DE19946981B4 - Internal combustion engine - Google Patents

Abstract

Internal combustion engine, in the intermediate piston, which are slidably inserted in provided in a cylinder block (B _L, B _R) cylinder bores (21 _L, 21 _R), and a cylinder head (24 _L, 24 _R) combustion chambers (26 _L, 26 _R) are formed;
wherein a camshaft (46 _L , 46 _R ) with intake valves (36 _L , 36 _R ) and exhaust valves (37 _L , 37 _R ) for opening / closing of intake ports (34 _L , 34 _R ) and exhaust ports (35 _L , 35 _R is coupled), which are _R) arranged in the cylinder head (24L, 24, to be associated with the combustion chambers (26 _L, 26 _R) in combination; and
wherein a control mechanism (68 _L , 68 _R ) for halving the speed of a crankshaft (29) and for transmitting the reduced speed to the camshaft (46 _L , 46 _R ) between the crankshaft (29) and the camshaft (46 _L , 46 _R ) is provided;
wherein the intake valves (36 _L , 36 _R ) and the exhaust valves (37 _L , 37 _R ) are arranged in parallel at locations extending from a plane (38 _L , 38 _R ) defined by the axial lines of the cylinder bores (21 _L , 21 _R ) and the axis line of the crankshaft (29) passes, to one side ...

Description

The The invention relates to an internal combustion engine operating between pistons, used slidably in provided in a cylinder block cylinder bores and having a cylinder head combustion chambers; being a camshaft with inlet valves and exhaust valves to open / close Inlet channels or Outlet channels coupled is arranged in the cylinder head so that it with communicate with the combustion chambers; and wherein a control mechanism halving the speed of a crankshaft and transmitting the reduced speed on the camshaft between the crankshaft and the camshaft is provided.

A Machine of this type is disclosed, for example, in Japanese Utility Model Laid-Open Publication No. SHO 63-65811. In this machine, the rotational movement a single camshaft by individual rocker arms in a linear motion to open / close intake valves and exhaust valves converted, or the intake valves and exhaust valves are opened / closed by a pair of camshafts, one of which the intake valves and the other associated with the exhaust valves is.

at the conventional one Machine, at the intake valves and the exhaust valves opened / closed by the above mechanisms It is necessary that the Rocker arms or the camshafts individually for the intake valves and the exhaust valves are provided. Here it is difficult to configure a Valve system mechanism for opening / closing the intake valves and the exhaust valves to simplify.

From the DE 36 21 478 A1 is a single-cylinder internal combustion engine according to the preamble of claim 1 is known. There, the cylinder and the valves are vertical.

The DE 195 48 329 C2 shows an internal combustion engine whose valve axes and cylinder axis are parallel.

task The invention is therefore, in a generic internal combustion engine Simplify valve system and below the level sufficient To leave room.

to solution The object is proposed a machine according to claim 1.

There in this configuration, the intake valves and the exhaust valves can be opened / closed directly by the common camshaft, can be the configuration of the valve system mechanism for opening / closing the intake valves and exhaust valves significantly simplify. Since the valves are offset upwards, there is enough space below the level. In the case, that the Machine attached to a motorcycle can accommodate the driver's feet be used, especially if the machine as a boxer engine is trained.

Prefers are on the side, the arrangement side of the intake valves and the exhaust valves with respect to Level is opposite, spark plugs attached to the cylinder head so as to the central portions the combustion chambers have.

hereby let the spark plugs easily arrange such that they to the middle sections of the combustion chambers, without interfering with the intake valves and the exhaust valves disturb.

Preferably open the inlet channels and the Outlet channels to side surfaces of the Cylinder head on both sides of the plane.

hereby let yourself an intake system and an exhaust system easily connect to the cylinder head.

Prefers are from the intake ports and the Outlet ducts those Channels, extending to the side surface of the cylinder head open, the re the plane of the arrangement side of the intake valves and the exhaust valves is opposite, curved on one end side of the camshaft so or they veered out the spark plugs handle, which are mounted in the cylinder head so that they point the combustion chambers.

hereby let the spark plugs easily arrange such that they to the middle sections of the combustion chambers, without interfering with the Inlet channels and to disturb the outlet channels.

Preferably, on the side opposite to the plane of the arrangement side of the intake valves and the exhaust valves, the cylinder head has a plurality of through holes including those respectively disposed at the corresponding portion between the adjacent combustion chambers, the plurality of through holes being spaced at intervals Axialrichtung of the camshaft are arranged such that fastening bolts can be used to attach the cylinder head to the cylinder block; and wherein a distance between a center of that one through hole, which the spark plugs on the one Side of the camshaft adjacent channels, and a center of one of the channel associated combustion chambers is greater than half of a distance between the centers of adjacent these combustion chambers.

If the through holes, through which the fastening bolts for fixing the cylinder head can be used on the cylinder block, are arranged so that they the spark plugs adjacent to the one end side of the camshaft bypassing channels it is necessary that the channels avoiding the through holes bent are. In this case, the through holes can be arranged such that the curvature of the channels becomes low and thus the flow resistance in the channels is lowered.

Prefers has on the assembly side of the intake valves and the exhaust valves in terms of the plane of the cylinder head has a plurality of through holes, including those each disposed between adjacent combustion chambers, wherein the plurality of through holes arranged in the axial direction of the camshaft with such distances are that fixing bolts used to attach the cylinder head to the cylinder block can be; and wherein a distance between the center of the one outermost End on the one end side of the camshaft arranged through hole and the middle of the one at the extreme End of one end side of the camshaft arranged combustion chamber less than half a distance between the centers of adjacent combustion chambers.

hereby Is it possible, the one end portion of the cylinder head on one end side of the camshaft as close as possible to bring to the center of the cylinder bore, which is at the extreme End of the one end side of the camshaft is located, i. at the bend side the spark plugs immediate channels, so that one the length of the Cylinder head in the axial direction of the camshaft can run as short as possible.

Prefers is a valve system chamber between the cylinder head and a Head cover designed so that they are from the plane to accommodated above offset camshaft; one end of a control chamber for receiving the control mechanism with the valve system chamber in Connection stands, with an endless chain of the control mechanism to one at one end of the crankshaft fixed drive pinion and a driven pinion fixed to one end of the camshaft is laid around; and wherein the lower portion of the other end of the Control chamber with the crankcase communicates.

There in this version the control mechanism transmits the force by means of the chain can the oil flow into the control chamber containing the control mechanism; and because the camshaft over the crankshaft is arranged, the oil in the valve system chamber towards the crankshaft at a lower level in the control chamber flow, with the result that the oil in the Valve system chamber easily return to the crankcase side can. Furthermore, the spark plugs on the side, concerning the Plane of the arrangement side of the intake valves and the exhaust valves is opposite to the lower portion of the cylinder head are arranged, can be Dissipate water easily, that on the outside surface side the cylinder head in the vicinity the spark plugs has penetrated.

Prefers For example, the engine is mounted such that a plurality of the cylinder bores are parallel are arranged, wherein a pair of cylinder bore rows on both sides the crankshaft opposite each other is arranged; wherein a plurality of the intake valves and a plurality the exhaust valves are arranged in parallel so that they from the plane of each of Cylinder bore rows are offset upwards; and the one End of the crankshaft in the axial direction at the front of the motorcycle is arranged.

There in this version the camshaft over the axis line of each cylinder bore row is arranged and the the spark plugs immediate channels curved forward are, get You can easily leave room for the driver to get his feet in one lower rear section of the motorcycle mounted on the motorcycle with horizontally opposite Cylinders can extend forward.

following Be exemplary embodiments of Invention with reference to the attached Drawings described. Show it:

1 a side view of a mounted on a motorcycle engine with horizontally opposed cylinders;

2 a front view along arrow 2 of 1 ;

3 an enlarged sectional view taken along line 3-3 of 1 ;

4 a sectional view taken along line 4-4 of 3 ;

5 an enlarged view along line 5-5 of 4 ;

6 an enlarged view along line 6-6 of 4 ;

7 an enlarged sectional view taken along line 7-7 of 4 ;

8th an enlarged view along line 8-8 of 4 ;

9 an enlarged sectional view taken along line 9-9 of 4 ;

10 a sectional view taken along line 10-10 of 8th ;

11 a sectional view taken along line 11-11 of 3 ;

12 a sectional view taken along line 12-12 of 11 ;

13 a schematic view of the back of a transmission housing; and

14 an enlarged sectional view taken along line 14-14 of 13 ,

To the 1 and 2 , On a motorcycle horizontally lying a four-stroke multi-cylinder engine (eg six-cylinder) with opposing cylinders, here in boxer design, attached. An engine main body E of the engine comprises a left engine block B _L located with respect to the direction of travel of the motorcycle on the left side of the motorcycle and a right engine block B _R with respect to the direction of travel of the motorcycle on the right side of the motorcycle is arranged.

To the 3 and 4 , The left engine block B _L includes a left cylinder block 23 _l and a left cylinder head 24 _l that with the left cylinder block 23 _l connected is. The left cylinder block 23 _l has a left cylinder bore row 22 _l with a plurality (eg three) cylinder bores 21 _l which are arranged in parallel. The left cylinder head 24 _l contains combustion chambers 26 _l , each between an associated one of the cylinder bores 21 _l and a piston 25 _l is formed, which is displaceable in the cylinder bore 21 _l is used. A left crankcase 27 _l is integral with the left cylinder head 24 _l opposite side of the cylinder block 23 _l educated. The right engine block B _R includes a right cylinder block 23 _r and a right cylinder head 24 _R that with the right cylinder block 23 _r connected is. The right cylinder block 23 _r has a right cylinder bore row 22 _R with a plurality (eg three) cylinder bores 21 _r which are arranged in parallel. The right cylinder head 24 _R contains combustion chambers 26 _R , each between the associated cylinder bores 21 _r and a piston 25 _R are formed, which is displaceable in the cylinder bore 21 _r is used. A right crankcase 27 _R is integral with the right cylinder head 24 _R opposite side of the cylinder block 23 _r educated.

The left and right machine blocks B _L and B _R are opposite to each other, wherein the axial lines of the cylinder bores 21 _l and 21 _r extend substantially in the horizontal direction. The left crankcase 27 _l of the left engine block B _L is on the right crankcase 27 _R of the right engine block B _R fixed such that they between them a crank chamber 28 form.

