internal combustion engine

Abstract

In an internal combustion engine, a cylinder head has an interior space. A camshaft is rotatably mounted to the cylinder head, and a pump drive cam is attached to the camshaft. A fuel pump is configured to be driven by the pump drive cam. A fuel pump mounting bracket attaches the fuel pump to the cylinder head, and a rotary angle measuring unit includes a measuring component attached to the camshaft and a rotary angle sensor attached to the cylinder head to measure the rotation angle of the measuring component. The cylinder head includes a partition that rotatably holds the camshaft. The partition divides the interior of the cylinder head into a cam chamber and a sensor chamber. The pump drive cam is located in the cam chamber, and the measuring component and rotary angle sensor are located in the sensor chamber.

Description

Technical area

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

[0002] Internal combustion engines for installation in vehicles, such as cars, include a sensor mounted on the cylinder head for measuring the rotation angle of a camshaft. An ignition coil is also mounted on the cylinder head to generate a high voltage to apply the high voltage to a spark plug, thereby igniting the spark plug. This ignition process of the spark plug can generate electromagnetic noise. For this reason, internal combustion engines are required that are designed to reduce the adverse effects of electromagnetic noise on the sensor.

[0003] For example, Japanese Patent Application Publication No. 2001-107773, hereinafter referred to as Patent Document 1, discloses such an internal combustion engine capable of reducing the adverse effects of electromagnetic noise on the sensor. The internal combustion engine disclosed in Patent Document 1 includes a camshaft, one end of which, referred to as the first end, extends outward from the cylinder head. A housing, i.e., a shroud, for a fuel pump is mounted on one side wall of the cylinder head that is closest to the first end of the camshaft among all the side walls of the cylinder head. The first end of the camshaft is disposed in the housing.

[0004] A pickup cam, which is a measuring component, and a pump cam are attached to the first end of the camshaft. The pump cam drives the fuel pump, and the rotational position of the pickup cam is configured to be measured by a cam angle sensor. The pump cam and the pickup cam are arranged in the housing. The cam angle sensor is arranged so that it is close to the pickup cam so that it can measure the rotational angle of the pickup cam.

[0005] The internal combustion engine is configured such that the cam angle sensor is mounted close to the pickup cam, which is attached to the first end of the camshaft. This allows the cam angle sensor to be positioned at a sufficient distance from the ignition coil located in the cylinder head. This arrangement reduces adverse effects on the cam angle sensor caused by electromagnetic noise generated by the ignition coil.

[0006] JP 2013-155692 A discloses an internal combustion engine comprising: a cylinder head having an internal space; a camshaft rotatably supported on the cylinder head; a pump drive cam; a fuel pump; a fuel pump mounting bracket configured to mount the fuel pump on the cylinder head; and a rotation angle measuring unit including a measuring component and a rotation angle sensor. The cylinder head includes a partition wall that divides the internal space of the cylinder head into a cam chamber housing the pump drive cam and a sensor chamber housing the measuring component and rotation angle sensor.

[0007] JP 2011-047 373 A discloses an internal combustion engine, wherein the cylinder head has a housing member mounted on a partition wall and configured such that an auxiliary device is drivably coupled to one end of a camshaft, the housing member mounting the auxiliary device on the partition wall. Brief descriptionTechnical problem

[0008] As described above, both the pump cam and the pickup cam of the internal combustion engine described above are arranged in the housing. The rotation of the pump cam causes a fuel pump plunger, which abuts against the pump cam, to reciprocate, and the reciprocating motion of the plunger causes the fuel pump to pump fuel. This configuration requires an oil supply to the contact surfaces of the pump cam and plunger to reduce friction between the contact surfaces of the pump cam and plunger.

[0009] Unfortunately, because the pump cam and pickup cam are both housed within the housing, the rotation of the pump cam can cause the supplied oil to splash toward the pickup cam, causing the splashed oil to adhere to the pickup cam. The oil adhering to the pickup cam can make it difficult for the cam angle sensor to accurately measure the rotation of the pickup cam, i.e., to accurately measure the camshaft rotation angle.

[0010] The present invention, which focuses on the problem described above, aims to provide internal combustion engines, each of which enables the rotation angle sensor to measure the rotation angle of a camshaft with high accuracy. Solution to the problem

[0011] The problem described above is solved by an internal combustion engine having the features of claim 1. A further development of the invention is defined in the dependent claim.

