Internal combustion engine with a cam angle sensor means

Abstract: Internal combustion engine comprising a cylinder head and at least one camshaft supported on a cylinder head by a camshaft bearing means having at least one cam cap, and a cam angle sensor means for detecting a rotation angle of said camshaft. Said cam angle sensor means comprises at least one cam angle sensor attached to said cam cap.

Description: This invention relates to an internal combustion engine according to the preamble of independent claim 1. A cam mechanism or device is used as a valve driving system or device for four-stroke engines. In a DOHC type multi-cylinder engine, an intake and an exhaust camshaft are held. Said camshafts have journal sections provided one for each cylinder. Said camshafts are rotationally held on a cylinder head by cam caps for rotation, and covered by a head cover. In order to monitor valve timing of the engine by cams as described above, and to control said valve timing by a variable valve timing mechanism or device, there are provided cam angle sensors. The cam angle sensors are adapted to detect, for example, shutters provided radially on camshafts as angle detecting rotary sections of the camshafts. In a DOHC type valve engine, camshafts are provided over intake and exhaust valves, respectively, and the shutters are provided on intake and exhaust camshafts adapted to be rotated in synchronization with a crankshaft. The cam angle sensors are provided at positions facing the rotational circumferential surfaces of these shutters, for detection of passage of the rotating shutters. The rotational phases of the camshafts relative to the revolution of the crankshaft are detected based on detected signals of the rotation of the camshafts. The valve timing is controlled in response to the crank angle by advancing and delaying the phases of the camshafts to change cam angles. In this case, on a rotation transmission system or device from the crankshaft to the camshafts is mounted a VVT (variable valve timing mechanism or device) for shifting the rotational phases of camshafts relative to the revolution of the crank shaft to change the opening/closing timing of intake and exhaust valves. The VVT is a device in which phases of the camshafts are advanced or delayed by hydraulic mechanisms, and the direction of oil pressure is changed by switching valves of an electromagnetic solenoid type. Such a VVT, on which are installed cam sprockets for transmitting the rotation from the crankshaft, cam chains, etc, is provided at ends of parallel intake and exhaust camshafts (for example, at the forward ends when camshafts are disposed axially of the vehicle body). The conventional mounting structure of cam angle sensors has several types: type (1) in which the sensor is attached to the rear end of the engine opposite the VVT; type (2) in which the sensor is attached to a head cover; type (3) in which the sensor is attached to the cylinder head itself at the rear end of the engine; etc, the sensor being secured with a constant spacing from a shutter to be detected. However, in the foregoing structure of type (1) in which the sensor is attached to the rear end of the engine, the means supporting the sensor extends further rearward than the camshaft, so that the cylinder head extends rearwardly, resulting in a larger entire engine length. In the structure of type (2) in which the sensor is attached to a head cover, the position of the head cover is subject to change due to an elastic seal member provided between the head cover and the cylinder head, preventing adequate accuracy of the space between the sensor and the shutter. In order to keep the space at a fixed value, a position regulating spacer or the like made of a rigid material must be provided between a sensor mounting section or the head cover and the cylinder head, which partially lowers the vibration prevention effect of the head cover due to an elastic seal member, causing noises or the like. In the sensor mounting structure of type (3) in which the sensor is attached to the cylinder head itself, the sensor or its wiring may interfere with the side of the cylinder head or the intake system surrounding the lower section of the cylinder head, or may be brought close to the exhaust system to be subjected to heat damage. In order to avoid such a trouble, the degree of freedom of layout is restricted significantly, preventing a compact structure. Prior art document US 5,293,776 teaches a cylinder discrimination sensor layout having a sensor assembly being attached to the cam cover, wherein said cam cover is fixed to the cam bearing. Said sensor means comprises a sensor facing a specific cam of the camshaft in order to provide a pulse signal according to the rotational position of the camshaft. Said sensor can be provided to face the cam provided on the free end of the camshaft as well as cooperating with any other cam of the camshaft. Further prior art document US 5,988,126 teaches a device for varying valve timing of gas exchange valve.s of external combustion engines. Said engine comprises a camshaft, wherein a varying device