engine

Abstract

To provide an engine capable of realizing compactification.SOLUTION: An engine E of the present disclosure comprises: a crankcase 4 that supports the rotation of a crankshaft 2; a circulation pump 30 that circulates and pumps circulating liquid OL to a portion to be supplied in the crankcase 4; and an adjustment device 40 that is driven by the rotational force of the crankshaft 2, and adjusts the circulating liquid OL pumped by the circulation pump 30 to control a fluid-driven actuator 42. The adjustment device 40 is connected to a connection surface 44 of the crankcase 4 that faces an orthogonal direction PD.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to an engine having a regulator for controlling a fluid-powered actuator. [Background technology]

[0002] Patent Document 1 discloses an engine installed as a drive source for rotating an aircraft propeller. A drive device including this engine is provided with a flow control valve as an adjustment device for changing the pitch angle of the propeller. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 03-204395 Summary of the Invention [Problem to be solved by the invention]

[0004] A drive unit including an engine and an output shaft needs to be made smaller due to space limitations, etc. The adjustment device described above is connected to a cover, which increases the size of the cover and the overall size of the drive unit.

[0005] The disclosure of the present application provides an engine that can be made compact. [Means for solving the problem]

[0006] The engine of the present disclosure includes a crankcase that rotatably supports a crankshaft, a circulation pump that circulates and pressure-feeds circulating fluid to supply locations within the crankcase, and a regulating device that is driven by the rotational force of the crankshaft, regulates the circulating fluid pressure-fed by the circulation pump to generate hydraulic fluid, and controls fluid pressure-driven actuators with the hydraulic fluid. The regulating device is connected to a connecting surface formed on a wall surface of the crankcase that faces a direction perpendicular to both the axial direction of the crankshaft and the reciprocating direction of the pistons. [Effects of the Invention]

[0007] According to the engine of the present disclosure, the adjusting device is connected to the connecting surface of the crankcase, and the connecting surface is perpendicular to both the axial direction of the crankshaft and the reciprocating direction of the piston, which prevents the drive unit including the engine and output shaft from becoming large and allows for a compact design. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a side view showing an engine according to a first embodiment of the present disclosure. [Figure 2] FIG. [Figure 3] FIG. 2 is a side view of the engine as seen from the opposite side to FIG. [Figure 4] FIG. 2 is a longitudinal cross-sectional view showing the connection structure between the crankshaft and the output shaft of the engine. [Figure 5] FIG. 2 is a horizontal cross-sectional view showing the power transmission path of the governor of the engine. [Figure 6] FIG. 2 is a vertical cross-sectional view showing the oil inlet and outlet passages of the governor. DETAILED DESCRIPTION OF THE INVENTION

[0009] A preferred embodiment of the present disclosure will be described below with reference to FIGS. 1 to 6. The engine E of this embodiment is a reciprocating engine. For example, the engine of this embodiment is used in an airplane in which a propeller is disposed at the tip of the fuselage. In this case, the engine E is housed within the fuselage, and engine power is transmitted to the propeller. The use of the engine E is not limited to this, and it can also be used, for example, as a drive source for an airplane in which a propeller is disposed on a wing, or for a ship equipped with a propeller. In this embodiment, the propeller is equipped with a variable pitch mechanism that varies the pitch. The variable pitch mechanism is a fluid-driven actuator that varies the propeller pitch using the pressure of the hydraulic fluid introduced therein, in other words, fluid energy.

[0010] In the following description, the "width direction WD" refers to the direction in which the crankshaft 2 of the engine E extends, i.e., the direction of the axis AX1 of the crankshaft 2. In the width direction WD, the direction toward the width center is referred to as the "width inward" and the direction away from the width center is referred to as the "width outward." The "reciprocating direction VD" refers to the direction in which the pistons of the engine E reciprocate. The direction perpendicular to both the "width direction WD" and the "reciprocating direction VD" is referred to as the "perpendicular direction PD." In this embodiment, when the engine E is mounted on an airplane, the width direction WD is aligned with the longitudinal direction of the airplane's fuselage. When the airplane is in flight and the longitudinal direction is horizontal, the engine E is mounted with the reciprocating direction VD facing vertically, i.e., up and down.

[0011] The engine E is an in-line cylinder engine with multiple cylinders lined up in a row in the direction in which the crankshaft 2 extends. The engine E of this embodiment has six cylinders lined up in a row. However, the number of cylinders is not limited to this and may be, for example, four cylinders. Furthermore, although the engine E of this embodiment is a gasoline engine, the fuel is not limited to gasoline. The crankshaft 2 is formed in a crank shape, and converts the reciprocating motion of the piston 3, which occurs due to repeated combustion strokes, into rotational motion.

[0012] The engine E has a crankcase 4 that supports the crankshaft 2, a cylinder 6 that protrudes from the crankcase 4 in one direction in the reciprocating direction VD, and a cylinder head 8 that is connected to one protruding end of the cylinder 6 in the reciprocating direction. In the following description, the direction in which the cylinder 6 protrudes from the crankcase 4 in the reciprocating direction VD may be referred to as "upward," and the opposite side may be referred to as "downward."

[0013] The cylinder head 8 and the cylinder 6 form a combustion chamber 20. The cylinder head 8 is formed with an intake port 16, which is an intake passage that leads intake air to the combustion chamber 20, and an exhaust port 18, which is an exhaust passage that leads exhaust air to the outside of the combustion chamber 20. The cylinder head 8 is provided with a valve 21 for opening and closing the combustion chamber 20. The valve 21 includes an intake valve 21a that opens and closes the passage between the combustion chamber 20 and the intake port 16, and an exhaust valve 21b that opens and closes the passage between the combustion chamber 20 and the exhaust port 18. The intake valve 21a and the exhaust valve 21b are sometimes collectively referred to as intake and exhaust valves 21.

[0014] In this embodiment, an intake port 16 opens to one side (the right side in FIG. 1) of the cylinder head 8 in the orthogonal direction PD, and an exhaust port 18 opens to the other side (the left side in FIG. 1) in the orthogonal direction PD. In the following description, the intake port side in the orthogonal direction PD will be simply referred to as the "intake side," and the exhaust port side will be simply referred to as the "exhaust side."

