engine

Abstract

To provide technique capable of improving durability and reliability of an engine.SOLUTION: An engine according to an embodiment includes a crankshaft, a first gear attached to one end side of the crankshaft, a second gear attached to the other end side of the crankshaft, and a plurality of driven gears meshed with one of the first gear and the second gear. The first gear is meshed with a first driven gear having the largest driving torque at the maximum output of the engine among the plurality of driven gears. The second gear is meshed with a second driven gear having the second largest driving torque at the maximum output of the engine among the plurality of driven gears.SELECTED DRAWING: Figure 8

Description

Technical Field

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[0001] The present invention relates to an engine.

Background Art

[0002] Conventionally, an engine that drives a plurality of auxiliary machines such as a fuel injection pump, a cooling water pump, and a lubricating oil pump using the power of a crankshaft is known (see, for example, Patent Document 1). Patent Document 1 discloses a configuration in which power is transmitted to a fuel injection pump, a cooling water pump, and a lubricating oil pump by a crank gear attached to one end of a crankshaft.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In the case of a configuration in which a single crank gear attached to a crankshaft drives a plurality of auxiliary machines, a large load is likely to be applied to the crank gear. If it is possible to suppress the load applied to the crank gear from becoming too large, the durability of the crank gear can be improved. As a result, it is expected that the durability and reliability of the engine will be improved.

[0005] An object of the present invention is to provide a technique capable of improving the durability and reliability of an engine.

Means for Solving the Problems

[0006] An exemplary engine of the present invention comprises a crankshaft, a first gear mounted on one end of the crankshaft, a second gear mounted on the other end of the crankshaft, and a plurality of driven gears that mesh with either the first gear or the second gear. The first gear meshes with the first driven gear among the plurality of driven gears that has the greatest driving torque at the engine's maximum output. The second gear meshes with the second driven gear among the plurality of driven gears that has the second greatest driving torque at the engine's maximum output. [Effects of the Invention]

[0007] According to the exemplary present invention, the durability and reliability of the engine can be improved. [Brief explanation of the drawing]

[0008] [Figure 1] Left side view showing the general configuration of the engine. [Figure 2] Front view showing the general configuration of the engine. [Figure 3] Plan view showing the general configuration of the engine. [Figure 4] A schematic diagram illustrating the injectors found in an engine. [Figure 5] A schematic diagram illustrating the cooling system of the engine. [Figure 6] A schematic diagram illustrating the lubrication system of an engine. [Figure 7] A schematic perspective view showing the crankshaft and auxiliary components driven by the rotation of the crankshaft, which are part of the engine. [Figure 8] A perspective view showing the approximate configuration of the crankshaft of the engine. [Figure 9] A diagram showing the approximate configuration of the gear arrangement at the rear of the engine. [Figure 10] A diagram showing the approximate configuration of the gear arrangement at the front of the engine. [Figure 11] Diagram illustrating the engine related to the first modified example. [Figure 12] Diagram illustrating the engine related to the second modified example. [Modes for carrying out the invention]

[0009] Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the XYZ coordinate system will be shown as a three-dimensional Cartesian coordinate system where appropriate. In the following description, the X direction will be the front-rear direction, the Y direction the left-right direction, and the Z direction the up-down direction. The +X side will be the front side, and the -X side the rear side. The +Y side will be the left side, and the -Y side the right side. The +Z side will be the upper side, and the -Z side the lower side. In detail, the direction in which the center line J of the crankshaft (output shaft) shown in Figure 1 extends will be defined as the front direction. The side on which the cylinder block 11 is positioned relative to the flywheel (not shown) housed in the flywheel housing 3 will be the front side. The side on which the oil pan 2 is positioned relative to the cylinder block 11 will be defined as the lower side, and the up-down direction will be defined as the down side. The direction perpendicular to the front-rear direction and the up-down direction will be defined as the left-right direction, and the side that is to the left when viewed from front to rear will be the left side, and the side that is to the right will be the right side. These directions are merely names used for explanatory purposes and are not intended to limit the actual positional relationships and directions.

