Engine arrangement

Abstract

The engine device according to the present invention includes: a common rail; and a fuel return pipe connected to the common rail and causing fuel in the injector to return to the common rail, the fuel return pipe being connected to one end of the common rail.

Description

[0001] This application is a divisional application of the invention patent application with application number 201780086673.5 (international application number PCT / JP2017 / 042862), application date November 29, 2017, entitled "Engine Device". Technical Field

[0002] This invention relates to an engine device with a common rail. Background Technology

[0003] In recent years, common rail systems have been increasingly used in diesel engines due to the need for higher injection pressures to meet exhaust emission restrictions and reduce fuel consumption requirements (see, for example, Patent Documents 1 and 2). The common rail stores fuel supplied from the fuel tank at high pressure. The pressure within the common rail is regulated by a pressure-reducing valve installed on it. Fuel discharged from the pressure-reducing valve returns to the fuel tank via a fuel return pipe (also known as a leak pipe) connected to the valve.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent No. 4074860

[0007] Patent Document 2: Japanese Patent Application Publication No. 2007-139098 Summary of the Invention

[0008] Furthermore, in common rail systems, fuel is used to lubricate the sliding portion of the pressure-reducing valve. Conventionally, to ensure the sliding portion of the pressure-reducing valve is immersed in fuel, the mounting angle (the protruding direction of the fuel return pipe connection) of the common rail when mounted on the engine unit is ensured to be within a range of 45 degrees to 90 degrees from horizontal to upward. Additionally, when this mounting angle is within the range of 0 degrees to 45 degrees, the fuel return pipe is mounted upwards at the fuel return pipe connection. This results in limitations on the connection direction of the fuel return pipe to the common rail and limitations on the mounting conditions of the common rail.

[0009] The present invention addresses the current state of affairs as described above, with the technical problem of providing an improved engine device.

[0010] The engine device of this invention includes a common rail, which stores fuel supplied from a fuel supply pump at high pressure. In this engine device, the common rail includes a pressure reducing valve for discharging fuel from the common rail into a fuel return pipe. The fuel return pipe is guided from the pressure reducing valve to a position higher than the pressure reducing valve, and then guided to a position lower than the pressure reducing valve.

[0011] In the engine device of this invention, the engine device can be a structure in which an exhaust gas recirculation device is connected to an intake manifold provided in the cylinder head. The exhaust gas recirculation device is used to mix a portion of the exhaust gas discharged from the exhaust manifold into fresh gas. The common rail is arranged below the intake manifold, and the middle part of the fuel return pipe is installed on the exhaust gas recirculation device at a position higher than the pressure reducing valve.

[0012] Furthermore, it can be that a fuel injection pipe extending from the common rail towards the cylinder head passes between the cylinder head and the exhaust gas recirculation device.

[0013] The engine device of this invention includes a common rail, which stores fuel supplied from a fuel supply pump at high pressure. In this engine device, the common rail has a pressure-reducing valve that discharges fuel from the common rail to a fuel return pipe. The fuel return pipe is guided from a position higher than the pressure-reducing valve to a position lower than the pressure-reducing valve. Therefore, regardless of the mounting angle of the common rail or the connection direction of the fuel return pipe, fuel can be stored between the fuel return pipe portion (higher than the pressure-reducing valve) and the pressure-reducing valve, ensuring that the pressure-reducing valve is immersed in fuel and preventing abnormal wear of the sliding portion of the pressure-reducing valve. This relaxes the mounting conditions of the common rail, thereby increasing the design freedom of the engine device.

[0014] Furthermore, in the engine device of this invention, if the engine device is a structure in which an exhaust gas recirculation device is connected to an intake manifold located in the cylinder head, and the exhaust gas recirculation device is used to mix a portion of the exhaust gas discharged from the exhaust manifold into fresh gas, and the common rail is positioned below the intake manifold, with the middle section of the fuel return pipe installed in the exhaust gas recirculation device at a position higher than the pressure relief valve, then there is no need to provide a dedicated component in the engine device for supporting the middle section of the fuel return pipe, thus suppressing the increase in the manufacturing cost of the engine device. In addition, by arranging the common rail below the high-rigidity intake manifold, the common rail can be compactly arranged, and foreign objects can be prevented from contacting the common rail from above, thereby physically protecting the common rail.

[0015] Furthermore, if the fuel injection pipe extending from the common rail towards the cylinder head passes between the cylinder head and the exhaust gas recirculation (EGR) device, the EGR device can protect the fuel injection pipe. Therefore, during engine handling, deformation of the fuel injection pipe due to contact with other components or falling foreign objects can be prevented, and adverse conditions such as fuel leakage due to damage to the fuel injection pipe can be eliminated. Attached Figure Description

[0016] Figure 1 This is a schematic front view of one embodiment of the engine device.

