WO2023047868A1

WO2023047868A1 - Internal combustion engine

Info

Publication number: WO2023047868A1
Application number: PCT/JP2022/031664
Authority: WO
Inventors: 英幸安田; 裕貴徳丸
Original assignee: 三菱自動車工業株式会社
Priority date: 2021-09-24
Filing date: 2022-08-23
Publication date: 2023-03-30
Also published as: JPWO2023047868A1

Abstract

This internal combustion engine comprises a cylinder block that houses cylinders, a crankshaft rotatably supported by the cylinder block, a first balancer shaft extending parallel to the crankshaft, a first gear, a second gear, and a drive member that transmits power from the crankshaft to a shaft different from the crankshaft to drive the different shaft. The first gear is fixed to the first balancer shaft and receives power from the crankshaft. The second gear is disposed at the end of the first balancer shaft and drives a driven member. In the internal combustion engine, a cylinder block partition is disposed between the first gear and the second gear, the second gear and the driving member are arranged on a side of the partition opposite from the first gear with the partition therebetween, and the second gear and the drive member overlap in the extending direction of the crankshaft.

Description

internal combustion engine

This disclosure relates to internal combustion engines.

Conventionally, an internal combustion engine mounted on a vehicle is known. Some of such internal combustion engines include a balancer shaft for reducing vibrations of the internal combustion engine and a mechanical pump for increasing the pressure of the fuel (see, for example, Patent Document 1). The internal combustion engine of Patent Document 1 transmits the rotation of the crankshaft to the balancer shaft and the mechanical pump. A fuel pump gear is attached to the mechanical pump. The fuel pump gear is provided with a drive gear for driving the camshaft. A timing chain is wound around the drive gear. Rotation is transmitted to the camshaft by a timing chain that is wound around the drive gear.

Japanese Patent Application Laid-Open No. 2011-163252

In the internal combustion engine of Patent Document 1, the fuel pump gear and the drive gear are arranged side by side in the extension direction of the crankshaft (front-rear direction in Patent Document 1). As a result, the length in the extending direction of the crankshaft of the internal combustion engine is increased. An internal combustion engine mounted on a vehicle is preferably compact in the direction of the crankshaft.

An object of the present disclosure is to provide an internal combustion engine in which the extending direction of the crankshaft is compact.

An internal combustion engine according to the present disclosure includes a cylinder block that houses cylinders, a crankshaft that is rotatably supported by the cylinder block, a first balancer shaft that extends parallel to the crankshaft, a first gear, and a second gear. and a driving member for transmitting the power of the crankshaft to a shaft different from the crankshaft to drive the different shaft. A first gear is fixed to the first balancer shaft and receives power from the crankshaft. A second gear is disposed at the end of the first balancer shaft and drives the driven member. In the internal combustion engine, a cylinder block partition is arranged between the first gear and the second gear, the second gear and the driving member are arranged on the opposite side of the first gear and the partition, and the second gear and the driving member overlap each other in the extending direction of the crankshaft.

According to this configuration, the first gear that receives power from the crankshaft and drives the first balancer shaft is located inside the partition wall of the cylinder block, and the second gear that drives the driven member is located outside the cylinder block partition wall. In addition, the second gear and the drive member are arranged at overlapping positions in the extending direction of the crankshaft. Accordingly, it is not necessary to arrange the second gear and the driving member side by side in the extension direction of the crankshaft outside the partition wall of the cylinder block. As a result, it is possible to provide an internal combustion engine in which the extending direction of the crankshaft is compact.

According to the present disclosure, it is possible to provide an internal combustion engine in which the extending direction of the crankshaft is compact.

1 is a conceptual top view showing the arrangement of components of an internal combustion engine according to an embodiment of the present disclosure; FIG. FIG. 2 is a layout diagram of gears inside a cylinder block partition according to an embodiment of the present disclosure; FIG. 2 is a layout diagram of gears on the outside of a cylinder block partition wall according to an embodiment of the present disclosure; FIG. 4 illustrates the positional relationship of a first balancer gear with a fuel pump cam according to an embodiment of the present disclosure;

An embodiment of the present disclosure will be described below with reference to the drawings. In this specification and drawings, the direction in which the crankshaft 4 extends is referred to as the longitudinal direction Q of the internal combustion engine, the direction in which the cylinder C extends is referred to as the vertical direction G (upper side U), and the longitudinal direction Q and the vertical direction G are referred to. The orthogonal direction is referred to as a left-right direction P. In the front-rear direction Q, the front side F is on the timing chain 16 side, which will be described later. As for the left-right direction P, the right side R is the second balancer shaft side, which will be described later, and the left side is the opposite side, as viewed from the front side F of the internal combustion engine. Note that FIG. 1 is a conceptual top view showing each configuration for easy identification, and is different from an actual top view. For example, when viewed from above, the pump drive gear 22 is hidden behind the pump camshaft gear 24 and cannot be seen. Further, the counter gear 28 is hidden behind the second balancer shaft gear 26 when viewed from above.

