JP4545053B2 - Air cleaner structure of internal combustion engine - Google Patents

Description

  The present invention relates to an air cleaner structure of an internal combustion engine having a blow-by gas reduction device that recirculates blow-by gas to an internal space of an air cleaner.

  In an internal combustion engine mounted on a motorcycle or the like, if blowby gas leaked from the combustion chamber to the internal space of the crankcase stays in the internal space of the crankcase (and its communication space), gasoline components (HC) and moisture in the gas For example, the lubricating oil in the crankcase is diluted and deteriorated. For this reason, the conventional internal combustion engine is provided with a blow-by gas reduction device for recirculating the blow-by gas to the intake side and supplying it again to the combustion chamber for combustion treatment. As this blow-by gas reduction device, for example, a configuration is known in which the outlet end of the blow-by gas recirculation passage for guiding the blow-by gas communicates with the downstream space (clean side) of the air cleaner (see, for example, Patent Document 1) ).

Japanese Utility Model Publication No. 62-42098

  However, when the blowby gas is recirculated to the downstream space of the air cleaner as in the blowby gas reduction device described in Patent Document 1, there is a risk that gasoline components and the like remaining in the recirculated blowby gas may adhere to the filter element. was there. Thereby, there existed a subject that the lifetime of a filter element became short.

  In addition, a blow-by gas reduction device has been proposed in which air is supplied from the downstream side space of the air cleaner to the communication space of the crankcase to assist the return of the blow-by gas. However, in this embodiment, blow-by gas returned to the downstream space may be returned again to the communication space of the crankcase, which may affect breathing efficiency. In order to avoid this, the configuration of the blow-by gas reduction device is complicated, for example, it is necessary to provide a dedicated filtering means for capturing contaminating components in the blow-by gas in the air supply passage to the communication space of the crankcase. There was a problem of becoming.

  In view of such problems, the present invention provides an air cleaner structure for an internal combustion engine that can improve the life of a filter element of the air cleaner in an air cleaner structure for an internal combustion engine that includes a blow-by gas reduction device that recirculates blow-by gas to the air cleaner. It is another object of the present invention to provide an air cleaner structure for an internal combustion engine that can simplify the blow-by gas reduction device.

In order to achieve the above object, an air cleaner structure of an internal combustion engine according to the present invention includes a crankcase, an intake passage that guides air to the combustion chamber, an air cleaner that is connected to the intake passage and cleans the air to the combustion chamber, In an air cleaner structure of an internal combustion engine configured to have a blow-by gas recirculation device that recirculates blow-by gas staying in the internal space of the crankcase to the intake passage, the air cleaner is partitioned from the cleaner case and the internal space of the cleaner case. The blow-by gas reducing device has one end opened to a downstream space formed by partitioning the filter element with an intake outlet provided to the cleaner case and connected to the intake passage. Blow bar communicating with the inner space of the crankcase and the other end communicating with the downstream space of the air cleaner Communicating with the gas recirculation passage, one end in the interior space of the crankcase
And the other end communicates with the downstream space to supply air to the crankcase internal space.
Part air supply passage.

And a cleaner case for guiding the air from the blow-by gas recirculation passage to the downstream space.
The blow-by gas inlet provided in the
The air from the blow-by gas recirculation passage projects from the periphery of the by-gas inlet to the downstream space.
A first rib that restricts the flow toward the filter element is provided, and the air in the downstream space is
The external air outlet provided in the cleaner case to guide it to the external air supply passage is connected to the filter air.
Arranged at a position facing the ment and overlapping the filter element in side view
And a second retainer provided on the cleaner case and extending toward the filter element.
It is comprised so that it may open to the fresh air induction | guidance | derivation space enclosed with the bush part and partitioned off from the downstream space.

When the internal combustion engine is mounted on a vehicle, the cylinder of the internal combustion engine extends in a substantially horizontal direction.
Both are arranged in a direction extending in the front-rear direction of the vehicle, and the vehicle is configured to surround the internal combustion engine.
And a blow-by gas reduction device is installed outside the external air supply passage.
It has a control valve that prevents the backflow of air flowing in the air supply passage and can adjust the flow rate.
Preferably, this control valve is attached to the frame member.

According to the configuration of the air cleaner structure of the internal combustion engine according to the present invention, the blow-by gas recirculated to the downstream space of the air cleaner flows toward the filter element by the restriction of the first rib portion provided in the air cleaner. There is no such thing. Thereby, the possibility that gasoline components and the like contained in the blow-by gas adhere to the filter element is reduced, and the life of the filter element is improved.

