JPH084534A - Combustion chamber of diesel engine - Google Patents

Abstract

PURPOSE:To provide a combustion chamber wherein mixture property of air and fuel can be improved more. CONSTITUTION:Fuel spray 10 injected from an injection nozzle 3 is hit against protruding parts 11 so that mixture property of the fuel spray 10 and air is improved by providing the protruding parts 11 projected in the channel of the fuel spray 10 injected from the injection nozzle 3 on the lower surface of valves 4 provided in positions by which the injection nozzle 3 is surrounded thereby. Further, the direct advance force of the fuel spray 10 is lowered by its hit against the protruding parts 11 so as to reduce the quantity of the fuel spray 10 stuck on the inner surface of a cavity 9.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a combustion chamber of a diesel engine, and more particularly to a combustion chamber effective for improving mixing of fuel injected from an injection nozzle and air in the combustion chamber.

[0002]

2. Description of the Related Art Diesel engine exhaust gas (NOx)
If the timing retard is performed to improve the fuel consumption, the amount of black smoke generated increases and the fuel consumption deteriorates. In order to avoid such a situation, it is effective to increase the fuel injection pressure to further refine the fuel spray injected into the combustion air to promote mixing with the air. However,
Even if the high-pressure injection is performed in this way, there is a limit in promoting the mixing of the fuel and the air, so that some measure has been required.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object thereof is to provide a combustion chamber capable of further improving the mixing property of air and fuel.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention is directed to a lower surface of a valve provided at a position surrounding an injection nozzle, and a projection protruding into a flow path of fuel spray injected from the injection nozzle. It is characterized by the provision of a section.

[0005]

The fuel spray injected from the injection nozzle gradually diffuses and burns in the cavity while introducing the surrounding air. At this time, since the projection provided on the lower surface of the valve projects into the flow path of the fuel spray, the flow of the fuel spray generated in the cavity is disturbed by the projection. Therefore, the ambient air is efficiently introduced into the fuel spray, and the mixing property of the fuel and the air is improved. Further, the collision force with the projection reduces the straight-ahead force of the fuel spray and reduces the reaching distance, so the amount of fuel spray adhering to the inner surface of the cavity is reduced and The quantity also decreases.

[0006]

Embodiments of the present invention will be described in detail below with reference to the drawings. 1 is a sectional view showing an embodiment of a combustion chamber of a diesel engine according to the present invention, and FIG. 2 is a schematic plan view of FIG. 1 showing a relationship between fuel spray injected from an injection nozzle and a protrusion provided on a valve. is there.

In these figures, an injection nozzle 3 is attached to a central portion of a cylinder head 2 which covers an upper end portion of a cylinder liner 1, and a valve 4 is attached to a position surrounding the injection nozzle 3. 5 is intake port, 6 is exhaust port,
7 is a sealing material. Further, a cavity 9 is recessed in the top surface of a piston 8 slidably attached to the cylinder liner 1 to form a combustion chamber.

A projection 11 is provided on the lower surface of the valve 4 so as to project into the flow path of the fuel spray 10 injected from the injection nozzle 3. The protrusion 11 is formed by molding a relatively lightweight and heat-resistant material such as ceramic or stainless steel into the base portion of the valve 4
Is embedded in the lower surface of the.

Therefore, the fuel spray 10 injected from the injection nozzle 3 mixes with the air existing in the cavity 9 and gradually diffuses and burns in the cavity 9. At this time, the projection 11 provided on the lower surface of the valve 4 projects into the flow path of the fuel spray 10.

For this reason, the flow of the fuel spray 10 generated inside the cavity 9 is divided into the left and right directions by the projection 11 to enhance the dispersibility thereof, and the fuel spray 10 is collided with the projection 11. Turbulence is generated inside the flow of. Therefore, the ambient air is efficiently introduced into the fuel spray 10, and the mixing property of the fuel and the air is improved.

Further, the collision with the projection 11 makes the liquid droplets forming the fuel spray 10 finer and promotes vaporization, so that the combustion efficiency is improved and quiet combustion is performed. Moreover, the fuel spray 1 is generated by the collision with the protrusion 11.
Since the straight traveling force of 0 is reduced and the reaching distance is corrected to be reduced, the amount of the fuel spray 10 adhering to the inner surface of the cavity 9 is reduced, and the amount of unburned components contained in the exhaust gas is also reduced.

In the embodiment, the base of the conical tip is embedded in the lower surface of the valve 4 to form the projection 11, so that the fuel spray 10 and the projection 11 associated with the rotation of the valve 4 are formed.
However, when the valve 4 does not rotate, it is possible to increase the occurrence of turbulence by forming the protrusion 11 with another pyramid-shaped tip or a tip having an arc cross section. Further, the protrusion 11 does not necessarily have to be a chip, and the lower surface of the valve 4 may be formed by protrusion.

[0013]

As is apparent from the above description, according to the combustion chamber of the diesel engine of the present invention, the fuel droplets forming the fuel spray are made finer by the collision with the protrusion provided on the lower surface of the valve. The fuel-air mixability is improved because the dispersion of the fuel spray and the introduction efficiency of ambient air to the fuel spray can be made higher while promoting vaporization. Further, the amount of the fuel spray adhering to the inner surface of the cavity is reduced due to the straightening force of the fuel spray being attenuated and corrected by the collision with the protrusion, so that the amount of unburned components contained in the exhaust gas is also reduced.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of a combustion chamber of a diesel engine according to the present invention.

2 is a schematic plan view of FIG. 1 showing a relationship between fuel spray injected from an injection nozzle and a protrusion provided on a valve.

[Explanation of symbols]

 1 Cylinder Liner 2 Cylinder Head 3 Injection Nozzle 4 Valve 5 Intake Port 6 Exhaust Port 7 Sealant 8 Piston 9 Cavity 10 Fuel Spray 11 Projection

Claims (1)

[Claims] 1. A combustion chamber of a diesel engine, comprising: a projection provided on a lower surface of a valve provided at a position surrounding the injection nozzle, the projection protruding into a flow path of fuel spray injected from the injection nozzle.