[0012] In the motor vehicle according to the invention, the sensor chamber housing the measuring component is isolated from the cam chamber housing the pump drive cam. This prevents lubricating oil, which lubricates the fuel pump and the pump drive cam, from entering the sensor chamber from the cam chamber. This therefore reliably prevents the rotation angle sensor from measuring oil, thereby enabling the rotation angle sensor to measure the rotation angle of the measuring component, i.e., the camshaft, with greater accuracy. Short description of the drawings Fig. 1 is a plan view of an internal combustion engine according to a present embodiment of the present invention; Fig. 2 is a plan view of a cylinder head of the internal combustion engine according to the present embodiment of the present invention, with the cylinder head cover removed from the cylinder head; Fig. 3 is a perspective view of the cylinder head of the internal combustion engine according to the present embodiment of the present invention, with the cylinder head cover removed from the cylinder head; Fig. 4 is a front view of the cylinder head of the internal combustion engine according to the present embodiment of the present invention, with the cylinder head cover removed from the cylinder head; Fig. 5 is a plan view of the cylinder head of the internal combustion engine according to the present embodiment of the present invention, with the cylinder head cover and a fuel pump mounting bracket removed from the cylinder head; Fig. 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. 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. 9 is a view schematically illustrating an intake drive mechanism of the internal combustion engine according to the present embodiment of the present invention; Fig. 10 is a side view of the cylinder head of the internal combustion engine according to the present embodiment of the present invention, with the cylinder head cover removed from the cylinder head; Fig. 11 is a side view of the cylinder head of the internal combustion engine according to the present embodiment of the present invention, with the cylinder head cover and the fuel pump mounting bracket removed from the cylinder head; Fig. 12 is a perspective view of the fuel pump mounting bracket of the internal combustion engine when the fuel pump mounting bracket is viewed from the left side of a vehicle according to the present embodiment of the present invention; and Fig. 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] Hereinafter, a present embodiment of internal combustion engines according to the present invention will be described with reference to the accompanying drawings.

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

[0015] The structure of the combustion engine 1 is first described below.

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

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

[0018] The cylinder head 11 is mounted on top of a cylinder block (not shown). The cylinder block contains, for example, four cylinders, each of which houses a piston (not shown) that is mounted to reciprocate. A crankshaft (not shown) is installed in the cylinder block, and the reciprocation of the piston is converted into rotation 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 width. The left side wall 33 extends in the longitudinal direction of the vehicle such that each extending end continues to one end, i.e., the left end, of a corresponding one of the rear side wall 31 and the front side wall 32. The right side wall 34 extends in the longitudinal direction of the vehicle such that each extending end continues to the other end, i.e., the right end, of a corresponding one of the rear side wall 31 and the front side wall 32. The bottom wall 35 has four edges, each of which continues to the lower end of a corresponding one of the rear, front, left, and right side walls 31, 32, 33, and 34 (see Fig. 3). That is, the cylinder head 11 is designed as a housing essentially in the shape of a rectangular parallelepiped.

[0021] Referring to the Fig. 2 and Fig. 3, four protrusions 16 are arranged at a substantially central portion of the top surface of the cylinder head 11 in the longitudinal direction of the vehicle. The four protrusions 16 are aligned along the vehicle width direction with regular spaces therebetween. Each of four spark plugs 15 is arranged in a corresponding one of the protrusions 16 such that its firing end protrudes into a combustion chamber (not shown) formed by a lower surface of the bottom wall 35 of the cylinder head 11 and the top surface of a corresponding one of the cylinders. That is, the engine 1 according to the present embodiment is configured as a gasoline direct injection four-cylinder engine provided with the four spark plugs 15.

[0022] Fig. 1 shows four ignition coils 2 mounted on 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. 3 illustrate an intake camshaft 13 and an exhaust camshaft 14 arranged on top of the cylinder head 11 so that they are parallel to each other. Fig. 2 and Fig. 8, each of the intake camshaft 13 and the exhaust camshaft 14 is rotatably supported by pairs of lower cam housings 18 and upper cam housings 17; each pair of the lower cam housing 18 and the 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 crankshaft sprocket (not shown), and the timing chain transmits rotation of the crankshaft to each of the intake and exhaust camshafts 13 and 14.

[0026] An intake port 46 is formed for each cylinder in the rear side wall 31 of the cylinder head 11, and an exhaust port (not shown) is also formed for each cylinder in the front side wall 32 of the cylinder head 11. The intake port 46 and the exhaust port communicate with 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 intake cam lobe 13A, that is, each intake cam protrusion 13A, has an eccentric disc shape such that a portion of the circumferential outer edge of the intake cam 13A protrudes. The outer edge of each intake cam lobe 13A bears on a rocker arm 19. One end of the rocker arm 19 is in contact with a pin 20A of a hydraulic shock adjusting member 20.

