阅读说明：本技术 内燃机 (Internal combustion engine ) 是由 远藤庆 于 2019-06-18 设计创作，主要内容包括：本发明涉及内燃机。内燃机具有排气侧和进气侧气门正时可变机构、在汽缸盖的内部划分出来的油路、从油路分支并向排气侧气门正时可变机构引导油的排气侧连接通路、以及从油路分支并向进气侧气门正时可变机构引导油的进气侧连接通路。向排气侧和进气侧气门正时可变机构中的、在供给具有相同压力的油而进行了动作时油的泄漏多的气门正时可变机构引导油的连接通路,与向油的泄漏少的气门正时可变机构引导油的连接通路相比在油路上位于下游。(The present invention relates to internal combustion engines. The internal combustion engine includes an exhaust-side and intake-side valve timing variable mechanism, an oil passage divided inside a cylinder head, an exhaust-side connecting passage branched from the oil passage and guiding oil to the exhaust-side valve timing variable mechanism, and an intake-side connecting passage branched from the oil passage and guiding oil to the intake-side valve timing variable mechanism. The connecting passage for guiding oil to the valve timing variable mechanism, which is operated by supplying oil having the same pressure, and which has a large amount of oil leakage, is located downstream in the oil passage than the connecting passage for guiding oil to the valve timing variable mechanism, which has a small amount of oil leakage.)

1. An internal combustion engine having:

a cylinder head;

an exhaust-side camshaft assembled to the cylinder head;

an intake side camshaft assembled to the cylinder head;

an exhaust side valve timing variable mechanism that is attached to an end portion of the exhaust side camshaft and changes an opening and closing timing of an exhaust valve by supply and discharge of oil;

an intake side valve timing variable mechanism that is attached to an end portion of the intake side camshaft and changes an opening and closing timing of an intake valve by supply and discharge of oil;

an oil passage defined in the cylinder head and through which oil pumped by an oil pump flows;

an exhaust-side connection passage connected to the oil passage, branched from the oil passage, and guiding oil to the exhaust-side variable valve timing mechanism; and

an intake-side connecting passage connected to the oil passage, branched from the oil passage, and guiding oil to the intake-side variable valve timing mechanism;

the connection passage for guiding oil to the valve timing variable mechanism, which is operated by supplying oil having the same pressure, and in which the amount of oil leakage is large, of the exhaust side valve timing variable mechanism and the intake side valve timing variable mechanism is located downstream in the oil passage than the connection passage for guiding oil to the valve timing variable mechanism in which the amount of oil leakage is small.

2. The internal combustion engine according to claim 1,

the internal combustion engine further has:

an exhaust side cam sprocket fixed to an end of the exhaust side camshaft,

an intake side cam sprocket fixed to an end portion of the intake side camshaft,

a crankshaft sprocket fixed to an end of the crankshaft, an

A timing chain that is wound around the exhaust side cam sprocket, the intake side cam sprocket, and the crankshaft sprocket and transmits rotational torque;

when the side of the exhaust side and the intake side where the valve timing variable mechanism with less oil leakage is provided is defined as the upstream side and the side where the valve timing variable mechanism with more oil leakage is provided is defined as the downstream side,

the downstream cam sprocket is located farther from the crankshaft sprocket than the upstream cam sprocket in the traveling direction of the timing chain.

3. The internal combustion engine according to claim 1 or 2,

the internal combustion engine further includes an oil control valve that is connected to the exhaust-side valve timing variable mechanism and the intake-side valve timing variable mechanism, respectively, and that controls supply and discharge of oil;

at least an oil control valve connected to a valve timing variable mechanism with a large amount of oil leakage is inserted into a radial center portion of the corresponding valve timing variable mechanism.

4. The internal combustion engine according to any one of claims 1 to 3,

the internal combustion engine further includes an injection connection passage provided in the oil passage and guiding oil to an oil injection nozzle that injects the oil;

the injection connection passage is located upstream of the oil passage with respect to a connection passage that leads oil to the variable valve timing mechanism having a large amount of oil leakage in the exhaust side variable valve timing mechanism and the intake side variable valve timing mechanism.

5. An internal combustion engine having:

a cylinder head;

an exhaust-side camshaft assembled to the cylinder head;

an intake side camshaft assembled to the cylinder head;

an exhaust side valve timing variable mechanism that is attached to an end portion of the exhaust side camshaft and changes an opening and closing timing of an exhaust valve by supply and discharge of oil;

an intake side valve timing variable mechanism that is attached to an end portion of the intake side camshaft and changes an opening and closing timing of an intake valve by supply and discharge of oil;

an oil passage defined in the cylinder head and through which oil pumped by an oil pump flows;

an exhaust-side connection passage connected to the oil passage, branched from the oil passage, and guiding oil to the exhaust-side variable valve timing mechanism; and

an intake-side connecting passage connected to the oil passage, branched from the oil passage downstream of the exhaust-side connecting passage, and guiding oil to the intake-side variable valve timing mechanism;

wherein when the exhaust side valve timing variable mechanism and the intake side valve timing variable mechanism are operated by being supplied with oil having the same pressure, the leakage of oil from the intake side valve timing variable mechanism is larger than the leakage of oil from the exhaust side valve timing variable mechanism.

Technical Field

The present disclosure relates to internal combustion engines.

Background

An internal combustion engine disclosed in japanese patent application laid-open No. 2016-. Further, an intake side valve timing variable mechanism is attached to an end portion of the intake side camshaft. An exhaust side valve timing variable mechanism is attached to an end portion of the exhaust side camshaft. A main oil passage through which oil flows is defined in the cylinder head. An intake-side connecting passage for supplying oil to the intake-side variable valve timing mechanism is connected to the main oil passage. Further, an exhaust-side connecting passage for supplying oil to the exhaust-side variable valve timing mechanism is connected to the main oil passage downstream of the intake-side connecting passage.

The oil pumped up by the oil pump is supplied from a main oil passage of the cylinder head to the intake-side valve timing variable mechanism via an intake-side connecting passage, and is supplied from the main oil passage to the exhaust-side valve timing variable mechanism via an exhaust-side connecting passage. Then, oil is supplied to and discharged from the intake-side variable valve timing mechanism and the exhaust-side variable valve timing mechanism in accordance with the operating state of the internal combustion engine. Thus, the opening and closing timings of the intake valve and the exhaust valve are advanced (advanced) or retarded (retarded) by changing the phases of the intake-side camshaft and the exhaust-side camshaft with respect to the crank angle.

In the internal combustion engine described above, oil supplied to the intake-side valve timing variable mechanism and the exhaust-side valve timing variable mechanism may leak from the inside to the outside of these valve timing variable mechanisms. Therefore, the hydraulic pressure on the downstream side of the main oil passage is reduced by the amount of the hydraulic pressure reduction on the upstream side of the main oil passage. Therefore, the valve timing variable mechanism located on the downstream side of the main oil passage, out of the intake-side valve timing variable mechanism and the exhaust-side valve timing variable mechanism, may have a shortage of oil pressure.

Disclosure of Invention

An internal combustion engine according to one aspect includes: a cylinder head; an exhaust-side camshaft assembled to the cylinder head; an intake side camshaft assembled to the cylinder head; an exhaust side valve timing variable mechanism that is attached to an end portion of the exhaust side camshaft and changes an opening and closing timing of an exhaust valve by supply and discharge of oil; an intake side valve timing variable mechanism that is attached to an end portion of the intake side camshaft and changes an opening and closing timing of an intake valve by supply and discharge of oil; an oil passage defined in the cylinder head and through which oil pumped by an oil pump flows; an exhaust-side connection passage connected to the oil passage, branched from the oil passage, and guiding oil to the exhaust-side variable valve timing mechanism; and an intake-side connection passage connected to the oil passage, branched from the oil passage, and guiding oil to the intake-side variable valve timing mechanism. The connection passage for guiding oil to the valve timing variable mechanism, which is operated by supplying oil having the same pressure, and in which the amount of oil leakage is large, of the exhaust side valve timing variable mechanism and the intake side valve timing variable mechanism is located downstream in the oil passage than the connection passage for guiding oil to the valve timing variable mechanism in which the amount of oil leakage is small.

