JPS5941009B2 - engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in engines, particularly automobile engines.

In conventional automobile engines, during idle operation and light load operation, the opening of the throttle valve is small and the amount of intake air is small, so the speed of the air-fuel mixture flowing into the cylinder from the intake manifold during the intake stroke is low. The swirl of the mixture inside the cylinder is also weak.

As a result, at the time of ignition, which normally occurs at the end of the compression stroke,
The swirl of the air-fuel mixture remaining in the cylinder also becomes weaker, resulting in lower ignition and combustibility, so to ensure stable engine operation, supply a mixture with a lower air-fuel ratio than during medium and high load operation. This not only increases fuel consumption, but also reduces C in the exhaust gas due to incomplete combustion of rich mixtures.
There is a disadvantage that O and HC increase.

Recently, with the aim of reducing CO, HC, and especially NOx in engine exhaust gas, it has been proposed to burn a mixture that is sufficiently leaner than the stoichiometric mixture ratio. It has also been proposed to extract part of the exhaust gas from the engine's exhaust system and mix it into the mixture and burn it, but in either case, the ignitability and combustibility of the mixture will be low, so There have been disadvantages in that drivability during driving and light load operation is reduced, and fuel efficiency is also deteriorated.

A primary object of the present invention is to provide a vehicle engine that can improve fuel efficiency, particularly during idle and light load operation.

Another object of the present invention is to be able to stably burn a lean air-fuel mixture that is difficult to operate stably at idle and under light load in a normal engine, and as a result, to reduce harmful components in exhaust gas. Our goal is to provide the following engines.

Still another object of the present invention is to be able to stably burn a mixture containing a large amount of recirculated exhaust gas, which is difficult to operate stably at idle and under light load in a normal engine. An object of the present invention is to provide a vehicle engine capable of reducing NOx.

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

Still another object of the present invention is to provide a vehicle engine that can reduce harmful gas components in exhaust gas in the idling and low-speed, low-load light-load operating ranges compared to conventional conventional engines.

The aspects of the present invention are as follows: The spark gap of the ignition plug is faced into the combustion chamber, and a gas such as air-lean mixture exhaust gas is injected near the spark gap toward the set direction of the combustion chamber. In an engine provided with holes, a main intake passage supplies intake air to the combustion chamber via a main intake valve, a throttle valve provided in the main intake passage to control the intake air flow rate, and an intake passage that communicates with the injection hole and is connected to the injection hole. and a control valve that opens and closes the sub-intake passage and operates in conjunction with the throttle valve, and when the throttle valve opening is medium, the control valve is set to the maximum opening. This is effectively achieved by an engine characterized in that it is configured to:

The gas supplied to the sub-intake passage is preferably air, but may be a lean mixture of fuel and air, or may be exhaust gas from the engine itself.

When the above gas is air, the supply source of the above gas is the atmosphere, and in the case of a lean mixture, the intake manifold is suitable as the gas supply source for an engine with a carburetor, and furthermore, in the case of exhaust gas, the exhaust manifold is suitable as the gas supply source. Serves as a gas supply source.

In the above-mentioned engine according to the present invention, the throttle opening is small especially during idling and light load operation, so the throttling action of the throttle valve is slow and the intake air inflow speed from the main intake passage is slow, resulting in a small amount of intake air during the intake stroke. In the combustion chamber, there is a high negative pressure, and the gas from the gas supply source is attracted by this strong negative pressure in the combustion chamber and is injected from the injection hole in a set direction inside the combustion chamber, creating a strong vortex or turbulent flow inside the combustion chamber. This increases the combustion speed, extends the lean burn limit, and improves fuel efficiency.Furthermore, when the jet from the injection hole acts around the spark gap of the ignition plug located in the combustion chamber, scavenging of the combustion gas occurs. In addition to improving ignition performance, the scavenging action also extends the lean burn limit.

Therefore, even if lean mixture combustion is performed in the idle link or light load operating ranges where the air-fuel mixture distribution is poor (and the combustion chamber wall temperature is low and combustibility is poor), the decrease in output and increase in fuel consumption can be kept to a minimum. Moreover, the maximum combustion temperature decreases due to the increase in the air-fuel ratio, and the amount of NOx generated is extremely reduced.