[0015] The crankcase 4 is divided into two parts, a lower crankcase 4a and an upper crankcase 4b. In this embodiment, the upper crankcase 4b and the cylinder 6 are integrally formed by molding. However, the upper crankcase 4b and the cylinder 6 may be separate bodies. In the following description, the integrated crankcase upper 4b and the cylinder 6 are referred to as a cylinder block 10.

[0016] The engine E further has a head cover 12 connected to the upper end of the cylinder head 8. The cylinder head 8 and the cylinder head cover 12 form a cam chamber. A valve mechanism that opens and closes the intake and exhaust valves in conjunction with the rotation of the crankshaft 2 is disposed in the cam chamber.

[0017] The engine E also has an oil pan 14 connected to the lower end of the crankcase 4. The oil pan 14 stores engine oil OL, a type of circulating fluid that lubricates parts of the engine E that need to be lubricated and cools parts that need to be cooled. Examples of parts of the engine that need to be lubricated include bearings, piston sliding surfaces in the combustion chamber, cam sliding surfaces, and power transmission parts such as gears and chains. Examples of parts of the engine that need to be cooled include the back surface of the piston and parts that generate heat due to sliding.

[0018] The intake ports 16 and the exhaust ports 18 are passages formed inside the cylinder head 8. The upstream end of the intake port 16 opens to one side of the cylinder head 8 in the orthogonal direction PD, and the downstream end opens to a combustion chamber 20 inside the cylinder 6. The upstream end of the exhaust port 18 opens to the combustion chamber 20 inside the cylinder 6, and the downstream end opens to the other side of the cylinder head 8 in the orthogonal direction PD. An intake port 16 is formed for each cylinder, and they are lined up in the width direction WD. Similarly, an exhaust port 18 is formed for each cylinder, and they are lined up in the width direction WD.

[0019] External air is supplied as intake air from the intake port 16 to the combustion chamber 20, and fuel is injected into the combustion chamber 20 from the injector 22 to form a mixture of fuel and air. The mixture in the combustion chamber 20 is ignited by the spark plug 24 and burns. Exhaust gas after combustion is discharged to the outside of the engine from the exhaust port 18.

[0020] The engine E of this embodiment is equipped with intake valves 17 that open and close intake ports 16, and exhaust valves 19 that open and close exhaust ports 18. The intake valves 17 and exhaust valves 19 are opened and closed by a valve mechanism 21. In this embodiment, two intake valves 17 and two exhaust valves 19 are provided for each cylinder.

[0021] The valve train 21 opens and closes the intake valve 17 and the exhaust valve 19 in conjunction with the rotation of the crankshaft 2. In this embodiment, the valve train 21 has an intake valve drive mechanism 21a and an exhaust valve drive mechanism 21b that are independent for the intake side and the exhaust side. The intake valve drive mechanism 21a has an intake-side camshaft 21a provided with a cam that opens and closes the intake valve 17. The exhaust valve drive mechanism 21b has an exhaust-side camshaft 21b provided with a cam that opens and closes the exhaust valve 19.

[0022] As shown in Fig. 2, the engine E has a reciprocating direction transmission member 23 that extends in the reciprocating direction and transmits the rotation of the crankshaft 2 to the valve train 21. In this embodiment, a cam chain is used as the reciprocating direction transmission member 23. The cam chain is stretched between the crankshaft and the camshaft to transmit the rotation of the crankshaft to the camshaft. However, the reciprocating direction transmission member 23 is not limited to a chain and may be a drive belt or a push rod.

[0023] The cam chain 23 is disposed in a transmission member storage space CT. In this embodiment, the transmission member storage space CT is a cam chain tunnel CT that stores the cam chain 23, which is a reciprocating direction transmission member. The cam chain tunnel CT is formed in the cylinder 6 and the cylinder head 8, and extends in the reciprocating direction VD. In this embodiment, the cam chain tunnel CT is provided at an end of the engine in the width direction WD.

[0024] Although not shown, engine accessories are arranged on the side where the cam chain is arranged. In this embodiment, the accessories include an oil pump, a water pump, and a generator. These accessories receive the power required to drive them from the portion of the crankshaft that protrudes to the other side in the width direction.

[0025] An output shaft 25 is provided on one side in the width direction WD of the engine E (the left side in FIG. 2). The output shaft 25 is a part that mechanically outputs rotational power. In this embodiment, a propulsion propeller shaft is coaxially connected to the output shaft 25. The propeller shaft is connected to the output shaft 25 and is thereby rotationally driven together with the output shaft. In addition, a reduction mechanism 26 is provided on one side in the width direction of the engine E. The rotational force of the crankshaft 2 is reduced to a predetermined reduction ratio by the reduction mechanism 26 and transmitted to the output shaft 25. The output shaft 25 outputs the reduced rotational power of the crankshaft 2 as mechanical power. A propulsion propeller, which is a rotating body PB, is directly or indirectly attached to the output shaft 25.

[0026] The output shaft 25 is disposed on one side in the width direction of the crankcase 4. The output shaft 25 extends parallel to the crankshaft 2 and is disposed at a position shifted radially relative to the crankshaft 2. The tip portion of the output shaft 25, which is one end in the width direction WD, protrudes from the crankcase 4 in one side in the width direction.

[0027] The base end of the output shaft 25, which is the other end in the width direction WD, is supported by a bearing provided in the crankcase 4. More specifically, the bearing supporting the end of the output shaft 25 is provided on the widthwise outer wall of the crankcase 4, which is adjacent to one side of the combustion chamber 20 in the width direction WD. The crankcase 4 supports the output shaft 25 on a side inward in the width direction relative to the end face on one side in the width direction. In other words, the base end of the output shaft 25 is located on a side inward in the width direction relative to the end face on one side in the width direction of the crankcase 4.

[0028] The output shaft 25 is disposed offset in the reciprocating direction VD with respect to the crankshaft 2 and is disposed at a position overlapping with the cylinder 6 when viewed from the width direction WD. More specifically, the output shaft 25 is disposed on or near the axis of the combustion chamber 20. The output shaft 25 is disposed at the width end of the crankcase 4 opposite the width end where the cam chain tunnel CT is formed. The output shaft 25 is also disposed at the width end opposite the auxiliary machinery that drives the engine.

[0029] The engine E of this embodiment is equipped with a gear cover 28, which is a type of cover member that covers the reduction mechanism 26. The gear cover 28 covers the reduction mechanism 26 from the outside in the axial direction (width direction W) and from the radial direction. The gear cover 28 is detachably attached to the crankcase 4 by fastening members 29 such as bolts.

