internal combustion engine

Abstract

In an internal combustion engine, a camshaft includes a pump drive cam and a rotor and is rotatably mounted on a cylinder head. A fuel pump is attached to the cylinder head and includes a piston. The piston is configured to move in a direction substantially perpendicular to the axial direction of the camshaft as the pump drive cam rotates. A sensor includes a mounting unit attached to the cylinder head and a sensor unit. The sensor unit, for measuring the rotor's angle of rotation, projects from the mounting unit in a direction substantially perpendicular to the axial direction of the camshaft and substantially perpendicular to the piston's direction of movement toward the rotor.

Description

Technical field

[0001] The present invention relates to internal combustion engines and, more specifically, to internal combustion engines equipped with a sensor to detect the rotation angle of a camshaft. State of the art

[0002] In the cylinder head of an internal combustion engine, a camshaft with a cam lobe is provided to drive an intake or exhaust valve; the internal combustion engine is installed in vehicles, such as motor vehicles. A sensor is provided near the camshaft to measure the angle of rotation of a rotor mounted on the camshaft, thereby measuring the camshaft's rotation angle.

[0003] A pump drive cam is also mounted on the camshaft. The pump drive cam causes a piston of a fuel pump to move when the camshaft rotates, thereby causing the fuel pump to deliver fuel under high pressure. Such an internal combustion engine, equipped with the cylinder head configured above, is disclosed, for example, in publication JP 2008-223 609 A.

[0004] Publication JP 2013-155 692 A discloses a fuel pump for an internal combustion engine with a housing comprising a sensor housing and a pump housing. The sensor housing contains a sensor and a sensor rotor. The sensor rotor is mounted on a camshaft of the internal combustion engine, and the sensor measures the rotation of the sensor rotor.

[0005] Documents US 2013 / 0133598A1 and JP 2013-113107A each show a structure for attaching an auxiliary device, such as a fuel injection pump, to a cylinder head of an internal combustion engine. An extension of the internal combustion engine's camshaft extends into a housing chamber of the auxiliary device and has a cam for actuating a piston of the auxiliary device.

[0006] Publication JP 2011-47 373 A discloses an auxiliary device, driven by the camshaft of an internal combustion engine and, for example, a vacuum pump, wherein the rotation angle of the camshaft is detected by means of a sensor rotor. The sensor rotor comprises an annular section on which a tooth-shaped section with a plurality of teeth is provided. Brief description of the technical problem

[0007] The pump drive cam mounted on the camshaft may be subject to a reaction force from the fuel pump, which delivers fuel under high pressure, so that the camshaft may be subject to a torsional moment and / or a bending load along the direction of movement of the fuel pump piston.

[0008] This can cause the camshaft to vibrate in the direction in which the reaction force is applied to the camshaft, i.e., along the direction of piston movement, so that the distance between the rotor mounted on the camshaft and the sensor fluctuates in the direction of vibration, i.e., the direction of piston movement. This can degrade the measurement accuracy of the camshaft rotation angle.

[0009] The present invention, which focuses on the above problem, aims to provide internal combustion engines, each of which prevents the measurement accuracy of the rotation angle of a camshaft from deteriorating. Solution to the problem

[0010] An internal combustion engine according to one aspect of the present invention comprises a cylinder head and a camshaft, the latter including a pump drive cam, a rotor, and a bearing, the camshaft being rotatably mounted on the cylinder head. The internal combustion engine includes a fuel pump mounted on the cylinder head, which includes a piston. The piston is configured to move in a direction perpendicular to an axial direction of the camshaft when the pump drive cam rotates. The internal combustion engine includes a sensor, which includes a mounting unit attached to the cylinder head. The sensor includes a sensor unit,to measure a rotation angle of the rotor. The sensor unit projects from the mounting unit in a direction perpendicular to the axial direction of the camshaft and perpendicular to the direction of movement of the piston towards the rotor. The internal combustion engine further includes a fuel pump mounting bracket attached to the cylinder head and configured to mount the fuel pump to the cylinder head, and a cylinder head cover which includes an ignition coil for firing a spark plug and is attached to the cylinder head to cover the cylinder head and the fuel pump mounting bracket, the cylinder head comprising a side wall for partitioning between a cam chamber and a sensor chamber, the cam chamber accommodating the pump drive cam, the sensor chamber accommodating the rotor and the sensor, and the camshaft having one end,extending outwards from the side wall of the cylinder head, the rotor being mounted on the end of the camshaft, the side wall of the cylinder head and a side wall of the fuel pump mounting bracket rotatably holding the camshaft bearing, the side wall of the fuel pump mounting bracket being attached to a top surface of the side wall of the cylinder head, the rotor being located adjacent to the side wall of the cylinder head in the axial direction of the camshaft, and the side wall of the fuel pump mounting bracket being located between the ignition coil and the sensor. Advantageous effects of the invention

[0011] The internal combustion engine according to the aspect of the present invention is configured such that the sensor unit projects out of the mounting unit in a direction substantially perpendicular to the axial direction of the camshaft and substantially perpendicular to the direction of movement of the piston towards the rotor.

