JPS6041209B2 - Combustion chamber of internal combustion engine - Google Patents

Description

[Detailed description of the invention] The present invention relates to a combustion chamber of an internal combustion engine.

Hydrocarbons (H) contained in the exhaust gas emitted from internal combustion engines
C), carbon monoxide (CO) and nitrogen oxides (N○x)
Internal combustion engines are required to reduce the amount of harmful components such as carbon dioxide, etc. and to improve their thermal efficiency, and meeting these requirements has become an important issue.

As a method to efficiently reduce harmful components in exhaust gas, the above three components (HC, CO and N○x) are reduced using a lean mixture.
There are known methods for simultaneously reducing N○× and methods for reducing N○× by recirculating a large amount of exhaust gas into the engine intake system.

However, these lean mixtures and mixtures containing a large amount of recirculated exhaust gas have slow flame propagation speeds, slow combustion speeds, and cannot achieve sufficiently high thermal efficiency. As a result, the disadvantage is that the output is unsatisfactory. Therefore, when using such a combustible mixture, increasing the combustion rate is the most important issue in increasing thermal efficiency. As a combustion chamber structure for accelerating the combustion speed of the combustible mixture in the combustion chamber, the present inventor has developed an on-off valve that opens and closes in time with the crankshaft of an internal heat engine, from at least the vicinity of the start of the compression stroke to the vicinity of the end of the compression stroke. The storage chamber is connected to the combustion chamber through the opening/closing valve, and the high-pressure combustible mixture in the combustion chamber at the end of the compression stroke is stored in the storage chamber during the vertical stroke of the next cycle. An internal combustion engine has already been proposed in which the high-pressure combustible air-fuel mixture stored in the previous cycle is injected into the combustion chamber at the start of the cycle to generate a swirling flow or turbulence in the air-fuel mixture in the combustion chamber to increase the combustion speed.

(Refer to Special Publication No. 7 of 1983). The present invention further improves the above-mentioned invention, and includes forming a squish area between the inner wall surface of the cylinder head and the top surface of the piston. This improves combustion both with the air mixture flow. Embodiments of the present invention will be described below with reference to the drawings.

Fig. 1 is a cross-sectional front view of the first embodiment of the present invention, and Fig. 2 is a cross-sectional front view of the first embodiment of the present invention.
It is a view taken along the low D arrow in the figure. Referring to Figures 1 and 2, 1 is a cylinder block, 3 is a cylinder head, 5 is a combustion chamber, and 7 is a piston.The combustion chamber 5 is opened and closed in time with the crankshaft (not shown). Intake valve 1
1 (FIG. 2) to an intake boat (not shown), and the intake boat is passed through a fuel supply device such as a carburetor (not shown) to place the nuclear intake valve 11 on the valve seat 13. They work together to control the supply of combustible mixture from the intake boat to the combustion chamber 5. The term combustible mixture also includes lean mixtures or mixtures containing recirculated exhaust gas. Combustion chamber 5 with exhaust valve 17
The lotus is passed through to the exhaust boat 15 through. The valve rod 19 fixed to the exhaust valve 17 protrudes from the cylinder head 3, and the valve rod 19 is pulled out by the compression spring 21 attached to the cylinder head 3.
The exhaust valve 17 is urged upward to cause the exhaust valve 17 to collide with the valve seat 23, and the valve is operated by a valve engagement mechanism 25 which operates when the crankshaft (not shown) is activated. Activate the head 19 to open the exhaust valve 1.
Controls the opening and closing of 7. The ignition plug 27 is screwed onto the wall of the combustion chamber 5. 27a is an electrode of the spark plug 27. A mounting hole 31 for an on-off valve 37 is bored in the cylinder head 3, and a valve member 33 is tightly fitted into the mounting hole 31.

A hole 33a in the axial direction is bored in the valve member 33, and a valve rod 35 is slidably fitted in the hole 33a in a sealing manner. An on-off valve 37 is fixed to the tip of the valve rod 35 so as to cooperate with a valve boat 33b formed on the valve member 33. That is, the upper end of the valve rod 35 is urged upward by the compression spring 39, and the valve boat 33b is normally closed by the on-off valve 37. Furthermore, a valve mechanism 4 is operated by synchronizing the upper end of the valve rod 35 with a crankshaft (not shown).
1 to open and close the valve 3 at the timing described later.
Controls the opening and closing of 7. One end 43a closes above the on-off valve 37, the other end 43b connects to the outer wall of the cylinder head 3, and the space between both ends 43a and 43b is key molded or machined into the cylinder head 3 to form a uniform circular or rectangular shape. They are communicated through a long hole 43 having a cross section of .