The pistons 25 _l and 25 _R in the left and right machine blocks B _L and B _R are common about respective connecting rods 30 _l and 30 _R with a crankshaft 29 connected. The crankshaft 29 is arranged so that it is one end to the front of the motorcycle in the longitudinal direction of the motorcycle and extends its axial line in the longitudinal direction of the motorcycle. The crankshaft 9 is on the left and right crankcases 27 _l and 27 _R (in this embodiment the left crankcase 27 _l ) stored. In particular, the crankcase 29 through storage walls 31 rotatably held integral with the left crankcase 27 _l are formed in several places, which are arranged at a distance in the axial longitudinal direction of the crankshaft, and bearing caps 32 , each by means of a bolt pair 33 at an associated one of the bearing walls 31 are attached.

Each of the cylinder bores 21 _r that the cylinder bore series 22 _R form part of the right engine block B _R , is in the longitudinal direction of the motorcycle of an associated one of the opposite cylinder bores 21 _l that the cylinder bore series 22 _l from the left engine block B _L to offset a first offset amount L1 forward.

To the 5 . 6 and 7 , The left cylinder head 24 _l contains a pair of inlet channels 34 _l and outlet channels 35 _l that with the combustion chambers 26 _l are connected, each pair one of the combustion chambers 26 _l assigned. The left cylinder head 24 _l also includes intake valves 36 _l for opening / closing the associated inlet channels 34 _l and exhaust valves 37 _l for opening / closing the associated outlet channels 35 _l ,

The intake valves 36 _l and the exhaust valves 37 _l extending in the direction parallel or orthogonal to the axial line of the crankshaft 29 extend are from a plane 38 _l passing through the axial lines of the cylinder bores 21 _l and the axial line of the crankshaft 29 passes, offset upwards, the exhaust valves 37 _l in the longitudinal direction of the motorcycle in front of the intake valves 36 _l lie. The left cylinder head 24 _l also contains spark plugs 39 _l , respectively to the central portion of the associated combustion chambers 26 _l at a point that extends between the associated pair of intake valves 36 _l and exhaust valves 37 _l at the arrangement side of the intake valves 36 _l and exhaust valves 37 _l regarding the plane 38 _l located opposite side, ie below the level 38 _l ,

The respective intake valves 36 _l and exhaust valves 37 _l are on the left cylinder head 24 _l mounted so that they are at an acute angle with respect to the plane 38 _l are inclined. On the side, the arrangement side of the intake valves 36 _l and the exhaust valves 37 _l regarding the plane 38 _l opposite, ie below the level 38 _l , contains the left cylinder head 24 _l Candles mounting holes 40 _l for attaching the spark plugs 39 _l such that the spark plugs 39 _l at an acute angle with respect to the plane 38 _l are inclined. That is, the spark plugs 39 _l are on the left cylinder head 24 _l mounted so that they are in relation to the plane 38 _l are inclined downwards.

In the projection plane, the axial lines of the cylinder bores 21 _l intersects at right angles, are the inlet channels 34 _l in the left cylinder head 24 _l provided so that it is the plane 38 _l cut substantially at right angles, and they open to a side surface of the left cylinder head 24 _l on the side of the inlet valves 36 _l and the exhaust valves 37 _l in terms of the level 38 _l ie above the level 38 _l , The outlet channels 35 _l open to the other side surface of the cylinder head 24 _l on the opposite side of the arrangement side of the intake valves 36 _l and the exhaust valves 37 _l in terms of the level 38 _l ie below the level 38 _l , In particular, the outlet channels 35 _l to one end side of the crankshaft 29 _l or to the front of the motorcycle bulbous curved to the spark plugs 39 _l to get around, ie the candle mounting holes 40 _l for attaching the spark plugs 39 _l ,

The respective outlet channels 35 _l are formed so as to be inclined downwardly toward the central portion of the motorcycle in the width direction, and to open toward the other side surface, that is, to the lower side of the left cylinder head 24 _l , An exhaust system 43 _l includes exhaust pipes 41 _l , respectively with the associated one of the outlet channels 35 _l connected, a catalyst 42 , a muffler (not shown) and the like. The respective exhaust pipes 41 _l the exhaust system 43 _l are inclined so that they approach each other in the width direction of the motorcycle to the central portion toward each other, as they are under the cylinder head 24 _l are separated from each other, and their one opening is connected to the outer end of the associated outlet channels 35 _l connected.

The center of the opening at the outer end of the respective outlet channel 35 _l is in the longitudinal direction of the motorcycle from a center C _{L of} the associated combustion chamber 26 _l offset by a second offset amount L2 forward.

A single camshaft 46 _l parallel to the crankshaft 29 runs and whose axial line orthogonal to the axial lines, ie the opening / closing working axes of the intake valves 36 _l and the exhaust valves 37 _l runs is on the arrangement side of the intake valves 36 _l and the exhaust valves 37 _l in terms of the level 38 _l arranged, ie above the level 38 _l , On the other hand, the upper ends of the intake valves 36 _l and the exhaust valves 37 _l , which are biased by springs in the valve closing direction, with valve tappets 47 _l in contact with the cylinder head 37 _l in the Össnungs / closing axes of the valves 36 _l and 37 _l are slidably mounted. The camshaft 46 _l has inlet side cams 48 _l that with the intake valves 36 _l associated valve tappets 47 _l in contact, as well as outlet side cams 49 _l that with the exhaust valves 37 _l associated valve tappets 47 _l are in contact. In other words, the intake valves 36 _l and the exhaust valves 37 _l be through the inlet side cam 48 _l and the exhaust side cams 49 _l the camshaft 46 _l each directly opened and closed.

Several (eg four) axially spaced portions of the camshaft 46 _l are rotatable by cam bearing sections 50 _l stored on the left cylinder head 24 _l are provided, as well as by a cam holder 51 _l , in common with the cam bearing sections 50 _l connected is. From the four cam bearing sections 50 _l There are three each on the left cylinder head 24 _l provided such that it between the pair of intake valves 36 _l and the exhaust valves 37 _l for every combustion chamber 26 _l are arranged, and the remaining is on the left cylinder head 24 _l provided so that it is outside the combustion chamber 26 _l located at the extreme end of the one end side of the camshaft 46 _l is arranged (front of the motorcycle).

An oil channel 52 _l , whose both ends are closed, is coaxial in the camshaft 46 _l intended. As in 3 shown, owns the camshaft 46 _l oil holes 53 _l in places that the cam bearing sections 50 _l correspond. The oil holes 53 _l extend from the inside to the outside of the camshaft 46 _l , As a result, lubricating oil from the inside of the camshaft 46 _l the cam bearing sections 50 _l and the cam holder 51 _l fed. Furthermore, an oil groove 54 _l leading to the outside of the camshaft 46 _l points, in the cam bearing portion 50 _l at the extreme end of the one end side of the camshaft 46 _l arranged, and one in the left cylinder head 24 _l and the left cylinder block 23 _l provided oil channel 55 _l stands with the oil groove 54 _l in connection. As a result, oil from the oil passage 55 _l in the oil channel 52 _l in the camshaft 46 _l through the oil groove 54 _l and the oil hole 53 _l fed.

Each of the intake-side cams 48 _l and the exhaust side cam 49 _l has an oil hole, not shown, with the oil channel 52 _l in the notch shaft 46 _l communicates. The outer end of the oil hole opens to the outer surface of the associated intake-side cam 48 _l and outlet side cam 49 _l , As a result, lubricating oil also becomes the sliding contact portion between the respective intake side cams 48 _l and the exhaust side cam 49 _l and the valve lifters 47 _l supplied to the respective intake valves 36 _l and the exhaust valves 37 _l are provided.

The left cylinder head 24 _l is in several places on the left cylinder block 23 _l attached. On the side, the arrangement side of the intake valves 36 _l and the exhaust valves 37 _l in terms of the level 38 _l opposite, ie below the level 38 _l , The left cylinder head has at a distance in the axial direction of the camshaft 46 _l several (eg four) through holes 56 _l , Of the four through holes 56 _l are each two between the adjacent combustion chambers 26 _l arranged. mounting bolts 57 _l for fixing the cylinder head 24 _l on the left cylinder block 23 _l are in the through holes 56 _l used.

Every through hole 56 _l is on one end side (the left side in 7 ) of the camshaft 46 _l an associated exhaust duct 35 _l adjacent, bypassing the spark plugs 39 _l the combustion chambers 26 _l , Such a through hole 56 _l has such a position that a longitudinal distance L4 between a center of the through hole 56 _l and a center C _{L of} the associated combustion chamber 26 _l is greater than a value L3 (L3 <L4). The value L3 denotes half of a distance (2L3) between the centers C _{L of} adjacent combustion chambers 26 _l ,

On the side of the inlet valves 36 _l and the exhaust valves 37 _l in terms of the level 38 _l ie above the level 38 _l , owns the left cylinder head 24 _l at a distance in the axial direction of the camshaft 46 _l several (eg four) through holes 58 _l , Of the four through holes 58 _l are two combustion chambers between each other 26 _l arranged. mounting bolts 59 _l for securing the left cylinder head 24 _l on the left cylinder block 23 _l are in the through holes 58 _l used. Every through hole 58 _l ie each fixing bolt 59 _l is attached to a position where it is partly from the camshaft 46 _l is covered.

A left head cover 60 _l is on the left cylinder head 24 _l mounted such that a valve system chamber 61 _l for receiving the camshaft 46 _l and the cam holder 51 _l between the left head cover 60 _l and the left cylinder head 24 _l is trained. Because the camshaft 46 _l above the level 38 _l is arranged, which the axial lines of the cylinder bores 21 _l , contains, is the valve system chamber 61 _l also between the left head cover 60 _l and the left cylinder head 24 _l designed so that they from the plane 38 _l is offset upwards.

A lid section 62 _l is integral with the left head cover 60 _l educated. Sections connected to the outlet channels 35 _l the exhaust pipes 41 _l the exhaust system 43 _l are connected, and the underlying spark plugs 39 _l are with the lid section 62 _l covered from the outside.

