JPS6041208B2 - 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)
Reduction of harmful components such as heat exchangers and other harmful components and improvement of thermal efficiency of internal combustion engines are two major issues that are required of internal combustion engines.

As a method to efficiently reduce harmful components in exhaust gas, a lean mixture is used to reduce the above three harmful components (HC, CO and N○x).
) and methods to reduce N○× by recirculating a large amount of exhaust gas into the engine intake system are known. However, these lean mixtures and mixtures containing a large amount of recirculated exhaust gas have slow flame propagation speeds and low combustion speeds, so that sufficiently high thermal efficiency cannot be obtained.

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. The following methods are conventionally known for increasing the combustion speed of combustible mixture within a combustion chamber.

A method in which swirling flow is generated in the combustion chamber by the combustible air-fuel mixture taken in from the intake boat, or turbulence is generated by squish flow.

In this method, the swirling flow generated during the intake stroke attenuates by the end of the compression stroke, and although the squish flow causes local turbulence near top dead center, it cannot form turbulence throughout the combustion chamber, promoting combustion. The effect is insufficient.

A method in which air is sucked in by negative pressure inside the cylinder through the auxiliary intake valve during the intake stroke, and this ejected air generates a swirling flow in the combustion chamber.

With this method, when the cylinder internal pressure during the intake stroke is low, such as during high-load operation, the flow velocity of the ejected air becomes extremely slow, making it difficult to generate a swirling flow. By the end of the compression process when it is ignited by the spark plug, it is attenuated and the combustion promotion effect becomes insufficient.

Therefore, with these methods, it is difficult to impart strong turbulence to the combustible mixture that can last during the combustion period and promote combustion.

In view of this problem, the present invention aims to generate almost uniform turbulence throughout the combustion chamber at the beginning of the compression process and to promote combustion within the combustion chamber by the generated turbulence. In an internal combustion engine, a combustion chamber is connected to a storage chamber that temporarily stores a part of the combustible mixture in the combustion chamber via a suff valve that opens and closes near the end of the compression stroke. There is provided a combustion chamber for an internal combustion engine, characterized in that a plurality of counterfeit ports for generating turbulence throughout the combustion chamber are provided at the entrance to the combustion chamber. 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.
FIG. Referring to FIG. 1, 1 is a cylinder block, 3 is a cylinder head, 5 is a combustion chamber, and 7 is a piston. The combustion chamber 5 and the intake port 9, which communicates with the carburetor (not shown), are connected to the crankshaft (not shown), and an intake valve 11 that opens and closes the intake port 9 passes through the combustion chamber 5 and the carburetor (not shown). The supply of the combustible mixture to the combustion chamber 5 is controlled by the intake valve. Here, the combustible mixture refers to a lean mixture, a mixture mixed with recirculated exhaust gas, and the like. In addition, an exhaust boat (not shown) that fits into the combustion chamber 5 and an exhaust pipe (not shown) is connected to the exhaust valve 13 (Fig. 2), which opens and closes in time with the crankshaft (not shown). The exhaust gas from the combustion chamber 5 is controlled by an exhaust valve 13 (FIG. 2). The ignition plug 15 is fixed to the head part of the combustion chamber.
Furthermore, in the present invention, a storage chamber turtle 7 is formed in the cylinder head 3. A valve boat 7a is formed at the lower part of the storage chamber 17, and a sub-valve 9 is provided which cooperates with the valve boat 17a to control the opening and closing of the storage chamber 7. The valve head 21 is fixed to the suffix valve 19, and the rear end 2 of the second valve head 2 protrudes from the cylinder head 3, and the seat 23 is fixed. A pressure spring 25 is installed between the seat 23 and the outer surface of the cylinder head 3, and the sub-valve 1
9 upward to close. On the other hand, the seat 23 is pressed by the valve control cam 27, which operates in response to the crankshaft (not shown), and the sub-valve 19 is opened and closed at timings as will be described later. A cap 29 is attached between the storage chamber 17 and the combustion chamber 5 so as to cover the sub-valve 19 provided at the entrance of the storage chamber 17, and this cap 29 closes the entrance of the valve boat 173 into the combustion chamber 5. cover.