[0012] Even though the pump drive cam is subjected to a reaction force from the fuel pump piston, causing the camshaft to vibrate in a direction perpendicular to the axial direction of the intake camshaft and along the piston's direction of movement, the internal combustion engine's configuration reduces the degree of camshaft bending or twisting in the direction in which the sensor unit protrudes. This, in turn, reduces fluctuations in the distance between the rotor and the sensor unit in the opposite direction between the rotor's outer circumference and the sensor surface. This prevents a deterioration in the camshaft rotation angle measurement accuracy. Brief description of the drawings Fig. Figure 1 is a top view of an internal combustion engine according to a present embodiment of the present invention; Fig. Figure 2 is a top view of a cylinder head of the internal combustion engine according to the present embodiment of the present invention, wherein the cylinder head cover has been removed from the cylinder head; Fig. Figure 3 is a perspective view of the cylinder head of the internal combustion engine according to the present embodiment of the present invention, wherein the cylinder head cover has been removed from the cylinder head; Fig. Figure 4 is a front view of the cylinder head of the internal combustion engine according to the present embodiment of the present invention, wherein the cylinder head cover has been removed from the cylinder head; Fig. Figure 5 is a top view of the cylinder head of the internal combustion engine according to the present embodiment of the present invention, wherein the cylinder head cover and a fuel pump mounting bracket have been removed from the cylinder head; Fig. Figure 6 is a side view of the internal combustion engine according to the present embodiment of the present invention; Fig. 7 is a cross-sectional view along a line VII-VII of Fig. 6 according to the present embodiment of the present invention; Fig. Figure 8 is a perspective view of the main components of the cylinder head, from which the cylinder head cover has been removed, according to the present embodiment of the present invention; Fig. Figure 9 is a view schematically representing an intake drive mechanism of the internal combustion engine according to the present embodiment of the present invention; Fig. Figure 10 is a side view of the cylinder head of the internal combustion engine according to the present embodiment of the present invention, wherein the cylinder head cover has been removed from the cylinder head; Fig. Figure 11 is a side view of the cylinder head of the internal combustion engine according to the present embodiment of the present invention, wherein the cylinder head cover and the fuel pump mounting bracket have been removed from the cylinder head; Fig. Figure 12 is a perspective view of the fuel pump mounting bracket of the internal combustion engine when viewing the fuel pump mounting bracket from the left side of a vehicle according to the present embodiment of the present invention; and Fig. Figure 13 is a perspective view of the fuel pump mounting bracket of the internal combustion engine when viewing the fuel pump mounting bracket from the front of the vehicle according to the present embodiment of the present invention. Description of an embodiment

[0013] In the following, an embodiment of internal combustion engines according to the present invention is described with reference to the accompanying drawings.

[0014] Fig. Figures 1 to 13 represent an internal combustion engine 1 according to the present embodiment.

[0015] The following section describes the structure of the internal combustion engine 1.

[0016] Referring to Fig. In the case of the internal combustion engine 1, which is referred to as an engine 1, a transversely mounted four-stroke engine which, during two back-and-forth movements of a piston (not shown) in each of the cylinders, performs a series of four strokes, which include an intake stroke, a compression stroke, a power stroke and an exhaust stroke.

[0017] For example, engine 1 is installed in a vehicle. Engine 1 includes a cylinder head 11 and a cylinder head cover 12. When viewed from the perspective of a driver sitting in the driver's seat of the vehicle, the longitudinal direction (i.e., the direction from front to back), the right-to-left direction (i.e., the direction of the vehicle's width), and the vertical direction (i.e., the direction from top to bottom) are represented in the drawings by corresponding arrows.

[0018] The cylinder head 11 is mounted on top of a cylinder block (not shown). The cylinder block contains, for example, four cylinders, each with a piston (not shown) installed in such a way that it moves back and forth. A crankshaft (not shown) is installed in the cylinder block, and the reciprocating motion of the piston is converted into a rotary motion of the crankshaft.

[0019] Referring to the Fig. 1 and Fig. 2 the cylinder head 11 includes a rear side wall 31, a front side wall 32, a left side wall 33, a right side wall 34 and a bottom wall 35.

[0020] The rear side wall 31 and the front side wall 32 are opposite each other and extend in the direction of the vehicle's width. The left side wall 33 extends longitudinally along the vehicle such that each extending end continues to one end, i.e., the left end, corresponding to the rear side wall 31 and the front side wall 32. The right side wall 34 extends longitudinally along the vehicle such that each extending end continues to the other end, i.e., the right end, corresponding to the rear side wall 31 and the front side wall 32. The bottom wall 35 has four edges, each extending to the lower end of a corresponding rear, front, left, and right side wall 31, 32, 33, and 34, respectively (see Fig. 3) That is, the cylinder head 11 is designed as a housing essentially in the shape of a right-angled parallelepiped.

[0021] Referring to the Fig. 2 and Fig. 3 Four projections 16 are arranged on a section of the upper surface of the cylinder head 11 that is substantially central in the longitudinal direction of the vehicle. The four projections 16 are aligned along the direction of the vehicle's width with regular intervals between them. Each of the four spark plugs 15 is arranged in a corresponding projection 16 such that its ignition end projects into a combustion chamber (not shown) formed by a lower surface of the bottom wall 35 of the cylinder head 11 and the upper surface of a corresponding cylinder. That is to say, the engine 1 according to the present embodiment is designed as a gasoline direct-injection four-cylinder engine equipped with the four spark plugs 15.

[0022] Fig. Figure 1 represents four ignition coils 2, which are attached to the cylinder head 11, corresponding one-to-one to the spark plugs 15. Each ignition coil 2 ignites the corresponding spark plug 15.

[0023] Fig. 2 and Fig. Figure 3 represents an intake camshaft 13 and an exhaust camshaft 14, which are arranged on top of the cylinder head 11 such that they are parallel to each other. Referring to the Fig. 2 and Fig. 8 each of the intake camshaft 13 and the exhaust camshaft 14 is rotatably held by pairs of lower cam housings 18 and upper cam housings 17; each pair of lower cam housing 18 and upper cam housing 17 serves as a bearing.

[0024] A cam gear (not shown) is mounted on the right end of the intake camshaft 13, and a cam gear (not shown) is mounted on the right end of the exhaust camshaft 14. A timing chain (not shown) is suspended from the cam gears.

