JP4636508B2 - Reed valve arrangement structure of internal combustion engine - Google Patents

Description

  The present invention relates to a secondary air supply device that purifies exhaust gas from an internal combustion engine, and more particularly, to an arrangement structure of a reed valve for supplying secondary air.

  In order to prevent the unburned components contained in the exhaust gas of the internal combustion engine from being released into the atmosphere as they are, secondary air is supplied from the air cleaner to the exhaust passage, and the unburned components are burned to purify the exhaust. Secondary air supply devices are known.

In particular, there is an example in which a secondary air passage is formed in the outer periphery of a cylinder head and a cylinder head cover (see Patent Document 1).
Japanese Patent No. 26677782

In Patent Document 1, a valve storage chamber is formed on the exhaust port side of a secondary air passage provided in the outer periphery of the cylinder head and the cylinder head cover, and a reed valve is disposed in the valve storage chamber.
The upstream side of the reed valve in the valve storage chamber communicates with the secondary air passage, and the downstream side of the reed valve communicates with the exhaust passage through the communicating passage.

  Therefore, the reed valve opens and closes due to the pulsation of the exhaust pressure in the exhaust passage, secondary air is introduced from the air cleaner through the secondary air passage to the exhaust passage, and unburned components contained in the exhaust gas are burned, and the exhaust is discharged. Can be purified.

  In the secondary air supply device disclosed in Patent Document 1, a valve storage chamber in which a reed valve is disposed is formed in a secondary air passage provided in the outer peripheral portion of the cylinder head and the cylinder head cover. And the cylinder head cover becomes larger.

  Further, the purification rate improves as the secondary air is introduced into the higher temperature exhaust gas. However, in Patent Document 1, the reed valve is located at the outer peripheral portion away from the center of the cylinder head and the cylinder head cover. Because the valve storage chamber communicates with the exhaust passage away from the combustion chamber, the secondary air is introduced to a place where the exhaust temperature is somewhat lowered, and so high purification performance is expected. Can not.

  The present invention has been made in view of the above points, and an object of the present invention is to lead an internal combustion engine capable of avoiding an increase in size of a cylinder head portion and a cylinder head cover provided with a reed valve and improving purification performance. The valve arrangement structure is provided.

In order to achieve the above object, the invention described in claim 1 comprises a secondary air supply device (230), wherein the camshaft (161r) of the valve train is disposed on the crankcase (22) side, In the OHV type internal combustion engine in which the intake valve (101r) and the exhaust valve (102r) on the cylinder head (24r) are operated via the push rod (153r, 157r) by the rotation of the (161r) , the intake valve (101r ) On the intake port (103r) side, and the exhaust valve (102r) on the exhaust port (104r) side tilts symmetrically with respect to the cylinder axis and moves obliquely with respect to the cylinder axis to open and close the valve. An intake rocker arm shaft (150r) and an exhaust rocker arm shaft (155r) are provided so as to be oriented in directions orthogonal to the moving directions of the intake valve (101r) and the exhaust valve (102r), The intake valve and exhaust valve are Are respectively each opened and closed by swinging of the axially supported by the intake rocker arm and exhaust rocker arm to preparative an exhaust rocker arm shaft, reed valve (232) actuated by the pulsation of exhaust pressure in the secondary air supply device (230), said intake there between the rocker arm shaft (150 r) and said intake valve (101 r) and the exhaust valve cylinder head above the combustion chamber (105r) is (24Ra) supporting between the exhaust rocker arm shaft (155r) (102r) The reed valve arrangement structure of the internal combustion engine is sandwiched between the cylinder head portion and the cylinder head cover (26r) fixed to be overlapped with the upper surface of the cylinder head portion (24ra).

  The invention according to claim 2 is the reed valve arrangement structure of the internal combustion engine according to claim 1, wherein the internal combustion engine is obliquely inserted into the cylinder head (24r) and faces a combustion chamber (105r). Plugs (117r, 117r) are provided, and the reed valve is disposed in a region surrounded by the intake valve (101r), the exhaust valve (102r), and the plurality of spark plugs (117r, 117r). .

According to the reed valve arrangement structure for an internal combustion engine according to claim 1, in the internal combustion engine, the camshaft of the valve operating system is arranged on the crankcase side, and the camshaft rotates on the cylinder head via the push rod. Since it is an OHV type internal combustion engine in which the intake valve and exhaust valve are operated, there is no camshaft above the cylinder head, so the cylinder head and cylinder head cover can be made smaller, and the reed valve layout space is secured. Easy to do.
Since the reed valve is located between the intake valve and the exhaust valve supported by the cylinder head portion above the combustion chamber and is sandwiched between the cylinder head portion and the cylinder head cover, the space between the intake valve and the exhaust valve is And the use of dead space between the intake and exhaust rocker arm shafts, the reed valve can be arranged to prevent the cylinder head and cylinder head cover from becoming large, and the cylinder head and cylinder head cover can be avoided. The reed valve is located at a position near the combustion chamber in the center of the exhaust gas, so that secondary air can be introduced into a high temperature portion of the exhaust gas near the combustion chamber in the exhaust passage, so that purification performance can be improved.

  According to the reed valve arrangement structure for an internal combustion engine according to claim 2, the reed valve is disposed in a region surrounded by the intake valve, the exhaust valve, and the plurality of spark plugs. However, it is possible to avoid an increase in the size of the cylinder head portion and the cylinder head cover.

