KR0184165B1 - Gasoline engine for a car having a squash piston - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct gasoline engine for automobiles having a squash piston, wherein when the engine is operated at theoretical performance ratios, the injection of fuel is carried out by the injector 8 to be mounted in the combustion chamber 7 to vaporize fuel dispersed therein ( 7) Cooling improves the filling efficiency of the intake air, lowers the combustion temperature, suppresses knocking, increases the compression ratio, improves the engine output by more than 10%, and directly cools the fuel in the combustion chamber 7 by cold starting. It is possible to operate at the theoretical theoretical fuel ratio, and accordingly the generation of carbon monoxide is reduced, and the fuel is not in contact with the port wall during acceleration / deceleration operation, so precise air-fuel ratio control is possible, thereby reducing hydrocarbon emissions, and fuel injected from the injector 8. Since the combustion is all in the combustion chamber 7 is converted to the output is to improve the response of the engine to improve the operability.

Description

Automotive direct gasoline engine with squash piston

1a, b, c are schematic cross-sectional views and side sectional and plan views thereof of a direct gasoline engine having a squash piston in accordance with the present invention;

2a and b are cross-sectional state diagrams schematically showing the injection state of the fuel in the direct gasoline engine of the present invention at low and high loads,

3 is a graph showing fuel injection for each engine load and rotational speed.

4 is a graph showing the air-fuel ratio in consideration of the engine load and the number of revolutions.

5 is a graph showing a section in which the fuel and the piston in contact with the fuel injection timing.

6 is a graph showing the pumping loss in lean burn.

7 is a schematic cross-sectional view of a conventional gasoline engine.

* Explanation of symbols for main parts of the drawings

1: intake valve 2: exhaust valve

3: spark plug 4: cylinder head

5: cylinder 6: piston

6a: recess 6b: protrusion

7: combustion chamber 8: injector

[Industrial use]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a direct gasoline engine for automobiles having a squash piston, in particular, to improve fuel efficiency due to lean combustion at low load of the engine, and to operate at theoretical performance ratio at high load, thereby improving engine output and exhausting. The present invention relates to a direct gasoline engine for automobiles having squash pistons that can achieve the effect of reducing gas.

Conventional Technology and Issues

In general, in the gasoline engine of an automobile, an injector 12 for supplying fuel into the combustion chamber 11 is mounted on the intake port 14 side of the intake manifold 13, as shown in FIG. 12) Injection of fuel through the intake stroke is performed while the intake valve 15 is closed, and fuel is injected into the intake port 14, and the fuel injected into the intake port 14 is in the next intake stroke. As the intake valve 15 is opened, it is introduced into the combustion chamber 11, compressed through a compression stroke, and then burned after ignition of the spark plug 16.

However, in the conventional gasoline engine, the fuel injected into the intake port 14 adheres to the inner wall of the intake port 14, and thus, the desired amount of fuel cannot be introduced, and the intake valve 15 is closed after the intake stroke. When the spent fuel is introduced into the combustion chamber 11 only when the next intake stroke starts, a delay in the inflow of fuel occurs (Time Delay), and during incipient operation such as idling when operating at theoretical performance ratio Due to the closing of the throttle valve, inflow into the combustion chamber 11 is blocked and negative pressure is generated in the combustion chamber 11, so that resistance between the piston 17 and the inner wall of the cylinder 18 is generated in the downward motion of the piston 17. As a result, the engine efficiency dropped by about 30%.

In addition, the injector 15 increases the compression ratio for compressing a mixture of air and fuel introduced into the combustion chamber 11 in the conventional gasoline engine mounted on the intake coat 14 side of the intake manifold 13. There were limitations.

[Purpose of invention]

Accordingly, the present invention has been invented to solve the above problems, by adjusting the injection timing and injection time of the fuel at the low and high load of the engine to improve the fuel efficiency by lean combustion and to operate the theoretical fuel ratio It is an object of the present invention to provide a direct gasoline engine for automobiles having squash pistons, which makes it possible to improve engine output and reduce emissions.

[Configuration of Invention]

The present invention for achieving the above object, the cylinder head (4) having a combustion chamber (7) equipped with intake / exhaust valves (1, 2) and spark plugs (3), up and down in the cylinder (5) In the configuration of the lifting piston (6); The combustion chamber 7 of the cylinder head 4 is formed in the shape of a substantially triangular roof, and the piston 6 is divided in its upper part and a part of the piston 6b protrudes, and is recessed stepwise to the protrusion 6b. It has a fine concave surface 6a in the form, and is configured to be mounted to the cylinder head 4 so that the injector 8 for injecting fuel is directed between the intake / exhaust valves 1 and 2 which are upper edges in the combustion chamber 7. It is.

EXAMPLE

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1a, b, c are schematic cross-sectional views, side cross-sectional views and plan views thereof of a direct gasoline engine having a squash piston in accordance with the present invention;

As shown in the drawing, the intake / exhaust valve (1) (2) and the spark plug (3) are mounted on the upper side of the combustion chamber (7) formed by the upper part of the cylinder block and the cylinder head (4). .

An injector 8 for supplying fuel to the combustion chamber 7 is provided on the intake port side of the intake manifold, and the injection of fuel through the injector is performed while the intake valve 1 is closed during the intake stroke. Fuel is injected into the inlet, and the fuel injected into the intake port flows into the combustion chamber in accordance with the opening of the intake valve 1 during the next intake stroke, is compressed through a compression stroke, and then ignition of the ignition plug 3. Combustion is carried out like a normal gasoline engine.

