JPH0514550U - Combustion device for direct injection diesel engine - Google Patents

Abstract

(57) [Summary] [Object] An object of the present invention is to provide a direct injection diesel engine which suppresses NO _X emissions and has high combustion efficiency. A combustion apparatus for a direct injection type diesel engine of the present invention is provided with a multi-hole fuel valve 4 facing a combustion chamber 1 recessed in a piston top surface and opened in an exhaust port 6 of a cylinder head. The exhaust gas introduced through the exhaust gas bypass pipe 9 is increased in pressure by the electronic control unit 15 and the throttle valve 14 by the pressure increasing piston 8a whose fuel oil pressure of the fuel injection pump is controlled according to the load of the engine, and the fuel in the combustion chamber is increased. It is characterized by having an automatic injection valve 17 for injecting in the valve direction.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a combustion device for a direct injection diesel engine.

[0002]

[Prior Art]

 FIG. 2 is a vertical sectional view of a combustion chamber of a conventional direct injection diesel engine, and FIG. 3 is a plan view of the conventional combustion chamber. A cylindrical combustion chamber 1 is recessed in the center of a piston 2, and a fuel valve 4 having multiple injection holes attached to a cylinder head 3 radiates a fuel spray 5 radially from the center of the combustion chamber toward the wall surface of the combustion chamber. It was injected and ignited and burned.

[0003]

[Problems to be solved by the device]

However, the fuel injected from a conventional fuel injection valve, by introducing air surrounding the combustion chamber from the injection initial high percentage begins to burn near stoichiometric, nitrogen oxides Ri a high combustion gas temperature NO _X Was the cause of a large amount of.

An object of the present invention is to solve the above problems of the conventional engine and to provide a direct injection diesel engine which suppresses NO _X emission and has a good combustion efficiency.

[0005]

[Means for Solving the Problems]

 a) The combustion device for a direct injection diesel engine of the present invention comprises a multi-hole fuel valve 4 arranged to face a combustion chamber 1 recessed in the piston top surface, and an exhaust port of a cylinder head. A combustion gas compression device 8 for pressurizing a gas introduced through an exhaust gas bypass pipe 9 opened in 6, and an automatic injection valve 17 for injecting the exhaust gas compressed by the compression device toward the fuel valve in the combustion chamber. It is characterized by having. b) The combustion gas compression device 8 controls the fuel oil pressure of the fuel injection pump according to the load of the engine by the electronic control device 15 and the throttle valve 14 to apply the exhaust gas to the pressure boosting piston 8a to press the automatic injection valve 17 It is characterized by pumping.

[0006]

[Action]

Since the present invention is constructed as described above, it operates as follows. Exhaust gas is pressurized above the pressure in the combustion chamber, and is retained near the fuel valve via the automatic injection valve, so that fuel spray immediately after jetting from the fuel valve reaches while introducing the exhaust gas and suppresses air introduction. Since the combustion starts at NOx, the NO _x production reaction is suppressed. Further, since the electronically controlled throttle valve 14 is provided in the oil passage between the exhaust gas compression device and the fuel injection pump, the supply of fuel oil to the exhaust gas compression device can be adjusted according to the load of the engine.

[0007]

