JP2006233963A - Four cycle internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a four cycle internal combustion engine improving fuel economy and reducing nitrogen oxide (NOx) without complicating structure of a cylinder head part. <P>SOLUTION: In this invented four cycle internal combustion engine, a gas reservoir chamber 100 communicating to an exhaust port 31 and storing burned gas discharged from a combustion chamber, burned gas flows in the gas reservoir chamber 100 while an exhaust valve composed of a valve part 32a and a stem part 32b is open in expansion stroke, and burned gas stored in the gas reservoir chamber 100 is discharged to the combustion chamber while an exhaust valve is open in intake strokes. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a four-cycle internal combustion engine, and more particularly to a four-cycle internal combustion engine in which swirl is generated by exhaust gas (burned gas) or fresh air (air alone or a mixture of air and fuel).

  Conventionally, an exhaust gas recirculation device (EGR: Exhaust) that slows the combustion of the air-fuel mixture in the combustion chamber, lowers the maximum combustion temperature, and reduces nitrogen oxides (NOx) by returning a part of the exhaust gas to the combustion chamber. A four-cycle internal combustion engine equipped with gas re-circulation is widely used.

For example, a sub-exhaust valve is provided in a sub-exhaust port connected to the combustion chamber, and a gas storage chamber for storing a part of the already burned gas (EGR gas) discharged through the sub-exhaust port is provided. There is known EGR that returns EGR gas stored in a chamber to a combustion chamber at a predetermined timing (see, for example, Patent Document 1).
Japanese Patent Laid-Open No. 5-86992 (pages 4-5 and 4-5)

  In the four-cycle internal combustion engine provided with the above-described conventional exhaust gas recirculation device (EGR), the fuel consumption can be improved along with the reduction of the pumping loss. However, in recent years, further improvement of the fuel consumption has been desired.

  In addition, the above-described four-cycle internal combustion engine equipped with the conventional EGR requires a sub exhaust port and a sub exhaust valve in addition to a main exhaust port and a main exhaust valve that discharge exhaust gas from the combustion chamber.

  For this reason, there has been a problem that the structure of the cylinder head portion becomes complicated, leading to an increase in manufacturing cost.

  Therefore, the present invention has been made in view of such circumstances, and can further improve fuel efficiency and reduce nitrogen oxides (NOx) without complicating the structure of the cylinder head portion 4. An object is to provide a cycle internal combustion engine.

  In order to solve the above-described problems, the first to third inventions of the present application have the following features. First, the first feature of the first invention is that a combustion chamber 40, an intake passage (intake port) 21 that opens to the combustion chamber, an exhaust passage (exhaust port) 31 that opens to the combustion chamber, and the intake passage A four-cycle internal combustion engine (engine) 10 having an intake valve 22 for opening and closing the combustion chamber side opening of the engine and an exhaust valve 32 for opening and closing the combustion chamber side opening of the exhaust passage, A gas storage chamber 100 for storing the burnt gas G discharged from the combustion chamber, and the burnt gas flows into the gas storage chamber while the exhaust valve is open in an expansion stroke or an exhaust stroke; The gist is that the burned gas stored in the gas storage chamber is discharged into the combustion chamber while the exhaust valve is open in the intake stroke.

  According to such a feature, the amount of internal EGR can be made larger than before, so that the pumping loss is reduced.

  Further, according to this feature, since the gas storage chamber that stores the burned gas discharged from the combustion chamber is provided that communicates with the exhaust passage, a dedicated intake / exhaust passage and a valve that communicate with the gas storage chamber are provided. There is no need.

  That is, according to this feature, it is possible to provide a four-cycle internal combustion engine that can further improve fuel economy and reduce nitrogen oxides (NOx) without complicating the structure of the cylinder head portion.

  A second feature of the first invention of the present application relates to the first feature, wherein when the exhaust valve is opened in the expansion stroke, the burned gas flows into the gas storage chamber, and the intake stroke in the intake stroke The gist is that the burned gas is discharged into the combustion chamber while the exhaust valve is open.

  A third feature of the first invention of the present application relates to the first feature, wherein the timing at which the burned gas is discharged into the combustion chamber is within an overlap period in which the intake valve and the exhaust valve are open. It is a summary.

  A fourth feature of the first invention of the present application relates to the first feature, wherein the exhaust valve has a valve portion 32a for opening and closing an opening portion of the exhaust passage to the combustion chamber, and a handle portion extending from the valve portion. And a gas communication path (burned gas guide pipe) 110 communicating with the gas storage chamber from the periphery of the valve portion in the exhaust path.

  A fifth feature of the first invention of the present application relates to the fourth feature, wherein the valve portion side end portion 110e of the gas communication path is oriented in a direction along the peripheral portion 40p of the combustion chamber. Is the gist.

  A sixth feature of the first invention of the present application is related to the first feature, comprising a fresh air storage chamber 69 that communicates with the intake passage and stores fresh air flowing through the intake passage. The gist is that fresh air stored in the fresh air storage chamber is sucked into the combustion chamber while the valve is open.