To the 8th and 9 , The right cylinder head 24 _R contains a pair of inlet channels 34 _R and outlet channels 35 _R that with the combustion chambers 26 _R are connected, each pair of a combustion chamber 26 _R assigned. The right cylinder head 24 _R also includes intake valves 36 _R for opening / closing the associated inlet channels 34 _R and exhaust valves 37 _R for opening / closing the associated outlet channels 35 _R ,

The intake valves 36 _R and the exhaust valves 37 _R extending in the direction parallel or orthogonal to the axial line of the crankshaft 29 extend are from a plane 38 _R passing through the axial lines of the cylinder bores 21 _r and the axial line of the crankshaft 29 passes, offset upwards, the exhaust valves 37 _R in the longitudinal direction of the motorcycle in front of the intake valves 36 _R lie. spark 39 _R , respectively to the central portion of the associated combustion chambers 26 _R are on the right cylinder head 24 _R below the level 38 _R appropriate.

The respective intake valves 36 _R and exhaust valves 37 _R are on the right cylinder head 24 _R at an acute angle with respect to the plane 38 _R inclined. Under the plane 38 _R contains the right cylinder head 24 _R Candles mounting holes 40 _R for attaching the spark plugs 39 _R such that the spark plugs 39 _R at an acute angle with respect to the plane 38 _R are inclined. The spark plugs 39 _R are thus on the right cylinder head 24 _R mounted so that they are in relation to the plane 38 _R are inclined downwards.

In a projection plane, the axial lines of the cylinder bores 21 _r intersects at right angles, are the inlet channels 34 _R in the right cylinder head 24 _R provided so that it is the plane 38 _R cut substantially at right angles, and they open above the plane 38 _R , The outlet channels 35 _R open to the other side surface of the cylinder head 24 _R below the level 38 _R , In particular, the outlet channels 35 _R to one end side of the crankshaft 29 _R or to the front of the motorcycle bulbous curved to the spark plugs 39 _R to get around, ie the candle mounting holes 40 _R ,

The respective outlet channels 35 _R are formed so as to be inclined downwardly toward the central portion of the motorcycle in the width direction, and to be at the lower side of the right cylinder head 24 _R open. An exhaust system 43 _R includes exhaust pipes 41 _r , respectively with the associated one of the outlet channels 35 _R connected, a catalyst 42 , a muffler (not shown) and the like. The respective exhaust pipes 41 _r the exhaust system 43 _R are inclined so that they approach each other in the width direction of the motorcycle to the central portion toward each other, as they are under the cylinder head 24 _R are separated from each other, and their one opening is connected to the outer end of the associated outlet channels 35 _R connected.

The center of the opening at the outer end of the respective outlet channel 35 _R is in the longitudinal direction of the motorcycle from a center C _{R of} the associated combustion chamber 26 _R offset by the second offset amount L2 forward.

The upper ends of the intake valves 36 _R and the exhaust valves 37 _R , which are biased by springs in the valve closing direction, are available with valve tappets 47 _R in contact, on the right cylinder head 24 _R are stored. Inlet side cams 48 _R that with the intake valves 36 _R associated valve tappets 47 _R in contact, as well as outlet side cams 49 _R that with the exhaust valves 37 _R associated valve tappets 47 _R are in contact with each other on a single camshaft 46 _R arranged above the level 38 _R lies. The camshaft 46 _R is parallel to the crankshaft 29 and the axial line thereof is orthogonal to the opening / closing axes of the intake valves 36 _R and the exhaust valves 37 _R , In other words, the intake valves 36 _R and the exhaust valves 37 _R be through the inlet side cam 48 _R and the exhaust side cams 49 _R the camshaft 46 _R each directly opened and closed.

Several (eg four) axially spaced portions of the camshaft 46 _R are rotatable on cam bearing sections 50 _R stored on the right cylinder head 24 _R are provided, as well as by a cam holder 51 _R , in common with the cam bearing sections 50 _R connected is. From the four cam bearing sections 50 _R There are three each on the right cylinder head 24 _R provided such that it between the pair of intake valves 36 _R and the exhaust valves 37 _R for every combustion chamber 26 _R are arranged, and the remaining is on the right cylinder head 24 _R provided so that it is outside the combustion chamber 26 _R located at the extreme end of the one end side of the camshaft 46 _R is arranged (front of the motorcycle).

As in 3 shown, owns the camshaft 46 _R oil holes 53 _R in places that the cam bearing sections 50 _R correspond. The oil holes 53 _R extend from the inside to the outside of the camshaft 46 _R , As a result, lubricating oil from one in the camshaft 46 _R trained oil channel 52 _R , the cam bearing sections 50 _R and the cam holder 51 _R through the oil holes 53 _R fed. Furthermore, an oil groove 54 _R leading to the outside of the camshaft 46 _R points, in the second cam bearing portion 50 _R at the extreme end of the one end side of the camshaft 46 _R arranged, and one in the right cylinder head 24 _R and the right cylinder block 23 _r provided oil channel 55 _R stands with the oil groove 54 _R in connection.

Each of the intake-side cams 48 _R and the exhaust side cam 49 _R has an oil hole, not shown, with the oil channel 52 _R in the camshaft 46 _R communicates. As a result, lubricating oil also becomes the sliding contact portion between the respective intake side cams 48a and the exhaust side cam 49 _R and the associated valve tappets 47 _R supplied to the respective intake valves 36 _R and the exhaust valves 37 _R are provided.

Under the plane 38 _R has the right cylinder head at a distance in the axial direction of the camshaft 46 _R several (eg four) through holes 56 _R , Of the four through holes 56 _R each are two between the adjacent ones of the combustion chambers 26 _R arranged. mounting bolts 57 _R for fixing the cylinder head 24 _R on the right cylinder block 23 _r are in the through holes 56 _R used.

Every through hole 56 _R is on one end side (the right side in 9 ) of the camshaft 46 _R an associated exhaust duct 35 _R adjacent, bypassing the spark plugs 39 _R the combustion chambers 26 _R , Such a through hole 56 _R has such a position that a longitudinal distance L4 between a center of the through hole 56 _R and a center C _{R of} the associated combustion chamber 26 _R is greater than a value L3 (L3 <L4). The value L3 denotes half of a distance between the centers C _{R of} adjacent combustion chambers 26 _R ,

Above the level 38 _R owns the right cylinder head 24 _R at a distance in the axial direction of the camshaft 46 _R several (eg four) through holes 58 _R , Of the four through holes 58 _R are two combustion chambers between each other 26 _R arranged. mounting bolts 59 _R for fixing the right cylinder head 24 _R on the right cylinder block 23 _r are in the through holes 58 _R turned puts. Every through hole 58 _R ie each fixing bolt 59 _R is attached to a position where it is partly from the camshaft 46 _R is covered.

Now especially for 10 , Of the several (eg four) through holes 58 _R this is at the extreme end of one end side of the camshaft 46 _R arranged through hole 58 _R in the cam bearing portion 50 _R the four cam bearing sections 50 _R provided at the outermost end on one end side of the camshaft 46 _R located. The oil groove 54 _R is in the cam bearing portion 50 _R adjacent the above-described cam bearing portion 50 _R provided at the outermost end on one end side of the camshaft 46 _R located.

Further, a distance L5 is between a center of the through hole 58 _R located at the extreme end on one end side of the camshaft 46 _R located, and the center C _{R of} the combustion chamber 26 _R located at the extreme end on one end side of the camshaft 46 _R is less than the value L3 (L5 <L3). The value L3 denotes, as described above, half the distance between the centers C _{R of} adjacent ones of the combustion chambers 27 _R ,

A right head cover 60 _R is on the right cylinder head 24 _R mounted such that a valve system chamber 61 _r for receiving the camshaft 46 _R and the cam holder 51 _R between the right head cover 60 _R and the right cylinder head 24 _R is trained. The valve system chamber 61 _r is between the right head cover 60 _R and the right cylinder head 24 _R designed so that they from the plane 38 _R is offset upwards.

A lid section 62 _R is integral with the right head cover 60 _R educated. Sections connected to the outlet channels 35 _R the exhaust pipes 41 _r the exhaust system 43 _R are connected, and the underlying spark plugs 39 _R are with the lid section 62 _R covered from the outside.

Regarding the inlet channels 34 _l and the outlet channels 35 _l in the left cylinder head 24 _l are provided, and the intake ports 34 _R and the outlet channels 35 _R provided in the right cylinder head, as described above, is the relative positional relationship between the intake ports 34 _l and the outlet channels 35 _l along the axial line of the crankshaft 29 _l in the left cylinder head 34 _l almost equal to that of the relative positional relationship between the intake ports 34 _R and the outlet channels 35 _R along the axial line of the crankshaft 29 _R in the right cylinder head 24 _R designed.

A throttle body 63 , an intake manifold 64 and an intake system 66 including fuel injectors 65 for each of the combustion chambers 26 _l and 26 _R are provided, are above a point between the two cylinder heads 24 _l and 24 _R arranged. The inlet manifold 64 is with the inlet channels 34 _l and 34 _R both cylinder heads 24 _l and 24 _R connected.

Secondary air supply channels 44 _l , each with the outlet channels 35 _l are connected in the cylinder head 24 _l and the cylinder block 23 _l of the left engine block B _L , and secondary air supply passages 44 _R , each with the outlet channels 35 _R are connected in the cylinder head 24 _R and the cylinder block 23 _r the right machine block B _R provided. These secondary air supply channels 44 _l are equipped with control valves (not shown) via check valves 45 connected in the cylinder block 23 _l are provided, and the secondary air supply channels 44 _R are similarly equipped with control valves (not shown) via check valves 45 connected in the cylinder block 23 _r are provided.

Now especially 11 which requires a control mechanism 68 _l between an end portion of the camshaft 46 _l from the left engine block B _L and an end portion of the crankshaft 29 is provided. The control mechanism 68 _l Halves the speed of the crankshaft 29 and transmitting the reduced speed to the camshaft 36 _l , Further, a control mechanism 68 _R between an end portion of the camshaft 46 _R from the right engine block B _R and an end portion of the crankshaft 29 intended. The control mechanism 68 _R Halves the speed of the crankshaft 29 and transmitting the reduced speed to the camshaft 46 _R ,

The control mechanism 68 _l (or 68 _R ) is configured so that an endless chain 71 _l (or 71 _R ) about a drive pinion 69 _l (or 69 _R ), which at an end portion of the crankshaft 29 is attached, and an output pinion 70 _l (or 70 _R ), which at an end portion of the camshaft 46 _l (or 46 _R ) is attached, lying around. As described above, each of the cylinder bores is 21 _r , the cylinder bore series 22 _R from the right engine block B _R , in the longitudinal direction of the motorcycle from the respective cylinder bores 21 _l , the cylinder bore series 22 _l from the right engine block B _L , offset by the first offset amount L1 forward, and accordingly, the control mechanism 68 _R from the right engine block B _R in the longitudinal direction of the motorcycle from the control mechanism 68 _l offset from the left machine block B _L forward. In this case, a gap L6 is between both control mechanisms 68 _l and 68 _R made smaller than the first offset amount L1 (L6 <L1).

