JP2010031687A - Spark ignition internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spark ignition internal combustion engine improving charging efficiency and anti-knocking performance by scavenging burned gas while inhibiting fresh air from blowing by. <P>SOLUTION: The spark ignition internal combustion engine includes a supercharger. An intake valves 6 is disposed at one side and a pair of exhaust valves 7, 7 are disposed at another with a straight line (c) passing on a cylinder axis line A of a combustion chamber 5 and in parallel with a crankshaft in a view of the cylinder axis line A direction put therebetween. An intake valve 33 for scavenging is disposed at a section further from a cylinder axis line A than a straight line (a) connecting a center of each exhaust valve 7. The intake valve 33 for scavenging closes later than close timing of the exhaust valves 7 at least in a supercharged operation zone. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a spark ignition internal combustion engine including a supercharger that compresses air and supplies the compressed air to a combustion chamber.

As an internal combustion engine equipped with this type of supercharger, for example, in Patent Document 1, supercharging is performed so that the pressure of the intake passage is higher than the pressure of the exhaust passage during the overlap period during low-load operation. Things have been proposed.
Japanese Patent Laid-Open No. 10-274069

  By the way, in the conventional internal combustion engine, since supercharging is performed so that the pressure in the intake pipe becomes higher than the exhaust pressure, a part of fresh air is discharged to the exhaust passage without being used for combustion in the overlap period. There is. Since the fresh air blown into the exhaust passage contains fuel and surplus oxygen, the heat load of the catalyst is increased and the fuel consumption is deteriorated. For this reason, it is not possible to provide a sufficient overlap period, which is a limitation in improving output performance. Further, if the overlap period is shortened, the burnt gas is not sufficiently discharged, resulting in a decrease in filling efficiency and a problem that the anti-knocking performance is lowered due to the high-temperature burned gas remaining in the cylinder. .

  The present invention has been made in view of the above-described conventional situation, and provides a spark ignition internal combustion engine capable of improving charging efficiency and anti-knocking performance by scavenging burnt gas while suppressing blow-through of fresh air. The issue is to provide.

  The invention of claim 1 is a spark ignition type internal combustion engine provided with a supercharger that compresses air and supplies the compressed air to the combustion chamber. When viewed in the cylinder axis direction, the combustion chamber passes through the cylinder axis. An intake valve is arranged on one side across a straight line parallel to the crankshaft, and a pair of exhaust valves are arranged on the other side. A scavenging exhaust valve is located at a position farther from the cylinder axis than a straight line connecting the centers of the exhaust valves. The scavenging exhaust valve is closed after the exhaust valve at least in the supercharging operation region.

  According to a second aspect of the present invention, in the spark ignition internal combustion engine according to the first aspect, the intake valve is disposed at a position substantially opposite to the scavenging exhaust valve across a cylinder axis. .

  According to a third aspect of the present invention, in the spark ignition internal combustion engine according to the first aspect of the present invention, the spark-ignition internal combustion engine further includes an exhaust variable valve timing mechanism that varies an opening / closing timing of the scavenging exhaust valve. The exhaust valve is characterized in that the closing timing in the non-supercharging operation region is earlier than the closing timing in the supercharging operation region.

  According to a fourth aspect of the present invention, the spark ignition type internal combustion engine according to the first aspect further includes an intake variable valve timing mechanism that makes an opening / closing timing of the intake valve variable. It is characterized in that the opening time in the supercharging operation region is made earlier than the opening time in the non-supercharging operation region.

  According to a fifth aspect of the present invention, in the spark ignition type internal combustion engine according to any one of the first to fourth aspects, an intake control valve is disposed in an intake passage where the supercharger is disposed, and the intake A bypass passage for bypassing the control valve is provided, and a downstream end opening of the bypass passage is arranged to be directed to a gap between the intake valve and the intake opening.