[0028] A roller 19A is held in the center of the rocker arm 19 by a pin 19B. The roller 19A protrudes from a top surface of the rocker arm 19 so that it is in contact with the intake 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 intake valve 21. The intake valve 21 is mounted in the cylinder head 11 so as to reciprocate in its axial direction. A valve spring 22, arranged around the stem of the intake valve 21, biases the intake valve 21 in the direction in which the intake valve 21 is lifted.

[0030] The protruding intake cam 13A, the rocker arm 19 and the intake valve 21 form an intake drive mechanism.

[0031] In particular, the preload force allows the valve head of the intake valve 21 to move toward 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 blocking the communication between the intake port 46 and the combustion chamber.

[0032] On the other hand, when the protruding portion of the outer edge of the rotating intake cam 13A contacts the roller 19A of the rocker arm 19, the protruding portion of the intake valve 21 causes the rocker arm 19 to push the intake valve 21 downward. This lifts the valve head of the intake valve 21 away from the intake port 46 against the biasing force of the valve spring 22. This results in the intake port 46 communicating with the combustion chamber. That is, reciprocating movements of the intake valve 21 due to rotation of the intake cam 13A allow the intake port 46 and the combustion chamber to communicate with each other or to be disconnected. 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 the circumferential outer edge of the exhaust cam 14A protrudes. The outer edge of each exhaust cam 14A abuts on a rocker arm (not shown), and the rocker arm is in contact with the top surface of the exhaust valve (not shown). That is, the exhaust drive mechanism composed of the exhaust cam 14A, the rocker arm (not shown), and the exhaust valve, which has the same configuration as the intake drive mechanism, enables rotation of the exhaust cam 14A to cause the exhaust valve to open or close the exhaust port in the same manner as the intake drive mechanism. This allows the exhaust port and the combustion chamber to communicate with each other or to be cut off from each other.

[0034] Referring to the Fig. 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 coupled to the fuel pump 41 so that a connection can be established. Low-pressure fuel is supplied to the fuel pump 41 via the fuel supply line 44.

[0035] In addition, 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 adjusted by the fuel pump 41.

[0036] Referring to Fig. 1, a feed line 45 is attached to the cylinder head 11, which is coupled to the fuel supply line 43 in such a way that a connection can be established. The feed line 45 supplies the fuel introduced by the fuel supply line 43 to fuel injectors (not shown).

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

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

[0039] Referring to the Fig. 3 and Fig. 4, an exhaust gas collection passage 47 is formed in the front side wall 32; the exhaust gas collection passage 47 collects exhaust gases discharged from the respective cylinders via the corresponding exhaust ports. A catalyst unit (not shown) communicates with the exhaust gas collection passage 47 and purifies the exhaust gas collected by the exhaust gas collection passage 47, so that the purified 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 is made of, for example, a respective metallic material, and the cylinder head cover 12 is made of, for example, 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. As shown in Fig. 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 Fig. 8). The connector 55 electrically connects the electromagnetic valve 53 to a control unit (not shown).

[0042] 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 communicates with 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 includes a cylinder 51e and a flange 51f. The piston 52 is installed in the cylinder 51e so as to be movable. The flange 51f enables the pump body 51 to be attached to the fuel pump mounting bracket 42.

[0043] The inlet passage 51a is coupled to the fuel supply line 44, and the outlet passage 51b is coupled to the fuel supply line 43. A check valve (not shown) provided on the outlet passage 516 opens when the pressure of the fuel contained in the compression chamber 51c exceeds a predetermined value. This causes fuel to be discharged from the outlet passage 51b into the fuel supply line 43.

[0044] The piston 52 includes a roller 52a that abuts the pump drive cam 13B, and a lifter member 52b that rotatably supports the roller 52a. The lifter member 52b is pressed toward the pump drive cam 13B by the spring 54, so that the roller 52a abuts the pump drive cam 13B with a predetermined pressing force. The piston 52 reciprocates in a direction perpendicular to the axial direction of the intake camshaft 13 as the pump drive cam 13B rotates.

[0045] Rotation of the pump drive cam 13B causes the piston 52 to move downward, thereby opening the intake passage 51a, resulting in fuel being drawn into the compression chamber 51c at a higher volume. Conversely, rotation of the pump drive cam 13B causes the piston 52 to move upward, thereby closing the intake passage 51a, resulting in an increase in the pressure of the fuel drawn into the compression chamber 51c.

[0046] The electromagnetic valve 53 includes a solenoid that is controllable 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.