[0025] The timing chain is also suspended on a crank gear (not shown) of the crankshaft, and the timing chain transmits a rotation of the crankshaft to each of the intake and exhaust camshafts 13 and 14.

[0026] In the rear side wall 31 of the cylinder head 11, an intake port 46 is formed for each cylinder, and in the front side wall 32 of the cylinder head 11, an exhaust port (not shown) is formed for each cylinder. The intake port 46 and the exhaust port are connected to the combustion chamber of the corresponding cylinder.

[0027] A plurality of intake cams 13A are mounted on the intake camshaft 13. Referring to Fig. 9 Each inlet cam 13A, i.e., each inlet cam projection 13A, has an eccentric disk shape such that a portion of the circumferential outer edge of the inlet cam 13A protrudes. The outer edge of each inlet cam 13A rests on a rocker arm 19. One end of the rocker arm 19 is in contact with a pin 20A of a hydraulic shock adjusting element 20.

[0028] A roller 19A is held in the center of the lever arm 19 by means of a pin 19B. The roller 19A protrudes from the top of the rocker arm 19 in such a way that it is in contact with the inlet cam 13A.

[0029] A lower surface of the other end 19D, i.e., the lever end 19D, of the rocker arm 19 is in contact with the upper end, i.e., the stem end, of the inlet valve 21. The inlet valve 21 is mounted in the cylinder head 11 so as to be movable back and forth in its axial direction. A valve spring 22, arranged around the stem of the inlet valve 21, biases the inlet valve 21 in the direction in which the inlet valve 21 is lifted.

[0030] The foreground inlet cam 13A, rocker arm 19 and inlet valve 21 form an inlet drive mechanism.

[0031] In particular, the preload force enables the valve head of the intake valve 21 to move towards the intake port 46 when the circular outer edge of the rotating intake cam 13A is in contact with the roller 19A of the rocker arm 19. This closes the intake port 46, thereby sealing off the connections between the intake port 46 and the combustion chamber.

[0032] On the other hand, the protruding section of the intake cam 13A causes the rocker arm 19 to push the intake valve 21 downwards when the protruding section of the outer edge of the rotating intake cam 13A is in contact with the roller 19A of the rocker arm 19. This lifts the valve head of the intake valve 21 away from the intake port 46 against the preload force of the valve spring 22. This results in the intake port 46 coming into contact with the combustion chamber. That is, reciprocating movements of the intake valve 21 based on a rotation of the intake cam 13A allow the intake port 46 and the combustion chamber to come into contact or be broken. The rocker arm 19 and the valve spring 22 serve, for example, as a valve lifter of the present invention.

[0033] A plurality of exhaust cams 14A are mounted on the exhaust camshaft 14. Each exhaust cam 14A has a disc shape, and a portion of its circumferential outer edge protrudes. The outer edge of each exhaust cam 14A rests against a rocker arm (not shown), and the rocker arm is in contact with the top of the exhaust valve (not shown). That is, the exhaust actuation mechanism, consisting of the exhaust cam 14A, the rocker arm (not shown), and the exhaust valve, and having the same configuration as the intake actuation mechanism, allows the exhaust cam 14A to rotate in the same way as the intake actuation mechanism, causing the exhaust valve to open or close the exhaust port. This allows the exhaust port and the combustion chamber to communicate or be separated.

[0034] Referring to the Fig. At points 1 to 4 and 6 to 10, a fuel pump 41 is mounted on the cylinder head 11 via a fuel pump mounting bracket 42. A fuel supply line 44 is connected to the fuel pump 41 in such a way that a connection can be established. Fuel at low pressure is supplied to the fuel pump 41 via the fuel supply line 44.

[0035] Furthermore, a fuel supply line 43 is coupled to the fuel pump 41 in such a way that a connection can be established. Fuel is introduced into the fuel supply line 43, the pressure of which is regulated by the fuel pump 41.

[0036] Referring to Fig. A delivery line 45 is attached to the cylinder head 11 and is coupled to the fuel supply line 43 in such a way that a connection can be established. The delivery line 45 supplies fuel to the fuel injectors (not shown), which is supplied by the fuel supply line 43.

[0037] Each fuel injector is provided for a corresponding combustion chamber in the cylinder head 11. Specifically, the delivery line 45 distributes high-pressure fuel, supplied by the fuel supply line 43, to the individual fuel injectors. Each fuel injector sprays high-pressure fuel, distributed by the delivery line 45, directly into the corresponding combustion chamber.

[0038] Referring to Fig. 1 is an inlet manifold (not shown) attached to the rear side wall 31; the inlet manifold distributes intake air, which has been cleaned by means of an air filter (not shown), into the individual intake channels 46.

[0039] Referring to the Fig. 3 and Fig. In the front side wall 32, an exhaust gas collection passage 47 is formed; the exhaust gas collection passage 47 collects exhaust gases that are discharged from the respective cylinders via the corresponding exhaust ports. A catalyst unit (not shown), which is connected to the exhaust gas collection passage 47, cleans the exhaust gas collected by the exhaust gas collection passage 47, so that the cleaned exhaust gas is discharged via an exhaust pipe (not shown). A turbine housing of a turbocharger (not shown) may be provided between the catalyst unit and the exhaust gas collection passage 47.

[0040] Each of the cylinder head 11 and the fuel pump mounting bracket 42, for example, consists of a corresponding metallic material, and the cylinder head cover 12, for example, consists of a resin material.

[0041] Referring to the Fig. 4, Fig. 7 and Fig. 8 a pump drive cam 13B is mounted on the intake camshaft 13; the pump drive cam 13B drives the fuel pump 41.