[0030] The gear cover 28 is provided with a bearing that supports the output shaft 26. In this manner, in this embodiment, the output shaft 25 is supported at both ends by the crankcase 4 and the gear cover 28.

[0031] In the following description, the side of the width direction WD of the engine E on which the output shaft 25 is arranged is referred to as one side of the width direction WD, and the opposite side is referred to as the other side of the width direction WD.

[0032] 4 is a cross-sectional view taken along an imaginary plane passing through the two axes of the crankshaft 2 and the output shaft 25. As shown in FIG. 4, the reduction gear mechanism 26 has a small-diameter input gear 34i provided on the crankshaft 2 side and a large-diameter output gear 34o provided on the output shaft 25. The input gear 34i and the output gear 34o mesh with each other, so that the rotation of the crankshaft 2 is reduced in speed and transmitted to the output shaft 25. In other words, the crankshaft 2 constitutes the input shaft of the reduction gear mechanism 26, and the output shaft 25 constitutes the output shaft of the reduction gear mechanism 26. In this embodiment, the input gear 34i and the output gear 34o are configured as "helical gears," but the present invention is not limited to this.

[0033] In this embodiment, the crankshaft 2 and the input shaft on which the input gear 34i is provided are formed as separate structures. The crankshaft 2 and the input shaft are connected via a joint structure CS. The joint structure CS further employs a damper structure that suppresses rotational fluctuations of the crankshaft 2. While the crankshaft 2 and the input gear 34i may be directly connected, in this embodiment, the crankshaft 2 and the input gear 34i are connected via a disc-shaped damper structure CS that is coaxial with the crankshaft 2. This damper structure is located axially inward of the input gear 34i.

[0034] A tip end 2a of the crankshaft 2, which is axially outer than the input gear 34i, is supported by the gear cover 28 via a rolling bearing 35. In this embodiment, a ball bearing is used as the rolling bearing 35, but this is not limiting. Also, a bearing portion 2b of the crankshaft 2, which is axially inner than the input gear 34i, is supported by the crankcase 4. In other words, the bearing portion 2b of the crankshaft 2 forms a sliding bearing. In this way, both ends of the crankshaft 2, outside and inside the input gear 34i, are supported.

[0035] The output shaft 25 has an inner end in the axial direction located within the crankcase 4. A tip end 25a of the output shaft 25, which is axially outer than the output gear 34io, is supported by a gear cover 28 via a rolling bearing 36. A base end 25b of the output shaft 25, which is axially inner than the output gear 34o, is supported by the crankcase 4 via a rolling bearing 38. In this embodiment, tapered roller bearings are used as the rolling bearings 36, 38, but the present invention is not limited to this. In this way, the output shaft 25 is supported at both ends, outside and inside the output gear 34o.

[0036] The output shaft 25 has a hollow shape and an internal space formed therein. In this embodiment, the internal space of the output shaft 25 functions as a flow path that guides hydraulic fluid for driving a variable pitch mechanism provided on the propeller shaft. Therefore, by connecting the output shaft 25 to the propeller shaft, a structure is formed in which the internal space of the output shaft 25 communicates with the hydraulic fluid flow path of the propeller shaft. The pressure of the hydraulic fluid that is guided to the variable pitch mechanism is adjusted by a governor, which will be described later.

[0037] As shown in Figure 1 or 2, an oil pump 30 is disposed in an oil storage space formed in the oil pan 14. The oil pump 30 pumps oil OL in the oil pan 14 to lubricated parts inside the engine. In other words, the oil pump 30 is a circulation pump that pumps and circulates the oil OL, which is a circulating fluid, to parts to which it is supplied. In the following description, "upstream" and "downstream" refer to the "upstream" and "downstream" directions of the flow of the oil OL, respectively.

[0038] 2 is first supplied to the main gallery 32. Of the passages inside the engine through which the oil OL pressurized by the oil pump 30 flows, the main gallery 32 is the passage with the largest diameter into which the oil OL from the oil pump 30 first flows. The main gallery 32 is also the passage with the highest pressure among the passages inside the engine.

[0039] The main gallery 32 may be a flow path in the oil flow path before the oil OL supplied from the oil pump 30 branches off. The main gallery 32 may also be a passage into which the oil OL from the oil pump 30 first flows. The main gallery 32 may be, for example, a passage before the oil OL branches off into a flow path leading to the crankshaft 2 or the cylinder head 8.

[0040] In this embodiment, the main gallery 32 is a passage formed in the crankcase 4, and extends in the width direction of the engine E, i.e., in the axial direction of the crankshaft 2. In other words, in this embodiment, the main gallery 32 constitutes an axial passage for flowing the circulating fluid (oil OL) in the axial direction of the crankshaft 2. The main gallery 32 is formed inside the wall that separates the inside and outside of the crankcase 4.

[0041] 1, in this embodiment, the main gallery 32 is formed on one wall of the crankcase 4 in the orthogonal direction PD. In this embodiment, the main gallery 32 is provided on the exhaust side in the orthogonal direction PD. More specifically, the main gallery 32 is formed in the upper crankcase 4b.

[0042] The main gallery 32 may be provided with an opening to a branch passage that guides the oil OL to each cylinder. For example, the main oil gallery 32 may be provided with oil jets that inject the oil OL onto the back of the piston 3, spaced apart in the axial direction. Also, for example, the main gallery 32 may be provided with branch passages that guide the oil OL to a support portion that supports the crankshaft 2, spaced apart in the axial direction.

[0043] In this embodiment, the oil pump 30 is driven in conjunction with the rotation of the crankshaft 2. More specifically, the rotational force of the crankshaft 2 is transmitted to the oil pump 30 by a power transmission member 34 such as a drive chain.

[0044] When the engine E shown in Figure 2 starts, the oil pump 30 is driven in conjunction with the rotation of the crankshaft 2. The oil OL in the oil pan 14 is pressurized by the oil pump 30 and supplied to the main gallery 32. The oil OL supplied to the main gallery 32 lubricates the parts of the engine E that need to be lubricated. After lubricating the parts that need to be lubricated, the oil OL returns to the oil pan 14 by its own weight.