As shown in FIG. 1, an internal combustion engine 1 includes a cylinder block 2, a crankshaft 4, a first balancer shaft 6, a second balancer shaft 8, a mechanical pump (an example of a driven member) 10, and a flywheel. a wheel 12; As shown in FIG. 3, the internal combustion engine 1 further includes a camshaft (an example of a shaft different from the crankshaft 4) 14, a timing chain (an example of an endless chain or belt) 16, and a chain tensioner (tension adjusting member). example) 18 and a cylinder head 19 . The internal combustion engine 1 of this embodiment is a diesel engine that directly injects fuel into the cylinder C. As shown in FIG. In such a diesel engine, a mechanical pump 10 pressurizes fuel supplied from a fuel tank (not shown).

1, 2 and 3, the internal combustion engine 1 includes a first balancer shaft gear (an example of a first gear) 20, a pump drive gear (an example of a second gear) 22, and a pump camshaft. A gear (an example of a third gear) 24, a second balancer shaft gear (an example of a fourth gear) 26, a counter gear (an example of a fifth gear) 28, and a crankshaft gear (an example of a sixth gear) 30 , and a chain sprocket (an example of a seventh gear) 32 .

As shown in FIG. 1, the cylinder block 2 accommodates a cylinder C in which a piston (not shown) slides. In this embodiment, the internal combustion engine 1 is a four-cylinder series arrangement in which four cylinders C are arranged in the front-to-rear direction Q, in order from the front, number 1 cylinder C1, number 2 cylinder C2, number 3 cylinder C3, and number 4 cylinder C4. be. As shown in FIGS. 1 and 2, the cylinder block 2 has a partition wall 2a and a skirt portion 2b.

The partition wall 2a is a wall that separates the chain case 2c in which the timing chain 16 is accommodated and the crankcase 2d in which the crankshaft 4 is accommodated. In this embodiment, the partition wall 2a functions as a front wall of the cylinder block 2, and a chain cover 2e that covers the timing chain 16 is fixed in front of the front wall in accordance with the shape of the front wall.

The skirt portion 2b is a portion of the cylinder block 2 that spreads in the left-right direction P from below the upper end of the cylinder C. The skirt portion 2b accommodates at least each pin and counterweight portion of the crankshaft 4 and at least weight portions of the first balancer shaft 6 and the second balancer shaft 8 .

The crankshaft 4 is rotatably supported by the cylinder block 2 via a plurality of bearing caps 4a. Specifically, a plurality of bearing caps 4a are secured to journal walls extending downward from between each cylinder C. As shown in FIG. The crankshaft 4 is rotatably supported between the journal wall and the bearing cap 4a via bearings so that the rotation axis X1 is parallel to the longitudinal direction Q. As shown in FIG. In this embodiment, five caps are arranged side by side in the front-rear direction Q so that the first bearing cap 4a is in the front row and the fifth bearing cap 4a is in the rearmost row. The crankshaft 4 is provided with journals numbered 1 to 5 so as to correspond to the bearing cap 4a. Further, in this embodiment, the rotation axis X1 of the crankshaft 4 is offset to the left with respect to the center X2 of the cylinder C, as shown in FIG. As a result, the rotation of the crankshaft 4 becomes smoother, and the first balancer shaft 6 can be placed closer to the right side. As a result, the mechanical pump 10 can be prevented from protruding leftward, the length of the internal combustion engine 1 in the left-right direction can be shortened, and the internal combustion engine 1 can be made compact.

As shown in FIG. 1, the front end of the crankshaft 4 protrudes forward from the partition wall 2a and a chain sprocket 32 is fixed thereto. The rear end of the crankshaft 4 protrudes rearward from the rear wall 2f of the cylinder block 2, and the flywheel 12 is fixed thereon. In this embodiment, a transmission (an example of a power transmission device) is attached to the rear end of the crankshaft 4 via a flywheel 12 . Note that the transmission may be an automatic transmission or a manual transmission. The transmission may also be a transmission or a transaxle with multiple speed reducers.

