JP2020026737A - Internal combustion engine - Google Patents

Abstract

To provide an internal combustion engine capable of securing a suction amount of oil stored in an oil pan in turning a vehicle.SOLUTION: An internal combustion engine 10 is mounted in a vehicle in a manner that an extension direction of a crank shaft 21 is along a width direction of the vehicle. The internal combustion engine 10 includes a timing chain 23, a chain cover 17, an oil pump 40 disposed inside the chain cover 17, a strainer 47 disposed on the oil pan 14, and an oil return passage 16. The oil pump 40 has a communication groove along an axial direction of a rotating shaft to which power is input, on an inner peripheral surface of a rotor, and is constituted to return the oil to the oil pan 14 from an oil chamber of the oil pump 40. A suction port 48 formed on the strainer 47 and a discharge port 16 of the oil return passage 16 are disposed on a chain cover 17 side with respect to a center line C1.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an internal combustion engine.

  When the vehicle turns, the oil stored in the oil pan of the internal combustion engine may be biased by centrifugal force at the time of turning. At this time, if the suction port of the oil strainer provided in the oil pan is exposed from the oil level, air may be sucked from the suction port and the oil suction amount may be insufficient.

  In the oil strainer and the oil pump disclosed in Patent Literature 1, an opening of a return pipe connected to the oil pump is arranged near an intake port of the oil strainer in order to secure an intake amount of the oil when the oil is offset. Thus, the oil refluxed from the oil pump via the return pipe is sucked from the suction port of the oil strainer.

JP 2000-179319 A

  In the oil pump disclosed in Patent Literature 1, it is necessary to arrange the return pipe so that the recirculated oil is sucked again. Further, it is necessary to set an excess discharge amount for recirculating the oil via the return pipe. There has been a demand for a configuration that can ensure the amount of oil suctioned from the oil pan to the oil strainer during turning of the vehicle without returning the oil through the return pipe.

  An internal combustion engine for solving the above-mentioned problem is an internal combustion engine mounted on a vehicle such that an extension direction of a crankshaft is along a width direction of the vehicle, and transmits rotational power between the crankshaft and a camshaft. A timing chain, a chain cover attached to the cylinder block at one end side in the extension direction of the crankshaft and covering the timing chain, an oil pan for storing oil as lubricating oil for the internal combustion engine, and a partition in the pump housing. An oil chamber, a rotating shaft to which power is input, and a rotor that rotates integrally with the rotating shaft, and an oil pump disposed inside the chain cover; A suction pipe for supplying stored oil to the oil pump, and an oil pan in the suction pipe. A strainer attached to an end of the cylinder block, and an oil return passage provided in the cylinder block and returning oil to the oil pan. At least one of the rotating shaft and the rotor has a communication groove along the axial direction of the rotating shaft, a gap between the pump housing and the rotor in the axial direction of the rotating shaft, the communication groove, The oil in the oil chamber can be returned to the oil pan through the oil pan, and a suction port opened to the strainer and a discharge port of the oil return passage extend the crankshaft. The gist is that the cylinder block is provided closer to the chain cover than the center position of the cylinder block in the direction.

  When a vehicle on which an internal combustion engine is mounted turns, for example, to the side opposite to the side where the chain cover is arranged, the oil stored in the oil pan is biased toward the chain cover due to centrifugal force at the time of turning. In this case, in the above configuration, the suction port of the strainer is provided closer to the chain cover than the center position, so that the suction port is less likely to be exposed from the oil level. Thereby, it is possible to suppress the air from being sucked from the suction port of the strainer, and it is possible to secure the oil suction amount.

