JP2003065053A - Compression self-ignition gasoline engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compression self-ignition gasoline engine capable of securing more preferable and suitable compression self-ignition property based on exhaust gas. SOLUTION: The direction of a valve sheet 24, in other words, the direction of opening of an exhaust valve 40 is set at the outer periphery direction of a combustion chamber 5 of an internal combustion engine 1 and the top surface direction of a piston 3. Thereby, in the opening of the exhaust valve 40, an exhaust gas that flows backward from an exhaust port 20 to the combustion chamber 5 becomes to flow along the outer periphery portion of the combustion chamber 5. The opening of the exhaust valve 40 is temporarily controlled through the closing of an inlet valve 30 being checked by a lift-amount sensor 60.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression self-ignition gasoline engine which performs compression self-ignition combustion by introducing exhaust gas into a combustion chamber of an engine (internal combustion engine).

[0002]

2. Description of the Related Art Conventionally, as a compression self-ignition gasoline engine of this type, there is one described in, for example, Japanese Patent Laid-Open No. 11-264319. As described in the publication, in this compression self-ignition engine, self-ignition combustion is usually performed based on the following mechanism. That is, first, the exhaust valve is opened during the intake stroke, and the backflow exhaust gas that flows backward from the exhaust port is flown in along the outer peripheral direction of the combustion chamber, so that the high-temperature backflow exhaust gas is mainly distributed in the outer peripheral region of the combustion chamber. To do so. By thus distributing the high-temperature backflow exhaust mainly in the outer peripheral region of the combustion chamber, a stratified distribution state in which the mixture of fuel and fresh air is mainly distributed in the central region of the combustion chamber. Then, when the backflow exhaust and the air-fuel mixture are compressed in the compression stroke that follows the intake stroke, the temperature of the high-temperature backflow exhaust is further increased by the adiabatic compression action, and finally the fuel distributed in the central region becomes The temperature reaches a temperature at which the air-fuel mixture with fresh air is self-ignited.

[0003]

By the way, in the above compression self-ignition gasoline engine, the exhaust valve is opened during the intake stroke, so that the exhaust gas recirculates into the intake pipe.
In the actual situation, it is difficult to form a mixture of pure fuel and fresh air in the central region of the combustion chamber. As a result, the air-fuel mixture in the combustion chamber is less likely to be in a stratified distribution state, which may lead to deterioration of combustion.

The present invention has been made in view of these circumstances, and an object thereof is to provide a compression self-ignition gasoline engine capable of ensuring a more preferable compression self-ignition property based on exhaust gas.

[0005]

[Means for Solving the Problems] Means for achieving the above-mentioned objects and their effects will be described below. According to the first aspect of the present invention, the backflow exhaust gas that flows back from the exhaust port is caused to flow into the outer peripheral portion of the combustion chamber where the mixture of fuel and fresh air is present, and the backflow exhaust gas is adiabatically compressed to perform compression self-ignition combustion. In the compression self-ignition gasoline engine to perform,
The gist of the present invention is to include means for temporarily opening the exhaust valve after the intake stroke of the engine to allow the backflow exhaust to flow into the combustion chamber.

According to the above construction, by temporarily opening the exhaust valve after the intake stroke, it is possible to avoid the problem that the backflow exhaust gas recirculates in the intake port, so that the central region of the combustion chamber is provided. It becomes possible to form a mixture of pure fuel and fresh air.

According to a second aspect of the present invention, in the first aspect of the present invention, the backflow exhaust is directed so as to flow along the outer peripheral direction of the combustion chamber and toward the upper surface of the piston of the engine. It is the gist to have means.

According to the above construction, the contact area between the mixture of fuel and fresh air and the exhaust gas flowing back can be increased,
The heat energy of the exhaust gas whose temperature has risen due to the adiabatic compression action can be sufficiently supplied to the air-fuel mixture. Therefore, stable self-ignition combustion can be performed.

According to a third aspect of the invention, in the second aspect of the invention, the directing means is provided with an exhaust port provided with a valve seat oriented in a tangential direction of an inner wall of a cylinder of the engine and in an upper surface direction of the piston. That is the summary.

According to the above structure, the structure described in claim 2 can be appropriately implemented. The invention according to claim 4 is
In the invention according to claim 2 or 3, fresh air flowing into the combustion chamber from an intake port in the intake stroke flows along an outer peripheral direction of the combustion chamber in a direction coincident with a directing direction of the backflow exhaust by the directing means. It is the gist to further provide a means for directing this.