The surface of the cap 29 has a plurality of openings 29a, 29b,
29c and 29d are worn. But Safbalp 1
9, the air-fuel mixture stored in the storage chamber 17 can be injected into the combustion chamber 5 through the openings 29a to 29d (dashed line A), and the injected air-fuel mixture causes turbulence in the combustion chamber 5. (
Generate arrow V). Here, the size and direction of the nozzles 29a to 29d correspond to the air-fuel mixture spouted from the nozzles (arrow A).
The combustion chamber 5 is selected so that substantially uniform turbulence (arrow V) is generated in the entire area within the combustion chamber 5, taking into consideration the space volume reached by the combustion chamber 5. Furthermore, it is preferable to select one of the ejected air-fuel mixtures (arrow A) to scavenge the electrode of the spark plug 15, thereby improving the ignitability. Next, the opening/closing timing of each valve of the device of the present invention will be explained with reference to FIG.

In FIG. 3, the rotation angle 8 of the crankshaft is plotted on the machine axis, and the valve lifts of the intake valve 11, exhaust valve group 3, and sub-valve 19 are plotted on the vertical axis, which are indicated by a chain line 1, a broken line E, and a solid line S, respectively. Immediately before top dead center (TDC), intake valve 1 1 engages, enters the intake stroke, and when it crosses top dead center, exhaust valve 13 closes and combustion chamber 5
A flammable mixture is inhaled into the tank. When the engine passes the bottom dead center (8CD) and enters the compression stroke, the intake valve 11 closes, and immediately after that, the sub-valve 19 engages. As will be described later, in the storage chamber turtle 7, an air-fuel mixture with a pressure higher than the pressure in the combustion chamber at the time of opening of the sub-valve turtle 9 is stored at the end of the compression stroke of the previous cycle.
Therefore, when the sub-valve 19 is opened, the high-pressure air-fuel mixture in the storage chamber 17 is exposed to the false openings 29a, 29b, 29c of the cap 29.
It is ejected from 29d and generates almost uniform turbulence throughout the combustion chamber 5. As the piston 7 continues to rise further and the pressure within the combustion chamber 5 increases, the compressed high-pressure air-fuel mixture within the combustion chamber 5 flows through the ports 29a, 29b, 29c and 29d.
From there, it passes near the sub-valve turtle 9 and enters the storage chamber 17. Next, the sub-valve 19 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 15 does not enter the storage chamber 17. That is, when the ignition flame enters the storage chamber 17, the combustible air-fuel mixture within the storage chamber 17 is combusted. However, by burning the combustible air-fuel mixture stored in the storage chamber 17, the combustion gas cannot be used to push down the piston 7, and thus fuel is wasted. Therefore, in the present invention, the sub valve 19 is opened at the latest possible timing before the ignition flame from the ignition plug 15 enters the storage chamber 17, that is, near the most advanced point VH timing. When the sub-valve 19 opens, the high-pressure air-fuel mixture is stored in the storage chamber 17. Next, at the point indicated by arrow IG, a spark is emitted from the ignition plug 15 to combust the compressed air-fuel mixture in the combustion chamber 5, and the engine enters an expansion stroke. Immediately before bottom dead center, the exhaust valve 13 is activated to discharge the burnt gas in the combustion chamber 5 from the exhaust boat to the exhaust manifold, and the same operation is repeated thereafter. As described above, the device shown in FIGS. 1 and 2 stores the high-pressure intake air-fuel mixture at the end of the compression stroke in the storage chamber, and injects the high-pressure air-fuel mixture from the storage chamber into the combustion chamber at the beginning of the compression stroke of the next cycle. Since uniform turbulence can be generated in the combustion chamber and ignition occurs before the turbulence decays and disappears, extremely good combustion can be obtained.

A second embodiment of the present invention will be described with reference to FIG.