Furthermore, if an exhaust gas recirculation device is used in conjunction with the engine of the present invention, the amount of NOx generated can be easily reduced without setting the air-fuel ratio, which is difficult to control, to a high value close to the combustion limit. The deterioration of ignitability and flame propagation speed due to reflux is also improved by the upper air jet.

Further, according to the engine of the present invention, the gas flow rate supplied through the auxiliary intake passage is supplied according to characteristics particularly suitable for improving fuel efficiency.

A first embodiment of the present invention will be described below with reference to FIGS. 1 to 5.

10 is a main body of an automobile gasoline internal combustion engine, 12 is a cylinder head, 14 is a cylinder block, 16 is a piston,
18 is a combustion chamber, 20 is a spark plug, 22 is a main intake port, 24 is an exhaust port, 26 is a main intake valve, 28 is an intake manifold, 30 is a carburetor, and 32 is an air cleaner.

The cylinder head 12 has an injection hole 3 that opens into the combustion chamber 18.
4 is drilled, and the injection hole is located in the spark gap 3 of the spark plug 20.
The piston 16 is oriented directly below the piston 160 and has a set angle of, for example, about 300 to 60 degrees with the top surface of the piston 160.
oriented in a direction.

Further, the injection hole 34 is connected to a sub-intake passage 40 via a sub-intake valve 38.

The main intake valve 26 and the sub-intake valve 38 are both mushroom valves driven by the same rocker arm 42, and the rocker arm is fitted into a rocker shaft 44, which is a camshaft that is rotated in conjunction with the crankshaft of an engine (not shown). 46
It comes into contact with a cam 48 provided on the cam 48 and swings.

Further, the arm portion of the rocker arm 42 on the side opposite to the contact surface with the cam 48 branches into two parts, and adjusting screws 50 and 52 are screwed into each branch part, respectively, and the end face of one adjusting screw 50 is screwed into each branch part. The upper end surface of the valve stem of the main intake valve 26 is in contact with the upper end surface of the valve stem, and the end surface of the other adjusting screw 52 is in contact with the end surface of the valve stem of the auxiliary intake valve 38 .

Note that 54 and 56 are valve springs, 58 and 60 are spring seats, and 62 is a valve guide for the sub-intake valve 38.

A main intake passage 63 that communicates from the air cleaner 32 to the intake port 22 via the carburetor 30 and the intake manifold 28
A primary port 64 and a secondary port 65 are provided in the carburetor part of the unit, and venturi ports 66 and 67 are provided respectively.
and throttle valves 58, 69 are arranged.

An idle port TO and a slow port 72 are bored on the inner wall of the intake passage in the vicinity of the fully closed position of the throttle valve 68 to supply fuel mainly during idle or light load.
An adjustment screw (not shown) is provided at the idle port TO.

On the other hand, the venturi 66°6T is provided with main nozzles 76 and 77 that supply fuel mainly during medium and high loads.

An exhaust gas recirculation passage 78, which is connected at one end to an exhaust passage (not shown) to an exhaust manifold, for example, is connected to a control valve 80 that detects various operating conditions of the engine and controls the flow rate of exhaust gas. It is connected to the gathering part of the manifold 28.

Further, the auxiliary intake passage 40 is communicated with the main intake passage 63 upstream of the venturi 67 via a pipe 82 that is integrally cast into the intake manifold 28.

Reference numeral 90 denotes a control device provided in the sub-intake passage 40, which includes an intake system negative pressure passage whose one end communicates directly upstream of the fully closed position of the throttle valve 68 and whose other end communicates with a negative pressure chamber 94 having a diaphragm 92. 96, a thermovalve 98 for opening the intake system negative pressure passage 96 to the atmosphere, and a control valve 100 connected to the diaphragm 92.

102 is installed inside the negative pressure chamber 94 and connects the diaphragm 9
2, which biases the control valve 100 in the closing direction.

