JPH06146889A - High compression ratio methanol engine - Google Patents

Abstract

(57) [Summary] [Purpose] A control valve is provided at the communication port between the auxiliary chamber and the main chamber of the methanol engine, and when the engine is partially loaded, the control valve is closed during the expansion stroke and some combustion gas remains. Then, the injected fuel is activated by the high temperature and high pressure gas. [Structure] The outer space of the sub chamber 3 is surrounded by an air layer 32 to block heat and maintain a high temperature, and a control valve 4 is arranged between the sub chamber 3 and the main chamber 12 to open and close the valve by energizing an electromagnet 5. When the engine is partially loaded, the control valve 4 is closed during the expansion stroke to leave the combustion gas, and the injected methanol is activated by the high temperature and high pressure combustion gas, and the main valve is opened by opening the control valve 4. It is blown out to 12 and burned sufficiently to improve the combustion under partial load.

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 methanol engine which improves the combustion state of methanol under partial load.

[0002]

2. Description of the Related Art Fossil fuels such as gasoline and light oil are usually used as engine fuels, but the exhaust gas contains many substances that pollute the atmosphere such as nitrogen oxides and black smoke. Engines for fuel are being developed.

[0003]

In an engine using methanol as a fuel, although the soot and nitrogen oxides in the exhaust gas can be reduced, the latent heat of vaporization of methanol itself is high and the ignition temperature is high. When the temperature is high, the ignition is likely to occur when the temperature of the combustion chamber is high, but when the load is low, the wall temperature of the combustion chamber is low and it is difficult to vaporize and activate methanol, resulting in poor combustion.

The present invention has been made in view of the above problems, and an object thereof is to provide a control valve at a communication port between a sub-chamber for pre-combusting methanol and a main chamber, and to control opening / closing of the control valve. The object is to provide a high compression ratio methanol engine that intends to improve the combustion state of methanol under partial load.

[0005]

According to the present invention, in order to achieve the above object, a control valve for opening and closing a communication port between a main chamber and a sub chamber for pre-combusting methanol as fuel for an engine. An electromagnet that opens and closes the control valve by an electromagnetic force, a sub chamber temperature holding unit that holds the internal temperature of the sub chamber at a high temperature, a load detection unit that detects the load state of the engine, and A high compression ratio methanol engine is provided with a valve opening / closing control means for opening the control valve at the end of the compression stroke of the engine and closing the control valve during the expansion stroke in response to the signal from the load detection means. Provided.

[0006]

[Function] When the methanol engine is partially loaded, the control valve is closed and the sub-chamber is closed during the expansion stroke, so that a part of the high-temperature and high-pressure combustion gas remains and the fuel is injected into this gas. When the activation of the fuel progresses and the control valve is opened, the combustion in the main chamber is efficiently performed even at the partial load.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a structural block diagram showing an embodiment of a high compression ratio methanol engine according to the present invention.
FIG. 4 is a curve diagram of an example showing the relationship between the opening and closing of the control valve of the combustion chamber and the operating state of the engine in this embodiment.

In FIG. 1, reference numeral 1 denotes a cylinder, which is provided with a piston 2 which is vertically slidable, and which is an upper cylinder head 1.
A sub-chamber 3 for pre-combusting methanol, an intake / exhaust valve 4 and the like are attached to 1. Ceramics having high strength and heat resistance are used for the piston head 21 on the upper surface of the piston 2, and the top of the piston head 21 is provided with a gently inclined surface so that the lower portion of the sub-chamber 3 is lowered and further below the sub-chamber 3. The portion corresponding to the communication port 31 is provided with the depression 22 to form an air pocket.

The sub chamber 3 has a high strength such as silicon nitride,
It is made of heat-resistant and low-heat-conducting ceramics, an air layer 32 for heat insulation is circulated on its outer peripheral wall, and a control valve 4 for opening and closing a communication port 31 with the main chamber 12 is arranged in the central portion. The stem 41 of the control valve 4 is supported movably up and down by a shaft hole 33 in the central portion of the upper wall of the sub chamber 3, and when it descends, the communication port 31 of about 3 to 5% of the piston area is opened.