  According to the internal combustion engine of the first aspect of the present invention, the scavenging exhaust valve is disposed at a position farther from the cylinder axis than the straight line connecting the centers of the exhaust valves, and the scavenging exhaust valve is delayed from the exhaust valve in the supercharging operation region. As a result, the scavenging exhaust valve located farthest from the intake valve closes behind the exhaust valve, and the burned gas is efficiently scavenged while suppressing the discharge of fresh air. be able to. As a result, the charging efficiency can be improved, an excessive temperature rise of the compressed mixture can be suppressed, the anti-knocking performance can be improved, and the output performance can be improved.

  Furthermore, since it becomes possible to operate with an appropriate ignition timing, the exhaust gas temperature can be lowered accordingly, the heat load on the catalyst can be reduced, and the reliability through quality can be improved.

  Here, when scavenging the burned gas, it is conceivable to provide a scavenging intake valve outside the pair of intake valves. In this case, for example, if the fuel is injected and supplied from one fuel injection valve, the distance between the fuel injection valve and each intake valve is increased, so that the amount of fuel adhering to the wall surface is reduced. There is a concern that the combustion efficiency will increase and the combustion efficiency will decrease. In order to reduce the fuel adhesion amount, a fuel injection valve is disposed in each intake valve. However, the cost increases accordingly, which is not preferable as an industrial product.

  In the present invention, since the scavenging exhaust valve is arranged outside the cylinder axis from the exhaust valve, problems such as when the scavenging valve is provided on the intake side can be avoided.

  In the invention of claim 2, since the intake valve is disposed at a position substantially opposite to the scavenging exhaust valve, it is possible to efficiently scavenge the burned gas while suppressing the discharge of fresh air. In the supercharging operation region, the pressure in the intake passage is higher than the pressure in the cylinder during the period in which the scavenging exhaust valve and the intake valve overlap, and at this time, the piston is positioned near the top dead center. Therefore, by arranging the scavenging exhaust valve and the intake valve as far apart as possible, fresh air is pushed into the cylinder by the pressure, and the burnt gas is more easily pushed out of the cylinder than the inertia when the piston rises. Burned gas can be efficiently scavenged while suppressing the outflow of fresh air.

  In the invention of claim 3, since the closing timing in the non-supercharging operation region of the scavenging exhaust valve is made earlier than the closing timing in the supercharging operation region, the overlap period between the scavenging exhaust valve and the intake valve is shortened. It is possible to suppress the backflow of burned gas and to prevent the combustion from becoming unstable.

  That is, as described above, the operation region where scavenging is performed is a supercharging operation region in which the pressure in the intake passage is higher than the pressure in the cylinder, and under such operation conditions, by providing a sufficient overlap period, The burned gas in the cylinder can be scavenged efficiently. However, at the valve timing at which scavenging is performed, an excessive amount of burned gas flows backward from the scavenging exhaust valve to the intake passage, particularly in an extremely low load range including idling, and combustion tends to become unstable, and in some cases, misfire may occur. There is. In order to prevent such a backflow of burnt gas, in the non-supercharging operation region, control is performed to reduce the overlap period by increasing the timing for closing the scavenging exhaust valve. In this case, the structure of the variable valve timing mechanism can be simplified by driving the scavenging exhaust valve and the exhaust valve with a single camshaft, which is advantageous in terms of cost.

  In the fourth aspect of the invention, in the supercharging operation region, the intake valve is opened earlier than the opening timing at the time of non-supercharging operation, so that a necessary overlap period can be secured, and the fresh air charging efficiency by scavenging In addition, the knock resistance can be improved, and good flame propagation can be maintained.

  According to the invention of claim 5, an intake control valve is provided in the intake passage, and a bypass passage for bypassing the intake control valve is provided, and an intake vortex of a horizontal vortex or a vertical vortex is generated in the combustion chamber by the bypass passage. Therefore, stable combustion can be performed without providing an excessive overlap period. That is, it is effective to increase the overlap period in order to fully exhibit the effect during the supercharging operation. However, if the overlap period is simply increased, in the partial load operation region, deterioration of combustion due to an increase in burned gas tends to occur. For example, even when a variable valve timing mechanism is used, it is necessary to increase the variable range of valve timing, and control delay is likely to occur.