The thermovalve 98 includes a heat sensitive part 106 inserted into a heat riser 104 provided in the intake manifold 28 and into which engine cooling water is introduced, a thermally expandable thermowax 108 disposed inside the heat sensitive part 106, and a thermowax 108 with thermal expansion property installed inside the heat sensitive part 106. 10
8, an atmosphere release valve 114 that connects the intake system negative pressure passage 96 to the atmosphere release passage 112 by actuation of the rod 110, and an atmosphere release valve 114 that urges the atmosphere release 114 in the closing direction. It has a spring 116 and an air cleaner 118.

39 is a throttle provided in the bypass passage 41 of the sub-intake passage 40.

The control device 90 operates according to the negative pressure characteristics of a negative pressure chamber communicated immediately upstream of the fully closed position of the throttle valve 68, indicated by a solid line A in FIG. 5, and opens the sub-intake passage 40 in proportion to the negative pressure. Get degree.

In FIG. 5, the solid line B is the percentage of flow rate (relative to the total intake air amount) supplied only by the bypass passage 41, the solid line C is the percentage of flow rate supplied by the auxiliary intake passage 40 and the bypass passage 41, and the two-dot chain line is equivalent fuel efficiency improvement. shows the rate characteristics, X is 10%
, Y indicates a fuel efficiency improvement rate of 5%, and Z indicates a fuel efficiency improvement rate of 2%.

According to the above configuration, when the engine is at temperature, the thermovalve 98 communicates with the intake system negative pressure passage 96 as shown by the dashed line in FIG. 1, so that the throttle valve 68 shown in FIG. Negative pressure immediately upstream of the fully closed position is supplied, and the opening degree of the auxiliary intake passage 40 is obtained in proportion to the negative pressure, and the solid line C
Accordingly, gas is injected from the injection hole 34 of the combustion chamber 18.

On the other hand, most of the air taken into the main intake passage 63 from the air cleaner 32 is mixed with fuel at a predetermined air-fuel ratio in the carburetor 30 and taken into the combustion chamber 18 through the intake port 22.

The amount of injection from the injection hole 34 and the strength of the jet flow are determined by the opening of the throttle valve 68, that is, the load of the engine, and the auxiliary intake passage 4.
It changes according to the opening degree of the control valve 100 provided at 0.

That is, during idling with a small throttle opening or under light load, the amount of air-fuel mixture supplied from the main intake passage 63 is small due to the throttling action of the throttle valve 68, and a high negative pressure is generated in the combustion chamber 18 during the intake stroke, causing the venturi Since the main intake passage 63 on the upstream side of the main intake passage 66 is at approximately atmospheric pressure, a large amount of air is powerfully injected into the combustion chamber 18 from the injection hole 34 via the auxiliary intake passage 40 due to the pressure difference.

As a result, the air-fuel mixture sucked into the combustion chamber 18 generates a strong vortex or turbulence due to the jet flow of air, and the mixture of air sucked from the main intake passages 6 and 3 becomes stratified or non-uniform. Diluted in spots.

Furthermore, since the above-mentioned jet stream passes near the spark gap 36 of the ignition plug 20, the residual combustion gas near the spark gap 36 is also induced and scavenged, and new intake mixed gas flows into the vicinity of the spark gap. do.

Therefore, even at the time of ignition, which occurs in the latter half of the compression stroke, there is a strong vortex or turbulent flow with the air and mixture distributed in a layered or patchy manner, and the spark gap 36
It is thought that the intake air-fuel mixture is constantly flowing in the vicinity, and experiments have shown that compared to conventional engines, the flame propagation speed is improved, the misfire limit is dramatically expanded, and fuel efficiency is improved. Even when the air-fuel mixture is diluted, there is little decrease in output (
It was confirmed that drivability was improved.

In addition, the intake manifold 28 is connected via the exhaust gas recirculation passage 78.
The amount of exhaust gas sucked into the engine is controlled by the control valve 80, and the amount of exhaust gas recirculated is adjusted so as to suppress the amount of NOx discharged within a set value.

