Oil passage structure of internal combustion engine

Abstract

To provide oil passage structure of an internal combustion engine, enabling quick operation of an intake-side valve timing adjustment device after starting the internal combustion engine, thereby enabling reduction of exhaust gas and reduction of fuel consumption.SOLUTION: In the oil passage structure of an engine 1, a main oil passage 62 and an exhaust-side head oil passage 64 extend upward from under an exhaust-side in-cam-cap oil passage 66 to the exhaust-side in-cam-cap oil passage 66, and an intake-side head oil passage 63 has: a first intake-side head oil passage 63A extending from the main oil passage 62 to an intake-side wall 4B of a cylinder head 4; and a second intake-side head oil passage 63B extending upward from an outer end 63a in the extending direction, of the first intake-side head oil passage 63A and reaching an intake-side in-cam-cap oil passage 65. In the second intake-side head oil passage 63B, a boss 69 for sensor mounting is provided to which a hydraulic sensor 70 is mounted.SELECTED DRAWING: Figure 7

Description

[Technical Field]

[0001] The present invention relates to an oil passage structure for an internal combustion engine. [Background technology]

[0002] Conventionally, variable valve timing devices controlled by hydraulic pressure supplied from a hydraulic control valve are known (see Patent Documents 1 and 2). The variable valve timing device adjusts the relative rotational phase of the camshaft with respect to the crankshaft based on the hydraulic pressure supplied from the hydraulic control valve, thereby adjusting the opening and closing timing of the valves (valve timing).

[0003] The variable valve timing device described in Patent Document 1 is provided at the end of the intake camshaft and the end of the exhaust camshaft, and the hydraulic control valve is attached to the cam chain cover and is composed of an electromagnetic hydraulic control valve that supplies hydraulic pressure to the intake side variable valve timing device and the exhaust side variable valve timing device.

[0004] An oil passage is provided on the right side wall of the cylinder head to supply oil to the intake hydraulic control valve and the exhaust hydraulic control valve.

[0005] This oil passage includes a main oil passage that extends diagonally upward from the bottom surface of the right wall of the cylinder head, and an intake VVT ​​supply passage and an exhaust VVT supply passage that are provided on the right wall of the cylinder head and supply oil from the main oil passage to the intake side hydraulic control valve and the exhaust side hydraulic control valve, respectively.

[0006] The oil passage is provided on the right side wall of the cylinder head and has an intake side advance passage that changes the phase of the intake side camshaft relative to the crankshaft in the advance direction using oil pressure controlled by the intake side oil pressure control valve, and an intake side retard passage that changes the phase of the intake side camshaft relative to the crankshaft in the retard direction.

[0007] The oil passage is provided on the right side wall of the cylinder head and has an exhaust-side advance passage that changes the phase of the exhaust-side camshaft relative to the crankshaft in the advance direction using oil pressure controlled by the exhaust-side oil pressure control valve, and an exhaust-side retard passage that changes the phase of the exhaust-side camshaft relative to the crankshaft in the retard direction.

[0008] The variable valve timing device described in Patent Document 2 has a hydraulic control valve provided at the end of a camshaft, and an actuator unit installed on the outer periphery of the hydraulic control valve. The actuator unit includes a housing and a vane member that define an advance chamber and a retard chamber to which oil is supplied from the hydraulic control valve.

[0009] The variable valve timing device described in Patent Document 2 can install an actuator unit near the hydraulic control valve, thereby improving responsiveness when changing the valve timing. [Prior art documents] [Patent documents]

[0010] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-128682 [Patent Document 2] Japanese Patent Application Laid-Open No. 2018-3694 Summary of the Invention [Problem to be solved by the invention]

[0011] In an engine equipped with a variable valve timing device, activating the intake-side variable valve timing device as soon as possible after starting the engine is advantageous in terms of reducing exhaust gas emissions and improving fuel economy.

[0012] However, in order to quickly operate the intake side variable valve timing device after the engine has started, it is necessary to quickly supply oil to the intake side hydraulic control valve and accurately detect the hydraulic pressure supplied to the intake side hydraulic control valve.

[0013] The variable valve timing devices described in Patent Documents 1 and 2 do not mention how to quickly supply oil to the intake hydraulic control valve and how to accurately grasp the hydraulic pressure supplied to the intake hydraulic control valve, so there is still room for improvement.

[0014] The present invention has been made in response to the above-mentioned problems, and aims to provide an oil passage structure for an internal combustion engine that can quickly operate an intake side valve timing adjustment device after starting the internal combustion engine, thereby reducing exhaust gas and fuel consumption. [Means for solving the problem]

[0015] The present invention relates to a cylinder head having an end wall provided at an end in the axial direction of a crankshaft, and an intake side wall provided on a side surface in a width direction perpendicular to the axial direction of the crankshaft and to which an intake manifold is connected, a cam cap provided on an upper surface of the end wall, an intake camshaft rotatably supported in an intake side bearing portion formed on the upper surface of the end wall and the cam cap, an exhaust camshaft rotatably supported in an exhaust side bearing portion formed on the upper surface of the end wall and the cam cap, an intake side hydraulic control valve provided at an end of the intake camshaft, and an outer periphery of the intake side hydraulic control valve. an intake side valve timing adjusting device having an intake side actuator installed on an end of the exhaust camshaft and adjusting the relative rotation phase of the intake camshaft with respect to the crankshaft by oil supplied from the intake side hydraulic control valve; an exhaust side valve timing adjusting device having an exhaust side hydraulic control valve provided at an end of the exhaust camshaft and an exhaust side actuator installed on the outer periphery of the exhaust side hydraulic control valve and adjusting the relative rotation phase of the exhaust camshaft with oil supplied from the exhaust side hydraulic control valve; and a hydraulic sensor attached to the cylinder head. an intake-side cam cap oil passage that communicates with the intake-side head oil passage and the intake-side hydraulic control valve; and an exhaust-side cam cap oil passage that communicates with the exhaust-side head oil passage and the exhaust-side hydraulic control valve. The intake-side cam cap oil passage is disposed on an opposite side of the intake-side bearing portion from the exhaust-side bearing portion. the exhaust-side cam cap oil passage is disposed between the intake-side bearing portion and the exhaust-side bearing portion, the main oil passage and the exhaust-side head oil passage extend upward from below the exhaust-side cam cap oil passage toward the exhaust-side cam cap oil passage, the intake-side head oil passage has a first intake-side head oil passage extending from the main oil passage toward the intake side wall, and a second intake-side head oil passage extending upward from an outer end of the first intake-side head oil passage in an extending direction and reaching the intake-side cam cap oil passage, and the second intake-side head oil passageThe hydraulic pressure sensor is provided with a sensor mounting boss. [Effects of the Invention]

