KR100303979B1 - 3-valve gasoline engine - Google Patents

Abstract

The present invention relates to a three-valve direct gasoline engine, and an object thereof is to provide a three-valve direct gasoline engine to efficiently realize ultra-thin combustion when fuel is injected into a combustion chamber. The present invention to achieve the above object

A three-valve direct gasoline engine consisting of two intake ports each provided with an intake valve and one exhaust port provided with an exhaust valve, wherein one of the two intake ports generates a forward tumble and the other uses an intake control valve. The center line passing between the two intake valves and the center line passing between the intake valve and the exhaust valve are respectively referred to as the first center line and the second center line. The injector and the ignition plug are installed in a position opposite to the exhaust valve with respect to the first center line and opposite to the intake valve with respect to the second center line, and have excellent fuel saving effect due to ultra-thin combustion. This has the effect of being improved.

Description

3-valve direct gasoline engine

The present invention relates to a three-valve direct gasoline engine, and more particularly, to optimize the positions of the valves, injectors, and spark plugs employed in the three-valve combustion chamber, thereby increasing fuel saving effects due to ultra-lean combustion, as well as output efficiency. The three-valve direct gasoline engine can be improved.

In general, not only gasoline engines, but also all engines, our goal is to reduce operating costs and reduce harmful emissions while achieving maximum output at the same maximum displacement.

The technology for realizing ultra-lean combustion for the purpose of reducing fuel in small and light vehicles is a method of injecting fuel from the intake port and pursuing lean combustion by appropriate flow in the cylinder, and directly in-cylinder and proper in-cylinder flow. There is a way to seek lean burning by stratifying the mixer (forming a partially rich mixer).

First, in the intake port injection type gasoline engine, the method of homogenizing the atomized fuel as much as possible and rapidly burning it with a strong flow in the cylinder is mainly used. However, the limit of lean burn is narrow and the intake port is designed to generate a strong flow. Significant reduction has limited use in small and light engines. In the intake port injection type gasoline engine, the fuel injector is mounted in the intake pipe or the cylinder head to inject fuel into the intake port. At this time, the injected fuel is generally introduced into the combustion chamber during the intake stroke, and the fuel and air in the combustion chamber are in the form of a uniform mixer during ignition. The intake port of the intake port injection type gasoline engine is required to be designed in consideration of the intake flow rate, tumble flow and swirl flow of the mixer. The lean burn intake port injection type gasoline engine is similar to the general intake port injection type gasoline engine, but the intake flow swirl (horizontal rotational flow, swirl) and tumble (vertical rotational flow, tumble) are used to secure combustion stability at lean fuel consumption. Enhances the properties of the inducer to induce uniform distribution or stratification of the mixer. These engines are divided into a combustion control mode into a region in which lean combustion is applied (fuel mode) and a region in which general combustion is applied (output mode), and the fuel injection method and injection timing in each combustion mode are the same.

The direct injection gasoline engine (G.D.I Engine) is a method of directly injecting fuel into the combustion chamber and pursuing lean combustion through stratification of the mixer by appropriate in-cylinder flow. Recently, the development of high pressure injector technology and the need for improvement of fuel economy have begun to be developed. These direct injection engines have applied a combustion system capable of ultra-thin operation of about 40: 1 for partial load operation, thereby improving fuel efficiency. Bring. Looking at the configuration, a fuel injector driven at high pressure is mounted to the cylinder head, and fuel is injected directly into the combustion chamber. The combustion mode of the direct injection gasoline engine is divided into the fuel efficiency mode, which is an ultra-lean fuel economy operation section, and the output mode, which is a general operation section, and each mode is classified by the fuel injection timing and the flow phenomenon of the mixer. The fuel economy mode enables ultra-thin combustion through stratification of the mixer (making the fuel richer around the ignition plug) and the injection timing of the fuel takes place during the compression stroke to maximize the mixer stratification effect. In the case of the output mode, the same as the intake port injection method except for direct injection of fuel, injection is performed during the intake stroke and a uniform mixer is used. The direct injection gasoline engine has an upright invertible tumble intake port, a spiral intake port with a swirl control valve, etc. for proper stratification and fuel injection timing of the mixer, and a piston top design suitable for each intake port shape. Control the flow of the mixer.

1 is a perspective view of a conventional three-valve lean burn engine related to a light vehicle engine shown in US Patent 5417190. As shown in Fig. 1, lean combustion is achieved by using laminar flow due to tumble flow in the cylinder 2. The cross-sectional shape of the intake port 4 is made into an inverted triangle to reinforce the tumble in the cylinder 2 and to inject fuel from only one intake port 4 of the two intake ports. The spark plug 6 is mounted in a direction opposite to the intake port 4 through which the fuel is injected, so that the ignition of the stratified mixer is advantageous. In addition, a strong tumble is formed in the cylinder 2 until the end of the compression stroke so that the shape of the upper side of the piston 8 favors the shape and integrity of the tubule, so that the stratification of the mixer is preserved.