According to the above configuration, the pressure of the oil introduced to the valve timing variable mechanism located on the downstream side of the oil passage becomes higher than that in the case where the connection passage for introducing the oil to the valve timing variable mechanism having a large amount of oil leakage is provided on the upstream side. Therefore, the hydraulic pressure shortage of the valve timing variable mechanism located on the downstream side of the oil passage can be suppressed.

In the above aspect, the internal combustion engine may further include: the timing chain is configured to be wound around the exhaust side cam sprocket, the intake side cam sprocket, and the crankshaft sprocket to transmit rotational torque. When the side where the valve timing variable mechanism with less oil leakage is provided is defined as the upstream side and the side where the valve timing variable mechanism with more oil leakage is provided is defined as the downstream side, the cam sprocket on the downstream side is located farther from the crank sprocket in the traveling direction of the timing chain than the cam sprocket on the upstream side.

According to the above configuration, the tension of the timing chain is stronger in the downstream cam sprocket where the oil leakage is large than in the upstream cam sprocket. Therefore, the cam sprocket, which is relatively easily worn out among the 2 cam sprockets, is easily lubricated by the oil leaked out from the valve timing variable mechanism.

In the above aspect, the internal combustion engine may further include an oil control valve that is connected to each of the exhaust side valve timing variable mechanism and the intake side valve timing variable mechanism and controls supply and discharge of oil. An oil control valve of a valve timing variable mechanism, which is at least highly leaked from oil, is inserted into a radial center portion of the corresponding valve timing variable mechanism.

When the oil control valve is inserted into the center of the valve timing variable mechanism, the responsiveness of the valve timing variable mechanism can be improved, but oil leakage is likely to occur. In the above configuration, the oil control valve is inserted at least in the center of the variable valve timing mechanism where oil leakage is large, and therefore, the oil leakage from the variable valve timing mechanism is of a corresponding amount. On the premise of such a configuration, it is preferable to arrange a connection passage for supplying oil to the variable valve timing mechanism having a large amount of oil leakage downstream of the variable valve timing mechanism having a small amount of oil leakage, in order to suppress a shortage of oil pressure in the oil passage.

In the above aspect, the internal combustion engine may further include an injection connection passage provided in the oil passage, partitioned inside the cylinder head, and guiding oil to an oil injection nozzle that injects oil. The injection connection passage is located upstream of the oil passage with respect to a connection passage that leads oil to the variable valve timing mechanism having a large amount of oil leakage in the exhaust side variable valve timing mechanism and the intake side variable valve timing mechanism.

Since oil is injected from the oil jet, when the oil pressure of the oil guided to the oil jet is low, there is a possibility that the oil cannot be injected well. According to the above configuration, the hydraulic pressure before the drop by the valve timing variable mechanism with a large amount of oil leakage can be supplied to the injection passage. Therefore, a sufficient oil pressure can be ensured as the oil pressure of the oil to be guided to the oil jet.

An internal combustion engine according to another aspect includes: a cylinder head; an exhaust-side camshaft assembled to the cylinder head; an intake side camshaft assembled to the cylinder head; an exhaust side valve timing variable mechanism that is attached to an end portion of the exhaust side camshaft and changes an opening and closing timing of an exhaust valve by supply and discharge of oil; an intake side valve timing variable mechanism that is attached to an end portion of the intake side camshaft and changes an opening and closing timing of an intake valve by supply and discharge of oil; an oil passage defined in the cylinder head and through which oil pumped by an oil pump flows; an exhaust-side connection passage connected to the oil passage, branched from the oil passage, and guiding oil to the exhaust-side variable valve timing mechanism; and an intake-side connecting passage connected to the oil passage, branched from the oil passage downstream of the exhaust-side connecting passage, and guiding oil to the intake-side variable valve timing mechanism. When the exhaust side valve timing variable mechanism and the intake side valve timing variable mechanism are operated by being supplied with oil having the same pressure, the amount of oil leakage from the intake side valve timing variable mechanism is larger than the amount of oil leakage from the exhaust side valve timing variable mechanism.

According to the above configuration, the pressure of the oil guided to the intake side valve timing variable mechanism located on the downstream side of the oil passage becomes higher than that in the case where the intake side connection passage for guiding the oil to the intake side valve timing variable mechanism having a large leakage of the oil is provided on the upstream side. Therefore, the hydraulic pressure shortage of the intake side valve timing variable mechanism located on the downstream side of the oil passage can be suppressed.

Drawings

Fig. 1 is a schematic side view of an internal combustion engine.

Fig. 2 is a schematic diagram of an internal combustion engine.

Fig. 3 is a plan view schematically showing the structure of the inside of the intake variable valve timing mechanism.

Fig. 4 is a view taken along line 4-4 in fig. 3, and is a cross-sectional view showing a state where the intake-side relative rotation phase is locked at the intermediate phase by the intermediate lock portion.

Fig. 5 is a cross-sectional view showing a state where the intake-side relative rotational phase is held at the most retarded phase.

Fig. 6 is a plan view schematically showing the internal structure of the exhaust valve timing variable mechanism.

Fig. 7 is a view taken along line 7-7 in fig. 6, and is a cross-sectional view showing a state in which the exhaust side relative rotation phase is held between the most retarded phase and the most advanced phase.

Fig. 8 is a graph showing changes in hydraulic pressure when the intake-side connecting passage is connected to the upstream side of the oil passage and the exhaust-side connecting passage is connected to the downstream side of the oil passage.

Fig. 9 is a graph showing changes in hydraulic pressure when the exhaust-side connection passage is connected to the upstream side of the oil passage and the intake-side connection passage is connected to the downstream side of the oil passage.

Detailed Description

An embodiment of an internal combustion engine will be described with reference to the accompanying drawings. In the following description, the internal combustion engine is mounted on a vehicle, and the vertical direction of the vehicle will be described as the vertical direction of the internal combustion engine.

First, a schematic configuration of an internal combustion engine E according to the present embodiment will be described with reference to fig. 1 and 2. As shown in fig. 1, the internal combustion engine E has a cylinder block CB having a rectangular parallelepiped shape as a whole. As shown in fig. 2, a plurality of cylinders C are partitioned inside the cylinder block CB. In fig. 2, only 1 cylinder C is illustrated. Inside each cylinder C, a piston 100 is housed so as to be capable of reciprocating inside the cylinder C. Piston 100 is coupled to crankshaft 10 via connecting rod 110.

As shown in fig. 1, a plurality of crank caps, not shown, are fixed to the lower end of the cylinder block CB. The crankshaft 10 is rotatably supported between the cylinder blocks CB and the crankshaft head. The crankshaft 10 penetrates the cylinder block CB, and both end portions of the crankshaft 10 protrude outside the cylinder block CB. A crankshaft sprocket 11 is fixed to the 1 st end in the axial direction of the crankshaft 10, i.e., the end on the near side of the drawing sheet in fig. 1. In fig. 1, the crankshaft sprocket 11 is schematically indicated by a circle.

A box-shaped oil pan 20 having a closed bottom is disposed at the lower end of the cylinder block CB so as to cover the crankshaft 10 from below. Oil for lubricating various parts of the internal combustion engine E and operating various mechanisms is contained in the oil pan 20. Further, an oil pump 21 for pressure-feeding the oil contained in the oil pan 20 is contained in the oil pan 20. An end portion of the input shaft 22 of the oil pump 21 protrudes to the outside of the internal combustion engine E. A substantially disk-shaped oil pump sprocket 23 is fixed to an end portion of the input shaft 22 of the oil pump 21. In fig. 1, the oil pump sprocket 23 is schematically indicated by a circle.