[0045] The engine E of the present disclosure is equipped with a governor 40. The governor 40 adjusts and supplies hydraulic fluid for driving the variable pitch mechanism of the propeller. The variable pitch mechanism changes its pitch angle according to the pressure of the hydraulic fluid. The governor 40 is supplied with engine oil, which is a circulating fluid. The governor 40 is equipped with a fluid pump that adjusts the supplied circulating fluid by transmitting the rotation of the crankshaft 2. The supplied circulating fluid is thereby increased in pressure and supplied to the variable pitch mechanism as hydraulic fluid for operating the variable pitch mechanism.

[0046] The governor 40 adjusts the pitch angle of the propeller to maintain the target engine speed input by the driver. Specifically, when the speed of the propeller shaft falls below the target speed, the governor 40 changes the pressure of the hydraulic fluid so that the pitch angle reduces the rotational load on the propeller.

[0047] Furthermore, when the rotational speed of the propeller shaft becomes higher than the target rotational speed, the governor 40 changes the pressure of the hydraulic fluid so that the pitch angle is such that the rotational load on the propeller is large. In this way, the pressure of the hydraulic fluid is adjusted to adjust the pitch angle (propeller rotational load) and maintain the propeller rotational speed (engine rotational speed) at a predetermined value.

[0048] The governor 40 is provided with a lever for setting the target rotation speed. For example, the governor 40 has an eccentric weight supported by a spring disposed within a case. When the rotation speed transmitted from the crankshaft 2 to the governor 40 exceeds the rotation speed set by the lever, the weight is swung outward by centrifugal force. The governor 40 changes the pressure of the hydraulic fluid in response to the movement of the weight to increase the rotational load. When the rotation speed of the propeller transmitted from the crankshaft 2 to the governor 40 falls below the rotation speed set by the lever, the weight moves in the opposite direction, thereby changing the pressure of the hydraulic fluid to increase the rotational load. The target rotation speed can be changed depending on the angular displacement position of the lever. The lever may be angularly displaced manually or by an electric motor controlled by an ECU.

[0049] In this way, the governor 40 is driven by the rotational force of the crankshaft 2, and supplies the hydraulic fluid with the pressure of the oil OL adjusted to the variable pitch mechanism. That is, in this embodiment, the governor 40 constitutes an adjusting device that adjusts the pressure of the hydraulic fluid to control the variable pitch mechanism 42, which is a fluid-driven actuator.

[0050] In this embodiment, the gear ratio of the power transmission members is set so that the rotational force transmitted from the crankshaft 2 to the governor 40 is the same as the rotational speed of the propeller shaft, in other words, the output shaft 25. However, the rotational force transmitted from the crankshaft 2 to the governor 40 does not have to be the same as the rotational speed of the propeller shaft, and can be set arbitrarily to be the permissible rotational speed on the governor side. In other words, the gear ratio can be set arbitrarily as long as the structure can transmit power sufficient to drive the governor.

[0051] The governor 40 is connected to a connection surface formed on the outer surface of the crankcase 4. The connection surface is formed on the exhaust-side outer surface of the crankcase 4. The connection surface is formed closer to the output shaft side of the crankcase 4. The connection surface is formed on the upper crankcase 4b of the crankcase 4. The connection surface is formed on the upper crankcase 4b at a position close to the mating surface with the lower crankcase 4a. The connection surface is located closer to the crankshaft axis than the combustion chamber 20. In other words, the connection surface is located below the piston 3, which is located at bottom dead center. The connection surface is located closer to the crankshaft and spaced apart from the output shaft 25 in the reciprocating direction VD. The connection surface is located closer to the crankshaft than the main gallery 32 described above and above the crank axis.

[0052] The connecting surface is formed on the crankcase 4 on the other side in the width direction than the mating surface with the cover provided on one side in the width direction WD of the crankcase 4. The center of the connecting surface in the width direction is shifted to one side in the width direction from the center of the exhaust port opening located furthest to one side in the width direction. In addition, the end face on one side in the width direction of the connecting surface is located to one side in the width direction from the exhaust port opening located furthest to one side in the width direction. In addition, the end face on one side in the width direction of the connecting surface is located to one side in the width direction from the cylinder forming portion of the crankcase 4 that forms the cylinder 6.

[0053] The connection surface 44 is formed on a flat surface. In this embodiment, the connection surface 44 extends parallel to an imaginary plane that extends in two directions, the axial direction and the reciprocating direction. In other words, the connection surface 44 extends along a plane perpendicular to the radial direction of the crankshaft 2. More specifically, the connection surface 44 extends along a plane perpendicular to the radial direction of the crankshaft 2 and along the reciprocating direction. The connection surface does not have to be arranged parallel to the reciprocating direction, and may be formed on a surface inclined with respect to the reciprocating direction. Furthermore, the connection surface may be formed on a wall of the crankcase 4 on one side in the orthogonal direction, i.e., the exhaust side wall in this embodiment, so long as a surface to which the governor 40 can be fixed is formed.

[0054] In this way, the governor 40 is connected to a connecting surface 44 formed on a wall surface facing the orthogonal direction PD on the outer surface of the crankcase 4, i.e., on a wall surface on one side of the crankcase 4 in the orthogonal direction PD. In this embodiment, the connecting surface 44 is formed on the wall surface of the crankcase 4 on the side where the main gallery 32 is formed. Also, in this embodiment, the connecting surface 44 is formed on the wall surface of the crankcase 4 on the exhaust side. The governor 40 is attached to the crankcase 4 with fastening members 45 such as bolts.

[0055] In this embodiment, the governor 40 has a cylindrical outer shape. The governor 40 is connected to the crankshaft 2 with its axis perpendicular to the connection surface 44. In this embodiment, the governor 40 protrudes from the crankcase 4 in the orthogonal direction PD. The governor 40 includes a rotor housed within the case that rotates when power is applied from the crankshaft 2. In the following description, the rotational axis of the rotor within the governor may be referred to as the rotational axis of the governor.

[0056] A lever for setting the rotation speed is provided at the protruding end of the governor 40. By locating the lever at a position away from the cylinder 6, interference between the lever and the engine E is prevented, making it easier to angularly displace the lever.

[0057] The governor 40 of this embodiment is disposed on one side of the crankcase 4 in the engine width direction WD, i.e., in the axial direction AX1 of the crankshaft 2. In other words, the governor 40 is disposed closer to the output shaft 25 in the crankcase 4. More specifically, the governor 40 is disposed closer to the inner end of the output shaft 25 in the axial direction.