  The seventh feature of the first invention of the present application relates to the first feature, and is a fresh air storage chamber 69 for storing fresh air flowing in the intake passage, and the fresh air storage chamber and the combustion chamber side of the intake passage. A first fresh air communication passage 70 communicating with a portion in the vicinity of the opening, and fresh air flows into the fresh air storage chamber through the first fresh air communication passage due to pressure fluctuations in the intake passage, The gist is that the fresh air stored in the fresh air storage chamber is sucked into the combustion chamber through the first fresh air communication passage while the intake valve is open.

  An eighth feature of the first invention of the present application relates to the seventh feature, and includes a second fresh air communication passage that communicates the fresh air storage chamber and the intake passage, and fresh air is generated by pressure fluctuations in the intake passage. The fresh air stored in the fresh air storage chamber flows into the fresh air storage chamber via the first and second fresh air communication passages while the intake valve is open during the intake stroke. The gist is to be sucked into the combustion chamber through one fresh air communication passage.

  A ninth feature of the first invention of the present application is related to the eighth feature, wherein the second fresh air communication passage communicates with a portion near the downstream side of the throttle valve of the intake passage.

  A tenth feature of the first invention of the present application relates to the sixth feature, wherein the gas communication passage that communicates the gas storage chamber and the portion near the combustion chamber side opening of the exhaust passage is tangent to the periphery of the combustion chamber. The gist is that they are arranged in the direction.

  An eleventh feature of the first invention of the present application is related to the tenth feature, wherein the first fresh air communication passage that communicates the fresh air storage chamber and the vicinity of the opening on the combustion chamber side of the intake passage is the center of the combustion chamber. The gist is that they are arranged so as to be tangent to a concentric circle formed on the side.

  A first feature of the second invention of the present application is a combustion chamber, an intake passage that opens to the combustion chamber, an exhaust passage that opens to the combustion chamber, an intake valve that opens and closes the combustion chamber side opening of the intake passage, A four-cycle internal combustion engine having an exhaust valve that opens and closes the combustion chamber side opening of the exhaust passage, and communicates with the intake passage via a first fresh air communication passage 70 to flow fresh air flowing through the intake passage. And the fresh air stored in the fresh air storage chamber 69 is sucked into the combustion chamber while the intake valve is open during the intake stroke. .

  A second feature of the second invention of the present application is the first feature of the second invention, comprising a second fresh air communication passage 71 for communicating the fresh air storage chamber 69 and the intake passage, wherein the intake valve While the air is closed, fresh air flows into the fresh air storage chamber 69 via the first and second fresh air communication passages 70 and 71, and the intake valve is opened during the intake stroke. The gist is that fresh air stored in the fresh air storage chamber 69 is sucked into the combustion chamber via the first fresh air communication passage 70.

  A third feature of the second invention of the present application is the second feature of the second invention, wherein the second fresh air communication passage communicates with a portion near the downstream side of the throttle valve 65 of the intake passage. This is the gist.

  A first feature of the third invention of the present application is a combustion chamber, an intake passage that opens to the combustion chamber, an exhaust passage that opens to the combustion chamber, and an intake valve that opens and closes the combustion chamber side opening of the intake passage. A four-cycle internal combustion engine comprising an exhaust valve that opens and closes the combustion chamber side opening of the exhaust passage and a throttle valve that changes a passage area of the intake passage, the intake passage being downstream of the throttle valve A third fresh air communication passage that communicates the vicinity portion with the combustion chamber side opening vicinity portion is provided, and the downstream end portion of the third fresh air communication passage is disposed so as to be tangential to the inner periphery of the combustion chamber. The gist of this is.

  According to the features of the present invention, it is possible to provide a four-cycle internal combustion engine that can further improve fuel efficiency and reduce nitrogen oxides (NOx) without complicating the structure of the cylinder head portion.

  Next, a first embodiment of a four-cycle internal combustion engine according to the present invention will be described with reference to the drawings. In the following description of the drawings, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic and ratios of dimensions and the like are different from actual ones.

  Accordingly, specific dimensions and the like should be determined in consideration of the following description. Moreover, it is a matter of course that portions having different dimensional relationships and ratios are included between the drawings.

(Schematic configuration of a 4-cycle internal combustion engine)
FIG. 1 shows a schematic configuration of an engine 10 that is a four-cycle internal combustion engine according to the present embodiment. Specifically, FIG. 1 is a side view of the engine 10 showing a section of the cylinder head 10sh as a cross section.

  As shown in the figure, the engine 10 includes an intake port 21 that constitutes the cylinder head inner portion of the intake passage and opens to the combustion chamber 40, and an exhaust gas that constitutes the cylinder head inner portion of the exhaust passage and opens to the combustion chamber. Port 31.

  The intake port 21 is provided with an intake valve 22, and the exhaust port 31 is provided with an exhaust valve 32.

  The intake valve 22 is reciprocated at a predetermined timing by an intake side camshaft 23 disposed on the upper part of the cylinder head 10sh. When the intake valve 22 is reciprocated by the intake camshaft 23, the intake port 21 opens and closes the combustion chamber side opening (the valve seat 24 portion shown in FIG. 2).

