JPS589252B2 - Jet-controlled combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in internal combustion engines, particularly internal combustion engines for automobiles.

In conventional internal combustion engines for automobiles, the efficiency of intake air into the combustion chamber is poor because it is throttled by the throttle valve, and the flow rate of the intake air flowing into the combustion chamber is low. bad.

Therefore, in general, the above deterioration in ignition and combustibility is solved by supplying a rich mixture with good flammability, that is, a mixture with a low air-fuel ratio. However, there are disadvantages such as an increase in combustion gases HC and CO.

Recently, with the aim of reducing harmful NOx in exhaust gases, it has been proposed to burn a mixture that is sufficiently leaner than the stoichiometric mixture ratio. It has also been proposed to mix it into an air-fuel mixture and combust it, but in either case, the ignitability and combustibility of the air-fuel mixture are reduced, resulting in a disadvantage that drivability and fuel efficiency deteriorate.

Special Publication No. 47-24041 and Special Publication No. 47-43366
The prior art shown in the No. 1 sucks a rich mixture and air or a lean mixture into the cylinder through separate routes, prevents the two from mixing until the point of ignition, and immediately before ignition, the rich mixture is sucked into the cylinder around the spark plug. The air or lean mixture is guided to a location away from the spark plug, ignites the rich mixture, improves ignition combustibility, and achieves lean combustion with a large overall air-fuel ratio. However, this technique has the disadvantage that the device and control become complex in order to always achieve good stratification and guide a rich air-fuel mixture near the spark plug regardless of the operating state.

A main object of the present invention is to provide a jet-controlled combustion engine for vehicles that can improve fuel efficiency.

Another object of the present invention is to be able to stably burn a lean mixture that is difficult to operate stably in a normal engine;
As a result, it is an object of the present invention to provide a jet flow control combustion engine for a vehicle that produces fewer harmful components in exhaust gas.

Still another object of the present invention is to be able to stably burn an air-fuel mixture containing a large amount of recirculated exhaust gas, which is difficult to operate stably in a normal engine, and as a result, the amount of N in the exhaust gas is reduced.
An object of the present invention is to provide a jet flow control combustion engine for a vehicle that can reduce Ox.

Another object of the present invention is to provide a vehicle jet that can stably burn a lean mixture or a mixture containing a large amount of recirculated exhaust gas without causing disadvantages such as a large decrease in output, deterioration of drivability, and deterioration of fuel efficiency. The object of the present invention is to provide a controlled combustion engine.

Still another object of the present invention is to provide a jet-controlled combustion engine for a vehicle that can significantly reduce harmful gas components in exhaust gas and fuel consumption compared to conventional conventional engines, particularly in idling and low-speed, low-load light-load operating regions. be.

The above objects of the present invention are to provide a hemispherical combustion chamber with an intake port opened and closed by a main intake valve and an exhaust port opened and closed by an exhaust valve, and an air-fuel mixture generated by a mixture generation device. A spark gap is arranged at a predetermined position on or near a basic surface forming a hemispherical surface of a cylinder head that forms a main intake passage leading to the combustion chamber via the intake port and the hemispherical combustion chamber. An ignition plug screwed onto the cylinder head, an injection hole provided on the basic surface forming the substantially hemispherical surface near the spark gap and oriented near the spark gap, and a sub-intake air that supplies intake air to the injection hole. This is effectively achieved by a jet-controlled combustion engine comprising a passage and a sub-intake valve for opening and closing the sub-intake passage.

In the internal combustion engine according to the present invention, the ignition combustibility can be improved by adding a simple sub-intake system that injects gas into the cylinder, and moreover, it relates to an improvement of a combustion method that is completely different from the stratified combustion described above. Especially when idling or operating under light load, the throttle opening is small, so the throttling action of the throttle valve is large and the intake air inflow speed from the main intake passage is slow, resulting in a small amount of intake air and a high negative load inside the combustion chamber during the intake stroke. Due to this high negative pressure, air or a lean mixture is sucked in and powerfully injected into the combustion chamber from the injection hole as a high-velocity jet stream. This jet stream scavenges the burnt gas around the spark gap. In addition to improving ignition performance, it generates strong swirl and turbulence within the combustion chamber, and these swirls and turbulence remain during the compression stroke, causing the mixture to flow in a vortex shape, aiding flame propagation after ignition, and promoting combustion. The increased speed extends the lean burn limit and improves fuel efficiency.

Note that the effect of the jet flow described above is not only in idling or light load operating regions where intake efficiency is poor and combustion chamber wall temperature is low and combustibility is poor, but also in medium and high load operating regions where the throttle valve opening is large. It also occurs, albeit to a small extent.

Furthermore, if an exhaust gas recirculation device is used in conjunction with the internal combustion engine of the present invention, deterioration in ignitability and flame propagation velocity due to exhaust gas recirculation can be improved by the jet flow.