A pump chain PC is wound around the crankshaft sprocket 11 and the oil pump sprocket 23. Therefore, when the crankshaft 10 of the internal combustion engine E rotates, the rotational force is transmitted to the oil pump 21 via the crankshaft sprocket 11, the pump chain PC, and the oil pump sprocket 23.

A rectangular parallelepiped cylinder head CH is fixed to an upper end of the cylinder block CB. As shown in fig. 2, an exhaust port 30 and an intake port 40 are defined in the cylinder head CH. An exhaust pipe 31 for discharging exhaust gas from the exhaust passage 30 is connected to the exhaust passage 30. An intake pipe 41 for guiding intake air to the intake passage 40 is connected to the intake passage 40. A fuel injection valve 42 that injects fuel into the intake passage 40 is mounted on the intake pipe 41. Further, an ignition plug 50 for igniting fuel is mounted on the cylinder head CH at a position facing each cylinder C of the cylinder block CB.

A cam cap, not shown, is fixed to an upper end of the cylinder head CH. The exhaust-side camshaft 60 and the intake-side camshaft 70 are rotatably supported between the cylinder head CH and the cam caps. An exhaust cam 61 for converting the rotational motion of the exhaust camshaft 60 into a reciprocating linear motion is attached to the exhaust camshaft 60. Further, an intake cam 71 for converting the rotational motion of the intake camshaft 70 into a reciprocating linear motion is attached to the intake camshaft 70.

As shown in fig. 1, a direction orthogonal to both the vertical direction in the internal combustion engine E and the axial direction of the crankshaft 10, that is, the horizontal direction in fig. 1 is defined as the width direction of the internal combustion engine E. In this case, the exhaust camshaft 60 is positioned on the 1 st side, which is one side in the width direction, and the intake camshaft 70 is positioned on the 2 nd side, which is the other side in the width direction than the crankshaft 10, with respect to the center axis of the crankshaft 10. One end, i.e., the 1 st end, of the exhaust-side camshaft 60 and the intake-side camshaft 70 protrudes outward of the cylinder head CH. In addition, the exhaust side camshaft 60 and the intake side camshaft 70 extend in parallel with the center axis of the crankshaft 10.

As shown in fig. 2, in the cylinder head CH, an exhaust valve 32 for opening and closing the exhaust passage 30 and an intake valve 43 for opening and closing the intake passage 40 are mounted. The rotational motion of the exhaust side camshaft 60 is converted into a reciprocating linear motion via the exhaust cam 61 and the exhaust side drive lever 33 and transmitted to the exhaust valve 32. Likewise, the rotational motion of the intake side camshaft 70 is converted into reciprocating linear motion via the intake cam 71 and the intake side drive rod 44 and transmitted to the intake valve 43.

As shown in fig. 1, a substantially disk-shaped variable exhaust valve timing mechanism 600 is attached to the 1 st end of the exhaust camshaft 60, i.e., the end on the front side of the drawing sheet in fig. 1. A substantially cylindrical and bolt-type oil control valve 62 is inserted through a radially central portion of the exhaust side variable valve timing mechanism 600. A part of the tip end side of the oil control valve 62 is inserted into the exhaust side camshaft 60. Thereby, the exhaust side variable valve timing mechanism 600 is fixed to the exhaust side camshaft 60 by the oil control valve 62. The exhaust side variable valve timing mechanism 600 has an exhaust side cam sprocket 601. The exhaust-side variable valve timing mechanism 600 changes the opening and closing timing of the exhaust valve 32 by the supply and discharge of oil. In fig. 1, the exhaust cam sprocket 601 is schematically indicated by a circle.

An intake side variable valve timing mechanism 700 having a substantially disk shape is attached to the 1 st end portion of the intake side camshaft 70. A substantially cylindrical and bolt-type oil control valve 72 is inserted through a radially central portion of the intake-side variable valve timing mechanism 700. A part of the tip end side of the oil control valve 72 is inserted into the intake side camshaft 70. Thus, the intake side variable valve timing mechanism 700 is fixed to the intake side camshaft 70 by the oil control valve 72. The intake side variable valve timing mechanism 700 has an intake side cam sprocket 701. The intake-side valve timing variable mechanism 700 changes the opening and closing timing of the intake valve 43 by the supply and discharge of oil. In fig. 1, the intake side cam sprocket 701 is schematically indicated by a circle.

A cylinder head cover HC is fixed to an upper end of the cylinder head CH. The cylinder head cover HC covers most of the exhaust side camshaft 60, most of the intake side camshaft 70, and a plurality of cam caps, not shown, from above.

In the internal combustion engine E, a timing chain (timing chain) TC is wound around the crankshaft sprocket 11, the exhaust side cam sprocket 601, and the intake side cam sprocket 701. In the present embodiment, as shown in fig. 1, the crankshaft sprocket 11 rotates clockwise when viewed from the 1 st side in the axial direction of the crankshaft 10. The timing chain TC fed out from the crank sprocket 11 travels so as to return to the crank sprocket 11 again via the exhaust side cam sprocket 601 and the intake side cam sprocket 701.

A chain case 200 surrounding the timing chain TC and the pump chain PC is mounted on the outer surface of the 1 st side of the axial direction of the crankshaft 10 in the cylinder block CB. The chain case 200 is composed of a 1 st case 201 attached to the internal combustion engine E, and a 2 nd case, not shown, formed in a substantially same plan view shape as the 1 st case 201. The 1 st tank 201 and the 2 nd tank are disposed to face each other. Specifically, the end surface of the 2 nd tank is butted against the end surface of the 1 st tank 201 opposite to the internal combustion engine E. Between the 1 st and 2 nd tanks 201, a chain chamber R for accommodating a timing chain TC and a pump chain PC is defined.

The 1 st case 201 of the chain case 200 includes a plate-like main wall portion 202, and an outer edge wall portion 203 erected from an edge of the main wall portion 202 toward the 1 st side in the axial direction of the crankshaft 10. The plan view shape of the main wall portion 202 is designed according to the trajectories of the timing chain TC and the pump chain PC. In the present embodiment, the entire structure is long in the vertical direction, and the upper end reaches the cylinder head cover HC and the lower end reaches the oil pan 20. The 2 nd surface of the main wall portion 202 in the axial direction of the crankshaft 10 is fixed to the 1 st surface of the cylinder block CB in the axial direction of the crankshaft 10. The main wall portion 202 is provided with a notch or a hole through which the crank sprocket 11, the exhaust side cam sprocket 601, and the intake side cam sprocket 701 pass.

A fixed guide portion 210 for guiding the travel of the timing chain TC is fixed to the 1 st side surface of the main wall portion 202 of the 1 st case 201 in the axial direction of the crankshaft 10. The fixing guide portion 210 is located between the crankshaft sprocket 11 and the intake side cam sprocket 701. The fixing guide portion 210 has an elongated slightly curved shape, i.e., an arcuate shape. The outer side of the curve faces the widthwise center of the internal combustion engine E. The timing chain TC abuts against the curved outer side surface of the fixed guide portion 210. The fixing guide portions 210 are fixed to the cylinder block CB at upper and lower sides in the longitudinal direction thereof with bolts B.

