JP2007120480A - Internal combustion engine equipped with secondary air supply device and breather device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve workability in assembling of an internal combustion engine and workability in maintenance of a secondary air supply device and a breather device by intensively arranging a valve chamber of the secondary air supply device and a breather chamber of the breather device in the internal combustion engine. <P>SOLUTION: The internal combustion engine E is equipped with a cylinder 12 to which a piston 15 is fitted, the secondary air supply device 50 for supplying air into exhaust gas, and the breather 70 for circulating blowby gas from a crank chamber 19 to an air intake passage Pi. The secondary air supply device 50 is provided with an air passage 61 formed with a pipe 60 connected to the valve chamber 53 storing a reed valve 54, and the breather device 70 is provided with a breather passage 75 formed of a pipe 74 connected to the breather chamber 72. The valve chamber 53 and the breather chamber 72 are formed in a cylinder 12 and are arranged in close contact with each other in parallel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an internal combustion engine including a secondary air supply device that supplies air into exhaust gas from a combustion chamber, and a breather device that recirculates blowby gas from a crank chamber to an intake passage.

In an internal combustion engine, it is known that a valve chamber of a reed valve device of a secondary air supply device is formed in a cylinder (see, for example, Patent Document 1). Further, it is well known that the internal combustion engine is provided with a breather device for returning the blow-by gas in the crank chamber to the intake passage.
JP 2005-127218 A

  By the way, both the valve chamber of the secondary air supply device and the breather chamber of the breather device require a conduit connected to the intake passage. Therefore, if the valve chamber and the breather chamber are arranged far apart, the conduit Piping is complicated, and it takes time and labor to connect and remove the conduit from the valve chamber and the breather chamber.

  The present invention has been made in view of such circumstances, and the invention according to claims 1 to 4 concentrates a valve chamber of a secondary air supply device and a breather chamber of a breather device in an internal combustion engine. It is an object of the present invention to improve the workability of assembling the internal combustion engine and the workability of the maintenance of the secondary air supply device and the breather device.

  According to the first aspect of the present invention, a cylinder in which a piston driven by the pressure of combustion gas generated by combustion of an air-fuel mixture in a combustion chamber is fitted, and a secondary for supplying air into exhaust gas discharged from the combustion chamber. An internal combustion engine comprising an air supply device and a breather device that recirculates blow-by gas from a crank chamber in which a crankshaft driven to rotate by the piston is housed in an intake passage, wherein the secondary air supply device includes an air amount An air passage formed by an air conduit connected to a valve chamber in which the regulating valve is accommodated is provided, and the breather device is provided with a breather passage formed by a breather conduit connected to the breather chamber, The valve chamber and the breather chamber are internal combustion engines formed in the cylinder.

  According to this, since the valve chamber of the secondary air supply device and the breather chamber of the breather device are formed in a concentrated manner in the cylinder, the valve chamber and the breather chamber are distributed and provided in separate members constituting the internal combustion engine. Compared to the case, the piping of the air conduit and the breather conduit is integrated into the cylinder and simplified, and the connection and removal work of the conduit with respect to the valve chamber and the breather chamber is facilitated.

  According to a second aspect of the present invention, in the internal combustion engine according to the first aspect, the valve chamber and the breather chamber are arranged close to each other in parallel.

  According to this, since the valve chamber and the breather chamber are arranged in close proximity to each other, the space for the other chamber is used in the form of partially utilizing the space for the one chamber of the valve chamber and the breather chamber. Is secured.

  According to a third aspect of the present invention, in the internal combustion engine according to the second aspect, the cylinder is arranged so that a cylinder axis is substantially horizontal, and the valve chamber and the breather chamber are formed on an upper side wall of the cylinder. It is.

  According to this, since the valve chamber and the breather chamber are located on the upper side wall of the cylinder, for example, it is easy to connect and remove the conduit from above the internal combustion engine mounted on the vehicle.

  According to a fourth aspect of the present invention, in the internal combustion engine according to any one of the first to third aspects, the valve chamber is disposed closer to the combustion chamber and the breather chamber is disposed closer to the crank chamber in a cylinder axial direction. The cylinder has an air supply passage for introducing air from the valve chamber into the exhaust gas closer to the combustion chamber than the valve chamber, and blow-by gas from the crank chamber closer to the crank chamber than the breather chamber. Thus, an introduction passage leading to the breather chamber is formed.