[0042] As in Fig. As shown in Figure 7, the fuel pump 41 consists of a pump body 51, a piston 52, an electromagnetic valve 53, a spring 54 and a connector 55 (see Figure 7). Fig. 8). The connector 55 electrically connects the electromagnetic valve 53 to a control unit not shown.

[0043] The pump body 51 includes an inlet port 51a, an outlet port 51b, a compression chamber 51c, and an on / off valve 51d. The inlet port 51a draws in fuel, and the outlet port 51b discharges fuel. The compression chamber 51c is connected to both the inlet port 51a and the outlet port 51b. The electromagnetic valve 53 causes the on / off valve 51d to open or close the inlet port 51a. The pump body 51 also consists of a cylinder 51e and a flange 51f. The piston 52 is mounted in the cylinder 51e in such a way that it is movable. The flange 51f allows the pump body 51 to be attached to the fuel pump mounting bracket 42.

[0044] The inlet port 51a is connected to the fuel supply line 44, and the outlet port 51b is connected to the fuel supply line 43. A check valve (not shown) provided at the outlet port 516 opens when the pressure of the fuel contained in the combustion chamber 51c exceeds a predetermined value. This causes fuel to be discharged from the outlet port 51b into the fuel supply line 43.

[0045] The piston 52 includes a roller 52a, which rests on the pump drive cam 13B, and a lifting element 52b, which allows the roller 52a to rotate. The lifting element 52b is pressed towards the pump drive cam 13B by the spring 54, so that the roller 52a rests on the pump drive cam 13B with a predetermined contact force. The piston 52 moves back and forth in a direction perpendicular to the axial direction of the inlet camshaft 13 when the pump drive cam 13B rotates.

[0046] A rotation of the pump drive cam 13B causes the piston 52 to move downwards, thereby opening the intake port 51a, which results in fuel being drawn into the compression chamber 51c at a higher volume. Conversely, a rotation of the pump drive cam 13B causes the piston 52 to move upwards, thereby closing the intake port 51a, which results in an increase in the pressure of the fuel drawn into the compression chamber 51c.

[0047] The electromagnetic valve 53 contains a solenoid that can be controlled by the control unit. The electromagnetic valve 53 opens the on / off valve 51d when fuel is drawn in from the intake port 51a and closes the on / off valve 51d when the fuel pressure increases.

[0048] As in Fig. As shown in Figure 9, part of the intake cam 13A is arranged between the intake camshaft 13 and the piston 52 of the fuel pump 41. This results in the direction of a load F1 exerted on the intake camshaft 13 by the valve spring 22 from the rocker arm 19 being opposite to the direction of a load F2 exerted on the intake camshaft 13 by the spring 54 from the piston 52.

[0049] Referring to the Fig. 7 and Fig. 8 The inlet camshaft 13 of the present embodiment has a left end section 13a which extends outwards from the left side wall 33 of the cylinder head 11, to which the inlet cams 13A, the pump drive cam 13B and the exhaust cam 14A are attached.

[0050] The intake camshaft 13 of the present embodiment serves, for example, as a camshaft of the present invention, and at least one of the intake cams 13A serves, for example, as a cam projection. The left end section 13a of the intake camshaft 13 serves, for example, as an end section of the camshaft of the present invention.

[0051] A sensor rotor 61, which is an example of measuring elements, is mounted on the left end section 13a of the intake camshaft 13; the left end section 13a extends outwards from the left side wall 33. A plurality of spaced-apart projections 61A are formed on the outer circumference of the sensor rotor 61 in the circumferential direction; at least some of the projections 61A have different lengths, i.e., heights in the corresponding radial directions of the sensor rotor 61 (see the Fig. 10 and Fig. 11) A cam angle sensor 62 is attached to the left side wall 33 via a housing component 81, which will be described later, such that the cam angle sensor 62 is positioned opposite the sensor rotor 61 (see the Fig. 10 and Fig. 11) The cam angle sensor 62 functions by measuring the rotation angle of the sensor rotor 61. The sensor rotor 61 of the present embodiment serves, for example, as a measuring element of the present invention, and the cam angle sensor 62 serves, for example, as a rotor of the present invention. The cam angle sensor 62 serves, for example, as a sensor according to the present invention.

[0052] Referring to the Fig. 5 and Fig. 7 A bearing 13b is mounted at a position on the left side of the intake camshaft 13; this position is opposite the left side wall 33. The intake camshaft 13 is rotatably held by the left side wall 33 and the fuel pump mounting bracket 42 via the bearing 13b.

[0053] In particular, the fuel pump mounting bracket 42 includes a first side wall 71, a second side wall 72 and a connecting wall 73, as shown in the Fig. 12 and Fig. Figure 13 shows the first side wall 71 extending in the axial direction of the intake camshaft 13 such that it is mounted on the upper surface of the rear side wall 31. The second side wall 72 extends from the first side wall 71 along the left side wall 33 such that it is mounted on the upper surface of the left side wall 33. The connecting wall 73 joins the first and second side walls 71 and 72.

[0054] A bearing holder 72a is formed at a predetermined position on the second side wall 72, on which the bearing 13b is mounted. The bearing holder 72a has a substantially semicircular concave shape extending from the lower end of the second side wall 72 to support the bearing 13b of the intake camshaft 13 from above. A bearing holder 33A is formed at a predetermined position on the left side wall 33, on which the bearing 13b is mounted. The bearing holder 33A has a substantially semicircular concave shape extending from the upper surface of the left side wall 33 to support the bearing 13b of the intake camshaft 13 from below (see the Fig. 5 and Fig. 7) That is, the bearing holders 33A and 72a serve, for example, as a bearing holder according to the present invention.