[0017] Figure 2 This is a schematic rear view of the above-described embodiment.

[0018] Figure 3 This is a schematic left view of the above-described embodiment.

[0019] Figure 4 This is a schematic right view of the above-described embodiment.

[0020] Figure 5 This is a schematic top view of the above-described embodiment.

[0021] Figure 6 This is an explanatory diagram of the fuel system according to the above-described embodiment.

[0022] Figure 7 This is a schematic front view showing the enlarged common rail perimeter of the above-described embodiment.

[0023] Figure 8 This is a schematic left view showing the enlarged perimeter of the aforementioned common track.

[0024] Figure 9 This is a schematic top view showing the enlarged perimeter of the aforementioned common rail.

[0025] Figure 10 yes Figure 9 A schematic rear view of the above embodiment at position A-A.

[0026] Figure 11 This is a schematic front view showing the enlarged periphery of the right front corner of the above embodiment.

[0027] Figure 12 This is a schematic top view showing the enlarged periphery of the right front corner of the above embodiment.

[0028] Figure 13 This is a schematic perspective view showing the enlarged periphery of the right front corner of the above embodiment.

[0029] Figure 14 This is a schematic rear view of another embodiment. Detailed Implementation

[0030] Hereinafter, embodiments embodying the present invention will be described with reference to the accompanying drawings. First, referring to... Figures 1-5The overall structure of engine 1, which is an example of an engine unit, will be described. In this embodiment, engine 1 is a diesel engine. Furthermore, in the following description, for engine 1, the two sides parallel to the crankshaft 5 (the sides sandwiching the two sides of the crankshaft 5) are referred to as left and right, the side where the flywheel housing 7 is located is referred to as the front side, and the side where the cooling fan 9 is located is referred to as the rear side. For ease of explanation, these will be used as the reference for the positional relationship of engine 1 around its perimeter and vertically.

[0031] like Figures 1-5 As shown, an intake manifold 3 is disposed on one side of the engine 1 parallel to the crankshaft 5, and an exhaust manifold 4 is disposed on the other side. In this embodiment, the intake manifold 3 is integrally formed with the cylinder head 2 on the right side. The exhaust manifold 4 is disposed on the left side of the cylinder head 2. The cylinder head 2 is mounted on a cylinder block 6, which houses the crankshaft 5 and pistons (not shown).

[0032] The front and rear ends of the crankshaft 5 protrude from the front and rear sides of the cylinder block 6. A flywheel housing 7 is fixedly mounted on one side of the engine 1 that intersects with the crankshaft 5 (in this embodiment, the front side of the cylinder block 6). A flywheel 8 is disposed within the flywheel housing 7. The flywheel 8 is configured to be fixedly mounted on the front end of the crankshaft 5 and rotate integrally with the crankshaft 5. The configuration is such that power from the engine 1 is extracted to the working part of a work machine (e.g., a hydraulic excavator, forklift, etc.) via the flywheel 8. A cooling fan 9 is provided on the other side of the engine 1 that intersects with the crankshaft 5 (in this embodiment, the rear side of the cylinder block 6). The configuration is such that rotational force is transmitted from the rear end of the crankshaft 5 to the cooling fan 9 via a belt 10.

[0033] An oil pan 11 is disposed on the lower surface of the cylinder block 6. Lubricating oil accumulates in the oil pan 11. The lubricating oil in the oil pan 11 is drawn by a lubricating oil pump (not shown) and supplied to the various lubrication parts of the engine 1 via an oil cooler 13 and an oil filter 14 disposed on the right side of the cylinder block 6. The lubricating oil pump is disposed at the connection between the cylinder block 6 and the flywheel housing 7 and is disposed on the right side of the cylinder block 6. The lubricating oil supplied to the various lubrication parts then returns to the oil pan 11. The lubricating oil pump is configured to be driven by the rotation of the crankshaft 5.

[0034] like Figure 4As shown, a fuel supply pump 15 for supplying fuel is installed on the right side of the engine 1 at the connection between the cylinder block 6 and the flywheel housing 7. The fuel supply pump 15 is positioned below the EGR (Exhaust Gas Recirculation) device 24. Furthermore, a common rail 16 is arranged between the intake manifold 3 of the cylinder head 2 and the fuel supply pump 15. The common rail 16 is fixed to the upper front part of the right side of the cylinder block 6. On the upper surface of the cylinder head 2, covered by the cylinder head cover 18, injectors 17 corresponding to each of the four cylinders are provided (see reference). Figure 6 ).