Next, in a medium load operating region where the throttle opening is medium, the throttling effect by the throttle valve 68 is medium and the differential pressure between the auxiliary intake passage 40 and the main intake passage 63 is slightly small. Since the 900 control valve 100 is at its maximum opening as shown by the two-dot chain line, a relatively large amount of air is supplied and injected, sufficiently compensating for the decrease in differential pressure.

On the other hand, in a high-load operation region where the throttle opening is large, the throttling action by the throttle valve 68 is small and a large amount of air-fuel mixture is sucked into the combustion chamber 18 through the main intake passage 63. As shown by the solid line (since the auxiliary intake passage 40 is closed, the injection amount and injection force from the auxiliary intake passage 40 are performed only through the bypass passage 41, so they are reduced and the swirl effect of the injection air is also reduced. ,
In this case, the intake efficiency is poor, and when the air-fuel mixture flows into the combustion chamber 18 from the intake port +-22, a strong vortex or turbulent flow is generated, and the temperature of the inner wall of the combustion chamber 18 also rises. The jet flow from the injection hole 34 does not generate strong vortices or turbulence (but the flame propagation velocity is high and the combustibility is good).

Furthermore, when the engine is cold, the thermovalve 98 opens the intake system negative pressure passage 96 to the atmosphere as shown by the solid line in FIG.
00 closes the sub-intake passage 40.

Particularly when the engine is started in a cold state, the combustion within the combustion chamber 18 is extremely unstable, and the combustion limit maximum air-fuel ratio is significantly reduced. The air-fuel mixture formed by No. 30 is supplied, and the air-fuel ratio does not become excessive due to the injection air, so that stable combustion can be performed even in a cold state.

As is clear from the above, according to this embodiment, the combustion chamber 1
In a light load operating region with poor combustion conditions such as a relatively low inner wall temperature of the combustion chamber 18 and poor intake efficiency, the mixture containing part of the exhaust gas is further mixed with air flowing in from the injection holes 34 in the combustion chamber 18. It is possible to stably burn not only a mixture with a total air-fuel ratio of about 11 to 14, but also a lean mixture with a total air-fuel ratio of about 15 to 21, which has poor combustibility. At this time, a strong vortex or turbulent flow is generated due to the powerful air jet from the injection hole 34, and
The injected air is mixed with the air-fuel mixture taken in from the main intake passage 63 in an appropriate stratified or patchy state, so that N
The combustion speed is improved without increasing the amount of Ox generated, shortening the combustion completion time, reducing fuel consumption and improving drivability, and also reducing the amount of unburned gas emissions such as HC and CO. This effect is achieved.

In the second embodiment shown in FIGS. 6 and 7, a throttle valve 120 is provided in the sub-intake passage 40, a lever 122 of the throttle valve 120 has a length of 11 mm, and a throttle valve 68 is attached via a rod 124. The length of the lever 126 is 12
In this case, by setting 1□ (12), the opening degree of the throttle valve 68 and the opening degree of the throttle valve 120 are set to be approximately the same as those shown in FIG. 5 of the first embodiment. The structure also provides the same effects as the first embodiment.

At this time, the throttle valve 120 is arranged so that it does not completely block the auxiliary intake passage 40 even in the fully closed or fully open position (with a predetermined gap δ1, δ2).

In the third embodiment shown in FIG. 8, the upstream end of the sub-intake passage 40 is opened to the discharge part of the secondary air supply pump, which is supplied to promote the oxidation reaction of unburned components in the normal exhaust system. In addition, the bypass passage 41 has a restriction 39.
It opens upstream of the venturi 76,77 through.

Suitable embodiments of the secondary air supply pump are shown in FIGS. 9 to 12.
This will be explained according to the diagram.

Reference numeral 210 indicates a 4-cylinder automobile engine body, and 21
2 generally shows a diaphragm pump for supplying secondary air for exhaust gas purification to an engine exhaust system (not shown).

Each cylinder 214°216.21 of the engine main body 210
A plurality of partition walls 228 are arranged substantially parallel to each other in the lower part of the cylinder block 222 forming a bearing 226 for a crankshaft 224 .