  Similarly, the exhaust valve 32 is reciprocated at a predetermined timing by an exhaust side camshaft 33 disposed at the upper part of the cylinder head 10sh. When the exhaust valve 32 is reciprocated by the exhaust camshaft 33, the exhaust valve 31 opens and closes the combustion chamber side opening (the valve seat 34 portion shown in FIG. 2) of the exhaust port 31.

  A cylinder 51 is formed below the cylinder head 10 sh, and a piston 52 that rotates a crankshaft (not shown) via a connecting rod 53 is disposed in the cylinder 51.

(Configuration of cylinder head)
Next, a specific configuration of the cylinder head 10sh will be described with reference to FIGS.

  FIG. 2 is a cross-sectional view of the cylinder head 10 sh portion, specifically, a cross-sectional view of the cylinder head 10 sh portion along a direction orthogonal to the intake side cam shaft 23 and the exhaust side cam shaft 33. FIG. 3 is an arrow view from the F3 direction shown in FIG.

  As shown in FIGS. 2 and 3, the intake valve 22 includes an opening to the combustion chamber 40 (see FIG. 1) of the intake port 21, specifically, a valve portion 22 a that opens and closes a portion of the valve seat 24; The handle portion 22b extends from the valve portion 22a.

  Similarly, the exhaust valve 32 includes an opening portion of the exhaust port 31 to the combustion chamber 40 (see FIG. 1), specifically, a valve portion 32a for opening and closing a portion of the valve seat 34, and a handle portion extending from the valve portion 32a. 32b.

  Further, the exhaust port 31 is provided with a burnt gas induction pipe (gas communication passage) 110 that communicates with the gas storage chamber 100 from the periphery of the valve portion 32a. Specifically, the end portion 110e of the burnt gas guiding pipe 110 closes the valve portion 32a while ensuring a distance that does not interfere with the valve portion 32a when the opening of the exhaust port 31 is closed. It is provided on the exhaust side from the portion 32a.

  Further, a gas storage chamber 100 that communicates with the exhaust port 31 and stores the already burned gas G (see FIG. 5) discharged from the combustion chamber 40 is provided on the side of the cylinder head 10 sh.

  The burned gas G flows into the gas storage chamber 100 while the exhaust valve 32 is open during the expansion stroke or exhaust stroke of the engine 10. Further, the already burned gas G (EGR gas) stored in the gas storage chamber 100 is discharged into the combustion chamber 40 while the exhaust valve 32 is open in the intake stroke of the engine 10.

  A more specific timing of inflow of the burnt gas G (EGR gas) into the gas storage chamber 100 and a discharge timing of the burnt gas G (EGR gas) from the gas storage chamber 100 will be described later.

  FIG. 4 is an enlarged view of the vicinity of the exhaust port 31 including the end portion 110e of the burnt gas guide pipe 110 shown in FIG.

  As shown in the figure, the end portion 110e of the burnt gas guiding pipe 110 has a slightly curved shape. Specifically, the end portion 110e is directed in a direction along the peripheral portion 40p (see FIG. 6) of the combustion chamber 40.

(Inflow / exhaust operation of burnt gas)
Next, referring to FIG. 5 to FIG. 7, the inflow of the burned gas G into the gas storage chamber 100 provided in the engine 10 and the gas storage chamber 100 of the burned gas G (EGR gas) are described. The operation relating to the discharge of the gas will be described.

  FIG. 5 is a partially enlarged cross-sectional view of the engine 10. The burnt gas G stored in the gas storage chamber 100 is discharged into the combustion chamber 40 while the exhaust valve 32 is open in the intake stroke of the engine 10.

  FIG. 6 is an enlarged view of the combustion chamber 40 including the gas storage chamber 100 and the already burned gas guide pipe 110. Specifically, FIG. 6 is a diagram showing the combustion chamber 40 including the gas storage chamber 100 and the already burned gas guide pipe 110 from the F6 direction shown in FIG.

  As shown in the figure, the end portion 110e of the already burned gas guide pipe 110 provided in the exhaust port 31 has a slightly curved shape. Specifically, the end portion 110 e faces the direction along the peripheral portion 40 p of the combustion chamber 40.

  In the present embodiment, the end portion 110e is directed in a direction along the upper surface of the piston 52, that is, in a substantially horizontal direction.

  Since the end portion 110e faces the direction along the peripheral portion 40p of the combustion chamber 40, the already burned gas G (EGR gas) stored in the gas storage chamber 100 can be discharged into the swirl portion 40p. it can.

  For this reason, the flame extinguishing region mainly generated in the peripheral portion 40p (the region where the flame disappears by cooling when the flame propagates), the so-called quench area QA, unburned gas is reduced, and the amount of hydrocarbon gas (HC) discharged is reduced. Can be suppressed.

  More specifically, when the burnt gas G (EGR gas) is discharged into the peripheral portion 40p in a swirl shape, the unburned gas in the quench area QA is evaporated by the hot burned gas G (EGR gas). When the unburned gas evaporates, the quench area QA is filled with the burned gas G (EGR gas), and the inflow of unburned gas into the quench area QA is prevented.