According to the above construction, the exhaust gas that has flowed back into the combustion chamber due to the opening of the exhaust valve is made to accord with the flow of the air-fuel mixture that has flowed in from the intake port, and smoothly flows in along the outer peripheral direction of the combustion chamber. Can be made.

According to a fifth aspect of the present invention, in the second or third aspect of the invention, fresh air flowing into the combustion chamber from the intake port in the intake stroke opposes the directing direction of the backflow exhaust by the directing means. The gist of the present invention is to further include means for directing the gas to flow in along the outer peripheral direction of the combustion chamber.

According to the above construction, it is possible to make the backflow exhaust blow into the fresh air while hitting it against the fresh air.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) A first embodiment of a compression self-ignition gasoline engine according to the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing the overall configuration of a compression self-ignition gasoline engine according to this embodiment. As shown in FIG. 1, in the internal combustion engine 1, a combustion chamber 5 is defined by a cylinder head 1h, a cylinder block 1b, and a piston 3. An intake port 10 and an exhaust port 20 can communicate with the combustion chamber 5. An injector 11 connected to a fuel tank (not shown) is formed in the intake port 10, and fuel is injected into the intake port 10 with the valve opening operation of the injector 11. The mixture of fuel and intake air thus injected into the intake port 10 is supplied to the combustion chamber 5. A spark plug 7 is formed in the combustion chamber 5 to ignite the supplied mixture by spark ignition.
When the air-fuel mixture burns by being ignited by the spark plug 7, the combustion energy causes the piston 3 to move up and down on the wall surface of the cylinder block 1b. This piston 3
A crankshaft 9 is mechanically connected to
The combustion energy is extracted as the rotational force of the crankshaft 9.

The vertical movement of the piston 3 causes the combustion chamber 5 to move.
Between the intake port 10 and the combustion chamber 5 and the exhaust port 20.
It is carried out by selective communication between and disconnection control. Here, the communication between the combustion chamber 5 and the intake port 10 is controlled by an intake valve 30 which is an electromagnetically driven valve, and the communication between the combustion chamber 5 and the exhaust port 20 is controlled by an exhaust valve 40 which is an electromagnetically driven valve. It

Incidentally, each of the intake valve 30 and the exhaust valve 40 has an armature, and is electromagnetically driven by an electromagnetic force acting on the armature. Specifically, as shown in FIG. 3, the exhaust valve 4
Reference numeral 0 denotes a valve shaft 404, a valve body 402 provided at one end of the valve shaft 404, an electromagnetic drive unit 410 that reciprocates the valve shaft 404 in the cylinder head 1h, and a spring 420.
And 430.

Here, a valve seat 24 on which the valve body 402 is seated is formed at the periphery of the opening of the exhaust port 20 formed in the cylinder head 1h. That is, as the valve shaft 404 reciprocates, the valve body 402 moves to the valve seat 2
The exhaust port 20 is opened / closed by being seated / separated with respect to 4.

On the other hand, the electromagnetic drive unit 410 is connected to the valve shaft 40.
Armature 414 fixed to 4 and this armature 4
A lower core 416e and an upper core 418e arranged so as to sandwich 14 are provided. Where armature 4
14 is made of a high magnetic permeability material formed in a disc shape. The lower core 416e and the upper core 418e each have a high magnetic permeability material formed in an annular shape, and the valve shaft 404 is reciprocally inserted through the central portion thereof.

An annular groove 416h centered on the axial center of the valve shaft 404 is formed on the surface of the lower core 416e facing the armature 414, and an annular lower coil 416c is provided in the groove 416h. ing. With the lower coil 416c and the lower core 416e,
An electromagnet (opening drive electromagnet) 416 that drives the valve body 402 in the valve opening direction is configured.

On the other hand, an annular groove 418h centered on the axis of the valve shaft 404 is formed on the surface of the upper core 418e facing the armature 414, and an annular upper coil 418c is arranged in the groove 418h. ing.
The upper coil 418c and the upper core 418e constitute an electromagnet (close driving electromagnet) 418 for driving the valve body 2 in the valve closing direction.