Between each partition wall 228 are crank chambers 232, 234° 23 in which one crank 230 of the crankshaft 224 is built.
6.238 are formed, and the crank chambers 232°, 234.
The upper portions of the cylinders 236 and 238 communicate with the cylinders 214 to 220, and the lower portions thereof open into the oil pan 240.

Each partition wall 2 adjacent to the cylinder 214 and the cylinder 218
A partition plate 244 is fixed to the lower part of the cylinder 26 by bolts 242, and the partition plate 244 separates the crank chamber 232 communicating with the cylinder 214 and the crank chamber 236 communicating with the cylinder 218 from other crank chambers and the inside of the oil pan 240. are doing.

The partition plate 244 has fitting holes 24 for bolts 242.
6 is bored, and an oil drain hole 248 is bored in the center of the curved bottom plate.

The diaphragm pump 212 has two diaphragms 252 and 254 arranged in parallel in a housing 250, with a partition plate 256 interposed between the two diaphragms 252 and 254.
Two pump chambers 258°260 are formed, and the diaphragm 2
A pressure chamber 262 partitioned by 52 is communicated with the crank chamber 232 via an air passage 264.
A pressure chamber 266 partitioned by 4 is communicated with the crank chamber 236 via an air passage 268.

Rondo 27 slidably penetrates the center of the partition plate 256
Both ends of the diaphragm 252 and 254 are connected to the center of each diaphragm 252 and 254, respectively.

Each diaphragm 252°2 is installed in the pump chamber 258.260.
Built-in springs 272 and 274 that press 54,
The pump chamber 258 is connected to the suction port 2 via the reed valve 276.
78 is opened to the outside air, and the reed valve 28
0 and is connected to a discharge port 282 through which air is pumped.

Furthermore, the discharge port 282 is communicated with a suitable location in the engine exhaust system, such as a thermal reactor or a catalytic converter, or an exhaust gas passage upstream of these exhaust purification devices, via a conduit (not shown).

The pump chamber 260 also communicates with the suction port 278 via a reed valve 284 and with the discharge port 282 via a reed valve 286.

In addition, 285 is a flywheel connected to a clutch (not shown), 287 is a piston fitted to each cylinder 214 to 220, and 288 is a piston 287 and a crank 2.
30 is a connecting rod, 290 is lubricating oil, 292 is an oil strainer, 294 is a cooling fan,
296 is a cap bolt of the bearing 226.

The operation of the pump device configured as described above will now be explained.

As is well known, in a general four-cylinder engine, cylinder 214
The crank mounting angles for the pistons of and 220 are the same,
Further, the crank angles of the pistons of cylinders 216 and 218 are equal, and they have a phase shift of 180°.

Now, when the piston of the cylinder 214 descends, the crank chamber 23
The air in the diaphragm pump 212 is compressed, and some of the air flows out from the oil drain hole 248 or the gap between the partition wall 228 and the partition plate 244 and becomes high pressure. is transmitted to chamber 262.

On the other hand, when the piston in the cylinder 214 descends, the cylinder 218
As the piston inside rises, the air inside the crank chamber 236 expands and spreads to other crank chambers or the oil pan 240.
Some air flows into the crank chamber 236 from inside through the oil drain hole 248 and the like, resulting in low pressure, and this low pressure is transmitted to the pressure chamber 266 via the air passage 268.

Therefore, the crank chamber 232 and the crank chamber 236 are
The pressure changes once from high pressure to low pressure for each revolution of the engine, and the pressure rises and falls at opposite times between the compartments, and the difference in air pressure in both pressure chambers 262 and 264 occurs for each revolution of the engine. The pressure is reversed, which activates the differential pressure responsive pump 212.

That is, when the pressure in the pressure chamber 262 is high and the pressure in the pressure chamber 264 is low, the diaphragms 252 and 254
72 and is displaced to the right in FIG. 9, pump chamber 2
The air in the pump chamber 260 is compressed and the reed valve 280 opens and is sent out from the discharge port 282, and the air in the pump chamber 260 expands and the reed valve 284 opens and the atmosphere is sucked into the pump chamber 260 through the suction port 278.

