JPH06146888A - Controller for high compression ratio engine for vapor fuel - Google Patents

Abstract

PURPOSE:To open a control valve provided between a subsidiary chamber and a main chamber in a high compression ratio engine which uses volatile liquid fuel without requiring any large driving force. CONSTITUTION:A control valve 5 is provided in a connection port 31 between a subsidiary chamber arranged in a cylinder head 11 and a main chamber 2 above a piston 2, and is opened by means of excitation of an electromagnetic mechanism 34 in the upper part of a subsidiary chamber 3, so that in a compression stroke during a high load in an engine, the control valve 5 is opened and closed once by excitation control of the electromagnetic mechanism 34 so as to lead the air from the main chamber 23 into the inside of the subsidiary chamber 3, and then the fuel is injected and ignited to be burnt. Therefore, the pressure inside the subsidiary chamber 3 is increased and the pressure gap between the subsidiary chamber and the main chamber is decreased, so that the control valve is opened even by small driving force.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a controller for a high compression ratio engine for vaporized fuel, which burns a liquid fuel that is volatile easily at a high compression ratio.

[0002]

2. Description of the Related Art It is known that in an internal combustion engine, the theoretical thermal efficiency is increased by increasing the compression ratio of fuel, and in a diesel engine, a compression ratio of about 20 is used to inject light oil of fuel into compressed air for combustion. , To improve the thermal efficiency.

On the other hand, when volatile gasoline is injected into a cylinder like a diesel engine, it vaporizes before mixing with air, making it difficult to mix the vaporized fuel with air, resulting in a temperature rise due to high compression. Therefore, ignition occurs early and knocking occurs. Therefore, a sub-chamber for pre-combustion is provided and connected to the main chamber, a control valve is provided in the connection flow passage to close the sub-chamber, and the air-fuel mixture generated in the sub-chamber is opened by opening the control valve. Attempts are being made to send it to and burn it.

[0004]

When a control valve is provided at the communication port between the sub-chamber and the main chamber as described above and a mixture is produced in the closed sub-chamber, the amount of air is small, so ignition occurs. Without
Although it is possible to use a liquid fuel that easily volatilizes, when the cylinder internal pressure is high, it is difficult to drive the control valve to open, and there is a problem that a large driving force is required to open the control valve.

The present invention has been made in view of such a problem, and an object thereof is to burn a liquid fuel which is easily volatilized at a high compression ratio and to provide a control provided between the sub chamber and the main chamber. It is an object of the present invention to provide a controller for a high compression ratio engine for vaporized fuel, which attempts to open the valve with a small driving force.

[0006]

In order to achieve the above object, according to the present invention, a high compression ratio for vaporized fuel is provided, which is equipped with a sub-chamber for pre-combusting a liquid fuel that is likely to volatilize and which is burned at a high compression ratio. In a control device for an engine, a control valve that is provided in a communication flow path between the sub chamber and the main combustion chamber to open and close the flow path, a valve drive mechanism that drives the control valve to open and close, and an engine at high load And a drive control means for operating the valve drive mechanism to open and close the control valve in the compression stroke of the above.

[0007]

[Operation] When the engine is under high load, the control valve is opened and closed once in the compression stroke to introduce air into the sub-chamber, and then fuel injection is performed to ignite the fuel. Is reduced, and when the control valve is opened near the top dead center, the valve is opened with a small driving force.

[0008]

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

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

In the figure, reference numeral 1 is a cylinder, which is provided with a piston 2 which is slidable up and down, and a cylinder head 11 which is a sub-chamber 3 which serves as a pre-combustion chamber for combustion of readily volatile gasoline or the like.
An intake / exhaust valve 4 is provided. The piston head 21 is made of high-strength and heat-resistant ceramics. The top of the piston head 21 is formed to have a low slope on the side of the sub chamber 3, and the recess 22 is formed in a portion corresponding to the communication port 31 with the sub chamber 3.
Is provided to serve as an air reservoir, and the main fuel chamber 23 is formed together with the upper void of the piston 2.

The sub chamber 3 has a high strength such as silicon nitride,
The heat-resistant and heat-shielding ceramics are formed, and an air layer 32 for heat shield is formed on the outer peripheral wall thereof, and a control valve 5 that moves up and down to open and close the communication port 31 is attached to the central portion. The control valve 5 has a stem 51 supported by a shaft hole 33 in an upper wall portion, and a suction plate 5 mounted on the top portion.
2 is for opening and closing the communication port 31 by a suction force by energizing the electromagnetic mechanism 34 above the sub chamber 3, and a heat shield 35 is arranged between the sub chamber 3 and the electromagnetic mechanism 34. There is.