  In addition, the blow-by gas device is configured by having an external air supply passage for supplying air to the internal space of the crankcase, and an external air outlet for guiding the air in the downstream space of the air cleaner to the external air supply passage. The filter element is disposed at a position facing the filter element. As a result, inflow of purified air that has passed through the filter element is urged into the external air supply passage. In addition, as described above, the air from the blow-by gas recirculation passage is configured so that the flow toward the filter element is restricted. Therefore, clean air can be guided to the external air supply passage without providing a dedicated filtering means for capturing gasoline components in the blowby gas. The blow-by gas reduction device in the form of assisting can be configured without complication.

  Further, the control valve of the blow-by gas reduction device is configured to be attached to the frame member on the vehicle body side, and the configuration in which the control valve is provided at the upper part of the engine is avoided. Thereby, an internal combustion engine can be comprised compactly in the up-down direction, and the design freedom of a vehicle can be improved.

  Further, by surrounding the external air outlet with the second rib portion extending toward the filter element, cleaner air can be guided to the external air supply passage.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a left side view of a scooter type motorcycle 1 having an air cleaner structure for an internal combustion engine of the present embodiment. This scooter type motorcycle 1 is similar to a general scooter type motorcycle, a front wheel 3 attached to the front fork 2, a handle 5 connected to the front fork 2, and a unit swing type power unit PU attached to the rear part so as to be able to swing up and down. And a rear wheel 6 pivotally supported by the power unit PU.

  Further, the scooter type motorcycle 1 is configured to have a rear frame 7 extending obliquely upward with respect to the rear and provided with a substantially U-shaped rear frame 7 at the rear of the vehicle. And power unit PU is attached in the downward direction. A seat frame 9 that supports a seat seat 8 that extends horizontally with respect to the front-rear direction as shown by a two-dot chain line is attached above the rear frame 7. The rear frame 7 is provided with a cover (not shown) that is formed of a resin material or the like so as to cover the power unit PU positioned inward. Thereby, a storage space is ensured between the lower surface of the seat 8 and this cover.

  Next, the power unit PU mounted on the scooter type motorcycle 1 will be described with reference to FIGS. The engine 10 of the power unit PU is a four-cycle internal combustion engine, and includes a cylinder head cover 11, a cylinder head 12, a cylinder block 13, and a crankcase 14. The engine 10 is a horizontal cylinder type in which the cylinder head 12 is mounted so as to extend forward as shown in FIG. 2, and in the following description, the direction of the arrow U in FIG. The direction will be described as forward.

  A cylindrical cylinder sleeve 14 is fitted in the cylinder block 13, and a piston 16 is disposed in a cylinder chamber 15 formed by being surrounded by the cylinder sleeve 14 so as to be slidable in the cylinder chamber 15. ing. The piston 16 is connected via a connecting rod 17 to a crankshaft 18 that is rotatably supported in the crankcase 14. A combustion chamber 19 is formed by being surrounded by the piston 16, the cylinder head 12, and the cylinder sleeve 14. An oil pan 20 for storing lubricating oil is formed at the bottom of the crankcase 14.

  The cylinder head 12 has an intake port 21 and an exhaust port 22 formed therein. The intake port 21 extends upward in the cylinder head 12, one end communicates with the combustion chamber 19 through the intake port 23, and the other end communicates with the outside of the cylinder head 12 through the intake connection port 24. On the other hand, the exhaust port 22 extends downward in the cylinder head 12, one end communicates with the combustion chamber 19 through the exhaust port 25, and the other end communicates with the outside of the cylinder head 12 through the exhaust connection port 26.

  The cylinder head 12 has a bowl-shaped intake valve 27 and an exhaust valve 28. One end of each of the valves 27 and 28 is attached to a valve shaft and supported by a retainer, and the other end is a cylinder head. The valve springs 29 and 30 supported by the valve 12 are biased in the direction in which the intake port 23 and the exhaust port 25 are always closed.