The outlet end of the elongated hole 43 is fitted into an air storage chamber 45 having a predetermined volume.
Thus, the largest hole 43 and the storage chamber 45 form a storage chamber 47 having a reciprocating flow. Storage chamber 47 and combustion chamber 5
A cup 49 is attached to an outer position of the on-off valve 37 between the opening and closing valve 37. A plurality of nozzles are bored on the surface of the cup 49, and the on-off valve 3
The combustible air-fuel mixture stored in the storage chamber can be jetted into the combustion chamber 5 from the counterfeit opening by the valve 7. Here, it is preferable that one of the counterfeit holes is formed to generate a jet flow that bridges the electrode 27a of the spark plug 27 to improve ignitability. Further, it is preferable that the other counterfeit holes are formed so as to generate a unidirectional swirling flow or a unidirectional jet flow that generates uniform turbulence in the combustion chamber 5. A squish area is formed between the cylinder head inner wall surface 3a located on the opposite side of the warm circle of the cup 49 with respect to the cylinder axis and the top surface peripheral portion 7a of the piston 7. The counterfeit part is placed on an extension of the central part of this Schitshuaria. A second embodiment of the present invention will be described with reference to FIG.
Since the second embodiment is the same as the first embodiment except for the structure of the storage chamber, the same parts are given the same numbers and their explanation will be omitted. In FIG. 3, the storage chamber 47' is the shilling head 3.
The hole 43' is formed by key molding or machining and has a rectangular or circular cross section that is uniform in the longitudinal direction. Most hole 4
One end 43'a of 3' is closed above the on-off valve 37, and the pond end 43'b is closed to the outer wall of the cylinder head 3, and the end 43'b is closed to the outer wall of the cylinder head 3.
A blind cypress 48 is screwed to 'b. As another embodiment (not shown) of the present invention, a storage chamber may be provided in the vicinity of the exhaust boat to enable heat exchange, and the intake air in the storage chamber may be heated by the heat of the exhaust boat.

In this case, the structure of the storage chamber may be changed to the first embodiment or the second embodiment.
The structure may be similar to that of the embodiment. The operation of the first and second embodiments of the present invention will be explained below with reference to the opening/closing timing chart of the intake valve, exhaust valve, and on-off valve of FIG. 4.

In Fig. 4, the engine axis represents the crankshaft rotation angle 8, the vertical axis represents the valve height, the valve height of the intake valve 11 is indicated by a two-dot chain line 1, the valve height of the exhaust valve is indicated by a broken line E, and The valve height of the on-off valve is shown by a solid line S. Just before the top dead center (TDC) shown on the left, the intake valve 11 engages, enters the intake stroke, and when the engine passes the top dead center, the exhaust valve closes and the combustible air-fuel mixture is sucked into the combustion chamber 5.

When the engine passes the bottom dead center (BDC) and enters the compression stroke, the intake valve 11 closes, and immediately after that, the on-off valve 37 opens. A storage chamber 47 or 47 separated from the combustion chamber 5 by an on-off valve 37
As will be described later, a high-pressure combustible air-fuel mixture is stored at the end of the compression stroke of the previous cycle, and the pressure of the air-fuel mixture is sufficiently higher than the pressure in the combustion chamber 5 at the time the on-off valve is opened. Therefore, when the on-off valve 37 is opened, the storage chamber 47 or 47
The high-pressure air-fuel mixture in ' is ejected from the lamp of the cup 49 and generates a swirling flow or turbulence in the combustion chamber 5. By making the cross-sectional area of the warm square of the cup 49 smaller than the cross-sectional head of the elongated hole 43 or 43' of the storage chamber 47 or 47', the strength of the jet from the jet square can be increased. When the piston 7 further rises and the pressure within the combustion chamber 5 increases, the combustible air-fuel mixture within the combustion chamber 5 flows to the opening of the cup 49 and the valve boat 33b.
into the storage chambers 47, 47'.

Next, the on-off valve 37 closes before the top dead center, when the ignition timing is close to the most advanced ignition timing, and when the flame ignited by the ignition plug 27 does not enter into the storage chambers 47, 47'.
That is, when the ignition flame enters the storage chambers 47, 47', the combustible air-fuel mixture in the storage chambers 47, 47' is combusted.
However, when the combustible air-fuel mixture stored in the storage chambers 47, 47' is combusted in this way, this combustion gas cannot be used to push down the piston 7, and thus fuel is wasted. become. Therefore, in the present invention, the on-off valve 37 is opened as late as possible before the ignition flame from the ignition plug 27 enters the storage chambers 47, 47', that is, near the most advanced ignition timing. When the on-off valve 37 is closed, the high pressure air-fuel mixture is stored in the storage chambers 47, 47'. Next, when the piston 7 further rises, a squish flow V is generated, and this squish flow V causes turbulence throughout the combustion chamber 5. At the same time, the squish flow flowing out from the middle reaction part of the squish cheria passes through the rear opening of the cup 49 to the cup 49. 49, and the cup 49
This causes turbulence to the air-fuel mixture inside.