  For this reason, the unburned gas in the quench area QA is reduced, and the discharge amount of hydrocarbon gas (HC) can be suppressed.

  In the present embodiment, the inner diameter of the burnt gas guide pipe 110 is set to 2.2 to 2.5 mm. In addition, it is preferable to change the internal diameter of the already burned gas guide pipe 110, the pipe length, and the capacity of the gas storage chamber 100 according to the displacement of the engine 10 or the like.

  FIG. 7 shows the timing of the inflow of the burnt gas G into the gas storage chamber 100 and the discharge of the burnt gas G (EGR gas) from the gas storage chamber 100. In FIG. 7, a dotted line “EX” indicates the opening degree of the exhaust valve 32 according to the crankshaft angle. A dotted line “IN” indicates the opening degree of the intake valve 22 according to the crankshaft angle.

  The solid line “inflow” indicates the capacity of the already burned gas G flowing into the gas storage chamber 100 and the inflow timing. A solid line “exhaust” indicates the capacity of the burned gas G (EGR gas) discharged from the gas storage chamber 100 and the discharge timing.

  As shown in FIG. 7, the burned gas G is a timing at which the exhaust valve 32 is opened while the piston 52 is pushed down in the direction of the crankshaft (not shown) by the expansion stroke of the engine 10, that is, the expansion of the combustion gas. Then, it flows into the gas storage chamber 100.

  In addition, the burnt gas G stored in the gas storage chamber 100 is in the intake stroke of the engine 10, that is, at the timing when the exhaust valve 32 is opened while the air-fuel mixture flows from the intake port 21 into the combustion chamber 40. It is discharged into the combustion chamber 40.

  More specifically, as shown in FIG. 7, the timing at which the burnt gas G (EGR gas) is discharged to the combustion chamber 40 is set in the vicinity of the timing at which the exhaust valve 32 is closed.

(Action / Effect)
Next, the operation and effect of the engine 10 including the gas storage chamber 100 and the already burned gas guide pipe 110 described above will be described with reference to the data shown in FIGS. Note that the data shown in FIGS. 8 to 11 are measured under the following conditions.

・ Engine displacement: Approximately 125cc
・ Engine speed during measurement: 3,000 rpm (0.6 kW output)
FIG. 8 is a graph showing the relationship between the capacity of the gas storage chamber 100 and nitrogen oxides (NOx). As shown in the figure, when the capacity of the gas storage chamber 100 is extremely small (P11 in the figure, about 0 cc) and when the capacity of the gas storage chamber 100 is about 65 cc (P12 in the figure), NOx. Is reduced by about 15%.

  As described above, since the engine 10 is provided with the gas storage chamber 100 that communicates with the exhaust port 31 and stores the already burned gas G discharged from the combustion chamber 40, a dedicated suction communication with the gas storage chamber 100 is provided. There is no need to provide an exhaust port and a valve.

  That is, according to the engine 10 including the gas storage chamber 100 and the burnt gas guide pipe 110, a four-cycle internal combustion engine that can reduce nitrogen oxide (NOx) without complicating the structure of the cylinder head 10sh portion. Can be provided.

  FIG. 9 is a graph showing the relationship between the capacity of the gas storage chamber 100 and the fuel consumption rate. As shown in the figure, when the capacity of the gas storage chamber 100 is extremely small (P21 in the figure, about 0 cc) and when the capacity of the gas storage chamber 100 is about 45 cc (P22 in the figure), the fuel consumption The rate has improved by about 10%. FIG. 10 is a graph showing the relationship between the capacity of the gas storage chamber 100 and the opening of the throttle (throttle valve).

  In the engine 10 including the gas storage chamber 100 and the burnt gas guide pipe 110, the burnt gas G (EGR gas) is discharged (refluxed) into the combustion chamber 40 in the intake stroke, thereby increasing the internal EGR amount. Since the pumping loss of the engine 10 is reduced, the throttle valve of the engine 10 can be set to the open side, and the fuel efficiency can be improved.

  Furthermore, in the engine 10 including the gas storage chamber 100 and the already burned gas guide pipe 110, since the swirl can be generated in the combustion chamber 40, the combustion efficiency can be further improved.

  FIG. 11 is a graph showing the relationship between the capacity of the gas storage chamber 100 and hydrocarbon gas (HC). As shown in the figure, when the capacity of the gas storage chamber 100 is extremely small (P31 in the figure, about 0 cc) and when the capacity of the gas storage chamber 100 is about 30 cc (P32 in the figure), HC Is reduced by about 7%.

  Although a large amount of HC is generated in the quench area QA, the end 110e of the already burned gas guide pipe 110 is directed in the direction along the peripheral portion 40p of the combustion chamber 40. The combustion gas G (EGR gas) can be discharged to the peripheral portion 40p in a swirl shape. That is, in the engine 10, the unburned gas in the quench area QA is reduced by the EGR gas, so that the amount of HC generated can be suppressed. Further, in the engine 10, the EGR gas is discharged (refluxed) into the combustion chamber 40 in a swirl manner, so that the EGR gas located near the peripheral portion 40p and the new air-fuel mixture flowing from the intake port 21 are stratified. Figured.