  Further, a camshaft 31 for opening and closing the intake valve 27 and the exhaust valve 28 is rotatably supported on the cylinder head 12, and the rotation of the crankshaft 18 is transmitted by the chain mechanism 40. The chain mechanism 40 includes a drive sprocket 41 pivotally supported by the crankshaft 18, a driven sprocket 42 pivotally supported by the camshaft 31, and a cam chain 43 spanned between the two sprockets 41, 42. The camshaft 31 is rotated at half the rotational speed of the crankshaft 18. The cam chain 43 is disposed in a chain chamber 45 that communicates the internal space of the cylinder head 12 and the internal space of the crankcase 14. In the chain chamber 45, power is transmitted to the camshaft 31. A cam chain tensioner 44 for preventing the cam chain 43 from slackening is provided.

  A cam 32 corresponding to each of the intake valve 27 and the exhaust valve 28 is formed on the camshaft 31. By pushing up the rocker arm 33 by the cam 32, the respective valves 27 and 28 are pushed down and the intake port is formed. 23 and the exhaust port 25 are opened and closed.

  An inlet pipe 51 is attached to the intake connection port 24, and a carburetor 52 is attached via the inlet pipe 51. An air cleaner 80 is connected upstream of the carburetor 52 via a foldable intake pipe 53. The inlet pipe 51 is connected to the carburetor 52 and the air cleaner 80 by a cab ventilation passage 52 a for returning the fuel overflow of the carburetor 52 to the air cleaner 80.

  The air cleaner 80 is configured by disposing a filter element 83 in an internal space of a cleaner case 85 integrally formed by assembling a dirty side half body 81 and a clean side half body 82. As shown in FIG. 7 is located at the rear left side of the vehicle. The cleaner case 85 is provided with an intake inlet 81a and an intake outlet 82a that open to the outside of the vehicle. An internal space 80A of the cleaner case 85 includes an upstream space 80a in which the intake inlet 81a is opened by the filter element 83, and an intake outlet. 82a is partitioned into a downstream space 80b that is open. In addition, the intake pipe 53 is connected to the intake outlet 82 a and is connected to the air cleaner 80. The air that flows into the upstream space 80a from the intake inlet 81a passes through the filter element 83, is filtered, and flows into the downstream space 80b. The air in the downstream space 80 b that has been purified by passing through the filter element 83 is discharged from the intake outlet 82 a and is guided to the carburetor 52 through the intake pipe 53. In this way, the combustion chamber 19 is supplied with the air-fuel mixture purified by the air cleaner 80.

  The power unit PU having such an engine 10 is connected via a connecting rod 17 by causing the air-fuel mixture supplied to the combustion chamber 19 to burn with an ignition plug (not shown) to move the piston 16 up and down in the cylinder chamber 15. The crankshaft 18 is rotationally driven, and the rotation of the crankshaft 18 is changed by a belt transmission mechanism housed in the transmission case and transmitted to the rear wheel 6. During the operation of the engine 10, blow-by gas containing unburned gasoline components and moisture in the combustion chamber 19 leaks into the internal space of the crankcase 14 from between the piston 16 and the inner peripheral surface of the cylinder chamber 15. .

  The internal space of the crankcase 14 communicates with the internal space of the cylinder head 12 via the cam chain chamber 45 in which the cam chain 43 is disposed, and the blow-by gas leaking into the internal space of the crankcase 14 is Also, it stays in the internal space of the cam chain chamber 45 and the cylinder head 12. Similarly, the internal pressure of the crankcase 14 fluctuates as the piston 16 moves up and down. This internal pressure fluctuation is transmitted to the cam chain chamber 45 communicating with the internal space of the crankcase 14 and the internal space of the cylinder head 12. Hereinafter, the internal space of the crankcase 14 and its communication space (the internal space of the cam chain chamber 45 and the cylinder head 12) may be collectively referred to as a crankcase communication space 60.

  Next, the blow-by gas reduction device 90 will be described. As shown in FIG. 2, the blow-by gas reducing device 90 includes a blow-by gas recirculation passage 91 that communicates the crankcase communication space 60 and the downstream space 80 b of the air cleaner 80, and the downstream space of the crankcase communication space 60 and the air cleaner 80. A fresh air supply passage 92 communicating with 80b and a control valve 93 provided in the fresh air supply passage 92 are configured. The blow-by gas recirculation passage 91 is provided to guide air from the crankcase communication space 60 to the air cleaner 80, and the fresh air supply passage 92 is provided to guide air from the air cleaner 80 to the crankcase communication space 60.