  According to this, in the cylinder, the air supply passage can be formed closer to the combustion chamber and the introduction passage can be formed closer to the crank chamber. Therefore, the length of the air passage and the length of the introduction passage can be shortened and simplified. Can be Also, since the breather chamber is in a position that is relatively difficult to be heated by combustion heat, oil mist formation due to heating is suppressed, while the valve chamber is in a position that is relatively easily heated by combustion heat. Since the exhausted air is supplied to the exhaust gas, the reactivity with the unburned components in the exhaust gas is increased.

According to invention of Claim 1, the following effect is show | played. That is, the piping of the conduit to the valve chamber and the breather chamber is simplified, and the connection and removal of the conduit are facilitated, so that the assembly work of the internal combustion engine and the maintenance work of the secondary air supply device and the breather device are facilitated. Will improve.
According to invention of Claim 2, in addition to the effect of the invention of the cited claim, there exists the following effect. That is, since the space for the valve chamber and the breather chamber can be reduced, the valve chamber and the breather chamber can be arranged in a compact manner.
According to invention of Claim 3, in addition to the effect of the invention of the cited claim, there exist the following effects. That is, since it is easy to connect and remove the conduit from the valve chamber and the breather chamber from above, the assembly workability of the internal combustion engine and the maintenance workability of the secondary air supply device and the breather device are improved.
According to invention of Claim 4, in addition to the effect of the invention of the cited claim, there exists the following effect. That is, the formation of the air supply passage and the introduction passage in the cylinder is facilitated, and the increase in size of the cylinder in the radial direction due to the formation of the air supply passage and the introduction passage is suppressed. Further, the oil separation performance in the breather chamber is improved, and the reactivity between the air and unburned components in the exhaust gas is increased, so that the exhaust gas purification performance is improved.

Hereinafter, embodiments of the present invention will be described with reference to FIGS.
Referring to FIG. 1, an internal combustion engine E to which the present invention is applied is mounted on a motorcycle B as a vehicle that is a machine in which the internal combustion engine E is used.
The motorcycle B includes a body frame 1 and a front fork that is coupled to a lower end portion of a steering shaft (not shown) rotatably supported in a head pipe 1a at a front end portion of the body frame 1 and pivotally supports a front wheel 8. 2, a handle 3 coupled to the upper end of the steering shaft, and a pivot shaft 1b provided at the lower portion of the vehicle body frame 1 so as to be swingable at the front end and pivotally supporting the rear wheel 9 at the rear end. A rear fork 4, a power unit U fixed to the vehicle body frame 1, a rear cushion 5 connected to a rear portion of the vehicle body frame 1 and a rear end portion of the rear fork 4, a vehicle body cover 6 covering the vehicle body frame 1, and a vehicle body cover 6 and an occupant seat 7 disposed at the upper end of the body cover 6a.

  The power unit U that generates power for driving the rear wheels 9 includes a horizontally disposed internal combustion engine E including a crankshaft 18 having a rotation center line L1 extending in parallel in the left-right direction (also in the vehicle width direction), and an internal combustion engine E. A gear-type transmission (not shown) for shifting the power from the crankshaft 18 of the engine E. The power from the transmission is transmitted to the rear wheel 9 via a final reduction mechanism provided with a transmission chain 10, and the rear wheel 9 is rotationally driven by the internal combustion engine E.

  Referring also to FIG. 2, an internal combustion engine E consisting of an air-cooled, single-cylinder, 4-stroke internal combustion engine includes a crankcase 11 that forms a crank chamber 19 in which a crankshaft 18 is housed, and a substantially horizontal position from the crankcase 11. A cylinder 12 that extends forward, and a cylinder head 13 and a head cover 14 that are sequentially stacked on the front end portion of the cylinder 12 and are fastened together with the cylinder 12 together with the cylinder 12 by a bolt 28.