Conversely, when the pressure in the pressure chamber 262 is low and the pressure in the pressure chamber 266 is high, the diaphragms 252 and 254
74 to the left in FIG. 9, the reed valve 2γ6 opens, and the atmosphere is sucked into the pump chamber 258.
The reed valve 286 opens and the air inside the pump chamber 260 is sent out from the discharge port 282.

Here, both diaphragms 252, 254 and rod 2γ
0 is based on the set tension of the springs 272 and 274 (
It has a unique vibration (reciprocating) period, and the pump characteristics change by changing the set tension, but in this example, the period is set below the engine's medium rotational speed, so the engine's During high-speed rotation, the vibrating body such as the condo 212 becomes unable to follow the fluctuation cycle of the air pressure, and the operation of the pump 212 is automatically stopped and the pump 212 enters a non-operating state.

According to the above pump device, air flow characteristics as shown in FIG. 12 can be obtained.

In addition, in the above FIG. 12, the solid line indicates both springs 27.
The broken line shows the air flow characteristics when the set tension of both springs 272 and 274 is made small.
By adjusting the set tension of 72.274, it is possible to set the air flow rate itself and the engine speed range where the air flow rate rapidly decreases to a desired value, and the air flow rate is sent out from the discharge port 282 of the pump device. The air flow rate characteristics are suitable for the flow rate characteristics of the auxiliary intake passage 40 shown in FIG. 5 of the first embodiment described above.

Furthermore, the flow rate is controlled by the control valve device 90 similar to the first embodiment, and even if there is no discharge amount from the discharge port 282 or the control valve 100, the intake passage 40, and the intake passage 40 are completely closed, the bypass passage 41 A small amount of air is supplied through the

Next, a fourth embodiment of the present invention shown in FIGS. 13 to 16 will be described.

In the fourth embodiment of the present invention shown in FIGS. 13 to 16, 310 is a main body of an automobile gasoline internal combustion engine, 312 is a cylinder head, 314 is a cylinder block, 316 is a piston, 318 is a combustion chamber, and 320 is a spark plug. , 322
324 is the main intake port, 324 is the exhaust port, 326 is the main intake valve, 328 is the intake manifold, 330 is the carburetor, 332
is an air cleaner.

The recess in the cylinder head 312 that limits the combustion chamber 318 has a hemispherical shape, and the spark gap 33 of the spark plug 320
4 is disposed near the extension surface of the spherical wall surface 336 in the center of a small recess 338 provided in the spherical wall surface 336 forming the combustion chamber 318 of the cylinder head 312.

Further, a through hole 340 is formed in the cylinder head 312 and is open adjacent to the small recess 338 and whose center line is at an angle of approximately 60 degrees with the top surface of the piston 316.
From the side of the combustion chamber 318, there is a hollow cylindrical injection chamber forming member 3.
42 is fitted, and the valve guide 344 is fitted from the opposite side, and the male threaded part provided on the outer peripheral surface of the end of the valve guide 344 and the female threaded part provided on the inner peripheral surface of the end of the injection chamber forming member 342 are screwed together. By fitting them together, both are connected to the through hole 34.
It is fixed to the cylinder head 312 by sandwiching the small diameter portion 346 inside the cylinder.

A sub-intake valve 348 is slidably fitted into the valve guide 344, and a cross-sectional shape is formed with a gap between the outer peripheral surface of the sub-intake valve 348 and the inner peripheral surface of the valve guide 344 on the female threaded portion side of the valve guide 344. forms a circular sub-intake passage 350,
The auxiliary intake passage 350 communicates with a auxiliary intake passage 354 formed in the cylinder head 312 through a hole 352 formed in the valve guide 344, and opens into an injection chamber 356 in the injection chamber forming member 342. The opening is closed when the umbrella portion of the sub-intake valve 348 comes into contact with a valve seat 358 formed at the tip of the valve guide 344.

The injection chamber forming member 342 is provided to protrude into the main combustion chamber 318, and an injection hole 360 that communicates the injection chamber 356 and the main combustion chamber 318 is bored in the protrusion, and the injection hole 360 is located near the spark gap 334. In addition, it is located directly below the spark gap 334 and in the cylinder head 312.
It is oriented in a direction substantially along the zero spherical wall surface 336.