  The blow-by gas recirculation passage 91 has an inlet end that is integrally provided with the cylinder head cover 11 and is fitted into a cylindrical connecting portion 11 a that protrudes outward, communicates with the internal space of the cylinder head cover 11, and an outlet end with the air cleaner 80. It fits into the provided cylindrical reflux side connecting portion 82d and communicates with the downstream space 80b of the air cleaner 80, and is fixed using a predetermined fixing means such as a clip. In this way, the blow-by gas recirculation passage 91 connecting the cylinder head cover 11 disposed at the front and the air cleaner 80 disposed at the left rear is in the front-rear direction so that the left side of the engine 10 is along the rear frame 7. It is extended and arranged. Further, a breather chamber 94 communicating with the internal space of the cylinder head 12 is formed inside the cylinder head cover 11. The air flowing into the breather chamber 94 is gas-liquid separated.

  The fresh air supply passage 92 includes a first supply passage 92 a upstream of the control valve 93 and a second supply passage 92 b downstream of the control valve 93. The first supply passage 92 a has an inlet end fitted into a supply side connection portion 82 e provided in the air cleaner 80 and communicates with a downstream space 80 b of the air cleaner 80, and an outlet end fitted into an upstream side connection portion 93 d of the control valve 93. Each of them is fixed using a predetermined fixing means such as a clip. The second supply passage 92 b has an inlet end fitted into the downstream connection portion 93 e of the control valve 93 and an outlet end fitted into the connection portion 95 a constituting the joint assembly 95 provided in the cylinder block 13. And are fixed using predetermined fixing means such as clips.

  As shown in FIG. 12, the joint assembly 95 includes a connecting portion 95a formed in a cylindrical shape (tubular shape) having both ends opened, and a case mounting portion 95b formed in a cylindrical shape opened downward and closed upward. The connecting portion 95a and the case attaching portion 95b are integrally formed with the cylindrical spaces 95c and 95d communicating with each other. The case mounting portion 95 b is fitted into the through hole 46 a that opens in the tensioner fixing plate 46 during the assembly process of the cam chain tensioner 44, and the cylindrical space 95 d of the case mounting portion 95 b communicates with the cam chain chamber 45. Attached. The second supply passage 92b is connected to the connection portion 95a of the joint assembly 95, and air from the first supply passage 91 and the control valve 93 is guided to the second supply passage 92b and supplied into the cam chain chamber 45. It has become so.

  The control valve 93 includes a reed valve 93a that prevents backflow and a proportional electromagnetic solenoid valve 93b that can adjust the opening degree. The reed valve 93a is provided with an upstream side connection portion 93d, and the solenoid valve 93b is provided with a downstream side connection portion 93e. The upstream side connection portion 93d and the downstream side connection portion 93e are not shown inside the case. It communicates with. The reed valve 93a is configured to have a plurality of flexible metal pieces attached so as to be able to close the conduit in the case. The reed valve 93a is closed when the internal pressure of the crankcase communication space 60 becomes positive, and becomes negative pressure. Then, it arrange | positions so that a metal piece may bend and open. The solenoid valve 93b is located on the upstream side of the reed valve 93a, is subjected to drive control by a control device (not shown), and the current value of the excitation signal from the control device that is output to the coil based on the rotational speed of the engine 1 or the like. It opens and closes at an opening according to.

  The control valve 93 is disposed on the right rear side of the vehicle and is positioned substantially symmetrically with the air cleaner 80. As shown in FIGS. 4 and 11, a mounting stay 96 is provided on the rear frame 7 so as to extend downward at a position substantially symmetrical to the arrangement position of the air cleaner 80. The control valve 93 is fixed. The first supply passage 92 a that connects the air cleaner 80 and the control valve 93 having such a positional relationship is provided behind the engine 10 and extends in the left-right direction. Further, the second supply passage 92b that connects the control valve 93 and the engine 10 disposed on the right rear side is disposed to extend in the front-rear direction.

  Thus, in the blow-by gas reduction device 90 of the present embodiment, the control valve 93 is provided on the right rear side of the vehicle, and a space for arranging the carburetor 52 above the engine 10 is secured. On the other hand, the second supply passage 92b has an outlet end connected to a connection portion 95a of a joint assembly 95 attached to the cylinder block 13, and the joint assembly 95 is disposed at a position not overlapping the carburetor 52 in the vertical direction. 4, the second supply passage 92b is connected to the joint assembly 95 so as to extend in the front-rear direction on the right side of the carburetor 52 in a plan view.