[0047] As in Fig. As shown in Fig. 9, a portion of the intake cam 13A is disposed between the intake camshaft 13 and the plunger 52 of the fuel pump 41. This results in the direction of a load F1 applied by the valve spring 22 from the rocker arm 19 to the intake camshaft 13 being opposite to the direction of a load F2 applied by the spring 54 from the plunger 52 to the intake camshaft 13.

[0048] Referring to the Fig. 7 and Fig. 8, the intake camshaft 13 of the present embodiment has a left end portion 13a extending outward from the left side wall 33 of the cylinder head 11, to which the intake cams 13A, the pump drive cam 13B, and the exhaust cam 14A are attached.

[0049] 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 lobe. The left end portion 13a of the intake camshaft 13 serves, for example, as an end portion of the camshaft of the present invention.

[0050] A pickup rotor 61, which is an example of measuring elements, is mounted on the left end portion 13a of the intake camshaft 13; the left end portion 13a extends outward from the left side wall 33. On the outer circumference of the pickup rotor 61, a plurality of spaced projections 61A are formed in the circumferential direction; at least some of the projections 61A have different lengths, ie, heights, in the corresponding radial directions of the pickup rotor 61 (see the Fig. 10 and Fig. 11). On the left side wall 33, a cam angle sensor 62 is mounted via a housing component 81, which will be described later, in such a way that the cam angle sensor 62 is arranged so that it is opposite to the pickup rotor 61 (see the Fig. 10 and Fig. 11). The cam angle sensor 62 functions to measure the rotation angle of the pickup rotor 61. The pickup rotor 61 of the present embodiment serves, for example, as a measuring component of the present invention, and the cam angle sensor 62 serves, for example, as a rotation angle sensor of the present invention. The pickup rotor 61 and the cam angle sensor 62 serve, for example, as a rotation angle measuring unit according to the present invention.

[0051] 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; the position is opposite the left side wall 33. The intake camshaft 13 is rotatably supported by the left side wall 33 and the fuel pump mounting bracket 42 via the bearing 13b.

[0052] 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. 13. The first side wall 71 extends in the axial direction of the intake camshaft 13 so as to be mounted on an 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 so as to be mounted on the upper surface of the left side wall 33. The connecting wall 73 connects the first and second side walls 71 and 72.

[0053] A bearing holder 72a is formed at a predetermined position of the second side wall 72, on which the bearing 13b is mounted. The bearing holder 72a has a substantially semicircular concave shape from the lower end of the second side wall 72 to hold the bearing 13b of the intake camshaft 13 from above. A bearing holder 33A is formed at a predetermined position of the left side wall 33, on which the bearing 13b is mounted. The bearing holder 33A has a substantially semicircular concave shape from the upper side of the left side wall 33 to hold 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.

[0054] The fuel pump mounting bracket 42 further includes a fuel pump mounting projection 74. The fuel pump mounting projection 74 is integrally formed with a front side portion, i.e., an inner side portion, of the first side wall 71, a right side portion, i.e., an inner side portion, 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.

[0055] A through hole 74a, into 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 upper opening end of the through hole 74a is exposed to the outside.

[0056] The fuel pump mounting projection 74 also has a flange 74b formed around the peripheral wall of the opening of the through hole 74a on the top 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 with screws 76A (see Fig. 8).

[0057] The flange 74b is inclined at a predetermined angle with respect to the top of each of the rear side wall 31, the front side wall 32, and the left side wall 33, that is, with respect to the top of the cylinder head 11. This allows inclination of the longitudinal direction, that is, the axial direction of the piston 52, of the fuel pump 41 mounted in the fuel pump mounting bracket 42, with respect to the top of the cylinder head 11. This results in inclination of 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 a decrease in the vertical height of the engine 1, thereby enabling a decrease in the vertical height of the vehicle.

[0058] Referring to the Fig. 12 and Fig. 13, on the outer portion of the first side wall 71, a fastening projection 75A is formed, which protrudes outward and has an axial direction extending substantially in the vertical direction. A through-hole 75a is formed through the fastening projection 75A along the axial direction of the fastening projection 75A. Furthermore, on an outer portion of one end of the second side wall 72, a fastening projection 75B is formed, which protrudes outward and has an axial direction extending substantially in the vertical direction; the end continues to the first side wall 71. 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, which are arranged to align with the corresponding through holes 75a and 75b, respectively. 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.

[0059] On an outer portion of the second side wall 72, separate from its end, a fastening projection 75C is formed, which protrudes outward and has an axial direction extending substantially in the vertical direction. 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 to align with the corresponding through hole 75c; the screw hole 33B is located on the opposite side of the intake camshaft 13 from the screw hole 31B, so as to be away from the screw hole 31B.