  In the present invention, since a bypass passage for bypassing the intake passage is provided, a horizontal vortex and a vertical vortex intake vortex are generated in the combustion chamber, so that sufficient mixing and strong turbulence of the compressed air-fuel mixture immediately before ignition is obtained. And efficient rapid combustion can be performed. Thereby, combustion in a low load operation region can be stabilized without providing an excessive overlap period, the variable valve timing mechanism can be simplified, and control responsiveness can be improved. In the present invention, it goes without saying that combustion can be stabilized even when the overlap period is increased.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  1 to 5 are views for explaining a spark ignition internal combustion engine equipped with a supercharger according to a first embodiment of the present invention. FIG. 1 is a schematic configuration diagram of the spark ignition internal combustion engine, FIG. Is a cross-sectional view of an internal combustion engine, FIG. 3 is a cross-sectional view of a cylinder head of the internal combustion engine, FIG. 4 is a cross-sectional plan view of the cylinder head, and FIGS. 5 (a) and 5 (b) are an intake valve, an exhaust valve, and a scavenging exhaust valve. It is an opening / closing timing diagram.

  In the figure, reference numeral 1 denotes a four-cycle multi-cylinder spark ignition internal combustion engine. The internal combustion engine 1 has a cylinder block 2 in which four cylinder bores (cylinders) 2a are formed connected to a cylinder head 3 in which four combustion recesses 3a are formed so as to face the cylinder bores 2a. The piston 4 has a schematic structure in which it is slidably inserted.

  A combustion chamber 5 is formed by a space surrounded by the cylinder bore 2 a, the combustion recess 3 a and the top surface of the piston 4. The piston 4 is connected to a crankshaft (not shown) by a connecting rod 4a.

  Each combustion recess 3 a of the cylinder head 3 is formed with one intake opening 3 b communicating with the combustion chamber 5 and two exhaust openings 3 c and 3 c. When viewed in the cylinder axis direction, the intake opening 3b passes through the cylinder axis A and is disposed on one side across a straight line c parallel to the crankshaft. Each exhaust opening 3c is located on the other side across the straight line c. Is arranged.

  An intake valve 6 and exhaust valves 7 and 7 are disposed in the intake opening 3b and the exhaust openings 3c, respectively. The intake valve 6 is driven by an intake cam shaft 8 and each exhaust valve 7 is driven to open and close by an exhaust cam shaft 9. Is done.

  Three first to third spark plugs 10a to 10c are mounted on each cylinder bore 2a of the cylinder head 3 so as to face the combustion recess 3a. The first spark plug 10a is disposed substantially at the center of the cylinder bore 2a and slightly displaced from the straight line c toward the exhaust valve 7. The second and third spark plugs 10b, 10c It is arranged outside and slightly displaced from the straight line c toward the intake valve 6 side.

  The intake opening 3b is led to one side wall of the cylinder head 3 by an intake port 3d, and each exhaust opening 3c is led to the other side wall of the cylinder head 3 by one exhaust port 3e.

  An exhaust pipe 13 is connected to each exhaust port 3e. An exhaust merging pipe 14 common to each cylinder is connected to the downstream end of each exhaust pipe 13, and a muffler 15 is connected to the downstream end of the exhaust merging pipe 14. A catalyst 16 for purifying exhaust gas is interposed in the middle of the exhaust merging pipe 14.

  An intake pipe 17 is connected to each intake port 3d. A surge tank 18 common to each cylinder is connected to the upstream end of each intake pipe 17. An intake merging pipe 19 is connected to the surge tank 18, and an air cleaner 20 for filtering air is connected to the upstream end of the intake merging pipe 19.

  A throttle valve 21 common to each cylinder is disposed at the downstream end of the intake merging pipe 19. The throttle valve 21 is disposed in the vicinity of the connection portion of the surge tank 18 of the intake merging pipe 19.