Reference numeral 6 denotes an injection nozzle, which is attached to the side wall of the sub chamber 3 and injects the volatile fuel from the injection pump 61 into the sub chamber 7. Reference numeral 7 denotes an ignition plug for igniting the fuel by spark discharge. It is used when it is difficult to ignite due to the engine load or the internal temperature of the sub chamber 3.

Reference numeral 8 denotes a controller composed of a microcomputer, which includes an engine rotation sensor 81 and a load sensor 82.
When the respective detection signals from the crankshaft position sensor 83 and the crankshaft position sensor 83 are input, a predetermined calculation is performed, and the electromagnetic mechanism 34, the injection pump, and the spark plug 7 are operated according to the stored map and control procedure.
It is configured to issue an operation command to the.

FIG. 2 is a process flow chart showing an example of the operation of the present embodiment, and FIG. 3 is a curve diagram showing an example of the opening / closing of the control valve and the pressure in the sub chamber in this embodiment. The operation of this embodiment will be described.

In step 1 in FIG. 2, the rotation sensor 8 is used.
1, the engine speed, the engine load, and the crank position of the detection signals from the load sensor 82 and the crankshaft position sensor 83 are input, and the engine load input in step 2 is checked. When the input engine load L is smaller than the predetermined load La, the routine proceeds to step 3 to determine the fuel injection timing and the ignition timing.

Next, in step 4, fuel is injected at the determined time, in step 5, the spark plug 7 is energized to ignite by spark discharge, and the control valve 5 is energized to the electromagnetic mechanism 34 before and after top dead center. Open the valve. Note that this opening of the valve causes a large load of excess air in the sub-chamber due to a small load on the engine, so the pressure in the sub-chamber becomes large due to the combustion of the air-fuel mixture due to ignition, so that the electromagnetic mechanism 34 can be opened even with a small electromagnetic force.

If the engine has a heavy load in step 2 above, the process proceeds to step 7 to determine whether or not it is the compression stroke, and if it is the compression stroke, the routine proceeds to step 8. Here, as shown in FIG. 3, after opening the control valve 5 at a predetermined timing of the compression stroke, it is immediately closed in step 9, then combustion injection is performed and ignition is performed by the spark plug 7, and before and after top dead center. The control valve 5 is opened at (steps 10 to 12).

In this case, if the control valve 5 is opened in the compression stroke, a large amount of air from the main chamber enters the sub chamber, mixes with the injected fuel, and is activated well. The control valve 5 can be easily opened due to the increase in the room pressure.

Next, in step 13, it is checked whether or not it is in the exhaust stroke, and in the case of the exhaust stroke, the control valve 5 is closed and the process returns to the first flow.

The alternate long and short dash line curve shown in FIG. 3 represents the pressure in the sub chamber from the compression stroke to the exhaust stroke.

Although the present invention has been described with reference to the above embodiments, various modifications can be made within the scope of the gist of the present invention, and these modifications are not excluded from the scope of the present invention.

[0022]

According to the present invention as in the above embodiments,
A control valve is provided between the sub-chamber and the main chamber to inject fuel into the sub-chamber, activate the fuel in the sub-chamber and burn it in the main chamber. At the same time, when the engine is under heavy load, the control valve is opened and closed once in the compression stroke to introduce air into the sub-chamber, injecting fuel and burning it to increase the sub-chamber pressure. There is an advantage that the control valve can be opened even with a small driving force by reducing the pressure difference.

[Brief description of drawings]

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

FIG. 2 is a process flow chart showing an example of the operation of the present embodiment.

FIG. 3 is a curve diagram showing opening / closing of a control valve and pressure in a sub chamber in the present embodiment.

[Explanation of symbols]

 1 ... Cylinder 2 ... Piston 3 ... Sub-chamber 5 ... Control valve 8 ... Controller 23 ... Main chamber 31 ... Communication port 34 ... Electromagnetic mechanism 82 ... Load sensor

Claims (2)

[Claims] 1. A controller for a high-compression-ratio engine for vaporized fuel, which comprises a sub-chamber for inhaling and combusting a liquid fuel that is easily volatilized to burn at a high compression ratio. A control valve that is provided in the communication flow path between the valves and that opens and closes the flow path, a valve drive mechanism that drives the control valve to open and close, and a control valve that operates the valve drive mechanism in the compression stroke of the engine according to the load. A controller for a high compression ratio engine for vaporized fuel, comprising drive control means for opening and closing. 2. The controller for a high compression ratio engine for vaporized fuel according to claim 1, wherein the valve drive mechanism is an electromagnetic mechanism that is attracted by an electromagnetic force to open the valve.