[0055] The fuel pump mounting carrier 42 also includes a fuel pump mounting projection 74. The fuel pump mounting projection 74 is integrally formed with a section on the front, i.e., an inner section, of the first side wall 71, a section on the right side, i.e., an inner section, of the second side wall 72, and an inner part of the connecting wall 73. The axial direction of the fuel pump mounting projection 74 extends obliquely upward and rearward from the inner side of the first and second side walls 71 and 72.

[0056] A through-hole 74a, in which the pump body 51 of the fuel pump 41 is inserted, is formed through the fuel pump mounting projection 74. The through-hole 74a extends in the axial direction of the fuel pump mounting projection 74 such that an end of the through-hole 74a opening at the top is exposed to the outside.

[0057] The fuel pump mounting projection 74 also has a flange 74b formed around the circumferential wall of the opening of the through-hole 74a on its upper side. The flange 51f of the pump body 51 is fixedly mounted on the flange 74b of the fuel pump mounting projection 74, while the pump body 51 of the fuel pump 41 is inserted into the through-hole 74a by screws 76A (see Fig. 8).

[0058] The flange 74b is inclined at a predetermined angle with respect to the upper surface of each of the rear side wall 31, the front side wall 32, and the left side wall 33, i.e., with respect to the upper surface of the cylinder head 11. This allows for an inclination in the longitudinal direction, i.e., the axial direction of the piston 52, of the fuel pump 41, which is mounted in the fuel pump mounting bracket 42, with respect to the upper surface of the cylinder head 11. This results in an inclination in the longitudinal direction of the fuel pump 41 with respect to the vertical direction of the engine 1. The angle between the flange 74b and the upper surface of the cylinder head 11 can be set to be within a range of 0 degrees to 180 degrees. This allows for a reduction in the vertical height of the engine 1, thereby reducing the vertical height of the vehicle.

[0059] Referring to the Fig. 12 and Fig. 13. A fastening projection 75A is formed on the outer section of the first side wall 71, projecting outwards and having an axial direction extending substantially vertically. A through-hole 75a is formed through the fastening projection 75A along the axial direction of the fastening projection 75A. Furthermore, a fastening projection 75B is formed on an outer section of one end of the second side wall 72, projecting outwards and having an axial direction extending substantially vertically; the end continues to the first side wall 75A. A through-hole 75b is formed through the fastening projection 75B along the axial direction of the fastening projection 75B. Screws 76B and 76C are inserted through the respective through-holes 75a and 75b. Referring to Fig. 5. Screw holes 31A and 31B are formed in the rear side wall 31, arranged so that they are aligned with the corresponding through holes 75a and 75b. The screws 76B and 76C, which are inserted through the respective through holes 75a and 75b of the first side wall 71 of the fuel pump mounting bracket 42, are secured in the respective screw holes 31A and 31B, so that the fuel pump mounting bracket 42 is immovably attached to the rear side wall 31.

[0060] On an outer section of the second side wall 72, a fastening projection 75C is formed separately from its end. This projection extends outwards and has an axial direction that is substantially vertical. A through-hole 75c is formed through the fastening projection 75C along the axial direction of the fastening projection 75C. A screw 76D is inserted through the through-hole 75c. Referring to Fig. 5 a screw hole 33B is formed in the left side wall 33, which is arranged so that it is aligned with the corresponding through hole 75c; the screw hole 33B is located on the side of the intake camshaft 13 opposite the screw hole 31B, so that it is away from the screw hole 31B.

[0061] This causes screw 76C, which is inserted in screw hole 31B, to be located on the side of the intake camshaft 13 opposite to that of screw 76D, which is inserted in screw hole 33B, so that it is away from screw hole 31B. Screw 76D, which is inserted through the through-hole 75c of the second side wall 72 of the fuel pump mounting bracket 42, is secured in screw hole 33B, so that the fuel pump mounting bracket 42 is immovably mounted on the left side wall 33. Screws 76B, 76C, and 76D serve, for example, as fastening elements of the present invention.

[0062] Referring to the Fig. 1, Fig. 2 and Fig. 8 the fuel pump mounting bracket 42 is attached to the cylinder head 11, while the second side wall 72, which is part of the bracket 42, lies above the bearing holder 33A when viewed from above the cylinder head 11 (see Fig. 7).

[0063] This results in the fuel pump 41 being attached to the fuel pump mounting bracket 42, while the fuel pump is located above the upper end of the left side wall 33 when the fuel pump 41 is viewed from above the cylinder head 11.

[0064] As in the Fig. 12 and Fig. As shown in Figure 13, the fuel pump mounting bracket 15 further includes a mounting section 78 that projects further upwards with respect to the top of the second side wall 72. A threaded bore 78a is formed horizontally through the upper end of the mounting section 78a. The mounting section 78 allows the housing component 81, which will be described later, to be attached to it. Furthermore, Fig. Figure 1 shows that the second side wall 72 of the present embodiment is arranged between the ignition coil 2 located furthest to the left and the cam angle sensor 62.

[0065] Referring to the Fig. 1, Fig. 2, Fig. 4, Fig. 6 and Fig. The cylinder head 11 includes the housing component 81. A vacuum pump 82 is attached to the second side wall 72 of the fuel pump mounting bracket 42 and the left side wall 33 by means of the housing component 81. In other words, the housing component 81 of the cylinder head 11 is arranged between the vacuum pump 82 and the assembly consisting of the second side wall 72 and the left side wall 33, according to the present embodiment.