  Each intake pipe 17 is provided with an intake control valve 22. Each intake control valve 22 is connected by a single valve shaft 22a, and is integrally opened and closed by a drive motor 23 connected to the valve shaft 22a. The intake control valve 22 is disposed near the connection portion of the surge tank 18 at the upstream end of the intake pipe 17. Thus, the passage volume from the intake valve 6 to the intake control valve 22 of the intake pipe 17 is increased.

  A fuel injection valve 25 is mounted on the downstream end of each intake pipe 17 so as to face the axial center of the intake port 3d. The fuel injection valve 25 is arranged to inject fuel toward the center of the back of the intake valve 6.

  The internal combustion engine 1 includes a supercharger 26 that compresses air from the air cleaner 20 and supplies the compressed air to the combustion chamber 5.

  The supercharger 26 includes a turbine 27 that is provided to extend over the exhaust merging pipe 14 and the intake merging pipe 19, and an intercooler 28 that is provided to the intake merging pipe 19.

  The turbine 27 is rotationally driven by the exhaust gas flowing through the exhaust merging pipe 14, and the air from the air cleaner 20 is compressed by the rotation of the turbine 27. The compressed air is cooled by the intercooler 28 and introduced into the surge tank 18, and is supplied from the surge tank 18 through the intake pipe 17 to the combustion chamber 5.

  The internal combustion engine 1 includes an EGR device 40 that recirculates a part of the exhaust gas to the combustion chamber 5 and reburns it.

  The EGR device 40 includes an EGR introduction pipe 41 connected to the upstream side of the turbine 27 of the exhaust merging pipe 14, an EGR cooler 42 interposed in the middle of the EGR introduction pipe 41, and the EGR introduction pipe 41. The EGR control valve 43 provided on the downstream side of the EGR cooler 42 and the fine particles provided on the upstream side of the EGR cooler 42 of the EGR introduction pipe 41 to remove carbon and other fine particles mixed in the EGR gas. And a trap 44.

  The downstream end introduction port 41 a of the EGR introduction pipe 41 is connected to the downstream side of the throttle valve 21 of the intake merging pipe 19. Further, an EGR check valve 45 for controlling the amount of EGR gas introduced is interposed in the vicinity of the upstream side of the inlet 41a of the EGR introduction pipe 41. The EGR check valve 45 allows only the flow of EGR gas to the surge tank 18 and blocks the flow in the reverse direction. The EGR check valve 45 is not always necessary when the downstream end inlet 41a is connected downstream of the throttle.

  The internal combustion engine 1 includes a bypass passage 30 disposed in each intake pipe 17 so as to bypass the intake control valve 22, and an intake check valve 31 interposed in each bypass passage 30.

  Each of the bypass passages 30 directs and ejects the intake air so that a horizontal vortex or vertical vortex air flow is generated in the cylinder bore 2a when the intake control valve 22 is fully closed. It is formed along this side.

  The downstream end 30 a of each bypass passage 30 is connected to the downstream end of the intake port 3 d, and the upstream end 30 b is connected to the surge tank 16.

  The intake check valve 31 is a reed valve type that allows only the flow of intake air to the cylinder side and blocks the reverse flow, and is disposed in the vicinity of the connection portion of the surge tank 18 at the upstream end 30b. Has been.

  A scavenging opening 3 f that communicates the exhaust port 3 e and the combustion chamber 5 is formed in the combustion recess 3 a of the cylinder head 3. The scavenging opening 3f is provided with a scavenging exhaust valve 33. The scavenging exhaust valve 33 is driven to open and close together with the exhaust valve 7 by the exhaust camshaft 9.

  The scavenging exhaust valve 33 is located between the exhaust valves 7 and 7 and at a position further away from the cylinder axis A than the straight line a connecting the centers of the exhaust valves 7, that is, outward in the direction perpendicular to the crankshaft. Are arranged (see FIG. 4). The scavenging exhaust valve 33 is disposed at a position facing the intake valve 6 in the direction perpendicular to the crankshaft. Accordingly, the scavenging exhaust valve 33 is disposed at a position farthest from the intake valve 6.