[0035] Each injector 17 is connected to the fuel tank 201 mounted on the work vehicle (see reference) via a fuel supply pump 15 and a generally cylindrical common rail 16. Figure 6 The fuel in the fuel tank 201 is pumped from the fuel supply pump 15 to the common rail 16, whereby high-pressure fuel is stored. By controlling the opening and closing of the fuel injection valves of each injector 17, the high-pressure fuel in the common rail 16 is injected from each injector 17 into each cylinder of the engine 1.

[0036] like Figure 2 as well as Figure 5 As shown, a blowby gas reversal device 19 is provided on the upper surface of the cylinder head cover 18. The cylinder head cover 18 is used to cover the intake valves and exhaust valves (not shown) located on the upper surface of the cylinder head 2. The blowby gas reversal device 19 is used to take in the blowby gas mixture that leaks from the combustion chamber of the engine 1 to the upper surface of the cylinder head 2. The blowby gas mixture outlet of the blowby gas reversal device 19 is connected to the intake section of the secondary turbocharger 30 via a reversal hose 68. The blowby gas mixture, after the lubricating oil components have been removed in the blowby gas reversal device 19, returns to the intake manifold 3 via the secondary turbocharger 30, etc.

[0037] like Figure 3 As shown, an engine starter motor 20 is installed on the flywheel housing 7 on the left side of the engine 1. The engine starter motor 20 is located below the exhaust manifold 4. The engine starter motor 20 is installed below the connection between the cylinder block 6 and the flywheel housing 7, and on the left side of the rear side of the flywheel housing 7.

[0038] like Figure 2As shown, a cooling water pump 21 for lubrication is located on the left side of the rear side of the cylinder block 6. Additionally, an alternator 12, which generates electricity using power from the engine 1, is located to the left of the cooling water pump 21. Rotational power is transmitted from the front end of the crankshaft 5 via belt 10 to the cooling fan 9, alternator 12, and cooling water pump 21. Coolant from the radiator (not shown) of the work vehicle is supplied to the cooling water pump 21 by its drive. The coolant is then supplied to the cylinder head 2 and cylinder block 6 to cool the engine 1.

[0039] like Figure 3 As shown, the cooling water pump 21 is positioned below the height of the exhaust manifold 4, and the cooling water inlet pipe 22, which communicates with the cooling water outlet of the radiator, is fixed to the left side of the cylinder block 6 and positioned at approximately the same height as the cooling water pump 21. On the other hand, as... Figure 2 as well as Figure 5 As shown, a cooling water outlet pipe 23, which is connected to the cooling water inlet of the radiator, is fixed to the rear right part of the upper surface of the cylinder head 2. The cylinder head 2 has a cooling water drain section 35 at its right rear corner, and a cooling water outlet pipe 23 is provided on the upper surface of the cooling water drain section 35.

[0040] like Figure 4 as well as Figure 5 As shown, the EGR device 24 is located on the right side of the cylinder head 2. The EGR device 24 includes: a collector 25 serving as a relay pipe, which mixes the recirculated exhaust gas (EGR gas from the exhaust manifold 4) of the engine 1 with fresh gas (outdoor air from the air purifier) ​​and supplies it to the intake manifold 3; an intake throttle valve assembly 26, which connects the collector 25 to the air purifier; a recirculated exhaust gas pipe 28, which is part of a return pipe connected to the exhaust manifold 4 via the EGR cooler 27; and an EGR valve assembly 29, which connects the collector 25 to the recirculated exhaust gas pipe 28.

[0041] In this embodiment, the collector 25 of the EGR device 24 is connected to the right side of the intake manifold 3, which is integrally formed with the cylinder head 2 and constitutes the right side of the cylinder head 2. That is, the outlet opening of the collector 25 is connected to the inlet opening of the intake manifold 3 located on the right side of the cylinder head 2. In addition, the EGR gas inlet of the recirculation exhaust gas pipe 28 is connected to the EGR gas outlet of the EGR gas passage located in the cylinder head 2 at a forward position on the right side of the cylinder head 2. The collector 25 is installed on the intake manifold 3 and the recirculation exhaust gas pipe 28 is installed on the cylinder head 2, thereby fixing the EGR device 24 to the cylinder head 2.

[0042] In the EGR unit 24, the intake manifold 3 is connected to the intake throttle valve assembly 26 for introducing fresh gas via the collector 25. The EGR valve assembly 29, connected to the outlet side of the recirculated exhaust gas pipe 28, is also connected to the collector 25. The collector 25 is formed as a generally cylindrical shape with a longitudinal dimension. The intake throttle valve assembly 26 is fastened to the gas intake side (front side in the longitudinal direction) of the collector 25 by bolts. The gas discharge side of the collector 25 is fastened to the inlet side of the intake manifold 3 by bolts. Furthermore, the EGR valve assembly 29 regulates the amount of EGR gas supplied to the collector 25 by adjusting the opening degree of the EGR valve located inside it.