[0058] 3, the rotational axis AX2 of the governor 40, i.e., the rotational axis AX2 of the fluid-driven actuator 42, is perpendicular to the connection surface 44. In other words, in this embodiment, the rotational axis AX2 of the governor 40 is perpendicular to an imaginary plane that includes the axis AX1 of the crankshaft 2 and the reciprocating axis of the piston.

[0059] 5 is a cross-sectional view taken along an imaginary plane passing through the two axes of the governor 40 and the bevel gear shaft 48. As shown in FIG. 5, a governor rotating shaft 50 provided inside the case of the governor 40 receives rotational force from a bevel gear shaft extending parallel to the crankshaft 2. The rotation of the crankshaft 2 is transmitted to the governor 40 via a bevel gear (bevel gear) 46. More specifically, the bevel gear 46 has a primary gear 46i provided on the bevel gear shaft 48 and a secondary gear 46o provided on the rotating shaft 50 of the governor 40. When the primary gear 46i and the secondary gear 46o mesh with each other, the direction of rotation of the bevel gear shaft 48 is changed and the rotation is transmitted to the rotating shaft 50 of the governor 40.

[0060] As described above, the bevel gear shaft 48 is disposed parallel to the crankshaft 2. One end 48a of the bevel gear shaft 48 on the axially outer side is supported by the gear cover 28 via the rolling bearing 52, and the other end 48b on the axially inner side is supported by the crankcase 4 via the rolling bearing 54. In this embodiment, the rolling bearing 52 on the axially outer side is a ball bearing, and the rolling bearing 54 on the axially inner side is a needle bearing, but the present invention is not limited to this.

[0061] 2, the bevel gear shaft 48 is disposed between the output shaft 25 and the crankshaft 2 in the reciprocating direction. The bevel gear shaft 48 is also disposed radially outward of the output gear 34o. The bevel gear shaft 48 is also disposed radially outward of the damper structure described above.

[0062] In this embodiment, the rotational force is transmitted to the bevel gear shaft 48 from the output shaft 25 via a drive chain 55, which is an endless belt-like power transmission member. In other words, the governor 40 is driven by the rotational power of the output shaft 25. In this embodiment, a drive chain is used as the power transmission member 55, but the power transmission member 55 is not limited to a drive chain and may be a timing belt, gears, or the like.

[0063] As shown in Fig. 4, a first sprocket 56 is provided on the output shaft 25 at a position axially more inward than the output gear 34o. Also, as shown in Fig. 5, a second sprocket 58 is provided on the bevel gear shaft 48 at a position axially more outward than the primary gear 46i. A drive chain 55 is stretched across the first sprocket 56 and the second sprocket 58 shown in Fig. 3.

[0064] By positioning sprocket 56 axially inward of output gear 34o, interference between drive chain 55 and output gear 34o can be prevented. Sprocket 58 is positioned so as to overlap with damper structure CS in the width direction WD, and is positioned offset from damper structure CS in a cross section perpendicular to the axial direction. This prevents interference between sprocket 58 and damper structure CS, allowing sprocket 58 to be positioned axially inward.

[0065] The governor 40 has a case body 60 that houses adjustment parts such as a weight, spring, and pressure adjustment valve that rotate together with the governor rotating shaft. The case body 60 is detachably attached to the connecting surface 44 of the crankcase 4 with fastening members 65 such as bolts, with the tip portion 50a of the governor rotating shaft 50 and the secondary gear 46o protruding from the case body 60. In this embodiment, the governor rotating shaft 50 is supported by the case body 60 via a bearing 62. The bearing 62 is, for example, a rolling bearing such as a ball bearing, but is not limited to this.

[0066] 6 is a cross-sectional view taken along an imaginary plane that is perpendicular to the output shaft 25 and passes through the governor axis. As shown in FIG. 6, in this embodiment, oil OL1 is supplied to the governor 40 from the main gallery 32 through an inlet opening 64 formed in the connection surface 44. Oil OL may be supplied to the governor 40 from an oil passage other than the main gallery 32.

[0067] More specifically, a governor introduction passage is formed that connects the main gallery 32 and the inlet opening 64. Oil is guided from the main gallery 32 through the governor introduction passage to the inlet opening 64. The governor introduction passage is formed inside the wall surface of the crankcase 4.

[0068] The pressure of the oil OL supplied to the governor 40 is adjusted according to the rotation speed of the governor rotating shaft. The oil OL whose pressure has been adjusted is supplied as a hydraulic fluid to a hydraulic fluid passage 68 via an outlet opening 66 formed in the connection surface 44. The hydraulic fluid passage 68 extends inside the crankcase 4 toward the output shaft 25.

[0069] Specifically, the hydraulic fluid passage 68 is formed inside one widthwise side wall surface that separates the inside and outside of the crankcase 4. In other words, the hydraulic fluid passage 68 is formed in a portion of the crankcase 4 that supports the output shaft 25.

[0070] 4, the output shaft 25 is a hollow shaft body, and has an in-shaft passage 69 formed therein. An introduction opening 69a for introducing oil OL into the in-shaft passage 69 inside the output shaft 25 is formed at the base end 25b on the axially inner side of the output shaft 25.

[0071] In the crankcase 4, an oil space filled with oil is formed between the base end of the output shaft 25 and a wall surface. In other words, a gap is formed between the base end of the output shaft 25 and the crankcase 4 in the width direction WD. The above-mentioned working fluid passage 68 communicates with the oil space. As a result, working fluid whose pressure is adjusted by the governor 40 according to the rotation speed of the crankshaft 2 is supplied to an in-shaft passage 69 inside the output shaft 25 via the working fluid passage 68 and the oil space.

[0072] An outlet opening 69b is formed in the axially inner tip end 25a of the output shaft 25 to outlet the oil OL supplied into the in-shaft passage 69. The working fluid is supplied from this outlet opening 69b to a variable pitch mechanism provided on a propeller shaft connected to the output shaft 25. In other words, the oil OL whose pressure is adjusted by the governor 40, which is an adjustment device, is supplied to the variable pitch mechanism, which is a fluid-driven actuator attached to the tip end of the output shaft 25.

[0073] According to the above configuration, the governor 40 is attached to a connection surface 44 formed on the wall surface of the crankcase 4. This allows the cover structure to be made more compact than when the governor 40 is connected to the cover 28, and the drive device including the cover 28 and the engine E can be made more compact.

