JPH0754656A - Engine combustion chamber - Google Patents

Abstract

PURPOSE:To make combustion mixture reach the inner most part of a main combustion chamber as the result of accelerating its velocity so as to shorten a burning time, by providing a sub-combustion chamber from whose injection nozzle supplied fuel is injected into a cylinder, a control valve to open and close the injection nozzle, and a means to limit effective area with a control valve 'open' in the initial stage when process of control valve opening action begins. CONSTITUTION:A sub-combustion chamber 31 on whose bottom an injection nozzle 32 is formed, is provided in a cylinder head 3. A control valve 4 to control open-close of the injection nozzle 32 touches closely from below to a valve seat 33 provided below this injection nozzle 32, and closes the sub-combustion chamber 31. In the control valve 4, a flow rate regulating unit 47 is formed between a head 46 and a stem 43. When this control valve 4 is closed, a gap is formed between the flow rate regulating unit 47 and a side wall of the valve seat 33 opposite thereto. Consequently, the valve opening effective area of the control valve 4 is reduced, flow velocity of mixture to be injected into the main combustion chamber 22 is accelerated, this mixture is made to reach the inner most part of the main combustion chamber 22 so as to shorten its burn time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a combustion chamber of an engine, and more particularly to a structure of a combustion chamber of a diesel engine.

[0002]

2. Description of the Related Art Fossil fuels such as gasoline are often used as fuel for internal combustion engines, which are the prime movers of vehicles. High-pressure gas fuel is also partially used as fuel for internal combustion engines. Recently, high-pressure gas fuel has begun to be used as a fuel for diesel engines for power generation equipment in small-scale power generation units such as city buildings. When injected into the combustion chamber of the engine, the gas fuel may be poorly mixed with air and difficult to self-ignite, and the exhaust gas may contain a considerable amount of NOx. Also, it is quite difficult to remove NOx from exhaust gas even in a diesel engine that uses fluid fuel.

[0003]

SUMMARY OF THE INVENTION The present invention is intended to eliminate the above-mentioned conventional inconveniences, and an object thereof is to rapidly mix a main combustion gas in a combustion engine with an auxiliary combustion chamber. It is intended to provide a combustion chamber of an engine which is moved to the chamber and whose combustion is completed in a short time.

[0004]

In order to achieve the above-mentioned object of the present invention, the present invention is provided with a sub-combustion chamber which communicates with the main combustion chamber through an injection hole and is introduced into the sub-combustion chamber. In an engine that ejects a combustion mixture of fuel into the main combustion chamber from the ejection holes, a sub-combustion chamber that is provided in the upper part of the cylinder and ejects the gas fuel supplied inside from the ejection holes into the cylinder, and a sub-combustion chamber A combustion chamber of an engine, comprising: a control valve for opening and closing the injection hole of the control valve; and a flow rate adjusting means for limiting an effective opening area of the control valve at an initial stage of a stroke of an opening operation of the control valve. .

[0005]

[Function] When the fuel introduced into the auxiliary combustion chamber is ignited and the combustion mixture is ejected from the ejection hole of the auxiliary combustion chamber to the main combustion chamber, the effective jet area of the ejection hole is temporarily narrowed to reduce the flow velocity of the combustion mixture. Early, the combustion mixture is allowed to reach the back of the main combustion chamber to shorten the combustion time.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a configuration diagram of a main part showing an embodiment of a combustion chamber of a gas engine according to the present invention, in which 1 is a cylinder. A piston 2 is arranged inside the cylinder 1 so as to be vertically movable. FIG. 1 shows the piston in the uppermost position, and the main combustion chamber 22 is formed on the upper surface of the piston 2. Reference numeral 24 is a piston ring, and 25 is a connecting rod.

A sub-combustion chamber 31 is provided in the cylinder head 3 located at the upper end of the cylinder 1. The sub-combustion chamber 31 is made of, for example, high-strength and heat-resistant ceramics, and an ejection hole 32 is formed at the bottom thereof.

Reference numeral 4 denotes a control valve for controlling the opening and closing of the ejection hole 32, which comes into close contact with the valve seat 33 provided below the ejection hole 32 from below to close the auxiliary combustion chamber 31. The stem 43 of the control valve 4 is the valve guide 3 of the upper wall portion 34 of the auxiliary combustion chamber 31.
5, the stem 43 is biased by a spring 45 that pushes up the upper plate 44. As shown in FIG. 2, the control valve 4 has a flow rate adjusting portion 47 having a diameter larger than the diameter of the stem between the head 46 and the stem 43. Further, when the control valve 4 is closed, a gap 47 is formed between the flow rate adjusting unit 47 and the side wall of the valve seat 33 portion facing the flow rate adjusting unit 47.