A swing guide 220 for guiding the travel of the timing chain TC is fixed to the 1 st side surface of the main wall 202 of the 1 st case 201 in the axial direction of the crankshaft 10. The swing guide portion 220 is located between the crankshaft sprocket 11 and the exhaust side cam sprocket 601. The swing guide 220 has an elongated and curved shape, i.e., a bow shape. The outer side of the curve faces the widthwise center of the internal combustion engine E. That is, the outer side of the curve of the swing guide 220 faces the outer side of the curve of the fixing guide 210. A pin P is inserted into the swing guide 220 at the lower side in the longitudinal direction thereof. The swing guide 220 is attached to the cylinder block CB in a state of being swingable about the pin P. The timing chain TC abuts against the curved outer surface of the swing guide portion 220.

A tensioner 230 that swings the swing guide 220 by pressing the swing guide 220 is fixed to the main wall 202 of the 1 st case 201. The tensioner 230 is located on the 1 st side, which is the side closer to the timing chain TC wound around the crankshaft sprocket 11 and the exhaust cam sprocket 601 in the width direction of the internal combustion engine E. The tip end of the tensioner 230 abuts against the inside of the curve of the swing guide 220.

An oil jet 240 for injecting oil is opened on the 1 st surface of the cylinder head CH in the axial direction of the crankshaft 10. In the internal combustion engine E, the injection opening 241 of the oil jet 240 is disposed between the exhaust side cam sprocket 601 and the intake side cam sprocket 701 as viewed from the 1 st side in the axial direction of the crankshaft 10.

Next, the intake side valve timing variable mechanism 700 of the present embodiment will be described in detail with reference to fig. 3 to 5. As shown in fig. 3, the intake variable valve timing mechanism 700 has a substantially circular shape when viewed from the 1 st side in the axial direction of the intake camshaft 70. The intake-side valve timing variable mechanism 700 basically has a variable portion 710 that changes the valve timing, i.e., the opening and closing timing, of the intake valve 43, and an intermediate lock portion 740 that holds the valve timing of the intake valve 43 at an intermediate timing between the most retarded timing and the most advanced timing.

The housing rotor 715 of the variable portion 710 has a cylindrical portion 716 having a cylindrical shape as a whole. An intake side cam sprocket 701, which is an annular external gear sprocket, is fixed to an outer wall of the cylindrical portion 716 of the housing rotor 715. Further, the inner edge of the intake side cam sprocket 701 is fixed to the outer wall surface of the cylindrical portion 716. Therefore, the housing rotor 715 rotates integrally with the intake side cam sprocket 701. A plurality of (3 in the present embodiment) partition walls 717 protrude radially inward from the inner wall of the cylindrical portion 716. The protruding length of each partition wall 717 is the same. The partition walls 717 adjacent to each other in the circumferential direction partition the housing chamber 718. Further, a partition sealing portion 717S is provided at a tip end portion of the partition wall 717 on the protruding side.

A vane rotor 711 that rotates integrally with the intake camshaft 70 is disposed inside the housing rotor 715. A hub (boss)712 constituting a radially central portion of the vane rotor 711 is fixed to an end portion of the intake-side camshaft 70. A plurality of (3 in the present embodiment) blades 713 corresponding to the number of the above-described partition walls 717 protrude radially outward from the outer circumferential surface of the hub 712. The protruding length of each blade 713 is the same as that of the dividing wall 717. Each blade 713 is located between adjacent dividing walls 717 in the case rotor 715. Further, a blade seal portion 713S is provided at the tip end portion of the blade 713 on the projecting side to seal the gap between the blade 713 and the cylindrical portion 716. The partition sealing portion 717S of each partition wall 717 contacts the outer peripheral surface of the hub 712, and seals a gap between the hub 712 and each partition wall 717.

The housing chamber 718 of the housing rotor 715 is partitioned into 2 hydraulic chambers by the vanes 713 of the vane rotor 711 disposed radially inward of the housing rotor 715. The hydraulic chamber in the housing chamber 718 on the rear side in the rotation direction of the intake camshaft 70 than the vane 713 is an advance chamber 719 serving as an advance hydraulic chamber. The hydraulic chamber on the front side in the rotation direction of the intake side camshaft 70 with respect to the vane 713 in the housing chamber 718 is a retard chamber 720 as a hydraulic chamber for retarding.

As shown in fig. 4 and 5, the opening on one side of the housing rotor 715, i.e., the opening on the lower side in fig. 4, is closed by the 1 st cover 790. The opening on the other side of the housing rotor 715, i.e., the opening on the upper side in fig. 4, is closed by a 2 nd cover 791.

In the intake variable valve timing mechanism 700, when oil is supplied to the retard chambers 720 and oil is discharged from the advance chambers 719, the oil pressure in the retard chambers 720 becomes higher than the oil pressure in the advance chambers 719. In this case, the vane rotor 711 is relatively rotated with respect to the housing rotor 715 in a direction opposite to the rotation direction of the intake camshaft 70, i.e., in a left-hand direction in fig. 3. When the relative rotational phase of the vane rotor 711 with respect to the housing rotor 715 is thus displaced, the valve timing of the intake valve 43 with respect to the crankshaft 10 is retarded. In the following description, the "relative rotational phase of the intake camshaft 70 with respect to the crankshaft 10" is referred to as an "intake relative rotational phase".

When oil is supplied to the advance chamber 719 and discharged from the retard chamber 720, the oil pressure in the advance chamber 719 becomes higher than the oil pressure in the retard chamber 720. In this case, the vane rotor 711 is relatively rotated with respect to the housing rotor 715 in the rotation direction of the intake side camshaft 70 (rightward in fig. 3). When the intake side relative rotational phase is thus displaced, the valve timing of the intake valve 43 is advanced.

As shown in fig. 3, the intermediate locking portions 740 are provided to 2 of the blades 713 of the blade rotor 711. The intermediate lock 740 is a mechanism that holds the intake-side relative rotational phase at an intermediate phase set between the most retarded phase and the most advanced phase. Further, the most retarded phase refers to the relative rotational phase at which the valve timing is most retarded, and the most advanced phase refers to the relative rotational phase at which the valve timing is most advanced. In the state where the intake-side relative rotational phase is held at the intermediate phase, the valve timing of the intake valve 43 is held at an intermediate timing between the most retarded timing and the most advanced timing. Since the 2 intermediate locking portions 740 have the same configuration, one of them will not be described.

As shown in fig. 4 and 5, the intermediate locking portion 740 generally includes a pin movable portion 750 that projects and accommodates a pin for locking, and an intermediate locking hole 770 that fits a pin projecting from the pin movable portion 750. In the pin movable portion 750, an annular outer pin 752 is disposed on the outer periphery of an inner pin 751 formed in a cylindrical shape. The outer pin 752 is slidable relative to the inner pin 751 in the axial direction of the intake side camshaft 70, i.e., in the vertical direction in fig. 4. Also, the inner pins 751 and the outer pins 752 are received in receiving holes 753 formed in the blades 713.

In the housing hole 753, a cylindrical spring guide bush 754 is fixed to an opening portion of the housing hole 753 adjacent to the 2 nd cover 791, that is, an upper opening portion in fig. 4. The outer wall of the spring guide bush 754 comes into contact with the inner wall of the opening portion of the housing hole 753 adjacent to the 2 nd cover 791 to close the opening of the housing hole 753. In the housing hole 753, a cylindrical ring bushing 755 is fixed to an opening portion of the housing hole 753 adjacent to the 1 st cover 790, that is, an opening portion on the lower side in fig. 4. The outer wall of the ring bushing 755 contacts the inner wall of the opening portion of the housing hole 753 adjacent to the 1 st cover 790. A circular hole 756 is formed through the center of the ring bushing 755 to such an extent that the tip of the inner pin 751 can pass therethrough.

Further, an inner pin spring 757 is housed between the inner pin 751 and the spring guide bush 754. The inner pin spring 757 urges the inner pin 751 toward the 1 st cover 790. Further, an outer pin spring 758 is housed between the outer pin 752 and the spring guide bush 754. The outer pin spring 758 urges the outer pin 752 toward the 1 st lid 790.

