JP2998050B2 - High compression ratio gasoline engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high compression ratio gasoline engine having a high compression ratio in which a control valve is disposed in a sub-chamber for pre-combustion.

[0002]

2. Description of the Related Art In general, as shown in FIG. 2 showing the theoretical thermal efficiency (.eta.th), the higher the compression ratio (.epsilon.), The larger the performance of the engine.

Therefore, an engine using gasoline as a fuel is operated with a compression ratio of about 8 to 10, but if the compression ratio is further increased, knocking occurs and sufficient performance cannot be obtained.

Further, in a diesel engine, injecting fuel into compressed air, the compression ratio is increased to about 18 to 23 to improve the performance.

[0005]

As described above, in a gasoline engine, a so-called pre-mixed gas in which fuel and air are mixed is generated and sucked into a cylinder, and when the temperature of the compressed air is increased, ignition occurs at an early stage. Knocking occurs, and it is difficult to increase the compression ratio more than before.

The present invention has been made with a focus on the compression ratio of such a gasoline engine. The object of the present invention is to provide a sub-combustion chamber in addition to the main combustion chamber, and to provide a control valve at the communication port thereof to achieve high compression. The aim is to provide a gasoline engine of a ratio.

[0007]

According to the present invention, there is provided a control valve for opening and closing a communication port between a sub-chamber for performing pre-combustion and a main chamber, and opening and closing the control valve. A driving means for driving, a sub-chamber temperature holding means for holding the inner wall temperature of the sub-chamber at a high temperature, an injection nozzle for spraying gasoline into the sub-chamber, and a control valve for controlling the exhaust and intake strokes of the engine. A high compression ratio gasoline engine provided with valve opening / closing and fuel injection control means for closing and opening the valve at the end of the compression stroke and immediately injecting fuel after closing in the exhaust stroke.

[0008]

[Function] The sub-chamber, which performs pre-combustion, has a heat shield structure to maintain the inside at a high temperature, and a control valve is provided at the communication port with the main chamber. Gasoline is generated in the air-fuel mixture activated in the high-temperature sub-chamber,
Although the time of ignition is NO _X for rich state is suppressed, the control valve at the end of the compression stroke is released flame blow to the main chamber, explosive combustion takes place in the reaction with air.

[0009]

Next, an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of a high compression ratio gasoline engine according to the present invention. In the figure, reference numeral 1 denotes a cylinder, which is a piston 2 slidable up and down.
And a sub chamber 3 serving as a pre-combustion chamber in the cylinder head 11.
And an intake / exhaust valve 4. A high-strength, heat-resistant ceramic is used for the piston head 21. The top of the piston head 21 is an inclined surface so that the lower part of the sub-chamber 3 is formed low. A recess 22 is provided to form an air pocket.

The sub-chamber 3 has a high strength such as silicon nitride, for example.
It is made of heat-resistant and heat-insulating ceramics, and its outer peripheral wall is provided with a heat-shielding air layer 32, and a central portion is provided with a control valve 4 for opening and closing a communication port 31 with the main chamber 12, The control valve 4 has a stem 41 supported by a shaft hole 33 at the center of the upper wall of the sub-chamber 3 so as to be vertically movable. A heat insulating material 34 is attached above the shaft hole 33 for heat insulation.

An electromagnetic device 5 for controlling the opening and closing of the control valve 4 is disposed above the stem 41.
The control valve 4 is opened by the core 52 sucking the suction plate 53 attached to the stem 41 by energizing the coil 51.

Reference numeral 6 denotes an injection nozzle which is attached to the side wall of the sub-chamber 3 and sprays fuel from the injection pump 61 into the sub-chamber 3. A fuel injection command to the injection pump 61 is issued from the controller 7. You.

The controller 7 is composed of a microcomputer. When detection signals from the engine rotation sensor 71, load sensor 72, and crankshaft position sensor 73 are input, predetermined calculations are performed, and the injection pump 61 is operated according to the stored control procedure. A command is issued to the electronic device 5 and the electromagnetic device 5.

Next, the operation of this embodiment constructed as described above will be described. During operation of the engine, the control valve 4 is closed during the intake stroke, fresh air is sucked from the intake valve, flows into the cylinder, and is compressed. Fresh air is compressed in the process. Then, at the end of the compression stroke, the control valve 4 is energized by energizing the electromagnetic device 5.
Is opened, but the injection nozzle 6 previously provided in the sub chamber 3 is opened.
Is activated by the exhaust gas remaining in the sub-chamber 3, and the air-fuel mixture and the fresh air mix to start combustion immediately. In this case, the control valve 4 is opened during the expansion stroke and closed during the exhaust stroke, but immediately after this closing, the fuel is sprayed from the injection nozzle 6. As a result, it is activated and ignited simultaneously with the inflow of fresh air.

[0016] Then, for burning at the time of the ignition fuel is rich state, generation of the NO _X is suppressed, the flame blown from connecting port 31 to the main chamber 12, the combustion reacts with the air in the main chamber portion Complete.

Therefore, even if the compression ratio is high, the combustion is performed smoothly, and the semi-activated fuel gas is efficiently burned in the main chamber 12.

Although the present invention has been described with reference to the above-described embodiment, various modifications are possible within the scope of the present invention, for example, using a camshaft or a gear device as a control valve driving means. These modifications are not excluded from the scope of the present invention.

[0019]

According to the present invention as in the above embodiment,
The pre-combustion sub-chamber has a heat shield structure and a control valve is installed at the communication port between the main chamber and the fuel injected after closing during the engine exhaust stroke is activated in the high-temperature sub-chamber. have been mixed but are ignition of gas and generation of the NO _X for rich state is suppressed, the control valve at the end of the compression stroke is released, explosively flames and the air-fuel mixture blown into the main chamber There is an effect that smooth combustion is performed even if combustion is performed and the compression ratio is increased.

[Brief description of the drawings]

FIG. 1 is a configuration block diagram showing one embodiment of a high compression ratio gasoline engine according to the present invention.

FIG. 2 is an equation diagram showing thermal efficiency.

[Description of Signs] 1 ... Cylinder 2 ... Piston 3 ... Sub chamber 4 ... Control valve 5 ... Electromagnetic device 6 ... Injection nozzle 31 ... Communication port 32 ... Air layer

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) F02B 19/02 F02B 19/16 F02F 1/24 F02D 15/04

Claims (3)

(57) [Claims] 1. A control valve for opening and closing a communication port between a sub-chamber for performing pre-combustion and a main chamber, a driving means for opening and closing the control valve, and maintaining the inner wall temperature of the sub-chamber at a high temperature. Sub-chamber temperature holding means, an injection nozzle for spraying gasoline into the sub-chamber, and the control valve closed in the exhaust and intake strokes of the engine and opened at the end of the compression stroke, and the exhaust gas is discharged in the exhaust stroke. A high compression ratio gasoline engine comprising a valve opening and closing and fuel injection control means for injecting fuel immediately after closing. 2. The high compression ratio gasoline engine according to claim 1, wherein an electromagnetic device driven by using an electromagnetic force is used as said driving means. 3. The sub-chamber temperature holding means uses a high-strength, heat-resistant and low-thermal-conductivity ceramic material for the sub-chamber and forms an air layer for heat insulation on the outer wall of the sub-chamber. The high compression ratio gasoline engine according to claim 1, wherein