[0043] Fresh gas is supplied to collector 25, and EGR gas (a portion of the exhaust gas discharged from exhaust manifold 4) is supplied to collector 25 from exhaust manifold 4 via EGR valve component 29. After the fresh gas and EGR gas from exhaust manifold 4 are mixed in collector 25, the mixture in collector 25 is supplied to intake manifold 3. That is, a portion of the exhaust gas discharged from engine 1 to exhaust manifold 4 returns to engine 1 from intake manifold 3, thereby reducing the maximum combustion temperature during high-load operation and reducing the emission of NOx (nitrogen oxides) from engine 1.

[0044] like Figure 1 as well as Figures 3-5 As shown, the EGR cooler 27 is fixed to the front side of the cylinder head 2. Cooling water and EGR gas flowing inside the cylinder head 2 flow in and out relative to the EGR cooler 27, and the EGR gas is cooled inside the EGR cooler 27. A pair of left and right EGR cooler connecting parts 33 and 34 are protruding from the front side of the cylinder head 2 for connecting the EGR cooler 27. The left EGR cooler connecting part 33 protrudes forward at the left front corner of the cylinder head 2. The right EGR cooler connecting part 34 is separate from the left EGR cooler connecting part 33 and protrudes forward at the right front corner of the cylinder head 2. Furthermore, the EGR cooler 27 is connected to the front side of the EGR cooler connecting parts 33 and 34. That is, the EGR cooler 27 is positioned above the flywheel housing 7 and in front of the cylinder head 2 in a manner that separates the rear side of the EGR cooler 27 from the front side of the cylinder head 2.

[0045] like Figures 1-3 as well as Figure 5As shown, a two-stage turbocharger 30 is arranged on the left side of the cylinder head 2. The two-stage turbocharger 30 includes a high-pressure stage turbocharger 51 and a low-pressure stage turbocharger 52. The high-pressure stage turbocharger 51 has a high-pressure stage turbine housing 53 with a built-in turbine wheel (not shown) and a high-pressure stage compressor housing 54 with a built-in blower wheel (not shown). The low-pressure stage turbocharger 52 has a low-pressure stage turbine housing 55 with a built-in turbine wheel (not shown) and a low-pressure stage compressor housing 56 with a built-in blower wheel (not shown).

[0046] In the exhaust path of the second-stage turbocharger 30, the high-pressure stage turbine housing 53 is connected to the exhaust manifold 4, the low-pressure stage turbine housing 55 is connected to the high-pressure stage turbine housing 53 via a high-pressure exhaust gas pipe 59, and the exhaust connecting pipe 119 is connected to the low-pressure stage turbine housing 55. The high-pressure exhaust gas pipe 59 is formed of a flexible pipe. In this embodiment, a portion of the high-pressure exhaust gas pipe 59 is formed in a serpentine shape.

[0047] The tailpipe (not shown) is connected to the exhaust manifold 119 via an exhaust gas purification device (not shown). The exhaust gas discharged from each cylinder of the engine 1 to the exhaust manifold 4 passes through the secondary turbocharger 30 and the exhaust gas purification device and is discharged to the outside through the tailpipe.

[0048] In the intake path of the secondary turbocharger 30, the low-pressure stage compressor housing 56 is connected to the air purifier via the air supply pipe 62, and the high-pressure stage compressor housing 54 is connected to the low-pressure stage compressor housing 56 via the low-pressure fresh gas passage pipe 65. The intake throttle valve component 26 of the EGR device 24 is connected to the high-pressure stage compressor housing 54 via the intercooler (not shown). The fresh gas (outdoor air) drawn into the air purifier is dusted and purified by the air purifier, and then sent to the intake manifold 3 via the secondary turbocharger 30, intercooler, intake throttle valve component 26, collector 25, etc., and then supplied to each cylinder of the engine 1.

[0049] Next, refer to Figure 6 The fuel system structure of the common rail system 200 and engine 1 will be described. The fuel tank 201 is connected to each of the four injectors 17 located in the engine 1, corresponding to each of the four cylinders, via a fuel supply pump 15 and the common rail system 200. Each injector 17 has an electromagnetically controlled fuel injection valve 17a. The common rail system 200 has a generally cylindrical common rail 16.