A relief chamber 759 is defined between the outer pin 752 and the ring bushing 755. When the oil pressure in the release chamber 759 is increased by the supply of the oil to the release chamber 759, the outer pin 752 can be displaced toward the 2 nd cover 791 against the urging force of the outer pin spring 758. When the outer pin 752 is displaced toward the 2 nd cover 791, the inner pin 751 can be displaced toward the 2 nd cover 791 against the urging force of the inner pin spring 757.

The vane 713 defines an advance chamber communication passage 760. The advance chamber communication passage 760 communicates between the housing hole 753 and the advance chamber 719. The vane 713 defines a retard chamber communication passage 761. The retard chamber communication path 761 communicates with the housing hole 753 and the retard chamber 720. These advance chamber communication passage 760 and retard chamber communication passage 761 are provided at the following positions: the outer pin 752 is completely closed by the outer pin 752 when the outer pin 752 is located closest to the 2 nd cover 791, and is partially opened without being closed by the outer pin 752 when the outer pin 752 is located closest to the 1 st cover 790. Therefore, when the outer pin 752 is displaced toward the 2 nd cover 791, the communication between the advance chamber communication passage 760 and the retard chamber communication passage 761 is blocked by the outer pin 752. When the oil pressure in the release chamber 759 is reduced and the outer pin 752 is displaced toward the 1 st lid 790, the advance chamber 719 and the retard chamber 720 communicate with each other.

The intermediate locking hole 770 of the intermediate locking part 740 is recessed in a face adjacent to the pin movable part 750 in the 1 st cover 790. The middle locking hole 770 is cylindrical, and the diameter of the middle locking hole 770 is designed to be slightly larger than the diameter of the inner pin 751. The intermediate lock hole 770 is disposed at a position where the inner pin 751 of the pin movable portion 750 protrudes when the intake side rotation phase becomes the intermediate phase.

As shown in fig. 4, when the intake side rotation phase of the intermediate lock portion 740 reaches the intermediate phase, the inner pin 751 protrudes from the housing hole 753 toward the 1 st cover 790 by the biasing force of the inner pin spring 757. And into the intermediate locking aperture 770. In this way, the inner pin 751 engages with the intermediate lock hole 770 to restrict the relative rotation of the vane rotor 711 with respect to the housing rotor 715, and the intake-side relative rotation phase is locked to the intermediate phase.

As shown in fig. 3, an atmosphere opening passage 714 is defined in the vane rotor 711. The atmosphere opening passage 714 extends radially inward from the housing hole 753 of the blade 713, and opens to the inner wall of the hub 712. That is, the atmosphere opening passage 714 communicates the housing hole 753 of the vane 713 with the outside of the intake side valve timing variable mechanism 700 (the radially inner side of the vane rotor 711). The opening of the atmosphere opening passage 714 adjacent to the housing hole 753 is set to a position where the outer pin 752 is closed when the outer pin 752 is displaced toward the 2 nd cover 791. That is, when the outer pin 752 is displaced toward the 2 nd cover 791, the communication between the atmosphere opening passage 714 and the housing hole 753 is blocked by the outer pin 752. When the hydraulic pressure in the release chamber 759 is reduced and the outer pin 752 is displaced toward the 1 st cover 790, the atmosphere opening passage 714 and the housing hole 753 communicate with each other.

The oil sucked from the oil pan 20 by the oil pump 21 is supplied to various portions including the intake side variable valve timing mechanism 700 through the oil control valve 72 attached to the intake side variable valve timing mechanism 700. Although not shown, the oil control valve 72 is constituted by a housing having a plurality of ports, and a spool (spool) provided in the housing. In the present embodiment, the housing of the oil control valve 72 is formed by connecting a plurality of components in the axial direction.

An electromagnetic solenoid, not shown, is mounted on the oil control valve 72. The spool inside the housing is displaced in the axial direction based on the electromagnetic force of the electromagnetic solenoid and the urging force of the spring, thereby controlling the supply and discharge pattern of oil to and from the advance chamber 719, the retard chamber 720, and the release chamber 759.

The oil control valve 72 operates in any one of a plurality of operation modes by changing the supply/discharge state of oil in accordance with parameters such as the operating state of the internal combustion engine E. Examples of the operation mode of the oil control valve 72 include the following intermediate lock mode, oil filling mode, advance mode, hold mode, and retard mode.

In the intermediate lock mode, the supply and discharge of oil to and from the advance chamber 719 and the retard chamber 720 are stopped, and oil is discharged from the release chamber 759. In this case, since the hydraulic pressure in the release chamber 759 is low, the outer pin 752 is displaced toward the 1 st lid 790. Therefore, the inner pin 751 can protrude from the housing hole 753. Therefore, as shown in fig. 4, when the intake side relative rotational phase becomes the intermediate phase, the inner pin 751 engages with the intermediate lock hole 770, and the intake side relative rotational phase is locked in a state of being fixed to the intermediate phase. Further, since the outer pin 752 is displaced toward the 1 st cover 790, the atmosphere opening passage 714 and the housing hole 753 communicate with each other.

In the oil filling mode, oil is supplied to the advance chamber 719, while oil discharge from the retard chamber 720 is stopped and oil is discharged from the release chamber 759. In this case, since the hydraulic pressure in the release chamber 759 is low, the outer pin 752 is displaced toward the 1 st lid 790. Therefore, the advance chamber 719 and the retard chamber 720 communicate with each other, and oil supplied to the advance chamber 719 flows into the retard chamber 720. Therefore, the advance chamber 719 and the retard chamber 720 are quickly filled with oil, and therefore the intake side variable valve timing mechanism 700 is quickly brought into an operable state. Further, since the outer pin 752 is displaced toward the 1 st cover 790, the atmosphere opening passage 714 and the housing hole 753 communicate with each other. As a result, in the oil filling mode, a part of the oil supplied to the advance chamber 719 leaks to the outside through the atmosphere opening passage 714.

In the advance mode, oil is supplied to the advance chamber 719, oil is discharged from the retard chamber 720, and oil is supplied to the release chamber 759. In this case, since the hydraulic pressure in the advance chamber 719 becomes higher than the hydraulic pressure in the retard chamber 720, the intake-side relative rotational phase is displaced to the advance side, and the valve timing of the intake valve 43 is advanced. Since the hydraulic pressure in the release chamber 759 becomes high, the inner pin 751 is accommodated in the accommodation hole 753. Therefore, the intermediate locking portion 740 is unlocked from the intake-side relative rotational phase. Further, since the outer pin 752 is displaced toward the 2 nd cover 791 by increasing the hydraulic pressure in the release chamber 759, the atmosphere opening passage 714 and the housing hole 753 are blocked.

In the holding mode, the supply and discharge of oil to the advance chamber 719 and the retard chamber 720 are both stopped, and oil is supplied to the release chamber 759. In this case, the oil pressure of the oil in the advance chamber 719 and the retard chamber 720 does not change, and therefore the intake side relative rotational phase does not shift, and the valve timing of the intake valve 43 remains the current state. Since the hydraulic pressure in the release chamber 759 becomes high, the inner pin 751 is accommodated in the accommodation hole 753. Therefore, the intermediate lock portion 740 is unlocked from the relative rotational phase. That is, in the holding mode, unlike the lock mode, the intake side relative rotation phase is held by holding the hydraulic pressures of the advance chamber 719 and the retard chamber 720. Further, since the holding of the intake side relative rotational phase by the inner pin 751 is released, when switching to the advance mode or the retard mode described later, the vane 713 is rapidly rotated relatively, and the valve timing is rapidly changed. Further, for example, when the valve timing is held during engine operation, the holding mode is selected when the valve timing is released from the state locked by the intermediate locking portion 740. Further, since the outer pin 752 is displaced toward the 2 nd cover 791 by increasing the hydraulic pressure in the release chamber 759, the atmosphere opening passage 714 and the housing hole 753 are blocked.