A control chamber 72 _l for receiving the control mechanism 68 _l is formed in the front end portion of the left engine block B _L along the longitudinal direction of the motorcycle so as to extend from the head cover 60 _l over the cylinder head 24 _l and the cylinder block 23 _l to the crankcase 27 _l extends. In particular, one end of the control chamber 72 _l to the valve system chamber 61 _l and its other end points to the crankshaft 29 , Similar is a control chamber 72 _R for receiving the control mechanism 68 _R formed at the front end portion of the right engine block B _R along the longitudinal direction of the motorcycle so as to extend from the head cover 60 _R over the cylinder head 24 _R and the cylinder block 23 _r to the crankcase 27 _R extends. In particular, one end of the control chamber 72 _R to the valve system chamber 61 _r and its other end points to one end of the crankshaft 29 , As a result, the other end portions of both control chambers 72 _l and 72 _R together formed so that they to an end of the crankshaft 29 point. An opening 73 leading to the other end sections of both control chambers 72 _l and 72 _R points is in the left and right crankcases 27 _l and 27 _R provided and is with a cover element 74 covered on the left and right crankcases 27 _l and 27 _R is attached.

In a room at the other end of the control chambers 72 _l and 72 _R is a pulser rotor 75 at an end portion of the crankcase 29 outside both pinions 68 _l and 68 _R attached. An outer circumference of the pulser rotor 75 opposite sensor 76 is on one of the left and right crankcases 27 _l and 27 _R attached (in this embodiment, the left crankcase 27 _l ). The sensor 76 serves to detect the passage of teeth on the outer circumference of the pulser rotor 75 are provided. In this way, the rotational position of the crankshaft 29 through the sensor 76 detected.

A pulser rotor 77 is at an end portion of one of the camshafts 46 _l and 46 _R attached (in this embodiment camshaft 46 _l ) at a location outside of the output pinion 70 _l , A sensor (not shown) for detecting the rotational position of the camshaft 46 _l is on the left cylinder head 24 _l mounted so as to the outer periphery of the pulser rotor 77 faces.

The crankshaft 29 turns in a direction that is in 11 with the arrow 78 is designated. On the left-side control mechanism 68 _l is a chain tensioner 79 _l elastically displaceable with the camshaft 46 _l current section in contact, ie the running below section of the chain 71 _l that from the drive pinion 79 _l to the output pinion 70 _l runs counterclockwise, and a chain guide 80 _l is slidably in contact with the returning portion, that is, the top-running portion of the chain 71 _l that of the output pinion 70 _l to the drive pinion 69 _l runs counterclockwise.

The chain tensioner 79 _l is along the direction of the chain 71 _l educated. An end section of the chain tensioner 79 _l is at the camp cap 32 rotatably mounted, among the plurality of bearing caps 32 for rotatably supporting the crankshaft 29 along with the several storage walls 31 , the control mechanism 68 _l is closest, via a bearing shaft 81 _l whose axis is parallel to the axis of rotation of the crankshaft 29 runs. A clamping ram 82 _l provided with a longitudinal center portion of the chain tensioner 79 _l is in contact and the chain tensioner 79 _l on the chain 71 _l presses, is on the left cylinder block 23 _l appropriate.

The chain guide 80 _l runs along the direction of the chain 71 _l , An end portion of the chain guide 80 _l is about a bolt 83 _l at the control mechanism 68 _l next storage wall 31 stored; and a center portion and the other end portion of the chain guide 80 _l stand with the left cylinder block 23 _l or the left cylinder head 24 _l in contact and are stored at it.

On the right-side control mechanism 68 _R is a chain tensioner 79 _R elastically displaceable with the camshaft 46 _R current section in contact, ie the top section of the chain 71 _R that from the drive pinion 79 _R to the output pinion 70 _R runs counterclockwise, and a chain guide 80 _r is slidably in contact with the returning section, ie the section of the chain running down 71 _R that of the output pinion 70 _R to the drive pinion 69 _R runs counterclockwise.

The chain tensioner 79 _R is along the direction of the chain 71 _R educated. An end section of the chain tensioner 79 _R is at the camp cap 32 rotatably mounted, under the plurality of bearing caps 32 for rotatably supporting the crankshaft 29 along with the several storage walls 31 , the control mechanism 68 _R closest to each other via a bearing shaft 81 _R whose axis is parallel to the axis of rotation of the crankshaft 29 runs. A clamping ram 82 _R provided with a longitudinal center portion of the chain tensioner 79 _R is in contact and the chain tensioner 79 _R on the chain 71 _R presses is on the right cylinder block 23 _r appropriate.

The chain guide 80 _r runs along the direction of the chain 71 _R , An end portion of the chain guide 80 _r is about a bolt 83 _R at one with the right crankcase 27 _R integral bearing section 84 stored; and a center portion and the other end portion of the chain guide 80 _r stand with the right cylinder block 23 _r or the right cylinder head 24 _R in contact and are stored at it.

An end portion of the control chamber 72 _l (or 72 _R ) for receiving the control mechanism 68 _l (or 68 _R ) communicates with the valve system chamber 61 _l (or 61 _r ), and the valve system chamber 61 _l (or 61 _r ) is above the level 68 _l (or 68 _R ), which are the axis of the crankshaft 29 _l and the axes of the cylinder bores 21 _l (or 21 _r ) contains. As a result, oil can escape from the interior of the valve system chamber 61 _l (or 61 _r ) in one end of the control chamber 72 _l (or 72 _R ) is directed to the other end portion of the control chamber 72 _l (or 72 _R ) are introduced, leading to the one end of the crankshaft 29 has. A return hole 85 for connecting the bottoms of both end portions of both control chambers 72 _l and 72 _R with the crank chamber 28 is in the left and right crankcases 27 _l and 28 _R intended.

Now especially 12 , Several ribs 88 for contact with and connection to the multiple bearing walls 31 , which is integral with the left crankcase 27 _l are formed, are integral with the right crankcase 27 _R designed so that they the bearing caps 32 surround. The return hole 85 is formed in an area different from that of the storage wall 31 under the several storage walls 31 leading to both control chambers 72 _l and 72 _R points to the rib 88 in contact and connection with the above bearing wall 31 extends. In particular, the return hole is 85 composed of a depression 86 that in the above storage wall 31 is provided so that it extends over the rib 88 opens, as well as a recess 87 that over the rib 88 is provided so that it extends over the bearing wall 31 opens.

The camp cap 32 is, as described above, on the storage wall 31 with the bolt pair 33 attached and the return hole 85 is along the mounting direction of the bearing cap 32 with the storage wall 31 formed, ie along the axial direction of the bolt 33 ,

The return hole 85 is between the crankcases 27 _l and 27 _R designed so that it is to the side of the left crankcase 27 _l is offset. In particular, of the return hole 85 forming depressions 86 and 87 the depression 86 in the warehouse wall 31 along the axial direction of the bolts 33 formed while the recess 87 in the rib 88 is trained.

A gearbox 90 follows the left and right machine blocks B _L and B _{R in} such a way that they are separated from the crankcases 27 _l and 27 _R extends downwardly and further in the longitudinal direction of the motorcycle from the cylinder blocks 23 _l and 23 _r extends to the rear. As with the return hole described above 85 is a passage hole 89 provided so that it is from the bottom of the bearing wall 31 between the return hole 85 and the interior of the transmission housing 90 is arranged, to the bottom of the rib 88 in contact and connection with the storage wall 31 extends. As a result, oil coming from the control chambers 72 _l and 72 _R through the return hole 85 in the crank chamber 28 has returned, through the passage hole 89 in the gearbox 90 introduced.

As described above, the oil in the valve system chamber 61 _l and 61 _r to the crank chamber 28 through the control chambers 72 _l and 72 _R on the one end sides of the camshafts 64 _l and 64 _R returned. Here are the camshafts 64 _l and 64 _R are arranged substantially in the horizontal direction, it may be desirable, the oil from the other end sides of the camshaft 64 _l and 64 _R to the crank chamber 28 in the valve system chambers 61 _l and 61 _r to return. For this purpose, a return line 91 _l (or 91 _R ), one end of which is connected to the interior of the valve system chamber 61 _l (or 61 _r ) on the other end side of the camshaft 64 _l (or 64 _R ) and the other end to the crank chamber 28 connected in the left cylinder head 24 _l (or the right cylinder head 24 _R ) and the left cylinder block 23 _l (or the right cylinder block 23 _r ) intended.

Now especially to the 13 and 14 , A water pump 94 with a pump shaft 95 that directly with the crankcase 29 is connected to the rear of the gearbox 90 arranged. A housing 96 the water pump 94 is from a pump body 97 for rotatably supporting the pump shaft 95 and a pump cover 98 assembled on the pump body 97 is fixed so that it one on the pump shaft 95 secure impeller 99 covers.

The pump body 97 is integral with the transmission housing 90 educated. The pump cover 98 is on the pump body 97 attached, with a pump chamber 100 between the pump cover 98 and the pump body 97 is trained. The pump shaft 95 is on the pump body 97 rotatably mounted so that its one end in the pump chamber 100 protrudes. An engagement plate 95 for engagement with an engagement recess 29a at the other end of the crankshaft 29 is provided, is at the other end of the pump shaft 95 in front. That is, the one end side of the crankshaft 29 is with the camshafts 64 _l and 64 _R about the control mechanisms 68 _l and 68 _R connected while the other end side of the crankshaft 29 directly with the pump shaft 95 the water pump 94 connected is.

The impeller 99 is in the pump chamber 100 arranged and is at one end of the pump shaft 95 attached. Above the impeller 99 is a recording section 101 connected to the middle section of the pump chamber 100 communicates in the upper section of the pump cover 98 educated.

A wax thermostat 102 , in addition to the water pump 94 is provided is in the receiving portion 101 received so that it is between the pump body 97 and the pump cover 98 is held.