[0060] This causes the bolt 76C inserted into the bolt hole 31B to be located on the intake camshaft 13 side opposite that of the bolt 76D inserted into the bolt hole 33B, so that it is away from the bolt hole 31B. The bolt 76D inserted through the through hole 75c of the second side wall 72 of the fuel pump mounting bracket 42 is fixed in the bolt hole 33B, so that the fuel pump mounting bracket 42 is immovably fitted to the left side wall 33. The bolts 76B, 76C, and 76D serve, for example, as fastening members of the present invention.

[0061] 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 a part of the bracket 42, lies above the bearing holder 33A when viewed from above the cylinder head 11 (see Fig. 7). This results in the fuel pump 41 being mounted on the fuel pump mounting bracket 42, while the fuel pump 41 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.

[0062] As in the Fig. 12 and Fig. 13, the fuel pump mounting bracket 42 further includes a mounting portion 78 that protrudes further upward relative to the top of the second side wall 72. A through hole 78a in the form of a threaded hole is formed in the horizontal direction through the upper end of the mounting portion 78. The mounting portion 78 allows the housing component 81, which will be described later, to be mounted thereto. In addition, Fig. 1 shows that the second side wall 72 of the present embodiment is arranged between the leftmost ignition coil 2 and the cam angle sensor 62.

[0063] Referring to the Fig. 1, Fig. 2, Fig. 4, Fig. 6 and Fig. 7, the cylinder head 11 includes the housing member 81. A vacuum pump 82 is mounted on the second side wall 72 of the fuel pump mounting bracket 42 and the left side wall 33 by means of the housing member 81. In other words, the housing member 81 of the cylinder head 11 according to the present embodiment is arranged between the vacuum pump 82 and the set of the second side wall 72 and the left side wall 33.

[0064] Referring to the Fig. 3 and Fig. 10, the housing member 81 includes 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 periphery 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 periphery 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 periphery of the annular housing body 81a.

[0065] For example, referring to the Fig. 1 and Fig. 2, the vacuum pump 82 includes a pump body, for example, having a cylindrical shape, and a mounting member 82a surrounding at least the outer periphery of the pump body. The mounting member 82a is attached to the housing body 81a.

[0066] The left end portion 13a of the intake camshaft 13 and the pickup rotor 61 are located in the housing body 81a. The tip of the left end portion 13a of the intake camshaft 13 is coupled to the vacuum pump 82. Rotation of the intake camshaft 13 drives the vacuum pump 82, so that the vacuum pump 82 generates a negative pressure and provides the negative pressure, for example, to a brake booster.

[0067] An inner hollow sensor housing 81e penetrates the outer peripheral portion 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.

[0068] A through-hole 81b1 is formed through the first flange 81b in alignment with the through-hole 78a of the fastening portion 78 of the second side wall 72. Inserting a screw 76E into the through-hole 81b1 of the housing component 81 and the through-hole 78a of the second side wall 72 results in the housing component 81, together with the vacuum pump 82, being fastened to the second side wall 72 (see Fig. 6).

[0069] In a similar manner, 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 results in the housing component 81 being fixed together with the vacuum pump 82 to the left side wall 33 (see Fig. 6).

[0070] In addition, a through hole 81d1 is formed through the third flange 81d. Inserting a screw 76E2 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 results in the housing component 81 being fixed together with the vacuum pump 82 to the left side wall 33 (see Fig. 6).

[0071] A housing 81f extends forward and downward from the outer periphery portion 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).

[0072] Referring to the Fig. 7 and Fig. 8, the pickup 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, ie, its interior, into a cam chamber 63 in which the pump drive cam 13B is housed, and a sensor chamber 64 in which the pickup rotor 61 and the cam angle sensor 62 are housed.

[0073] The left side wall 33 of the present embodiment serves, for example, as a partition wall and a side wall of the present embodiment, and the vacuum pump 82 serves, for example, as an auxiliary device of the present invention.

[0074] Note that an unillustrated coolant passage and an unillustrated thermostat are provided in the interior of a lower portion of the housing member 81; the lower portion abuts the left side wall 33. Coolant flowing through an unillustrated water jacket formed inside the cylinder head 11 is discharged into the coolant passage.

[0075] The coolant passage is separated from the sensor chamber 64; the sensor chamber 64 is defined as an upper space of the housing component 81 in which the pickup rotor 61 and the cam angle sensor 62 are housed. This prevents the coolant from flowing into the sensor chamber 64.