Reference numeral 5 denotes a gas fuel valve mounted on the upper side of the auxiliary combustion chamber 31, which controls the gas flow by opening and closing a gas fuel supply port 54 from the gas supply pipe 53 to the auxiliary combustion chamber 31. The valve spring 52 that pushes up the upper end of the stem 51 normally closes the supply port 54. A control valve 55 controls the flow rate of the fuel gas.

Although not shown in FIG. 1, a control valve 4 and a gas fuel valve 5 are provided above the cylinder head 3, respectively.
Is provided with a cam mechanism that opens and closes at a timing described later. The drive mechanism for opening and closing these valves need not be a cam, but may be an electromagnetically driven valve mechanism driven by electromagnetic force.

Although not shown in FIG. 1, the cylinder head 3 is provided with a normal intake hole and an intake valve, an exhaust hole and an exhaust valve, and a cam mechanism for driving these two valves. .

Next, the operation of the embodiment of the present invention will be described with reference to FIGS. The operation is started from the exhaust stroke in which the exhaust valve (not shown in FIG. 1) opens and the piston 4 starts rising from the bottom dead center. In this state, the gas fuel valve 5 is closed and the control valve 4 is open. When the piston 2 rises and the combustion gas in the cylinder 1 is exhausted to the outside of the engine, an exhaust valve not shown in FIG. 1 closes and an intake valve not shown also opens. The control valve 4 remains open. When the piston 2 starts descending from the top dead center, fresh air is sucked into the cylinder 1 through the intake hole. The control valve 4 begins to close during the inhalation. Therefore, the control valve 4
Shifts from the state of FIG. 2 to the state of FIG. Therefore, the flow rate adjusting unit 47 is inserted into the gap 48, and the effective flow area between the main combustion chamber and the auxiliary combustion chamber is narrowed. After that, the state of FIG. 4 is reached and the state of FIG. 5 is reached. In this state, the flow between the main combustion chamber 22 and the sub combustion chamber 31 in the cylinder is cut off, and the engine shifts to the compression stroke. At this time, the gas fuel valve 5 is opened, and the gas fuel is supplied to the auxiliary combustion chamber 31. The supply amount of this gas fuel is adjusted by the control valve 55 depending on the load state of the engine.

When the piston starts rising from the bottom dead center position, the air in the cylinder starts to be compressed. Then, when the piston 2 approaches the top dead center, at this timing, the control valve 4
Is slightly lowered and opened, the air compressed in the cylinder flows into the sub-combustion chamber 31 to generate an air-fuel mixture, and when the temperature in the sub-combustion chamber 31 reaches the ignition point, the sub-combustion chamber 31 In 31, combustion starts in a fuel rich state.

The air-fuel mixture in the auxiliary combustion chamber is ejected from the ejection holes 32 into the main combustion chamber 22, but the control valve 4 is in the state shown in FIG. Therefore, since the flow rate adjusting portion 47 is in the gap 48, the effective valve opening area of the control valve 4 is narrowed, and the main combustion chamber 22
The flow velocity of the air-fuel mixture jetted to the is accelerated, and the air-fuel mixture is jetted far away from the jet holes 32 toward the cylinder side wall, and the air-fuel mixture is generated in the entire main combustion chamber 22 and the combustion also occurs in the main combustion chamber 22. After that, the control valve 4 descends to the position shown in FIG. 2 and is in a fully opened state, the air-fuel mixture is blown out from the auxiliary combustion chamber 31 to the main combustion chamber, and the combustion ends within a short time. The piston 2 is pushed down by this combustion. Piston 2
When the engine passes the bottom dead center, the engine moves to the exhaust stroke of the next cycle. 6 is a time chart explaining the operation of the engine.

FIG. 7 shows another embodiment of the flow rate adjusting portion provided in the control valve 4. In this embodiment, the cross section of the flow rate adjusting portion 47 ′ is formed in a substantially semicircular slit shape. Therefore, when the air-fuel mixture is ejected from the sub-combustion chamber 31 to the main combustion chamber 22, it is as if the air-fuel mixture was ejected from a plurality of nozzles, and the flow velocity of the ejected air-fuel mixture is accelerated. By reaching the side wall of the cylinder of the combustion chamber, combustion can be performed rapidly and in a short time, and the combustion efficiency is also increased.

In the above embodiment, the control valve 4 has only one portion for limiting the clearance area, but in the next embodiment, two portions are provided for limiting the clearance area. Figure 8
Is a partially enlarged view thereof. In FIG. 8, the ejection hole 32 is provided with a gap 48 ′ that is one step deeper than the gap 48 shown in the above embodiment. This gap 48 '
As shown in FIG. 7, the cross section of the lower portion is provided with a plurality of nozzle-shaped flow rate adjusting portions 49. . 8 to 11 are explanatory views for explaining the operation of this embodiment, and FIG. 12 is a time chart of this embodiment. In this example,
The subsequent operation is the same, except that the effective area of the gap changes in two steps.