is attached to the end of the camshaft. Furthermore, a pulse reading device is attached to a housing cap covering the valve timing device. An internal combustion engine as indicated above can be taken from prior art document EP 0 698 728 A1. In particular, said prior art document teaches an internal combustion engine with camshafts supported in a cylinder head by camshaft bearings. Said camshaft bearings include camshaft bearing caps attached to the cylinder head. An outermost camshaft bearing cap is provide with a sensor holder cooperating with a trigger wheel, which is provided on the camshaft. Said sensor holder is holding an angle sensor, wherein a cylinder mounting member is integrally provided within said sensor holder and directly attached to the cylinder head at an outermost portion thereof. Said sensor holder extends from the outermost bearing towards the outer side of the cylinder head, such that the trigger wheel is provided on the free end of the camshaft and cooperates with the angle sensor facing same. Furthermore, said internal combustion engine is provided with a variable valve timing device that is attached to the camshaft on the opposing side with regard to said angle sensor arrangement. Said variable valve timing device is adjacent to the drive pulley of the camshaft. It is an objective of the present invention to provide an internal combustion engine as indicated above having a rigid and compact structure. According to the present invention said objective is solved by an internal combustion engine according to independent claim 1. Advantageously, the cam angle sensor means for engines is capable of effecting spacially efficient arrangement without need of enlarging the entire engine length, by making use of the space above camshafts. Preferred embodiments of the present invention are laid down in the dependent claims. Hereinafter, the present invention is illustrated and explained in greater detail with respect to a preferred embodiment in conjunction with the accompanying drawings. In the drawings wherein: FIG. 1 is a top plan view showing one end of a cylinder head of an internal combustion engine according to an embodiment, with the cam cover removed, and with portions of the valve actuating mechanism eliminated in order to more clearly show the construction; FIG. 2 is a front elevational view of the structure shown in FIG. 1 and illustrates the cam cover in place and shows the control valve mechanism associated with the variable valve timing mechanism; FIG. 3 is a cross sectional view taken through the cylinder head and generally along the axis of one of the camshafts; FIG. 4 is a perspective view showing the bearing cap for the driven ends of the camshafts with the timing sensors or am angle sensor mounted therein; FIG. 5 is a perspective view looking from below showing one of the, the cam angle sensor sensors; FIG. 6 is a cross sectional view taken generally through the timing sensor and associated timing wheel formed integrally with one of the camshafts; and FIG. 7 is a schematic hydraulic diagram showing the lubricating oil passages and control mechanism for the intake and exhaust valve timing mechanisms. An embodiment of the internal combustion engine will be described below with reference to the accompanying drawings. Figs. 1-3 are a plan, a front and a side view of a cam angle sensor mounting structure according to the embodiment. Numeral 1 designates a DOHC type multi-cylinder four-valve engine, and in the figure is shown the forward end portion of a cylinder head 2 disposed in the longitudinal direction of the vehicle body. An unillustrated crankshaft of said engine is disposed in said longitudinal direction of the vehicle body. At the center of each cylinder is formed a plug hole 3 for mounting an ignition plug, around which are provided two intake valve holes or bores 4 and two exhaust valve holes or bores 5. In Fig. 1, a first cylinder in this forward end portion is shown. Upwardly of the intake valve holes 4 and the exhaust valve holes 5 are disposed in parallel an intake camshaft 6 and an exhaust camshaft 7, respectively. On these intake and exhaust camshafts 6, 7 are provided cams 8 corresponding to the respective valves. These camshafts 6,7 rotate about rotational axes (center axes), respectively. To the forward ends of these camshafts 6, 7 is attached a WT (variable timing mechanism) 9. The VVT 9 is comprised of an intake VVT 10 and an exhaust WT 11, as described below. Said VVT 9 is accommodated in a timing case of the cylinder head means. The upper surface of the cylinder head 2 together with the VVT 9 (Figs. 2, 3) is covered by a head cover 12. Fig. 1 is a view with the head cover omitted, and the peripheral edge portion of the cylinder head 2 constitutes a mating surface 13 with the head cover, on which is mounted the head cover 12 through a rubber seal (not shown). The intake and exhaust camshafts 6, 7 are supported on the cylinder head 2 for rotation at a first journal section 14 adjacent to the VVT 9, a second journal section 15, and further, a third, a fourth,...journal sections (camshaft bearing means) provided