[0076] Referring to the Fig. 1 and Fig. 2, the screw 76C is arranged so that it extends in the axial direction of the intake camshaft 13 from the bearing holder 33A of the left side wall 33 (see Fig. 5). The bolt 76C is attached to the cylinder head 11 while overlying the housing member 81 in a direction passing through the bolt 76C and perpendicular to the axial direction of the intake camshaft 13.

[0077] In other words, the screw hole 31B into which the screw 76C is inserted is formed in the cylinder head 11 while being located above the housing member 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.

[0078] Referring to Fig. 7, the pump drive cam 13B is adjacent to the left side wall 33 in the cam chamber 63, and the pickup rotor 61 is adjacent to the left side wall 33 in the sensor chamber 64. That is, the pump drive cam 13B and the pickup 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 pickup rotor 61. The left side wall 33 and the second side wall 72 of the fuel pump mounting bracket 42 rotatably support the intake camshaft 13 via the bearing 13b.

[0079] For example, referring to Fig.11, the cam angle sensor 62 mounted on the housing member 81 includes a body 62A mounted on the sensor housing 81e of the housing member 81, and a sensor element 62B. The body 62A includes a coupler coupled between the sensor element 62B and a control unit (not shown) for connection. The sensor element 62B protrudes from the body 62A toward the pickup rotor 61 so as to oppose the pickup rotor 61 in a radial direction of the pickup rotor 61; this configuration of the sensor element 62B enables the sensor element 62B to detect rotation of the pickup rotor 61. The sensor element 62B of the present embodiment serves, for example, as a sensor component of the present invention.

[0080] The cam angle sensor 62 is mounted on the sensor housing 81e of the housing component 81 such that the direction B in which the sensor element 62B protrudes from the body 62A is substantially perpendicular to both: (1) the axial direction of the intake camshaft 13 (2) the direction of movement A, ie the longitudinal direction, of the piston 52.

[0081] In other words, the cam angle sensor 62 is mounted on the sensor housing 81e of the housing member 81 such that the direction B, which is substantially perpendicular to a sensor surface 62C of the sensor element 62B facing the outer periphery of the pickup rotor 61, is substantially perpendicular to both: (1) the axial direction of the intake camshaft 13 (2) the direction of movement A, ie the longitudinal direction, of the piston 52.

[0082] 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, and the roller 52a of the piston 52 and the pump drive cam 13B.

[0083] For example, from a main oil gallery, unillustrated oil passages are formed through the individual intake and exhaust 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 locations, via the individual oil passages.

[0084] Next, the operation of the engine 1 constructed above will be described below.

[0085] The pickup rotor 61 is mounted on the left end portion 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.

[0086] A measurement signal indicating the rotation angle of the intake camshaft 13 is output from the pickup rotor 61 to the control unit (not shown). Based on the measurement signal, the control unit calculates, for example, the rotational speed of the intake camshaft 13 per unit time and the rotational position of the intake camshaft 13.

[0087] The ignition coil 2 generates a high voltage to apply the high voltage to the spark plug 15, thereby igniting the spark plug 15. The ignition process of the spark plug 15 may cause the generation of electromagnetic noise, and the electromagnetic noise may adversely affect the cam angle sensor 62. Thus, there is a need to reduce the adverse effects on the cam angle sensor 62 due to electromagnetic noise.

[0088] 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 rotatably supports the intake camshaft 13 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 pickup rotor 61 and the cam angle sensor 62 are housed.

[0089] 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.

[0090] The engine 1 of the present embodiment is configured such that oil is supplied to the interface between the pump drive cam 13B and the roller 52a of the piston 52. This lubricates the interface between the pump drive cam 13B and the roller 52a. After lubricating the interface between the pump drive cam 13B and the roller 52a, the oil splashes around the interface.

[0091] As described above, the cylinder head 11 of the present embodiment includes the left side wall 33 which 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 pickup rotor 61 and the cam angle sensor 62 are housed.

[0092] This allows the sensor chamber 64, which houses the cam angle sensor 62, to be isolated from the cam chamber 63, which houses the pump drive cam 13B. Therefore, this prevents oil that lubricates the roller 52a and the pump drive cam 13B and that is splashed from the roller 52a and the pump drive cam 13B from entering the sensor chamber 64 from the cam chamber 63.

[0093] This reliably prevents the cam angle sensor 62 from measuring oil, allowing the cam angle sensor 62 to measure the rotation angle of the intake camshaft 13 with greater accuracy. This results in a higher measurement accuracy of the rotation angle of the intake camshaft 13.

[0094] The fuel pump 41 of the present embodiment is configured to pump fuel pressurized by the pump drive cam 13B based on the reciprocating movements of the piston 52. This configuration may cause the pump drive cam 13B to be subjected to a reaction force from the fuel pump 41, so that the intake camshaft 13 may be subjected to a torsional moment and / or a bending load.