  In the blowby gas reduction device 90 having such a configuration, the piston 16 moves down in the cylinder chamber 15 so that the internal pressure of the combustion chamber 19 and the downstream space 80b of the air cleaner 80 is negative (the internal pressure of the crankcase communication space is positive). ), The blow-by gas staying in the crankcase communication space 60 is separated into gas and liquid in the breather chamber 94 and guided to the blow-by gas recirculation passage 91 from the connecting portion 11a of the cylinder head cover 11 to the downstream space 80b of the air cleaner 80. Refluxed. At this time, the reed valve 93a is closed, and blow-by gas flowing into the second supply passage 92b is not led to the first supply passage 92a and flows backward.

  Further, when the piston 16 moves up and the internal pressure of the crankcase communication space 60 becomes negative, the reed valve 93a is opened, and the air in the downstream space 80b of the air cleaner 80 is guided to the first supply passage 92a. The fluid is guided to the second supply passage 92b at a flow rate corresponding to the opening of the solenoid valve 93b and supplied to the cam chain chamber 45. The fresh air supplied to the cam chain chamber 45 assists the discharge of blow-by gas, and the breathing efficiency of the crankcase communication space 60 increases.

  Next, an air cleaner structure according to the present invention will be described with reference to FIGS. The air cleaner 80 is configured by disposing the filter element 83 in the internal space 80A of the cleaner case 85 formed from the dirty side half 81 and the clean side half 82 as described above.

  The filter element 83 is configured by fixing a substantially rectangular filter portion 83a to a packing portion 83b formed of a soft resin material such as polyurethane. The dirty side half body 81 and the clean side half body 82 are each formed in a bowl shape and assembled by engaging the mounting grooves 81c and 82c formed on the peripheral edges of each other to form an integral cleaner case 85. It is supposed to be. The dirty side half 81 is provided with an intake inlet 81a that opens downward. Further, a substantially square-shaped engagement rib 81b is provided so as to protrude from the inner wall, so that the filter portion 83a can be fitted. The clean side half 82 is provided with an intake outlet 82a that opens in a circular shape. In addition, an engagement rib 82b that can engage the packing portion 83b is formed on the inner wall.

  As shown in FIGS. 5 and 6, the dirty side half 81 is obtained by engaging the filter portion 83 a and the packing portion 83 b of the filter element 83 with the engaging ribs 81 b and 82 b of the dirty side half 81 and the clean side half 82. When the clean side half 82 is assembled, the case internal space 80A is formed by the engaging rib 81b and the filter element 83 of the dirty side half 81, and the upstream side space 80a where the intake port 81a opens and the downstream side where the intake port 82a opens. It is partitioned into a side space 80b.

  Further, as shown in FIG. 7, the clean side half 82 is formed in a cylindrical (tubular) shape having both ends opened, and a reflux side connection portion 82d to which the outlet end of the blowby gas reflux passage 91 is connected, Is formed integrally with a supply-side connection portion 82e connected to the inlet end of the fresh air supply passage 92, and is connected to the clean-side half 82 with respect to the return-side connection portion 82d. A blow-by gas inlet 82g is formed, and a fresh air supply outlet 82h of the supply side connection portion 82e is formed. Further, a connection portion 82f for attaching the cab ventilation passage 52a from the carburetor 52 is provided at a position close to the supply side connection portion 82e.

  As shown in FIG. 7, the blow-by gas inlet 82g provided in the clean-side half 82, which is the opening of the reflux-side connecting portion 82d, is located at the upper edge of the clean-side half 82 and close to the intake outlet 82a. Is provided. Further, a U-shaped rib 82j is provided in the vicinity of the blow-by gas inlet 82g so as to protrude from the inner wall of the clean-side half 82 in a substantially U shape in cross section. The periphery is enclosed by the clean side half 82 and the inner wall of the upper edge. Further, a notch 82k is provided at the tip of the U-shaped rib 82j, and the notch 82k is formed to be deviated in a direction toward the intake outlet 82a (leftward in FIG. 7). As shown in FIG. 8, the U-shaped rib 82j is provided so that the tip end portion extends in the downstream space 80b close to the inner wall of the dirty side half 81 in the assembled state of the air cleaner 80, and the downstream space 80b. A blow-by gas induction space 80c is formed in which a blow-by gas inlet 82g of the reflux side connection portion 82d is opened.