In the device shown in FIG. 4, the mounting position of the spark plug 15 is different from the device in FIG. 1, but the rest is the same as in FIG.
Identical parts will be given the same reference numerals and their explanations will be omitted.
In the case shown in FIG. 4, the ignition plug 15 faces the passage between the valve boat 17a of the storage chamber 17 and the openings 29a to 29d of the cap 29 fixed to the tip of the storage chamber 17. The opening and closing timings of the intake valve 11, exhaust valve and sub-valve 19 are the same as in the device shown in FIG. In the device shown in FIG. 4, when the electrode of the spark plug 15 interacts with the sub-valve 19, the mixture is surely streaked by the air-fuel mixture jetted out from the storage chamber 17, and the jetted air-fuel mixture is filled almost uniformly into the combustion chamber 5. It is ignited after forming a similar turbulence.

At this time, the flame jet flows through each port 29a, 29b, 29c, 2
Since it is ejected from 9d, combustion is better. A third embodiment of the present invention is shown in FIGS. 5 and 6.

This device is similar to the device shown in FIG. 1, but differs from the device shown in FIG. 1 in that it has two reservoir chambers. Components that are the same as those in the apparatus of FIG. 1 are designated by the same reference numerals, and components of the additional storage chamber are designated with a dash in the reference numerals and their description will be omitted. The sub-valves 19, 19' provided at the inlets of the two storage chambers 17, 17' are connected to the crankshaft (not shown).
It opens and closes at the same timing as the sub-valve shown in the wing diagram.

Also, from the opening 29b formed on the caps 29, 29',
9d and 29'b to 29'd are positioned so that the air-fuel mixtures (arrows A and A') ejected from the corresponding warm squares collide with each other and are disturbed. With this configuration, the generation of turbulence is further promoted by the air-fuel mixture ejected from the nozzle, resulting in better combustion. Note that the two air-fuel mixtures ejected from the light port may collide head-on with each other, but the size and direction of the light port should be adjusted so that the air-fuel mixture ejected from one of the air-fuel mixtures ejects from the side of the other air-fuel mixture. You may choose. Further, the opening and closing timings of the sub-valves 19 and 19' may be slightly different from each other. The apparatus shown in FIG. 5 can also be constructed by punching one or more holes in each cap to create a uniform turbulence within the combustion chamber without the turbid air from both nozzles colliding or collapsing. In the present invention, during the compression stroke, the compressed air-fuel mixture can be ejected from multiple terms 〇 in any direction within the combustion chamber to form an almost uniform turbulence in the combustion chamber, and this turbulence will last until the ignition point immediately after the compression stroke. As a result, the flame speed of a mixture with a large amount of exhaust gas recirculated or a lean mixture increases, improving combustion efficiency and reducing cycle-to-cycle combustion fluctuations. Therefore, by employing exhaust gas recirculation or diluted air, the reduction of harmful components in the exhaust gas, the improvement of engine thermal efficiency, and the operational stability of the engine can all be achieved at the same time.

[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 diagram of the valve opening/closing operation of the device shown in FIG. 1, the turtle diagram is a sectional front view of the second embodiment of the present invention, and FIG.
The figure is a sectional front view of the third embodiment of the present invention, and FIG. 6 is a view taken along the line W--W in FIG. 5. 5... Combustion chamber, 7... Piston, 17... Storage chamber, I9... Sub valve "29, 29'... Cap~29a
, 29b, 29c, 29d, 29'a, 29'b, 29
'c, 29'd...Light port. Figure 2 Figure 3 Figure 4 Figure 6 Figure 5

Claims (1)

[Claims] 1. A combustible mixture storage chamber is formed in the cylinder head to temporarily store a part of the combustible mixture introduced into the combustion chamber from the engine intake system, and a valve port is formed in the cylinder head. A sub-valve connected to the combustion chamber through the valve and driven by an engine-driven valve drive cam is provided at the valve port, and the sub-valve controls the opening and closing of the valve port, and the compression stroke starts immediately after the intake valve is closed. The valve is opened over the crank angle range from the time when the ignition timing is reached until the ignition timing is close to the most advanced ignition timing before top dead center and the ignition flame from the ignition plug does not enter the storage chamber. In an internal combustion engine in which a high-pressure combustible mixture stored in a storage chamber is injected into a combustion chamber during the first half of the compression stroke, the opening of the valve port into the combustion chamber is connected to a cap fixed to the inner wall surface of the cylinder head. A combustion chamber of an internal combustion engine which is covered and has a plurality of nozzles formed in the cap.