Hereinafter, an embodiment according to the present invention will be described with reference to FIGS.
FIG. 1 is an overall side view of a motorcycle 1 equipped with an internal combustion engine 20 according to the present embodiment.

In the motorcycle 1, a main frame 3 extends from a head pipe 2, and a down tube 4 extends in a bifurcated manner downward. The down tube 4 is bent at the lower end and extends rearward.
A radiator 38 is supported between the down tubes 4.
The rear end of the main frame 3 divided into two parts and the rear end of the down tube 4 are connected by a pair of left and right pivot frames 5.

A front fork 7 that is pivotally supported by the head pipe 2 and extends upward and is rotated by a handle 6 that expands to the left and right extends downward, and a front wheel 8 is pivotally supported at the tip thereof.
A rear wheel 11 is pivotally supported at the rear end of a rear fork 10 that is pivotally supported by a pivot shaft 9 and pivotable up and down.

  A rear cushion 13 is interposed between a bracket 12 provided on the main frame 3 and a rear fork 10 that swings up and down.

  The internal combustion engine 20 is mounted in a space surrounded by the main frame 3, the down tube 4, and the center frame 5. The countershaft 67 protrudes to the left from the transmission case 27 behind the crankcase 22 of the internal combustion engine 20. A drive shaft 16 is connected to the drive gear 14 fitted to the rear wheel 11 and the driven gear 15 fitted to the rear axle integral with the rear wheel 11 so that power is transmitted to the rear wheel 11.

  A fuel tank 17 is supported so as to straddle the main frame 3, and a rear fender 18 extending rearward from the upper part of the center frame 5 covers the upper part of the rear wheel 11, and between the fuel tank 17 and the rear fender 18 and above the rear fender 18. A seat 19 is provided.

  The internal combustion engine 20 is a front / rear V-type two-cylinder water-cooled four-stroke cycle internal combustion engine in which a crankshaft 21 is mounted horizontally and horizontally oriented with respect to a vehicle body, and cylinders are banked in front and rear in a V shape. is there.

The front / rear V-type two-cylinder internal combustion engine 20 has a front bank cylinder 23f and a rear bank cylinder 23r extending obliquely upward from a crankcase 22, and cylinder heads 24f and 24r overlaid thereon, and a rocker arm thereon. Cylinder head covers 26f and 26r are put on the holders 25f and 25r, respectively.
Water jackets 23fw and 23rw are formed around the cylinder bores of the front bank cylinder 23f and the rear bank cylinder 23r.

Referring to FIG. 4, the rear of the crankcase 22 is partitioned by a partition wall 22a and a transmission case 27 is integrally formed. The crankcase 22 and the transmission case 27 are divided into left and right parts, and the right crankcase A clutch / gear case 28 is attached to the right of the 22 and the mission case 27.
The clutch / gear case 28 has an opening opened rightward on the rear transmission case side, and the clutch cover 29 covers the opening.

  Accordingly, the crankcase 22C is defined by the crankcase 22 and the partition wall 22a, and the mission chamber 27C is defined by the transmission case 27 and the partition wall 22a. The crankcase 22 and the transmission case 27 are partitioned into the clutch / gearcase 28. The clutch chamber 28C is formed by being covered with the clutch cover 29.

  The chain cover 30 covers the right side of the front side wall of the clutch / gear case 28, the left side of the left crank case 22 is covered with the side cover 36 (see FIG. 1) and the ACG cover 31, and the left transmission case 27 The clutch drive mechanism cover 33 covers the left side.

  In the front and rear V-type internal combustion engine 20, the center axes of the front bank cylinder 23f and the rear bank cylinder 23r are on the same plane orthogonal to the crankshaft 21, and are not offset in the left-right width direction.

  A small end is connected to the front connecting rod 41 having a small end connected to the piston pin 40fp of the piston 40f reciprocating in the front bank cylinder 23f and a piston pin 40rp of the piston 40r reciprocating in the rear bank cylinder 23r. The rear connecting rod 45 is connected at its large end to a common crank pin 21p that connects the pair of crank webs 21w, 21w of the crankshaft 21.

  As shown in FIG. 9, the front connecting rod 41 has a small end portion 41s integrally formed at one end, and has a split structure in which the large end portion 41b at the other end is divided into two by a plane perpendicular to the rod axis. A semi-arc-shaped connecting rod cap 42 is fitted to the semi-arc-shaped main body side large end portion 41bh with the crank pin 21p interposed therebetween, and both ends are fastened by connecting rod bolts 43.

  On the other hand, as shown in FIGS. 10 to 12, the rear connecting rod 45 has the same small end 45s at one end, but the large end at the other end is bifurcated and opposed. And a split structure that is split in two on a plane perpendicular to the rod axis.

  That is, the pair of large end portions 45b, 45b is a pair of semicircular arc large end halves 46bc, 46bc with respect to the pair of bifurcated semicircular rod body side large end half bodies 45bh, 45bh. Are connected to each other by connecting rod caps 46 that project from each central portion outward (centrifugal direction) and are connected to each other by connecting projections 46c to form four corners on both sides of connecting projections 46c. Are connected by connecting rod bolts 47.

The pair of large end portions 45b and 45b of the rear connecting rod 45 sandwich the large end portion 41b of the front connecting rod 41 and are pivotally supported by the crank pin 21p on both sides of the large end portion 41b (see FIG. 4). .
In the rear connecting rod 45, a connecting projection 46c of a connecting rod cap 46 constituting a pair of large end portions 45b, 45b particularly protrudes downward (see FIGS. 2 and 8).