[0016] As described above, according to the present invention, the intake valve timing controller can be operated quickly after the internal combustion engine is started, thereby reducing exhaust gas and fuel consumption. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a front view of an internal combustion engine according to an embodiment of the present invention. [Figure 2] FIG. 2 is a top view of an internal combustion engine according to an embodiment of the present invention, showing a state in which the cylinder head cover has been removed. [Figure 3] FIG. 3 is a right side view of the upper part of an internal combustion engine according to one embodiment of the present invention. [Figure 4] 4 is a cross-sectional view taken along the line IV-IV in FIG. [Figure 5] FIG. 5 is a top view of an internal combustion engine according to one embodiment of the present invention, showing a state in which a cylinder head cover and a cam cap on the front wall side of the cylinder head have been removed. [Figure 6] FIG. 6 is a front side view of an upper portion of a cylinder head of an internal combustion engine according to one embodiment of the present invention. [Figure 7] 7 is a cross-sectional view taken along the line VII-VII in FIG. [Figure 8] 8 is a cross-sectional view taken along the line VIII-VIII in FIG. [Figure 9] 9 is a cross-sectional view taken along the line IX-IX in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0018] An oil passage structure for an internal combustion engine according to one embodiment of the present invention includes a cylinder head having an end wall provided at an axial end of a crankshaft and an intake side wall provided on a side surface in a width direction perpendicular to the axial direction of the crankshaft and to which an intake manifold is connected, a cam cap provided on an upper surface of the end wall, an intake camshaft rotatably supported by an intake side bearing portion formed on the upper surface of the end wall and the cam cap, an exhaust camshaft rotatably supported by an exhaust side bearing portion formed on the upper surface of the end wall and the cam cap, and an intake side hydraulic control valve provided at an end of the intake camshaft. an intake-side valve timing adjusting device having an intake-side actuator installed on the outer periphery of the intake-side hydraulic control valve and adjusting the relative rotation phase of the intake camshaft with respect to the crankshaft by oil supplied from the intake-side hydraulic control valve; an exhaust-side valve timing adjusting device having an exhaust-side hydraulic control valve provided at the end of the exhaust camshaft and an exhaust-side actuator installed on the outer periphery of the exhaust-side hydraulic control valve and adjusting the relative rotation phase of the exhaust camshaft with respect to the crankshaft by oil supplied from the exhaust-side hydraulic control valve; The oil passage structure of an internal combustion engine is provided with a sensor, and includes a main oil passage provided in an end wall and supplied with oil from a hydraulic source, an intake-side head oil passage and an exhaust-side head oil passage branching from the main oil passage to an upper surface of the end wall, an intake-side cam cap internal oil passage provided in the cam cap and communicating the intake-side head oil passage with an intake-side hydraulic control valve, and an exhaust-side cam cap internal oil passage provided in the cam cap and communicating the exhaust-side head oil passage with an exhaust-side hydraulic control valve, and the intake-side cam cap internal oil passage is provided on the opposite side of the intake-side bearing portion from the exhaust-side bearing portion .... The intake side cam cap oil passage is installed between the intake side bearing and the exhaust side bearing, and the main oil passage and the exhaust side head oil passage extend upward from below the exhaust side cam cap oil passage toward the exhaust side cam cap oil passage. The intake side head oil passage has a first intake side head oil passage extending from the main oil passage toward the intake side wall, and a second intake side head oil passage extending upward from the outer end in the extension direction of the first intake side head oil passage and reaching the intake side cam cap oil passage, and a sensor mounting boss for mounting a hydraulic sensor is provided on the second intake side head oil passage.

[0019] As a result, the oil passage structure of an internal combustion engine according to one embodiment of the present invention can quickly operate the intake side valve timing adjustment device after the internal combustion engine is started, thereby reducing exhaust gas emissions and fuel consumption. [Example]

[0020] Hereinafter, an embodiment of an oil passage structure for an internal combustion engine according to the present invention will be described with reference to the drawings. 1 to 9 are diagrams showing an oil passage structure of an internal combustion engine according to one embodiment of the present invention. In Fig. 1 to 9, the up, down, front, back, left and right directions are defined as follows.

[0021] The direction along the crankshaft is the front-to-rear direction of the engine, with the side where the timing chain is located being the front and the opposite side being the rear. The direction along the central axis of the cylinder is the up-down direction of the engine, with the cylinder head side being the top and the opposite side being the bottom. The direction intersecting the crankshaft and central axis of the cylinder is the left-to-right direction of the engine, with the left side of the central axis of the cylinder when looking at the crankshaft from the rear being the left and the right side of the central axis of the cylinder being the right.

[0022] First, the configuration will be described.

[0023] In Figure 1, engine 1 includes an engine body 2 and a chain cover 40. Engine body 2 includes a cylinder block 3, a cylinder head 4, a cylinder head cover 5, and an oil pan 6. Engine 1 of this embodiment constitutes an internal combustion engine. Virtual line 55 in Figure 1 is the boundary between cylinder block 3 and cylinder head 4.

[0024] The cylinder block 3 is provided with a plurality of cylinders (not shown), and the cylinders are arranged in a row in the front-to-rear direction of the engine 1. The engine 1 is installed so that the central axes 1C of the cylinders extend in the vertical direction.

[0025] Each cylinder houses a piston (not shown), and the pistons are connected to the crankshaft 7 via a connecting rod (not shown). The crankshaft 7 has a central axis of rotation that extends in the front-to-rear direction and rotates around the central axis of rotation.

[0026] The pistons reciprocate within the cylinders, rotating the crankshaft 7 via connecting rods. The cylinder head 4 is formed with a plurality of intake ports 4P (one of which is shown in Figures 8 and 9) and a plurality of exhaust ports (not shown).

[0027] The intake ports 4P are connected to the cylinders, respectively, and introduce intake air into the cylinders. The exhaust manifold is connected to multiple cylinders through exhaust ports, and collects exhaust gases discharged from the multiple cylinders and discharges them from an exhaust port to a catalytic converter (not shown).