[0074] The governor 40 is connected to a connection surface 44 of the crankcase 4 that faces the orthogonal direction PD. In other words, the connection surface 44 extends along a plane that is perpendicular to the radial direction of the crankshaft 2. More specifically, the connection surface 44 extends along a plane that is perpendicular to the radial direction of the crankshaft 2 and that is along the reciprocating direction. In this way, by facing the orthogonal direction PD, the connection surface 44 can be easily formed to be wider than when the connection surface 44 is formed on an axial end surface of the crankcase 4. This makes it easier to ensure a space for arranging the adjustment device, improving the flexibility of the adjustment device's mounting position.

[0075] Specifically, the governor 40 is connected to a connection surface 44 on the side of the crankcase 4 where the main gallery 32 is formed. This shortens the governor introduction passage 80 between the governor 40 and the main gallery 32. Furthermore, because relatively high-pressure oil OL is supplied from the main gallery 32 to the governor 40, the amount of pressure increase required for the governor 40 can be reduced, and the pressure regulating operation of the governor 40 can be stabilized.

[0076] 5, in this embodiment, the rotational axis AX2 of the governor 40 is perpendicular to the connection surface 44, and the rotation of the crankshaft 2 is transmitted to the governor 40 via the bevel gear 46. Compared to connecting the governor 40 to the crankcase 4 so that the rotational axis AX2 is parallel to the crankshaft 2, the number of bends in the governor introduction passage 80 and the hydraulic fluid passage 68 can be reduced, simplifying the passage structure. Furthermore, because the rotating shaft 50 of the governor 40, on which the bevel gear 46 is mounted, is supported by the rolling bearing 62, sliding resistance can be reduced compared to when the rotating shaft 50 is directly supported.

[0077] In this embodiment, as shown in Fig. 4, the rotation of the crankshaft 2 is reduced in speed by the reduction mechanism 26 and transmitted to the output shaft 25, and the rotational force of this output shaft 25 drives the governor 40 shown in Fig. 5. As a result, reduced rotational force is obtained from the output shaft 25, eliminating the need for a separate reduction mechanism dedicated to the governor.

[0078] As shown in FIG. 2, the rotation of the output shaft 25 is transmitted to the governor 40 via a drive chain 55. If the output shaft 25 is connected to a gear to obtain rotational force from the output shaft 25, a large gear with the same diameter as the output gear 34o shown in FIG. 4 would be required. By using the drive chain 55 as in this embodiment, there is no need to prepare a large gear, making it possible to achieve a more compact design than with gear connection. The sprockets, chain guides, etc. of the drive chain 55 can be positioned more inward in the width direction (WD) than the output gear 34o, allowing for effective use of internal space and a compact layout.

[0079] Furthermore, by arranging the drive chain 55 in a position overlapping with the damper structure CS, the internal space can be effectively utilized, resulting in a compact layout. Both ends of the output shaft 25 around which the drive chain 55 is stretched are supported by the cover member 28 and the crankcase 4, respectively. By supporting both ends in this manner, sufficient support strength for the output shaft 25 is ensured.

[0080] Moreover, the governor 40 is attached to a portion of the crankcase 4 close to the output shaft 25. With this configuration, by arranging the governor 40 close to an opening formed in the output shaft 25, the hydraulic fluid passage 68 extending from the governor 40 to the output shaft 25 can be shortened.

[0081] The governor 40 is disposed near the base end 25b of the output shaft 25, more specifically, near the opening of the output shaft 25. This configuration allows the hydraulic fluid passage 68 extending from the governor 40 to the opening 69a at the base end 25b of the output shaft 25 to be shortened.

[0082] 2, the governor 40 is disposed on one side of the crankcase 4 in the axial direction of the crankshaft 2, i.e., in the engine width direction WD, and the cam chain tunnel CT is formed on the other side of the crankcase in the engine width direction WD. With this configuration, if the governor 40 is disposed on the cam chain tunnel CT side, the governor introduction passage 80 and the hydraulic fluid passage 68 must be formed to avoid the space through which the cam chain 23 passes, which complicates the formation of the passages. In contrast, in the above embodiment, it is easy to form the governor introduction passage 80 and the hydraulic fluid passage 68 without interfering with the cam chain tunnel CT.

[0083] 3, the governor 40 is attached to a mounting surface 70 on the side of the crankcase 4 where the main gallery 32 is formed. Here, the mounting surface 70 refers to a portion of the wall of the crankcase 4 that is adjacent to or close to the main gallery 32. In this embodiment, the mounting surface 70 includes not only a surface of the crankcase 4 that faces the orthogonal direction PD, but also a surface that faces the width direction WD.

[0084] According to this configuration, the oil OL can be guided to the governor 40 from the main gallery 32 adjacent to or close to the governor 40, and the passage connecting the main gallery 32 and the governor 40 can be shortened.

[0085] The governor 40 is also positioned at one end in the width direction WD. This allows it to be located away from the exhaust pipe, exhaust ports, etc., thereby reducing the impact of exhaust heat on the governor 40. The governor 40 is also positioned closer to the crankshaft than the main gallery 32, and is positioned near the mating surface between the upper crankcase 4b and the lower crankcase 4a. This allows it to be located away from the exhaust pipe, exhaust ports, etc., thereby reducing the impact of exhaust heat on the governor 40. Because the governor 40 is positioned away from the exhaust port in this way, it is easy to prevent interference with the exhaust port, improving the degree of freedom in designing the exhaust port.

[0086] The governor 40 is formed in a region of the crankshaft 2 that protrudes in the orthogonal direction PD and serves as a space for accommodating the connecting rod. This allows the governor 40 to be connected to a relatively flat surface, making it easy to form a flat surface for connecting the governor 40. Also, by covering the connection surface 44 where the governor 40 is attached, the engine's versatility can be enhanced by allowing it to be used in an engine in which the governor 40 cannot be attached.

[0087] Furthermore, by connecting the governor 40 to the connection surface 44, the inlet opening on the crankcase side and the inlet opening on the governor side can be made to face each other. This eliminates the need for special connection work to connect the oil passages to each other, improving workability. Similarly, by connecting the governor 40 to the connection surface 44, the outlet opening on the crankcase side and the inlet opening on the governor side can be made to face each other. This eliminates the need for special passage connection work to connect the oil passages to each other, improving workability.