Further, the valve body 4 formed by the electromagnetic drive unit 410
In order to smoothly perform the opening / closing operation of 02, a spring for urging the valve body 402 in its opening direction and closing direction is provided. That is, the lower retainer 422 is provided in a portion of the valve shaft 404 located between the lower core 416e and the cylinder head 420, and the lower spring 420 is arranged in a compressed state between the lower retainer 422 and the cylinder head 1h. There is. The valve body 402 is biased in the valve closing direction by the elastic force (biasing force) of the lower spring 420. On the other hand, at the end of the valve shaft 404 opposite to the valve body 402, that is, at a portion located above the upper core 418e, an upper retainer 432 is provided, and the upper retainer 432 and the electromagnetic drive unit 410 are not shown. The upper spring 430 is arranged in a compressed state between the upper spring 430 and the upper cap 434 provided in the casing. The valve body 402 is biased in the valve opening direction by the elastic force (biasing force) of the upper spring 430.

Note that FIG. 3 shows the state of the valve body 402 when no electromagnetic force is generated in any of the electromagnets 416 and 418. In this state, the armature 414 is
A position where the elastic forces of the springs 420 and 430 are balanced without being attracted by the electromagnetic force of the electromagnets 416 and 418, that is, the lower core 416e and the upper core 4
It stands still at a position approximately midway between 18e.

An electromagnet 416 is attached to the armature 414.
When the electromagnetic force of the electromagnet 418 is exerted on the armature 414, the armature 414 is attracted to the lower core 416e side or the upper core 418e side. This electromagnetic force is generated by these electromagnets 416, 41.
It is generated by energizing each of the eight coils 416c and 418c.

In this embodiment, the electromagnets 416,
Control of energization to each coil 416c, 418c of 418
This is performed based on the displacement of the exhaust valve 40 (valve element 402, valve shaft 404). In order to detect this displacement, the lift amount sensor 60 is provided in the upper cap 434 in this embodiment. The lift amount sensor 60 outputs a voltage (detection signal) that changes according to the distance between the sensor 60 and the upper retainer 432. Based on this voltage, the amount of displacement of the upper retainer 432, in other words, For example, the amount of displacement of the valve body 402 can be detected.
Then, by using the detection result of the lift amount sensor 60, the energization control can be performed based on the displacement of the exhaust valve 40. The lift amount sensor 60 is also provided in the intake valve 30, and the lift amount sensor 60 shown in FIG.

This energization control is performed by the electronic control unit 50 shown in FIG. 1 which generally controls various internal combustion engines. The electronic control unit 50 includes a CPU, a memory, a drive circuit that supplies an exciting current to the coils 416c and 418c of the electromagnets 416 and 418, an input circuit that receives the detection signal of the lift amount sensor 60, and the detection signal to A /
An A / D converter (not shown) for D conversion is provided.

The electronic control unit 50 not only controls the intake valve 30 and the exhaust valve 40 based on the lift value detected by the lift amount sensor 60, but also controls the intake valve 30 based on the operating state of the internal combustion engine 1. Also, the valve characteristics of the exhaust valve 40 are appropriately controlled. Specifically, the detection results of an air flow meter 62 that detects the amount of intake air flowing through the intake port 10 and a crank angle sensor 64 that detects the rotation mode of the crankshaft 9 are input as input signals, and based on these, the valve characteristics described above are obtained. To control properly. Particularly, in the present embodiment, the control for causing the exhaust gas discharged to the exhaust port 20 to flow back to the outer peripheral portion of the combustion chamber 5 in order to perform the compression self-ignition combustion in the low and medium load regions and the low and medium rotation speed regions of the internal combustion engine 1. To do.

By the way, when the exhaust gas discharged to the exhaust port 20 is made to flow backward to the outer peripheral portion of the combustion chamber 5, a stratified distribution state in which a mixture of fuel and fresh air is formed near the center of the combustion chamber 5. It is as described above that it may be difficult to become. Therefore, in the present embodiment, the exhaust valve 40 is temporarily opened after the intake stroke to allow the backflow exhaust to flow into the combustion chamber 5. That is, when the electronic control unit 50 determines that the intake valve 30 is closed by the detection signal of the lift amount sensor 60, the electronic control unit 50 temporarily opens the exhaust valve 40.

In this way, by causing the backflow exhaust to flow into the combustion chamber 5 after the intake stroke, this backflow exhaust is introduced into the intake port 1
It is possible to form a mixture of pure fuel and fresh air in the central portion of the combustion chamber 5 while avoiding the problem of recirculation into zero. Therefore, the compression self-ignitability can be improved.

FIG. 2 shows the intake valve 3 according to this embodiment.
0 and the control mode of the exhaust valve 40 are illustrated. As shown in FIG. 2, while the exhaust valve 40 is temporarily opened after the intake stroke, the valve characteristics such as the lift amount and the working angle thereof are variably controlled according to the operating state, so that the reverse flow into the combustion chamber 5 occurs. The amount of exhaust gas can be adjusted.