  The downstream end of the bypass passage 30 is branched into left and right passages 30a and 30a. The left and right passages 30a and 30a pass through the valve shaft of the intake valve 6 to the left and right, and the intake opening of the intake valve 6 It is directed to the valve gap s in the inner part of the valve gap s with 3a near the straight line c.

  The internal combustion engine 1 includes a variable valve turning mechanism 35 that changes the opening / closing timing of the intake valve 6, the exhaust valve 7, and the scavenging exhaust valve 33.

  The variable valve timing mechanism 35 includes an intake side actuator 36 that continuously changes the opening / closing timing of the intake valve 6 via the intake cam shaft 8, and each exhaust valve 7 and scavenging exhaust via the exhaust cam shaft 9. An exhaust side actuator 37 that continuously changes the opening and closing timing of the valve 33 and an ECU 38 that controls the actuators 36 and 37 according to the operating state are provided. The ECU 38 controls the intake side actuator 36 and the exhaust side actuator 37 as follows.

The intake valve 6 opens substantially at the top dead center in the non-supercharged operation region at the time of extremely low negative including idling (see FIG. 5A), whereas in the supercharged operation region, for example, before the top dead center. It opens at 32 ° (see FIG. 5B). That is, the opening timing of the intake valve 6 in the supercharging operation region is controlled to be earlier than the opening timing of the non-supercharging operation region.

  The scavenging exhaust valve 33 closes at 6 ° after top dead center in the non-supercharged operation region (see FIG. 6A), for example, and closes at 32 ° after top dead center in the supercharged operation region. (See (b) of the figure). That is, the closing timing of the scavenging exhaust valve 33 in the non-supercharging operation region is controlled to be earlier than the closing timing in the supercharging operation region.

  Furthermore, the exhaust valve 7 closes at, for example, 20 ° before top dead center in the non-supercharged operation region (see FIG. 5A), while in the supercharged operation region, for example, at 6 ° after top dead center. Close (see (b) of the figure). That is, the closing timing of the exhaust valve 7 in the non-supercharging operation region is controlled to be earlier than the closing timing in the supercharging operation region.

  The scavenging exhaust valve 33 is controlled to close later than the exhaust valve 7 in both the non-supercharging operation region and the supercharging operation region. Since the exhaust valve 7 and the scavenging exhaust valve 33 are controlled by a common valve timing mechanism, they are changed synchronously.

  In the non-supercharging operation region, as shown in FIG. 5A, the overlap period between the scavenging exhaust valve 33 and the intake valve 6 becomes as small as about 6 degrees in crank angle, and the burned gas to the intake side is reduced. Backflow is suppressed.

  As shown in FIG. 5 (b), the intake valve 6 is opened at a crank angle of about 32 degrees earlier than the non-supercharging operation region and the exhaust valve 7 is operated in the non-supercharging operation. The scavenging exhaust valve 33 is controlled to be closed with a delay of about 26 degrees from the closing timing of the exhaust valve 7 with respect to the closing timing of the exhaust valve 7. As a result, the overlap period between the scavenging exhaust valve 33 and the intake valve 6 is increased, the charging efficiency of fresh air is increased, and the scavenging of burned gas is performed efficiently.

  Further, the ECU 38 fully closes the intake control valve 22 in the partial load operation region at low and medium loads. As a result, an intake vortex with a strong transverse vortex and longitudinal vortex is ejected from the bypass passage 30 into the combustion chamber 5. In the high load operation region, the intake control valve 11 is fully opened. Thus, fresh air is supplied from the intake pipe 17 to the combustion chamber 5.