  Thus, one large end portion 41b of the front connecting rod 41 and a pair of large end portions 45b, 45b of the rear connecting rod 45 have a pair of large end portions 45b, 45b with the large end portion 41b in the center. Coupling vibration is prevented because it is pivotally supported by the same crank pin 21p located on both sides.

  The pair of large end portions 45b, 45b of the rear connecting rod 45 are assembled such that the connecting projection 46c of the connecting rod cap 46 straddles the connecting rod cap 42 of the other front connecting rod 41, and both interfere with each other. There is no such thing.

  Further, since the cylinder central axes of the front bank cylinder 23f and the rear bank cylinder 23r are on the same plane orthogonal to the crankshaft 21 and are not offset in the left-right width direction, the left-right width length of the internal combustion engine 20 is reduced. be able to.

  The crankshaft 21 connected to the front connecting rod 41 and the rear connecting rod 45 by a common crankpin 21p and driven to rotate is pivotally supported on the left and right crankcases 22 via bearings 35 and 35.

A sleeve 50 is fitted to a portion of the crankshaft 21 that protrudes to the clutch chamber 28C on the right side, and a cap 51 having a drive sprocket 52 is put on the tip and fixed integrally with a bolt 53.
The tip of the cap 51 including the drive sprocket 52 protrudes rightward from the opening of the clutch / gear case 28.

A primary gear 55 is pivotally supported on the sleeve 50, and the rotation of the crankshaft 21 is transmitted via a damper mechanism 56.
An AC generator 57 is provided at a portion of the crankshaft 21 that projects leftward from the left crankcase 22, and a driven gear 58 of a starting mechanism is provided via a one-way clutch 59.

  The balancer shafts 60 and 61 for canceling the primary vibration are disposed in parallel on the same horizontal plane as the crankshaft 21 at a symmetrical position of the crankshaft 21 to constitute a biaxial balancer mechanism.

The front balancer shaft 60 is rotatably supported on the left and right crankcases 22 and 22 via bearings 62 and 62 (see FIG. 5), and the rear balancer shaft 61 is rotatable via bearings 63 and 63. It is pivotally supported (see FIG. 4).
The balancer weights 60w and 61w of the front and rear balancer shafts 60 and 61 pivot between the pair of crank webs 21w and 21w of the crankshaft 21.

  The balancer shafts 60 and 61 pass through bearings 62 and 63 that are pivotally supported on the right crankcase 22 and protrude into the clutch chamber 28C. Balancer gears 64 and 65 are fitted to the right protruding ends of the balancer gears 64. , 65 mesh with the primary gear 55 of the same diameter provided on the crankshaft 21, and the balancer shafts 60, 61 rotate in reverse at the same rotational speed in conjunction with the rotation of the crankshaft 21.

  A main shaft 66 and a countershaft 67 are pivotally supported by the transmission case 27 behind the rear balancer shaft 61.

  A counter shaft 67 disposed obliquely above and behind the main shaft 66 is pivotally supported at both ends by the left and right transmission cases 27 via bearings, and a shift shift mechanism 75 is disposed above the main shaft 66.

  A drive gear 14 is fitted to the left end of the countershaft 67 protruding from the mission chamber 27C.

A multi-plate clutch 77 is provided at the right end of the main shaft 66 protruding outside the transmission chamber 27C, and a main gear 78 provided integrally with a clutch housing 77h rotatably supported by the main shaft 66 of the multi-plate clutch 77. The rear balancer shaft 61 is meshed with the balancer gear 65.
The main gear 78 is integrally formed with an oil pump gear 79.

  The clutch operating shaft 81 passes through the center hole of the main shaft 66, the right end thereof is connected to the pressure plate 77p of the multi-plate clutch 77, and the left end is incorporated in the clutch drive mechanism 82 provided in the clutch drive mechanism cover 33. It is.

  Therefore, when the crankshaft 21 is rotated by the operation of the internal combustion engine 20, the primary gear 55 is rotated via the damper mechanism 56, and the rotation of the primary gear 55 is rotated by the balancer gears 64, 65 before and after meshing with the primary gear 55. The shafts 60 and 61 are rotated.

  The balancer gear 65 of the rear balancer shaft 61 is rotated by rotating the main gear 78 meshing with the balancer gear 65 together with the clutch housing 77h of the multi-plate clutch 77 and rotating the main shaft 66 through the engagement of the multi-plate clutch 77. .

  As for the rotation of the main shaft 66, any one of the meshing gears corresponding to the main gear train and the counter gear train is selectively enabled by the shift shift mechanism 75 to rotate the counter shaft 67. The rear wheel 11 rotates together with the drive gear 14 that is integrally fitted, and the rear wheel 11 is rotated via a drive shaft 16 that connects the drive gear 14 and the driven gear 15.

In the mission chamber 27C, an oil pump 85 is disposed in front of the main shaft 66 obliquely below (see FIG. 2).
As shown in FIG. 6, the oil pump 85 is composed of three pumps, a crank chamber scavenging pump 86, a feed pump 87, and a clutch chamber scavenging pump 88 in order from the left, and has a common rotating shaft 89 oriented in the left-right direction. Each inner rotor is fitted and provided.

  A bearing portion 88cb formed at the center of the right side wall of the pump case 88c of the right clutch chamber scavenging pump 88 protrudes and is inserted into the circular hole of the right mission case 27, and the rotary shaft 89 passes through the bearing portion 88cb to engage the clutch. The pump drive gear 90 is fixed to the projecting portion of the rotary shaft 89 by a bolt 91, and the pump drive gear 90 meshes with the oil pump gear 79.