The crankshaft gear 30 is fixed to the outer circumference of the journal of the crankshaft 4 . Crankshaft gear 30 transmits power to first balancer shaft gear 20 and counter gear 28 . In this embodiment, the crankshaft gear 30 is provided behind the first journal. In other words, the crankshaft gear 30 is arranged on the opposite side of the chain sprocket 32 in the front-rear direction Q with the partition wall 2a interposed therebetween. As shown in FIG. 3, the No. 1 bearing cap 4a is fixed to a recess 2g provided in the lower portion of the partition wall 2a and functions as a part of the partition wall 2a separating the chain case 2c and the crankcase 2d.

As shown in FIG. 1, the first balancer shaft 6 extends parallel to the crankshaft 4. The first balancer shaft 6 has a weight portion 6a, and the first balancer shaft 6 rotates at twice the rotation speed of the crankshaft 4, thereby canceling vibrations generated by combustion in the internal combustion engine 1. . The first balancer shaft 6 is inserted through a through hole penetrating the journal wall and is rotatably supported by a plurality of bearings 6b. As shown in FIG. 2, in the present embodiment, the rotation axis X3 of the first balancer shaft 6 is offset to the left and above the rotation axis X1 of the crankshaft 4 . As a result, the length of the internal combustion engine 1 in the left-right direction can be reduced.

The first balancer shaft gear 20 is fixed to the outer circumference of the first balancer shaft 6 at a position overlapping the crankshaft gear 30 in the front-rear direction Q. The first balancer shaft gear 20 receives power from the crankshaft 4 by meshing with the crankshaft gear 30 . The gear ratio between the first balancer shaft gear 20 and the crankshaft gear 30 is 1:2, and the first balancer shaft 6 rotates at twice the rotational speed of the crankshaft 4 as described above.

As shown in FIG. 1 , the pump drive gear 22 is arranged at the front end of the first balancer shaft 6 . A partition wall 2 a is arranged between the first balancer shaft gear 20 and the pump drive gear 22 . Specifically, the partition wall 2a is provided with a through hole through which the front end portion of the first balancer shaft 6 can be inserted. The first balancer shaft 6 is inserted through the through hole while the first balancer shaft gear 20 is fixed. The partition wall 2a is arranged between the first balancer shaft gear 20 and the pump drive gear 22 by fixing the pump drive gear 22 while the front end portion of the first balancer shaft 6 is inserted through the through hole of the partition wall 2a. be done.

The pump drive gear 22 meshes with the pump camshaft gear 24 to drive the mechanical pump 10 . As shown in FIG. 3, the pump drive gear 22 may be provided with a balance hole (an example of a cavity) 22a. The balance hole 22a not only corrects the eccentricity of the pump drive gear 22, but may also function as a balancer.

The second balancer shaft 8 is arranged on the opposite side of the first balancer shaft 6 in the left-right direction P across the crankshaft 4 . Similarly to the first balancer shaft 6, the second balancer shaft 8 also has a weight portion 8b and rotates at twice the rotational speed of the crankshaft 4, thereby reducing the vibration generated by the combustion of the internal combustion engine 1. cancel out.

The second balancer shaft gear 26 is fixed to the outer periphery of the second balancer shaft 8 at a position overlapping the crankshaft gear 30 in the front-rear direction Q. The counter gear 28 is also arranged at a position overlapping the crankshaft gear 30 in the front-rear direction Q. As shown in FIG. The counter gear 28 transmits power in the counter-rotational direction of the crankshaft 4 to the second balancer shaft gear 26 . The second balancer shaft gear 26 transmits power in the counter-rotational direction of the crankshaft 4 to the second balancer shaft 8 via the counter gear 28 .

As shown in FIG. 2, in this embodiment, the rotation axis X4 of the second balancer shaft 8 is offset to the upper side and to the right of the rotation axis X1 of the crankshaft 4. Further, the rotation axis X4 of the second balancer shaft 8 is arranged above the rotation axis X3 of the first balancer shaft 6 . The second balancer shaft 8 is arranged on the right side of the cylinder C offset to the left side of the crankshaft 4 . As a result, the counter gear 28 can be arranged at a position overlapping the second balancer shaft gear 26 and the crankshaft gear 30 in the vertical direction, and the counter gear 28 can be arranged without protruding in the left-right direction P of the internal combustion engine 1 . As a result, the width of the internal combustion engine 1 in the left-right direction P can be suppressed.