[0028] 3 and 5, the cylinder head 4 has a front wall 4A and an intake side wall 4B. The front wall 4A is provided at the front end (end) in the axial direction of the crankshaft 7, and the intake side wall 4B is provided on the right side (side) of the cylinder head 4 in the width direction perpendicular to the axial direction of the crankshaft 7. In this embodiment, the front wall 4A constitutes an end wall.

[0029] An intake manifold 9 (shown by phantom lines in Figures 1 and 6) is attached to the intake side wall 4B of the cylinder head 4. The intake manifold 9 distributes the air that has been purified by an air cleaner (not shown) and then drawn into an intake pipe (not shown) to each intake port 4P of the cylinder head 4.

[0030] A valve train chamber 19 is formed inside the cylinder head 4 and the cylinder head cover 5, and an intake camshaft 11 and an exhaust camshaft 12 are rotatably supported in the cylinder head 4 (see Figure 2). That is, the intake camshaft 11 and the exhaust camshaft 12 are installed in the valve train chamber 19.

[0031] As shown in FIG. 2, the intake camshaft 11 and the exhaust camshaft 12 are arranged side by side in the left-right direction of the engine 1 such that the rotational axes 11a and 12a extend parallel to the front-rear direction of the engine 1.

[0032] The intake camshaft 11 is provided with a plurality of intake cams 11A (two in the figure), and the intake cams 11A are arranged side by side in the direction of the rotation center axis 11a of the intake camshaft 11.

[0033] For example, two intake cams 11A are provided for each cylinder. An intake valve (not shown) is provided in the intake port 4P, and the intake cam 11A operates the intake valve to open and close the intake port 4P, thereby connecting or blocking communication between the cylinder and the intake port 4P.

[0034] The exhaust camshaft 12 is provided with a plurality of exhaust cams 12A (two in the figure), and the exhaust cams 12A are arranged side by side in the direction of the rotational center axis 12a of the exhaust camshaft 12. Hereinafter, the direction of the rotational center axes 11a, 12a will be referred to as the axial direction.

[0035] For example, two exhaust cams 12A are provided for each cylinder. An exhaust valve (not shown) is provided in the exhaust port, and the exhaust cam 12A operates the exhaust valve to open and close the exhaust port, thereby connecting or blocking communication between the cylinder and the exhaust port.

[0036] 2, intake cam cap 13A, exhaust cam cap 13B, and cam cap 14 are attached to the top surface of cylinder head 4. Intake cam cap 13A and exhaust cam cap 13B are respectively installed between intake cams 11A and exhaust cams 12A provided for each cylinder in the axial direction of intake camshaft 11 and exhaust camshaft 12.

[0037] Intake cam bearing surfaces and exhaust cam bearing surfaces (not shown) are provided on the inner peripheral surfaces of intake cam cap 13A and exhaust cam cap 13B. Opposite the intake cam bearing surfaces and exhaust cam bearing surfaces are intake cam bearing surfaces and exhaust cam bearing surfaces (not shown) on the upper surface of cylinder head 4.

[0038] The intake cam cap 13A and the exhaust cam cap 13B are fixed to the upper surface of the cylinder head 4 by bolts 33A. The intake camshaft 11 is rotatably supported by the intake cam bearing surface of the intake cam cap 13A and the intake cam bearing surface of the cylinder head 4.

[0039] The exhaust camshaft 12 is rotatably supported by an exhaust cam bearing surface of the exhaust cam cap 13B and an exhaust cam bearing surface of the cylinder head 4.

[0040] 5 and 6, an intake-side bearing surface 4a and an exhaust-side bearing surface 4b are provided on the upper surface of the front wall 4A. As shown in Fig. 7, an intake-side bearing surface 14a and an exhaust-side bearing surface 14b are provided on the inner peripheral surface of the cam cap 14.

[0041] The intake camshaft 11 is rotatably supported by the intake side bearing surface 4a of the front wall 4A and the intake side bearing surface 14a of the cam cap 14, and the exhaust camshaft 12 is rotatably supported by the exhaust side bearing surface 4b of the front wall 4A and the exhaust side bearing surface 14b of the cam cap 14.

[0042] In this embodiment, the intake side bearing surface 4a and the intake side bearing surface 14a form an intake side bearing portion 17, and the exhaust side bearing surface 4b and the exhaust side bearing surface 14b form an exhaust side bearing portion 18.

[0043] As shown in FIGS. 2 and 7, the cam cap 14 is fixed to the upper surface of the front wall 4A of the cylinder head 4 by bolts 33B.

[0044] 5 and 6, bolt mounting bosses 31 and 32 are provided on the upper end of the front wall 4A of the cylinder head 4. The bolt mounting bosses 31 and 32 are installed on both sides of the intake-side bearing 17 (both sides in the left-right direction of the engine 1), and the intake-side bearing 17 is formed between the bolt mounting bosses 31 and 32 in the left-right direction of the engine 1.

[0045] The inner peripheral surfaces of the bolt mounting bosses 31 and 32 are formed with thread grooves 31a and 32a into which the bolt 33B is screwed.

[0046] Bolt mounting bosses 33, 34 are provided at the upper end of the front wall 4A of the cylinder head 4. The bolt mounting bosses 33, 34 are installed on both sides of the exhaust-side bearing 18 (both sides in the left-right direction of the engine 1), and the exhaust-side bearing 18 is formed between the bolt mounting bosses 33, 34 in the left-right direction of the engine 1.

[0047] The inner peripheral surfaces of the bolt mounting bosses 33 and 34 are formed with thread grooves 33a and 34a into which the bolt 33B is screwed.

[0048] 2, cam cap 14 is provided with bosses 14A, 14B, 14C, and 14D through which bolt 33B is inserted. Bolt 33B is threaded through bosses 14A, 14B, 14C, and 14D and into thread grooves 31a, 32a, 33a, and 34a, thereby attaching cam cap 14 to the upper surface of front wall 4A.

[0049] 2 and 3, an intake-side valve timing controller 15 is attached to the axial front end (end) of the intake camshaft 11. The intake-side valve timing controller 15 has an intake-side housing member 23, and an intake sprocket 23S is provided on the outer periphery of the intake-side housing member 23.

[0050] 2, an exhaust-side valve timing adjusting device 16 is attached to the axial front end (end) of the exhaust camshaft 12. The exhaust-side valve timing adjusting device 16 has an exhaust-side housing member 24, and an exhaust sprocket 24S is provided on the outer periphery of the exhaust-side housing member 24.

