JP7255957B2 - automotive internal combustion engine - Google Patents

Description

The present invention relates to an internal combustion engine for automobiles.

When installing an internal combustion engine in the engine room of an automobile, for example, in a bonnetless type automobile where the engine room is located below the driver's seat, such as a one-box vehicle or a light truck, the cylinder bore should be placed at a large horizontal angle. is being done. That is, it is practiced to slant the cylinder bore to the horizontal side of the vertical line (for example, Patent Document 1).

Now, the oil used to lubricate the valve train and the oil used to drive the VVT flows down inside the cylinder head and returns to the oil pan through the oil drop holes provided in the cylinder head and cylinder block. In the case of a slant-type internal combustion engine in which the cylinder bore is tilted to the horizontal side, when the vehicle body turns (turns to the right), a phenomenon occurs in which the oil accumulated in the cylinder head is drawn toward the timing chain due to inertial force.

Therefore, even if the oil moves to the timing chain side during turning, it is necessary to have a means to return the oil to the oil pan (otherwise, the amount of oil in the oil pan will drop excessively and the oil strainer will suck in air). .).

Regarding this point, it is conceivable to provide a large number of oil pits, but in order to quickly return the oil that has been drawn to the side of the timing chain, the size of the oil pits must be considerably large. The strength of the head and cylinder block may be reduced, and there may be no space in the cylinder head and cylinder block to form a large diameter oil pit.

On the other hand, as a low-center-of-gravity engine for buses and passenger cars, for example, a horizontally opposed type in which the cylinder bore is laid horizontally is used. Therefore, a timing chain is used to rake the oil toward the oil pan. Patent Document 2 discloses that a rectifying plate that directs the flow of oil is provided in the middle of the oil flow path. It is

JP-A-11-241651 JP 2009-97398 A

The timing chain is covered by the front cover, but even in a slant type internal combustion engine, if a structure is adopted in which the timing chain scrapes oil toward the oil pan when turning, the timing chain placement space between the cylinder block and the front cover will be reduced. can be used as an oil return passage, the oil can be quickly returned to the oil pan even during turning without complicating the structure or reducing the strength of the member.

On the other hand, an internal combustion engine requires an oil strainer for sucking oil out of the oil pan, and the oil strainer must be arranged deep in the oil pan. In order to reduce the amount of oil used as much as possible, it is beneficial to partially form a deep portion in the oil pan, so the side near the timing chain is usually formed deep ( In the case of automotive internal combustion engines such as the horizontal front exhaust type, it is necessary to pass the exhaust pipe under the oil pan. There are circumstances that need to be shallow.).

Therefore, the oil strainer must be attached to the oil pan or the front cover on the side close to the timing chain, but it must be avoided that the attachment of the oil strainer obstructs the flow of oil.

The present invention has been made against the background of such a situation, and is intended to prevent rapid return of oil during turning in an internal combustion engine for automobiles in which the cylinder bore is laid so as to be greatly inclined to the horizontal side from the vertical line. To enable an oil strainer to be installed without any trouble.

The claimed invention is
"A cylinder block in which the cylinder bore axis is inclined to the horizontal side from the vertical line and which holds the crankshaft rotatably in a substantially horizontal posture, and a sprocket provided at the front end portion of the crankshaft protruding from the cylinder block. comprising a timing chain and a front cover covering the timing chain,
When the vehicle body turns, the oil accumulated in the cylinder head moves to the timing chain side, and the rotation of the timing chain sweeps the oil toward the oil pan.
It has a basic configuration.

In addition to the above basic configuration,
"A support rib to which an oil strainer is attached is formed on the oil pan or the front cover in such a manner as to block part of the oil that flows in due to the rotation of the timing chain, and the oil that has flowed into the support rib is is formed in the form of a through-hole through which the oil escapes to the oil pan.
configuration is added.

In the present invention, the timing chain arrangement space between the cylinder block and the front cover is used as an oil return passage when the vehicle body turns, and the timing chain is used as means for forcibly returning oil, which complicates the structure. The oil can be quickly returned to the oil pan during turning without reducing the strength of the cylinder head and the cylinder block.

Further, since the oil pan or the front cover is provided with the support ribs for the oil strainer on the timing chain side, the oil strainer can be securely mounted. Furthermore, since the support ribs have a reinforcing effect, they can contribute to improving the strength of the oil pan or the front cover.

Since the timing chain arrangement space is used as an oil flow path, the oil flowing down from the cylinder head changes its flow in the direction of the crank axis and flows into the oil pan. Since the part that attaches to the crankshaft has a long position in the direction of the crankshaft line, it is rational to place the support ribs in a position that protrudes in a direction that crosses the crankshaft line, and is positioned like a weir against the oil that flows into the oil pan. Yes, which allows the oil strainer to be easily and firmly attached to the support ribs.