[0010] <1. Engine Overview> Figure 1 is a left side view showing a schematic configuration of engine 100 according to an embodiment of the present invention. Figure 2 is a front view showing a schematic configuration of engine 100 according to an embodiment of the present invention. Figure 3 is a top view showing a schematic configuration of engine 100 according to an embodiment of the present invention. The outline of engine 100 will be explained mainly with reference to Figures 1 to 3.

[0011] Engine 100 is, for example, an engine used for power generation. However, engine 100 is not limited to power generation engines; it may also be an engine used for other purposes, such as a ship propulsion engine. Engine 100 is a diesel engine. Engine 100 mainly comprises an engine body 1 and an oil pan 2. The engine body 1 comprises a cylinder block 11, a head block 12, and a head cover 13.

[0012] Inside the cylinder block 11, a plurality of pistons (not shown) and a crankshaft 10 (refer to FIGS. 7 and 8 described later) connected to each piston and extending in the front-rear direction are arranged. That is, the engine 100 includes the crankshaft 10. The crankshaft 10 converts the reciprocating motion of the piston into a rotational motion. A flywheel (not shown) housed in the flywheel housing 3 is attached to the rear end of the crankshaft 10. The flywheel rotates integrally with the crankshaft 10 and is used to extract the power of the engine 100.

[0013] The cylinder block 11 has a plurality of cylinders 14 (refer to FIG. 4 described later) arranged in the front-rear direction on each of the left and right sides. Each of the plurality of pistons is arranged within each cylinder 14. Note that the engine 100 is, as an example, a V-type 12-cylinder engine, and the number of cylinders 14 arranged in the front-rear direction on each of the left and right sides is six.

[0014] The head block 12 is arranged to overlap above each cylinder 14. That is, the engine body 1 has six head blocks 12 arranged in the front-rear direction on each of the left and right sides. Each head block 12 has an intake port (not shown) for supplying gas to the combustion chamber composed of the cylinder 14, the head block 12, and the piston, and an exhaust port (not shown) for exhausting gas from the combustion chamber.

[0015] The head cover 13 is arranged above each head block 12. That is, the engine body 1 has six head covers 13 arranged in the front-rear direction on each of the left and right sides. Each head cover 13 covers the intake valve and the exhaust valve (not shown) arranged in the head block 12. An injector 16 (refer to FIG. 4 described later) is attached to each head cover 13.

[0016] FIG. 4 is a schematic diagram for explaining an injector 16 included in the engine 100 according to an embodiment of the present invention. In FIG. 4, a cylinder block 11 having a cylinder 14 is also shown to facilitate understanding of the injector 16. Hereinafter, among the columns of cylinders 14 (cylinder columns 15) included in the engine 100, the cylinder column arranged in the front-rear direction on the left side of the engine 100 is referred to as the left cylinder column 15L, and the cylinder column arranged in the front-rear direction on the right side is referred to as the right cylinder column 15R. One injector 16 is provided for each cylinder 14 constituting the left cylinder column 15L. Also, one injector 16 is provided for each cylinder 14 constituting the right cylinder column 15R. Hereinafter, the injector 16 provided corresponding to the left cylinder column 15L is referred to as the left injector 16L, and the injector 16 provided corresponding to the right cylinder column 15R is referred to as the right injector 16R. In the present embodiment, the number of the left injector 16L and the right injector 16R is six each.

[0017] One end portion (lower end portion) of each injector 16 where an injection port for injecting fuel is provided faces the combustion chamber. Each injector 16 injects fuel supplied from a fuel pump 4 that discharges fuel at a high pressure into the combustion chamber via a high-pressure fuel pipe 17 at an appropriate timing. The piston reciprocates by the force generated by the combustion of the fuel injected into the combustion chamber. In the present embodiment, the fuel pump 4 is arranged behind the left side surface of the engine 100.

[0018] The cylinder column 15, the head block 12, and the head cover 13 provided on the left side of the engine 1构00 constitute a left bank LB. The cylinder column 15, the head block 12, and the head cover 13 provided on the right side of the engine 100 constitute a right bank RB.

[0019] Also, the engine 100 includes an intake manifold 5 and an exhaust manifold 6.