  Therefore, when the rotation of the crankshaft 21 is transmitted to the primary gear 55, the balancer gear 65, and the main gear 78 and the oil pump driving gear 79 that is integral with the main gear 78 is rotated, the pump driving gear 90 that meshes with the gear rotates. The oil pump 85 is driven.

  The bearing portion 88cb inserted into the circular hole of the right mission case 27 from the mission chamber 27C side has an oil seal 92 interposed between the circular hole and the gap between the mission chamber 27C and the clutch chamber 28C. Sealed (see FIG. 6).

  On the other hand, a starter motor 95 is disposed behind the mating portion with the rear bank cylinder 23r of the crankcase 22 so that the drive shaft 96 protrudes to the left, and is formed on the drive shaft 96 as shown in FIG. The large-diameter gear 97b of the reduction gear shaft 97 meshes with the driven gear 96g, the large-diameter intermediate gear 98b of the intermediate shaft 98 meshes with the small-diameter gear 97s of the reduction gear shaft 97, and the small-diameter intermediate gear of the intermediate shaft 98 98s meshes with the driven gear 58 of the crankshaft 21.

  Accordingly, the rotation of the starter motor 95 is sequentially transmitted to the drive gear 96g, the large diameter gear 97b, the small diameter gear 97s, the large diameter intermediate gear 98b, the small diameter intermediate gear 98s, and the driven gear 58, and the crankshaft 21 is transmitted via the one-way clutch 59. The internal combustion engine 20 can be started by rotational driving.

Next, the intake / exhaust system will be described.
The internal combustion engine 20 is an OHV type internal combustion engine, and intake valves 101f and 101r and exhaust valves 102f and 102r are provided in cylinder heads 24f and 24r, but a valve operating cam mechanism is provided in the right crankcase 22. ing.

  The intake valves 101f and 101r and the exhaust valves 102f and 102r are provided so that the intake ports 103f and 103r of the cylinder heads 24f and 24r and the openings of the exhaust ports 104f and 104r to the combustion chambers 105f and 105r can be opened and closed.

As shown in FIG. 4, two ignition plugs 117r and 117r are inserted into the left and right in the combustion chamber 105r of the rear cylinder head 24r.
Similarly, for the front cylinder head 24f, although not shown, two spark plugs are fitted into the combustion chamber 105f.

In the front cylinder head 24f, the intake port 103f extends rearward from the combustion chamber 105f and is connected to the intake pipe 110f between the V banks (see FIG. 2), and the exhaust port 104f extends forward obliquely rightward from the combustion chamber 105f. To the exhaust pipe 115 (see FIG. 1).
On the other hand, in the rear cylinder head 24r, the intake port 103r extends forward from the combustion chamber 105r and is connected to the intake pipe 110r between the V banks (see FIG. 2), and the exhaust port 104r is inclined rearward and rightward from the combustion chamber 105r. It extends in the direction and is connected to the exhaust pipe 116 (see FIG. 1).

  As shown in FIG. 7, an intake pipe 110f extending rearward from the front cylinder head 24f and an intake pipe 110r extending forward from the rear cylinder head 24r are combined at the center and extend rightward. This is a branch pipe of the intake pipe 110 integrally formed with the upstream intake pipe 110c.

A throttle body 120 is connected to an upstream side intake pipe 110c that extends to the right of the intake pipe 110, and an air cleaner 130 is disposed upstream of the right side of the throttle body 120.
The air cleaner 130 is disposed so as to cover the space between the V banks from the right side along the right side surfaces of the cylinders 23f and 23r, the cylinder heads 24f and 24r, and the cylinder head covers 26f and 26r before and after the V bank.

Fuel injection valves 111f and 111r are attached to the intake pipes 110f and 110r branched before and after the intake pipe 110 so as to project obliquely upward, and the upper ends of the fuel injection valves 111f and 111r are fitted into one common socket 112. is doing.
A connecting pipe 113 to which a fuel pipe is connected projects from the socket 112 to the left.

On the other hand, the exhaust pipe 115 extending diagonally forward and rightward from the front cylinder head 24f bends and extends downward as shown in FIG. 1 and then bends rearward along the right side surface of the crankcase 22, It is connected to a muffler 115m disposed on the right side of the rear wheel 11 in the longitudinal direction.
Further, the exhaust pipe 116 extending rearward from the rear cylinder head 24r is bent downward and then bent rearward along the right side surface of the transmission case 27, and the muffler 115m is disposed on the right side of the rear wheel 11. It is connected to a muffler 116m arranged in parallel on the top.

Next, the mechanism of the valve train will be described.
Referring to FIG. 3 which is a top view of the rear cylinder head portion 24ra, the rocker arm holder 25r stacked on the cylinder head 24r constituting the intake / exhaust system as described above has an intake system rocker arm shaft 150r and an exhaust gas respectively. The system rocker arm shaft 155r is rotatably held in the cylinder head cover 26r.

Referring to FIGS. 3 and 4, a rocker arm 151r that operates the intake valve 101r and a rocker arm 152r that is operated by an intake system push rod 153r are fitted to the intake system rocker arm shaft 150r that is inside the V bank. .
Similarly, a rocker arm 156r that operates the exhaust valve 102r and a rocker arm 157r that is operated by an exhaust system push rod 158r are fitted to the exhaust system rocker arm shaft 155r that is outside the V bank.