In the cylinder 12 in which the cylinder axis L2 is disposed substantially horizontally, more specifically, in the cylinder 12 in which the cylinder axis L2 is disposed so as to extend forward from the rotation center line L1 to the cylinder head 13 substantially horizontally and slightly upward. Is provided with a cylinder hole 12c into which the piston 15 is reciprocally fitted. A crankcase 11 coupled to the rear end of the cylinder 12 and rotatably supporting the crankshaft 18 is a pair of crankcase halves divided into two with a plane perpendicular to the rotation center line L1 as a dividing plane H. This is a left-right split crankcase formed by combining 11a and 11b (see FIG. 3). The piston 15 that slides on the cylinder sleeve 16 that is integrally provided on the inner peripheral surface of the cylinder 12 is connected to the crankshaft 18 via the connecting rod 17, and the reciprocating motion of the piston 15 rotates the crankshaft 18. Converted into movement.
“Front” or “rear” is the other when one of them is a direction parallel to the cylinder axis L2 (hereinafter referred to as “cylinder axis direction”). Therefore, “front” and “rear” can be rephrased as the cylinder head side and the crankshaft side in the cylinder axial direction, respectively.

  The cylinder head 13 includes a combustion chamber 20 formed at a position facing the cylinder hole 12c in the cylinder axial direction, an intake port 21 having an intake port that opens to the combustion chamber 20, and an exhaust port that opens to the combustion chamber 20. The exhaust port 22 is formed, and an ignition plug (not shown) facing the combustion chamber 20, an intake valve 23 for opening and closing the intake port, and an exhaust valve 24 for opening and closing the exhaust port are provided.

  The intake valve 23 and the exhaust valve 24 urged in the valve closing direction by the valve spring 25 are opened and closed by a valve operating device 27 arranged in a valve operating chamber 26 formed by the cylinder head 13 and the head cover 14. The SOHC type valve gear 27 includes a cam shaft 27a that is rotatably supported by the cylinder head 13, an intake rocker arm 27d and an exhaust gas rocked by an intake cam 27b and an exhaust cam 27c provided on the cam shaft 27a, respectively. And a rocker arm 27e. The camshaft 27a is synchronized with the rotation of the crankshaft 18 at a half rotational speed by the power of the crankshaft 18 transmitted through a transmission mechanism including a timing chain provided between the camshaft 27a and the camshaft 27a. Is rotated.

The internal combustion engine E includes an intake device 30, an exhaust device 36, and a fuel injection valve 35.
An intake device 30 connected to the upper wall 13a of the cylinder head 13 where the inlet 21a of the intake port 21 opens to supply combustion air to the combustion chamber 20 includes an air cleaner 31 and a throttle connected to the downstream end of the air cleaner 31. A body 32 and an intake pipe 33 connected to the throttle body 32 at the upstream end and coupled to the upper wall 13a at the downstream end are provided. The intake air taken in by the air cleaner 31 flows through an intake passage 34 formed by an air cleaner 31 and a throttle body 32 provided with a throttle valve 32a for controlling the amount of air and an intake pipe 33, and further passes through an intake port 21. Inhaled into the combustion chamber 20. Here, the intake passage 34 formed by the intake device 30 and the intake port 21 constitute an intake passage Pi of the internal combustion engine E.

  A fuel injection valve 35 as an air-fuel mixture forming means is provided in the throttle body 32, injects fuel that forms a mixture by mixing with intake air toward the intake port 21, and supplies the fuel into the intake passage Pi. To do.

  On the other hand, an exhaust device 36 for discharging exhaust gas to the outside of the internal combustion engine E, connected to the lower wall 13b of the cylinder head 13 where the outlet 22a of the exhaust port 22 opens, is connected to an exhaust pipe 37 connected to the lower wall 13b. And an exhaust silencer 38 connected to the exhaust pipe 37. Here, the passage formed by the exhaust device 36 having the exhaust pipe 37 and the exhaust silencer 38 and the exhaust port 22 constitute an exhaust passage Pe of the internal combustion engine E.