[0020] The intake manifold 5 distributes the intake air, which is air or a fuel-air mixture supplied from the supercharger 7 (details of which will be described later), to each cylinder (combustion chamber). More specifically, the intake manifold 5 is located on each of the left and right sides of the engine body 1, corresponding to the cylinder rows 15L and 15R, respectively. Both intake manifolds 5 on the left and right sides extend in the front-to-back direction. Hereinafter, the intake manifold 5 located on the left side corresponding to the left cylinder row 15L will be referred to as the left intake manifold 5L. The intake manifold 5 located on the right side corresponding to the right cylinder row 15R will be referred to as the right intake manifold 5R.

[0021] The exhaust manifold 6 collects the exhaust gas from each cylinder 14 (combustion chamber). More specifically, there are two exhaust manifolds 6, one for each of the cylinder rows 15L and 15R located on the left and right sides, respectively. Both exhaust manifolds 6 extend in the front-to-back direction. The two exhaust manifolds 6 are positioned side by side inside the V-bank, which is formed by the left and right banks LB and RB that make up the V-type engine. Hereinafter, the exhaust manifold 6 located on the left side of the V-bank, corresponding to the left cylinder row 15L, will be referred to as the left exhaust manifold 6L. The exhaust manifold 6 located on the right side of the V-bank, corresponding to the right cylinder row 15R, will be referred to as the right exhaust manifold 6R.

[0022] The supercharger 7 is located at the rear upper part of the engine 100. The supercharger 7 pressurizes and compresses air or air-fuel mixture supplied from outside the engine 100 and supplies it to the intake manifold 5 via the intercooler 8. The supercharger 7 is a turbocharger that is driven by exhaust gas supplied from the exhaust manifold 6.

[0023] The intercooler 8, which is connected to the intake manifold 5, is supplied with coolant by the drive of the first coolant pump 18, and cools the intake air. In this embodiment, the coolant is coolant water. However, the coolant may be a liquid other than water, such as antifreeze. Antifreeze is, for example, a liquid obtained by mixing pure water and ethylene glycol in a predetermined ratio. Hereinafter, the first coolant pump 18 will be referred to as the low-temperature water pump 18. In this embodiment, the low-temperature water pump 18 is located on the front right side of the engine 100. The intake air supplied from the supercharger 7 is pressurized and compressed, generating compression heat and raising its temperature. The intercooler 8 cools the intake air by exchanging heat between the coolant water and the pressurized and compressed intake air. That is, by providing the intercooler 8, the temperature of the intake air supplied to the intake manifold 5 can be adjusted to a desired temperature.

[0024] The supercharger 7, in detail, comprises a left supercharger 7L located on the left side of the engine 100 and a right supercharger 7R located on the right side of the engine 100. The left supercharger 7L supplies air (intake) to the left intake manifold 5L via the intercooler 8. The right supercharger 7R supplies air (intake) to the right intake manifold 5R via the intercooler 8. The exhaust gas collected in the left exhaust manifold 6L is exhausted to the outside via the left supercharger 7L. The exhaust gas collected in the right exhaust manifold 6R is exhausted to the outside via the right supercharger 7R.

[0025] The oil pan 2 is located below the cylinder block 11 and stores lubricating oil. The lubricating oil stored in the oil pan 2 is supplied to the various parts of the engine 100 that require lubrication.

[0026] <2. Overview of the Cooling System> Next, an overview of the cooling system of the engine 100 will be described. Figure 5 is a schematic diagram showing an overview of the cooling system of the engine 100. The cooling system shown in Figure 5 is mainly for cooling the engine body 1. In this embodiment, the supply of coolant to the intercooler 8 is performed by a separate cooling system. Also, in this embodiment, the coolant is coolant. However, the coolant may be a liquid other than water, such as antifreeze.

[0027] The second coolant pump 21 shown in Figure 5 is a pump for supplying coolant to parts of the engine 100 that require cooling, such as the cylinder block 11 and the head block 12. These parts may include the supercharger 7 and the oil cooler 32 (described later), in addition to the cylinder block 11 and head block 12. More specifically, the second coolant pump 21 is a coolant pump separate from the low-temperature water pump 18 that supplies coolant to the intercooler 8. In the cooling system shown in Figure 5, water at a higher temperature flows through the second coolant pump 21 than the coolant that cools the intercooler 8. Considering this, the second coolant pump 21 will hereafter be referred to as the high-temperature water pump 21. The high-temperature water pump 21 is driven by rotational power transmitted from the crankshaft 10 via gears. In this embodiment, the high-temperature water pump 21 is located on the front left side of the engine 100 (see Figure 2).