The main intake valve 326 and the sub-intake valve 348 are both mushroom valves driven by the same rocker arm 362, and the rocker arm 362 is fitted with a rocker shaft 364, and a cam 368 is installed on a camshaft 366 that is rotated by the engine. The arm portion opposite to the contact surface of the cam 368- is bifurcated into two, and adjustment screws 370 and 372 are screwed into each bifurcated portion.

The end surface of the adjust screw 370 contacts the upper end surface of the valve stem of the main intake valve 326, and the end surface of the adjust screw 372 contacts the end surface of the valve stem of the sub-intake valve 348.

In addition, 374, 376 are valve springs, 378.3
80 is a spring seat, and 382° and 384 are seal rings.

According to the above configuration, the main intake passage 6 is
Most of the air sucked into the combustion chamber 318 is mixed with fuel at a predetermined air-fuel ratio in the carburetor 30 and sucked into the combustion chamber 318 through the intake port 322, while a portion of the air is sucked into the combustion chamber 318 through the pipe 82 and the auxiliary intake passage. Injection chamber 35 via 354, 350
6 and is injected into the combustion chamber 318 from the injection hole 360.

The amount of injection and the strength of the jet stream from the injection hole 360 change depending on the opening degree of the throttle valves 68, 69, that is, the load of the engine. As a result, the amount of air-fuel mixture supplied from the main intake passage 63 is small (extra high negative pressure is generated in the combustion chamber 318 during the intake stroke, and the venturi 6
6.67 Since the main intake passage 63 on the upstream side is at approximately atmospheric pressure, a large amount of air is forcefully ejected from the injection hole 360 due to the pressure difference, and this ejected flow passes near the spark gap 334 and closes the same gap. The burned gas around 334 is scavenged and flows down along the spherical wall surface 336,
Strong swirl and turbulence are imparted to the air-fuel mixture taken in through the intake port 322, and these swirls and turbulence remain even during the compression stroke, distributing the air-fuel mixture and air in a layered or patchy manner, and preventing flame propagation after ignition. It is presumed that it plays a role in helping people.

Furthermore, when ignited in the spark gap 334, a part of the flame enters the injection chamber 356, and since the injection chamber 356 is a small chamber, it is rapidly combusted and becomes high temperature and high pressure, and the flame moves vigorously from the injection hole 360. It is believed that this jet is forced into the main combustion chamber 318 and also promotes the ongoing combustion within the main combustion chamber 318.

On the other hand, in a high-load operation region with a large throttle opening, the throttling action of the throttle valves 68 and 69 is small, and a large amount of air-fuel mixture is sucked into the combustion chamber 318 via the main intake passage 63, so that Although the injection amount and injection force of Since the temperature of the inner wall of the fuel injection hole 318 also rises, the flame propagation speed increases and the combustibility improves even without generating swirl or turbulence, especially due to the jet flow from the injection holes 360.

In the above embodiment, if the distance X between the spark gap 334 and the injection hole 360 is too small, the injection chamber forming member 342 will be overheated and a hot spot will be formed, causing ignition. The effect is reduced, and after ignition, the flame injection chamber 3
56 is delayed, and the improvement in combustibility due to the jet flow is reduced.

Furthermore, if the amount of protrusion of the injection chamber forming member 342 into the main combustion chamber 318 is increased, the protruding end will become a hot spot and ignition will occur in this case as well, so it is better to make this amount of protrusion as small as possible. .

Furthermore, in the embodiment described above, the injection hole 360 is provided near the spark gap 334, and is located directly below the spark gap 334 and also on the spherical wall surface 3 of the cylinder head 312.
36, the fuel efficiency can be improved even if it is directed directly toward the spark gap 334 or in a direction slightly shifted from directly below the spark gap 334.

The engine configured as described above also exhibits the same effects as the first embodiment, and in the engine shown in the fourth embodiment, the lever ratio is changed as shown in the second embodiment and the engine is operated via the rondo. It is also possible to provide a throttle valve (,
Further, as shown in the third embodiment, the upstream end of the auxiliary intake passage may be opened to the discharge portion of the air supply pump as appropriate.