  On the other hand, when the vehicle turns to the side where the chain cover is disposed, the oil is biased to the opposite side to the side where the chain cover is disposed due to the centrifugal force at the time of turning. In the above configuration, the discharge port of the oil return passage is provided closer to the chain cover than the center position. Therefore, the oil that has passed through the oil return passage is returned to the chain cover side. For this reason, even if the oil is biased to the side opposite to the side where the chain cover is arranged due to centrifugal force, the oil on the chain cover side is easily secured. That is, the shortage of oil on the chain cover side due to the offset of the oil can be compensated by the oil returned from the oil return passage to the oil pan. Thus, it is possible to suppress the suction port of the strainer from being exposed from the oil level, and it is possible to secure the amount of oil suction from the suction port.

  Further, when the rotor of the oil pump is pressed against one of the rotating shafts in the axial direction by the centrifugal force at the time of turning of the vehicle, the gap between the rotor and the pump housing is increased on the turning direction side. This makes it easier for oil to leak from the oil chamber to the gap. In the above configuration, there is a communication groove capable of returning the oil in the oil chamber to the oil pan. That is, the oil can be returned from the oil chamber of the oil pump to the oil pan via the gap and the communication groove. Since such an oil pump is disposed inside the chain cover, oil leaked from the oil pump is returned to the chain cover. In this way, the oil leaked from the oil pump can also compensate for the shortage of oil on the chain cover side due to the offset of the oil. Thus, it is possible to suppress the suction port of the strainer from being exposed from the oil level, and it is possible to secure the amount of oil suction from the suction port.

  That is, according to the above configuration, when the oil is offset due to the centrifugal force at the time of turning, it is possible to secure the amount of oil suction from the inlet of the strainer regardless of the turning direction. Since it is possible to suppress the air from being suctioned from the suction port of the strainer, it is possible to suppress an increase in the bubble ratio of the oil due to the suction of the air.

FIG. 1 is a schematic diagram showing an embodiment of an internal combustion engine. Sectional drawing of the oil pump which the internal combustion engine concerning the embodiment has. The front view which looked at the internal combustion engine concerning the embodiment from the oil pan side. Sectional drawing of the chain tensioner which the internal combustion engine concerning the embodiment has.

Hereinafter, an embodiment of an internal combustion engine will be described with reference to FIGS.
FIG. 1 shows an internal combustion engine 10. The internal combustion engine 10 includes a crankshaft 21 that is a drive shaft. The crankshaft 21 extends in the left-right direction in FIG. The crankshaft 21 is housed in the crankcase 11. The internal combustion engine 10 includes a camshaft 22 that opens and closes an intake valve and an exhaust valve of the internal combustion engine 10. Although not shown in FIG. 1, the internal combustion engine 10 includes an intake camshaft 22 that drives an intake valve and an exhaust camshaft 22 that drives an exhaust valve. The intake valve and the exhaust valve are provided on the cylinder head 13.

  The internal combustion engine 10 is mounted on the vehicle such that the extension direction of the crankshaft 21 is along the width direction of the vehicle. FIG. 1 shows arrows indicating the vehicle width direction, which is the width direction of the vehicle when the internal combustion engine 10 is mounted on the vehicle, and vertically upward and vertically downward.

  The internal combustion engine 10 includes a timing chain 23 that transmits rotational power. The timing chain 23 is wound around a sprocket attached to the crankshaft 21 and a variable valve mechanism 24 described later. The internal combustion engine 10 includes a chain cover 17 that covers the timing chain 23. The chain cover 17 is attached to the cylinder block 12. The space covered by the chain cover 17 communicates with the inside of the crankcase 11. The bottom surface on the vertically lower side of the chain cover 17 has an inclined portion that is inclined vertically closer to the cylinder block 12.

  The internal combustion engine 10 includes a variable valve mechanism 24 (hereinafter, referred to as “VVT 24”) that changes the relative rotation angle of the camshaft 22 with respect to the rotation angle of the crankshaft 21. The VVT 24 is provided on each of the intake-side camshaft 22 and the exhaust-side camshaft 22. The VVT 24 has a built-in oil control valve 25 (hereinafter, referred to as “OCV 25”) for controlling the supply and discharge of oil to and from the VVT 24. The OCV 25 has a spool valve that can be displaced in the axial direction of the camshaft 22, and a sleeve that houses the spool valve. In the OCV 25, five modes are set as oil supply / discharge modes. Further, a predetermined clearance is set between the spool valve and the sleeve. The clearance is set to a size that allows oil to leak from the OCV 25.