  That is, it is possible to improve the EGR rate (a numerical value obtained by expressing the amount of EGR gas recirculated to the combustion chamber 40 by the intake air amount), and further improve the fuel consumption rate and purify the exhaust gas.

  Further, as described above, the inner diameter, the tube length, and the capacity of the gas storage chamber 100 of the burned gas guide tube 110 can be adjusted according to the displacement of the engine 10 and the like. For this reason, according to the characteristics of the engine 10 and the like, the timing of discharging the already burned gas G (EGR gas) to the combustion chamber 40 can be easily set to an appropriate rotational speed region.

(Other embodiments)
As described above, the contents of the present invention have been disclosed through the first embodiment of the present invention. However, it should not be understood that the description and drawings constituting a part of this disclosure limit the present invention. From this disclosure, various alternative embodiments will be apparent to those skilled in the art.

  For example, in the first embodiment of the present invention described above, the burnt gas G flows into the gas storage chamber 100 at the timing when the exhaust valve 32 is opened during the expansion stroke of the engine 10, and the exhaust valve is discharged during the intake stroke of the engine 10. Although the burned gas G (EGR gas) is discharged into the combustion chamber 40 at the timing when the gas is opened 32, the inflow and discharge timing of the burned gas G is not necessarily limited to the timing. Absent.

  Further, in the above-described first embodiment of the present invention, the end 110e of the burnt gas guide pipe 110 is positioned around the valve portion 32a. However, the burnt gas guide pipe 110 is not necessarily provided. I do not care. In this case, for example, the burnt gas guide pipe 110 may be terminated at the position PV shown in FIG. 4, that is, at the inner wall surface of the exhaust port 31.

  As described above, the present invention naturally includes various embodiments that are not described herein. Therefore, the technical scope of the present invention is defined only by the invention specifying matters according to the scope of claims reasonable from the above description.

  12 and 13 are diagrams for explaining a second embodiment of the present invention. The second embodiment is an example in which a fresh air storage chamber 69 is provided in addition to the gas storage chamber 67 similar to the first embodiment. In the present embodiment, fresh air includes both the case of air alone and the case of a mixture of air and fuel.

  The engine in the second embodiment is a four-cycle single-cylinder four-valve engine provided with two intake valves and two exhaust valves for each cylinder. The engine has a schematic structure in which a cylinder block, a cylinder head, and a head cover are stacked and fastened on an upper wall of a crankcase.

  A combustion recess 61 b that constitutes the top wall of the combustion chamber is in contact with the cylinder block side mating surface 61 a of the cylinder head 61. In the combustion recess 61b, two intake valve openings 62a and 62b and two exhaust valve openings 63a and 63b are formed. These intake valve opening and exhaust valve opening are opened and closed by an intake valve and an exhaust valve, respectively. Reference numeral 73 denotes a spark plug disposed substantially at the center of the combustion recess 61b.

  The intake valve openings 62a and 62b are connected to branch intake ports 62c and 62d that constitute a portion of the intake passage in the cylinder head. The two branched intake ports 62c and 62d are branched from one common main intake port 62e that also constitutes the cylinder head inner portion of the intake passage. An intake pipe 64 constituting the cylinder head outer portion of the intake passage is connected to the external connection port of the main intake port 62e. The intake pipe 64 is provided with a throttle valve 65 for controlling the intake passage area.

  Branch exhaust ports 63c and 63d constituting the cylinder head inner portion of the exhaust passage are connected to the exhaust valve openings 63a and 63b. The two branch exhaust ports 63c and 63d are joined to one common main exhaust port 63e that also constitutes an inner portion of the exhaust passage in the cylinder head. An exhaust pipe 66 constituting the cylinder head outer portion of the exhaust passage is connected to the external connection port of the main exhaust port 63e.

  A sealed box-like gas storage chamber 67 similar to the gas storage chamber 100 in the first embodiment is disposed outside the exhaust side of the cylinder head 61. One end 68a of a burnt gas induction passage (gas communication passage) 68 is connected to the gas storage chamber 67 so as to communicate with the gas storage chamber. The other end 68b of the gas communication passage 68 is connected so as to communicate with the downstream vicinity of the exhaust valve opening 63b of the one branch exhaust port 63d.

  Here, the other end 68b of the gas communication path 68 is formed so as to face the combustion chamber through the exhaust valve opening 63b and to face in a tangential direction with respect to the inner periphery of the combustion chamber. That is, the axial direction and arrangement position of the gas guide passage 68 are such that the exhaust gas stored in the gas storage chamber 67 is sucked into the combustion chamber while forming a swirl flow (lateral vortex) along the inner periphery of the combustion chamber. Is set to

  A piston 67a is disposed in the gas storage chamber 67 so as to be able to advance and retract. The piston 67a is driven back and forth by an actuator 67b. Thereby, the volume of the gas storage chamber 67 can be freely changed.