[0051] The length of the intake-side housing member 23 in the axial direction of the intake camshaft 11 and the exhaust camshaft 12 is formed to be longer than the length of the exhaust-side housing member 24 .

[0052] 1, a crank sprocket 7S is provided at the front end of the crankshaft 7. A timing chain 8 is wound around the crank sprocket 7S, the intake sprocket 23S, and the exhaust sprocket 24S.

[0053] The power of the crankshaft 7 is transmitted to the intake camshaft 11 and the exhaust camshaft 12 via the timing chain 8. As a result, the intake camshaft 11 rotates, causing the intake cam 11A to open and close the intake valve, and the exhaust camshaft 12 rotates, causing the exhaust cam 12A to open and close the exhaust valve.

[0054] The intake valve timing controller 15 adjusts the relative rotation phase of the intake camshaft 11 with respect to the crankshaft 7, thereby adjusting the opening and closing timing (valve timing) of the intake valves.

[0055] The exhaust-side valve timing adjuster 16 adjusts the relative rotation phase of the exhaust camshaft 12 with respect to the crankshaft 7, and adjusts the opening and closing timing (valve timing) of the exhaust valve.

[0056] 1, an oil pump 35 is provided in the cylinder block 3. The oil pump 35 is driven by the crankshaft 7 to supply oil stored in the oil pan 6 to various parts of the engine 1. In this embodiment, the oil pump 35 constitutes a hydraulic pressure source.

[0057] A chain cover 40 is attached to the front end (end) of the cylinder block 3 and the front end (end) of the cylinder head 4.

[0058] The chain cover 40 is formed so that the vertical direction of the chain cover 40 is longer than the horizontal direction of the chain cover 40, so that the longitudinal direction is along the vertical direction of the engine 1 and the lateral direction is along the horizontal direction of the engine 1. As shown in Figures 1 to 3, the chain cover 40 has a vertical wall 40A, a left side wall 40B, and a right side wall 40C.

[0059] The vertical wall 40A faces the front end portions of the cylinder block 3 and the cylinder head 4 in the axial direction of the intake camshaft 11 and the exhaust camshaft 12, respectively.

[0060] The left side wall 40B and the right side wall 40C protrude from the left and right ends of the chain cover 40 in the short side direction (left-right direction of the chain cover 40) toward the engine body 2, and their leading ends in the protruding direction are fastened to the front end of the cylinder block 3 and the front end of the cylinder head 4 by multiple bolts 33A (see FIG. 1). In this way, the chain cover 40 is fixed to the engine body 2.

[0061] As shown in FIG. 2, a chain chamber 20 is formed between the cylinder block 3, the cylinder head 4 and the chain cover 40, and the chain chamber 20 accommodates the timing chain 8, the intake valve timing adjuster 15 and the exhaust valve timing adjuster 16 (see FIG. 2).

[0062] 1, 2, 3 and 5, the timing chain 8 is shown by imaginary lines. The chain cover 40 of this embodiment constitutes a cover member.

[0063] As shown in Figures 1 and 2, an intake side vertical wall portion 41A and an exhaust side vertical wall portion 41B are provided on the upper part of the vertical wall 40A of the chain cover 40, and the intake side vertical wall portion 41A and the exhaust side vertical wall portion 41B are arranged in parallel in the width direction (short direction) of the chain cover 40.

[0064] The intake side vertical wall portion 41A faces the intake side valve timing control device 15 in the axial direction of the intake camshaft 11 and covers the intake side valve timing control device 15.

[0065] The exhaust-side vertical wall portion 41B faces the exhaust-side valve timing adjusting device 16 in the axial direction of the exhaust camshaft 12 and covers the exhaust-side valve timing adjusting device 16.

[0066] The exhaust-side vertical wall portion 41B is recessed toward the engine body 2 relative to the intake-side vertical wall portion 41A. That is, the exhaust-side vertical wall portion 41B is recessed toward the engine body 2 relative to the intake-side vertical wall portion 41A, and the intake-side vertical wall portion 41A bulges outward relative to the exhaust-side vertical wall portion 41B so as to move away from the engine body 2.

[0067] The intake-side vertical wall portion 41A and the exhaust-side vertical wall portion 41B are connected by a step portion 41C that has a step in the axial direction of the intake camshaft 11. In other words, the intake-side vertical wall portion 41A and the exhaust-side vertical wall portion 41B are separated in the axial direction of the intake camshaft 11 and the exhaust camshaft 12 by the step portion 41C.

[0068] 4, an intake-side vane rotor 23A is housed inside the intake-side housing member 23, and the intake-side vane rotor 23A rotates integrally with the intake camshaft 11. The intake-side vane rotor 23A divides the inside of the intake-side housing member 23 into a plurality of advance chambers and a plurality of retard chambers (not shown).

[0069] The intake valve timing controller 15 is provided with an intake spool valve 25 . The intake spool valve 25 is disposed axially of the intake camshaft 11, rotates integrally with the intake camshaft 11, and has a valve body that is movable in the axial direction of the intake camshaft 11.

[0070] As shown in Fig. 1, an intake-side solenoid 52 is provided on the intake-side vertical wall portion 41A of the chain cover 40. As shown in Fig. 4, the intake-side solenoid 52 is attached to the intake-side vertical wall portion 41A so as to face the intake-side spool valve 25 in the axial direction of the intake camshaft 11.

[0071] The intake side solenoid 52 operates the intake side spool valve 25 so that the valve element of the intake side spool valve 25 moves in the axial direction of the intake camshaft 11 .

[0072] When the intake solenoid 52 moves the valve element of the intake spool valve 25 to the advance chamber position in the axial direction of the intake camshaft 11, oil is supplied from the oil pump 35 to the advance chamber. The oil passage from the oil pump 35 to the intake valve timing controller 15 will be described later.

[0073] When oil is supplied to the advance chamber, the intake side vane rotor 23A rotates relative to the intake side housing member 23, thereby adjusting the relative rotation phase of the intake camshaft 11 to the crankshaft 7 to the advance side, and adjusting the opening and closing timing of the intake valve to the advance side.

[0074] When the intake solenoid 52 moves the valve element of the intake spool valve 25 to a position on the retard chamber side in the axial direction of the intake camshaft 11, oil supplied from the oil pump 35 is supplied to the retard chamber.