As the opening of the throttle valve approaches full opening, the amount of inflow from the intake port, which is normally opened and closed by the main intake valve, increases, the inflow speed of air or lean mixture from the injection hole slows, and the swirl caused by the jet flow increases. The effect becomes less and closer to the conventional combustion mode.

According to the invention, therefore, within the entire operating range of the engine,
An internal combustion engine with low fuel consumption and clean exhaust gas without reducing output or deteriorating drivability is provided.

Next, the present invention will be explained in detail with reference to an embodiment shown in FIGS. 1 to 3.

The main body 1 of a four-stroke multi-cylinder gasoline internal combustion engine for automobiles is mainly composed of a cylinder block 2 and a cylinder head 3. An intake manifold 4 is fixed to one side of the cylinder head 3, and an exhaust manifold 5 is fixed to the other side. It is fixed.

A carburetor 6 is fixed to the upper part of the intake manifold 4, and an air cleaner 7 is further attached to the upper part of the carburetor 6, and the air purified by the air cleaner 7 is formed in the carburetor 6 and the intake 7 in the intake manifold 4. The air is guided through a main intake passage 8 to an intake port 9 formed in the cylinder head 3.

A throttle valve 10 that opens and closes in conjunction with the operation of an accelerator pedal (not shown) is interposed in the carburetor 6 portion of the main intake passage 8, and the intake air is mainly supplied from the upstream side of the position where the throttle valve 10 is installed in the main intake passage 8. Sub-intake passage 1 where part is inhaled
1 is opened in the intake passage wall of the main intake passage 8.

A part of an exhaust gas recirculation passage 13 whose one end communicates with an exhaust port 12 formed in the cylinder head 3 is integrally formed in the intake manifold 4, and the other end of the passage 13 is connected to a main intake passage within the intake manifold 4. is communicated with.

Further, a cooling water passage 14 constituting a heat riser is provided at the lower part of the intake manifold 4, and a thermosensor 15 is attached to the passage 14.

Further, a control valve 16 for controlling the amount of recirculation is interposed in the middle of the exhaust gas recirculation passage 13, and the control valve 16 is controlled by an actuation device 17 that provides a desired opening depending on the operating state of the engine.

Specifically, the actuating device 17 is one that mechanically interlocks with the opening degree of the throttle valve 10, or an actuating device that operates in a specific position within the main intake passage 8 that is determined in particular in relation to the throttle valve 10. There are some that pneumatically control depending on the magnitude of the pressure.

The thermosensor 15 detects whether the engine is cold or overheated based on the engine cooling water temperature, and controls the exhaust gas recirculation amount control valve 16 or an ignition advance control device (not shown).

Furthermore, the exhaust manifold 5 that communicates with the exhaust port 12 of each cylinder is formed into an upper and lower two-part structure that is screwed into place by bolts 18, and the exhaust manifold 5 has a gathering part where the exhaust gas is connected, as shown by the arrow in FIG. A radial flow type catalyst layer 19 whose axis of flow is vertical is built in, and the lower part of the exhaust manifold 5 is connected to an exhaust pipe 20.

Next, the internal configuration of the main body 1 will be explained with reference to FIGS. 2 and 3. The inner peripheral surface of the cylinder 21 formed in the cylinder block 2, the top surface of the piston 22, and the hemispherical basic surface of the cylinder head 3. A hemispherical combustion chamber 24 is defined by a concave surface 23 along the concave surface 23, and the intake port 9 and exhaust port 12 are opened at predetermined positions of the concave surface 23.

The spark plug 25 is screwed into a through hole 26 formed in the cylinder head 3, and the spark gap 21 of the spark plug 25 is located on or near the basic surface of the concave surface 23.

Further, a through hole 28 that opens adjacent to the spark gap 21 is bored in the concave surface 23, and a hollow cylindrical jet piece 30 is press-fitted into the through hole 28 from the combustion chamber 24 side, and from the opposite side. When the jet body 32 is fitted, the male screw part provided on the outer circumferential surface of the end of the jet body 32 and the female thread part provided on the inner circumferential surface of the end of the jet piece 30 are screwed together. It is fixed to the cylinder head 3 with the contact surfaces 33 and 34 sandwiched between them.

A mushroom valve-shaped auxiliary intake valve 35 is slidably fitted into the jet body 32, and a gap is formed between the outer circumferential surface of the auxiliary intake valve 35 and the inner circumferential surface of the jet body 32 at the female threaded end of the jet body 32. A sub-intake passage 36 having an annular cross-sectional shape is formed by curing the area, and the sub-intake passage 36 connects the inner circumferential surface of the through hole 28 and the outer circumferential surface of the jet body 32 through a hole 37 formed in the jet body 32. The passage 38 is further communicated with a sub intake passage 39 formed in the cylinder head 2, and the passage 39
is connected to the sub-intake passage 11.