  A fresh air storage chamber 69 having a sealed box shape similar to that of the gas storage chamber 67 is disposed outside the cylinder head 61 on the intake side. One end 70 a of the first fresh air communication passage 70 is connected to the fresh air storage chamber 69 so as to communicate with the fresh air storage chamber 69. The other end 70b of the first fresh air communication passage 70 is connected so as to communicate with the upstream vicinity of the intake valve opening 62a of the one branch intake port 62c.

  The other end 70b of the first fresh air communication passage 70 faces the combustion chamber via the intake valve opening 62a and faces the tangential direction with respect to the concentric circle H formed near the center of the combustion chamber. Is formed. That is, the axial direction and the arrangement position of the first fresh air communication passage 70 are such that fresh air stored in the fresh air storage chamber 69 is sucked into the combustion chamber as a swirl flow (lateral vortex) near the center of the combustion chamber. Is set to be.

  Here, the swirl flow due to the exhaust gas discharged from the gas storage chamber 67 is formed near the outer periphery of the combustion chamber, and the swirl flow due to the fresh air discharged from the fresh air storage chamber 69 is formed closer to the spark plug 71 side. The two swirl flows are stratified, and so-called stratified combustion is realized.

  In addition, one end 71a of the second fresh air communication passage 71 is connected to the fresh air storage chamber 69 so as to communicate with the room. The other end 71 b of the second fresh air communication passage 71 communicates with a portion closest to the downstream side of the throttle valve 65 located at the idling opening degree of the intake pipe 64.

  Furthermore, a piston 69a is disposed in the fresh air storage chamber 69 so as to freely advance and retract, and the piston 69a is driven forward and backward by an actuator 69b, whereby the volume of the fresh air storage chamber 69 can be freely changed. It has become.

  The actuators 67b and 69b are supplied with a gas storage chamber volume control signal A and a fresh air storage chamber volume control signal B from the ECU 74. This ECU receives signals indicating the engine operating state such as the engine rotational speed a, the throttle opening b, the engine temperature c, and the like, and based on these input signals, the optimal gas storage chamber volume and fresh air storage chamber volume are determined. The control signals A and B for realizing these volumes are output to the actuators 67b and 69b.

  In the second embodiment, the gas storage chamber 67 communicates with the vicinity of the downstream side of the exhaust valve opening 63b of the branch exhaust port 63d through the gas communication path 68, so that the exhaust valve opens near the end of the expansion stroke. When 63 b is opened, a high blowdown pressure of the exhaust gas acts on the gas communication path 68, and the exhaust gas flows into the gas storage chamber 67 and is stored in the gas storage chamber 67 with a positive pressure. Then, when the piston starts to descend before the exhaust valve closes the exhaust valve opening 63b in the intake stroke, and the combustion chamber becomes negative pressure, it is stored in the gas storage chamber 67 as indicated by symbol D in FIG. Exhaust gas is discharged into the combustion chamber through the exhaust valve opening 63b.

  The gas communication path 68 is arranged so that its axis is substantially tangent to the inner periphery of the combustion chamber through the exhaust valve opening 63b, so that the exhaust gas from the gas storage chamber 67 is combusted. The exhaust gas is discharged in the tangential direction near the periphery of the chamber, so that a swirl flow of exhaust gas is formed near the periphery of the combustion chamber.

  The fresh air storage chamber 69 has a negative pressure during the previous intake stroke, and communicates with the intake valve opening vicinity of the intake passage and the throttle valve downstream side by the first and second fresh air communication passages 70 and 71. Therefore, when the intake valve closes the intake valve opening due to the end of the intake stroke, fresh air is stored in the fresh air storage chamber 69.

  When the piston descends and the intake valve opens the intake valve opening 62a in the next intake stroke, the fresh air stored in the fresh air storage chamber 69 passes through the first fresh air communication passage 70 and opens the intake valve. It is sucked into the combustion chamber from 62a. In this case, since the fresh air storage chamber 69 communicates with the portion immediately downstream of the throttle valve downstream of the intake passage by the second communication passage 71, fresh air is supplied to the second communication passage 71, the fresh air storage chamber 69, and the first air passage. The fresh air is continuously inhaled to the vicinity of the end of the intake stroke through the fresh air communication passage 70, and more fresh air is sucked into the combustion chamber toward the end of the intake stroke (see symbol E in FIG. 13).

  The first fresh air communication passage 70 is arranged so that the axis thereof is substantially tangent to the concentric circle H formed near the ignition plug 73 of the combustion chamber through the intake valve opening 62a. Fresh air from the fresh air storage chamber 69 is sucked in a tangential direction near the center of the combustion chamber, so that a fresh swirl flow is formed near the center of the combustion chamber.

  In this way, a swirl flow due to exhaust gas is formed near the outer periphery of the combustion chamber, and a swirl flow due to fresh air is formed near the spark plug 73 side. This outer and inner double swirl flow realizes stratification, which can reduce the pumping loss by introducing exhaust gas and improve fuel efficiency. At the same time, the combustibility by fresh air swirl flow and the exhaust gas property Improvements can be made.

  In the first embodiment, (1) an example in which only the gas storage chamber 100 is provided will be described. In the second embodiment, (2) both the gas storage chamber 67 and the fresh air storage chamber 69 are provided. Although the case where the fresh air storage chamber 69 is communicated with the downstream side of the throttle valve has been described, in the present invention, still another embodiment can be adopted as follows.