The thermostat 102 is known in the art and includes a support plate 103 between the pump body 97 and the pump cover 98 is held, a thermostatic valve 104 and a bypass valve 105 ,

A first suction opening 106 extending to one end of the receiving section 101 opens is in the upper section of the pump body 97 provided so that they pass through the thermostatic valve 104 can be opened and closed, and a second suction port 107 extending to the other end of the receiving section 101 opens, is in the pump cover 98 provided so that it passes through the bypass valve 105 can be opened and closed. An outlet opening 108 for discharging cooling water in response to the rotation of the impeller 99 is in the pump cover 98 intended. The outlet opening 108 stands with the pump chamber 100 in connection.

A water jacket 109 _l (or 109 _R ) is on the left cylinder block 23 _l (or the right cylinder block 23 _r ), and a water jacket 110 _l (or 110 _r ), with the water jacket 109 (or 109 _R ) is connected to the cylinder block 23 _l (or 23 _r ) intended. The outlet opening 108 the water pump 94 stands with the water-coats 109 _l and 109 _R over cooling water supply pipes 111 in conjunction with the left and right cylinder block 23 _l and 23 _r are connected.

A cooling water outlet pipe 112 _l (or 112 _R ) for discharging cooling water from the water jackets 110 _l (or 110 _r ) is with the left cylinder head 24 _l (or the right cylinder head 24 _R ) connected. The cooling water outlet pipes 112 _l and 112 _R are with the second suction opening 107 the water pump 94 connected, and are also with the inlets of the respective radiator 113 _l and 113 _R connected.

The coolers 113 _l and 113 _R are arranged above the left and right machine blocks B _L and B _R , that is, both cylinder bore rows 22 _l and 22 _R , The outlets of both coolers 113 _l and 113 _R are with the first suction opening 106 the water pump 94 connected.

If this cooling water circuit is in a condition where the temperature of the cooling water is low before the engine warms up, the thermostat will close 102 the thermostatic valve 104 and opens the bypass valve 105 , so that from the outlet opening 108 the water pump 94 discharged cooling water from the water mantles 109 _l . 110 _l . 109 _R and 110 _r in the water pump 94 is sucked, not through the radiator 113 _l and 113 _R , Then, when the temperature of the cooling water becomes higher after the engine warms up, the thermostat opens 102 the thermostatic valve 104 and closes the bypass valve 105 , so that from the outlet opening 108 the water pump 94 discharged cooling water from the water mantles 109 _l . 110 _l . 109 _R and 110 _r through the coolers 113 _l and 113 ₈ in the water pump 94 is sucked. That is, the cooling water circuit with bottom bypass using the thermostat 102 is between the water pump 94 , the water-coats 109 _l . 109 _R . 110 _l and 110 _r and the coolers 113 _l and 113 _R educated.

A swing valve 114 for draining air in the water pump 94 from the first suction opening 106 is at the upper portion of the carrier plate 103 of the thermostat 102 above the impeller 99 appropriate.

Now especially 13 , One with the crankshaft 29 coupled main shaft 115 , a countershaft 116 with a plurality of gear trains, which can be selectively inserted and between the main shaft 115 and the countershaft 116 are provided, and an output shaft 117 connected to the countershaft via a one-way clutch (not shown) 116 is coupled, are rotatable on the transmission housing 90 stored. Each of the waves 115 . 116 . 117 is axially parallel to the crankshaft 29 arranged. The output shaft 117 for power transmission to the rear wheel of the motorcycle is from the back of the gear housing 90 backwards in front.

A switching shaft 119 for axially movably supporting a plurality of switching elements 118 for optional insertion of the gear trains between the main shaft 115 and the countershaft 116 is on the gearbox 90 under and between the main shaft 115 and the countershaft 116 stored. A switching drum 120 for selectively moving one of the switching elements 118 is on the gearbox 90 adjacent the shift shaft 119 rotatably mounted about its own axis.

An engine 121 whose axis of rotation is parallel to the axis of the crankshaft 29 runs, is at the back of the gearbox 90 above and between the crankshaft 29 and the output shaft 117 appropriate. An intermediate wave 122 is on the gearbox 90 between the crankshaft 29 and the engine 121 stored. A gear train (not shown) that transmits torque from the engine 121 on the crankshaft 29 allows, but no torque transmission from the crankshaft 29 on the engine 121 is possible between the engine 121 and the crankshaft 29 provided, wherein the intermediate shaft 122 interposed, so that the power of the engine 121 when starting the engine on the crankshaft 29 is transmitted.

A power transmission mechanism 123 , which is operated in reverse, is between the engine 121 and the output shaft 117 intended. The mechanism 123 Used for torque transmission from the engine 121 on the output shaft 117 when the driver switches to reverse, and to rotate the output shaft 117 in the direction opposite to that for forward motion. The reverse drive power transmission mechanism 123 interrupts the power transmission from the output shaft 117 to the engine 121 , if not switched to reverse.

One with the crankshaft 29 coupled power generator 124 is at the back of the gearbox 90 parallel to the axis of the crankshaft 29 appropriate. One with the main shaft 115 coaxial coupling 125 that the crankshaft 29 with the main shaft 115 is detachable, is at the back of the gearbox 90 arranged. That is, the power generator 124 and the clutch 125 are at the back of the gearbox 90 parallel to the water pump 94 coaxial to the crankshaft 29 arranged.

An oil pump 126 that with the main shaft 115 via a power transmission mechanism 128 , such as a chain, is in the lower portion of the transmission housing 90 intended. From the oil pump 126 discharged oil becomes the respective portions to be lubricated of the engine main body E via an oil filter 127 (please refer 2 ) fed to the front of the transmission housing 90 is provided. The oil channels 55 _l and 55 _R located in the left and right cylinder blocks 23 _l and 23 _r and the left and right cylinder heads 24 _l and 24 _R are provided to the oil to be lubricated portions of the camshaft 46 _l and 46 _R to feed, are with the oil filter 127 connected.

Now back to the 1 and 2 , A main frame (not shown) of the motorcycle has footpegs 130 _l and 130 _r on which the driver can put his feet. The footpegs 130 _l and 130 _r are on left and right sections behind and under the left and right cylinder heads 24 _l and 24 _R of the machine main body E so as to protrude therefrom to the left and to the right. The inside end of the respective footpegs 130 _r and 130 _l is in the width direction of the motorcycle from the opening at the outer end of the respective outlet channels 35 _l and 35 _R in the cylinder heads 24 _l and 24 _R is formed, offset by a distance L7 inward.

To prevent the movement of the driver's feet on the notches 130 _l and 130 _r through the left and right cylinder heads 24 _l and 24 _R and the left and right head covers 60 _l and 60 _R is hampered, their lower rear corners are cut off, as with the reference number 131 specified.

The function of this embodiment will be described below. In the multi-cylinder (eg six-cylinder) engine with horizontally opposed cylinders is a pair of left and right cylinder bore rows 22 _l and 22 _R on both sides of the crankshaft 20 arranged extending substantially in the horizontal direction; the left cylinder bore row 22 _l (or the right cylinder bore row 22 _R ) is of a plurality (eg, three) of the cylinder bores 21 _l (or 21 _r composed, which are arranged in parallel; and the camshaft 46 _l (or 46 _R ), the cylinder bore series 22 _l (or 22 _R ), is above a level 38 _l (or 38 _R ), which are the axes of the cylinder bores 21 _l (or 21 _r ) and the axis of the crankshaft 29 contains. Consequently, this is the camshaft 46 _l (or 46 _R ) containing valve mechanism from the axial lines of the cylinder bores 21 _l (or 21 _r ) offset upward so that the cylinder head 24 _l (or 24 _R ) can be formed so that a sufficient space is ensured under the valve mechanism corresponding area. In other words, you get under the cylinder head 24 _l (or 24 _R ) a relatively large space.

In the case of mounting a multi-cylinder engine with opposed cylinders on the motorcycle such that the axis of the crankshaft 29 runs in the longitudinal direction of the motorcycle and the cylinder heads 24 _l and 24 _R on both sides of the motorcycle protrude in the width direction, you get enough free space, so that the driver's feet under the cylinder heads 24 _l and 24 _R can sit down, and you get a relatively large angle of inclination α of the motorcycle.

The pairs of intake valves 36 _l (or 36 _R ) and the exhaust valves 37 _l (or 37 _R ) for each cylinder bore 21 _l (or 21 _r ), ie for each combustion chamber 26 _l (or 26 _R ), are parallel to each other and from the plane 38 _l (or 38 _R ) are offset upwards, and they are by the on the camshaft 46 _l (or 46 _R ) provided inlet side cam 48 _l (or 48 _R ) and exhaust cams 49 _l (or 49 _R ) directly opened and closed. Accordingly, the valve mechanism for driving the intake valves 36 _l (or 36 _R ) and the exhaust valves 37 _l (or 37 _R ) be significantly simplified. Furthermore, the camshafts 46 _l and 46 _R for the respective cylinder bore rows 22 _l and 22 _R are arranged, the cylinder heads can 24 _l and 24 _R be made compact.

As the intake valves 36 _l (or 36 _R ) and the exhaust valves 37 _l (or 37 _R ) in the cylinder head 24 _l (or 24 _R ) at an acute angle with respect to the plane 38 _l (or 38 _R ) are inclined, the top wall surfaces of the respective combustion chambers 26 _l (or 26 _R ) can be performed roof-shaped or hemispherical in order to set the S / V ratio or space velocity ratio to a relatively small value.

On the side, the arrangement side of the intake valves 36 _l ( 36 _R ) and the exhaust valves 37 _l (or 37 _R ) in relation to the plane 38 _l (or 38 _R ), ie below the plane 38 _l (or 38 _R ) are the spark plugs 39 _l (or 39 _R ) leading to the combustion chamber 26 _l (or 26 _R ), on the cylinder head 24 _l (or 24 _R ) appropriate. In this case, the intake valves 36 _l (or 36 _R ) and the exhaust valves 37 _l (or 37 _R ) at an acute angle with respect to the plane 38 _l (or 38 _R ), one obtains, a relatively large free space on the side, the arrangement side of the intake valves 36 _l (or 36 _R ) and the exhaust valves 37 _l (or 37 _R ) in relation to the plane 38 _l (or 38 _R ), ie below the plane 38 _l (or 38 _R ), whereby further the spark plugs 39 _l (or 39 _R ) relatively easily to the central portions of the combustion chambers 26 _l (or 26 _R ) can be arranged pointing while a fault with the intake valves 36 _l (or 36 _R ) and the exhaust valves 37 _l (or 37 _R ) is avoided to the degree of freedom in the arrangement of the spark plugs 39 _l (or 39 _R ) increase.