  Further, as shown in FIG. 6, the supply side connection portion 82 e is provided at a position overlapping the filter element 83 in a side view in the assembled state, and the fresh air outlet 82 h faces the filter element 83. Furthermore, an elliptical rib 82 l that protrudes in an approximately elliptical shape so as to surround the fresh air outlet 82 h from the inner wall of the clean-side half 82 is formed integrally with the clean-side half 82. 9 and 10, the elliptical rib 82l extends toward the filter portion 83a of the filter element 83 in the assembled state of the air cleaner 80, and forms a fresh air induction space 80d substantially partitioned from the downstream space 80b. To do.

  According to such an air cleaner structure of this embodiment, when the blowby gas guided by the blowby gas recirculation passage 91 flows into the air cleaner 80 from the blowby gas inlet 82g, it immediately flows into the downstream space 80b and does not diffuse. The blow-by gas guiding space 80c is guided by the U-shaped rib 82j to flow to a position close to the inner wall of the dirty side half 81, and enters the downstream space 80b from the notch 80k formed at the tip of the U-shaped rib 82j. Inflow. Here, in order for the air that has flowed to a position close to the inner wall of the dirty side half 81 to flow to the filter element 83, the air flows so as to turn back the engagement rib 81 b of the dirty side half 81. The notch 82k is directed to the intake outlet 82a adjacent to the blow-by gas inlet 82g. Thus, since the blow-by gas that has flowed into the downstream space 80b flows through the blow-by gas induction space 80c, the flow toward the filter element 83 is restricted, and from the intake outlet 82a provided in the vicinity of the recirculation-side connection portion 82d. It is guided to the intake pipe 53 and used again for combustion. For this reason, the possibility that gasoline components or the like in the blow-by gas adhere to the filter element 83 is reduced, and the life of the filter element 83 is improved.

  Further, when the crankcase communication space 60 becomes negative pressure, air from the fresh air supply passage 92 is supplied to the cam chain chamber 45. Here, the supply side connection portion 82e to which the inlet end of the first supply passage 92a is connected is provided to face the filter element 83. Further, the fresh air outlet 82h opens to a fresh air guiding space 80d substantially partitioned from the downstream space 80b by an elliptical rib 82l. Therefore, the air that has passed through the filter element 83 and has flowed into the fresh air induction space 80d flows into the first supply passage 92a. Further, as described above, the air flowing from the blow-by gas recirculation passage 91 is restricted from flowing toward the filter element 83, so that the air flowing into the first supply passage 92a contains a contaminating component in the blow-by gas. There is nothing wrong.

  For this reason, even if the blow-by gas recirculation passage 91 and the fresh air supply passage 92 are both communicated with the downstream space 80b, the fresh air supply passage 92 is dedicated for capturing gasoline components, moisture, etc. in the blow-by gas. It is not necessary to provide any filtering means, and the blow-by gas reduction device 90 can be simplified. In addition, the elliptical rib 82l provided so as to surround the fresh air outlet 82h opens the fresh air outlet 82h into the fresh air guiding space 80d partitioned from the downstream space 80b, and efficiently supplies purified air. it can.

  Further, even if the supply side connection portion 82e and the connection portion 82f of the cab ventilation passage 52a from the carburetor 52 are close to each other, gasoline components and the like flowing in from the cab ventilation passage 52a enter the first supply passage 92a. The blow-by gas reduction device 90 can be simplified and configured as described above. Thus, the air cleaner structure of the present embodiment guides the purified air guided by the fresh air guiding space 80d to the fresh air supply passage 92 regardless of the air flowing into the downstream space 80b. It is possible to improve the degree of freedom in designing the pipe connection portion that communicates with the downstream space 80b of the air cleaner 80.

  Further, a control valve 93 is attached to the rear frame 7 and is disposed at the left rear side of the vehicle. For this reason, compared with the form etc. which attach the control valve 93 to the outer upper part of the crankcase 14, the space which arrange | positions intake devices, such as the carburetor 52, can be ensured above an internal combustion engine, and it is with respect to the up-down direction of an internal combustion engine. The size can be made compact. Further, the second supply passage 92b constituting the fresh air supply passage 92 is connected to a connecting portion 95a of a joint assembly 95 communicating with the cam chain chamber. As can be seen from FIG. The engine 10 is not overlapped in the vertical direction but is disposed in different places, and an increase in size of the engine 10 in the vertical direction can be avoided. As described above, since the size of the engine 10 can be reduced in the vertical direction, a large accommodation space can be secured, and the vertical position of the seat 9 can be appropriately arranged. Can be achieved.