[0028] The high-temperature water pump 21 drives the coolant into the left bank coolant passage 22L and the right bank coolant passage 22R. The coolant flowing through the left bank coolant passage 22L cools the area around the cylinder 14 that makes up the left bank LB and the head block 12. The coolant flowing through the right bank coolant passage 22R cools the area around the cylinder 14 that makes up the right bank RB and the head block 12.

[0029] The coolant (return coolant) that has flowed through the left bank coolant passage 22L and the right bank coolant passage 22R is sent to the thermostat case 23. In this embodiment, the thermostat case 23 is located on the upper front side of the left side of the engine 100 (see Figure 1). The thermostat case 23 has a thermostat 23a inside. The thermostat 23a has the function of maintaining the temperature of the coolant near a set temperature. Specifically, due to the action of the thermostat 23a, the return coolant sent to the thermostat case 23 is sent to the coolant cooler 24 when cooling is required, and returned directly to the high-temperature water pump 21 when cooling is not required.

[0030] The coolant cooler 24 cools the return coolant. The coolant cooler 24 is a heat exchanger that cools the return coolant using heat exchange. The return coolant that has passed through the coolant cooler 24 is sent to the high-temperature water pump 21. The coolant cooler 24 may be liquid-cooled or air-cooled.

[0031] <3. Overview of the Lubrication System> Next, an overview of the lubrication system of the engine 100 will be described. Figure 6 is a schematic diagram showing an overview of the lubrication system of the engine 100. The lubrication oil pump 31 shown in Figure 6 is a pump for supplying lubricating oil to each part of the engine 100 that requires lubrication. The lubrication oil pump 31 is driven by rotational power transmitted from the crankshaft 10 via gears. Figure 6 shows only the flow of lubricating oil supplied to each part by the drive of the lubrication oil pump 31, and the flow of lubricating oil returning to the oil pan 2 is not shown. In this embodiment, the lubrication oil pump 31 is located on the front side of the engine 100. In Figure 1, the lubrication oil pump 31 is hidden and not visible because it is located inside the oil pan 2.

[0032] The lubricating oil stored in the oil pan 2 is sent to the oil cooler 32 by the drive of the lubricating oil pump 31. In this embodiment, coolant is also supplied to the oil cooler 32 from the high-temperature water pump 21. The lubricating oil supplied to the oil cooler 32 is cooled by heat exchange with the coolant. In this embodiment, the oil cooler 32 is located at the upper front of the engine 100 (see Figure 2).

[0033] In this embodiment, a portion of the lubricating oil drawn up by the lubricating oil pump 31 is sent to the centrifugal strainer 33, purified in the centrifugal strainer 33, and then returned to the oil pan 2. This allows for the purification of the oil in the oil pan 2. In this embodiment, the centrifugal strainer 33 is located on the left side of the engine 100 (see Figure 1).

[0034] The lubricating oil that has passed through the oil cooler 32 is sent to the oil filter device 34. The oil filter device 34 purifies the lubricating oil. In this embodiment, the oil filter device 34 is located on the front left side of the engine 100 (see Figure 2).

[0035] The lubricating oil purified by the oil filter device 34 is adjusted to a predetermined pressure by the pressure regulating valve 35 and sent to the main gallery 36 located in the engine body 1. The lubricating oil relieved by the pressure regulating valve 35 is returned to the oil pan 2. In this embodiment, the pressure regulating valve 35 is located on the front side of the left side of the engine 100.

[0036] More specifically, one main gallery 36 is provided for each of the left and right cylinder rows 15L and 15R. Note that in Figure 6, the two main galleries 36 are shown vertically aligned for convenience, but in reality, they are arranged horizontally. The lubricating oil sent to each main gallery 36 is distributed to the various parts of the engine body 1 that require lubrication, such as the pistons and crankshaft 10. The oil supplied from the main gallery 36 to the various parts of the engine body 1 is returned to the oil pan 2 as needed. Furthermore, the lubricating oil that passes through one of the two main galleries 36 is supplied to the supercharger 7. More specifically, the lubricating oil is supplied to the left supercharger 7L and the right supercharger 7R. The oil that passes through the other main gallery 36 is supplied to the fuel pump 4. The oil supplied to the supercharger 7 and the fuel pump 4 is returned to the oil pan 2 as needed.