[0075] When oil is supplied to the retard chamber, the intake side vane rotor 23A rotates relative to the intake side housing member 23, thereby adjusting the relative rotational phase of the intake camshaft 11 to the crankshaft 7 to a retarded angle, and adjusting the opening and closing timing of the exhaust valve to the retarded side.

[0076] In this way, the intake spool valve 25 and intake solenoid 52 of this embodiment operate the intake valve timing adjuster 15 by oil, and adjust the relative rotational phase of the intake camshaft 11 with respect to the crankshaft 7.

[0077] In this embodiment, the intake-side spool valve 25 constitutes an intake-side hydraulic control valve. The intake-side housing member 23 and the intake-side vane rotor 23A are installed on the outer periphery of the intake-side spool valve 25 and constitute an intake-side actuator that adjusts the relative rotational phase of the intake camshaft 11 with respect to the crankshaft 7 using oil supplied from the intake-side spool valve 25.

[0078] An exhaust-side vane rotor 24A is housed inside the exhaust-side housing member 24, and the exhaust-side vane rotor 24A rotates integrally with the exhaust camshaft 12. The exhaust-side vane rotor 24A divides the inside of the exhaust-side housing member 24 into a plurality of advance chambers and a plurality of retard chambers (not shown).

[0079] 4, the exhaust-side valve timing controller 16 is provided with an exhaust-side spool valve 26. The exhaust-side spool valve 26 is installed axially on the exhaust camshaft 12, rotates integrally with the exhaust camshaft 12, and has a valve body that is movable in the axial direction of the exhaust camshaft 12.

[0080] As shown in Fig. 1, an exhaust-side solenoid 53 is provided on the exhaust-side vertical wall portion 41B of the chain cover 40. As shown in Fig. 4, the exhaust-side solenoid 53 is attached to the exhaust-side vertical wall portion 41B so as to face the exhaust-side spool valve 26 in the axial direction of the exhaust camshaft 12.

[0081] The exhaust spool valve 26 is operated by the exhaust solenoid 53 to supply oil to either the advance chamber or the retard chamber, similar to the intake valve timing controller 15. This adjusts the relative rotational phase of the exhaust camshaft 12 with respect to the crankshaft 7 to the advance or retard side, thereby adjusting the opening and closing timing of the exhaust valve to the advance or retard side.

[0082] The exhaust-side spool valve 26 of this embodiment constitutes an exhaust-side hydraulic control valve. The exhaust-side housing member 24 and the exhaust-side vane rotor 24A are installed on the outer periphery of the exhaust-side spool valve 26 and constitute an exhaust-side actuator that adjusts the relative rotational phase of the exhaust camshaft 12 with respect to the crankshaft 7 using oil supplied from the exhaust-side spool valve 26.

[0083] As shown in FIGS. 1 and 3, a mount attachment portion 44 is provided on the upper portion of the vertical wall 40A of the chain cover 40.

[0084] The mount attachment portion 44 is located below the intake side vertical wall portion 41A and the exhaust side vertical wall portion 41B, and bulges out in a direction away from the engine body 2 (forward) relative to the chain cover 40.

[0085] As shown in FIG. 3, a side member 10 is provided in front of the engine 1, and the side member 10 extends in the front-rear direction.

[0086] An attachment seat 44a is provided at the tip of the mount attachment portion 44 (see Figures 2 and 4), and bolt holes 44b, 44c, and 44d are formed in the attachment seat 44a to fasten bolts as fasteners (not shown).

[0087] 3, a mount member 51 is attached to the mounting seat 44a. The mount member 51 includes a mount bracket 51A, and a bolt is inserted into the rear end of the mount bracket 51A.

[0088] Bolts inserted into the rear end portion of the mount bracket 51A are fastened to the bolt holes 44b, 44c, and 44d, thereby fixing the rear end portion of the mount bracket 51A to the attachment seat 44a.

[0089] The mount member 51 is provided with a vibration absorbing member 51B, which is attached to the side member 10. The front end of the mount bracket 51A is attached to the vibration absorbing member 51B, and the engine body 2 is elastically supported on the side member 10 via the mount member 51.

[0090] This allows the mount member 51 to absorb vibrations of the engine 1, thereby suppressing vibrations transmitted from the engine 1 to the side member 10. As shown in Figures 6 and 7, an oil passage 61 is provided in the front wall 4A of the cylinder head 4.

[0091] The oil passage 61 has a main oil passage 62, an intake side head oil passage 63, an exhaust side head oil passage 64, an intake side cam cap oil passage 65, an exhaust side cam cap oil passage 66, an intake camshaft oil passage 67, and an exhaust camshaft oil passage 68.

[0092] The oil passage 61 in this embodiment is configured to include a cylindrical portion that bulges out from the front wall 4A and an oil passage that is provided inside the cylindrical portion and through which oil flows.

[0093] The main oil passage 62 extends linearly in the vertical direction from the lower surface to the upper surface of the cylinder head 4, and oil is supplied to the main oil passage 62 from the oil pump 35. The upstream side of the main oil passage 62 communicates with a block-side oil passage (not shown) provided in the cylinder block 3, and the block-side oil passage guides oil discharged from the oil pump 35 to the main oil passage 62. Here, upstream and downstream refer to the upstream and downstream directions of the oil flow.

[0094] The intake-side head oil passage 63 branches off from the main oil passage 62 and reaches the upper surface of the front wall 4A. Specifically, as shown in Fig. 7, the intake-side head oil passage 63 has a first intake-side head oil passage 63A that extends linearly from a branching portion 62a of the main oil passage 62 toward the intake-side wall 4B, and a second intake-side head oil passage 63B that extends linearly upward from an outer end portion 63a in the extension direction of the first intake-side head oil passage 63A and reaches the intake-side cam cap oil passage 65.

[0095] The exhaust-side head oil passage 64 branches off from the branching portion 62a of the main oil passage 62, extends upward in a straight line from the branching portion 62a, and reaches the upper surface of the front wall 4A.

[0096] The main oil passage 62 in the cylinder head 4 is made up of an oil passage extending from the lower end of the front wall 4A to a branching portion 62a where an intake-side head oil passage 63 and an exhaust-side head oil passage 64 branch off.

[0097] In this manner, the main oil passage 62 and the exhaust-side head oil passage 64 of this embodiment extend linearly upward from below the exhaust-side cam cap oil passage 66 toward the exhaust-side cam cap oil passage 66 .