In the above embodiment, the fuel was gas fuel, but it is needless to say that it can be applied to a liquid fuel engine by changing the gas fuel valve 5 and its associated parts to conventional injection gas for liquid fuel. That's a good thing.

[0018]

As described in detail above, according to the present invention, when the gaseous fuel introduced into the auxiliary combustion chamber is ignited and the combustion mixture is ejected from the ejection holes of the auxiliary combustion chamber to the main combustion chamber at the initial stage. The effective jet area of the ejection hole is temporarily narrowed to accelerate the flow velocity of the combustion mixture, and the combustion mixture is allowed to reach the inside of the main combustion chamber to shorten the combustion time. And, since high pressure, reduction ratio and corn burn are possible, thermal efficiency is improved. In addition, the compression stroke can be reduced by introducing air from the main combustion chamber to the auxiliary combustion chamber in the compression stroke, and the amount of introduced air can be controlled with an arbitrary clearance area, so the control valve can be opened and closed once per engine cycle. The structure is simple. In addition, since a partial opening can be provided when the air-fuel mixture is ejected from the auxiliary combustion chamber to the main combustion chamber, the air-fuel mixture reaches the outer circumference of the cylinder with high kinetic energy and the air in the main combustion chamber And the mixing speed is improved, the combustion speed is improved, and the thermal efficiency is improved.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part showing an embodiment of a combustion chamber of a gas engine according to the present invention.

FIG. 2 is an explanatory diagram illustrating an operation of the embodiment.

FIG. 3 is an explanatory diagram illustrating an operation of the embodiment.

FIG. 4 is an explanatory diagram illustrating an operation of the embodiment.

FIG. 5 is an explanatory diagram illustrating an operation of the embodiment.

FIG. 6 is a time chart explaining the operation of the embodiment.

FIG. 7 is a partial cross-sectional view explaining the operation of another embodiment.

FIG. 8 is an explanatory diagram illustrating an operation of another embodiment.

FIG. 9 is an explanatory diagram illustrating an operation of another embodiment.

FIG. 10 is an explanatory diagram illustrating an operation of another embodiment.

FIG. 11 is an explanatory diagram illustrating an operation of another embodiment.

FIG. 12 is a time chart explaining the operation of another embodiment.

[Explanation of symbols]

 Cylinder 2 Piston 22 Main combustion chamber 24 Piston ring 25 Connecting rod 3 ··· Cylinder head 31 ··· · Sub-combustion chamber 32 ··· · Injection port 33 ··· Valve seat 34 ··· Upper wall 35 ・ ・ Valve guide 4 ・ ・ ・ ・ ・ ・ Control valve 43 ・ ・ ・ ・ ・ ・ Stem 44 ・ ・ ・ ・ Upper plate 45 ・ ・ ・ ・ ・ ・ ・ ・ Spring 46 ・.... Heads 47, 47 '... Flow rate adjusting unit 48 ..... Gap 5 ..... Gas fuel valve 51 ..... Stem 52 ... ··· Stem 53 ··· Gas supply pipe 54 ···· Supply port 55 ··· Control valve

Claims (6)

[Claims] 1. An engine having a sub-combustion chamber communicating with the main combustion chamber through an ejection hole, and ejecting a combustion mixture of fuel introduced into the sub-combustion chamber from the ejection hole to the main combustion chamber And a control valve that opens and closes the ejection hole of the sub-combustion chamber and a sub-combustion chamber that ejects the fuel supplied inside into the cylinder from the ejection port, and controls the opening operation of the control valve at the beginning of the stroke. A combustion chamber of an engine, comprising: a flow rate adjusting unit that limits an effective valve opening area. 2. A control valve for opening and closing the inside of the jet outlet is provided with a fitting portion having an arbitrary gap, and the control valve has a range in which the effective area can be controlled to be substantially constant even when the control valve is in a half-open state. The combustion chamber of the engine according to claim 1, wherein 3. The opening and closing of the injection hole of the control valve has a region having an arbitrary gap with the lift of the control valve and a region that is partially opened and is almost fully opened. The combustion chamber of the engine according to claim 1. 4. The opening and closing of the injection hole of the control valve has a region that is partially opened and a region that is almost fully opened when the control valve is lifted. The combustion chamber of the described engine. 5. The combustion chamber of the engine according to claim 1, wherein the fuel is a gas fuel. 6. The combustion chamber of an engine according to claim 1, wherein the fuel is a fluid fuel.