In the retard mode, oil is supplied to the retard chamber 720, oil is discharged from the advance chamber 719, and oil is supplied to the release chamber 759. In this case, since the hydraulic pressure of the retard chamber 720 becomes higher than the hydraulic pressure of the advance chamber 719, the intake side relative rotation phase is displaced to the retard side, and the valve timing of the intake valve 43 is retarded. Since the hydraulic pressure in the release chamber 759 becomes high, the inner pin 751 is accommodated in the accommodation hole 753. Therefore, the intermediate locking portion 740 is unlocked from the intake-side relative rotational phase. Further, the retard mode is selected, for example, when retarding the valve timing. Further, since the outer pin 752 is displaced toward the 2 nd cover 791 by increasing the hydraulic pressure in the release chamber 759, the atmosphere opening passage 714 and the housing hole 753 are blocked.

Next, the exhaust side valve timing variable mechanism 600 of the present embodiment will be described in detail with reference to fig. 6 and 7. As shown in fig. 6, the exhaust variable valve timing mechanism 600 has a substantially circular shape when viewed from the 1 st side in the axial direction of the exhaust camshaft 60. The exhaust side variable valve timing mechanism 600 basically has a variable portion 710 that changes the valve timing (opening and closing timing) of the exhaust valve 32 and a lock portion 620 that holds the valve timing of the intake valve 43 at the most retarded timing. Since the configuration of the variable portion 710 is the same as that of the variable portion 710 of the intake variable valve timing mechanism 700, the same reference numerals are given thereto, and detailed description thereof is omitted. However, the cam sprocket attached to the variable portion 710 of the exhaust variable valve timing mechanism 600 will be referred to as the exhaust cam sprocket 601.

In the exhaust variable valve timing mechanism 600, when oil is supplied to the retard chamber 720 and discharged from the advance chamber 719, the oil pressure in the retard chamber 720 becomes higher than the oil pressure in the advance chamber 719. In this case, the vane rotor 711 rotates relative to the housing rotor 715 in a direction opposite to the rotation direction of the exhaust-side camshaft 60 (left-handed rotation in fig. 6). When the relative rotational phase of the vane rotor 711 with respect to the housing rotor 715 is thus displaced, the valve timing of the exhaust valve 32 with respect to the crankshaft 10 is retarded. In the following description, the "relative rotational phase of the exhaust side camshaft 60 with respect to the crankshaft 10" is referred to as "exhaust side relative rotational phase".

As shown in fig. 6, the locking portions 620 are provided to 1 of the blades 713 of the blade rotor 711. The locking portion 620 holds the exhaust-side relative rotation phase at the most retarded phase.

As shown in fig. 7, an opening of one side of the housing rotor 715, that is, an opening of a lower side in fig. 7 is closed by the 1 st cover 790. The opening of the other side of the housing rotor 715, i.e., the opening of the upper side in fig. 7, is closed by a 2 nd cover 791.

In the locking portion 620, a cylindrical accommodation hole 622 is recessed in a surface of the blade 713 adjacent to the 2 nd cover 791. The receiving hole 622 receives a locking pin 621. The locking pin 621 generally has a large diameter portion 629 and a small diameter portion 630. The large-diameter portion 629 is arranged to face the 2 nd cover 791, and has a cylindrical shape having substantially the same diameter as the inner diameter of the housing hole 622. The small diameter portion 630 protrudes from a surface of the large diameter portion 629 facing the 1 st cover 790 toward the 1 st cover 790. The small diameter portion 630 is cylindrical having a diameter smaller than the large diameter portion 629. A lock spring 625 for biasing the lock pin 621 toward the 1 st cover 790 is housed between a surface of the large diameter portion 629 adjacent to the 2 nd cover 791 and an inner wall of the 2 nd cover 791. A through hole 628 through which the small diameter portion 630 of the locking pin 621 passes penetrates is formed in a wall portion of the housing hole 622 adjacent to the 1 st cover 790.

In the locking portion 620, a release chamber 624 is defined by the lower surface of the large diameter portion 629, the side surface of the small diameter portion 630, and the inner wall of the housing hole 622. The vane 713 defines a retard communication passage 626 for communicating the release chamber 624 with the retard chamber 720. Further, a concave portion 631 that is recessed toward the 2 nd cover 791 is recessed in a surface of the blade 713 that faces the 1 st cover 790. An advance communication passage 627 for communicating the through hole 628 with the advance chamber 719 is defined by the concave portion 631 and the inner wall of the 1 st cover 790.

The lock pin 621 operates in a direction protruding from the vane 713 or in a direction retracting into the vane 713 based on a relationship between the oil pressure of the release chamber 624 and the force of the lock spring 625. The oil pressure of the release chamber 624 acts on the lock pin 621 in the direction of pulling in the blade 713. The force of the lock spring 625 acts on the lock pin 621 in a direction protruding from the blade 713.

On the inner wall of the 1 st cover 790, a locking hole 623 is concavely provided. The locking hole 623 is cylindrical, and the diameter of the locking hole 623 is designed to be slightly larger than the diameter of the locking pin 621. The lock hole 623 is disposed at a position where the lock pin 621 protruding from the vane 713 engages when the exhaust-side relative rotation phase reaches the most retarded phase.

The oil sucked from the oil pan 20 by the oil pump 21 is supplied to various portions including the exhaust side valve timing variable mechanism 600 through the oil control valve 62 attached to the exhaust side valve timing variable mechanism 600. The oil control valve 62 has the same configuration as the oil control valve 72 attached to the exhaust side variable valve timing mechanism 600, and therefore, the details thereof are omitted. The oil control valve 62 attached to the exhaust side variable valve timing mechanism 600 operates in any one of a plurality of operation modes by changing the supply/discharge state of oil in accordance with parameters such as the operating state of the internal combustion engine E. Examples of the operation mode of the oil control valve 62 include an advance mode, a hold mode, and a retard mode as described below.

In the advance mode, oil is supplied to the advance chamber 719 and the advance communication passage 627, and oil is discharged from the retard chamber 720 and the retard communication passage 626. In this case, since the hydraulic pressure in the advance chamber 719 becomes higher than the hydraulic pressure in the retard chamber 720, the exhaust side relative rotation phase is displaced to the advance side, and the valve timing of the exhaust valve 32 is advanced. When the oil in the retard chamber 720 is discharged, the oil is also discharged from the retard communication passage 626 and the release chamber 624, which communicate with the retard chamber 720. Also, when the oil is discharged from the release chamber 624, the locking pin 621 can be displaced toward the 1 st cover 790.

In the retard mode, oil is discharged from the advance chamber 719 and the advance communication passage 627, and oil is supplied to the retard chamber 720 and the retard communication passage 626. In this case, since the hydraulic pressure of the retard chamber 720 becomes higher than the hydraulic pressure of the advance chamber 719, the exhaust side relative rotation phase is displaced to the retard side, and the valve timing of the exhaust valve 32 is retarded. When oil is supplied to the retard chamber 720, oil is also supplied to the retard communication passage 626 and the release chamber 624 that communicate with the retard chamber 720. When oil is supplied to the release chamber 624, the lock pin 621 is displaced toward the 2 nd cover 791.

In the holding mode, the supply and drainage of oil to the advance chamber 719 and the retard chamber 720 are stopped. In this case, the oil pressures of the advance chamber 719 and the retard chamber 720 do not change, and therefore the exhaust side relative rotational phase does not shift, and the valve timing of the exhaust valve 32 remains the current state.