An oil pan 14 for storing oil as lubricating oil for the internal combustion engine 10 is attached vertically below the crankcase 11.
The internal combustion engine 10 includes an oil pump 40 for supplying oil stored in the oil pan 14 to each part of the internal combustion engine 10. The oil pump 40 is disposed inside the chain cover 17. Note that the chain cover 17 forms a part of the housing of the oil pump 40.

  The oil pump 40 will be described with reference to FIG. The oil pump 40 has a rotating shaft 42 to which power is transmitted from the crankshaft 21. FIG. 2 shows an axis C <b> 2 along the center axis of the rotation shaft 42. The oil pump 40 is an internal gear type oil pump including an inner rotor 43 and an outer rotor 45. The inner rotor 43 and the outer rotor 45 are housed in the pump housing 41. The inner rotor 43 is a rotor that rotates integrally with the rotating shaft 42. The outer rotor 45 rotates with the rotation of the inner rotor 43. Due to the rotation of the inner rotor 43 and the outer rotor 45, the volume of the oil chamber 44 formed between the inner rotor 43 and the outer rotor 45 varies. In the oil pump 40, suction and discharge of oil are performed by changing the volume of the oil chamber 44.

  In the oil pump 40, a clearance is set between the inner rotor 43 and the outer rotor 45 and the pump housing 41 so as not to hinder the rotation of the inner rotor 43 and the outer rotor 45 in the extending direction of the axis C2.

  A communication groove 43A is formed on the inner peripheral surface of the inner rotor 43. The communication groove 43A is formed as a groove having a specified depth in a direction orthogonal to the axis C2. The communication groove 43A is formed so as to communicate from one end to the other end of the inner rotor 43 in the extending direction of the axis C2.

  The oil discharged from the oil pump 40 is used for lubricating driving parts such as the timing chain 23, the camshaft 22, and the crankshaft 21, for example. The oil is supplied to an OCV 25 of a VVT 24 that operates using hydraulic pressure, and a chain tensioner 30 described later. The oil supplied to each part of the internal combustion engine 10 is configured to return to the oil pan 14. For example, oil scattered from the timing chain 23, the OCV 25, the chain tensioner 30, the oil pump 40, and the like disposed in the chain cover 17 falls toward the bottom surface of the chain cover 17. The oil thus dropped is returned to the oil pan 14 via the bottom surface of the chain cover 17 or falls directly on the oil pan 14. Further, as shown in FIG. 1, an oil return passage 16 for guiding oil to an oil pan 14 is formed in the cylinder block 12. The oil return passage 16 extends in the vertical direction. A discharge port 16A for discharging oil is formed at the vertically lower end of the oil return passage 16.

  FIG. 1 shows a straight line passing through the center position of the cylinder block 12 in the direction in which the crankshaft 21 extends, and shows a center line C1 along the vertical direction. The discharge port 16A of the oil return passage 16 is disposed closer to the chain cover 17 than the center line C1.

  The oil in the oil pan 14 is sucked into the oil pump 40 through a suction pipe 49. A strainer 47 for removing foreign matter contained in oil sucked into the oil pump 40 is attached to an end of the suction pipe 49 on the oil pan 14 side. The strainer 47 is arranged inside the oil pan 14. The strainer 47 is provided with a suction port 48 for sucking oil. The suction port 48 opens toward the bottom of the oil pan 14. The strainer 47 is arranged such that the suction port 48 is located closer to the chain cover 17 than the center line C1.