thereon corresponding to the respective cylinders, with their lower half portions fitted in the cylinder head. The upper half portions of these journal sections are covered by a plurality of cam caps (bearing caps), by which the camshafts 6, 7 are held for rotation on the cylinder head 2. In Figs. 1 to3 only a cam cap 17 of the first journal section 14 is shown; the further cam caps are unillustrated. In Fig. 1, on both sides of the second journal section 15 are formed cam cap mounting bolt holes 16, and on the first journal section 14 is mounted the cam cap 17 with integrated intake and exhaust sections, as described below. The cam cap 17 is shown by a heavy line in the figure. At axially spaced positions along its length, the intake and exhaust camshafts 6,7 are provided with bearing surfaces associated to the journal sections, respectively. Each camshaft has an end bearing surface, respectively. These end bearing surfaces are journalled in an upstanding front end wall of the cylinder head 2 which is adjacent the timing case. Said end bearing surfaces of the camshafts 6,7 are associated to the first journal section 14. The cylinder head 2 is connected to a cylinder body (not shown) with head bolts (threaded fasteners) 19 (Fig. 3) passing through head bolt holes (fastener holes) 18 (Fig. 1) provided around cylinders at four locations for each cylinder. The camshafts 6, 7 are disposed above these head bolts 19. These threaded fasteners 19 are passed through four fasteners holes 18 formed at the peripheral edges of the associated cylinder head 2 around each cylinder bore and threaded into tapped openings in the associated cylinder block to affix the cylinder head member 12 to the cylinder block in a manner that is well known in the art. The first journal sections 14 in the forward end portions of both camshafts 6, 7 support the intake VVT 10 and the exhaust VVT 11 in a cantilever fashion, respectively, so that they each have a large axial width. The cam cap 17 is mounted on the wide first journal sections 14. The cam cap 17, as shown in Fig. 4, is a cap with integrated intake and exhaust sections. The cam cap 17 is fixed to the cylinder head 2 with bolts (threaded fasteners) passing through bolt holes (openings) 20 on both sides of the first journal sections 14 of both camshafts and a bolt hole 22 provided in the connecting portion 21 of the cam cap between the intake and exhaust shafts. The cam cap 17 is provided with mounting seats (sensor mounting portions) 23 at positions corresponding to camshafts 6,7. The mounting seats 23 and the connecting portion 21 connecting intake and exhaust cam sections are formed overhanging towards the second journal sections 15 (see Fig. 3). A cam angle sensor 24 of a shape shown in Fig. 2 is mounted on each mounting seat 23. The cam angle sensor 24 is comprised of a cylindrical sensor body 25 and a mounting flange 26 projecting offset to one side of the sensor body 25 at the top thereof, and the mounting flange 26 is formed with a through hole 27 for the mounting bolt. The cam angle sensor 24 is fixed to the mounting base or seat 23, with the sensor body 25 inserted in a sensor insert hole 28 of the mounting base 23, and with a bolt through the through hole 27 of the mounting flange 26 screwed in a screw hole 29 of the mounting seat 23. The mounting seat 23, as shown in Figs. 2, 3, is exposed outside the head cover 12 through an elastic seal member 47 for connection of lead wires. A shutter or timing wheel 30 as a cam angle detecting section is provided on each of the camshafts 6, 7 between first and second journal sections 14, 15. The shutter 30 is rotary object to be detected by the cam sensor 24, and comprised of, for example, four radial projections 30a (four individual teeth or lugs). The cam sensor 24 is mounted, as shown in Figs. 1, 3, on the mounting seat 23 such that the center axis of the sensor body 25 crosses the axial center C of the camshaft 6 or 7, and the sensor body 25 is positioned facing the shutter 30 with a given space from the rotational surface (dotted line in Fig. 6) of the tips of the shutter 30. The mounting flanges 26 of both sensors 24 are protruded from the sensor bodies 25 laterally inwardly of both camshafts and toward the first journal sections 14. This arrangement of the mounting flanges 26 allows the cam cap 17 to be compact in its shape with small lateral and longitudinal dimensions. The shutter 30, which is an object to be detected by the cam angle sensor 24, is not limited to four projections shown as an example in the figure, but may be a wheel with a gear-like profile or a wheel with optical, electrical, or mechanical markings such as small projections or grooves. Sensors for detecting these shutters may be optical, electrical, mechanical, or any other types of sensors. Now, the VVT 9 will be described. A driving sprocket 31 is mounted on the intake VVT 10 and connected through a cam chain 32 to a sprocket on the unillustrated crankshaft. A coupling sprocket 33 is mounted coaxially with the driving sprocket 31 and connected to a coupling sprocket 35 of the exhaust VVT 11. Inside the connecting