  Then, the air-fuel mixture from the intake device 30 is drawn into the combustion chamber 20 through the intake port 21 in the intake stroke. After the air-fuel mixture in the combustion chamber 20 is compressed by the piston 15 in the compression stroke, it is ignited and burned by the spark plug, and the piston 15 driven by the pressure of the combustion gas in the expansion stroke is connected via the connecting rod 17 The crankshaft 18 is driven to rotate. The combustion gas is discharged from the combustion chamber 20 to the exhaust port 22 as exhaust gas, and further discharged to the outside through the exhaust pipe 37 and the exhaust silencer 38.

  Further, in the internal combustion engine E, a secondary air supply device 50 that supplies air into the exhaust gas in the exhaust passage Pe discharged from the combustion chamber 20 and the blow-by gas from the crank chamber 19 are recirculated to the intake passage Pi. A breather device 70 is provided.

  Referring to FIGS. 2 to 5, a secondary air supply device 50 for supplying air for purifying exhaust gas by oxidizing unburned components such as HC and CO in the exhaust gas is provided in the cylinder 12 so that the air Is provided with a valve device 51 for adjusting the flow rate. The secondary air supply device 50 is connected to the valve device 51 and the air cleaner 31 to connect the air intake passage 61 that guides the air from the air cleaner 31 to the valve device 51, and the valve device 51 and the exhaust port 22. Thus, an air supply passage 62 that guides air from the valve device 51 to the exhaust port 22 is provided. Here, the air intake passage 61 and the air supply passage 62 constitute an air passage in the secondary air supply device 50.

  The valve device 51 includes a valve housing 52 formed of a concave case portion 52a integrally formed on the upper side wall 12a of the cylinder 12, and a cover portion 52b joined to the case portion 52a by a bolt 58 and integrated. And a reed valve 54 as an air amount adjusting valve housed in a valve chamber 53 formed by the housing 52. Therefore, a part of the valve chamber 53 is formed in the cylinder 12.

  The reed valve 54 that adjusts the amount of air supplied to the exhaust gas includes a valve body 55 that is provided with a valve port 55a and is fixed to a holder 59 that is fastened together with the case portion 52a together with the cover portion 52b. A lead 56 is provided as a valve body that opens and closes the valve port 55a by contacting and separating from the valve body 55 in response to the difference, and a stopper 57 that restricts the movement of the lead 56 when the valve is opened. Since the reed 56 responds to the pulsation pressure generated in the exhaust port 22, the reed valve 54 opens when the exhaust pressure of the exhaust port 22 becomes negative, and closes when the exhaust pressure becomes positive. .

  An air intake conduit 60 (see also FIG. 1) as an air conduit that forms an air intake passage 61 that allows the air cleaner 31 and the valve chamber 53 to communicate with each other is composed of a rubber hose that is a flexible conduit, It is connected to the valve chamber 53 by being connected to the air cleaner 31 at the end and connected to the joint portion 52b1 as a connecting portion provided integrally with the cover portion 52b at the downstream end.

  An air supply passage 62 through which air having a flow rate adjusted by the reed valve 54 circulates connects the valve chamber 53 and the exhaust port 22. The air supply passage 62 formed across the cylinder 12 and the cylinder head 13 is formed of a hole formed in the cylinder 12 in parallel with the cylinder axis L2, and opens to the valve chamber 53 at the upstream end, and the cylinder at the downstream end. The first passage 62a that opens to the mating surface 12d of the cylinder head 13 and the hole formed in the cylinder head 13 has an upstream end that opens to the mating surface 13d of the cylinder head 13 with the cylinder 12 and is downstream. The first and second passages 62a and 62b are communicated with each other by a second passage 62b whose end is open to the exhaust port 22 and a groove formed on the mating surface 12d of the cylinder 12 along the periphery of the cylinder hole 12c. And a communication passage 62c. The first passage 62a and the communication passage 62c, which are the air supply passages 62 formed in the cylinder 12, allow the air from the valve chamber 53 to flow closer to the combustion chamber 20 than the valve chamber 53 or the cylinder head 13 in the cylinder axial direction. It leads to the exhaust gas of the exhaust port 22 by the side. Although not shown, the gasket interposed between the mating surfaces 12d and 13d is provided with a through hole for connecting the communication passage 62c and the second passage 62b.