The spark plugs 39 _l (or 39 _R ) are at an acute angle with respect to the plane 38 _l (or 38 _R ) inclined. Because of the angle of inclination of the spark plugs 39 _l (or 39 _R ) the intake valves 36 _l (or 36 _R ) and the exhaust valves 37 _l (or 37 _R ) at an acute angle with respect to the plane 38 _l (or 38 _R ) are inclined, the spark plugs can be 39 _l (or 39 _R ) so that they are to the middle sections of the combustion chambers 26 _l (or 26 _R ) while malfunctioning with the camshafts 46 _l (or 46 _R ) is avoided without the inclination angle of the spark plugs 39 _l (or 39 _R ) Too big.

The cylinder head 24 _l (or 24 _R ) contains the inlet channels 34 _l (or 34 _R ), which are the side surface of the cylinder head 24 _l (or 24 _R ) at the above level 38 _l (or 38 _R ), and further includes the outlet channels 35 _l (or 35 _R ), which extend to the other side surface of the cylinder head 24 _l (or 24 _R ) at the below the level 38 _l (or 38 _R ). That is, because the intake valves 36 _l (or 36 _R ) and the exhaust valves 37 _l (or 37 _R ) are arranged so that they are to the side surfaces of the cylinder head 24 _l (or 24 _R ) on both sides of the plane 38 _l (or 38 _R ), the inlet system can be opened 66 and the exhaust system 43 _l (or 43 _R ) in a simple way with the cylinder head 24 _l (or 24 _R ) connect.

In projection plane orthogonal to the axes of the cylinder bores 21 _l (or 21 _r ) are the inlet channels 34 _l (or 34 _R ) in the cylinder head 24 _l (or 24 _R ) arranged such that they are the plane 38 _l (or 38 _R ) cut substantially at right angles. That is, because the intake ports 34 _l (or 34 _R ) are substantially rectilinear and to the combustion chambers 26 _l (or 26 _R ) are slightly curved, the inlet resistance can be at the inlet channels 34 _l (or 34 _R ) to improve the charging effect.

The outlet channels 35 _l (or 35 _R ) are in the cylinder head 24 _l (or 24 _R ) to one end side of the camshaft 46 _l (or 46 _R ), ie, curved or bulged toward the front of the motorcycle, around the spark plugs 39 _l (or 39 _R ) to get around. As a result, the flow resistance in the outlet channels 35 _l (or 35 _R ) greater than in the inlet channels 34 _l (or 34 _R ); however, there is no problem because the exhaust gas from the combustion chambers 26 _l (or 26 _R ) is under pressure.

Because the camshaft 46 _l (or 46 _R ) above the axial line of the cylinder bore row 22 _l (or 22 _R ) is arranged and further the outlet channels 35 _l (or 35 _R ) bypassing the spark plugs 39 _l (or 39 _R ) are curved to the front, it is probemlos a free space so that the driver can put his feet in a position behind and below the motorcycle mounted on the machine with horizontally facing cylinders.

Since the outlet channels 35 _l (or 35 _R ) to the underside of the cylinder head 24 _l (or 24 _R ) open down, are also the spark plugs 39 _l (or 39 _R ) on the cylinder head 24 _l (or 24 _R ) are mounted so that they are inclined downwards. Accordingly, with the motorcycle-mounted multi-cylinder engine having horizontally opposed cylinders, the appearance of the spark plugs is possible 39 _l (or 39 _R ) and to improve their environment, easily dissipate water in the vicinity of the spark plugs 39 _l (or 39 _R ) on the outer surface of the cylinder head 24 _l (or 24 _R ) has penetrated, and easily the exhaust pipes 41 _l (or 41 _r ), with the exhaust ducts 35 _l (or 35 _R ) to relocate.

Further, since the lid portion 62 _l (or 62 _R ) for covering the spark plugs 29 _l (or 29 _R ) from the outside integrally with the left head de ckel 60 _l (or right head cover 60 _R ) is formed, with the left cylinder head 24 _l (or the right cylinder head 24 _R ) with the valve system chamber 61 _l (or 61 _r ) for receiving the camshaft 46 _l (or 46 _R ), it is possible to change the appearance of the spark plugs 39 _l (or 39 _R ) and their surroundings.

Because the outlet channels 35 _l (or 35 _R ) in the cylinder head 24 _l (or 24 _R ) are arranged so that they are inclined in the width direction to the transverse center of the motorcycle and open down and thereby the exhaust pipes 41 _l (or 41 _r ), with the outlet channels 35 _l (or 35 _R ), can be arranged near the transverse center of the motorcycle, can be a restriction of the skew angle α of the motorcycle due to the exhaust pipes 41 _l (or 41 _r ) to thereby ensure a sufficient skew angle α.

Furthermore, the exhaust pipes 41 _l (or 41 _r ) are inclined so that they with increasing distance down from the cylinder head 24 _l (or 24 _R ) come together to the transverse center of the motorcycle and with the outlet channels 35 _l (or 35 _R ) are connected, can also be the limitation of the skew angle α of the motorcycle due to the exhaust pipes 41 _l (or 41 _r ) to ensure a sufficient skew angle α.

Because the exhaust valves 37 _l (or 37 _R ) above the level 38 _l (or 38 _R ) are arranged while the exhaust ducts 35 _l (or 35 _R ) to the bottom of the cylinder head 24 _l (or 24 _R ), it is possible a relatively large distance between the respective combustion chambers 26 _l (or 26 _R ) and the open end of the associated outlet channel 35 _l (or 35 _R ), which extend to the lower surface of the cylinder head 24 _l (or 24 _R ), and also the curvature of the exhaust ducts 35 _l (or 35 _R ) within the axis of the crankshaft 29 orthogonal plane to make relatively low, although the outlet channels 35 _l (or 35 _R ), tilting toward the transverse center of the motorcycle, thereby reducing an increase in exhaust resistance.

The lid section 62 _l (or 62 _R ), the integeral with the left head cover 60 _l (or right head cover 60 _R ), has the function, connecting portions of the outlet channels 35 _l (or 35 _R ) with the exhaust pipes 41 _l (or 41 _r ) from the outside. This improves the appearance of the connecting portions of the outlet channels 35 _l (or 35 _R ) to the exhaust pipes 41 _l (or 41 _r ). Furthermore, the exhaust pipes 41 _l (or 41 _r ) from the lid section 62 _l (or 62 _R ) are separated, since they point downwards, leaves a thermal deterioration of the lid portion 62 _l (or 62 _R ), even if the head cover 60 _l (or 60 _R ) is made of synthetic resin.

What the inlet channels 34 _l and the outlet channels 35 _l concerns the left cylinder head 24 _l are provided, and the inlet channels 34 _R and the outlet channels 35 _R in the right cylinder head 24 _R are provided, the relative positional relationship between the intake ports 34 _l and the outlet channels 35 _l along the axial direction of the crankshaft 29 designed so that they are almost equal to the relative positional relationship between the inlet channels 34 _R and the outlet channels 35 _R along the axial direction of the crankshaft 29 is. This allows a simplification of the structures of the intake system 66 and the exhaust systems 43 _l and 43 _R ,

To the cylinder head 24 _l (or 24 _R ) on the cylinder block 23 _l (or 23 _r ), has the cylinder head 24 _l (or 24 _R ) below the level 38 _l (or 38 _R ) a plurality of through holes 56 _l (or 56 _R ) at a distance in the axial direction of the camshaft 46 _l (or 46 _R ). The fastening bolts 57 _l (or 57 _R ) are in the through holes 56 _l (or 56 _R ). Further, each through hole is 56 _l (or 56 _R ) on one end side of the camshaft 46 _l (or 46 _R ) the one associated exhaust duct 35 _l (or 35 _R ) adjacent to the spark plug 39 _l (or 39 _R ) for the combustion chambers 26 _l (or 26 _R ) bypasses. This through hole 56 _l (or 56 _R ) has such a positional relationship that a distance L4 between a center of the through hole 56 _l (or 56 _R ) and a center C _L (the C _R ) of the associated combustion chamber 26 _l (or 26 _R ) is greater than a value L3. The value L3 denotes half the distance between the centers C _L (or C _R ) of adjacent combustion chambers 26 _l (or 26 _R ). This allows a relatively small curvature of the outlet channels 35 _l (or 35 _R ) bypassing the spark plugs 39 _l (or 39 _R ), and prevents the flow resistance of the outlet channels 35 _l (or 35 _R ) increases excessively.

On the side of the inlet valves 36 _R and the exhaust valves 37 _R in terms of the level 38 _R , owns the right cylinder head 24 _R a plurality of through holes 59 _R at a distance in the axial direction of the camshaft 46 _R , Of the several through holes 58 _R are the middle-side through holes 58 _R each between adjacent combustion chambers 26 _R arranged. A distance L5 between a center of the through hole 58 _R at the extreme end of one end side of the camshaft 46 _R is arranged, and the center C _{R of} the combustion chamber 26 _R located at the extreme end of one end side of the camshaft 46 _R is less than the value L3. The value L3 is, as described above, half the distance between the centers C _{R of} adjacent combustion chambers 26 _R , As a result, the end portion of the cylinder head 24 _R on the one end side of the camshaft 64 _R as close as possible to the center C _{R of} the combustion chamber 26 _R be approximated, at the extreme end of the curved side of the outlet channels 35 _R bypassing the spark 39 _R is arranged. This will change the length of the cylinder head 24 _R in the axial direction of the camshaft 46 _R as small as possible.

The camshaft 46 _l (or 46 _R ) is at several locations at a distance from each other in the axial direction of the camshaft 46 _l (or 46 _R ) through the cam bearing sections 50 _l (or 50 _R ) attached to the cylinder head 24 _l (or 24 _R ) are provided, and the cam holder 51 _l (or 51 _R ) attached to the cam bearing sections 50 _l (or 50 _R ) are mounted, rotatably mounted. The control mechanism 68 _l (or 68 _R ) for halving the speed of the crankshaft 29 and transmitting the reduced speed to the camshaft 46 _l (or 46 _R ) is between the crankshaft 29 and the camshaft 46 _l (or 46 _R ) intended. In the camshaft 46 _l (or 46 _R ) is the oil channel 52 _l (or 52 _R ) provided, the oil from the oil passage 55 _l (or 55 _R ), in the cylinder head 24 _l (or 24 _R ) and the cylinder block 23 _l (or 23 _r ) is provided. At the side of the left cylinder head 24 _l gets oil from the oil groove 54 _l at the extreme end on one end side of the camshaft 46 _l arranged cam bearing section 50 _l is provided in the oil passage 52 _l in the camshaft 46 _l through that in the camshaft 46 _l trained oil hole 53 _l directed. At the side of the right cylinder head 24 _R is the oil groove 54 _R for passing oil into the oil channel 52 _R in the camshaft 46 _R through that in the camshaft 46 _R trained oil hole 53 _R in the cam bearing portion 50 _R formed, which is provided in the cylinder head, that of the combustion chamber 26 _R corresponds to that in the axial direction of the camshaft 46 _R arranged several combustion chambers 26 _R the control mechanism 68 _R is closest.