[0098] The intake-side cam cap oil passage 65 is provided inside the cam cap 14, and connects the second intake-side head oil passage 63B with the intake camshaft oil passage 67. The intake camshaft oil passage 67 is provided at the end of the intake camshaft 11, and connects the second intake-side head oil passage 63B with the oil passage of the intake spool valve 25.

[0099] The intake side spool valve 25 is controlled by the intake side solenoid 52 to supply oil supplied from the oil passage 67 in the intake camshaft to the advance chamber or retard chamber of the intake side valve timing controller 15 .

[0100] The exhaust-side cam cap oil passage 66 is provided inside the cam cap 14, and connects the exhaust-side head oil passage 64 with the exhaust camshaft oil passage 68. The exhaust camshaft oil passage 68 is provided at the end of the exhaust camshaft 12, and connects the exhaust-side head oil passage 64 with the oil passage of the exhaust-side spool valve 26.

[0101] The exhaust-side spool valve 26 is controlled by the exhaust-side solenoid 53 to supply oil supplied from an oil passage 68 in the exhaust camshaft to an advance chamber or a retard chamber of the exhaust-side valve timing controller 16 .

[0102] The intake side cam cap oil passage 65 is arranged alongside the exhaust side cam cap oil passage 66 in the left-right direction of the engine 1, and is arranged on the opposite side of the intake side bearing portion 17 from the exhaust side bearing portion 18.

[0103] That is, the oil passage 65 inside the intake side cam cap is located on the intake side wall 4B side relative to the intake side bearing portion 17, and the oil passage 66 inside the exhaust side cam cap is located between the intake side bearing portion 17 and the exhaust side bearing portion 18.

[0104] The intake side cam cap oil passage 65 and the exhaust side cam cap oil passage 66 are installed side by side in the left-right direction of the engine 1 at the same height position, and the length of the intake side cam cap oil passage 65 along the left-right direction of the engine 1 is formed shorter than the length of the exhaust side cam cap oil passage 66 along the left-right direction of the engine 1.

[0105] 7 and 9, a sensor mounting boss 69 is provided in the second intake-side head oil passage 63B, and a sensor hole 69a is provided inside the sensor mounting boss 69. An oil pressure sensor 70 is inserted into the sensor hole 69a, and the oil pressure sensor 70 is attached to the sensor mounting boss 69.

[0106] The oil pressure sensor 70 detects the pressure (oil pressure) of the oil flowing through the second intake-side head oil passage 63B, and transmits a signal to a controller (not shown).

[0107] The controller controls the intake solenoid 52 and the exhaust solenoid 53 based on the oil pressure sensor 70 to adjust the relative rotation phase of the intake camshaft 11 with respect to the crankshaft 7 and the relative rotation phase of the exhaust camshaft 12 with respect to the crankshaft 7 .

[0108] As shown in FIG. 6, the second intake-side head oil passage 63B has an upper end portion 63b located on the intake-side wall 4B side relative to the bolt mounting bosses 31, 32.

[0109] As shown in Figure 5, the second intake side head oil passage 63B is located on the opposite side of the intake side valve timing adjuster 15 from the bolt mounting bosses 31 and 32 in the axial direction of the intake camshaft 11, and is adjacent to the bolt mounting boss 31 in the left-right direction of the engine 1.

[0110] As shown in Figures 6 and 7, the second intake side head oil passage 63B is inclined so as to approach the intake side wall 4B as it moves from the upper end 63b to the lower end 63c, and extends diagonally upward to the left from the outer end 63a of the first intake side head oil passage 63A toward the intake side bearing portion 17.

[0111] As shown in Figures 6 and 8, the bolt mounting bosses 31, 32 bulge from the front wall 4A toward the intake-side valve timing adjuster 15 in the axial direction of the intake camshaft 11, and a space 71 is formed below the bolt mounting bosses 31, 32.

[0112] As shown in Figure 6, the sensor hole portion 69a protrudes toward the bolt mounting bosses 31, 32 from the outer wall 63d of the second intake side head oil passage 63B, and extends toward the bolt mounting bosses 31, 32 further than the second intake side head oil passage 63B.

[0113] A space 71 is formed between the sensor mounting boss 69 and the bolt mounting bosses 31, 32, and the sensor mounting boss 69 bulges into the space 71 from the second intake-side head oil passage 63B.

[0114] As shown in FIGS. 6 and 7, a first communication oil passage 72, a second communication oil passage 73, an intake-side lash adjuster oil passage 74, and an exhaust-side lash adjuster oil passage 75 are provided in the front wall 4A.

[0115] The first communication oil passage 72 connects the exhaust-side cam cap oil passage 66 with the intake-side lash adjuster oil passage 74. The intake-side lash adjuster oil passage 74 extends in the front-to-rear direction of the cylinder head 4, and supplies operating oil to the intake-side lash adjuster 36A.

[0116] The second communication oil passage 73 connects the exhaust-side cam cap oil passage 66 with the exhaust-side lash adjuster oil passage 75. The exhaust-side lash adjuster oil passage 75 extends in the front-to-rear direction of the cylinder head 4 in parallel with the intake-side lash adjuster oil passage 74, and supplies operating oil to an exhaust-side lash adjuster (not shown).

[0117] Next, the effect of the oil passage structure of the engine 1 of this embodiment will be described. The oil passage structure of the engine 1 of this embodiment includes a main oil passage 62 provided in the front wall 4A of the cylinder head 4 and supplied with oil from the oil pump 35, and an intake side head oil passage 63 and an exhaust side head oil passage 64 branching from the main oil passage 62 and reaching the upper surface of the front wall 4A.

[0118] In addition, the oil passage structure of the engine 1 of this embodiment includes an intake side cam cap oil passage 65 that is provided within the cam cap 14 and connects the intake side head oil passage 63 to the intake side spool valve 25, and an exhaust side cam cap oil passage 66 that is provided within the cam cap 14 and connects the exhaust side head oil passage 64 to the exhaust side spool valve 26.

[0119] The oil passage 65 in the intake cam cap communicates with the intake spool valve 25 through an oil passage 67 in the intake camshaft, and the oil passage 66 in the exhaust cam cap communicates with the exhaust spool valve 26 through an oil passage 68 in the exhaust camshaft.

[0120] As a result, oil supplied from the oil pump 35 to the main oil passage 62 is branched from the main oil passage 62 into an intake-side head oil passage 63 and an exhaust-side head oil passage 64 .