[0066] Referring to the Fig. 3 and Fig. The housing component 81 comprises a housing body 81a, a first flange 81b, a second flange 81c, and a third flange 81d. The housing body 81a has a substantially annular shape, and the first flange 81b extends upward from the upper end of the outer circumference of the annular housing body 81a. The second flange 81c extends forward along the outer surface of the left side wall 33 from the front portion of the outer circumference of the annular housing body 81a. The third flange 81d extends downward along the outer surface of the left side wall 33 from the lower end of the outer circumference of the annular housing body 81a.

[0067] For example, with regard to the Fig. 1 and Fig. 2 The vacuum pump 82 comprises a pump body, which, for example, has a cylindrical shape, and a mounting element 82a, which surrounds at least the outer circumference of the pump body. The mounting element 82a is attached to the housing body 81a.

[0068] The left end section 13a of the intake camshaft 13 and the pickup rotor 61 are located in the housing body 81a. The tip of the left end section 13a of the intake camshaft 13 is coupled to the vacuum pump 82. Rotation of the intake camshaft 13 drives the vacuum pump 82, causing it to generate a vacuum and supplying it, for example, to a brake booster.

[0069] An inner hollow sensor housing 81e penetrates the section of the outer circumference of the housing body 81a between the first and second flanges 81b and 81c. The cam angle sensor 62 is installed in the sensor housing 81e.

[0070] A through-hole 81b 1 is formed through the first flange 81b in alignment with the through-hole 78a of the mounting section 78 of the second side wall 72. If a screw 76E is inserted into the through-hole 81b1 of the housing component 81 and the through-hole 78a of the second side wall 72, this fastens the housing component 81 together with the vacuum pump 82 to the second side wall 72 (see Fig. 6).

[0071] Similarly, a through-hole 81c1 is formed through the second flange 81c. If a screw 76E1 is inserted into the through-hole 81c1 of the housing component 81 so that it is screwed into the left side wall 33 of the cylinder head 11, this fastens the housing component 81 together with the vacuum pump 82 to the left side wall 33 (see Fig. 6).

[0072] Furthermore, a through-hole 81d1 is formed through the third flange 81d. If a screw 76E2 is inserted into the through-hole 81d1 of the housing component 81 so that it is screwed into the left side wall 33 of the cylinder head 11, this fastens the housing component 81 together with the vacuum pump 82 to the left side wall 33 (see Fig. 6).

[0073] A housing 81f extends forward and downward from the section of the outer circumference of the housing body 81a between the second and third flanges 81c and 81d. Referring to the Fig. 4 and Fig. 6 the housing 81f is attached to the left side wall 33 of the cylinder head 11 with screws 76F (see Fig. 8).

[0074] Referring to the Fig. 7 and Fig. 8 The sensor rotor 61 is housed in the housing component 81. That is, the cylinder head 11 is configured such that the left side wall 33 and the second side wall 72 divide the cylinder head 11, i.e. its interior, into a cam chamber 63, in which the pump drive cam 13B is housed, and a sensor chamber 64, in which the sensor rotor 61 and the cam angle sensor 62 are housed.

[0075] The left side wall 33 of the present embodiment serves, for example, as a partition and a side wall of the present embodiment, and the vacuum pump 82 serves, for example, as an auxiliary device of the present invention.

[0076] It should be noted that a coolant passage (not shown) and a thermostat (not shown) are provided in the interior of a lower section of the housing component 81; the lower section rests against the left side wall 33. Coolant flowing through a water jacket (not shown) formed inside the cylinder head 11 is drained into the coolant passage.

[0077] The coolant passage is separated from the sensor chamber 64; the sensor chamber 64 is defined as an upper chamber of the housing component 81, in which the sensor rotor 61 and the cam angle sensor 62 are housed. This prevents the coolant from flowing into the sensor chamber 64.

[0078] Referring to the Fig. 1 and Fig. 2 the screw 76C is arranged such that it is in the axial direction of the intake camshaft 13 from the bearing holder 33A of the left side wall 33 (see Fig. 5) is separated. The screw 76C is attached to the cylinder head 11, while it lies above the housing component 81 in a direction passing through the screw 76C and perpendicular to the axial direction of the intake camshaft 13.

[0079] In other words, the screw hole 31B, into which the screw 76C is inserted, is formed in the cylinder head 11, while it lies above the housing component 81 in a direction passing through the screw hole 31B and perpendicular to the axial direction of the intake camshaft 13, as shown in Fig. 5 shown.

[0080] Referring to Fig. The pump drive cam 13B is adjacent to the left side wall 33 in the cam chamber 63, and the sensor rotor 61 is adjacent to the left side wall 33 in the sensor chamber 64. That is, the pump drive cam 13B and the sensor rotor 61 are arranged such that the left side wall 33, the second side wall 72, and the bearing 13b are located between the pump drive cam 13B and the sensor rotor 61. The left side wall 33 and the second side wall 72 of the fuel pump mounting bracket 42 rotatably hold the bearing 13b.

[0081] For example, with reference to Fig. The cam angle sensor 62, which is attached to the housing component 81, comprises a mounting unit 62A, which is attached to the sensor housing 81e of the housing component 81, and a sensor element 62B. The mounting unit 62A includes a coupler that is coupled between the sensor element 62B and a control unit (not shown) such that a connection can be established. The sensor element 62B projects from the mounting unit 62A in the direction of the sensor rotor 61 such that it is radially opposite the sensor rotor 61; this configuration of the sensor element 62B enables it to detect a rotation of the sensor rotor 61. The sensor element 62B of the present embodiment serves, for example, as a sensor unit of the present invention.

[0082] The cam angle sensor 62 is attached to the sensor housing 81e of the housing component 81 such that the direction B in which the sensor element 62B protrudes from the mounting unit 62A is essentially perpendicular to both: (1) the axial direction of the intake camshaft 13 (2) the direction of movement A, i.e. the longitudinal direction, of piston 52.