  As described above, according to the present embodiment, the scavenging exhaust valve 33 is disposed outside the straight line a connecting the centers of the exhaust valves 7 and 7, and the scavenging exhaust valve is used in the supercharging operation region at medium and high loads. 33 is closed after the closing timing of the exhaust valve 7, the scavenging exhaust valve 33 arranged at the position farthest from the intake valve 6 is closed later than the exhaust valve 7, and exhausted by blow-off of fresh air It is possible to efficiently scavenge burnt gas while suppressing the above. As a result, the temperature of the compressed mixture can be lowered, the anti-knocking performance and the filling efficiency can be improved, and the output performance can be improved.

  Furthermore, since it becomes possible to operate with an appropriate ignition timing, the exhaust gas temperature can be lowered accordingly, the heat load on the catalyst can be reduced, and the reliability through quality can be improved.

  Here, when scavenging the burned gas, it is conceivable to provide a scavenging valve outside the pair of intake valves. In such a case, for example, if fuel is injected from one fuel injection valve, the distance between the fuel injection valve and each intake valve increases, so the amount of fuel attached to the wall surface increases and the combustion efficiency increases. There is a concern that will decrease. In order to improve such a fuel adhesion amount, a fuel injection valve is disposed in each intake valve, but the cost increases accordingly, which is not preferable as an industrial product.

  In the present embodiment, since the scavenging exhaust valve 33 is disposed outside each exhaust valve 7, problems such as when a scavenging valve is provided on the intake side can be avoided.

  In the present embodiment, since the intake valve 6 and the scavenging exhaust valve 33 are arranged so as to face each other in a direction orthogonal to the straight line c, the scavenging of burned gas is efficiently performed while suppressing the discharge of fresh air. be able to. That is, in the supercharging operation region in which the intake pressure is higher than the cylinder pressure during the period in which the scavenging exhaust valve 33 and the intake valve 6 overlap, by separating the scavenging exhaust valve 33 and the intake valve 6 as much as possible, Scavenging can be performed efficiently. That is, by arranging the scavenging exhaust valve 33 and the intake valve 6 so as to face each other in the combustion chamber 5, when the piston 4 is in the vicinity of the top dead center, there is no discharge of fresh air. Gas can be scavenged efficiently.

  In the present embodiment, the scavenging exhaust valve 33 is closed earlier than the closing timing during the supercharging operation in the non-supercharging operation region at the time of extremely low load including the AND ring, so that it overlaps with the intake valve 6. Since the period is shortened, the backflow of burned gas can be suppressed and combustion can be prevented from becoming unstable.

  That is, as described above, the operating range in which scavenging is performed is a supercharging operating range in which the intake pressure is higher than the in-cylinder pressure. Under such operating conditions, by providing a sufficient overlap period, The burned gas can be efficiently scavenged. By the way, when the valve timing at which scavenging is performed is used, particularly in an extremely low load region including idling, a large amount of burned gas flows backward from the scavenging exhaust valve 33 to the intake pipe 17 side, and combustion becomes unstable. There is a risk of misfire. In order to prevent such a backflow of burned gas, in the non-supercharging operation region, control is performed to reduce the overlap period by advancing the closing timing of the scavenging exhaust valve 33. In this case, since the scavenging exhaust valve 33 and each exhaust valve 7 are driven to open and close by the single exhaust camshaft 9, the structure of the variable valve timing mechanism 35 can be simplified and the increase in cost can be suppressed.

  In the present embodiment, since the intake valve 6 is opened earlier than the opening timing during the non-supercharging operation in the supercharging operation region, a necessary overlap period can be ensured and sufficient scavenging of burned gas can be achieved. In addition, the charging efficiency of fresh air can be improved, and good flame propagation can be maintained.

  In the above-described embodiment, the opening / closing timing of both the intake valve 6 and the exhaust valve 7 is changed by the variable valve timing mechanism 35. However, as shown in FIGS. The opening / closing timing of the intake valve 6 may be fixed, and only the opening / closing timing of the exhaust valve 7 and the scavenging exhaust valve 33 may be changed.

  That is, in the non-supercharging operation region, the overlap period with the intake valve is reduced by making the exhaust valve and the scavenging exhaust valve earlier than the closing timing during the supercharging operation.