[0088] The drive unit including the engine of the present disclosure may include a fluid-driven actuator that is driven by fluid energy generated by the rotational force of the crankshaft 2. The fluid-driven actuator may be a variable pitch mechanism for a propeller that operates by the drive described above. Therefore, the drive unit of the present disclosure is preferably mounted on an airplane, a ship, or the like that is equipped with a variable pitch mechanism. The fluid-driven actuator may also be an actuator other than a variable pitch mechanism, and may be applied to, for example, agricultural machinery or construction machinery that is equipped with a fluid-driven mechanism such as a piston, or a mobile object such as a lawnmower that is equipped with an HST (Hydrostatic Transmission). The drive unit of the present disclosure can be made compact, and is therefore preferably mounted on a mobile object.

[0089] The drive unit of the present disclosure may also be mounted on a ground-type system that includes a fluid-driven actuator other than the moving body described above. In the present embodiment, the pressure of the hydraulic fluid is adjusted by the adjusting device, but the fluid-driven actuator may also be controlled by adjusting fluid energy other than pressure, such as the flow rate or flow velocity.

[0090] The oil pump 30 may be realized by a scavenge pump and a feed pump. Some or all of the oil pumped by the oil pump 30 may pass through an oil cooler before being supplied to the main gallery 32. The main gallery 32 may be formed in the wall of the crankcase 4 on the intake side.

[0091] The output shaft 25 may be disposed at a position offset from the cylinder axis in the orthogonal direction PD. The structure of the reduction mechanism 36 in the above embodiment is an example, and the structure can be modified as appropriate to obtain a desired speed ratio. The present disclosure also includes cases where one or more of the accessories are disposed on the output shaft side.

[0092] A circulating fluid other than engine oil may be used as the circulating fluid supplied to the governor 40. For example, a liquid dedicated to the variable pitch mechanism other than engine oil may be supplied to the governor 40. The working fluid adjusted by the governor 40 may be supplied to the fluid-driven actuator through a passage outside the crankcase 4. In the above embodiment, an example has been described in which the crankshaft 2 and the input gear 34i are connected by the joint structure CS, but the input gear 34i may also be directly connected to the crankshaft 2.

[0093] The arrangement and structure of the governor 40 are not limited to those in the above embodiment. For example, the governor 40 may be connected to the crankcase 4. The rotational axis AX2 of the governor 40 may be arranged in a direction intersecting the rotational axis AX1 of the crankshaft 2, or may be arranged in a direction that forms a twisted position with respect to the rotational axis AX1 of the crankshaft 2. The rotational axis AX2 of the governor 40 may be parallel to the rotational axis AX1 of the crankshaft 2. The governor 40 may be connected to the wall surface of the crankcase 4 on the intake side.

[0094] The engine of the present disclosure includes the following aspects 1 to 13. [Aspect 1] a crankcase that supports the rotation of the crankshaft; a circulation pump for circulating and pumping the circulating fluid to a supply portion within the crankcase; an adjusting device that is driven by a rotational force of the crankshaft, adjusts the pressure of the circulating fluid pressure-fed by the circulating pump to generate a working fluid, and controls a fluid-driven actuator by the working fluid, An engine in which the adjustment device is connected to a connection surface formed on a wall surface of the crankcase on one side in a direction perpendicular to both the axial direction of the crankshaft and the reciprocating direction of the piston. [Aspect 2] In the engine according to aspect 1, an axial passage through which the circulating fluid flows in an axial direction of the crankshaft is formed in the crankcase, The adjusting device is supplied with circulating fluid from the axial passage through an opening formed in the wall surface. [Aspect 3] In the engine according to aspect 1 or 2, the connection surface is formed on a wall surface facing the orthogonal direction on the side where a main gallery is formed. [Aspect 4] The engine according to any one of aspects 1 to 3, further comprising an output shaft that outputs rotational power of the crankshaft, The adjusting device is mounted in the crankcase near the output shaft, and pressure-feeds the hydraulic fluid to a passage formed in the output shaft to guide the hydraulic fluid. [Aspect 5] In the engine according to aspect 4, one axial end of the output shaft is located within the crankcase, an opening for introducing the hydraulic fluid into the output shaft is formed at one axial end of the output shaft; The adjustment device is disposed near one axial end of the output shaft of the engine. [Aspect 6] In the engine according to any one of aspects 1 to 5, the crankcase is formed with a transmission member housing space for housing a reciprocating direction transmission member that transmits power of the crankshaft in the reciprocating direction toward a valve that opens and closes a combustion chamber, The adjustment device is disposed at a position separated from the transmission member accommodating space of the engine. [Aspect 7] The engine according to any one of aspects 1 to 6, further comprising: an output shaft that outputs rotational power of the crankshaft; a power transmission member that transmits rotational power from the output shaft to the adjustment device, The engine, wherein the adjustment device is disposed in the crankcase closer to the output shaft. [Aspect 8] The engine according to any one of aspects 1 to 7, further comprising a speed reduction mechanism that reduces the rotation speed of the crankshaft, The adjustment device is an engine that is driven by the rotational force of the output shaft transmitted directly or indirectly. [Aspect 9] The engine according to any one of aspects 1 to 8, wherein rotation of the crankshaft is transmitted to the adjusting device via an endless belt-shaped power transmission member. [Aspect 10] In the engine according to any one of the first to ninth aspects, rotation of the crankshaft is transmitted to the adjusting device via a power transmission member; a cover member that covers at least a portion of the crankcase, an engine in which both ends of a shaft supporting the power transmission member are supported by the cover member and the crankcase, respectively; [Aspect 11] In the engine according to any one of aspects 1 to 10, a rotation axis of the pressure boost regulator device is perpendicular to the wall surface, An engine in which the rotation of the crankshaft is transmitted to the pressure boost regulator via a bevel gear. [Aspect 12] a crankcase that supports the rotation of the crankshaft; a circulation pump for circulating and pumping the circulating fluid to a supply portion within the crankcase; an adjusting device that is driven by a rotational force of the crankshaft, adjusts the circulating fluid pressure-fed by the circulating pump to generate a working fluid, and controls a fluid-driven actuator by the working fluid, The adjustment device is attached to a mounting surface portion of the crankcase on the side where a main gallery is formed, An engine in which circulating fluid from the main gallery is supplied to the regulator. [Aspect 13] a crankcase that supports the rotation of the crankshaft; a governor driven by the rotational force of the crankshaft, The governor is connected to a connection surface formed on an outer wall surface of the crankcase of the engine.