As shown in fig. 1, in the internal combustion engine E, an oil passage 130 through which oil pumped by the oil pump 21 flows is connected to the oil pump 21. The oil passage 130 is constituted by a tubular passage (piping) and a passage defined in the cylinder block CB and the cylinder head CH, and is only schematically illustrated in fig. 1. The upstream end of the oil passage 130 is connected to the oil pump 21, and the downstream end communicates with the inside of the oil pan 20.

An exhaust-side connection passage 131 for guiding oil to the exhaust-side variable valve timing mechanism 600 is connected to an intermediate portion of the oil passage 130. The exhaust-side connection passage 131 branches from the oil passage 130. The 1 st end of the exhaust side connection passage 131 is connected to the oil passage 130, and the 2 nd end of the exhaust side connection passage 131 is connected to the oil control valve 62 of the exhaust side variable valve timing mechanism 600. Further, an injection connection passage 132 for guiding oil to an oil injection nozzle 240 for injecting oil is connected to the oil passage 130. The injection connection passage 132 branches from the oil passage 130 on the downstream side of the branch point between the oil passage 130 and the exhaust-side connection passage 131 in the oil passage 130. The 1 st end of the injection connection passage 132 is connected to the oil passage 130, and the 2 nd end of the injection connection passage 132 is connected to the oil jet 240. Further, an intake side connection passage 133 for guiding the oil to the intake side valve timing variable mechanism 700 is connected to the oil passage 130. The intake-side connection passage 133 branches from the oil passage 130 on the downstream side of the branching point between the oil passage 130 and the injection connection passage 132 in the oil passage 130. The 1 st end of the intake side connection passage 133 is connected to the oil passage 130, and the 2 nd end of the intake side connection passage 133 is connected to the oil control valve 72 of the intake side variable valve timing mechanism 700.

The operation and effect of the present embodiment will be described. First, the difference in the ease of oil leakage between the intake variable valve timing mechanism 700 and the exhaust variable valve timing mechanism 600 will be described.

In the intermediate lock mode of the intake variable valve timing mechanism 700, when the inner pin 751 and the intermediate lock hole 770 are engaged, the inner pin 751 and the intermediate lock hole 770 collide with each other, and a collision sound may be generated. In the above embodiment, in order to prevent the collision sound, oil is supplied between the inner pin 751 and the intermediate lock hole 770. In the intermediate lock mode, the atmosphere opening passage 714 and the housing hole 753 communicate with each other. Therefore, when the inner pin 751 is engaged with the intermediate lock hole 770, the oil accumulated in the intermediate lock hole 770 leaks from the atmosphere open passage 714 to the outside of the intake variable valve timing mechanism 700 through the gaps between the respective portions of the intermediate lock portion 740.

For example, when an engine stall occurs, the internal combustion engine E may be stopped with the intake-side relative rotational phase held at the retard side of the intermediate phase. In this situation, the intake variable valve timing mechanism 700 is controlled to the intermediate lock mode for restarting the internal combustion engine E. At this time, although details are omitted, the spring provided in the intake variable valve timing mechanism 700 exerts an elastic force on the vane rotor 711 toward the intermediate position, and therefore the intake relative rotational phase shifts to the intermediate phase. In the intermediate lock mode, since the supply and discharge of oil are stopped, the hydraulic pressure in the release chamber 759 is reduced, and the outer pin 752 is displaced toward the 1 st lid 790. When the outer pin 752 is displaced toward the 1 st cover 790, the advance chamber 719 and the retard chamber 720 communicate with the atmosphere opening passage 714. Air is drawn into the advance chamber 719 from outside the intake side variable valve timing mechanism 700 via the atmosphere opening passage 714. The rotation of the vane rotor 711 to the advance side is promoted by the air being drawn into the advance chamber 719. In addition, oil remains in the retard chamber 720. The retard chamber 720 discharges oil to the outside of the intake side variable valve timing mechanism 700 via the atmosphere open passage 714. The vane rotor 711 is accelerated to rotate to the advance side by discharging the remaining oil from the retard chamber 720. Therefore, for example, when the engine is controlled to the intermediate lock mode for restarting the internal combustion engine E after an engine stall has occurred, oil leaks to the outside of the intake variable valve timing mechanism 700 in order to make the intake relative rotation phase the intermediate phase faster.

Further, in the intake side valve timing variable mechanism 700, the oil filling mode can be selected. In the oil filling mode, the atmosphere opening passage 714 and the advance chamber 719 communicate with each other via the housing hole 753. Therefore, when oil continues to be supplied to the advance chamber 719, oil leaks to the outside of the intake variable valve timing mechanism 700 through the atmosphere opening passage 714.

As described above, in the intake side variable valve timing mechanism 700, the intermediate lock mode and the oil filling mode, which cannot be selected in the exhaust side variable valve timing mechanism 600, can be selected. In the intermediate lock mode, as described above, when the engine is restarted and the inner pin 751 is engaged with the intermediate lock hole 770, oil is discharged to the outside of the intake side variable valve timing mechanism 700. That is, in the present embodiment, when oil of the same pressure is supplied to and operated by the exhaust variable valve timing mechanism 600 and the intake variable valve timing mechanism 700, the amount of oil leakage from the intake variable valve timing mechanism 700 is larger than the amount of oil leakage from the exhaust variable valve timing mechanism 600.

In the present embodiment, as the oil control valve for controlling the supply and discharge of oil to and from the intake variable valve timing mechanism 700, a bolt-type oil control valve 72 inserted through the center portion of the intake variable valve timing mechanism 700 is used. Since the oil control valve 72 can be disposed very close to the intake variable valve timing mechanism 700, the path through which oil is supplied from the oil control valve 72 to the intake variable valve timing mechanism 700 can be set short. Therefore, the response of the intake side valve timing variable mechanism 700 can be improved. When the interval between the housing and the spool in the oil control valve 72 is small, the spool may not slide smoothly. Therefore, the interval between the housing and the spool is set to be large accordingly. Therefore, when oil is supplied from the oil control valve 72, oil is likely to leak from the gap between the housing and the spool. Therefore, in the intake side variable valve timing mechanism 700 where oil originally leaks much, oil leaks from the bolt type oil control valve 72, and therefore, the entire oil leaks considerably.

Here, it is assumed that the intake-side connection passage 133 for guiding the oil to the intake-side valve timing variable mechanism 700 is connected from the upstream side to the downstream side of the oil passage 130 to the most upstream side. Next, the injection connection passage 132 for guiding the oil to the oil jet 240 is connected, and the exhaust side connection passage 131 for guiding the oil to the exhaust side variable valve timing mechanism 600 is connected on the most downstream side. In this case, as shown in fig. 8, the intake variable valve timing mechanism 700 located on the upstream side of the oil passage 130 has a large amount of oil leakage, and therefore the oil pressure is greatly reduced. Further, the oil pressure becomes very low at the oil jet 240 located downstream of the intake side variable valve timing mechanism 700. Therefore, the oil pressure required for the oil jet 240 to operate properly is lower. Further, since the oil pressure of the exhaust variable valve timing mechanism 600 located downstream of the oil jet 240 in the oil passage 130 is extremely low, the oil pressure is insufficient, and there is a possibility that the responsiveness of the exhaust variable valve timing mechanism 600 is lowered or the exhaust variable valve timing mechanism 600 cannot operate.