With this arrangement of the oil groove 54 _R Is it possible to add oil to the oil channel 52 _R in the camshaft 56 _R to guide, without limitation, the arrangement of the fastening bolts 57 _R and 59 _R for fixing the right cylinder head 24 _R on the right cylinder block 23 _r ,

The cam bearing section 50 _R , the one among the several, on the right cylinder head 24 _R provided cam bearing sections 50 _R the control mechanism 68 _R is closest, has a through hole 58 _R into which the fastening bolt 59 _R under the fastening bolts 55 _R and 59 _R for fixing the cylinder head 24 _R on the cylinder block 23 _r is to use. As a result, the fastening bolt between the control mechanism 68 _R and the combustion chamber 26 _R as close as possible to the combustion chamber 26 _R brought so that the length of the cylinder head 24 _R along the axial direction of the camshaft 46 _R shorten.

The camshaft 46 _R on the right cylinder head 24 _R appropriate control mechanism 68 _R is in the axial direction of the crankshaft 29 on the camshaft 46 _l on the left cylinder head 24 _l corresponding control mechanism 68 _l offset to the front. In other words, the extreme end of the one end side of the camshaft 46 _R is from that of the camshaft 46 _l offset forward, and the control mechanism 68 _R is at the extreme end of the one end side of the camshaft 46 _R connected. The above through hole 48 _R and the above oil groove 54 _R are in two of the several cam bearing sections 50 _R the camshaft 46 _R intended. As a result, it is possible to control the length between the control mechanism 68 _R and the combustion chamber 26 _R shorten, thereby reducing the length of the multi-cylinder engine in the axial direction of the camshaft 46 _l (or 46 _R ) significantly shorten.

The two cylinder bore rows 22 _l and 22 _R are in the axial direction of the crankshaft 29 offset from each other, and both control mechanisms 68 _l and 68 _R are arranged such that the gap L6 between them is smaller than the first offset amount L1 between the cylinder bores 22 _l and 22 _R , As a result, it is possible to control the distance between both control mechanisms 68 _l and 68 _R to make smaller, thereby the length of the engine main body E in the axial direction of the camshaft 46 _l (or 46 _R ) to make smaller.

Furthermore, since both control mechanisms 68 _l and 68 _R between the one end portion of the crankshaft 29 and the one end portion of the camshaft 46 _l or the one end portion of the crankshaft 29 and the one end portion of the camshaft 46 _R are provided, it is possible the distance between both control mechanisms 68 _l and 68 _R free to choose.

The outer end opening of the respective outlet channels 35 _R (or 35 _R ), which extend to the lower surface of the left cylinder head 24 _l (or right cylinder head 24 _R ), is from the center C _L (or C _R ) of the associated combustion chamber 26 _l (or 26 _R ) to one end side of the camshaft 46 _l (or 46 _R ), ie to the control mechanism 68 _l (or 68 _R ). As a result, the exhaust systems 43 _l and 43 _R , each with the outlet channels 35 _l and 35 _R effectively using the space between both control mechanisms 68 _l and 68 _R be arranged so that the entire machine including the exhaust systems 43 _l and 43 _R can be made compact.

Because both control mechanisms 68 _l and 68 _R are arranged at the front portion of the engine main body E, one obtains a relatively large clearance behind and under the left and right cylinder heads 24 _l and 24 _R so that the footpegs 130 _l and 130 _r on which the driver puts his feet, without any difficulty behind the left and right cylinder heads 24 _l and 24 _R disposed can be. Further, because the inner end portion of the respective footpegs 130 _l and 130 _r from the outer end opening of the respective exhaust pipes 35 _l and 35 _R is offset in the width direction of the motorcycle inward, the supernatant amounts of the footrests 130 _l and 130 _r in the width direction of the motorcycle as small as possible, so that a restriction of the skew angle α by the footrests 130 _l and 130 _r can be reduced.

The control mechanism 68 _l (or 68 _R ) forms a power transmission using the chain 71 _l (or 71 _R ). The associated control chamber 72 _l ( 72 _R ), one end of which with the valve system chamber 61 _l (or 61 _r ) and the other end to one end of the crankshaft 29 points and the the control mechanism 68 _l (or 68 _R ), he stretches from the head cover 60 _l (or 60 _R ) to the crankcase 27 _l (or 27 _R ) over the cylinder head 24 _l (or 24 _R ) and the cylinder block 23 _l (or 23 _r ). The other end of the control chamber 72 _l (or 72 _R ) stands with the crank chamber 28 in connection.

Unlike a belt control mechanism, this allows the control mechanism 68 _l (or 68 _R ) containing control chamber 72 _l (or 72 _R ) that oil flows through it. As a result, without special means for preventing oil leakage from the crankcase 27 _l (or 27 _R ) to the side of the control chamber 72 _l (or 72 _R ), in particular without a sealing structure on the crankcase 27 _l (or 27 _R ), which makes the machine compact.

Furthermore, the camshaft 46 _l (or 46 _R ) over the crankshaft 29 is arranged, the oil in the valve system 61 _l (or 61 _r ) to the crankshaft side 29 at a lower level through the control chamber 72 _l (or 72 _R ) flow. This facilitates the return of the oil in the valve system chamber 61 _l (or 61 _r ) to the side of the crankcase 27 _l (or 27 _R ).

For connecting the bottom portions of the other ends of the control chambers 72 _l and 72 _R with the interior of the crank chamber 28 , is the return hole 85 in the left and right crankcases 27 _l and 27 _R intended. As a result, special oil return channels are unnecessary for the cylinder blocks 23 _l and 23 _r and the cylinder heads 24 _l and 24 _R for the oil return from at least the control chambers 72 _l and 72 _R in the crank chamber 28 , and consequently, the cylinder blocks 23 _l and 23 _r and the cylinder blocks 24 _l and 24 _R be made compact with less weight.

The crankshaft 29 is on a plurality of bearing walls 31 , which is integral with the left crankcase 29 _l are formed, and a plurality of bearing caps 32 standing at the warehouse walls 31 are fixed, rotatably mounted. The return hole 85 is along the mounting direction of the bearing caps 32 on the storage walls 31 educated. As a result, it is possible to open the opening area of the return hole 85 make relatively large, without the load capacity of the crankshaft 29 to thereby reduce the return characteristics of the oil in the crank chamber 28 to improve.

The return hole 35 is in both left and right crankcases 27 _l and 27 _R designed so that it is to the side of the left crankcase 27 _l is offset. As a result, it is possible to open the opening area of the return hole 85 make larger while a decrease in the strength of the crankcase to which the bearing walls 31 are not formed integrally, is avoided, ie in the right crankcase 27 _R to further improve the return properties of the oil.

In the control mechanism 68 _l that is between the left camshaft 46 _l and the crankshaft 29 is provided, is the chain tensioner 79 _l moving along the running direction of the chain 71 _l extends, elastically displaceable in contact with the chain 71 _l , The one longitudinal end of the chain tensioner 79 _l is on that camp cap 32 under the several bearing caps 32 rotatably mounted, which is the control mechanism 68 _l is closest. With this configuration you can see the position of the pivot bearing of the chain tensioner 79 _l choose more freely and the movement of the chain 71 _l To effectively restrict, by the chain tensioner 79 _l makes relatively long.

As the control mechanism 68 _l between an end portion of the camshaft 46 _l and the other end portion of the crankshaft 29 is provided, you need the position of the pivot bearing portion of the chain tensioner 79 _l at one point do not consider where the chain tensioner 79 _l not with a counterbalance of the crankshaft 29 disturbs. This allows easy positioning of the pivot bearing portion of the chain tensioner 79 _l ,

As one end of the chain tensioner 79 _l for the control mechanism 68 _l from the cylinder block 23 _l on which the bearing walls 31 are formed integrally, at the control mechanism 68 _l next camp cap 32 rotatably mounted, can be the pivot position of the chain tensioner 79 _l under effective use of one of the bearing caps 32 , which is necessarily provided for the multi-cylinder engine with horizontally opposed cylinders, easily set.

The pump shaft 95 the water pump 94 is directly to the other end of the crankshaft 29 connected, whose one end with both control mechanisms 68 _l and 68 _R is connected, ie the Hin terende of the crankshaft 29 in the longitudinal direction of the motorcycle, and the water pump 94 gets directly from the crankshaft 29 driven. As a result, one can do without a gear, a chain, a belt, etc. required for driving a conventional water pump, thereby the driving mechanism of the water pump 94 to simplify.

The pulser rotor 75 for detecting the rotational position of the crankshaft 29 is at the one end portion of the crankshaft 29 attached. By using the pulser rotor 75 is it possible to change the rotational position of the crankshaft 29 without interference by the water pump 94 easy to grasp.

Because the water pump 94 In the longitudinal direction of the motorcycle rear, a pipe system for cooling water, which is connected to the water pump 94 is connected to be arranged in an inconspicuous place.

Because the radiator 113 _l and 113 _R are each arranged over two machine blocks B _L and B _R , that is, over both cylinder bore rows 22 _l and 22 _R , the pipes or hoses for cooling water between the machine and both coolers 113 _l and 113 _R on the left and right sides almost the same length or even shorter.

As the power generator 124 and the clutch 125 parallel to the water pump 94 are arranged, it is not necessary, the length of the crankcase 29 for the arrangement of the power generator 124 and the clutch 125 to enlarge, although the water pump 94 directly from the crankshaft 29 is driven, and therefore it is possible for the machines in the axial direction of the crankshaft 29 compact.