chain 34 between the coupling sprockets 33, 35 is provided a tensioner 36, which is fixed to the cylinder head 2 with two bolts. Via the rotation transmission system described above, the rotation of the crankshaft is transmitted to the driving sprocket 31 of the intake VVT 10 through the cam chain 32 and further to the exhaust VVT 11 through the coupling sprockets 33, 35 and the connecting chain 34. The intake and exhaust VVTs 10, 11 are provided with first oil pressure chambers 38 and second oil pressure chambers 39, and oil pressure supplied to either of the oil chambers allows the rotational phase of the camshafts 6, 7 to be shifted relative to those of the rotary shafts of the VVTs through said sprockets. Thus, the phases of the camshafts 6, 7 are adjusted relative to the crank angle to control the valve timing. Switching of oil pressure supply to the first and second oil chambers 38, 39 are performed by electromagnetic switching valves 40 provided in the intake and exhaust VVTs 10,11. Working oil, flowing in an oil passage 41 through a filter 42 as shown in Figs. 2, 7, is supplied through branched passages 46 to the switching valves 40 of the intake and exhaust VVTs 10, 11. Oil flows switched their directions in the switching valves 40, are supplied to the first oil chambers 38 or the second oil chambers 39 of the VVTs through first oil passages 43 or second oil passages 44 as shown in Fig. 7 to advance or delay the phases of the camshafts 6, 7. The branched passages 46 are further branched before switching valves to form lubricating oil passages 45, through which oil is supplied to both camshafts 6, 7, and to the cam cap 17 to lubricate thrust surfaces as described below. As shown in Fig. 3, on both sides of the first journal section 14 of the exhaust camshaft 7 are formed thrust bearings 48 (structure of the intake camshaft 6 is the same as that of the exhaust camshaft 7, and the same description will apply hereinafter to the intake camshaft 6), which receive thrust forces through the cylinder head 2 and the cam cap 17 supporting the camshaft 6 at this section to set the axial position of the camshaft. In the camshaft 7 is formed an oil passage 50 along the axial center. The branched passage 46 downstream of the filter 42 (Figs. 2, 7) is in communication with the oil passage 50 in the camshaft 7 through the oil passage 45, and oil is supplied from oil ports 50a in journal sections to journal bearing sections and the corresponding cam caps. The oil passages 45, 50 are in communication with thrust oil passage 49 formed in the cam cap 17. The thrust oil passage 49 has openings on both sides of the cam cap 17, through which oil is supplied to the thrust surfaces of the thrust bearings 48 on both sides. The branched passage 46, as described above, is divide through the switching valve 40 into the first and second oil passages 43, 44, which are in communication with oil passages 43a, 44a in the end portion of the camshaft. These oil passages 43a, 44a are in communication with the first and second oil chambers 38, 39 through oil ports 43b, 44b, respectively, and oil is supplied to the selected oil pressure chamber 38 or 39 to shift the phase of the camshaft relative to the crank angle. This embodiment provides a cam angle sensor mounting structure for engines comprising a VVT disposed at one ends of intake and exhaust camshafts of a multi-cylinder engine, said camshafts being held, at a plurality of journal sections formed thereon, on a cylinder head by a cam cap, cam angle detecting rotary sections on said camshafts, and cam angle sensors positioned facing said cam angle detecting rotary sections, wherein said cam angle detecting rotary section is provided between an outermost journal section adjacent to said VVT and a second journal section, and said cam angle sensor is attached to said cam cap on said outermost journal section. According to this embodiment, cam angle sensors are attached to a cam cap mounted on outermost journal sections adjacent to a WT, so that the cam angle sensors can be attached spacially efficiently without need of enlarging the entire engine length, by making use of the space above camshafts inside a head cover. In this case, sensors are attached and lead wires are connected through the head cover at a position adjacent to a large bulgy VVT provided at one end of the engine, so that portions which would be protruded from the head cover and have a bulgy shape, are dispensed with, effecting a spacially efficient simple layout. In addition, the sensors are attached to a cam cap on the outermost journal sections of the camshafts which has a large width to support the VVT in a cantilever fashion, so that even if the sensors are supported by the cam cap overhanging the second journal sections, they can be supported stably with sufficient strength. In addition, the cam angle sensors are provided on the cam cap at the upper portion away from the exhaust system, so that heat from the exhaust system is cut off and thermal influence on the sensors is mitigated, providing increased reliability of detection. According to the embodiment, said cam cap is