  FIG. 3 shows the internal combustion engine 10 viewed from the bottom side of the oil pan 14. The oil pan 14 has an expansion part 15 bulging upward in FIG. The expansion portion 15 is formed so as to protrude so that the oil cover 14 has a larger oil storage capacity on the chain cover 17 side than the center line C1.

  As shown in FIGS. 1 and 4, the internal combustion engine 10 includes a chain tensioner 30 for adjusting the tension of the timing chain 23. A chain guide 51 for guiding the timing chain 23 is arranged in the chain cover 17. The chain tensioner 30 presses the chain guide 51 by changing the length of the protrusion 33. Thereby, the tension of the timing chain 23 is adjusted. The projecting length of the projecting portion 33 can be changed in the chain tensioner 30 by urging the projecting portion 33 by the spring 34 and hydraulic pressure acting on the projecting portion 33. FIG. 4 shows an arrow indicating the direction in which the protrusion 33 protrudes.

  The chain tensioner 30 has a protrusion 33 that abuts on the chain guide 51 and a tensioner housing 31 that houses the protrusion 33. The tensioner housing 31 is provided with an oil introduction gap 38 in which a part of the accommodation hole for accommodating the protrusion 33 is enlarged. In the range where the oil introduction gap 38 is formed, the inner peripheral surface of the tensioner housing 31 does not contact the outer peripheral surface of the protrusion 33. An oil introduction hole 37 is formed in the tensioner housing 31 so as to communicate with the oil introduction gap 38. Oil is introduced into the tensioner housing 31 through the oil introduction hole 37. An oil hole 39 communicating with the oil introduction gap 38 is formed in the protrusion 33. Oil is introduced into the protrusion 33 through the oil hole 39.

  In the chain tensioner 30, a hydraulic chamber 32 defined by the tensioner housing 31 and the projecting portion 33 is provided on the side opposite to the projecting direction of the projecting portion 33. The hydraulic chamber 32 is provided with a spring 34 for urging the projecting portion 33 in the projecting direction. The hydraulic chamber 32 is provided with a valve body 36 capable of closing a hole communicating the hydraulic chamber 32 and the inside of the protrusion 33. The valve body 36 is housed in a retainer 35 attached to the protrusion 33.

  A leakage groove 33 </ b> A is formed on the outer peripheral surface of the protrusion 33. The leakage groove 33 </ b> A is formed from one end to the other end of the protrusion 33 in the direction in which the protrusion 33 projects. The leakage groove 33A is formed as a groove having a depth that allows oil to leak from the hydraulic chamber 32 within a range that does not impair the function of the chain tensioner 30.

The operation and effect of the present embodiment will be described.
FIG. 1 shows the turning direction of the vehicle when the vehicle on which the internal combustion engine 10 is mounted turns. The left direction in FIG. 1 is displayed as a first direction TL, and the right direction as a second direction TR. Hereinafter, the “chain cover 17 side from the center line C1” is referred to as the TCC side. The “opposite side of the chain cover 17 with respect to the center line C1” is referred to as an anti-TCC side.

  When the vehicle equipped with the internal combustion engine 10 turns in the first direction TL, the oil stored in the oil pan 14 is biased toward the TCC due to the centrifugal force at the time of turning. In FIG. 1, the oil level at this time is indicated by a broken line as a first liquid level SL.

  In the internal combustion engine 10, the intake port 48 of the strainer 47 is provided on the TCC side. For this reason, when the vehicle turns in the first direction TL and the oil is shifted to the TCC side, the first liquid surface SL tends to be vertically higher than the suction port 48 as shown in FIG. That is, the suction port 48 is hardly exposed from the oil level. Thereby, it is possible to suppress the air from being sucked from the suction port 48 of the strainer 47, and it is possible to secure the oil suction amount.