  (3) While only the fresh air storage chamber 69 is provided, the fresh air storage chamber 69 and the intake passage are communicated by the first and second fresh air communication passages 70 and 71.

  (4) Only the fresh air storage chamber 69 is provided, the fresh air storage chamber 69 and the intake passage are communicated with each other by the first fresh air communication passage 70, and the second fresh air communication passage 71 is not provided.

  (5) Both the gas storage chamber 67 and the fresh air storage chamber 69 are provided. However, in this case, the fresh air storage chamber 69 and the intake passage communicate with each other only through the first fresh air communication passage 70.

  (6) As shown in FIG. 15, the gas storage chamber 67 is provided on the exhaust side, while the fresh air storage chamber 69 is not provided on the intake side, and the portion near the throttle valve downstream of the intake passage and the portion near the intake valve opening Are communicated directly through the third fresh air communication passage 72. The upstream end portion 72a of the third fresh air communication passage 72 is connected to the vicinity of the throttle valve downstream, the downstream end portion 72b is connected to the vicinity of the intake valve opening, and the downstream end portion 72b is further to the center side of the combustion chamber. The axial direction and the arrangement position are set so as to form a ki suwar flow. More specifically, the downstream end portion 72b is disposed so as to face the tangential direction with respect to the inner periphery of the combustion chamber.

  FIG. 14 shows experimental results for explaining the fuel efficiency improvement effect in the cases (1) to (6). In this experiment, the gas storage chamber, fresh air storage of the fuel consumption rate when traveling at a speed of 30, 50, 70 km / h on a motorcycle with an engine displacement of 125 cc, a gas storage chamber volume of 30 cc, and a fresh air storage chamber volume of 30 cc. The improvement effect with respect to the comparative example vehicle which is not equipped with any of the rooms was investigated. In the case of (6) above, experimental results are shown only when traveling at 30 km / h.

  From FIG. 13, it can be seen that in any of the cases (1) to (6), the fuel consumption rate is improved as compared with the comparative example. In particular, in the cases of (4), (3), and (2), at 30 km / h, the fuel consumption rate is greatly improved to 13%, 16%, and 21% as compared with the comparative example.

1 is a schematic configuration diagram of a four-cycle internal combustion engine according to a first embodiment of the present invention. It is sectional drawing of the cylinder head part of the 4-cycle internal combustion engine which concerns on the said embodiment. FIG. 3 is an arrow view from the F3 direction shown in FIG. 2. FIG. 4 is an enlarged view around an exhaust port including an end portion of a burnt gas induction pipe shown in FIG. 3. It is a partial expanded sectional view of the 4-cycle internal combustion engine which concerns on the said embodiment. It is an enlarged view of the combustion chamber containing the gas storage chamber and the already burned gas induction pipe which concern on the said embodiment. It is a figure which shows the timing of inflow of the already burned gas to the gas storage chamber which concerns on the said embodiment, and discharge | emission from the gas storage chamber of existing combustion gas (EGR gas). It is a graph which shows the relationship between the capacity | capacitance of the gas storage chamber which concerns on the said embodiment, and nitrogen oxide (NOx). It is a graph which shows the relationship between the capacity | capacitance of the gas storage chamber which concerns on the said embodiment, and a fuel consumption rate. It is a graph which shows the relationship between the capacity | capacitance of the gas storage chamber which concerns on the said embodiment, and the opening degree of a throttle (throttle valve). It is a graph which shows the relationship between the capacity | capacitance of the gas storage chamber which concerns on the said embodiment, and hydrocarbon gas (HC). It is a schematic block diagram of the 4-cycle internal combustion engine which concerns on 2nd Embodiment of this invention. It is a figure for demonstrating the introduction timing of the exhaust gas in the said 2nd Embodiment, and fresh air. It is a figure for demonstrating the fuel-consumption-rate improvement effect in various embodiment which concerns on this invention. It is a figure which shows the modification of the said 2nd Embodiment.

Explanation of symbols

10 Engine 10sh Cylinder head 21 Intake port (intake passage)
22 intake valve 22a valve portion 22b handle portion 23 intake side camshaft 24 valve seat (combustion chamber side opening of intake passage)
31 Exhaust port (exhaust passage)
32 Exhaust valve 32a Valve portion 32b Handle portion 33 Exhaust side camshaft 34 Valve seat (combustion chamber side opening of exhaust passage)
40 Combustion chamber 40p Circumferential part 51 Cylinder 52 Piston 65 Throttle valve 68, 110 Pre-combustion gas guide pipe (gas communication path)
69 Fresh air storage chamber 70 First fresh air communication passage 71 Second fresh air communication passage 72 Third fresh air communication passage 100 Gas storage chamber 110e End G Burned gas H Concentric circle QA Quench area

Claims (15)