[0037] <4. Gear Configuration> Next, the gear configuration of the engine 100 will be described. Figure 7 is a schematic perspective view showing the crankshaft 10 and the auxiliary equipment driven by the rotation of the crankshaft 10 of the engine 100. As shown in Figure 7, the auxiliary equipment driven by the rotation of the crankshaft 10 includes the fuel pump 4, low-temperature water pump 18, high-temperature water pump 21, and lubricating oil pump 31 mentioned above. The auxiliary equipment also includes an alternator 19. The alternator 19 is a generator that produces alternating current electricity using the rotational power generated by the rotation of the crankshaft 10. Each auxiliary piece of equipment and the crankshaft 10 are connected via gears housed in the flywheel housing 3 located at the rear of the engine 100 and in the gear case 20 located at the front of the engine 100. Details of this will be described later.

[0038] As shown in Figure 7, in this embodiment, the camshaft 51 is also driven by the drive of the crankshaft 10. The camshaft 51 extends in the front-rear direction, similar to the crankshaft 10, and is housed within the cylinder block 11. The drive (rotation) of the camshaft 51 drives the valve train (not shown), causing the intake valve and exhaust valve (not shown) of the engine 100 to open and close.

[0039] Figure 8 is a perspective view showing the schematic configuration of the crankshaft 10 of the engine 100. As shown in Figure 8, a rear crank gear 101 is mounted on the rear end of the crankshaft 10 so as not to rotate relative to the crankshaft 10. A front crank gear 102 is mounted on the front end of the crankshaft 10 so as not to rotate relative to the crankshaft 10. In other words, the engine 100 includes a first gear 101 mounted on one end of the crankshaft 10 and a second gear 102 mounted on the other end of the crankshaft 10.

[0040] At least one of the rear crank gear (first gear) 101 and the front crank gear (second gear) 102 may be a spur gear. By using spur gears, the component cost of the crank gears can be reduced, thereby controlling the manufacturing cost of the engine 100. In this embodiment, both the rear crank gear 101 and the front crank gear 102 are spur gears. The spur gear may be a high-tooth gear with a tooth height higher than that of a standard gear. At least one of the rear crank gear 101 and the front crank gear 102 may be a different gear, such as a helical gear, instead of a spur gear.

[0041] Furthermore, at least one of the rear crank gear (first gear) 101 and the front crank gear (second gear) 102 may be made of carbon steel for machine structures. By using carbon steel for machine structures, the material cost and manufacturing cost of the crank gears can be reduced, thereby suppressing the manufacturing cost of the engine 100. In this embodiment, both the rear crank gear 101 and the front crank gear 102 are made of carbon steel for machine structures. However, at least one of the rear crank gear 101 and the front crank gear 102 may be made of a material other than carbon steel for machine structures, such as chromium-molybdenum steel.

[0042] Figure 9 shows a schematic configuration of the gear arrangement at the rear of the engine 100. As shown in Figure 9, in addition to the rear crank gear 101, drive gears for driving auxiliary equipment are arranged at the rear of the engine 100. These drive gears include a fuel pump drive gear 41. The fuel pump drive gear 41 is provided on the fuel pump 4 and is attached to the drive shaft of the pump.

[0043] Furthermore, at the rear of the engine 100, in addition to the rear crank gear 101 and the drive gear, at least one idler gear is arranged. Note that the idler gear is not mandatory, and the drive gear may be configured to mesh with the rear crank gear 101. In this embodiment, there are multiple idler gears arranged at the rear of the engine 100. The multiple idler gears include a first idler gear 61 and a second idler gear 62. In this embodiment, the first idler gear 61 is configured as a two-stage gear with two spur gears arranged in the front-rear direction. The first idler gear 61 includes a large-diameter front gear 61a and a small-diameter rear gear 61b. The second idler gear 62 is composed of a single spur gear.