configured such that its intake and exhaust cam cap sections are connected together between said intake and exhaust camshafts. According to this arrangement, the cam cap is formed such that it has an integrated shape extending between intake and exhaust camshafts, with its intake and exhaust cam cap sections connected together between intake and exhaust camshafts, and intake and exhaust cam sensors are attached to the intake and exhaust cam cap sections, respectively, so that sensors can be supported stably with sufficient strength. According to the embodiment, said cam angle sensor is disposed with its center axis crossing the axial center of the corresponding camshaft, and has a mounting flange offset from said center axis, said mounting flange being provided laterally on the side of said sensor inwardly of said camshafts and longitudinally on the side thereof close to said outermost journal section. According to this arrangement, when sensors are attached to a cam cap extending between parallel intake and exhaust camshafts, the center axes of sensors cross the axial centers of camshafts between outermost and second journal sections, and mounting flanges protruded offset from the center axes of the sensors to one sides thereof, are provided laterally on the sides of said sensors inwardly of said camshafts and longitudinally on the sides thereof close to the outermost journal sections, so that the cam angle sensors can be attached to the cam cap in a compact and stable manner without need of expanding the cam cap outwardly from both camshafts and of enlarging the overhang of the cam cap toward the second journal sections. According to the embodiment, axially on both sides of said outermost journal section are provided thrust bearings, and in said cam cap are formed oil passages for supplying oil on the surfaces of said thrust bearings, said oil passages and VVT driving oil passages being in communication with each other. According to this arrangement, thrust bearings are provided on both sides of the wide outermost journal sections adjacent to the VVT to hold the camshaft stably, the cam cap is mounted on these thrust bearings, in sliding contact with thrust bearing surfaces, and in the cam cap are formed thrust surface lubricating oil passages in communication with the WT driving passages, so that oil can be supplied on the thrust surfaces stably and reliably without complicating piping layout in the vicinity of the VVT. The embodiment described above teaches an internal combustion engine comprised of an engine body providing a number of axially spaced bearing sections, a plurality of axially spaced bearing caps fixed to said engine body and cooperating with said bearing sections for journalizing axially spaced bearing surfaces of a camshaft. A variable valve timing mechanism is associated with one end of said camshaft for driving said camshaft in an adjustable, timed fashion from an engine crankshaft. One of said journalled camshaft bearing surfaces is juxtaposed to said variable valve timing mechanism. A timing member is formed on said camshaft on the side of said one of said journalled camshaft bearing surfaces opposite to said variable valve timing mechanism. A timing sensor is cooperating with said timing member for providing a signal indicative of camshaft angle, wherein said timing sensor is carried by the bearing cap journalling said one of said journalled camshaft bearing surfaces. Said one journalled camshaft bearing surface is located at one end of the camshaft. The engine body is provided with a cover that encloses at least in part the camshaft and the bearing cap journalling said one of said journalled camshaft bearing surfaces and the timing sensor has a portion extending through said cover. The journalled camshaft bearing surface is bounded by a pair of thrust flanges engaged with the bearing cap journalling the one of said journalled camshaft bearing surfaces for axially locating the camshaft. The variable valve timing mechanism is hydraulically operated. The thrust flanges are lubricated from the same source as operates the variable valve timing mechanism. The lubricant for the thrust flanges is supplied through the bearing cap journalling the one of said journalled camshaft bearing surfaces. According to the embodiment, there is provided a further or second camshaft journalled about an axis parallel to the axis of the first mentioned camshaft by a second number of axially spaced bearing sections of the engine body. A second plurality of axially spaced bearing caps is fixed to said engine body and cooperating with said bearing sections for journalling axially spaced bearing surfaces of said second camshaft. A second variable valve timing mechanism associated with one end of said second camshaft for driving said second camshaft in an adjustable, timed fashion from the engine crankshaft, one of said journalled second camshaft bearing surfaces being juxtaposed to said second variable valve timing mechanism. A second timing member is formed on said second camshaft on the side of said one of said journalled second camshaft bearing surfaces opposite to