  The intake system push rod 153r and the exhaust system push rod 158r have upper ends that are in contact with the rocker arm 152r and the rocker arm 157r in the cylinder head cover 26r, but the lower ends thereof are valve trains in the clutch / gear case 28 provided in the right crankcase 22. The long part excluding the upper and lower ends is connected to the cam mechanism 160 and is outside along the right side surface of the cylinder 23r and the cylinder head 24r.

Thus, the main valve mechanism uses the OHV system, and the valve cam mechanism 160 is provided on the crankcase 22 side, and the intake valve 101r provided on the cylinder head 24r via the push rods 153r and 158r. And the exhaust valve 102r is driven.
The front cylinder head 24f has the same structure.

  The valve-operating cam mechanism 160 in the clutch / gear case 28 has a camshaft 161r (a front bank camshaft is not shown in the figure) obliquely forward and rearward of the right end of the crankshaft 21 so as to be rotatable in parallel with the crankshaft 21. It is supported.

  Referring to FIG. 4, rear bank camshaft 161r penetrates the side wall of clutch / gear case 28 and protrudes to the right, and driven sprocket 162r is fitted to the protruding end of clutch / gear case 28. A chain 163 is wound around a drive sprocket 52 fixed to the tip of a cap 51 that covers a crankshaft 21 that protrudes to the right from the opening, and a driven sprocket 162r obliquely upward and forward.

  The driven sprocket 162r has twice as many teeth as the drive sprocket 52. Therefore, the rotation of the crankshaft 21 is transmitted from the drive sprocket 52 to the driven sprocket 162r via the chain 163, and the driven sprocket 162r is a rear bank cam. The shaft 161r rotates at half the rotational speed of the crankshaft 21.

  Referring to FIG. 4, the rear bank camshaft 161r has two pairs, one pair for intake and one pair for exhaust, in which a high-speed cam and a low-speed cam are adjacent to each other. The four rocker arms 164r are in contact with each other, and the four rocker arms 164r are pivotally supported on a common rocker arm shaft 165r, and the rollers of the high-speed rocker arms 164r and 164r are pressed against the cam by the elastic biasing means 166r. ing.

  A hydraulic passage is formed in the rocker arm shaft 165r, and hydraulic pressure can be applied to an engagement / disengagement mechanism formed between the high speed rocker arm 164r and the low speed rocker arm 164r corresponding to the high speed cam and the low speed cam. The swing end receives the lower ends of the intake system push rod 153r and the exhaust system push rod 158r.

  Therefore, when no hydraulic pressure is applied to the engagement / disengagement mechanism, the high-speed rocker arm 164r and the low-speed rocker arm 164r detach and swing independently of each other, and the intake system push rod 153r received at the tip of the low-speed rocker arm 164r and the exhaust system The push rod 158r moves up and down according to the low speed cam, and the intake valve 101r and the exhaust valve 102r operate at the low speed valve timing.

  On the other hand, when hydraulic pressure acts on the engagement / disengagement mechanism, the high-speed rocker arm 164r and the low-speed rocker arm 164r engage and swing together, and the intake system push rod 153r received at the tip of the low-speed rocker arm 164r and the exhaust The system push rod 158r moves up and down according to the high-speed cam, and the intake valve 101r and the exhaust valve 102r operate at high-speed valve timing.

  The front bank camshaft is also similar to the rear bank camshaft 161r in the same direction as the four rocker arms, rocker arm shafts, and the elastic urging means together with the intake system push rod and the exhaust system push rod. In the structure, the intake valve 101f and the exhaust valve 102f operate at a low speed valve timing when no hydraulic pressure acts on the engagement / disengagement mechanism, and operate at a high speed valve timing when the hydraulic pressure acts on the engagement / disengagement mechanism.

A hydraulic control valve 168 for controlling the hydraulic pressure to the engagement / disengagement mechanism is attached to the left extension portion of the front balancer shaft 60 on the side wall of the left crankcase 22 (see FIG. 5).
The hydraulic control valve 168 attached to the same portion of the left crankcase 22 is covered by the side cover 36 (see FIG. 1).

Next, the lubrication system will be described.
As shown in FIG. 8, the crank chamber 22C in which the left and right crank webs 21w, 21w of the crankshaft 21 and the connecting projections 46c of the large end portions 45b, 45b of the rear connecting rod 45 are pivoted is shown in FIG. An arc-shaped oil reservoir 170 is formed at the bottom of the case 22 along the trajectory of the maximum diameter of the connecting protrusion 46c. The oil outlet 171 opens rearward adjacent to the oil reservoir 170, and the oil reservoir It communicates with a small oil chamber 172 adjacent to the rear of 170.

In the oil discharge port 171, a part of the bottom wall of the oil reservoir 170 protrudes into the small oil chamber 172 slightly obliquely upward to form a discharge guide rib 171 a, and the rear portion along the bottom surface of the small oil chamber 172 The outlet A1a is open.
The oil is prevented from returning from the small oil chamber 172 to the oil reservoir 170 by the discharge guide rib 171a protruding into the small oil chamber 172.

  The outlet A1a is an opening of the communication oil passage A1 communicating with the oil pipe A2 piped in the mission chamber 27C, and the oil pipe A2 is an intake through which oil is sucked into the crank chamber scavenging pump 86 of the oil pump 85. It communicates with oil passage A3.