And FIG. 2 is a longitudinal sectional view of a conventional direct gasoline engine shown in US Patent 5727520. As shown in FIG. 2, an intake port 10 for generating a forward tumble, an injector 12 for injecting fuel at the center of the cylinder, a piston 14 for holding a forward tumble and guiding the sprayed fuel in the spark plug direction. ) And the spark plug 16 located between the upper portions of the intake ports 10. When a strong forward tumble is introduced from the intake port 10, the fuel is injected from the injector 12 located in the center of the cylinder, and the injected fuel is loaded on the forward tumble in the cylinder and guided to the upper shape of the piston to near the spark plug 16. Passed by. At this time, the spark is splashed from the ignition plug 16, so that ignition is made and lean combustion is possible due to laminar flow even when less fuel is injected.

However, in the conventional gasoline engine of FIG. 1, since the fuel is injected from the intake port, the fuel injector must inject the fuel only in the section in which the intake valve is opened. Accordingly, when the injected fuel is introduced into the cylinder through the valve, the intake valve and the valve There is a limit to stratification of fuel injected by rapid flow or turbulence between sheets. Therefore, the limit of lean combustion is narrower than that of a gasoline direct injection engine, and the fuel reduction effect is less.

In addition, in the direct gasoline engine of FIG. 2, in the case of an engine injecting fuel directly into a cylinder, an intake air generating a forward tumble widely used in a general engine without using a unique intake port in order to generate an appropriate flow in the cylinder. Although the port is used, but two intake valves and two exhaust valves are used, the engine has a small combustion chamber, so the spark plug and the injector can be mounted at the center of the cylinder at the same time. Is directly related to the decrease. In addition, since the injector is mounted at the center, the fuel injection target point is near the center of the cylinder, so it is difficult to use the flow generated by the injection pressure of the injector under low engine speed conditions in which the flow in the cylinder is relatively weak. In addition, in the conventional direct injection engine, an injector on the side of the combustion chamber and a spark plug in the center do not need to reduce the size of the valve. However, the injection position and the angle of the injector are limited. There is a problem in that some are buried in the wall of the cylinder to increase the emission of unburned hydrocarbons.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide a three-valve direct gasoline engine that enables ultra-lean combustion to be efficiently realized when fuel is injected into a combustion chamber.

1 is a perspective view showing a conventional three-valve lean burn engine.

Figure 2 is a longitudinal sectional view showing a conventional direct gasoline engine.

3 is a longitudinal sectional view showing a three-valve direct gasoline engine according to the present invention;

4 is a plan view of the combustion chamber of the present invention;

5 is a plan view showing a fuel injection point of the present invention.

Figure 6 is a perspective view showing the flow of the mixer of the present invention.

** Description of symbols for the main parts of the drawing **

110: intake port 112, 114: intake valve

120: exhaust port 122: exhaust valve

130: control valve 140: injector

150: ignition plug 160: piston

200: first center line 300: second center line

In order to achieve the above object, in the present invention, to optimize the position of the valve, injector, spark plug in the combustion chamber to maximize the effect of reducing the fuel, each of the two intake port and the exhaust valve is provided with an intake valve 1 A three-valve direct gasoline engine consisting of two exhaust ports, wherein one of the two intake ports generates a forward tumble and the other is installed to generate swirl flow using an intake control valve, looking upward from the combustion chamber. The injector and the spark plug may be opposed to the exhaust valve on the basis of the first center line passing between the two intake valves, and opposite to the intake valve on the basis of the second center line passing between the intake valve and the exhaust valve. It is done by installation.

In the above-described configuration, the upper surface of the piston upper surface of the lower side of the exhaust valve side is recessed toward the exhaust valve side around the second center line, and the piston upper surface of the lower side of the intake valve side is the head surface of the intake valve. It is characterized by being formed with the same slope as.

Further, in the above-described configuration, a fuel injection point is formed at a position between the intake valve and the injector.

Hereinafter, a three-valve direct gasoline engine according to a preferred embodiment of the present invention will be described in detail.

Figure 3 is a longitudinal sectional view showing a three-valve direct gasoline engine according to the present invention, Figure 4 is a plan view showing a combustion chamber in the present invention, Figure 5 is a plan view showing a fuel injection point of the present invention, Figure 6 is a perspective view showing the flow of the mixer in the present invention.