  On the other hand, the breather device 70 includes a breather housing 71 that is provided in the cylinder 12 and forms a breather chamber 72 that is a volume expansion chamber that separates mist-like oil mixed in blow-by gas. The breather device 70 connects the crankcase 11 and the breather housing 71 to connect the breather housing 71 and the intake device 30 with the introduction passage 73 that guides the blow-by gas in the crank chamber 19 to the breather chamber 72. A reflux passage 75 is provided for guiding blow-by gas from the chamber 72 to the intake passage Pi. Here, the introduction passage 73 and the reflux passage 75 constitute a breather passage in the breather device 70.

  The breather housing 71 includes a concave case portion 71a formed integrally with the upper side wall 12a of the cylinder 12, and a cover portion 71b joined to the case portion 71a by a bolt 77 and integrated. Therefore, a part of the breather chamber 72 is formed in the cylinder 12.

  An introduction passage 73 formed across the crankcase 11 and the cylinder 12 to allow the crank chamber 19 and the breather chamber 72 to communicate with each other is constituted by a hole formed in one crankcase half body 11a in parallel with the cylinder axis L2. A first passage 73a that opens to the crank chamber 19 at the upstream end and opens to the mating surface 11e of the crankcase half 11a with the cylinder 12 at the downstream end, and is formed in the cylinder 12 parallel to the cylinder axis L2. The second end 73b is formed of a hole and has an upstream end opened to the first passage 73a at the mating surface 12e of the cylinder 12 with the crankcase 11 and a downstream end opened to the breather chamber 72. The second passage 73b, which is an introduction passage 73 formed in the cylinder 12, guides the blow-by gas from the crank chamber 19 to the breather chamber 72 closer to the crank chamber 19 than the breather chamber 72 in the cylinder axial direction.

  The bottom wall surface 71a1 and the introduction passage 73 of the breather chamber 72 are slightly inclined downwardly from the breather chamber 72 toward the crank chamber 19 in the cylinder axis direction, corresponding to the inclination of the cylinder axis L2. The oil separated at 72 is easily returned to the crank chamber 19.

  A recirculation conduit 74 (see also FIG. 1) as a breather conduit for forming a recirculation passage 75 that communicates the downstream portion of the intake passage Pi with respect to the throttle valve 32a and the breather chamber 72 is formed of a metal pipe, It is connected to the breather chamber 72 by being connected to a joint portion 71b1 as a connecting portion provided integrally with the cover portion 71b at the end, and connected to the throttle body 32 at the downstream end. Further, in the cover portion 71b, a plurality of partition walls 76 that form a labyrinth-like passage in the breather chamber 72 between the downstream end portion of the introduction passage 73 and the joint portion 71b1 extend downward toward the case portion 71a. Are integrally molded. The connection position of the recirculation passage 75 with the intake passage Pi may be an upstream portion of the intake passage Pi from the throttle valve 32a, for example, an air cleaner 31 (see FIG. 1).

  Referring to FIGS. 2 and 3, the valve housing 52 and the valve chamber 53 are arranged near the combustion chamber 20 or the cylinder head 13 in the cylinder 12 in the cylinder axial direction. Further, the breather housing 71 and the breather chamber 72 are disposed closer to the crank chamber 19 than the valve housing 52 and the valve chamber 53 in the cylinder axis direction, closer to the crank chamber 19 or the crankcase 11 in the cylinder 12.

In addition, the valve chamber 53 and the breather chamber 72 are arranged in close proximity to each other in the cylinder axial direction, and are arranged at positions that overlap with each other in the circumferential direction. Furthermore, the valve housing 52 or the valve chamber 53 and the breather housing 71 or the breather chamber 72 are perpendicular to the cylinder axis L2 when viewed from the up-down direction (that is, in plan view) or viewed in the radial direction. It is a long and thin shape (see FIG. 3). Further, in the cylinder axial direction, the end 52e near the cylinder head 13 of the valve housing 52 and the end 71e near the crankcase 11 of the breather housing 71 are located in the vicinity of the mating surfaces 12d and 12e, respectively.
Here, the proximity refers to the arrangement direction in which the valve chamber 53 and the breather chamber 72 are arranged in parallel to each other, in this embodiment the cylinder axial direction, and the interval between the valve chamber 53 and the breather chamber 72 is the cylinder axial direction. It means that it is smaller than the widths W1, W2 of the valve chamber 53 or the breather chamber 72 in the (arrangement direction).
In this embodiment, it is assumed that the “circumferential direction” and the “radial direction” are a circumferential direction and a radial direction around the cylinder axis L2, respectively.