Since the support ribs have oil passages in the form of through holes , there is no problem with the oil return function. Therefore, the oil strainer can be easily and firmly attached while quickly returning the oil during turning. Further, since the oil strainer is not so heavy, there is no problem in supporting strength of the oil strainer even if the support ribs are provided with oil passages in the form of through holes . Therefore, the weight of the oil pan or the front cover can be reduced without impairing the function of supporting the oil strainer. Therefore, it can contribute to improvement in fuel consumption.

Although it is possible to provide the support ribs on the front cover, if the support ribs are provided on the oil pan as in the embodiment, the oil strainer can be attached first, and then the front cover can be attached, so the oil pan and oil strainer are complicated. There is an advantage that the oil strainer can be easily attached even if the shape is small.

FIG. 2 is a front view of the upper half of the internal combustion engine with the front cover omitted; FIG. 2 is a front view of the lower half of the internal combustion engine with the front cover omitted; It is a bottom view in the state where the lower oil pan is omitted. It is a perspective view of an upper oil pan. It is a front view of an upper oil pan. FIG. 6 is a VI-VI view of FIG. 5; FIG. 7 is a cross-sectional view of the internal combustion engine viewed from the direction of VII-VII in FIGS. 5 and 6; FIG. 8 is a partially enlarged view of FIG. 7;

Next, embodiments of the present invention will be described based on the drawings. In the following description, terms such as front-rear, left-right, and up-down are used to specify directions. The front-rear direction is the direction of the crank axis, the left-right direction is the horizontal direction orthogonal to the crank axis direction, and the up-down direction is the vertical direction. . Regarding the front and rear, the side on which the timing chain is arranged is the front, and the side on which the transmission is arranged is the rear, in accordance with the general naming conventions used for internal combustion engines. Just to make sure, the directions are clearly indicated in each figure.

The direction of the cylinder axis in the cylinder block is called the top face, which faces the piston during the compression stroke, and the bottom face, which faces the piston during the expansion stroke. It is distinguished from the vertical direction, which is the direction.

(1) Outline of internal combustion engine This embodiment is applied to a four-cylinder internal combustion engine for automobiles. As shown in FIGS. 1 and 2, the internal combustion engine includes a cylinder block 1, a cylinder head 2 fixed to the top surface of the cylinder block 1, and a head cover 3 fixed to the top surface of the cylinder head 2 . It is a slant type internal combustion engine that lays on the horizontal side rather than the plumb line . The axis of the cylinder bore is inclined at an angle of slightly more than 60° with respect to the vertical line O1 and at an angle of slightly less than 30° with respect to the horizontal plane O2.

In this way, the cylinder bore axial center is slant so that it is closer to the horizontal than the vertical line. It is separated from the lower oil pan 5 fixed to. The upper oil pan 4 is an aluminum die-cast product, and the lower oil pan 5 is a sheet metal product.

As shown in FIG. 1, the cylinder head 2 has a two-layer structure consisting of a first portion 2a fixed to the cylinder block 1 and a second portion 2b fixed to the top surface of the first portion 2a. A pair of driven sprockets 7 with which a timing chain 6 meshes is rotatably held in the portion 2b. Note that the driven sprocket 7 is actually attached to the VVT device.

In FIGS. 1 and 2, the cylinder block 1, the cylinder head 2, and the oil pans 4 and 5 are hatched with parallel oblique lines in order to clarify their contours. Therefore, the hatched lines are not cross-sectional representations.

As shown in FIG. 2 , a crankshaft 9 is rotatably held at the bottom of the cylinder block 1 via a crankcap 8 . A front end portion of the crankshaft 9 is exposed in front of the cylinder block 1, and a driving sprocket 10 is fixed to the exposed portion as shown in FIG. A timing chain 6 is wound around the driving sprocket 10 and the driven sprocket 7 .

As shown in Figs. By fixing them, a space surrounded by the front cover 11, the cylinder block 1 and the upper oil pan 4 forms a timing chain arrangement space 12. As shown in FIG. 3 and 6, the front cover 11 is schematically shown.

In the internal combustion engine of this embodiment, the exhaust side is directed downward and the intake side is directed upward. As shown in FIGS. 1 and 2, the timing chain 6 is held in a posture with a narrow gap between an intake side guide (upper guide) 13 and an exhaust side guide (lower guide) 14 . The exhaust side guide 14 is fixed, and the intake side guide 13 is movable.