  As shown in FIG. 8, when the movement of the connecting projection 46c of the large end portions 45b and 45b of the rear connecting rod 45 is seen, the connecting projection near the bottom dead center of the piston 40r of the rear bank cylinder 23r tilted rearward. 46c is immersed in the oil accumulated in the oil reservoir 170 from the front, and then pivoted toward the rear oil discharge port 171, so that reference is made to the connecting projections 46c ′ and 46c ″ shown by the two-dot chain line in FIG. The connecting protrusion 46c has an effective movement in which the flat surface of the rear face 46cb pushes the oil accumulated in the oil reservoir 170 and scrapes it out to the oil discharge port 171 (the surface of the oil at the time of the connecting protrusion 46c ′ in FIG. 8). In this case, the oil can be efficiently discharged from the oil reservoir 170 to the small oil chamber 172.

It should be noted that the connecting protrusion 46c that scrapes the oil in the oil reservoir 170 is provided on the large ends 45b and 45b of the rear connecting rod 45 rather than on the front connecting rod 41, as shown in FIG. The oil can be discharged more efficiently by performing a more effective movement by scraping the oil to the oil discharge port 171.
Further, the rear surface 46cb of the connecting projection 46c may be formed as a concave surface so as to increase the amount of oil that is scraped once.

  Since the large end portions 45b and 45b of the rear connecting rod 45 have a split structure that is divided into two by a plane perpendicular to the rod axis, the pair of semicircular arc large end halves 46bc and 46bc of the connecting rod cap 46 are It can be formed integrally, and processing and assembly can be facilitated.

  Further, the pair of semicircular arc large end halves 46bc and 46bc of the connecting rod cap 46 are aligned with the rod main body side large end half parts 45bh and 45bh, and the four corners on both sides of the connecting projection 46c are connected by connecting rod bolts 47. Since the large end portions 45b and 45b are formed by fastening, the shape of the connecting projection portion 46c is not restricted by the connecting rod bolt 47, and has a high degree of freedom and easily forms a shape that can scrape out the oil efficiently. can do.

  Thus, the oil accumulated in the oil reservoir 170 of the crank chamber 22C is discharged from the oil discharge port 171 to the small oil chamber 172 by the scraping of the connecting projection 46c of the rear connecting rod 45, and is discharged to the small oil chamber 172. The oil is led from the outlet A1a to the communication oil path A1, and is sucked into the left crank chamber scavenging pump 86 of the oil pump 85 through the oil pipe A2 and the suction oil path A3 (see FIG. 2).

  A discharge pipe 175 extends upward from the crank chamber scavenging pump 86, and oil discharged by the crank chamber scavenging pump 86 is engaged with the main gear train 72 and the counter gear train 73 in the transmission chamber 27C through the discharge pipe 175. To be sprayed.

  2 and 5, an oil passage B1 extending from the lower side of the primary gear 55 to the rear side of the rear balancer gear 65 is formed in the bottom wall of the clutch / gear case 28. The passage B1 is connected to the clutch chamber 28C by opening a communication port B1a near the lower portion of the primary gear 55, and the rear end of the oil passage B1 bulges into the clutch chamber 28C (not shown). The suction oil passage is connected to the clutch chamber scavenging pump 88 on the right side of the oil pump 85 through the strainer (see FIG. 6).

  Therefore, when the clutch chamber scavenging pump 88 is operated, the oil in the clutch chamber 28C passes through the oil passage B1 and is sucked through the strainer.

Referring to FIGS. 2 and 6, the oil accumulated at the bottom of mission chamber 27 </ b> C is sucked from suction pipe C <b> 1 through a strainer 185 by a central feed pump 87 in oil pump 85.
Then, oil is discharged from the feed pump 87 into the discharge oil passage C2, and the discharge oil passage C2 is coupled to the inlet of the oil filter 186 attached to the lower rear portion of the transmission case 27. The oil filter 186 is connected to the main gallery M. To be leaked.

  The main gallery M communicates with the main oil passage M2 extending forward from the oil filter 186 into the small oil chamber 172 adjacent to the rear of the crank chamber 22C and directed in the left-right direction. The main oil passages M3 and M3 are bent at the left and right ends of the oil passage M2 so that the side walls of the left and right crankcases 22 extend in the front-rear direction, and extend upward from the middle of the main oil passages M3 and M3 extending forward. The branched oil passages D1 and D1 supply oil to the left and right journal portions of the crankshaft 21 (see FIGS. 2 and 5).

  Referring to FIG. 2, the main oil passage M3 extending forward through the left crankcase 22 extends upward at the front end past the branch of the oil passage D1, and then bends forward to reach the hydraulic control valve 168. It communicates with passage E1.

From the hydraulic control valve 168, an oil passage F1 is formed with the left crankcase 22 facing the right front balancer shaft 60 (see FIG. 5), and an oil passage E2 is formed upward (see FIG. 5). 2).
The hydraulic control valve 168 can switch between sending the pressure oil flowing in from the oil passage E1 to the oil passage E2 going upward or flowing out to the oil passage F1 going to the front balancer shaft 60.

  The oil passage E2 extending upward becomes an oil passage E3 that is bent rightward at the upper end and extends to the right crankcase 22, and the oil passage E3 is obliquely rearward on the side wall of the right crankcase 22 with reference to FIG. The oil passage E4 is bent horizontally upward and then extends horizontally, and the oil passage E4 is bent obliquely upward to become an oil passage E5 communicating with the hydraulic passage in the rear rocker arm shaft 165r of the valve operating cam mechanism 160. An oil passage E6 branched obliquely forward from the middle of E5 communicates with a hydraulic passage in the front rocker arm shaft 165f.