  On the other hand, when the vehicle turns in the second direction TR, the oil is biased toward the anti-TCC side by the centrifugal force at the time of turning. In FIG. 1, the oil level at this time is indicated by a two-dot chain line as a second liquid level SR. The second liquid level SR tends to be vertically lower than the suction port 48 of the strainer 47 arranged on the TCC side. That is, the suction port 48 is easily exposed from the oil level. In this regard, in the internal combustion engine 10, the discharge port 16A of the oil return passage 16 is provided on the TCC side. Therefore, the oil that has passed through the oil return passage 16 is returned to the TCC side. Since the oil is easily returned to the TCC side of the oil pan 14, even if the oil is biased to the anti-TCC side by the centrifugal force at the time of turning in the second direction TR, the oil on the TCC side is easily secured. That is, when the vehicle turns in the second direction TR, the shortage of oil on the TCC side due to the bias of the oil toward the anti-TCC side can be compensated for by the oil returned from the oil return passage 16 to the oil pan 14. Thereby, it is possible to prevent the suction port 48 of the strainer 47 from being exposed from the oil level, and it is possible to secure the amount of oil suction from the suction port 48.

  When the vehicle turns in the second direction TR, the inner rotor 43 and the outer rotor 45 of the oil pump 40 are pressed against the pump housing 41 by the centrifugal force at the time of turning. FIG. 2 illustrates a centrifugal force CF acting on the inner rotor 43. When the centrifugal force CF acts in this manner, the clearance between the pump housing 41 and the inner rotor 43 and the outer rotor 45 increases in one direction. FIG. 2 shows the gap with the increased clearance as the gap D1. Here, in the oil pump 40, a communication groove 43A is formed in the inner rotor 43. When the gap D1 and the communication groove 43A communicate with each other, a leakage path through which oil can leak from the oil chamber 44 is formed. In addition, even if an oil seal that suppresses oil leakage from the oil pump 40 is provided, the leakage path including the gap D1 and the communication groove 43A can leak oil so as to avoid the oil seal. Since the oil pump 40 is disposed inside the chain cover 17, oil leaked from the oil pump 40 is returned to the TCC side. As described above, even with the oil leaking from the oil pump 40, the shortage of the oil on the TCC side due to the bias of the oil toward the anti-TCC side when the vehicle turns in the second direction TR can be compensated. Thereby, it is possible to prevent the suction port 48 of the strainer 47 from being exposed from the oil level, and it is possible to secure the amount of oil suction from the suction port 48.

  Further, in the internal combustion engine 10, oil leaked from the OCV 25 of the VVT 24 is returned to the TCC side. In addition, since the leakage groove 33A is provided in the chain tensioner 30, oil easily leaks through the leakage groove 33A. Then, the oil leaked from the chain tensioner 30 is returned to the TCC side. As described above, in the internal combustion engine 10, the oil is easily returned to the TCC side. Accordingly, when the vehicle turns in the second direction TR, it is possible to prevent the suction port 48 of the strainer 47 from being exposed from the oil level, and to secure the amount of oil suction from the suction port 48.

  In addition, since the oil pan 14 has the expansion portion 15, the volume capable of storing the oil is larger on the TCC side. In the oil pan 14, more oil can be stored on the TCC side. Therefore, even if the vehicle turns in the second direction TR and the oil is offset to the anti-TCC side, the oil on the TCC side is easily secured. Accordingly, when the vehicle turns in the second direction TR, it is possible to prevent the suction port 48 of the strainer 47 from being exposed from the oil level, and to secure the amount of oil suction from the suction port 48.

  As described above, according to the internal combustion engine 10, when the oil is offset due to the centrifugal force at the time of turning, it is possible to secure the amount of oil to be sucked from the inlet 48 of the strainer 47 regardless of the turning direction. Since the suction of air from the suction port 48 of the strainer 47 can be suppressed, an increase in the bubble rate of oil due to the suction of air can be suppressed.