said second variable valve timing mechanism. A second timing sensor is cooperating with said second timing member for providing a signal indicative of the camshaft angle of said second camshaft, wherein said second timing sensor is carried by the bearing cap of the second plurality journalling said one of said second journalled camshaft bearing surfaces. The bearing caps carrying the timing sensors comprise a single bearing cap providing bearing surfaces for each of the camshafts. The one journalled camshaft bearing surface of each of the camshafts are located at the same end of both of the camshafts. The journalled camshaft bearing surface of each camshaft is bounded by a pair of thrust flanges engaged with the common bearing cap for axially locating the camshafts. The timing sensors are mounted on the common bearing cap at the ends of respective elongated mounting plates and lie over the axis of rotation of the associated camshaft. The ends of the elongated plates spaced from the carried timing sensor are connected to the common bearing cap between the axes of rotation of the camshafts. The embodiment mentioned above provides an internal combustion engine comprising a cylinder head 2 and at least one camshaft 6,7 supported on a cylinder head 2 by a camshaft bearing means having at least one cam cap 17 and a cam angle sensor means for detecting rotation angle of said camshaft. Said cam angle sensor means comprises at least one cam angle sensor 24 attached to said cam cap 17. A variable valve timing device 9 is disposed at one end of said camshaft 6,7. Said cam angle sensor 24 is attached to the cam cap 17 being adjacent to said variable valve timing device 9. Said cam cap 17 comprises a camshaft bearing section and a sensor mounting section 23 which extends from said camshaft bearing section in longitudinal direction of the camshaft 6,7. Said cam angle sensor 24 is supported on said sensor mounting section 23. Said sensor mounting section 23 comprises a sensor inserting opening 28 receiving a sensor body 25 of said cam angle sensor 24. Said cam angle sensor 24 is provided with a mounting flange 26 secured on said sensor mounting section 23. Said cam angle sensor means comprises a cam angle detecting section (30) provided on said camshaft (6,7), wherein said cam angle sensor (24) is facing said cam angle detecting section (30), and a center axis said of said cam angle sensor (24) is crossing a center axis (C) of said camshaft (6,7). Said cylinder head 2 is provided with a head cover 12 which covers said camshaft 6,7, wherein said cam angle sensor 24 extends through said head cover 12. Said camshaft bearing means comprises a first bearing section 14 and a second bearing section 15 spaced from said first bearing section in longitudinal direction of the camshaft 6,7, wherein said cam angle sensor 24 is facing said camshaft 6,7 between said first and second bearing section 14, 15. Said camshaft 6,7 comprises a pair of thrust bearing flanges 48 axially supporting said camshaft 6,7 on the camshaft bearing means. Said cam cap 17 is provided with an oil passage means for supplying oil to said thrust bearing flanges 48. According to the embodiment, said engine comprising an intake camshaft 6 and an exhaust camshaft 7 supported on the cylinder head 2 of said engine. The cam angle sensor means comprises a first cam angle sensor 24 associated to the intake camshaft 6 and a second cam angle sensor 24 associated to the exhaust camshaft 7. Said cam angle sensors are attached to the cam cap 17 supporting the intake and exhaust camshaft 6,7 on a cylinder head 2. Said cam cap 17 comprises an intake camshaft bearing section and a first sensor mounting section 23 which extends from said intake camshaft bearing section in longitudinal direction of the intake camshaft 6, said first cam angle sensor 24 is supported on said first sensor mounting section 23. Said cam cap 17 further comprises an exhaust camshaft bearing section and a second sensor mounting section 23 which extends from said exhaust camshaft bearing section in longitudinal direction of the exhaust camshaft 7, said second cam angle sensor (24) is supported on said second sensor mounting section 23. Said intake camshaft bearing section and said exhaust camshaft bearing section are connected with each other to provide said cam cap 17 as a substantially integral member. The variable valve timing device WT 9 comprises a variable intake valve timing device VVT 10 disposed at one end of said intake camshaft (6), and variable exhaust valve timing device WT 11 disposed at one end of said exhaust camshaft (7) on the same cylinder head side as the intake valve timing device VVT 10. Said first and second cam angle sensor 24 is attached to the cam cap 17 being adjacent to said variable valve timing device VVT 10, 11. The cam angle sensor means comprises cam angle detecting sections 30 provided on each of said camshafts 6,7, respectively. Said cam angle sensors 24 are facing said cam angle detecting sections 30, and the center axes said of said cam angle sensors 24 are crossing the axial center axes C of said camshafts 6,7, respectively.