[0044] The first idler gear 61 meshes with both the rear crank gear 101 and the second idler gear 62. More specifically, the front gear 61a of the first idler gear 61 meshes with the rear crank gear 101. The rear gear 61b of the first idler gear 61 meshes with the second idler gear 62. The second idler gear 62 meshes with both the first idler gear 61 and the fuel pump drive gear 41.

[0045] In other words, the fuel pump drive gear 41 is connected to the rear crank gear 101 via the first idler gear 61 and the second idler gear 62. When the rear crank gear 101 rotates due to the rotation of the crankshaft 10, rotational power is transmitted to the fuel pump drive gear 41 by the first idler gear 61 and the second idler gear 62, causing the fuel pump drive gear 41 to rotate. That is, the fuel pump 4 is driven by the rotation of the crankshaft 10.

[0046] Figure 10 shows a schematic configuration of the gear arrangement at the front of the engine 100. As shown in Figure 10, in addition to the front crank gear 102, the front of the engine 100 is equipped with multiple drive gears that drive auxiliary equipment. These multiple drive gears include a low-temperature water pump drive gear 181, an alternator drive gear 191, a high-temperature water pump drive gear 211, a lubricating oil pump drive gear 311, and a camshaft drive gear 511.

[0047] The low-temperature water pump drive gear 181 is provided on the low-temperature water pump 18 and is attached to the drive shaft of the pump. The alternator drive gear 191 is provided on the alternator 19 and is attached to the drive shaft of the alternator. The high-temperature water pump drive gear 211 is provided on the high-temperature water pump 21 and is attached to the drive shaft of the pump. The lubricating oil pump drive gear 311 is provided on the lubricating oil pump 31 and is attached to the drive shaft of the pump. The camshaft drive gear 511 is attached to the front end of the camshaft 51.

[0048] Furthermore, in addition to the front crank gear 102 and multiple drive gears, multiple idler gears are arranged on the front side of the engine 100. The multiple idler gears include a third idler gear 63, a fourth idler gear 64, a fifth idler gear 65, and a sixth idler gear 66. In this embodiment, the third idler gear 63, the fourth idler gear 64, and the sixth idler gear 66 are each composed of a single spur gear. The fifth idler gear 65 is configured as a two-stage gear with two spur gears arranged in the front-rear direction. The fifth idler gear 65 includes a small-diameter front gear 65a and a large-diameter rear gear 65b.

[0049] The third idler gear 63 meshes with both the front crank gear 102 and the cryogenic water pump drive gear 181. In other words, the cryogenic water pump drive gear 181 is connected to the front crank gear 102 via the third idler gear 63. When the front crank gear 102 rotates due to the rotation of the crankshaft 10, rotational power is transmitted to the cryogenic water pump drive gear 181 by the third idler gear 63, causing the cryogenic water pump drive gear 181 to rotate. That is, the cryogenic water pump 18 is driven by the rotation of the crankshaft 10.

[0050] The fourth idler gear 64 meshes with the front crank gear 102, the alternator drive gear 191, and the high-temperature water pump drive gear 211. In other words, the alternator drive gear 191 and the high-temperature water pump drive gear 211 are connected to the front crank gear 102 via the fourth idler gear 64. When the front crank gear 102 rotates due to the rotation of the crankshaft 10, rotational power is transmitted to the alternator drive gear 191 and the high-temperature water pump drive gear 211 by the fourth idler gear 64, causing the alternator drive gear 191 and the high-temperature water pump drive gear 211 to rotate. That is, the rotation of the crankshaft 10 drives the alternator 19 and the high-temperature water pump 21.

[0051] The fifth idler gear 65 meshes with both the front crank gear 102 and the camshaft drive gear 511. Specifically, the rear gear 65b of the fifth idler gear 65 meshes with the front crank gear 102. The front gear 65a of the fifth idler gear 65 meshes with the camshaft drive gear 511. The camshaft drive gear 511 is connected to the front crank gear 102 via the fifth idler gear 65. When the front crank gear 102 rotates due to the rotation of the crankshaft 10, rotational power is transmitted to the camshaft drive gear 511 by the fifth idler gear 65, causing the camshaft drive gear 511 to rotate. In other words, the rotation of the crankshaft 10 drives the camshaft 51.