  On the other hand, in the supercharging operation region, a necessary overlap period can be ensured by delaying the closing timing of the exhaust valve and the scavenging exhaust valve. Even in this case, the same effect as the first embodiment can be obtained. Further, it is only necessary to provide the variable valve timing mechanism on the exhaust camshaft side, and the cost can be reduced.

  7 and 8 are views for explaining a spark ignition type internal combustion engine provided with a supercharger according to a second embodiment of the present invention. In the figure, the same reference numerals as those in FIGS. 1 and 4 denote the same or corresponding parts.

  In the internal combustion engine of the second embodiment, a pair of intake valves 6 and 6 are disposed on one side of the combustion chamber 5 with the straight line c interposed therebetween, and a pair of exhaust valves 7 and 7 are disposed on the other side. This is an example in which the scavenging exhaust valves 33 are arranged so as to face the intake valves 6, and the other parts have the same structure as in the first embodiment.

  Also in the second embodiment, the scavenging exhaust valve 33 is disposed at a position farther from the cylinder axis A than the straight line a connecting the centers of the exhaust valves 7 and 7, and the scavenging exhaust valve 33 is exhausted in the supercharging operation region. By closing after the valve 7, the same effect as the first embodiment can be obtained.

It is a schematic block diagram of the spark ignition type internal combustion engine provided with the supercharger by 1st Embodiment of this invention. It is sectional drawing of the said internal combustion engine. It is sectional drawing of the cylinder head of the said internal combustion engine. It is a cross-sectional plan view of the cylinder head. FIG. 3 is a timing diagram for opening and closing the intake and exhaust valves of the internal combustion engine. FIG. 6 is a timing diagram for opening and closing the intake and exhaust valves according to another example of the first embodiment. It is a schematic block diagram of the spark ignition type internal combustion engine by 2nd Embodiment of this invention. It is a cross-sectional top view of the cylinder head of the internal combustion engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Spark ignition internal combustion engine 5 Combustion chamber 6 Intake valve 7 Exhaust valve 33 Scavenging exhaust valve 35 Variable valve timing mechanism a Straight line connecting exhaust valve c Straight line parallel to crankshaft

Claims (5)

A spark ignition internal combustion engine including a supercharger that compresses air and supplies the compressed air to a combustion chamber,
When viewed in the cylinder axis direction, an intake valve is disposed on one side of the combustion chamber across a straight line passing through the cylinder axis and parallel to the crankshaft, and a pair of exhaust valves is disposed on the other side.
A scavenging exhaust valve is disposed at a position away from the cylinder axis from a straight line connecting the centers of the exhaust valves,
The spark ignition internal combustion engine characterized in that the scavenging exhaust valve is closed later than the exhaust valve at least in a supercharging operation region. The spark ignition internal combustion engine according to claim 1,
The spark-ignition internal combustion engine, wherein the intake valve is disposed at a position substantially opposite to the scavenging exhaust valve across a cylinder axis. The spark ignition internal combustion engine according to claim 1,
An exhaust variable valve timing mechanism that varies the opening and closing timing of the scavenging exhaust valve;
The spark variable internal combustion engine, wherein the exhaust variable valve timing mechanism makes the closing timing of the scavenging exhaust valve in the non-supercharging operation region earlier than the closing timing in the supercharging operation region. The spark ignition internal combustion engine according to claim 1,
An intake variable valve timing mechanism that makes the opening / closing timing of the intake valve variable is provided, and the intake variable valve timing mechanism opens the opening timing of the intake valve in the supercharging operation region earlier than the opening timing in the non-supercharging operation region. A spark ignition type internal combustion engine. The spark ignition type internal combustion engine according to any one of claims 1 to 4,
The intake passage in which the supercharger is provided is provided with an intake control valve and a bypass passage that bypasses the intake control valve,
A spark ignition type internal combustion engine, characterized in that a downstream end opening of the bypass passage is arranged to be directed to a gap between the intake valve and the intake opening.

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