A suction plate 53 made of a magnetic material is attached above the stem 41, and when the coil 51 of the electromagnet 5 disposed above the sub chamber 3 is energized, the suction force is generated by the electromagnetic force generated in the core 52. 53 is configured to be sucked. In addition, 34 is a heat shield, and is the shaft hole 3 of the sub chamber.
It is attached above the third chamber 3 and shields heat between the sub chamber 3 and the electromagnet 5.

Reference numeral 6 denotes an injection nozzle, which is attached to the side wall of the sub chamber 3 and supplies methanol sent from the injection pump 61 to the sub chamber 3.
Is sprayed inside, and an injection command to the injection pump 61 is issued from the controller 7.

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

Next, the operation of the present embodiment thus constructed will be described with reference to the curve diagram shown in FIG. 2. The control valve 4 is opened at the end of the compression stroke of the engine, and the inside of the sub chamber 3 is opened. The ignition flame ignites the air-fuel mixture that fills the main chamber 12
It combusts when mixed with fresh air remaining in the air. Then, when the control valve that is normally closed at the end of the exhaust stroke is closed near the bottom dead center in the expansion stroke, high-temperature and high-pressure combustion gas remains inside the sub chamber 3 and the exhaust stroke is increased. The methanol injected in the final stage of activation is activated even when the load is low, or changes from CH ₃ OH to 2H ₂ + CO. Then, when the control valve 4 is opened in the next stroke, the combustion suppresses the generation of NO _X due to the rich air-fuel mixture, and further, the homogeneous air-fuel mixture and the flame are blown into the main chamber 12 due to the explosive force for premixing. Combustion in a close state will be performed. Therefore, fuel efficiency is improved even with partial load, and combustion can be obtained with less exhaust gas.

Further, in the case of high engine load, as shown in the curve diagram of FIG. 2, even if the closing of the control valve opened from the end of the compression stroke to the middle of the expansion stroke is delayed from the partial load, the combustion chamber Since the temperature is high, it is easily ignited and sufficient combustion is performed.

Although the above description of the embodiments of the present invention has been given, various modifications are possible within the scope of the gist of the present invention, and these modifications are not excluded from the scope of the present invention.

[0017]

According to the present invention as in the above embodiments,
During partial expansion of the methanol engine, the control valve at the communication port is closed and the sub-chamber is closed during the expansion stroke.Therefore, high-temperature, high-pressure combustion gas remains inside, and when methanol is injected into this gas. , activation is performed, at the time of opening of the next control valve is generated suppressed of the NO _X for its combustion rich mixture, further main chamber air-fuel mixture blown to efficiently combusted to part load combustion The effect is improved.

[Brief description of drawings]

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

FIG. 2 is a curve diagram of an example showing a relationship between opening / closing of a control valve and an operating state of an engine in the present embodiment.

[Explanation of symbols]

 1 ... Cylinder 3 ... Sub-chamber 4 ... Control valve 5 ... Electromagnet 7 ... Controller 12 ... Main chamber 31 ... Communication port 32 ... Air layer 72 ... Engine load sensor

Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display area F02M 25/07 580 C

Claims (3)

[Claims] 1. A control valve for opening and closing a communication port between a main chamber and a sub chamber for pre-combusting methanol as fuel for an engine,
An electromagnet that opens and closes the control valve by an electromagnetic force, a sub chamber temperature holding unit that holds the internal temperature of the sub chamber at a high temperature, a load detection unit that detects the load state of the engine, and the control described above. A high compression characterized by comprising a valve opening / closing control means for opening the valve at the end of the compression stroke of the engine and closing the control valve in the middle of the expansion stroke in response to the signal from the load detection means. Specific methanol engine. 2. The high compression ratio methanol engine according to claim 1, wherein said valve opening / closing control means closes the valve earlier than in full load when in partial load by a signal from the load detecting means. 3. The sub-chamber temperature holding means uses ceramics having high strength and low thermal conductivity as a material of the sub-chamber, and the outer wall of the sub-chamber is surrounded by an air layer.
High compression ratio methanol engine described.