the nozzle hole 10 as shown by the arrow A in the figure due to the rise of the piston 7, creating a vortex, and the air hits the protrusion 12b of the turbulence plate 12 and This generates turbulent flow and mixes well with the fuel injected from the injection nozzle 11, resulting in good combustion conditions.

On the other hand, when the wall temperature of the vortex chamber 6 increases, for example to about 200 degrees Celsius, as when the engine is warmed up, the bimetal 13 deforms as shown in FIG. Then, the opening 4a of the base 4 and the opening 12a of the turbulence plate 12 come to a position where they exactly coincide.

Therefore, when the engine is warmed up, the turbulent flow plate 12 does not disturb the vortex flow and reduce the output and fuel efficiency.

Note that this invention is not limited to the above embodiments,
For example, the turbulence plate 12 is connected to the injection nozzle 11 as in the above embodiment.
It is desirable that the protrusion be in a position where it is directly hit by the fuel from the fuel, but this is not necessarily the case.

Furthermore, the turbulence plate itself may have a completely different shape, and other means other than bimetal may be used to cause the turbulence plate to protrude into the vortex chamber only when the temperature of the combustion chamber is low.

As described above, according to this invention, in a diesel engine swirl chamber, a turbulence plate is provided between the nozzle cylinder head so as to be able to protrude into the swirl chamber, and the turbulence plate is inserted into the swirl chamber only when the combustion chamber temperature is low. A turbulence plate operating means that protrudes into the interior of the engine is provided, so when the engine is cold, the combustion condition in the vortex chamber is improved and startability is improved, and when the engine is warmed up, the turbulence plate can prevent a decrease in output and fuel efficiency. effective.

[Brief explanation of drawings]

Fig. 1a is a cross-sectional view of the swirl chamber structure of a diesel engine according to an embodiment of this invention when the engine is warmed up, and Fig. 2a is a sectional view taken along line I-I in Fig. 2a, and Fig. 2a is a sectional view of the above embodiment. FIG. 2 is a sectional view taken along the line ■-■ in FIG. 1A when the engine is cold. 1... Cylinder head, 2... Concavity,
3... Enlarged concave portion, 4... Cap, 4a.
...Recessed part of the cap, 6... Vortex chamber, 12.
...Turbulent flow plate, 13... Bimetal (turbulent flow plate moving means).

Claims (1)

[Scope of utility model registration request] In a diesel engine, the mouthpiece is inserted from below into an enlarged recess formed in the lower part of the cylinder head, and the recess of the cylinder head and the recess of the mouthpiece form a substantially spherical swirl chamber. A diesel engine characterized in that a turbulence plate is provided in the vortex chamber so as to be able to protrude therebetween, and a turbulence plate operating means is provided for causing the turbulence plate to protrude into the vortex chamber only when the temperature of the combustion chamber is low. Swirl chamber structure.