[0121] The oil branched from the main oil passage 62 to the intake head oil passage 63 is supplied from the intake head oil passage 63 to the intake spool valve 25 via the intake cam cap oil passage 65 and the intake camshaft oil passage 67 .

[0122] On the other hand, oil branched from the main oil passage 62 to the exhaust-side head oil passage 64 is supplied from the exhaust-side head oil passage 64 to the exhaust-side spool valve 26 via an exhaust-side cam cap oil passage 66 and an exhaust camshaft oil passage 68 .

[0123] Here, after the engine 1 is stopped, the oil pressure in the oil passage 61 drops due to oil leakage from the oil passage 61 or the like.

[0124] For this reason, after the engine 1 starts, the oil pump 35 sends oil to the oil passage 61, and when the pressure of the oil pressure sensor 70 reaches a predetermined pressure, the controller outputs a drive signal to the intake side solenoid 52 and the exhaust side solenoid 53 to operate the intake side valve timing adjuster 15 and the exhaust side valve timing adjuster 16.

[0125] At this time, operating the intake valve timing controller 15 as early as possible is advantageous for reducing exhaust gas and improving fuel economy.

[0126] In order to operate the intake side valve timing controller 15 quickly after the engine 1 starts, it is necessary to quickly supply oil to the intake side spool valve 25 of the intake side valve timing controller 15 and to accurately detect the oil pressure supplied to the intake side spool valve 25 using the oil pressure sensor 70.

[0127] According to the oil passage structure of the engine 1 of this embodiment, the oil passage 65 inside the intake side cam cap is installed on the opposite side of the intake side bearing 17 from the exhaust side bearing 18, and the oil passage 66 inside the exhaust side cam cap is installed between the intake side bearing 17 and the exhaust side bearing 18.

[0128] The main oil passage 62 and the exhaust-side head oil passage 64 extend upward from below the exhaust-side cam cap oil passage 66 toward the exhaust-side cam cap oil passage 66 .

[0129] The intake side head oil passage 63 has a first intake side head oil passage 63A extending from the main oil passage 62 toward the intake side wall 4B of the cylinder head 4, and a second intake side head oil passage 63B extending upward from the outer end 63a in the extension direction of the first intake side head oil passage 63A and reaching the intake side cam cap oil passage 65.

[0130] In addition, a sensor mounting boss 69 for mounting an oil pressure sensor 70 is provided in the second intake head oil passage 63B.

[0131] In this way, in the oil passage structure of engine 1, the intake side cam cap oil passage 65 is installed on the opposite side of the exhaust side bearing portion relative to the intake side bearing portion 17, and the second intake side head oil passage 63B extends upward from the outer end portion 63a in the extension direction of the first intake side head oil passage 63A, and reaches the intake side cam cap oil passage 65.

[0132] This allows the intake-side cam cap oil passage 65 and the second intake-side head oil passage 63B to be closer to the intake side wall 4B of the cylinder head 4 in the direction intersecting the intake camshaft 11 (the width direction of the cylinder head 4).

[0133] Therefore, the oil pressure sensor 70 can be easily attached to the second intake-side head oil passage 63B through the intake-side wall 4B of the cylinder head 4.

[0134] In addition, in the oil passage structure of the engine 1, an exhaust side cam cap oil passage 66 is installed between the intake side bearing 17 and the exhaust side bearing 18, the main oil passage 62 and the exhaust side head oil passage 64 extend upward from below the exhaust side cam cap oil passage 66 toward the exhaust side cam cap oil passage 66, and the first intake side head oil passage 63A extends from the main oil passage 62 toward the intake side wall 4B of the cylinder head 4.

[0135] This allows the main oil passage 62 and the exhaust side head oil passage 64 to be closer to the second intake side head oil passage 63B in a direction intersecting the intake camshaft 11, thereby shortening the length of the first intake side head oil passage 63A connected to the main oil passage 62.

[0136] Therefore, after the engine 1 starts, oil can be quickly supplied to the intake side spool valve 25 from the main oil passage 62 through the first intake side head oil passage 63A and the second intake side head oil passage 63B.

[0137] In addition, since the sensor mounting boss 69 for mounting the oil pressure sensor 70 is attached to the second intake side head oil passage 63B, the oil pressure sensor 70 can be brought closer to the intake side spool valve 25 and the oil pressure in the second intake side head oil passage 63B can be quickly increased, so the oil pressure supplied to the intake side spool valve 25 can be detected more accurately.

[0138] As described above, the oil passage structure of the engine 1 of this embodiment can quickly supply oil to the intake side spool valve 25 after the engine 1 is started, and can accurately detect the oil pressure supplied to the intake side spool valve 25, so that the intake side valve timing adjuster 15 can be operated quickly after the engine 1 is started, thereby reducing exhaust gas and fuel consumption.

[0139] Furthermore, according to the oil passage structure of the engine 1 of this embodiment, bolt mounting bosses 31, 32 for attaching the cam cap 14 to the upper surface of the front wall 4A are provided at the upper end of the front wall 4A, and the bolt mounting bosses 31, 32 are installed on both sides of the intake side bearing portion 17.

[0140] The second intake side head oil passage 63B has an upper end 63b located on the intake side wall 4B side relative to the bolt mounting bosses 31, 32, and is located on the opposite side of the intake side valve timing adjustment device 15 relative to the bolt mounting bosses 31, 32 in the axial direction of the intake camshaft 11, adjacent to the bolt mounting boss 31.

[0141] In addition, the second intake-side head oil passage 63B is inclined so as to approach the intake-side wall 4B from the upper end 63b toward the lower end 63c.

[0142] This allows the oil pressure sensor 70 to be easily attached to the sensor attachment boss 69 with the middle portion of the second intake side head oil passage 63B in the extending direction approaching the intake side wall 4B of the cylinder head 4.

[0143] In addition, the upper end 63b of the second intake-side head oil passage 63B can be brought closer to the intake-side bearing 17, allowing the oil pressure sensor 70 to be brought even closer to the intake-side spool valve 25. As a result, the oil pressure supplied to the intake-side spool valve 25 can be accurately detected by the oil pressure sensor 70.

[0144] Furthermore, according to the oil passage structure of the engine 1 of this embodiment, the bolt mounting bosses 31, 32 bulge out from the front wall 4A toward the intake side valve timing adjuster 15 in the axial direction of the intake camshaft 11 so that a space 71 is formed below them, and a sensor hole 69a is provided inside the sensor mounting boss 69.