Claims: Internal combustion engine comprising a cylinder head (2) and at least one camshaft (6,7) supported on a cylinder head (2) by a camshaft bearing means comprising a first bearing section (14) having at least one cam bearing cap (17) and second bearing section (15) spaced from said first bearing section (14) in longitudinal direction of the camshaft (6,7), variable valve timing device (9) disposed at one end of said camshaft (6,7), and a cam angle sensor means for detecting a rotation angle of said camshaft, wherein said cam angle sensor means comprises at least one cam angle sensor (24) attached to said cam bearing cap (17), said cam angle sensor (24) is facing the camshaft (6,7), characterized in that said cam angle sensor (24) is attached to the cam bearing cap (17) being adjacent to said variable valve timing device (9), and said cam angle sensor (24) is facing said camshaft (6,7) between said first and second bearing sections (14, 15). Internal combustion engine according to claim 1, characterized in that said cam bearing cap (17) comprises a sensor mounting section (23) which extends from said first bearing section (14) in longitudinal direction of the camshaft (6,7), wherein said cam angle sensor (24) is supported on said sensor mounting section (23). Internal combustion engine according to claim 2, characterized In that said sensor mounting section (23) comprises a sensor inserting opening (28) receiving a sensor body (25) of said cam angle sensor (24), and said cam angle sensor (24) is provided with a mounting flange (26) secured on said sensor mounting section (23). Internal combustion engine according to at least one of the claims 1 to 3, characterized in that said cam angle sensor means comprises a cam angle detecting section (30) provided on said camshaft (6,7), wherein said cam angle sensor (24) is facing said cam angle detecting section (30), and a center axis of said cam angle sensor (24) is crossing a center axis (C) of said camshaft (6,7). Internal combustion engine according to at least one of the claims 1 to 4, characterized in that said cylinder head (2) is provided with a head cover (12) which covers said camshaft (6,7), wherein said cam angle sensor (24) extends through said head cover (12). Internal combustion engine according to at least one of the claims 1 to 5, characterized in that said camshaft (6,7) comprises a pair of thrust bearing flanges (48) axially supporting said camshaft (6,7) on the camshaft bearing means, wherein said cam bearing cap (17) is provided with an oil passage means for supplying oil to said thrust bearing flanges (48). Internal combustion engine according to at least one of the claims 1 to 6, characterized in that said engine comprising an intake camshaft (6) and an exhaust camshaft (7) supported on the cylinder head (2) of said engine and the cam angle sensor means comprises a first cam angle sensor (24) associated to the intake camshaft (6) and a second cam angle sensor (24) associated to the exhaust camshaft (7), wherein said cam angle sensors are attached to the cam bearing cap (17) supporting the intake and exhaust camshaft (6,7) on a cylinder head (2). Internal combustion engine according to claim 7, characterized in that said cam bearing cap (17) comprises an intake camshaft bearing section and a first sensor mounting section (23) which extends from said intake camshaft bearing section in longitudinal direction of the intake camshaft (6), said first cam angle sensor (24) is supported on said first sensor mounting section (23), and an exhaust camshaft bearing section and a second sensor mounting section (23) which extends from said exhaust camshaft bearing section in longitudinal direction of the exhaust camshaft (7), said second cam angle sensor (24) is supported on said second sensor mounting section (23), wherein said intake camshaft bearing section and said exhaust camshaft bearing section are connected with each other to provide said cam bearing cap (17) as a substantially integral member.

Inventors: UCHIDA MASAHIRO, UCHIDA, MASAHIRO, Uchida, Masahiro, c/o Yamaha Hatsudoki K.K.
Applicants: YAMAHA MOTOR CO LTD, YAMAHA HATSUDOKI KABUSHIKI KAISHA
Application year: 2001
Main classification: F01L1
IPC codes: F01L1, F02D35