Further, in this embodiment, as shown in FIG. 4, the backflow exhaust is directed so as to flow in along the outer peripheral direction of the combustion chamber 5 and toward the upper surface of the piston 3. By making the exhaust gas flow backward in this way, the contact area between the mixture of fuel and fresh air and the exhaust gas that flows backward can be increased, and the thermal energy of the exhaust gas whose temperature has risen due to the adiabatic compression action can be sufficiently supplied to the gas mixture. You will be able to. Therefore, stable self-ignition combustion can be performed.

Specifically, in this embodiment, as shown in FIG. 5, the valve element 402 of the exhaust valve 40 is closed when the valve is closed.
The valve seat 24 on which the
The direction is tangential to the inner wall and toward the upper surface of the piston 3.
That is, the normal direction of the opening surface of the exhaust port 20 to the combustion chamber 5 is the tangential direction of the inner wall of the cylinder block 1b and the upper surface direction of the piston 3. In other words, the valve opening direction of the exhaust valve 40 is the tangential direction of the inner wall of the cylinder block 1b and the upper surface direction of the piston 3.

Further, in this embodiment, the air-fuel mixture flowing from the intake port 10 into the combustion chamber 5 in the intake stroke is allowed to flow along the outer peripheral direction of the combustion chamber 5 in the same direction as the direction of the backflow exhaust. To do. Specifically, as shown in FIG. 5, the valve seat 14 is oriented in the tangential direction of the inner wall of the cylinder block 1b and in the direction of the outer peripheral component of the combustion chamber 5 in the valve opening direction of the exhaust valve 40. In other words, the valve opening direction of the intake valve 30 is the direction tangential to the inner wall of the cylinder block 1b and the direction that coincides with the outer peripheral direction component of the combustion chamber 5 in the valve opening direction of the exhaust valve 40. As a result, the exhaust gas that flows back into the combustion chamber 5 with the opening of the exhaust valve 40 follows the flow of the air-fuel mixture that has flowed in from the intake port 10,
It smoothly flows along the outer peripheral direction of the combustion chamber 5.

The arrangement of the valve seats 14 and 24, and further the setting of the opening directions of the intake valve 30 and the exhaust valve 40 are made suitable for the compression self-ignition combustion because these valves are electromagnetically driven valves. It is possible to do it freely. On the other hand, when opening and closing these valves by using the camshaft to drive the engine, there is usually a restriction on the setting of the opening direction of each valve in order to match the opening and closing direction with the rotation direction of the camshaft. Will be accompanied.

In this embodiment, as shown in FIG. 5, two exhaust valves 40 are provided for one cylinder, and the valve diameters of these exhaust valves 40 are set to be different from each other. As a result, the amount of backflow exhaust can be adjusted by selecting which exhaust valve 40 to open after the intake stroke according to the operating state of the internal combustion engine 1.

In this embodiment described above, the following effects can be obtained. (1) During compression self-ignition operation, exhaust valve 4 after intake stroke
0 was opened temporarily. As a result, it is possible to avoid the problem that the backflow exhaust gas recirculates in the intake port 10, and it is possible to form a mixture of pure fuel and fresh air in the central region of the combustion chamber 5.

(2) The exhaust gas flowing back into the combustion chamber 5 is directed so as to flow along the outer peripheral direction of the combustion chamber 5 and toward the upper surface of the piston 3. By allowing the backflow exhaust to flow in this way, the contact area between the mixture of fuel and fresh air and the backflow exhaust can be increased, and the thermal energy of the exhaust gas whose temperature has risen due to the adiabatic compression action is sufficiently supplied to the air mixture. You will be able to. Therefore, stable self-ignition combustion can be performed.

(3) Since the electromagnetically driven valve is applied to the intake valve 30 and the exhaust valve 40, the opening directions of the intake valve 30 and the exhaust valve 40 can be freely set. (4) In the intake stroke, the air-fuel mixture flowing from the intake port 10 into the combustion chamber 5 is allowed to flow along the outer circumferential direction of the combustion chamber 5 in the direction of the backflow exhaust. As a result, the backflow exhaust flowing into the combustion chamber 5 with the opening of the exhaust valve 40 is made to follow the flow of the air-fuel mixture flowing from the intake port 10 and smoothly flow along the outer peripheral direction of the combustion chamber 5. You can

(Second Embodiment) A second embodiment of the compression self-ignition gasoline engine according to the present invention will be described below with reference to the drawings, focusing on the differences from the first embodiment.