The mechanical pump 10 is a pump for increasing the pressure of the fluid. As shown in FIG. 1 , the mechanical pump 10 is arranged on the side of the cylinder block 2 on the left side of the internal combustion engine 1 . As shown in FIG. 4, the mechanical pump 10 of this embodiment is a plunger fuel pump having a pump camshaft 10a, a pump cylinder 10b, a tappet 10c, and a pump cam 10d. A pump cam 10d is fixed to the pump cam shaft 10a and moves a tappet 10c up and down within the pump cylinder 10b. The mechanical pump 10 of this embodiment supplies fuel from a fuel tank to the pump cylinder 10b, and pressurizes the fuel by the tappet 10c to pressurize the fuel. The pressurized fuel is supplied to the injector via a pressure accumulator (common rail).

The pump camshaft gear 24 is fixed to the front end of the pump camshaft 10a and drives the mechanical pump 10. The pump camshaft gear 24 is arranged at a position overlapping the pump drive gear 22 in the front-rear direction Q. As shown in FIG. As shown in FIG. 3, the rotation axis X5 of the pump camshaft 10a is arranged above the rotation axis X3 of the first balancer shaft 6. As shown in FIG. As a result, the length of the internal combustion engine 1 in the left-right direction can be suppressed. Furthermore, as shown in FIG. 4, the rear surface of the first balancer shaft gear 20 is arranged behind the rear end surface of the tappet 10c. This makes it easy to dispose the mechanical pump 10 above the first balancer shaft gear 20 while suppressing the axial length of the pump camshaft 10a.

As shown in FIG. 3, the camshaft 14 is rotatably supported by the cylinder head 19. The camshaft 14 of this embodiment is an intake camshaft that drives the intake valves. However, camshaft 14 may be an exhaust camshaft that drives an exhaust valve. A cam sprocket 14 a is fixed to the front end of the cam shaft 14 . The endless timing chain 16 is wound around the chain sprocket 32 and the cam sprocket 14a. Chain sprocket 32 transmits power from crankshaft 4 to timing chain 16 . The timing chain 16 transmits power obtained from the chain sprocket 32 to the cam sprocket 14a. Cam sprocket 14 a drives cam shaft 14 . The chain tensioner 18 elastically supports the chain guide 18a in the pushing direction. The chain guide 18a is arranged at a position where it contacts the timing chain 16. As shown in FIG. The chain tensioner 18 adjusts the tension of the timing chain 16 by pressing the chain guide 18a against the timing chain 16. As shown in FIG.

As shown in FIG. 1, the pump drive gear 22 and the timing chain 16 are arranged on the opposite side of the first balancer shaft gear 20 with respect to the partition wall 2a. are placed in overlapping positions. As a result, the timing chain 16 can be arranged without protruding forward, and the length of the internal combustion engine 1 in the longitudinal direction Q can be made compact.

Furthermore, as shown in FIG. 3, the chain tensioner 18 is arranged at a position overlapping the second balancer shaft gear 26 when viewed from the front. Specifically, as shown in FIG. 1, the space inside the chain case 2c located in front of the second balancer shaft gear 26 is empty. By disposing the chain tensioner 18 in this space, the space in the longitudinal direction Q can be used without waste. As a result, the lengths of the internal combustion engine 1 in the longitudinal direction Q and the lateral direction P can be suppressed.

Also, the first balancer shaft gear 20, the second balancer shaft gear 26, the counter gear 28, and the crankshaft gear 30 are arranged in a space surrounded by the skirt portion 2b and the partition wall 2a. In other words, the first balancer shaft gear 20, the second balancer shaft gear 26, the counter gear 28, and the crankshaft gear 30 are arranged inside the crankcase 2d. On the other hand, the pump drive gear 22, the pump camshaft gear 24, the timing chain 16, and the chain sprocket 32 are arranged on the opposite side of the first balancer shaft gear 20 across the partition wall 2a. In other words, the pump drive gear 22, the pump camshaft gear 24, the timing chain 16, and the chain sprocket 32 are arranged in the space inside the chain case 2c. Thus, by arranging the gears in the space inside the crankcase 2d without waste, the timing chain 16, the chain tensioner 18 and the gears can be arranged in a row in the space inside the chain case 2c. As a result, the length of the internal combustion engine 1 in the front-rear direction Q can be suppressed, and a compact internal combustion engine 1 can be provided.

As described above, according to the present disclosure, it is possible to provide the internal combustion engine 1 that is compact in the longitudinal direction Q.

<Other embodiments>
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and various modifications are possible without departing from the gist of the invention. In particular, multiple modifications described herein can be arbitrarily combined as required.