The hydraulic passages in the front and rear rocker arm shafts 165f and 165r communicate with the engagement / disengagement mechanism of the rocker arms 164f and 164r so that hydraulic pressure can be applied.
Therefore, when the hydraulic control valve 168 sends pressure oil to the oil passage E2, the hydraulic pressure can be applied to the engagement / disengagement mechanism, and the intake valves 101f and 101r and the exhaust valves 102f and 102r operate at high speed valve timing.

On the other hand, when the hydraulic control valve 168 switches the valve to let the oil flow out to the oil passage F1, the hydraulic pressure does not act on the engagement / disengagement mechanism, and the intake valves 101f and 101r and the exhaust valves 102f and 102r operate at the low speed valve timing.
At this time, as shown in FIG. 5, the oil that has flowed into the oil passage F1 is supplied to the left bearing 62 of the front balancer shaft 60 and passes through the center hole 60a of the front balancer shaft 60 from the right end opening to the crank chamber 22C. Discharged inside.

  The internal combustion engine 20 as described above includes a secondary air supply device 230, and the front and rear cylinder heads 24f, 24r and the rocker arm holders 25f, 25r are combined with the intake valves 101f, 101r, the exhaust valves 102f, 102r, and the rocker arm shaft. When the cylinder head portions 24fa and 24ra that support 150f, 150r, 155f, and 155r are referred to, secondary air supply devices 230 are provided in the front and rear banks respectively in the cylinder head portions 24fa and 24ra and the cylinder head covers 26f and 26r.

  Referring to FIG. 3 which is a top view of the rear cylinder head portion 24ra, there is a combustion chamber 105r at a substantially central portion of the rear cylinder head portion 24ra, and two spark plugs 117r and 117r are inserted into the combustion chamber 105r. The fitting insertion holes 220L and 220R are formed on the left and right.

  An intake port 103r and an exhaust port 104r that open to the combustion chamber 105r extend back and forth, and an intake valve 101r that opens and closes the opening of the intake port 103r and an exhaust valve 102r that opens and closes the opening of the exhaust port 104r are arranged forward and backward. Has been.

  The rocker arm holder 25r has a rectangular cylinder head side valve storage chamber 231h between the front and rear intake valves 101r and the exhaust valve 102r and between the ignition plugs 117r and 117r inserted into the left and right insertion holes 220L and 220R. The rectangular opening periphery opened above the cylinder head side valve storage chamber 231h is cut out, and the rectangular reed valve 232 is fitted in accordance with the cutout.

  A cover side valve storage chamber 231c corresponding to the cylinder head side valve storage chamber 231h is formed on the cylinder head cover 26r covering the cylinder head portion 24ra, and the cylinder head side valve storage chamber 231h and the cover side valve storage chamber 231c are formed. And a reed valve 232 fitted in a notch on the opening periphery of the cylinder head side valve storage chamber 231h is sandwiched between the opening end surfaces of the cover side valve storage chamber 231 of the cylinder head cover 26r. (See FIG. 13).

Therefore, the valve storage chamber 231 is partitioned by the reed valve 232 to define an upper cover side valve storage chamber 231c and a lower cylinder head side valve storage chamber 231h.
That is, the reed valve 232 includes left and right ignition plugs 117r and 117r and front and rear intake valves 101.
r, provided in a valve storage chamber 231 surrounded by an exhaust valve 102r.
The reed valve 232 opens to the cylinder head side valve storage chamber 231h side where the valve body 232a is located below.

  From the cover-side valve storage chamber 231c formed between the intake valve 101r and the exhaust valve 102r in the rocker arm holder 25r, a communication hole 235c is formed obliquely downward from the rear position with reference to FIG. A communication hole 235h extends upward from an upper wall surface of the head 24r near the combustion chamber 105r of the exhaust port 104r and communicates with a communication hole 235c on the rocker arm holder 25r side.

Therefore, the cylinder head side valve storage chamber 231h in which the reed valve 232 is provided communicates with the exhaust port 104r through the communication holes 235c and 235h at a substantially shortest distance.
In addition, the communication hole 235h communicates with the vicinity of the combustion chamber 105r of the exhaust port 104r.

As shown in FIG. 13, a connecting pipe 236 is fitted into a hole formed in the left wall of the cover side valve storage chamber 231c of the cylinder head cover 26r.
The connection pipe 236 protrudes to the outside, and a tube extending from the air cleaner 130 is connected, although not shown.

  The secondary air supply device 230 in the rear bank has the above-described structure, and the secondary air supply device 230 in the front bank has the same structure, and the same reference numerals are used for the same members.

  When the pulsation of the exhaust pressure in the exhaust ports 104f and 104r acts on the reed valve 232 of the valve storage chamber 231 via the communication holes 235c and 235h to operate the valve body 232a and open the valve, the air cleaner 130 opens the cover side valve storage chamber. The secondary air supplied to 231c flows to the cylinder head side valve storage chamber 231h side, and is introduced into the vicinity of the combustion chambers 105f and 105r of the exhaust ports 104f and 104r through the communication holes 235c and 235h.

  The secondary air introduced in the vicinity of the combustion chambers 105f and 105r of the exhaust ports 104f and 104r acts on the high-temperature exhaust gas close to the combustion chambers 105f and 105r of the exhaust ports 104f and 104r, and unburned components in the exhaust gas. It is possible to effectively burn (oxidize) HC and CO to purify the exhaust gas with a high purification rate.