  The air cleaner structure of the internal combustion engine according to the present invention is not limited to the configuration of the above embodiment, and can be changed as appropriate. For example, the air cleaner structure of the internal combustion engine according to the present invention has been described as applied to a scooter type motorcycle. However, if the internal combustion engine includes an air cleaner and a blow-by gas reduction device that recirculates the blow-by gas to the air cleaner, other vehicles, etc. Even if applied to the above, the same effect can be obtained by carrying out in the same manner.

1 is a left side view of a scooter type motorcycle to which an air cleaner structure of an internal combustion engine according to the present invention is applied. It is a schematic diagram which shows the structure of an engine, an intake system, an air cleaner, and a blow-by gas reduction apparatus. It is sectional drawing of the said engine which shows a cam chain mechanism. It is the top view seen in the arrow IV direction shown in FIG. It is a top view of the air cleaner of an assembly state. It is a side view of the air cleaner of an assembly state. It is a side view which shows the inside of a clean side half body. It is sectional drawing of the air cleaner which shows a U-shaped rib and blowby gas guidance space. It is sectional drawing of the air cleaner which shows an elliptical rib and a fresh air supply path. It is sectional drawing of the air cleaner which shows an inlet_port | entrance and a fresh air supply outlet. It is a perspective view which shows a control valve. It is sectional drawing which shows a joint assembly.

Explanation of symbols

PU power unit 1 Scooter type motorcycle (vehicle)
7 Rear frame 10 Engine 14 Crankcase 19 Combustion chamber 52 Carburetor 60 Crankcase communication space 80 Air cleaner 80c Blow-by gas induction space 80d Fresh air induction space 81 Dirty side half 82 Clean side half 82a Inlet outlet 82g Blow by gas inlet 82h Fresh air Exit 82j U-shaped rib ( first rib)
82l elliptical rib (second rib part)
83 Filter element 85 Cleaner case 90 Blow-by gas reduction device 91 Blow-by gas recirculation passage 92 Fresh air supply passage (external air supply passage)
93 Control valve

Claims (2)

A crankcase, an intake passage that guides air to the combustion chamber, an air cleaner that is connected to the intake passage and cleans the air to the combustion chamber, and a blowby gas reduction device that recirculates blowby gas to the internal space of the air cleaner In an air cleaner structure of an internal combustion engine configured to have
The air cleaner is composed of a cleaner case and a filter element arranged to partition an inner space of the cleaner case, and an intake outlet provided in the cleaner case and connected to the intake passage is connected to the filter element. Open to the downstream space formed by partitioning,
The blow-by gas reduction device has a blow-by gas recirculation passage having one end communicating with the internal space of the crankcase and the other end communicating with the downstream space of the air cleaner, and one end communicating with the clutch.
The crankcase communicates with the interior space and the other end communicates with the downstream space.
An external air supply passage for supplying air to the internal space ,
A blow-by gas inlet provided in the cleaner case for guiding air from the blow-by gas recirculation passage to the downstream space is provided in the vicinity of the intake outlet,
The cleaner case protrudes from the periphery of the blow-by gas inlet to the downstream space,
A first rib for restricting air from the blow-by gas recirculation passage from flowing toward the filter element is provided ;
Provided in the cleaner case to guide the air in the downstream space to the external air supply passage.
The external air outlet is at a position facing the filter element in a side view.
The filter element is disposed at a position overlapping with the filter element, and is provided on the cleaner case.
From the downstream space surrounded by a second rib portion extending toward the filter element.
An air cleaner structure for an internal combustion engine, wherein the structure is opened to a fresh air induction space partitioned . When the internal combustion engine is mounted on a vehicle, the cylinder of the internal combustion engine is disposed in a direction extending in a substantially horizontal direction and extending in the front-rear direction of the vehicle, and a frame member constituting the vehicle surrounds the internal combustion engine. Provided,
The blow-by gas reduction device has a control valve that is interposed in the external air supply passage to prevent backflow of air flowing in the external air supply passage and can adjust the flow rate, and the control valve is the frame member The air cleaner structure for an internal combustion engine according to claim 1 , wherein the air cleaner structure is attached to the air cleaner.

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