The housing 96 the water pump 94 is formed of a pump body 97 for rotatably supporting the pump shaft 95 and the pump cover 98 that with the pump body 97 is connected so that it on the pump shaft 95 fixed impeller 99 covers. The thermostat 102 that is between the pump body 97 and the pump cover 98 is held in the pump cover 98 trained recording section 101 contain. If in addition the thermostat 102 in the water pump 94 is to be provided, it is possible to reduce the number of parts, and therefore to reduce the cost and weight and also to reduce the number of assembly steps.

The first suction opening 106 extending to one end of the receiving section 101 opens is in the pump body 97 provided so that they with the coolers 113 _l and 113 _R communicates, and the second suction port 107 extending to the other end of the receiving section 101 opens to water from the machine bypassing the radiator 113 _l and 113 _R is in the pump cover 98 intended. The thermostat 102 with the thermostatic valve 104 for opening / closing the first suction opening 106 and the bypass valve 105 for opening / closing the second suction opening 107 is in the receiving section 101 added. As a result, at low cooling water temperature, the thermostatic valve 104 closed and the bypass valve 105 opened, whereas with increasing cooling water temperature, the thermostatic valve 104 is opened and the bypass valve 105 is closed. Thus, you get a simple way a cooling water circuit with bottom bypass.

As the outlet opening 108 for discharging cooling water in response to the rotation of the impeller 99 in the pump cover 98 is provided, one obtains a simple way a circuit for introducing cooling water from the water pump 94 ,

Because the thermostat 102 above the impeller 99 is arranged, it is possible to air in the water pump 94 by means of the swing valve 114 of the thermostat 102 safely dissipate.

In summary the invention of an internal combustion engine, in between between cylinder bores slidably inserted pistons and a cylinder head combustion chambers are formed, wherein a camshaft with intake valves and exhaust valves to open / close coupled in the cylinder provided inlet channels and outlet channels is, and wherein between the crankshaft and the camshaft a Control mechanism is provided.

The intake valves 36 _l or 36 _R and the exhaust valves 37 _l or 37 _R are arranged in parallel at points, by a plane 38 _l or 38 _R passing through the axle lines of cylinder bores 21 _l or 21 _r and the axis line of a crankshaft 29 goes through, are offset to one side. cam 48 _l and 49 _l or 48 _R and 49 _R for direct opening / closing of intake valves 36 _l or 36 _R and the exhaust valves 37 _l or 37 _R are on the camshaft 46 _l or 46 _R provided parallel to the crankshaft 29 is arranged so that it the intake valves 36 _l or 36 _R and the exhaust valves 37 _l or 37 _R is common. As a result, the A laßventile and the exhaust valves can be opened / closed with a particularly simple mechanism.

Claims (8)

Internal combustion engine, in which between pistons provided in a cylinder block (B _L , B _R ) cylinder bores ( 21 _l . 21 _r ) are slidably inserted, and a cylinder head ( 24 _l . 24 _R ) Combustion chambers ( 26 _l . 26 _R ) are formed; wherein a camshaft ( 46 _l . 46 _R ) with inlet valves ( 36 _l . 36 _R ) and exhaust valves ( 37 _l . 37 _R ) for opening / closing inlet ducts ( 34 _l . 34 _R ) or outlet channels ( 35 _l . 35 _R ) coupled in the cylinder head ( 24L . 24 _R ) are arranged so that they communicate with the combustion chambers ( 26 _l . 26 _R ) keep in touch; and wherein a control mechanism ( 68 _l . 68 _R ) for halving the speed of a crankshaft ( 29 ) and for transmitting the reduced speed to the camshaft ( 46 _l . 46 _R ) between the crankshaft ( 29 ) and the camshaft ( 46 _l . 46 _R ) is provided; the inlet valves ( 36 _l . 36 _R ) and the exhaust valves ( 37 _l . 37 _R ) are arranged in parallel at locations which are of one level ( 38 _l . 38 _R ), which are defined by the axis lines of the cylinder bores ( 21 _l . 21 _r ) and the axis line of the crankshaft ( 29 ) passes, are offset to one side; and cams ( 48 _l . 49 _l ; 48 _R . 49 _R ) for directly opening / closing the intake valves ( 36 _l . 36 _R ) and the exhaust valves ( 37 _l . 37 _R ) on the camshaft ( 46 _l . 46 _R ) are provided, which are parallel to the crankshaft ( 29 ) is arranged such that it the intake valves ( 36 _l . 36 _R ) and the exhaust valves ( 37 _l . 37 _R ) is common, characterized in that the axis lines of the cylinder bores ( 21 _l . 21 _r ) are arranged approximately in the horizontal direction; that the intake valves ( 36 _l . 36 _R ), the exhaust valves ( 37 _l . 37 _R ) and the camshaft ( 46 _l . 46 _R ) from the level ( 38 _l . 38 _R ) are offset upwards; and that the intake valves ( 36 _l . 36 _R ) and the exhaust valves ( 37 _l . 37 _R ) in relation to the level ( 38 _l . 38 _R ) are arranged inclined at an acute angle. Internal combustion engine according to claim 1, characterized in that on the side, the arrangement side of the intake valves ( 36 _l . 36 _R ) and the exhaust valves ( 37 _l . 37 _R ) with regard to the level ( 38 _l . 38 _R ), spark plugs ( 39 _l . 39 _R ) on the cylinder head ( 24 _l . 24 _R ) are mounted in such a way that they lead to the middle sections of the combustion chambers ( 26 _l . 26 _R ) point. Internal combustion engine according to claim 1 or 2, characterized in that the inlet ducts ( 34 _l . 34 _R ) and the outlet channels ( 35 _l . 35 _R ) to side surfaces of the cylinder head ( 24 _l . 24 _R ) on both sides of the plane ( 38 _l . 38 _R ) to open. Internal combustion engine according to claim 3, characterized in that of the inlet channels ( 34 _l . 34 _R ) and the outlet channels ( 35 _l . 35 _R ) those channels ( 35 _l . 35 _R ) extending to the side surface of the cylinder head ( 24 _l . 24 _R ), which in relation to the plane ( 38 _l . 38 _R ) the arrangement side of the intake valves ( 36 _l . 36 _R ) and the exhaust valves ( 37 _l . 37 _R ) is opposite, on one end side of the camshaft ( 46 _l . 46 _R ) are curved and / or bulged so that they the spark plugs ( 39 _l . 39 _R ) in the cylinder head ( 24 _l . 24 _R ) are mounted in such a way that they lead to the combustion chambers ( 26 _l . 26 _R ) point. Internal combustion engine according to claim 4, characterized in that on the side, with respect to the plane ( 38 _l . 38 _R ) the arrangement side of the intake valves ( 36 _l . 36 _R ) and the exhaust valves ( 37 _l . 37 _R ) is opposite, the cylinder head ( 24 _l . 24 _R ) a plurality of through holes ( 56 _l . 56 _R ), including those respectively at the corresponding section between the adjacent combustion chambers ( 26 _l . 26 _R ) are arranged, wherein the plurality of through holes ( 56 _l . 56 _R ) at intervals in the axial direction of the camshaft ( 46 _l . 46 _R ) are arranged such that fastening bolts ( 57 _l . 57 _R ) for fastening the cylinder head ( 24 _l . 24 _R ) on the cylinder block ( 23 _l . 23 _r ) can be used; and wherein a distance (L2) between a center of said one through-hole ( 56 _l . 56 _R ) that the spark plugs ( 39 _l . 39 _R ) on one side of the camshaft ( 46 _l . 46 _R ) immediate channels ( 35 _l . 35 _R ) and a center (C _L , C _R ) of one of the channels ( 35 _l . 35 _R ) associated combustion chambers ( 26 _l . 26 _R ) is greater than half of a distance (2L3) between the centers (C _L , C _R ) of adjacent ones of these combustion chambers ( 26 _l . 26 _R ). Internal combustion engine according to claim 4 or 5, characterized in that on the arrangement side of the intake valves ( 36 _R ) and the exhaust valves ( 37 _R ) with regard to the level ( 38 _R ) the cylinder head ( 24 _R ) a plurality of through holes ( 58 _R ), including those between each adjacent combustion chambers ( 26 _R ) are arranged, wherein the plurality of through holes ( 58 _R ) in the axial direction of the camshaft ( 46 _R ) are arranged at such intervals that fastening bolts ( 59 _R ) for fastening the cylinder head ( 24 _R ) on the cylinder block ( 23 ) can be used; and wherein a distance (L5) between the center of the one at the extreme end on the one end side of the camshaft ( 46 _R ) arranged through hole ( 58 ) and the center (C _R ) of the one at the extreme end of the one end side of the camshaft ( 46 _R ) arranged combustion chamber ( 26 _R ) is less than half of a distance (2L3) between the centers (C _R ) of adjacent combustion chambers ( 26 _R ). Internal combustion engine according to one of claims 1 to 6, characterized in that a valve system chamber ( 61 _l . 61 _r ) between the cylinder head ( 24 _l . 24 _R ) and a head cover ( 60 _l . 60 _R ) is designed in such a way that it matches that of the plane ( 38 _l . 38 _R ) upwardly offset camshaft ( 46 _l . 46 _R ) receives; one end of a control chamber ( 72 _l . 72 _R ) for receiving the control mechanism ( 68 _l . 68 _R ) with the valve system chamber ( 61 _l . 61 _r ), the control mechanism ( 68 _l . 68 _R ) of the is configured such that an endless chain ( 71 _l . 71 _R ) around one end of the crankshaft ( 29 ) fixed drive pinion ( 69 _l . 69 _R ) and one at the one end of the camshaft ( 46 _l . 46 _R ) fixed output pinion ( 70 _l . 70 _R ) is lying around; and wherein the lower portion of the other end of the control chamber ( 72 _l . 72 _R ) with the crankcase ( 27 _l . 27 _R ). Internal combustion engine according to one of claims 1 to 7, characterized in that the engine is mounted such that a plurality of cylinder bores ( 21 _l . 21 _r ) are arranged in parallel; wherein a pair of cylinder bore rows ( 22 _l . 22 _R ) on both sides of the crankshaft ( 29 ) is arranged opposite one another; wherein a plurality of the inlet valves ( 36 _l . 36 _R ) and a plurality of the exhaust valves ( 37 _l . 37 _R ) are arranged in parallel such that they are separated from the plane ( 38 _l . 38 _R ) of each of the cylinder bore rows ( 22 _l . 22 _R ) are offset upwards; and wherein the one end of the crankshaft ( 29 ) is to be arranged in the axial direction on the front of a motorcycle.