  In addition, as shown in FIG. 2, the valve chamber 53 is positioned in the cylinder axis direction so as to overlap the entire piston 15 at the top dead center in the cylinder axis direction, more specifically, the top of the piston 15 at the top dead center. The surface 15a is located closer to the cylinder head 13 than the valve chamber 53, and the entirety of the piston 15 (indicated by a two-dot chain line in FIG. 2) at the bottom dead center is the cylinder head 13 or the combustion chamber. Located closer to 20. On the other hand, the breather chamber 72 is positioned so as to overlap with the bottom dead center piston 15 in the cylinder axis direction, more specifically, the top surface 15a of the bottom dead center piston 15 is located near the center of the breather chamber 72. Therefore, the valve chamber 53 is arranged so that the entirety thereof is located within the stroke range of the piston 15, and the breather chamber 72 is arranged such that a part thereof is located within the stroke range of the piston 15.

Next, operations and effects of the embodiment configured as described above will be described.
The secondary air supply device 50 is provided with an air intake passage 61 formed by an air intake conduit 60 connected to the valve chamber 53, and the breather device 70 has an introduction conduit 74 connected to the breather chamber 72. Since the introduction passage 75 to be formed is provided and the valve chamber 53 and the breather chamber 72 are formed in the cylinder 12, the valve chamber 53 and the breather chamber 72 are formed concentrated on the cylinder 12, so that the secondary air Compared with the case where the valve chamber of the supply device and the breather chamber of the breather device are provided separately in separate members constituting the internal combustion engine E, the piping of the air intake conduit 60 and the introduction conduit 74 is concentrated in the cylinder 12. This simplifies the process, and facilitates connecting / disconnecting the conduits 60, 74 to / from the valve chamber 53 and the breather chamber 72. As a result, the piping of the conduits 60 and 74 with respect to the valve chamber 53 and the breather chamber 72 is simplified, and the connection and removal of the conduits 60 and 74 are facilitated. The maintenance workability of the supply device 50 and the breather device 70 is improved.

  The valve chamber 53 and the breather chamber 72 are arranged in close proximity to each other, so that a space for one housing or chamber of the valve housing 52 or the valve chamber 53 and the breather housing 71 or the breather chamber 72 is partially formed. Space for the other housing or chamber is ensured in such a manner that it is used in an automated manner. As a result, the space for the valve chamber 53 and the breather chamber 72 can be reduced, so that the valve chamber 53 and the breather chamber 72 can be arranged in a compact manner.

  The cylinder 12 is arranged so that the cylinder axis L2 is substantially horizontal, and the valve housing 52 or the valve chamber 53 and the breather housing 71 or the breather chamber 72 are formed on the upper wall 12a of the cylinder 12, thereby The connection and removal work of the conduits 60 and 74 from above is facilitated. As a result, the connection and removal of the conduits 60 and 74 from the valve housing 52 or the valve chamber 53 and the breather housing 71 or the breather chamber 72 is facilitated with respect to the internal combustion engine E mounted on the motorcycle B. The workability of assembling the internal combustion engine E and the workability of maintenance of the secondary air supply device 50 and the breather device 70 are improved.