In the first embodiment described above, the air-fuel mixture flowing from the intake port 10 into the combustion chamber 5 in the intake stroke is allowed to flow along the outer circumferential direction of the combustion chamber 5 in the same direction as the backflow exhaust gas. . On the other hand, in the present embodiment, the air-fuel mixture flowing from the intake port 10 into the combustion chamber 5 in the intake stroke is allowed to flow in the outer circumferential direction of the combustion chamber 5 while facing the direction of the backflow exhaust. As a result, the backflow exhaust flowing into the combustion chamber 5 when the exhaust valve 40 is opened can be made to hit below the mixture while hitting the mixture flowing from the intake port 10.

In order to direct the air-fuel mixture flowing into the combustion chamber 5 in this way, as shown in FIG. 6, the valve seat is provided in the tangential direction of the outer periphery of the combustion chamber 5 and the exhaust valve 40 is opened. It suffices to direct it in a direction facing the outer peripheral component of the combustion chamber 5 in the valve direction. In other words, the valve opening direction of the intake valve 30 may be set to a direction that is tangential to the outer circumference of the combustion chamber 5 and that faces the outer circumferential component of the combustion chamber 5 in the valve opening direction of the exhaust valve 40.

According to this embodiment described above, in addition to the effects (1) to (3) of the first embodiment,
Further, the following effects can be obtained. (5) The backflow exhaust is mixed by directing the air-fuel mixture flowing from the intake port 10 into the combustion chamber 5 in the intake stroke so as to face the direction of the backflow exhaust and flow in along the outer peripheral direction of the combustion chamber 5. You can sneak under it while hitting your mind.

(Third Embodiment) Hereinafter, a third embodiment of the compression self-ignition gasoline engine according to the present invention will be described with reference to the drawings, focusing on the differences from the first embodiment.

In the first embodiment, two cylinders are provided.
Two exhaust valves 40 were provided, and the tangential components of the combustion chamber 5 in the opening / closing direction of these exhaust valves 40 were opposed to each other. At this time, when one of the exhaust valves 40 is opened at the time of opening the valve after the intake stroke, there is no influence on the flow of exhaust gas flowing backward. However, when both exhaust valves 40 are opened at the time of opening the valve after the intake stroke, the exhaust flows that flow back to the combustion chamber 5 due to the opening of each exhaust valve 40 oppose each other, so that the combustion chamber 5 This will impede the flow of backflow exhaust along the outer peripheral direction.

Therefore, in this embodiment, as shown in FIG. 7, the valve seats 24 are arranged so as to face in a direction substantially coincident with each other. In other words, the tangential components of the combustion chamber 5 in the opening / closing direction of each exhaust valve 40 are made to coincide with each other. Thus, even when both exhaust valves 40 are opened, the exhaust gas that flows back into the combustion chamber 5 due to the opening of these valves can be recirculated along the outer peripheral portion of the combustion chamber 5.

Further, in the present embodiment, the air-fuel mixture flowing from the intake port 10 into the combustion chamber 5 in the intake stroke is allowed to flow in the outer peripheral direction of the combustion chamber 5 so as to face the direction of the backflow exhaust.

In this way, the inflow direction of the fresh air flowing from the intake port 10 along the outer peripheral direction of the combustion chamber 5 in the intake stroke is made to oppose the outer peripheral component of the combustion chamber 5 in the backflow direction of the exhaust gas. Then, it is possible to make the backflow exhaust hit the air-fuel mixture and squeeze it under it.

According to the present embodiment described above, in addition to the effects (1) to (3) of the first embodiment and the effect (5) of the second embodiment, Further, the following effects can be obtained.

(6) Since the tangential direction components of the combustion chamber 5 in the opening / closing direction of each exhaust valve 40 are made to coincide with each other, even if both exhaust valves 40 are opened, they are accompanied by opening. Exhaust gas that flows back into the combustion chamber 5
It is possible to recirculate along the outer peripheral portion of the combustion chamber 5.

The above-described embodiments may be modified and implemented as follows. In the third embodiment, the air-fuel mixture that flows into the combustion chamber 5 from the intake port 10 in the intake stroke may flow along the outer circumferential direction of the combustion chamber 5 so as to match the direction of the backflow exhaust. .

Instead of disposing the valve seat in the outer peripheral direction of the combustion chamber 5 and in the upper surface direction of the piston, the vicinity of the opening of the exhaust port 20 may be set as the outer peripheral direction of the combustion chamber 5. This allows the exhaust gas to flow backward along the outer peripheral direction of the combustion chamber 5 after the intake stroke.