A combustion chamber; an intake passage that opens to the combustion chamber; an exhaust passage that opens to the combustion chamber; an intake valve that opens and closes a combustion chamber side opening of the intake passage; and a combustion chamber side opening of the exhaust passage that opens and closes A four-cycle internal combustion engine with an exhaust valve,
A gas storage chamber that communicates with the exhaust passage and stores the already burned gas discharged from the combustion chamber;
While the exhaust valve is open in the expansion stroke or the exhaust stroke, the burned gas flows into the gas storage chamber,
A four-cycle internal combustion engine, wherein the burned gas stored in the gas storage chamber is discharged into the combustion chamber while the exhaust valve is open in an intake stroke. In Claim 1, when the exhaust valve is opened in the expansion stroke, the burned gas flows into the gas storage chamber,
A four-cycle internal combustion engine, wherein the burned gas is discharged into the combustion chamber while the exhaust valve is open in the intake stroke. 2. The four-cycle internal combustion engine according to claim 1, wherein the timing at which the burned gas is discharged into the combustion chamber is within an overlap period in which the intake valve and the exhaust valve are open. In Claim 1, the said exhaust valve has a valve part which opens and closes the above-mentioned combustion chamber side opening of the above-mentioned exhaust passage, and a handle part extended from this valve part,
A four-cycle internal combustion engine, further comprising a gas communication path communicating from the periphery of the valve portion in the exhaust path to the gas storage chamber. 5. The four-cycle internal combustion engine according to claim 4, wherein an end portion of the gas communication passage on the valve portion side is directed in a direction along a peripheral portion of the combustion chamber. In Claim 1, provided with a fresh air storage chamber that communicates with the intake passage and stores fresh air flowing through the intake passage,
A four-stroke internal combustion engine, wherein fresh air stored in the fresh air storage chamber is sucked into the combustion chamber while the intake valve is open in an intake stroke. The fresh air storage chamber according to claim 1, wherein the fresh air storage chamber communicates with the intake passage and stores fresh air flowing through the intake passage.
A first fresh air communication passage that communicates the fresh air storage chamber and a portion near the combustion chamber side opening of the intake passage;
Due to pressure fluctuations in the intake passage, fresh air flows into the fresh air storage chamber via the first fresh air communication passage,
A four-cycle internal combustion engine in which fresh air stored in the fresh air storage chamber is sucked into the combustion chamber through the first fresh air communication passage while the intake valve is open in the intake stroke. organ. In Claim 7, provided with the 2nd fresh air communication passage which connects the above-mentioned fresh air storage room and the above-mentioned intake passage,
Due to pressure fluctuations in the intake passage, fresh air flows into the fresh air storage chamber via the first and second fresh air communication passages,
4 cycles, wherein fresh air stored in the fresh air storage chamber is sucked into the combustion chamber through the first fresh air communication passage while the intake valve is open in the intake stroke. Internal combustion engine. 9. The four-cycle internal combustion engine according to claim 8, wherein the second fresh air communication passage communicates with a portion near the downstream side of the throttle valve of the intake passage. 7. The four-cycle internal combustion engine according to claim 6, wherein the gas communication passage communicating the gas storage chamber and the exhaust passage is disposed so as to be directed in a tangential direction with respect to the inner periphery of the combustion chamber. 11. The first fresh air communication passage communicating the fresh air storage chamber and a portion near the combustion chamber side opening of the intake passage is directed tangentially to a concentric circle formed on the center side of the combustion chamber. A four-cycle internal combustion engine, characterized in that A combustion chamber; an intake passage that opens to the combustion chamber; an exhaust passage that opens to the combustion chamber; an intake valve that opens and closes a combustion chamber side opening of the intake passage; and a combustion chamber side opening of the exhaust passage that opens and closes A four-cycle internal combustion engine with an exhaust valve,
A fresh air storage chamber that communicates with the intake passage via a first fresh air communication passage and stores fresh air flowing through the intake passage;
A four-stroke internal combustion engine, wherein fresh air stored in the fresh air storage chamber is sucked into the combustion chamber while the intake valve is open in an intake stroke. In Claim 12, provided with a second fresh air communication passage that communicates the fresh air storage chamber and the intake passage,
While the intake valve is closed, fresh air flows into the fresh air storage chamber via the first and second fresh air communication passages,
4 cycles, wherein fresh air stored in the fresh air storage chamber is sucked into the combustion chamber through the first fresh air communication passage while the intake valve is open in the intake stroke. Internal combustion engine. 14. The four-cycle internal combustion engine according to claim 13, wherein the second fresh air communication passage communicates with a portion near the downstream side of the throttle valve of the intake passage. A combustion chamber; an intake passage that opens to the combustion chamber; an exhaust passage that opens to the combustion chamber; an intake valve that opens and closes a combustion chamber side opening of the intake passage; and a combustion chamber side opening of the exhaust passage that opens and closes A four-cycle internal combustion engine comprising an exhaust valve and a throttle valve that changes a passage area of the intake passage,
A third fresh air communication passage communicating the downstream portion of the intake passage with respect to the throttle valve and the vicinity of the opening on the combustion chamber side; a downstream end of the third fresh air communication passage is an inner periphery of the combustion chamber A four-cycle internal combustion engine characterized by being arranged so as to be directed in a tangential direction with respect to the engine.

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