This embodiment can be implemented with the following modifications. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
In the above embodiment, when the vehicle equipped with the internal combustion engine 10 turns in the first direction TL, the chain cover 17 is provided on the side where the oil is biased by the centrifugal force at the time of turning. When the vehicle turns in the second direction TR, the chain cover 17 may be provided on the side where the oil is offset. That is, the chain cover 17 may be provided on the left side in FIG. Also in this case, the strainer 47 is arranged such that the suction port 48 is located closer to the chain cover 17 than the center line C1, and the oil return passage 16 is positioned such that the discharge port 16A is located closer to the chain cover 17 than the center line C1. By providing the same, the same effect as the above embodiment can be obtained.

  In the above embodiment, the communication groove 43A is formed in the inner rotor 43, but a groove capable of forming a leakage path by communicating with the gap D1 may be provided in the rotating shaft 42. Further, a groove can be formed in the inner rotor 43 and the rotating shaft 42.

-A plurality of communication grooves 43A may be formed in the inner rotor 43.
In the above embodiment, the leakage groove 33 </ b> A is formed on the outer peripheral surface of the protruding portion 33. Further, grooves may be formed on the outer peripheral surface of the protrusion 33 and the inner peripheral surface of the tensioner housing 31.

  In the above embodiment, the leakage groove 33A is formed from one end to the other end of the protrusion 33. The leakage groove 33 </ b> A may be provided in a part of the protrusion 33. For example, the leakage groove may be formed only in the range from the hydraulic chamber 32 to the oil hole 39. Also in this case, it is easy to cause the oil to leak from the hydraulic chamber 32 through the leak groove.

  The shape of the oil pan 14 is not limited to the shape illustrated in FIG. 3 as long as the volume capable of storing oil is larger on the TCC side.

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Crankcase, 12 ... Cylinder block, 13 ... Cylinder head, 14 ... Oil pan, 15 ... Expansion part, 16 ... Passage, 16A ... Discharge port, 17 ... Chain cover, 21 ... Crankshaft, 22 ... Cam shaft, 23 ... Timing chain, 24 ... Variable valve mechanism (VVT), 25 ... Oil control valve (OCV), 30 ... Chain tensioner, 31 ... Tensioner housing, 32 ... Hydraulic chamber, 33 ... Protrusion, 33A ... Leakage groove, 34 ... spring, 35 ... retainer, 36 ... valve body, 37 ... oil introduction hole, 38 ... oil introduction gap, 39 ... oil hole, 40 ... oil pump, 41 ... pump housing, 42 ... rotating shaft, 43 ... Inner rotor, 43A: communication groove, 44: oil chamber, 45: outer rotor, 47: strainer, 48: suction , 49 ... intake pipe, 51 ... chain guide.

Claims (1)

An internal combustion engine mounted on the vehicle such that the extension direction of the crankshaft is along the width direction of the vehicle,
A timing chain for transmitting rotational power between the crankshaft and the camshaft,
A chain cover attached to the cylinder block on one end side in the extending direction of the crankshaft and covering the timing chain;
An oil pan for storing oil as lubricating oil for an internal combustion engine,
An oil chamber partitioned within a pump housing, a rotary shaft to which power is input, and a rotor that rotates integrally with the rotary shaft, and an oil pump disposed inside the chain cover. ,
A suction pipe for supplying oil stored in the oil pan to the oil pump,
A strainer attached to the oil pan side end of the suction pipe;
An oil return passage provided in the cylinder block and returning oil to the oil pan,
The oil pump has a communication groove along the axial direction of the rotating shaft on at least one of the rotating shaft and the rotor between the rotating shaft and the rotor, and the pump in the axial direction of the rotating shaft. It is configured to be able to return the oil in the oil chamber to the oil pan via a gap between the housing and the rotor, and the communication groove,
An internal combustion engine, wherein an intake port that opens to the strainer and a discharge port that the oil return passage has are provided closer to the chain cover than a center position of the cylinder block in a direction in which the crankshaft extends.