The intake valve and exhaust valve are not limited to electromagnetically driven valves. Even in an engine-driven exhaust valve using a cam provided on a camshaft, for example, Japanese Patent Laid-Open No. 2001-0
The exhaust valve can be opened after the intake stroke by adopting a configuration conforming to the configuration described in Japanese Patent Publication No. 98963. That is, the cam that drives the exhaust valve has a main cam mountain that mainly opens the valve, and an auxiliary cam mountain that auxiliaryly opens the valve during a period other than the valve opening period by the main cam mountain. It is assumed to have. Then, the formation position of the auxiliary cam ridge may be such that the exhaust valve can be opened after the intake stroke. Here, the height of the auxiliary cam peak is formed as a three-dimensional cam that continuously changes in the axial direction of the cam, and the cam shaft provided with the cam is displaced in the axial direction so that the auxiliary cam peak causes the valve lift. The amount may be adjusted. This allows
By displacing the camshaft in its axial direction, the amount of backflow exhaust can be adjusted.

Not limited to the intake port injection type internal combustion engine,
The present invention may be applied to a cylinder injection type internal combustion engine.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a first embodiment of a compression self-ignition gasoline engine according to the present invention.

FIG. 2 is a time chart showing an example of valve characteristics of the same embodiment.

FIG. 3 is a cross-sectional view showing a configuration of an electromagnetically driven valve of the same embodiment.

FIG. 4 is a diagram showing a backflow mode of exhaust gas of the same embodiment.

FIG. 5 is a diagram schematically showing the arrangement of intake valves and exhaust valves of the same embodiment.

FIG. 6 is a diagram schematically showing the arrangement of intake valves and exhaust valves of the second embodiment of the compression self-ignition gasoline engine according to the present invention.

FIG. 7 is a diagram schematically showing the arrangement of intake valves and exhaust valves in the third embodiment of the compression self-ignition gasoline engine according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 1b ... Cylinder block, 1h ... Cylinder head, 2 ... Valve body, 3 ... Piston, 5 ... Combustion chamber, 7 ...
Spark plug, 9 ... crankshaft, 10 ... intake port, 11 ... injector, 20 ... exhaust port, 14, 2
4 ... Valve seat, 30 ... Intake valve, 40 ... Exhaust valve, 50 ... Electronic control unit, 60 ... Lift amount sensor, 62
... Air flow meter, 64 ... Crank angle sensor, 402
... Valve element, 404 ... Valve shaft, 410 ... Electromagnetic drive unit, 414 ...
Armatures, 416, 418 ... Electromagnets, 416c, 41
8c ... lower coil, 416e, 418e ... lower core, 4
16h, 418h ... Groove, 420 ... Lower spring, 42
2 ... Lower retainer, 430 ... Upper spring, 432
... Appalitena, 434 ... Upper cap.

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Claims (5)

[Claims] 1. A backflow exhaust gas that flows back from an exhaust port is caused to flow into an outer peripheral portion of a combustion chamber where a mixture of fuel and fresh air exists.
In a compression self-ignition gasoline engine that performs compression self-ignition combustion by adiabatically compressing this backflow exhaust, a means for causing the backflow exhaust to flow into the combustion chamber by temporarily opening the exhaust valve after the intake stroke of the engine is provided. A compression self-ignition gasoline engine characterized by comprising. 2. The compression self-ignition gasoline engine according to claim 1, further comprising a directing means for directing the backflow exhaust so as to flow in along an outer peripheral direction of the combustion chamber and toward an upper surface of a piston of the engine. A compression self-ignition gasoline engine characterized by comprising. 3. The exhaust port including a valve seat, which is directed in a tangential direction of a cylinder inner wall of the engine and in a direction of an upper surface of the piston.
The described compressed self-ignition gasoline engine. 4. The compression self-ignition gasoline engine according to claim 2, wherein the fresh air flowing into the combustion chamber from the intake port in the intake stroke coincides with the directing direction of the backflow exhaust by the directing means. A compression self-ignition gasoline engine, further comprising means for directing the combustion chamber to flow in along the outer peripheral direction thereof. 5. The compression self-ignition gasoline engine according to claim 2 or 3, wherein fresh air flowing into the combustion chamber from an intake port in the intake stroke is opposed to the directing direction of the backflow exhaust by the directing means. A compression self-ignition gasoline engine, further comprising means for directing the combustion chamber to flow in along the outer peripheral direction thereof.