On the other hand, in the present invention, the cylinder head 4 equipped with the intake / exhaust valves 1 and 2 and the spark plug 3 and the combustion chamber 7 formed by the upper part of the piston 6 in the cylinder 5 are provided. A concave surface in which the piston 6 is formed of a roughly trigonal roof, which is referred to as a so-called squash piston, that is, a convex protrusion 6b with a part of which is convex, protrudes in a stepped state. Each of 6a is provided separately.

The injector 8 for injecting fuel is mounted on the cylinder head 4 so as to face the intake / exhaust valves 1 and 2 which are upper edges in the combustion chamber 7.

In addition, the injector 8 is configured to directly inject fuel into the combustion chamber 7 during the compression stroke of the piston 6 as shown in FIG. 2A when the engine is under low load. At the time, as shown in FIG. 2B, during the intake stroke of the piston 6, the piston 6 directly injects fuel into the combustion chamber 7 during the downstroke.

On the other hand, as shown in FIG. 3 showing the injection timing and the use time according to the engine load, the injection timing of the fuel through the injector 8 as described above, the low fuel injection of the engine (Late Fuel Injection) is the piston (6) is variable depending on the engine load in the interval between the bottom dead center of the intake stroke and the top dead center of the compression stroke of the piston 6 from the time after the bottom dead center of the intake stroke in the cylinder (5). When the engine is bent, the injection (Early Fuel Injection) is the compression of the piston 6 from the time after the piston 6 is closed after the top dead center of the intake stroke in the cylinder 5 and the exhaust valve 2 is closed. It is variable depending on the engine load in the section until the top dead center of the stroke.

Here, the injection amount of fuel through the injector 8 is adjusted to satisfy the air-fuel ratio as shown in FIG. 4 of the city line showing that the injection of the fuel according to each engine condition is made for each air-fuel ratio in consideration of the engine load and the rotation speed. do.

In addition, the start timing of the early fuel injection of the engine is the piston when the fuel 6 injected through the injector 8 moves downward during the intake stroke of the engine as shown in FIG. It is determined at a point in time so as to avoid quenching with the upper surface of (6).

Hereinafter, low fuel injection and early fuel injection in an automotive direct gasoline engine having a squash piston of the present invention will be described as follows.

First, the low fuel injection of the engine is performed according to the engine load during the compression stroke in which the piston 6 is after the bottom dead center of the intake stroke in the cylinder 5 and after the intake valve 1 is closed. The start point is variably adjusted and fixed to a point before the top dead center of the end time compression stroke, wherein the flow of fuel injected through the injector 8 is induced by the stepped portion of the raised piston 6 to ignite. When the fuel is injected through the injector 8, the upper concave surface 6a of the piston 6 is allowed to lean around the plug 3 to cover the stratification of the fuel. It is possible to direct the flow of fuel around the spark plug 3 so that it does not enter the crevice between the cylinder 5 and the piston 6.

Therefore, it reduces the hydrocarbon (HC), which is one of the harmful components introduced into the crevice and discharged in the exhaust gas.

In addition, as shown in FIG. 6 showing the pumping loss according to the leanness of the engine, the pumping loss was reduced by approximately 25% or more than when the engine was operated at the theoretical performance ratio, and the pumping loss was introduced into the combustion chamber 7. As the amount of nitrogen and oxygen increases and the specific heat ratio increases, fuel is directly injected through the injector 8 installed directly in the combustion chamber 7 so that the compression ratio can be increased by lowering the temperature in the combustion chamber 7 due to the heat of vaporization of the fuel. Therefore, the direct gasoline engine having the squash piston of the present invention can exhibit an increased theoretical thermal efficiency. [Reference: Theoretical Thermal Efficiency of the Engine = 1- (1 / Compression Ratio) Specific Heat Ratio-1]

In addition, the early FJel injection of the engine is started while the piston 6 moves downward in the intake stroke of the cylinder 5, and the end point is variably adjusted according to the engine load. The fuel injected through (8) is firstly formed in the suction flow through the intake valve (1) to facilitate fine granulation, and is well mixed with the intake and concave surface during the compression stroke, which is the upward movement of the piston (6). Squash flow by (6a) is induced to increase the combustion speed, thereby reducing the generation of exhaust gas due to complete combustion and improving the output of the engine.

[Effects of the Invention]

As described above, according to the present invention, a direct gasoline engine for automobiles having squash pistons, when driving at theoretical performance ratio, the injection of fuel is made by the injector 8 mounted in the combustion chamber 7, and the combustion chamber during vaporization of the injected fuel ( 7) is cooled to improve the filling efficiency of the intake air, the combustion temperature is also lowered, knocking is suppressed.

In addition, since the compression ratio is increased, the engine output is improved by 10% or more, while the fuel in the combustion chamber 7 is directly injected to allow the operation to the theoretical performance ratio at the time of cooling, thereby reducing the generation of carbon monoxide. Since the fuel does not come into contact with the port wall, a precise air-fuel ratio is possible, thereby reducing hydrocarbon emissions, and the fuel injected from the injector 8 is completely burned in the combustion chamber 7 and converted into output, thereby improving the response of the engine and driving performance. There is an advantage that can be improved.

Claims (1)

A cylinder head (4) equipped with intake / exhaust valves (1, 2) and spark plugs (3), having a combustion chamber (7), and a piston (6) which moves up and down in the cylinder (5); The combustion chamber 7 of the cylinder head 4 is formed in the shape of a substantially triangular roof, and the piston 6 is divided in its upper part and a part of the piston 6b protrudes, and is recessed stepwise to the protrusion 6b. It has a fine concave surface 6a in the form and is mounted to the cylinder head 4 so that the injector 8 for injecting fuel is directed between the intake / exhaust valves 1 and 2, which are upper edges in the combustion chamber 7. Automotive direct gasoline engine with squash pistons.