3 to 6, in the three-valve direct gasoline engine of the present invention, two intake ports 110 are provided with intake valves 112 and 114, respectively, and an exhaust port 120 is provided. One exhaust valve 122 is provided. And, looking down the combustion chamber 100 from above, the center line passing between the intake valves 112 and 114 and the center line passing between the intake valves 112 and 114 and the exhaust valve 122 are respectively first. When referred to as the center line 200 and the second center line 300, the intake port 110 is provided with a control valve 130 to cause the forward tumble and swirl flow, and the first center line 200 The injector 140 and the spark plug 150 are installed at a position opposite to the exhaust valve 122 and opposed to the intake valve 112 around the second center line 300 as a reference.

Here, looking at the ball shape of the upper surface of the piston 160, first, the upper surface of the piston 160, the lower side of the exhaust valve 122 side around the second center line 300 is formed toward the exhaust valve 122 side The piston 160 ball shape below the intake valves 112 and 114 is formed at the same inclination as the head surface of the intake valves 112 and 114 as viewed from the side.

In addition, in the present invention, as shown in FIG. 5, a fuel injection point is formed at a position between the intake valve 112 and the injector 140.

Referring to the operation of the three-valve direct gasoline engine according to the present invention configured as described above are as follows.

First, as shown in FIGS. 3 to 6, the present invention provides a case in which a forward strong tumble is generated in the intake port 110 and a case in which the forward tumble and swirl flow exist simultaneously by closing the intake control valve 130. You can think of it in a separate way. First, when the forward tumble is generated, the fuel is injected from the injector 140 located on the exhaust valve 122 to the upper surface of the recessed piston 160 at a suitable time of the piston compression stroke according to the engine speed and the load. At this time, the target point of the fuel injected is region A of the piston 160, as shown in FIG. The fuel injected into this region moves to region B of FIG. 6 along the upwardly directed piston 160, forming a curved surface with a forward tumble flowing strongly inside the cylinder while mixing with air as in FIG. Since there is a strong forward tumble inside the cylinder, the mixer is moved vertically obliquely along the spray direction by the flow generated when spraying the high pressure injector 140 in the horizontal direction, and the mixer 160 moves upward in the vertical direction. The mixer is moved near the spark plug 150 by the vertical flow generated by the forward tumble flow and the upward movement of the piston 160 because the force is added upward. In the apparatus according to the present invention, when the forward tumble 170 and the swirl flow 171 exist together in the cylinder by the intake control valve 130, the target point of the fuel injected in FIG. 5 becomes A ', and the injection is performed in this region. The fuel is mixed with air and moves vertically along the inclined curved piston shape (ball) by the forward tumble inside the cylinder and is horizontally along the edge of the piston ball by a swirl flow simultaneously in the cylinder. At the moment of ignition, it moves near the spark plug. Air and fuel are mixed so that ignition occurs easily while the mixer moves to the spark plug 150, and the flame is splashed in the spark plug 150 at the optimum time to combust the combustion. The combustion here is combustion during ultra-lean fuel injection. When the load of the engine is large and rapid, fuel is injected in a section where the intake valve 112 is opened to homogenize the mixer. In general, when only the forward tumble is present, the piston ball is made small to achieve stratification.

Although the present invention has been described with reference to the preferred embodiments shown in the drawings, which are merely exemplary, and those skilled in the art may make various modifications therefrom and other embodiments in the equivalent range.

As described above, the present invention is excellent in fuel saving effect due to ultra-thin combustion and has the effect of overcoming the shortage of power that may occur in an engine having a small displacement.

In addition, in the present invention, the problem of securing the mounting position and the mounting angle of the injector, which may occur when the conventional direct type engine is applied to a small combustion chamber, may be sufficiently overcome by using only one exhaust valve.

In addition, since the existing intake port is used, it is possible to flexibly cope with the design and manufacture.

Claims (3)

A three-valve direct gasoline engine consisting of two intake ports each provided with an intake valve and one exhaust port provided with an exhaust valve, wherein one of the two intake ports causes a forward tumble and the other controls intake. It is installed to cause swirl flow by using a valve, and the center line passing between the two intake valves and the center line passing between the intake valves and the exhaust valves, respectively, are viewed from above and above the combustion chamber. When referred to as the second center line, the injector and the spark plug are provided at a position opposite to the exhaust valve with respect to the first center line and opposite to the intake valve with respect to the second center line. Direct gasoline engine. The ball shape of the piston upper surface of the lower side of the exhaust valve side around the second center line is recessed toward the exhaust valve side, and the piston upper surface shape of the lower side of the intake valve side is the head of the intake valve. Three-valve direct gasoline engine, characterized in that formed on the same slope as the surface. The three-valve direct gasoline engine according to claim 1 or 2, wherein a fuel injection point is formed at a position between the intake valve and the injector.