  The reed valve 232 is located above the combustion chambers 105f and 105r and between the intake valves 101f and 101r supported by the cylinder head portions 24fa and 24ra and the exhaust valves 102f and 102r, and the cylinder head portions 24fa and 24ra and the cylinder head covers 26f and 26r. Therefore, the reed valve 232 is arranged using the space between the intake valves 101f and 101r and the exhaust valves 102f and 102r, the outer peripheral portion is not bulged, and the cylinder head The size of the parts 24fa and 24ra and the cylinder head covers 26f and 26r can be avoided.

  As in the internal combustion engine 20, one combustion chamber 105f, 105r is provided with two ignition plugs 117f, 117f, 117r, 117r, and intake valves 101f, 101r, exhaust valves 102f, 102r, and two ignitions. Since the reed valve 232 is disposed in an area surrounded by the plugs 117f, 117f, 117r, and 117r, the large cylinder head portions 24fa and 24ra and the cylinder head covers 26f and 26r are provided even in an internal combustion engine having a plurality of ignition plugs. Can be avoided.

  As shown in FIG. 3, since the reed valve 232 is arranged using a dead space between the intake system rocker arm shaft 150r and the exhaust system rocker arm shaft 155r, the cylinder head portions 24fa and 24ra, the cylinder head cover 26f, 26r can be downsized.

  In the internal combustion engine 20, valve shafts of cam shafts 161f and 161r are arranged on the crankcase 22 side, and cylinder heads 24f and 24r are driven by push rods 150f, 150r, 158f and 158r by rotation of the camshafts 161f and 161r. Since the upper intake valves 101f and 101r and the exhaust valves 102f and 102r are operated, the camshaft is not provided above the cylinder heads 24f and 24r. Therefore, the cylinder head portions 24fa and 24ra and the cylinder head cover 26f are not provided. , 26r can be further reduced in size, and a space for arranging the reed valve 232 is easily secured.

1 is an overall left side view of a motorcycle according to an embodiment of the present invention. It is the left view made into the partial cross section of a V-type internal combustion engine. It is a top view of a rear cylinder head part. It is sectional drawing cut | disconnected by the IV-IV line of FIG. It is sectional drawing cut | disconnected by the VV line | wire of FIG. It is sectional drawing cut | disconnected by the VI-VI line of FIG. It is a partial top view inside V bank. It is explanatory drawing explaining a motion of a rear side connecting rod. It is a perspective view of a front side connecting rod. It is a perspective view of a rear side connecting rod. It is a decomposition | disassembly side view of the back side connecting rod. It is a disassembled sectional view of the same rear side connecting rod. It is sectional drawing of a rear rocker arm holder and a cylinder head cover.

Explanation of symbols

20 ... Internal combustion engine, 21 ... Crankshaft, 22 ... Crankcase, 23f ... Front bank cylinder, 23r ... Rear bank cylinder, 24fa, 24ra ... Cylinder head, 24f, 24r ... Cylinder head, 25f, 25r ... Rocker arm holder, 26f, 26r ... Cylinder head cover,
101f, 101r ... intake valve, 102f, 102r ... exhaust valve, 103f, 103r ... intake port, 104f, 104r ... exhaust port, 105f, 105r ... combustion chamber, 117f, 117r ... ignition plug, 130 ... air cleaner, 150f, 150r ... Intake system rocker arm shaft, 158f, 158r ... Exhaust system push rod, 161f, 161r ... Camshaft,
230 ... Secondary air supply device, 231 ... Valve storage chamber, 232 ... Reed valve, 235h, 235c ... Communication hole, 236 ... Connection pipe.

Claims (2)

A secondary air supply device (230) is provided , and the camshaft (161r) of the valve operating system is arranged on the crankcase (22) side, and the camshaft (161r) is rotated through the push rods (153r, 157r). In the OHV type internal combustion engine in which the intake valve (101r) and the exhaust valve (102r) on the cylinder head (24r) are operated ,
The intake valve (101r) is moved to the intake port (103r) side and the exhaust valve (102r) is moved to the exhaust port (104r) side in a slanting manner with respect to the cylinder axis and obliquely with respect to the cylinder axis. Is arranged to open and close the valve,
An intake rocker arm shaft (150r) and an exhaust rocker arm shaft (155r) are provided in a direction orthogonal to the moving directions of the intake valve (101r) and the exhaust valve (102r),
The intake valve and the exhaust valve are each opened and closed by swinging of an intake rocker arm and an exhaust rocker arm that are respectively supported by an intake rocker arm shaft and an exhaust rocker arm shaft.
The reed valve (232) operated by the pulsation of the exhaust pressure in the secondary air supply device (230) is a cylinder above the combustion chamber (105r) between the intake rocker arm shaft (150r) and the exhaust rocker arm shaft (155r). there between the intake valve (101 r) and the exhaust valve (102r) of the head portion (24Ra) is supported, and the cylinder head portion, a cylinder head cover which is fixed to overlap the upper surface of the cylinder head portion (24Ra) ( 26r), the internal combustion engine reed valve arrangement structure. The internal combustion engine includes a plurality of spark plugs (117r, 117r) that are obliquely inserted into the cylinder head (24r) and face the combustion chamber (105r),
The lead of the internal combustion engine according to claim 1, wherein the reed valve is disposed in a region surrounded by the intake valve (101r), the exhaust valve (102r), and the plurality of spark plugs (117r, 117r). Valve arrangement structure.

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