On the other hand, in the present embodiment, the exhaust-side connection passage 131 for guiding the oil to the exhaust-side variable valve timing mechanism 600 is connected from the upstream side to the downstream side of the oil passage 130 at the most upstream side. Next, the injection connection passage 132 for guiding the oil to the oil jet 240 is connected, and the intake side connection passage 133 for guiding the oil to the intake side valve timing variable mechanism 700 is connected to the most downstream side. In this case, as shown in fig. 9, in the exhaust side valve timing variable mechanism 600 located on the upstream side in the oil passage 130, oil leakage is less than in the intake side valve timing variable mechanism 700. Therefore, the decrease in the oil pressure is smaller than the amount of decrease in the oil pressure in the intake-side valve timing variable mechanism 700. Therefore, excessive decrease in the hydraulic pressure on the upstream side of the oil passage 130 can be suppressed. Therefore, a high oil pressure can be secured in the oil jet 240 located downstream of the exhaust side variable valve timing mechanism, and the oil jet 240 can be operated appropriately because the oil pressure exceeds the oil pressure required for the oil jet. Further, the intake side valve timing variable mechanism 700, which is located downstream of the oil jet 240 in the oil passage 130, is supplied with oil at a correspondingly high oil pressure. Therefore, the lack of the hydraulic pressure in the intake variable valve timing mechanism 700 located on the downstream side of the oil passage 130 can be suppressed, and therefore, the responsiveness of the intake variable valve timing mechanism 700 can be improved, and the possibility of the intake variable valve timing mechanism being inoperable can be suppressed. In particular, as described above, it is highly preferable to adopt the configuration of the oil passage 130 and the connection passages on the premise that the oil control valve 72 of the intake side variable valve timing mechanism 700 is of a bolt type.

In the present embodiment, the timing chain TC is fed out from the crank sprocket 11 in accordance with the clockwise rotation of the crank sprocket 11, and is returned to the crank sprocket 11 again via the exhaust side cam sprocket 601 and the intake side cam sprocket 701. Here, the timing chain TC is stretched between the intake side cam sprocket 701 and the crank sprocket 11 by the rotation of the crank sprocket 11, and therefore the tension of the timing chain TC increases. On the other hand, the timing chain TC is fed out between the crank sprocket 11 and the exhaust side cam sprocket 601 by the rotation of the crank sprocket 11, and therefore the tension of the timing chain TC is reduced. Therefore, the tension of the timing chain TC wound around the intake side cam sprocket 701 is greater than the tension of the timing chain TC wound around the exhaust side cam sprocket 601. Therefore, the friction between the intake side cam sprocket 701 and the timing chain TC is larger than the friction between the exhaust side cam sprocket 601 and the timing chain TC. That is, the intake side cam sprocket 701 is easily worn as compared with the exhaust side cam sprocket 601.

In the present embodiment, the intake cam sprocket 701 is provided in the intake valve timing variable mechanism 700 in which oil leaks more. The intake side cam sprocket 701 is located farther from the exhaust side cam sprocket 601 with respect to the crank sprocket 11 in the traveling direction of the timing chain TC. That is, the intake side cam sprocket 701 is located on the front side of the exhaust side cam sprocket 601 with respect to the crank sprocket 11 in the traveling direction of the timing chain TC. In other words, the crank sprocket 11, the exhaust side cam sprocket 601, and the intake side cam sprocket 701 are arranged in this order in the traveling direction of the timing chain TC. Oil leaking from the intake side valve timing variable mechanism 700 can reach the intake side cam sprocket 701. Therefore, the intake side cam sprocket 701, which is relatively easily worn, is easily lubricated by the oil leaked from the intake side valve timing variable mechanism 700. This enables oil leaking from the intake variable valve timing mechanism 700 to be effectively used. Accordingly, since large friction generated between the intake side cam sprocket 701 and the timing chain TC can be reduced, wear of the intake side cam sprocket 701 can be reduced.

The above embodiment can be implemented as modified as follows. This embodiment mode and the following modification examples can be implemented in combination with each other within a range not technically contradictory.

The intake side cam sprocket 701 may be located closer to the exhaust side cam sprocket 601 with respect to the crank sprocket 11 in the traveling direction of the timing chain TC. That is, the cam sprocket with a large leakage of oil may be located closer to the crankshaft sprocket 11 than the cam sprocket with a small leakage of oil.

The oil control valves 62, 72 need not be bolt-type valves inserted through the center portion of the valve timing variable mechanism. For example, the oil control valves 62 and 72 may be disposed in the cylinder head CH and the cylinder block CB, and these oil control valves 62 and 72 may be connected to the respective valve timing variable mechanisms via pipes. Further, as described above, the bolt type oil control valve has a large amount of oil leakage. Therefore, the valve timing variable mechanism using the bolt-type oil control valve is highly likely to be a valve timing variable mechanism in which oil leaks much when operating at the same oil pressure.

In the oil passage 130, the injection connecting passage 132 may be connected to the upstream side of the exhaust-side connecting passage 131. In addition to the injection connection passage 132, for example, a connection passage for guiding oil to an oil shower that supplies oil to the lash adjuster may be connected upstream of the oil passage 130 from the intake side connection passage 133. By connecting a connection passage such as the injection connection passage 132 at least upstream of the intake side connection passage 133, the hydraulic pressure shortage in the injection connection passage 132 and the lash adjuster can be suppressed. Further, if the hydraulic pressure in the connection passage such as the injection connection passage 132 does not need to be high, there is no problem in connecting to the downstream side of the intake side connection passage 133.

The injection connection passage 132 may be connected to an oil supply pipe separately provided in the oil passage 130 so as not to supply oil from the oil passage 130 to the oil jet 240.

The number of the partition walls 717 can be changed as appropriate. For example, 2 or 4 may be used. Further, if the number of the dividing walls 717 is changed, the number of the blades 713 is also changed correspondingly.

The number of the intermediate lock portions 740 may be changed as appropriate in the intake-side valve timing variable mechanism 700. For example, only 1 of the 3 blades 713 may be provided, or all of the blades 713 may be provided.

The intake-side variable valve timing mechanism 700 may be a structure that cannot be controlled to the intermediate lock mode or the oil filling mode. Specifically, as the intake side valve timing variable mechanism 700, a mechanism having the same structure as the exhaust side valve timing variable mechanism 600 of the above-described embodiment may be employed.

The exhaust side variable valve timing mechanism 600 may be a structure that can be controlled to be in the intermediate lock mode or the oil filling mode. Specifically, as the exhaust side valve timing variable mechanism 600, a mechanism having the same structure as that of the intake side valve timing variable mechanism 700 of the above embodiment can be adopted.

Depending on the configurations of the exhaust side variable valve timing mechanism 600 and the intake side variable valve timing mechanism 700 and the types of valves used for the oil control valves of the respective variable valve timing mechanisms, there may be a case where the exhaust side variable valve timing mechanism 600 operates by supplying oil of the same oil pressure as the intake side variable valve timing mechanism 700 and oil leakage increases. In this case, the exhaust-side connection passage 131 of the exhaust-side variable valve timing mechanism 600 may be positioned upstream of the oil passage 130 from the intake-side connection passage 133 of the intake-side variable valve timing mechanism 700.

The exhaust side valve timing variable mechanism 600 and the intake side valve timing variable mechanism 700 may be of the same structure. Even in the case of the variable valve timing mechanisms having the same structure and the same specifications, the amount of oil leakage may vary due to manufacturing errors and the like. In such a case, the connection passage for supplying oil to the variable valve timing mechanism having a large amount of oil leakage may be located on the downstream side of the oil passage 130.

The configurations of the fixed guide 210, the swing guide 220, the tensioner 230, and the chain case 200 may be appropriately changed. For example, the position of the pin P fixing the swing guide 220 may be the longitudinal direction upper side. In addition, the position where the tensioner 230 abuts against the swing guide 220 may be the lower side in the longitudinal direction.

In the internal combustion engine E, the structures of the cylinder block CB, the oil pan 20, the cylinder head CH, and the cylinder head cover HC may be changed as appropriate. For example, the configuration of the cylinder head CH can be changed in accordance with the number of cylinders C of the cylinder block CB.