【Example】

 A first embodiment of the present invention will be described with reference to FIG. In the figure, when the combustion process is completed in the combustion chamber 1, the combustion gas in the cylinder is discharged to the outside of the engine from the exhaust port 6, but it is controlled by the hydraulic pressure of the fuel injection pump linked to the crankshaft (not shown). The pressure-increasing piston 8a in the exhaust gas compression device 8 moves to the right in the intake process due to the return coil spring 8b of the pressure-increasing piston and the decrease operation of the injection pump oil pressure, and the exhaust gas in the exhaust port 6 moves. Through the exhaust gas bypass pipe 9 into the exhaust gas compression device cylinder 8c. When the engine enters the compression process, the plunger 7a in the fuel injection pump 7 which is interlocked also serves as a compressor to compress and pressurize the fuel oil in the pump cylinder 7c. The pressurized fuel is divided into two directions by a branch pipe 10 through an injection pipe 11, one injection pipe 12 through a fuel valve 4 to the combustion chamber, and the other is controlled by an injection pipe 13 and an electronic control unit 15. The pressure-increasing piston 8a supplied to the exhaust gas compression device 8 via the throttle valve 14 is moved leftward so that the exhaust gas in the pressurizing device cylinder 8c becomes higher in pressure than the engine cylinder internal pressure, and becomes high in pressure. The exhaust gas is injected toward the injection port of the fuel valve 4 in the combustion chamber 1 through the injection pipe 16 and the automatic injection valve 17.

The exhaust gas 18 injected toward the fuel valve 4 drifts locally near the fuel valve, while the fuel spray 5 supplied through the injection pipe 12 and the fuel valve 4 is directed toward the wall surface of the combustion chamber. However, after passing through the atmosphere of the exhaust gas 18, it reaches the wall surface of the combustion chamber. Fuel spray 5 which is injected into the combustion chamber 1 from the fuel valve 4 will initially continue to develop with write attempts to wind the exhaust gas 18, to begin to burn in a state mixed with the air is suppressed, of the NO _X Generation is suppressed and NO _X in exhaust gas can be reduced. Also, after the fuel spray has developed and passed through the exhaust gas region, a large amount of air is present, so mixing with the air proceeds, and further collision with the wall surface of the combustion chamber promotes mixing with the air, and eventually complete mixing occurs. Burning is measured.

Further, an electronic control unit 15 and a throttle valve 14 are provided in an oil passage between the fuel injection pump 7 and the exhaust gas compression device 8 to control the amount of fuel supplied to the exhaust gas compression device 8 according to the load of the engine. You can control.

[0010]

[Effect of the device]

Immediately after being ejected from the fuel valve, the fuel spray develops while introducing the exhaust gas and starts to burn with the air introduction suppressed, so that the NO _X production reaction is suppressed. In addition, an electronically controlled throttle valve is installed in the oil passage between the exhaust gas compression device and the fuel injection pump, so the supply of fuel oil to the exhaust gas compression device is adjusted according to the engine load to supply exhaust gas to the combustion chamber. You can adjust the quantity.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a direct injection diesel combustion device according to a first embodiment of the present invention,

FIG. 2 is a longitudinal sectional view of a combustion chamber of a conventional direct injection diesel engine,

FIG. 3 is a plan view of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Combustion chamber, 4 ... Fuel valve, 5 ... Fuel spray, 6 ... Exhaust port, 7 ... Fuel pump, 8 ... Exhaust gas compression device, 8a ... Pressure boosting piston, 9 ... Exhaust gas bypass pipe, 10 ... Fuel oil branch Pipe, 14 ... Throttle valve, 15 ... Electronic control device, 16 ... Injection pipe, 17 ... Automatic valve, 18 ... Exhaust gas.

Claims (2)

[Scope of utility model registration request] 1. A combustion chamber (1) recessed in a top surface of a piston.
And a multi-hole fuel valve (4) arranged so as to face the combustion chamber
In a direct injection diesel engine equipped with an exhaust gas bypass pipe (9) opened in an exhaust port (6) of a cylinder head, and a combustion gas compression device (8) for pressurizing gas introduced through the exhaust gas bypass pipe. ) And an automatic injection valve (17) for injecting the exhaust gas compressed by the compression device toward the fuel valve in the combustion chamber, the combustion device for a direct injection diesel engine. 2. A combustion gas compression device (8) controls a fuel oil pressure of a fuel injection pump (7) according to an engine load by an electronic control device (15) and a throttle valve (14) to increase a piston. In addition to (8a), exhaust gas is pressurized and pressure-fed to an automatic injection valve (17).