[0083] In other words, the cam angle sensor 62 is attached to the sensor housing 81e of the housing component 81 such that the direction B, which is essentially perpendicular to a sensor surface 62C of the sensor element 62B that is opposite the outer circumference of the sensor rotor 61, is essentially perpendicular to both: (1) the axial direction of the intake camshaft 13 (2) the direction of movement A, i.e. the longitudinal direction, of piston 52.

[0084] In the cam chamber 63 of the cylinder head 11, lubricating oil is supplied to the interfaces between each intake cam 13A and the corresponding rocker arm, each exhaust cam 14A and the corresponding rocker arm, as well as to the roller 52a of the piston 52 and the pump drive cam 13B.

[0085] Oil passages (not shown) are formed from a main oil channel through the individual inlet and outlet cams 13A and 14A in the cylinder head 11. Oil is supplied to the contact surfaces of the roller 52a of the piston 52 and the pump drive cam 13B, and other points, via the individual oil passages.

[0086] The following section describes how the motor 1 constructed above works.

[0087] The sensor rotor 61 is mounted on the left end section 13a of the intake camshaft 13, and the cam angle sensor 62 measures the projections 61A of the rotor 61 when the intake camshaft 13 is rotated.

[0088] A measurement signal indicating the rotation angle of the intake camshaft 13 is output by the sensor rotor 61 to the control unit (not shown). Based on this measurement signal, the control unit calculates, for example, the rotational speed of the intake camshaft 13 per unit of time and its rotational position.

[0089] Ignition coil 2 generates a high voltage to apply to spark plug 15, thereby igniting it. The ignition process of spark plug 15 can generate electromagnetic noise, which can adversely affect camshaft angle sensor 62. Therefore, there is a need to reduce the adverse effects of electromagnetic noise on camshaft angle sensor 62.

[0090] In view of such a requirement, the cylinder head 11 of the engine 1 according to the present embodiment includes the left side wall 33. The left side wall 33 holds the intake camshaft 13 rotatably and divides the interior of the cylinder head 11 into the cam chamber 63, in which the pump drive cam 13B is housed, and the sensor chamber 64, in which the receiver rotor 61 and the cam angle sensor 62 are housed.

[0091] This allows the left side wall 33 to spatially separate the ignition coils 2 from the cam angle sensor 62, thereby reducing adverse effects on the cam angle sensor 62 due to the electromagnetic noise generated by the ignition coils 2.

[0092] The cam angle sensor 62 of the engine 1 according to the present embodiment is attached to the sensor housing 81e of the housing component 81 of the cylinder head 11 such that the direction B in which the sensor element 62B projects from the mounting unit 62A is essentially perpendicular to both: (1) the axial direction of the intake camshaft 13 (2) the direction of movement A, i.e. the longitudinal direction, of piston 52.

[0093] In other words, the cam angle sensor 62 of the motor 1 according to the present embodiment is attached to the sensor housing 81e of the housing component 81 such that the direction B, which is substantially perpendicular to a sensor surface 62C of the sensor element 62B that is opposite the outer circumference of the sensor rotor 61, is substantially perpendicular to both: (1) the axial direction of the intake camshaft 13 (2) the direction of movement A, i.e. the longitudinal direction, of piston 52.

[0094] When the pump drive cam 13B is subjected to a reaction force from the piston 52 of the fuel pump 41, causing the intake camshaft 13 to vibrate along a direction perpendicular to its axial direction (for example, along the direction of movement of the piston 52), the configuration of the engine 1 reduces the degree of bending or twisting of the intake camshaft 13 in the direction in which the sensor element 62B protrudes. This, therefore, reduces fluctuations in the distance between the sensor rotor 61 and the sensor element 62B in the opposite direction between the outer circumference of the sensor rotor 61 and the sensor surface of the sensor element 62B. This prevents a deterioration in the measurement accuracy of the rotation angle of the intake camshaft 13.

[0095] The left side wall 33 of the cylinder head 11 according to the present embodiment includes the bearing holder 33A, which rotatably holds the bearing 13b mounted on the intake camshaft 13. The pump drive cam 13B and the pickup rotor 61 are arranged such that the bearing 13b, which is mounted on the intake camshaft 13, is sandwiched between them in the axial direction of the intake camshaft 13 (see Fig. 7).

[0096] This configuration allows the pump drive cam 13B and the pickup rotor 61 to be located close to the bearing 13b, which is mounted on the intake camshaft 13. This reduces the torque acting on the left end section 13a of the intake camshaft 13, where the pickup rotor 61 is mounted, even when a reaction force based on the piston 51 of the fuel pump 41 is applied to the pump drive cam 13B, causing the intake camshaft 13 to vibrate along the direction of movement of the piston 52.

[0097] This therefore enables a more efficient reduction of the extent of bending or twisting of the intake camshaft 13 in the direction in which the sensor element 62B protrudes. This, in turn, more efficiently reduces fluctuations in the distance between the sensor rotor 61 and the sensor element 62B in the opposite direction between the outer circumference of the sensor rotor 61 and the sensor surface of the sensor element 62B. This more efficiently prevents a deterioration in the measurement accuracy of the rotation angle of the intake camshaft 13.

[0098] The engine 1 according to the present embodiment includes the fuel pump mounting bracket 42, which mounts the fuel pump 41 to the cylinder head 11, and the cylinder head cover 12, to which the ignition coils 2 are mounted. The cylinder head cover 12 is attached to the cylinder head 11 to cover the cylinder head 11 and the fuel pump mounting bracket 42. The left end section 13a extends outwards from the left side wall 33 into the sensor chamber 64. The pickup rotor 61 is mounted on the left end section 13a of the intake camshaft 13. The fuel pump mounting bracket 42 and the left side wall 33 rotatably support the bearing 13b of the intake camshaft 13, and the pickup rotor 31 is located in the axial direction of the intake camshaft 13 close to the left side wall 33.