[0052] The sixth idler gear 66 meshes with both the front crank gear 102 and the lubricating oil pump drive gear 311. In other words, the lubricating oil pump drive gear 311 is connected to the front crank gear 102 via the sixth idler gear 66. When the front crank gear 102 rotates due to the rotation of the crankshaft 10, rotational power is transmitted to the lubricating oil pump drive gear 311 by the sixth idler gear 66, causing the lubricating oil pump drive gear 311 to rotate. That is, the lubricating oil pump 31 is driven by the rotation of the crankshaft 10.

[0053] As can be seen from the above, the multiple drive gears of the engine 100 are arranged separately at the rear and front of the crankshaft 10. This prevents an uneven distribution of a large load on either the rear crank gear 101 or the front crank gear 102.

[0054] Furthermore, in this embodiment, the engine 100 is equipped with a plurality of driven gears (in this embodiment, idler gears 61, 63, 64, 65, and 66) that mesh with either the rear crank gear (first gear) 101 or the front crank gear (second gear) 102. The rear crank gear (first gear) 101 meshes with the first driven gear among the plurality of driven gears that has the greatest driving torque at the engine's maximum output. The front crank gear (second gear) 102 meshes with the second driven gear among the plurality of driven gears that has the second greatest driving torque at the engine's maximum output.

[0055] Note that "maximum engine output" refers to the state where engine 100 is at its highest output. Also, the first driven gear mentioned above does not need to have the largest driving torque among the multiple driven gears when engine 100 is not at its maximum output. Similarly, the second driven gear mentioned above does not need to have the second largest driving torque among the multiple driven gears when engine 100 is not at its maximum output.

[0056] At the maximum output of the engine 100, the crank gears 101 and 102 are susceptible to large forces from the driven gears that mesh with them. In this embodiment, the top two driven gears that generate the largest driving torque at the maximum output of the engine 100 are distributed and positioned at the front and rear of the crankshaft 10. This prevents excessive load from being applied unevenly to one of the front or rear crank gears. As a result, the possibility of damage to the crank gears 101 and 102 can be reduced, and the lifespan of the crank gears 101 and 102 can be extended. In other words, according to this embodiment, the durability and reliability of the engine 100 can be improved.

[0057] Furthermore, in this embodiment, since it is possible to suppress the excessive load applied to the crank gears 101 and 102, a slight decrease in the strength level of the crank gears 101 and 102 is permissible. For this reason, the crank gears 101 and 102 can be constructed using, for example, spur gears, which are considered to have lower strength than helical gears. Alternatively, the crank gears 101 and 102 can be constructed using, for example, carbon steel for machine structures, which has lower strength than chromium-molybdenum steel.

[0058] In this embodiment, the first driven gear described above is the first idler gear 61. That is, the fuel pump 4 is driven by the first driven gear described above. In this embodiment, the fuel pump 4 can be described as a fuel supply pump, similar to an engine configured to supply fuel to a common rail. However, the present invention can also be applied to an engine that does not employ a common rail, in which case the fuel pump 4 may be a so-called fuel injection pump. As can be seen from the above, the engine may be configured such that the fuel supply pump or fuel injection pump is driven by the first driven gear described above.

[0059] Furthermore, in this embodiment, drive gears other than the fuel pump drive gear 41 that drives the fuel pump 4 are located on the front side of the engine 100. That is, the above-mentioned second driven gear meshes with the front crank gear 102. The above-mentioned second driven gear may be, for example, any of the third idler gear 63, the fourth idler gear 64, and the sixth idler gear 66. That is, the above-mentioned second driven gear may be configured to drive any of the low-temperature water pump 18, the high-temperature water pump 21, and the lubricating oil pump 31. Note that the low-temperature water pump 18 and the high-temperature water pump 21 are examples of coolant pumps. Also, the coolant pump and the lubricating oil pump may be configured to be driven by the same idler gear. As can be seen from the above, the engine may be configured so that at least one of the coolant pump and the lubricating oil pump is driven by the above-mentioned second driven gear.

[0060] Furthermore, although the above description assumes that the only gear meshing with the first gear 101 is the first driven gear described above, this is merely an example. The first gear 101 may mesh with gears other than the second driven gear described above, in addition to the first driven gear described above. In other words, auxiliary equipment other than the fuel pump 4 may be located at the rear of the engine 100. Also, although the above description assumes that the first gear 101 is located at the rear of the engine 100 and the second gear 102 is located at the front of the engine 100, this is merely an example. In other words, the first gear may be located at the front of the engine and the second gear may be located at the rear of the engine.