The auxiliary intake passage 36 has a small volume injection chamber 4 surrounded by the inner surface of the jet piece 30 and the end face of the umbrella portion of the auxiliary intake valve 35.
0, and the opening is closed when the umbrella portion of the sub-intake valve 35 comes into contact with a valve seat 41 formed at the tip of the jet body 32.

The part of the jet piece 30 exposed to the combustion chamber 24 is configured in a hollow shell shape, and an injection hole 42 communicating between the combustion chamber 24 and the injection chamber 40 is bored in this shell.
Reference numeral 2 is provided at a position close to the spark gap 27 of the ignition plug 25 and on a substantially extended surface of the concave surface, and is an air-fuel mixture sucked into the combustion chamber 24 from the intake port 9 in a direction near the gap 11. It is directed in the forward direction with respect to the swirl direction shown by arrow a in FIG.

In addition, in FIGS. 2 and 3, the direction of injection from the injection hole 42 is indicated by an arrow X.

The main intake valve 43 that opens and closes the intake port 9 and the sub-intake valve 35 are both mushroom valves driven by the same rocker arm 44, and the rocker arm 44 is driven by the rocker shaft 45.
The arm part on the opposite side of the contact surface to the cam 47 branches into two parts, and each Adjustment screws 48 and 49 are screwed into the branch portions, respectively.

The end surface of the adjusting screw 48 is in contact with the upper end surface of the valve stem of the main intake valve 43 , and the end surface of the adjusting screw 49 is in contact with the end surface of the valve stem of the sub-intake valve 35 .

Note that 50 and 51 are valve springs, and 52 and 53 are retainers.

Further, the exhaust valve 54 that opens and closes the exhaust port 12 is opened and closed by the swinging of a rocker arm 56 fitted to a rocker seat 55, and the rocker arm 56 contacts a cam 57 provided on the camshaft 46 and swings.

In addition, 58 is an adjustment screw, 59 is a valve spring, and 60 is a retainer.

According to the above configuration, when the main intake valve 43 and the auxiliary intake valve 35 open during the intake stroke, the negative pressure generated in the combustion chamber 24 causes the air-fuel mixture produced in the carburetor 6 to circulate in the intake manifold 4. After mixing, some of the intake air is drawn into the combustion chamber 24 from the intake port 9 while creating a swirl along the inner peripheral surface of the cylinder 21 as shown by arrow a in FIG. Mainly from the upstream side of the throttle valve 10 of the main intake passage 8 to the auxiliary intake passage 3
6 into the injection chamber 40.

The air sucked into the injection chamber 40 is injected into the combustion chamber 24 through the injection hole 42 and scavenges the burnt gas around the spark gap 27, as well as the concave surface 23 of the cylinder head 3 and the inner periphery of the cylinder 21. Jet turbulence is generated within the combustion chamber as it flows down along the surface.

Therefore, the jet stream gives a strong swirl to the air-fuel mixture taken into the combustion chamber 24, and also mixes with the air-fuel mixture moderately to dilute the air-fuel mixture.
1. Scavenge the surrounding area to improve ignitability and combustibility.

Furthermore, when ignited in the spark gap 27 in the latter half of the compression stroke, part of the flame enters the injection chamber 40 through the injection hole 42, and the injection chamber 40 is a small chamber, and the air-fuel mixture in the combustion chamber 24 during the compression stroke. As a result of strong turbulent flow occurring when the mixture flows into the injection chamber 40, the air-fuel mixture that has flowed into the injection chamber 40 is rapidly combusted and becomes high temperature and high pressure, causing flames to flow vigorously from the injection hole 42 into the combustion chamber 24. This jet also promotes the ongoing combustion within the combustion chamber 40.

By the way, the protrusion of the spark plug 25 and jet piece 30 from the concave surface 23 into the combustion chamber 24 must be suppressed as much as possible to prevent premature ignition and to generate effective swirl. If the amount of protrusion of the spark plug 25 or the jet piece 30 is too large, the heat transfer to the cylinder head 3 will be reduced and the cooling performance will be deteriorated, and the protrusion of the spark plug 25 or the jet piece 30 will be overheated by combustion heat, causing overheating. Causes premature ignition, and
In extreme cases, it may cause problems such as melting and damage.

Furthermore, the ignition ram 25 or jet piece 30
Excessive protrusion may impede effective swirl generation in the hemispherical combustion chamber 24, which is most effective for swirl generation, which is undesirable.