[0095] From this point of view, the engine 1 of the present embodiment is configured such that the left side wall 33 of the cylinder head 11 serves as a partition wall. The partition wall serves to dispose the cam chamber 63 in a first housing of the cylinder head 11 and to dispose the sensor chamber 64 in a second housing of the cylinder head 11 on the outside of the first housing. That is, the cylinder head 11 includes the first housing formed by the side walls 31 to 34 and the bottom wall 35, and the second housing formed by the housing member 81 and the left side wall 33.

[0096] In addition to this configuration, engine 1 is configured such that (1) the left side wall 33 rotatably supports the left end portion 13a of the intake camshaft 13, the left end portion 13a extending outwardly from the left side wall 33 into the sensor chamber 64, (2) the pump drive cam 13B is disposed adjacent to the left side wall 33 in the cam chamber 63 and the pickup rotor 61 is disposed adjacent to the left side wall 33 in the sensor chamber 64.

[0097] These configurations allow the pump drive cam 13B to be disposed inside the cylinder head 11 with respect to the left side wall 33 and the pickup rotor 61 to be attached to the left end portion 13a of the intake camshaft 13, with the left end portion 13a being disposed outside the left side wall 33.

[0098] This feature further increases the rigidity of the intake camshaft 13 even when the intake camshaft 13 is subjected to the reaction force from the fuel pump 41 to be subjected to a torsional moment and / or a bending load while the fuel pump 41 is driven due to the rotation of the pump drive cam 13B, as compared with the following comparative example: the pump drive cam 13B and the pickup rotor 61 are attached to the left end portion 13a of the intake camshaft 13, the left end portion 13a being arranged outside the left side wall 33.

[0099] This prevents the left end portion 13a of the intake camshaft 13, which is located outside the left side wall 33, from vibrating, thereby enabling the cam angle sensor 62 to reliably measure the rotational speed of the pickup rotor 61.

[0100] In addition, the engine 1 of the present embodiment includes the fuel pump mounting bracket 42 that mounts the fuel pump 41 to the cylinder head 11. The fuel pump mounting bracket 42 includes the first side wall 71, the second side wall 72, and the connecting wall 73. The first side wall 71 extends in the axial direction of the intake camshaft 13 so as to be attached to the top of the rear side wall 31. The second side wall 72 extends from the first side wall 71 along the left side wall 33 so as to be attached to the top of the left side wall 33. The connecting wall 73 connects the first and second side walls 71 and 72.

[0101] This increases the rigidity of the left side wall 33 through the fuel pump mounting bracket attached to the left side wall 33, thereby efficiently increasing the rigidity of the intake camshaft 13. Therefore, this more effectively prevents the left end portion 13a of the intake camshaft 13, which is located outside the left side wall 33, from vibrating.

[0102] The engine 1 of the present embodiment further includes the housing member 81 and the vacuum pump 82 configured to be driven by the intake camshaft 13. The housing member 81 is disposed between the vacuum pump 82 and the left side wall 33 and second side wall 72 assembly. The housing member 81 allows the vacuum pump 82 to be integrated with the left side wall 33 and the second side wall 72 and is drivably connected to the left end portion 13a of the intake camshaft 13. The housing member 81 also houses the pickup rotor 61, and the cam angle sensor 62 is mounted on the housing member 81 so as to oppose the pickup rotor 61.

[0103] The housing member 81, which allows the left side wall 33 and the second side wall 72 to integrally support the vacuum pump 82, further increases the rigidity of the left side wall 33, thereby efficiently increasing the rigidity of the intake camshaft 13. Therefore, this more effectively prevents the left end portion 13a of the intake camshaft 13, which is mounted outside the left side wall 33, from vibrating.

[0104] The housing component 81, which conventionally includes a thermostat, houses the pickup rotor 61 and the cam angle sensor 62. This eliminates the need to provide a new space in which the pickup rotor 61 and the cam angle sensor 62 are arranged in the engine 1. This results in a compact size of the engine 1.

[0105] Moreover, the engine 1 of the present embodiment is configured such that the second side wall 72 of the fuel pump mounting bracket 42 is located between the set of ignition coils 2 and the cam angle sensor 62.

[0106] 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 electromagnetic noise generated by the ignition coils 2 during the ignition processes of the spark plugs 15. This allows the cam angle sensor 62 to measure the rotation angle of the intake camshaft 13 with greater accuracy.

[0107] Specifically, each of the cylinder head 11 and the fuel pump mounting bracket 42 is made of a corresponding metallic material, and 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.