The internal combustion engine of this embodiment is mounted in the engine room vertically with the crankshaft 9 directed in the longitudinal direction of the vehicle body. Further, the front cover 11 is arranged in the engine room so as to be positioned on the front side of the vehicle body.

When the vehicle body turns to the right, the centrifugal force (inertial force) causes the oil that has flowed down to the cylinder head 2 to move toward the timing chain 6. Because it is installed in the middle or rear part, the oil does not flow into the oil drop hole when the vehicle body turns to the right, and the amount of oil in the oil pan may drop significantly.

Therefore, in the present embodiment, the inside of the cylinder head 2 and the timing chain arrangement space 12 are communicated with each other, so that the oil accumulated in the front part of the cylinder head 2 is discharged from the timing chain arrangement space 12 to the oil pan during right turning. 2, 7 and 8, the oil splashes from the end of the timing chain arrangement space 12 toward the oil pans 4 and 5 due to the scraping action of the timing chain 6. continue.

The upper oil pan 4 is devised so that the oil can be smoothly returned to the oil pans 4 and 5 when turning right. This point will be explained below.

(2) Basic Structure of Upper Oil Pan As can be understood from FIGS. It has a wall 18 and a pair of rear walls 19 connected to the rear ends of the upper and lower longitudinal side walls 16,17.

A baffle plate (bottom plate) 20 integrally connected to the upper and lower longitudinal side walls 16, 17 and the front and rear walls 18, 19 is integrally formed at the lower portion of the upper oil pan 4, and is indicated by parallel oblique lines in FIG. , a lower oil pan mounting surface 21 is formed so as to surround the baffle plate 20. As shown in FIG. A flange 5 a (see FIG. 2, for example) of the lower oil pan 5 is fixed to the lower oil pan mounting surface 21 . Since the upper surface of the upper oil pan 4 is horizontal, the lateral width of the upper longitudinal side wall 16 is large and the lateral width of the lower longitudinal side wall 17 is small.

As shown in FIGS. 4 and 5, the front wall 18 is formed with a front recess 22 for receiving the crank cap 8, and the rear wall 19 is formed with a rear recess 23 into which the bearing is fitted. Although it goes without saying, the transmission case is fixed in a state of straddling the rear surface of the cylinder block 1 and the rear surface of the upper oil pan 4 .

As shown in FIG. 6, at the top of the upper longitudinal side wall 16 and the lower longitudinal side wall 17 of the upper oil pan 4, a large number of inward bosses 24 for fixing to the cylinder block 1 are intermittently formed in the longitudinal direction. It is As shown in FIGS. 4 and 5, the upper longitudinal side wall 16 of the upper oil pan 5 is formed with a downward stepped portion 25 extending in the front-rear direction (crank axis direction). A baffle plate 20 is connected to the end.

As shown in FIGS. 3 and 6, the baffle plate 20 is formed with a left-right longitudinal first oil pit 26 located in the front portion thereof, and a plurality of circular second oil pits 27 dispersed around the periphery. It is The second oil pit 27 may have other shapes such as a square shape. As can be seen from FIG. 7 , the driving sprocket 10 is offset forward of the front wall 18. As shown in FIG. Therefore, the oil that has flowed through the timing chain arrangement space 12 changes its direction in the crank axial direction at a portion below the timing chain 6 as indicated by an arrow X in FIG. become.

The oil pump is arranged on the front cover 11, and the oil is sucked up by the oil pump from an oil strainer 28 shown in FIGS. The oil strainer 28 is composed of laterally extending pipes 28a extending left and right and downward pipes 28b connected to the ends thereof. It enters inside the lower oil pan 5 through the hole 29 . As shown in FIG. 7, the lower oil pan 5 has a deep front portion, and the downward pipe 28b of the oil strainer 28 is immersed in the deep portion.

In particular, as shown in FIGS. 4, 5 and 8, a support rib 30 overlapping the front cover 11 is integrally formed at the front and lower portion of the upper oil pan 4. The support rib 30 is provided with an oil strainer 28. A recess 31 is formed in which the base end of the transverse pipe 28a is tightly fitted. A proximal end portion of the horizontal pipe 28a is fixed to a support rib 30 with a screw.

Since the lateral pipe 28a of the oil strainer 28 is elongated in the front-rear direction, the support ribs 30 extend in the left-right direction orthogonal to the crank axis (extends in the direction parallel to the front cover 11). Therefore, the horizontal pipe 28a can be fitted into the recess 31 of the support rib 30 without difficulty, and the oil strainer 28 can be easily attached.