In the embodiment described above, the amount of protrusion of the spark plug 25 and jet piece 30 is suppressed as much as possible, and the spark gap 27 is arranged on or near the basic surface of the concave surface 23 along the hemispherical basic surface. At the same time, the injection holes 42 are also provided substantially on the basic surface of the concave surface 23, and the direction in which the injection holes 42 are directed is near the spark gap 27 and along the concave surface 23.
The occurrence of the above-mentioned malfunction is prevented, and the injection hole 42
The jet stream from the spark gap reliably scavenges the vicinity of the spark gap, and is guided by the concave surface 23 to generate an effective swirl.

Further, in the embodiment described above, the center line of the injection hole 42 is not directed directly toward the spark gap 27, but is oriented at a position shifted from the spark gap 27 position by 3 to 10 mm.

This is because if the center line of the injection hole 42 is directly directed toward the spark gap 27, the stability at idle and low temperature startability will deteriorate somewhat. In the operating range where the ratio of the injection amount is large, the vicinity of the spark gap 27 is supercooled, and the intake air in the vicinity becomes too thin, deteriorating the ignition performance.In addition, the choke valve is generally operated at low temperature starting, so the secondary This is thought to be due to the fact that a rich air-fuel mixture is sucked into the intake passage 11 and the raw gas directly hits the ignition plug 25, tending to cause so-called ignition plug fogging.

Further, in the above embodiment, the distance L between the center line of the injection hole 42 and the center line of the cylinder 21 is L with respect to the diameter D of the cylinder 21.
Bow 0. The jet flow from the injection hole 42 collides with the concave surface 23 or the inner peripheral surface of the cylinder 21 and is attenuated by setting it within this range. It makes the intake air-fuel mixture strong and generates a good swirl.

Furthermore, in the above embodiment, when the diameter d1 of the injection hole 42 is set within the range of (mu)2L: 0.001 to 0.017, the injection effect from the injection hole 42 is good, and d1 is within the above range. If d1 is smaller, the flame may not be able to enter the injection chamber 40 after ignition, and the jet flow rate will be too small. If d1 is too large, the directivity and strength of the jet flow will be reduced. Therefore, the fuel consumption reduction effect of the jet flow is significantly reduced.

Further, in the above embodiment, the distance Y between the spark gap 27 and the injection hole 42 may be set within a range of about 3 mm to 20 mm, and if Y becomes 3 mm or less, the ejection of the jet stream will be inhibited by the spark plug 25. Otherwise, the spark gap 27 portion may become supercooled, and if Y becomes 20 mm or more, the scavenging effect and flow effect around the spark gap 27 decreases, resulting in a decrease in ignitability.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing one embodiment of the present invention, and FIG. 2 is a schematic diagram showing an embodiment of the present invention.
FIG. 3 is an enlarged sectional view of the main part of the figure, FIG. 3 is a Z--Z arrow diagram in FIG. 2, and FIG. 4 is an explanatory view of the concave surface of the combustion chamber in FIG. 2. 1... Internal combustion engine body, 2... Cylinder block, 3... Cylinder head, 4...
...Intake manifold, 5...Exhaust manifold,
6... Carburizer, 8... Main intake passage, 9
... Intake port, 10 ... Throttle valve, 1 1 , 36 , 38 . 39...
・Sub-intake passage, 12...Exhaust port, 21...
... Cylinder, 23 ... Concave surface, 24 ...
・Combustion chamber, 25...Spark plug, 21...
...Spark gap, 30...Jet piece, 132...Jet body, 35...
...Sub-intake valve, 37...hole, 40...
Injection chamber, 42...Injection hole, 43...Main intake valve, 54...Exhaust valve.

Claims (1)

[Scope of Claims] 1. A hemispherical combustion chamber having an intake port opened and closed by a main intake valve and an exhaust port opened and closed by an exhaust valve; a main intake passage leading to the combustion chamber through the port;
An ignition plug screwed onto the cylinder head such that a spark gap is located at a predetermined position on or near a basic surface forming a hemispherical surface of the cylinder head forming the hemispherical combustion chamber, and an abbreviation of the area near the spark gap. It includes an injection hole provided on the basic surface forming the raw spherical surface and oriented near the spark gap, an auxiliary intake passage that supplies intake air to the injection hole, and an auxiliary intake valve that opens and closes the auxiliary intake passage. jet-controlled combustion engine. 2. A jet flow control combustion engine according to claim 1, in which the center line of the injection hole is oriented to be deviated from the spark gap by 3 to 10 mm. 3. In the engine according to claim 1, the distance L between the center line of the injection hole and the center line of the cylinder is within the range of 0.15D to 0.40D for each cylinder diameter, and A jet flow control combustion engine, wherein the direction of injection from the injection hole is in the forward direction with respect to the swirl direction given to the air-fuel mixture taken in from the intake port. 4. A jet flow control combustion engine according to claim 3, wherein the injection holes are oriented along a basic hemispherical surface of the cylinder head.