[0108] 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 metal cylinder head cover. Therefore, even when the metal cylinder head 11 and the support 42 are used, the weight of the engine 1 is reduced by reducing the weight of the plastic cylinder head cover 12, thereby increasing the effects of shielding the cam angle sensor 62 from electromagnetic noise. List of reference symbols 1 engine (combustion engine) 2 ignition coil 11 Cylinder head 12 cylinder head covers 13 Intake camshaft (camshaft) 13B Pump drive cam 13a left end section 15 Spark plug 31 rear side wall 32 front side panel 33 left side wall (partition wall or side wall) 34 right side wall 41 Fuel pump 42 Fuel pump mounting bracket 51c compression chamber 52 pistons A Direction of movement of the piston 61 Sensor rotor (measuring component) 62 Cam angle sensor (rotation angle sensor) 62A Cam angle sensor body (rotation angle sensor) 62B Sensor element of the cam angle sensor (rotation angle sensor) B Direction in which the sensor element protrudes from the body 63 Cam chamber 64 sensor chamber 71 first side wall 72 second side wall 73 Connecting wall 81 Housing component 81a annular housing body of the housing component 81b first flange of the housing component 81c second flange of the housing component 81e Sensor housing of the housing component 82 Vacuum pump (auxiliary device).

Claims

[1] Internal combustion engine (1) which is a transversely mounted four-stroke engine for a vehicle, comprising: a cylinder head (11) having an interior space; Spark plugs (15); a camshaft (13) rotatably supported on the cylinder head (11); a pump drive cam (13B) mounted on the camshaft (13); a fuel pump (41) configured to be driven by the pump drive cam (13B); a fuel pump mounting bracket (42) configured to mount the fuel pump (41) to the cylinder head (11); and a rotation angle measuring unit having a measuring component (61) mounted on the camshaft (13) and a rotation angle sensor (62) mounted on the cylinder head (11) for measuring a rotation angle of the measuring component (61), wherein the cylinder head (11) comprises 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), wherein the rear side wall (31) and the front side wall (32) are opposite each other and extend in the direction of the vehicle width, wherein the left side wall (33) extends in the longitudinal direction of the vehicle such that each extending end continues to an end of a corresponding one of the rear side wall (31) and the front side wall (32), wherein the right side wall (34) extends in the longitudinal direction of the vehicle such thatthat each extending end continues to the other end of a corresponding one of the rear side wall (31) and the front side wall (32), wherein the bottom wall (35) has four edges, each of which continues to the lower end of a corresponding one of the rear, front, left and right side walls (31, 32, 33, 34), wherein the cylinder head (11) is designed as a housing in the shape of a rectangular parallelepiped;, wherein the left side wall (33) serves as a partition wall that rotatably supports the camshaft (13); wherein the partition wall divides the interior of the cylinder head (11) into a cam chamber (63) and a sensor chamber (64), wherein the pump drive cam (13B) is accommodated in the cam chamber (63), wherein the measuring component (61) and the rotation angle sensor (62) are accommodated in the sensor chamber (64); characterized by , that the fuel pump mounting bracket (42) comprises: a first side wall (71) extending in an axial direction of the camshaft (13) so as to be mounted on an upper surface of the rear side wall (31), a second side wall (72) extending from the first side wall (71) along the left side wall (33) so as to be mounted on an upper surface of the left side wall (33), and a connecting wall (73) connecting the first and second side walls (71, 72); a vacuum pump (82) is mounted by means of a housing member (81) on the second side wall (72) of the fuel pump mounting bracket (42) and the left side wall (33), wherein the tip of an end portion (13a) of the camshaft (13) is coupled to the vacuum pump (82); the rotation angle sensor (62) includes a body (62A) attached to a sensor housing (81e) of the housing component (81), and a sensor element (62B), wherein the sensor element (62B) protrudes from the body (62A) toward the measuring component (61) in a direction (B) that is perpendicular to both the axial direction of the camshaft (13) and a direction (A) in which a piston (52) of the fuel pump (41) reciprocates; and the second side wall (72) is arranged between ignition coils (2) attached to the cylinder head (11) and the rotation angle sensor (62). [2] Internal combustion engine (1) according to claim 1, characterized by , that: the housing component (81) further comprises: a substantially annular housing body (81a) in which the end of the camshaft (13) and the measuring component (61) are arranged; a first flange (81b) extending upward from an upper surface of an outer periphery of the annular housing body (81a) so as to be fixed to the second side wall (72) of the fuel pump mounting bracket (42); and a second flange (81c) extending along an outer surface of the left side wall (33) so as to be fixed to the left side wall (33).

Images