[0061] Furthermore, the configurations shown above are merely examples regarding the number and types of auxiliary equipment driven by the crankshaft 10. The number and types of auxiliary equipment driven by the crankshaft 10 may be different from those shown above.

[0062] For example, although the number of fuel pumps 4 is assumed to be one in the above example, the number of fuel pumps 4 may be multiple. In this case, for example, as shown in Figure 11, the number of fuel pump drive gears 41 that mesh with the second idler gear 62 may be multiple. In the example shown in Figure 11, it is assumed that there are two fuel pumps 4, and the first fuel pump drive gear 41A and the second fuel pump drive gear 41B mesh with the second idler gear 62.

[0063] Furthermore, for example, if the engine is a marine engine, the engine may be configured to include a seawater pump driven by the crankshaft 10. In this case, for example, as shown in Figure 12, the third idler gear 63 may be configured to mesh with the seawater pump drive gear 71 in addition to the low-temperature water pump drive gear 181. The seawater pump may be a pump for supplying seawater to a heat exchanger that cools the aforementioned coolant (high-temperature water or low-temperature water) using heat exchange with seawater.

[0064] <5. Points to note> Various technical features disclosed herein can be modified in various ways without departing from the spirit of the technical creation. In other words, the embodiments described above should be considered in all respects to be illustrative and not restrictive. Furthermore, the multiple embodiments and modifications shown herein may be combined as possible.

[0065] In the embodiments described above, the present invention is configured to be applied to a V-type engine. However, this is merely illustrative. The present invention is broadly applicable to other engines, such as in-line engines in which the pistons reciprocate in the vertical direction, and horizontally opposed engines in which the pistons reciprocate in the horizontal direction.

[0066] <6. Addendum> An exemplary engine as described herein comprises a crankshaft, a first gear attached to one end of the crankshaft, a second gear attached to the other end of the crankshaft, and a plurality of driven gears that mesh with either the first gear or the second gear, wherein the first gear meshes with the first driven gear having the greatest driving torque at the engine's maximum output, and the second gear meshes with the second driven gear having the second greatest driving torque at the engine's maximum output (first configuration).

[0067] The engine in the first configuration described above may be configured such that a fuel supply pump or a fuel injection pump is driven by the first driven gear (second configuration).

[0068] The engine of the first or second configuration described above may be configured such that at least one of the coolant pump and the lubricating oil pump is driven by the second driven gear (third configuration).

[0069] In an engine with any of the first to third configurations described above, at least one of the first gear and the second gear may be a spur gear (fourth configuration).

[0070] In an engine with any of the first to fourth configurations described above, at least one of the first gear and the second gear may be made of carbon steel material for machine structures (fifth configuration). [Explanation of Symbols]

[0071] 4. Fuel pump 10. Crankshaft 18. Low-temperature water pump 21. High-temperature water pump 31. Lubrication oil pump 61...1st Idler Gear 63...3rd Idol Gear 64...4th Idol Gear 66...6th Idol Gear 100... Engine 101...Rear crank gear 102...Front crank gear

Claims

1. Crank axle and, A first gear attached to one end of the crankshaft, A second gear is attached to the other end of the crankshaft, A plurality of driven gears, three or more of which mesh with either the first gear or the second gear, Equipped with, The first gear meshes with the first driven gear among the plurality of driven gears that has the greatest driving torque at the engine's maximum output, The engine wherein the second gear meshes with the second driven gear among the plurality of driven gears that has the second largest driving torque at the engine's maximum output.

2. The engine according to claim 1, wherein the first driven gear drives a fuel supply pump or a fuel injection pump.

3. The engine according to claim 1, wherein at least one of the coolant pump and the lubricating oil pump is driven by the second driven gear.

4. The engine according to any one of claims 1 to 3, wherein at least one of the first gear and the second gear is a spur gear.

5. The engine according to any one of claims 1 to 3, wherein at least one of the first gear and the second gear is made of carbon steel material for machine structures.

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