JPS6118189Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a stratified air charge engine that uses methanol as fuel.

BACKGROUND ART Conventionally, a stratified air charge engine that uses gasoline as fuel has been proposed as shown in FIG. That is, a thin cylindrical part 2a is formed at the upper end of the cylinder body 2 into which the piston 12 is fitted, and the cylinder head 8 is fitted into this to form the main combustion chamber 1 inside.
3 is formed, and a pre-combustion chamber 3 that is connected to the side of this main combustion chamber 13 via a passage 9 is formed. This pre-combustion chamber 3 is approximately spherical and has a cylinder head 8.
A half of the pre-combustion chamber 3 and a buried body 7 with a passage 9 formed on the main body side are fitted and fixed together. Attach the fuel injection valve 6 and spark plug 5 facing the combustion chamber 3.

When gasoline fuel is used in the above-mentioned engine, gasoline is easily vaporized and a mixture that is easily combustible is formed, but when methanol fuel is used, the following problems occur. In other words, while gasoline contains low-boiling point components, methanol has a high boiling point of 64.7℃, has a large latent heat of vaporization, and has low vapor pressure, making it difficult to vaporize the fuel and cause combustion. This makes it difficult to start the engine when the outside temperature is below 17°C. As a general condition for vehicles to be widely used, an engine that is easy to start even at an outside temperature of around -25°C is required.

In addition, as shown in Special Publication No. 56-38771,
Some gasoline engines with a pre-chamber have the fuel injection nozzle and spark plug placed inside the pre-chamber, but with this configuration, when alcohol fuel is used, the fuel does not vaporize in cold weather, making it difficult to start. .

Therefore, the purpose of this invention is to arrange a heating element or preheating plug at the bottom of the pre-combustion chamber, and by spraying the fuel so that it hits this heating element and vaporizing it, the methanol stratified intake air can be easily started even in cold weather. The purpose is to provide engines.

For this reason, the configuration of the present invention is to provide a pre-combustion chamber on the side of the top end of the cylinder, place a pre-combustion plug horizontally on the bottom wall of the pre-combustion chamber, and arrange a fuel injection valve opposite the pre-heat plug. At the same time, an ignition plug is arranged between the fuel injection valve and the preheating plug.

The configuration of the present invention will be explained based on an example.
As shown in FIG. 2, a preheating plug 1 is disposed at the bottom of a precombustion chamber 3 whose inner wall surface is approximately spherical, and a fuel injection valve 6 is disposed opposite to the preheating plug 1.
The spark plug 5 is placed at an appropriate location in the pre-combustion chamber 3. When a general rod-shaped preheating plug 1 is used, it is placed horizontally so that its circumferential surface does not protrude too much from the wall surface of the precombustion chamber 3, and is placed at a position where the injected fuel reaches. The other configurations are similar to those of the conventional stratified air intake engine, and similar components are designated by common reference numerals.

According to the present invention, when starting the engine in a low temperature environment, the preheating plug 1 is first heated to about 800°C. Next, if methanol fuel is directly injected from the injection valve 6 toward the red-hot preheating plug 1, the preheating plug 1
The fuel that collided with the pre-combustion chamber 3 immediately vaporized and
The fuel that has collided with the wall flows to the bottom along the wall of the precombustion chamber, touches the preheating plug 1 at the bottom, and is evaporated and vaporized. The vaporized fuel mixes with air to form an ignitable mixture. The spark from the ignition plug 5 ignites at an appropriate time to enable starting. After the engine is started, the preheating plug 1 reduces the amount of current supplied to the engine to lower the combustion temperature for a while to quickly warm up the engine.

In the present invention, since the preheating plug 1 is placed at the bottom of the precombustion chamber 3 and at the position where the fuel injected from the fuel injection valve 6 reaches, most of the injected fuel directly contacts the preheating plug 1 and evaporates. While vaporizing, the remaining fuel that did not touch the preheating plug 1 accumulates at the bottom of the precombustion chamber 3, where it comes into contact with the preheating plug 1.
Fuel vaporization is complete. In addition, since the preheating plug 1 is placed horizontally so as not to protrude too much from the wall surface of the precombustion chamber 3, it prevents gas behavior (swirl or squish) in the combustion chamber when the present invention is applied to a conventional engine. Also, pre-combustion chamber 3
Since the volume of the compressor does not change significantly, the compression ratio is not affected.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a main part of a conventional stratified air charge engine using gasoline as fuel, and FIG. 2 is a longitudinal sectional view of main parts of a stratified air charge engine using methanol as fuel according to the present invention. 1: Preheating plug, 2: Cylinder body, 3: Precombustion chamber, 4: Split body, 5: Spark plug, 6: Fuel injection valve,
7: Buried body, 8: Cylinder head, 9: Fuel passage, 12: Piston, 13: Main combustion chamber.

Claims (1)

[Scope of utility model registration request] A pre-combustion chamber is provided on the side of the top end of the cylinder, a pre-heating plug is disposed horizontally on the bottom wall of the pre-combustion chamber, a fuel injection valve is arranged opposite to the pre-heating plug, and the fuel injection valve and the A methanol stratified air supply engine characterized by having an ignition plug arranged between a preheating plug and a preheating plug.