In addition, although the above embodiment shows the case of a gasoline engine with a carburetor, the same effect can be achieved even when the mixture is formed by a mixture forming device such as a fuel injection device, which is guided to the intake port. Furthermore, the fuel used is not limited to gasoline in any way, and even when other fuels such as LPG, kerosene, or diesel oil are used, the effects of improving combustibility and reducing fuel consumption can be obtained.

Furthermore, the type of engine is not limited to a four-stroke engine, and the spark gap of the ignition plug is faced into the combustion chamber, and near the spark gap, air and lean mixture are ,
It can be applied to an internal combustion engine provided with an injection hole for injecting gas such as exhaust gas.

[Brief explanation of the drawing]

FIG. 1 is a schematic explanatory diagram showing a first embodiment of the present invention, FIG. 2 is a view taken along the line A-A in FIG. 1, FIG. 3 is a view taken along line B-B in FIG. 1, and FIG. 1 is a sectional view taken along the line C-C in FIG. 1, FIG. 5 is a flow rate characteristic diagram of the sub-intake passage of the present invention, FIG. 8 is a schematic explanatory diagram showing a third embodiment of the present invention, FIG. 9 is a schematic explanatory diagram of an air supply pump applied to the third embodiment, and FIG. 11 is a perspective explanatory view showing the partition plate of the air feed pump cylinder, FIG. 12 is a discharge characteristic diagram of the air feed pump, and FIG. 13 is the fourth embodiment of the present invention. A schematic explanatory diagram showing an embodiment, FIG. 14 is an explanatory diagram taken along the arrow A-A in FIG. 13, and FIG. 15 is an explanatory diagram taken along the arrow 13-B in FIG. 13.
FIG. 16 is an explanatory view taken along arrow C in FIG. 13. 10.310; Engine body, 12,312; Cylinder head, 14,314; Cylinder block, 16,31
6; Piston, 18.318; Combustion chamber, 20,320
; Spark plug, 22,322; Main intake port, 24,3
24; Exhaust port, 26° 326: Main intake valve, 28,3
28; intake manifold, 30, 330; carburetor, 32,
332; Air cleaner, 34, 360; Injection hole, 36
．． 334; Spark gap, 38, 348; Sub-intake valve, 40° 350.354; Sub-intake passage, 41; Bypass passage, 6
3: Main intake passage, 66.67; Venturi, 68.69
; Throttle valve, 82; Pipe, 83; Orifice,
90; Control device; 94; Negative pressure chamber; 96; Intake system negative pressure passage; 98; Thermo valve; 100; Control valve;

Claims (1)

[Scope of Claims] 1. An injection hole that faces the spark gap of the ignition plug into the combustion chamber, is located near the spark gap, and injects gas such as air-lean mixture exhaust gas toward the vicinity of the spark gap. A main intake passage that supplies intake air to the combustion chamber via a main intake valve, a throttle valve provided in the main intake passage to control the intake air flow rate, and a main intake passage that communicates with the injection hole and that is connected to the injection hole. and a control valve that opens and closes the sub-intake passage and operates in conjunction with the throttle valve, and when the throttle valve opening is medium, the control valve is set to the maximum opening. An engine characterized in that it is configured to. 2. The engine according to claim 1, wherein a bypass passage is provided for the auxiliary intake passage, and a predetermined amount of gas is supplied to the auxiliary intake passage through the bypass passage when the control valve is fully closed. . 3. The engine according to claim 2, wherein the throttle valve of the main intake passage is a throttle valve of a carburetor that is provided in the main intake passage and supplies the air-fuel mixture to the main combustion chamber. 4. The engine according to claim 3, wherein the upstream end of the sub-intake passage opens upstream from the venturi portion of the carburetor. 5. The engine according to claim 3, wherein an upstream end of the sub-intake passage opens into a discharge portion of an air supply pump. 6. The engine according to claim 3, wherein the upstream end of the bypass passage opens upstream from the venturi section of the carburetor.