(a) In the above embodiment, the internal combustion engine 1 is a diesel engine, but the present disclosure is not limited to this. The internal combustion engine 1 may be a gasoline engine or a hydrogen engine.

(b) In the above embodiment, the mechanical pump 10 was described as an example of the driven member, but the present disclosure is not limited to this. The driven member may be a fuel pump that pressurizes and raises the pressure of fuel, or a mechanical pump that pressurizes a fluid such as cooling water or oil, or a gas such as hydrogen. Further, the driven member may be auxiliary equipment of the internal combustion engine 1 such as an air conditioner compressor and a generator (alternator).

(c) In the above embodiment, the camshaft 14 is used as an example of a shaft different from the crankshaft 4, and the camshaft 14 is driven by a drive member. However, the present disclosure is limited to this. not to be The shaft different from the crankshaft 4 may be, for example, the shaft of a mechanical supercharger (for example, a supercharger) attached to the internal combustion engine 1 or any other shaft that obtains power from the crankshaft 4 . Further, in the above embodiment, the timing chain 16 is used as an example of the drive member, but the present disclosure is not limited to this. The drive member may be a timing belt or other belt or chain.

This application is based on a Japanese patent application (Japanese Patent Application No. 2021-155185) filed on September 24, 2021, the content of which is incorporated herein by reference.

1: internal combustion engine, 2: cylinder block 2a: bulkhead, 2b: skirt portion, 4: crankshaft 6: first balancer shaft, 8: second balancer shaft 10: mechanical pump, 14: camshaft 16: timing chain, 18: Chain tensioner 20: First balancer shaft gear (an example of first gear)
22: Pump drive gear (an example of the second gear)
22a: balance hole (an example of a cavity)
24: Pump camshaft gear (an example of the third gear)
26: Second balancer shaft gear (an example of the fourth gear)
28: Counter gear (an example of the fifth gear)
30: Crankshaft gear (an example of the sixth gear)
32: Chain sprocket (an example of the seventh gear)
C, C1, C2, C3, C4: cylinder

Claims

a cylinder block that houses the cylinder;
a crankshaft rotatably supported by the cylinder block;
a first balancer shaft extending parallel to the crankshaft;
a first gear fixed to the first balancer shaft and powered by the crankshaft;
a second gear disposed at the end of the first balancer shaft for driving a driven member;
a driving member that transmits the power of the crankshaft to a shaft different from the crankshaft to drive the different shaft;
with
A partition wall of the cylinder block is arranged between the first gear and the second gear,
The second gear and the drive member are arranged on opposite sides of the first gear with the partition wall interposed therebetween, and are arranged at a position where the second gear and the drive member overlap in the extending direction of the crankshaft. to be
internal combustion engine.
further comprising a third gear to which power is transmitted from the second gear to drive the driven member;
The third gear is arranged at a position overlapping the drive member in the extending direction of the crankshaft,
2. Internal combustion engine according to claim 1.
The drive member is an endless chain or belt,
a tension adjusting member for adjusting the tension of the chain or belt;
a second balancer shaft disposed on the opposite side of the first balancer shaft with respect to the crankshaft;
a fourth gear that transmits power in the counter-rotational direction of the crankshaft to the second balancer shaft;
further comprising
The tension adjusting member is arranged at a position where the fourth gear overlaps with the crankshaft when viewed from the end direction,
3. An internal combustion engine according to claim 1 or 2.
A power transmission device is attached to one end of the crankshaft,
the second gear and the drive member are arranged on the other side of the crankshaft;
An internal combustion engine as claimed in any one of claims 1 to 3.
a second balancer shaft disposed on the opposite side of the first balancer shaft with respect to the crankshaft;
a third gear to which power is transmitted from the second gear to drive the driven member;
a fourth gear that transmits power in the counter-rotational direction of the crankshaft to the second balancer shaft;
a fifth gear that transmits power in a counter-rotational direction of the crankshaft to the fourth gear;
a sixth gear fixed to the crankshaft and transmitting power from the crankshaft to the first gear and the fifth gear;
a seventh gear that is fixed to the crankshaft and transmits power from the crankshaft to the drive member;
The cylinder block has a skirt that spreads below the cylinder,
The first gear, the fourth gear, the fifth gear, and the sixth gear are arranged in a space surrounded by the skirt portion and the partition wall,
The second gear, the third gear, the drive member, and the seventh gear are arranged on the opposite side of the first gear across the partition wall.
An internal combustion engine as claimed in any one of claims 1 to 4.
The internal combustion engine according to any one of claims 1 to 5, wherein a part of the second gear has a cavity.