[0099] The left side wall 33 of the cylinder head 11, as configured above, blocks the lubricating oil that lubricates the piston 52 of the fuel pump 41 and the pump drive cam 13B, thus preventing the lubricating oil from splashing onto the pickup rotor 61. This reliably prevents the sensor element 62B of the cam angle sensor 62 from detecting oil, allowing the sensor element 62B to measure the rotation angle of the pickup rotor 61. This results in a more accurate measurement of the rotation angle of the intake camshaft 13.

[0100] The left side wall 33 of the cylinder head 11 blocks the sensor element 62B from the set of ignition coils 2. This causes the left side wall 33 to block electromagnetic noise generated by the ignition coils 2 during the ignition processes of the spark plugs, thus enabling the sensor element 62B to measure the rotation angle of the intake camshaft 13 with greater accuracy.

[0101] Furthermore, the engine 1 of the present embodiment is configured such that the second side wall 72 of the fuel pump mounting carrier 42 is located between the set of ignition coils 2 and the cam angle sensor 62.

[0102] This causes both the left side wall 33 and the second side wall 72 of the fuel pump mounting bracket 42 to block electromagnetic noise, thereby reducing adverse effects on the cam angle sensor 62 due to the electromagnetic noise generated by the ignition coils 2 during the spark plug ignition processes. This allows the cam angle sensor 62 to measure the rotation angle of the intake camshaft 13 with greater accuracy.

[0103] In particular, each of the cylinder head 11 and the fuel pump mounting bracket 42 is made of a corresponding metallic material, and the cylinder head cover 12 is made of a resin material.

[0104] The left side wall 33 of the cylinder head 11 and the second side wall 72 of the fuel pump mounting bracket 42 separate the cam angle sensor 62 from the ignition coils 2. This allows the left side wall 33 and the second side wall 72 to block electromagnetic noise more efficiently.

[0105] The cylinder head cover 12 of the present embodiment is made of a resin material. This reduces the weight of the cylinder head cover 12 compared to the weight of a metallic cylinder head cover. Therefore, this reduces the weight of the engine 1 by reducing the weight of the plastic cylinder head cover 12, even when the metallic cylinder head 11 and the carrier 42 are used to enhance the shielding effect of the cam angle sensor 62 from electromagnetic noise.

[0106] The present embodiment of the present invention has been disclosed. It is obvious that a person skilled in the art can modify the present embodiment without departing from the scope of the present invention. All modified and equivalent aspects are to be included in the following claims. Reference symbol list 1 Engine (internal combustion engine) 2 Ignition coil 11 Cylinder head 12 Cylinder head covers 13 Intake camshaft (camshaft) 13B Pump drive cam 13a left end section (end section of the camshaft) 15 Spark plug 33 left side wall (side wall) 41 Fuel pump 42 Fuel pump mounting brackets 52 pistons 61 Pickup rotor (rotor) 62 Camshaft angle sensor (sensor) 62A Mounting Unit 62B Sensor Unit

Claims

[1] Internal combustion engine (1) comprising: a cylinder head (11); a camshaft (13) comprising a pump drive cam (13B), a rotor (61) and a bearing (13b), wherein the camshaft (13) is rotatably held on the cylinder head (11); a fuel pump (41) attached to the cylinder head (11) and comprising a piston (52), wherein the piston (52) is configured to move in a direction perpendicular to an axial direction of the camshaft (13) when the pump drive cam (13B) rotates; a sensor (62) comprising a mounting unit (62A) attached to the cylinder head (11) and a sensor unit (62B) for measuring a rotation angle of the rotor (61), wherein the sensor unit (62B) projects out of the mounting unit (62A) in a direction perpendicular to the axial direction of the camshaft (13) and perpendicular to the direction of movement of the piston (52) towards the rotor (61); a fuel pump mounting bracket (42) attached to the cylinder head (11) and configured to mount the fuel pump (41) to the cylinder head (11); and a cylinder head cover (12) which includes an ignition coil (2) for igniting a spark plug (15) and is attached to the cylinder head (11) to cover the cylinder head (11) and the fuel pump mounting bracket (42), wherein the cylinder head (11) comprises a side wall (33) for dividing between a cam chamber (63) and a sensor chamber (64), wherein the cam chamber (63) accommodates the pump drive cam (13B), wherein the sensor chamber (64) accommodates the rotor (61) and the sensor (62), wherein the camshaft (13) has an end (13a) which extends outwards from the side wall (33) of the cylinder head (11), wherein the rotor (61) is mounted on the end (13a) of the camshaft (13), wherein the side wall (33) of the cylinder head (11) and a side wall (72) of the fuel pump mounting bracket (42) rotatably hold the bearing (13b) of the camshaft (13), wherein the side wall (72) of the fuel pump mounting bracket (42) is attached to a top side of the side wall (33) of the cylinder head (11), wherein the rotor (61) is located in the axial direction of the camshaft (13) adjacent to the side wall (33) of the cylinder head (11) and wherein the side wall (72) of the fuel pump mounting bracket (42) is located between the ignition coil (2) and the sensor (62). [2] Internal combustion engine (1) according to claim 1, wherein: the pump drive cam (13B) and the rotor (61) are arranged such that the bearing (13b) of the camshaft (13) is arranged between them in the axial direction of the camshaft (13). [3] Internal combustion engine (1) according to claim 1 or 2, wherein each of the cylinder head (11) and the fuel pump mounting carrier (42) is made of a corresponding metallic material and the cylinder head cover (12) is made of a plastic material.

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