  In the cylinder axial direction, the valve chamber 53 is disposed closer to the combustion chamber 20 and the breather chamber 72 is disposed closer to the crank chamber 19, and the air from the valve chamber 53 is moved closer to the combustion chamber 20 than the valve chamber 53 to the cylinder 12. A first passage 62a of the air supply passage 62 that leads to the exhaust gas and a second passage 73b of the introduction passage 73 that guides the blow-by gas from the crank chamber 19 to the breather chamber 72 closer to the crank chamber 19 than the breather chamber 72 are formed. As a result, in the cylinder 12, the air supply passage 62 is formed closer to the combustion chamber 20, and the introduction passage 73 is formed closer to the crank chamber 19, so the passage length of the first passage 62a and the passage length of the second passage 73b. Since the first passage 62a and the second passage 73b in the cylinder 12 can be easily formed, and the first passage 62a and the second passage 73b are formed, the cylinder in the radial direction can be reduced. 12 increase in size Is done. Moreover, since the breather chamber 72 is in a position that is relatively difficult to be heated by combustion heat, oil mist formation due to heating is suppressed, so that the oil separation performance in the breather chamber 72 is improved, while the valve chamber 53 is Since the heated air in the valve chamber 53 is supplied to the exhaust gas because it is relatively easily heated by the combustion heat, the reactivity with the unburned components in the exhaust gas increases, and the exhaust gas Purification performance is improved.

  In the cylinder axial direction, the end 52e near the cylinder head 13 of the valve housing 52 and the end 71e near the crankcase 11 of the breather housing 71 are positioned in the vicinity of the mating surfaces 12d and 12e, and the valve housing 52 and the breather housing. By being disposed close to 71, the entire length of the cylinder 12 in the cylinder axial direction is effectively utilized, so that the secondary air supply device 50 and the breather device 70 can be efficiently installed in the cylinder 12. Provided.

Hereinafter, an embodiment in which a part of the configuration of the above-described embodiment is changed will be described with respect to the changed configuration.
Both the covers 52b and 71b may be integrally formed by a single member.
The air supply passage 62 may be constituted by an air supply conduit as an air conduit, and the introduction passage 73 may be constituted by a breather conduit.
The valve chamber 53 and the breather chamber 72 are arranged in parallel in the cylinder axial direction in the above embodiment, but may be arranged in parallel in the circumferential direction.
The air amount adjustment valve may be a check valve other than the reed valve 54 or a valve other than the check valve.
The internal combustion engine may be a multi-cylinder internal combustion engine.
In the valve device 51, the valve body 55 may be directly held by the cylinder 12 without using the holder 59.

1 is a schematic left side view of a motorcycle equipped with an internal combustion engine to which the present invention is applied. FIG. 2 is a cross-sectional view of a main part centering on an end surface on a plane including a cylinder axis and orthogonal to a rotation center line of a crankshaft in the internal combustion engine of FIG. 1. It is a figure of the principal part in the III arrow view of FIG. It is the IV-IV sectional view taken on the line of FIG. It is a figure of the cylinder in the VV arrow view of FIG.

Explanation of symbols

  11 ... Crankcase, 12 ... Cylinder, 12a ... Upper side wall, 19 ... Crank chamber, 20 ... Combustion chamber, 50 ... Secondary air supply device, 52 ... Valve housing, 53 ... Valve chamber, 70 ... Breaser device, 71 ... Breaser Housing 72 ... Breather chamber E ... Internal combustion engine.

Claims (4)

A cylinder fitted with a piston driven by the pressure of combustion gas by combustion of the air-fuel mixture in the combustion chamber, a secondary air supply device for supplying air into the exhaust gas discharged from the combustion chamber, and the piston In an internal combustion engine comprising a breather device that recirculates blow-by gas from a crank chamber in which a rotationally driven crankshaft is housed to an intake passage,
The secondary air supply device is provided with an air passage formed by an air conduit connected to a valve chamber in which an air amount adjusting valve is accommodated, and the breather device includes a breather chamber connected to the breather chamber. An internal combustion engine comprising a breather passage formed by a conduit, wherein the valve chamber and the breather chamber are formed in the cylinder.   The internal combustion engine according to claim 1, wherein the valve chamber and the breather chamber are arranged close to each other in parallel.   The internal combustion engine according to claim 2, wherein the cylinder is arranged so that a cylinder axis is substantially horizontal, and the valve chamber and the breather chamber are formed on an upper side wall of the cylinder. The valve chamber is disposed closer to the combustion chamber, the breather chamber is disposed closer to the crank chamber, and air from the valve chamber is placed closer to the combustion chamber than the valve chamber. 4. An air supply passage that leads into exhaust gas and an introduction passage that leads blow-by gas from the crank chamber to the breather chamber closer to the crank chamber than the breather chamber is formed. An internal combustion engine according to claim 1.

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