In the combustion chamber 5, turbulence generated by the jet flow from the storage chambers 47, 47' at the beginning of the compression stroke remains until the end of the compression stroke, and turbulence is also generated by the squish flow at the top of the piston 7. be done.

In this state, the electrode 27 of the spark plug 27 reaches the point indicated by the arrow lc.
Sparks are emitted from a, the turbulent compressed mixture is combusted, and the mixture enters the expansion stage. The above-mentioned turbulence within the combustion chamber 5 accelerates the combustion rate and improves thermal efficiency. Furthermore, since the air-fuel mixture in the cup 49 is also turbulent due to the squish flow, the flame propagates into the cup 49 through the squirt opening, and the air-fuel mixture in the cup 49
The air-fuel mixture inside can also be combusted well. In this way, the entire air-fuel mixture within the combustion chamber 5 can be burnt satisfactorily.
Just before bottom dead center (BCD), the exhaust valve 17 is engaged to discharge exhaust gas from the exhaust boat 15 to the exhaust manifold.
The following operations of the aircraft are repeated. In the first and second embodiments, the holes 43, 4 in the storage chambers 47, 47' are
3', and in the first embodiment, due to the difference in cross-sectional area between the first hole 43 and the air storage chamber 45, the second
In the embodiment, due to the propagation of pressure fluctuations in the closed area formed by the long holes 43', when the high pressure mixture flows into the closest holes 43, 43' and the stored high pressure mixture flows out from the long holes 43, 43'. The mixture flows violently.

Due to the mechanical vibration effect caused by the flow of the air-fuel mixture, the air-fuel mixture is mixed and the fuel particles contained in the air-fuel mixture are atomized (atomized), and the surface area of the fuel particles is expanded due to the atomization of the fuel particles, and the flow reduces the size of the fuel particles. It is moved to a fresh air region of vapor pressure to promote vaporization. By injecting the stored air-fuel mixture that has been sufficiently mixed, atomized, and vaporized into the combustion chamber 5, the ignitability is further improved and the combustion speed is further increased. Further, by heating the storage chamber with the heat of the exhaust boat as in an embodiment not shown, conversion and vaporization can be similarly promoted, and the mixture pressure in the storage chamber can be increased by heating.

As a result, the effect of improving the combustion rate due to the ejection of the stored air-fuel mixture is enhanced, and the thermal efficiency is improved. This effect is particularly noticeable when the engine is cold. As described above, according to the present invention, since the ignition flame does not enter the storage chamber, the flammable air-fuel mixture stored in the storage chamber can be used to push down the piston. Further, by forming a squish area, it is possible to provide further turbulence in addition to the turbulence caused by the mixture flow jetted from the throat, and thus the combustion speed can be significantly increased. Furthermore, since turbulence is also generated within the cup due to the squish flow, the air-fuel mixture within the cup can be burnt well, and in this way, the air-fuel mixture within the entire combustion chamber can be burnt well.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional front view of the first embodiment of the present invention, and Fig. 2 is a cross-sectional front view of the first embodiment of the present invention.
3 is a sectional front view of the second embodiment of the present invention, and FIG. 4 is the intake valve of the first embodiment or the second embodiment,
FIG. 3 is an operation diagram of an exhaust valve and an on-off valve. 1...Cylinder block, 3...Cylinder head, 5...
Combustion chamber, 11... Intake valve, 15... Exhaust boat, 17... Exhaust valve, 27... Spark plug, 37
...Opening/closing valve, 43, 43'...most hole (reciprocating flow path)
, 45...Air storage chamber, 47, 47'...Storage chamber, 48...Blug. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. A valve port in which a combustible mixture storage chamber for temporarily storing a part of the combustible mixture introduced into the combustion chamber from the engine intake system is formed in the cylinder head, and the storage chamber is formed in the storage chamber. An on-off valve that is connected to the combustion chamber through a valve and driven by an engine-driven valve drive cam is provided at the valve port, and the on-off valve controls the opening and closing of the valve port, and the on-off valve is opened and closed immediately after the intake valve closes. The valve is opened over the range of crank angles until the compression stroke is started or before top dead center, the ignition timing is close to the most advanced ignition timing, and the ignition flame from the ignition plug does not enter the storage chamber. In an internal combustion engine, the high-pressure combustible mixture stored in the storage chamber in the previous cycle is injected into the combustion chamber during the first half of the compression stroke. A nozzle is formed, a squish area is formed between the inner wall surface of the cylinder head located on the opposite side of the nozzle with respect to the cylinder axis, and the top surface of the piston, and the nozzle is disposed on an extension of the center of the squish area. Combustion chamber of an internal combustion engine.