On the other hand, as shown in FIG. 5 , the portion of the upper oil pan 4 where the support ribs 30 are provided is the lowest in the front portion of the upper oil pan 4 . Therefore, as can be understood from FIG. 8, the support rib 30 acts as a plate that blocks the flow of part of the oil that has flowed down through the timing chain arrangement space 12 .

Therefore, as shown in FIGS. 5, 7 and 8, the support rib 30 is formed with an oil passage 32 in the form of a through hole for releasing the oil toward the lower oil pan 5 . In addition, since the oil passage 32 is positioned higher than the lower oil pan 5 and the baffle plate 20, the lower surface of the oil passage 32 is gradually expanded as shown in FIGS. It is formed on the inclined surface 32a approaching the baffle plate 20. As shown in FIG.

The inner surface of the portion of the front wall 18 of the upper oil pan 4 that extends from the support rib 30 to the baffle plate 20 is also formed into an inclined surface 33 that is inclined downward toward the lower oil pan 5 and the baffle plate 20 . . A recess 34 exists in the middle of the inclined surface 33, but this may be omitted.

To summarize the flow of oil when the vehicle body turns to the right, the oil that has vigorously flowed through the timing chain arrangement space 12 due to the scraping action of the timing chain 6 is discharged from the timing chain arrangement space 12, and then partially The oil jumps over the support rib 30 and enters the lower oil pan 5 from the first oil drop hole 26 of the baffle plate 20 toward the baffle plate 20.例文帳に追加Another portion of the oil scatters into the space surrounded by the support ribs 30 and the front cover 11, flows down from this space through the oil passages 32 toward the baffle plate 20, and reaches the first oil drop hole 26. flows into the inside of the lower oil pan 5.

Since the lower surface of the oil passage 32 is an inclined surface 32a and the inner surface of the front wall 18 is also an inclined surface 33 directed downward, the direction-changed oil can be quickly returned to the lower oil pan 5. can. As a result, the return effect of the oil is ensured, and the phenomenon of air sucking by the oil strainer 28 can be prevented.

For example, as shown in FIGS. 3 and 5, a receiving seat 36 to which an oil filter 35 is attached protrudes forward at the front and lower portion of the upper oil pan 4 . As shown in FIG. 4, an oil feed port 37 for flowing oil toward a receiving seat 36 and an oil return port for discharging purified oil are provided on the top surface of the upper portion of the front wall 18 of the upper oil pan 4. Port 38 is open.

The oil pressure-fed by the oil pump flows from the oil passage formed in the front cover 11 to the oil passage formed in the cylinder block 1, and then flows from the oil passage formed in the cylinder block 1 to the oil in the upper oil pan 4. It flows into feed port 37 . Also, the oil discharged from the oil return port 38 is sent to the main gallery formed in the cylinder block 1 . Therefore, the oil feed port 37 and the oil return port 38 of the upper oil pan 4 communicate with the oil passage formed in the bottom surface of the cylinder block 1 and the main gallery.

2, part of the oil scraped out by the timing chain 6 scatters upward. hit and fall. Therefore, it is possible to prevent the timing chain 6 from being excessively wet with oil.

Although the embodiments of the present invention have been described above, the present invention can be embodied in various other ways.

The present invention can be embodied in a slant type internal combustion engine for automobiles. Therefore, it can be used industrially.

O1 vertical line O2 horizontal plane 1 cylinder block 2 cylinder head 4 upper oil pan 5 lower oil pan 6 timing chain 7, 10 sprocket 9 crankshaft 11 front cover 12 timing chain arrangement space 16 upper longitudinal side wall 17 lower longitudinal side wall 18 front wall 20 baffle Plate 26 First oil trap 27 Second oil trap 28 Oil strainer 28a Lateral pipe 28b Downward pipe 29 Strainer hole 30 Support rib 31 Recess 32 Oil passage 32a Inclined surface of oil passage 33 Inclined surface of front wall

Claims (1)

A cylinder block in which the cylinder bore axis is inclined to the horizontal side from the vertical line and the crankshaft is rotatably held in a substantially horizontal posture, and the timing of meshing with the sprocket provided at the front end portion of the crankshaft protruding from the cylinder block. comprising a chain and a front cover covering the timing chain,
An automotive internal combustion engine in which oil accumulated in a cylinder head moves toward the timing chain when a vehicle body turns, and the timing chain circulates to sweep the oil toward an oil pan,
A support rib to which an oil strainer is attached is formed on the oil pan or the front cover in such a manner as to block part of the oil that flows in due to the rotation of the timing chain. The oil passage that escapes to the oil pan is formed in the form of a through hole ,
Automotive internal combustion engine.

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