[0095] The present disclosure is not limited to the above embodiments, and various additions, modifications, or deletions are possible without departing from the spirit and scope of the present disclosure. For example, the number of cylinders of the engine is not limited to six, and may be less than six or seven or more. The engine may be provided with a supercharger such as a turbocharger or a supercharger.

[0096] Furthermore, the engine of the above embodiment may be configured to be able to be driven by mounting an adjusting device that adjusts the fluid energy of the hydraulic fluid. In other words, the crankcase may be formed with a connection surface to which the adjusting device is mounted and a passage for supplying lubricating fluid to the adjusting device. A configuration in which an adjusting device and a power transmission device that transmits power from the crankshaft to the adjusting device are retrofitted is also within the scope of the present disclosure.

[0097] Furthermore, the drive unit of the present disclosure preferably includes two energy extraction structures: an output shaft that mechanically extracts power from the crankshaft; and an adjustment device that adjusts fluid energy converted from the power of the crankshaft. The mounting device on which the drive unit is mounted can be selected as appropriate. In the present embodiment, a propeller is attached to the output shaft, but this is not limited to this. In other words, a rotating body other than a propeller may be directly or indirectly attached to the output shaft. For example, the rotating body directly or indirectly attached to the output shaft may be a driving wheel of a vehicle, a turbine rotor blade, a compressor impeller, a blower fan, or the like. Furthermore, a passage for guiding a working fluid may be formed separately from the internal space of the output shaft.

[0098] Furthermore, the engine may employ a valve train structure that opens and closes the valves, such as an OHC structure in which a cam is provided above the cylinder, or an OHV structure in which the cam is provided below the cylinder. Furthermore, a transmission member accommodating space such as a cam chain tunnel may be located on one side of the width direction, or on the other side of the width direction or in the center of the width direction. In this way, existing engine structures can be applied to the engine itself. Furthermore, the mounting orientation of the engine on the mounting device described above is not limited, and the engine may be mounted in other orientations. [Explanation of symbols]

[0099] 2 crankshaft 4 crankcase 23 Cam chain (reciprocating direction transmission member) 25 output shaft 26 Reduction mechanism 28 Gear cover (cover member) 30 Oil pump (circulation pump) 32 Main Gallery 40 Governor (regulating device) 42 Variable pitch mechanism (fluid-driven actuator) 44 Connection Surface 46 Bevel gear 48 Bevel gear shaft 50 Governor rotating shaft 55 Drive chain (power transmission member) 64 Entrance opening 68 Hydraulic fluid passage 69 In-shaft passage 69a Introduction opening 70 Mounting surface CT cam chain tunnel (storage space for transmission components) E-Engine PD Orthogonal Direction VD Reciprocating direction (piston reciprocating direction) WD width direction (axial direction of crankshaft)

Claims

1. a crankcase that supports the rotation of the crankshaft; a circulation pump for circulating and pumping the circulating fluid to a supply portion within the crankcase; an adjusting device that is driven by a rotational force of the crankshaft, adjusts the pressure of the circulating fluid pressure-fed by the circulating pump to generate a working fluid, and controls a fluid-driven actuator by the working fluid, An engine in which the adjustment device is connected to a connection surface formed on a wall surface of the crankcase on one side in a direction perpendicular to both the axial direction of the crankshaft and the reciprocating direction of the piston.

2. 2. The engine according to claim 1, wherein the crankcase is formed with an axial passage through which the circulating fluid flows in the axial direction of the crankshaft, The adjusting device is supplied with circulating fluid from the axial passage through an opening formed in the wall surface.

3. 3. The engine according to claim 1, wherein the connecting surface is formed on a wall surface facing the orthogonal direction on the side where a main gallery is formed.

4. 3. The engine according to claim 1, further comprising an output shaft that outputs the rotational power of the crankshaft, The adjusting device is mounted in the crankcase near the output shaft, and pressure-feeds the hydraulic fluid to a passage formed in the output shaft.

5. 5. The engine according to claim 4, wherein one axial end of the output shaft is located within the crankcase, an opening for introducing the hydraulic fluid into the output shaft is formed at one axial end of the output shaft; The adjustment device is disposed near one axial end of the output shaft of the engine.

6. 3. The engine according to claim 1, wherein the crankcase is formed with a transmission member accommodating space for accommodating a reciprocating direction transmission member that transmits the power of the crankshaft in the reciprocating direction toward a valve that opens and closes a combustion chamber, The adjustment device is disposed at a position separated from the transmission member accommodating space of the engine.

7. 3. The engine according to claim 1, further comprising: an output shaft that outputs the rotational power of the crankshaft; a power transmission member that transmits rotational power from the output shaft to the adjustment device, The engine, wherein the adjustment device is disposed in the crankcase closer to the output shaft.

8. 3. The engine according to claim 1, further comprising a speed reduction mechanism for reducing the rotation speed of the crankshaft, The adjustment device is an engine that is driven by the rotational force of the output shaft transmitted directly or indirectly.

9. 3. The engine according to claim 1, wherein the rotation of the crankshaft is transmitted to the adjusting device via an endless belt-like power transmission member.

10. 3. The engine according to claim 1, wherein the rotation of the crankshaft is transmitted to the adjusting device via a power transmission member, a cover member that covers at least a portion of the crankcase, an engine in which both ends of a shaft supporting the power transmission member are supported by the cover member and the crankcase, respectively;

11. 3. The engine according to claim 1, wherein the rotation axis of the pressure boost regulator is perpendicular to the wall surface, An engine in which the rotation of the crankshaft is transmitted to the pressure boost regulator via a bevel gear.

12. a crankcase that supports the rotation of the crankshaft; a circulation pump for circulating and pumping the circulating fluid to a supply portion within the crankcase; an adjusting device that is driven by a rotational force of the crankshaft, adjusts the circulating fluid pressure-fed by the circulating pump to generate a working fluid, and controls a fluid-driven actuator by the working fluid, The adjustment device is attached to a mounting surface portion of the crankcase on the side where a main gallery is formed, An engine in which circulating fluid from the main gallery is supplied to the regulator.

13. a crankcase that supports the rotation of the crankshaft; a governor driven by the rotational force of the crankshaft, The governor is connected to a connection surface formed on an outer wall surface of the crankcase of the engine.

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