[0145] In addition, the sensor hole portion 69a protrudes toward the bolt mounting bosses 31, 32 from the outer wall 63d of the second intake side head oil passage 63B, and extends toward the bolt mounting bosses 31, 32 further than the second intake side head oil passage 63B, and a space 71 is formed between the sensor mounting boss 69 and the bolt mounting bosses 31, 32.

[0146] This allows the sensor mounting boss 69 to be closer to the intake-side bearing 17 in the direction intersecting the intake camshaft 11, and allows the oil pressure sensor 70 to be closer to the intake-side spool valve 25. As a result, the oil pressure supplied to the intake-side spool valve 25 can be detected more accurately by the oil pressure sensor 70.

[0147] Furthermore, by providing a space 71 between the sensor mounting boss 69 and the bolt mounting bosses 31, 32, it is possible to prevent the sensor hole portion 69a from communicating with the bolt mounting bosses 31, 32 due to blowholes when manufacturing the cylinder head 4 by casting.

[0148] In other words, by forming a space 71 in advance in the thick-walled portion where the sensor hole portion 69a and the bolt mounting bosses 31, 32 are connected by a blowhole, it is possible to prevent the sensor hole portion 69a and the bolt mounting bosses 31, 32 from being connected by a blowhole.

[0149] While an embodiment of the present invention has been disclosed, it will be apparent to those skilled in the art that modifications may be made without departing from the scope of the invention, and all such modifications and equivalents are intended to be encompassed by the following claims. [Explanation of symbols]

[0150] 1...engine (internal combustion engine), 4...cylinder head, 4A...front wall (end wall), 4B...intake side wall, 7...crankshaft, 9...intake manifold, 11...intake camshaft, 12...exhaust camshaft, 14...cam cap, 15...intake side valve timing adjustment device, 16...exhaust side valve timing adjustment device, 17...intake side bearing, 18...exhaust side bearing, 23...intake side housing member (intake side actuator), 23A...intake side vane rotor (intake side actuator), 24...exhaust side housing member (exhaust side actuator), 24A...exhaust side vane rotor (exhaust side actuator), 25...intake side spool valve (intake side hydraulic control control valve), 26...exhaust side spool valve (exhaust side hydraulic control valve), 31, 32...bolt mounting boss, 62...main oil passage, 63...intake side head oil passage, 63A...first intake side head oil passage, 63a...outer end (outer end of first intake side head oil passage), 63B...second intake side head oil passage, 63b...upper end (upper end of second intake side head oil passage), 63c...lower end (lower end of second intake side head oil passage), 63d...outer wall (outer wall of second intake side head oil passage), 64...exhaust side head oil passage, 65...intake side cam cap internal oil passage, 66...exhaust side cam cap internal oil passage, 69...sensor mounting boss, 69a...sensor hole, 70...hydraulic pressure sensor, 71...space

Claims

1. a cylinder head including an end wall provided at an end in an axial direction of a crankshaft, and an intake side wall provided on a side surface in a width direction perpendicular to the axial direction of the crankshaft, the intake side wall being connected to an intake manifold; a cam cap provided on an upper surface of the end wall; an intake camshaft rotatably supported by an intake side bearing portion formed on an upper surface of the end wall and the cam cap; an exhaust camshaft rotatably supported by an exhaust-side bearing portion formed on an upper surface of the end wall and the cam cap; an intake side valve timing control device including an intake side hydraulic control valve provided at an end of the intake camshaft, and an intake side actuator installed on an outer periphery of the intake side hydraulic control valve and configured to adjust a relative rotation phase of the intake camshaft with respect to the crankshaft by oil supplied from the intake side hydraulic control valve; an exhaust-side valve timing control device including an exhaust-side hydraulic control valve provided at an end of the exhaust camshaft, and an exhaust-side actuator installed on an outer periphery of the exhaust-side hydraulic control valve and configured to adjust a relative rotation phase of the exhaust camshaft with respect to the crankshaft by oil supplied from the exhaust-side hydraulic control valve; An oil passage structure for an internal combustion engine comprising a hydraulic pressure sensor attached to the cylinder head, a main oil passage provided in the end wall and supplied with oil from a hydraulic source; an intake side head oil passage and an exhaust side head oil passage branching from the main oil passage and reaching an upper surface of the end wall; an intake-side cam cap inner oil passage provided in the cam cap and communicating between the intake-side head oil passage and the intake-side hydraulic control valve; an exhaust-side cam cap inner oil passage provided in the cam cap and communicating between the exhaust-side head oil passage and the exhaust-side hydraulic control valve; the intake-side cam cap oil passage is disposed on an opposite side of the intake-side bearing portion from the exhaust-side bearing portion, the exhaust-side cam cap oil passage is disposed between the intake-side bearing portion and the exhaust-side bearing portion, the main oil passage and the exhaust-side head oil passage extend upward from below the exhaust-side cam cap oil passage toward the exhaust-side cam cap oil passage, the intake side head oil passage includes a first intake side head oil passage extending from the main oil passage toward the intake side wall, and a second intake side head oil passage extending upward from an outer end of the first intake side head oil passage in an extending direction thereof and reaching the intake side cam cap oil passage, 2. An oil passage structure for an internal combustion engine, wherein the second intake head oil passage is provided with a sensor mounting boss for mounting the oil pressure sensor.

2. a pair of bolt mounting bosses are provided at an upper end of the end wall for mounting the cam cap to the upper surface of the end wall; The pair of bolt mounting bosses are provided on both sides of the intake side bearing portion, an upper end portion of the second intake side head oil passage is located on the intake side wall side with respect to the pair of bolt mounting bosses, and is located on the opposite side of the intake side valve timing adjusting device with respect to the pair of bolt mounting bosses in the axial direction of the intake camshaft, and is adjacent to one of the pair of bolt mounting bosses; 2. The oil passage structure of an internal combustion engine according to claim 1, wherein the second intake side head oil passage is inclined so as to approach the intake side wall from its upper end toward its lower end.

3. the bolt mounting boss bulges from the end wall toward the intake-side valve timing controller in the axial direction of the intake camshaft so as to define a space therebelow, a sensor hole portion is provided inside the sensor mounting boss, the sensor hole protrudes from an outer wall of the second intake head oil passage toward the bolt mounting boss and extends toward the bolt mounting boss further than the second intake head oil passage, 3. The oil passage structure of an internal combustion engine according to claim 2, wherein the space is formed between the sensor mounting boss and the bolt mounting boss.

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