[0050] The fuel tank 201 is connected to the suction side of the fuel supply pump 15 via the fuel supply pipe 210, the fuel filter 202, and the low-pressure fuel supply pipe 203. On the other hand, the common rail 16 is connected to the discharge side of the fuel supply pump 15 via the high-pressure fuel supply pipe 204. A high-pressure pipe connection 205 is provided at one end of the common rail 16 near its longitudinal direction. The end of the high-pressure fuel supply pipe 204 is connected to the high-pressure pipe connection 205 by screwing on a high-pressure pipe connector nut 206. Fuel in the fuel tank 201 is drawn into the fuel supply pump 15 via the fuel filter 202 and the low-pressure fuel supply pipe 203, and then pumped from the fuel supply pump 15 to the common rail 16 via the high-pressure fuel supply pipe 204.

[0051] Furthermore, each injector 17 corresponding to one of the four cylinders is connected to the common rail 16 via four fuel injection pipes 207. Along the longitudinal direction of the cylindrical common rail 16, fuel injection pipe connectors 208 corresponding to the four cylinders are spaced apart. The ends of the fuel injection pipes 207 are connected to the fuel injection pipe connectors 208 by screwing in the fuel injection pipe connector nuts 209.

[0052] A pressure-reducing valve 211 is installed on the end face of the common rail 16 opposite to the aforementioned end. The pressure-reducing valve 211 discharges fuel from the common rail 16 through the fuel return pipe connection 212 located on the outer circumference of the common rail 16 to the common rail residual fuel return pipe 214 via the fuel return pipe connection component 213. The common rail residual fuel return pipe 214 connects the fuel return pipe connection component 213 to the return pipe connector component 215, which discharges residual fuel from the fuel supply pump 15.

[0053] A return pipe connector component 216 for residual fuel return is provided on one end face of the common rail 16. Fuel discharged from the common rail 16 by the operation of the pressure reducing valve 211 and residual fuel from the fuel supply pump 15 are sent to the return pipe connector component 216 via the return pipe connector component 215 and the pump residual fuel return pipe 217. Additionally, regarding the return pipe connector component 216, residual fuel from each injector 17 is sent to the return pipe connector component 216 via the injector residual fuel return pipe 218. The residual fuel converging in the return pipe connector component 216 is recovered to the fuel tank 201 via the fuel return pipe 219. Although in Figure 6 The diagram is omitted, but the middle part of the fuel return pipe 219 and the return pipe connection part 220 provided above the fuel filter 202 (see reference) are shown. Figure 12 )connect.

[0054] A fuel pressure sensor 601 is installed in the common rail 16 to detect the fuel pressure within the common rail 16. Under the control of the engine controller 600, the opening degree of the intake regulating valve 602 of the fuel supply pump 15 is adjusted while monitoring the fuel pressure within the common rail 16 based on the output of the fuel pressure sensor 601. Furthermore, while adjusting the fuel intake amount of the fuel supply pump 15, and thus the fuel injection amount, the fuel is pressurized from the fuel tank 201 to the common rail 16 via the fuel supply pump 15, and the high-pressure fuel is stored in the common rail 16.

[0055] Under the control of the engine controller 600, each fuel injection valve 17a is individually switched on and off, thereby injecting high-pressure fuel from the common rail 16 into each cylinder of the engine 1 from each injector 17. That is, by electronically controlling each fuel injection valve 17a, the injection pressure, injection timing, and injection duration (injection quantity) of the fuel supplied from each injector 17 can be controlled with high precision. Therefore, nitrogen oxides (NOx) emitted from the engine 1 can be reduced, and engine noise and vibration can be reduced. Furthermore, the engine controller 600 is electrically connected to: an electromagnetically driven pressure reducing valve 211 for regulating fuel pressure within the common rail 16, and a fuel temperature sensor 604 for detecting fuel temperature within the fuel supply pump 15. Additionally, although not shown in the figures, other devices, such as various sensors installed in the engine 1, are also electrically connected to the engine controller 600.

[0056] Next, refer to Figures 7-13 The layout of the common rail 16 is described below. The roughly cylindrical common rail 16 extends along its longitudinal dimension along the crankshaft 5 (see reference 5). Figure 1 The common rail 16 is mounted on the upper front part of the right side of the cylinder block 6 in an axial direction. The common rail 16 is positioned below the intake manifold 3, which is integrally formed with the cylinder head 2 on the right side. A pressure reducing valve 211 is installed at the rear end of the common rail 16.

[0057] The following components protrude from the right side of the outer peripheral surface of the common rail 16: a high-pressure pipe connection 205, four fuel injection pipe connections 208, and a fuel return pipe connection 212. These connections 205, 208, and 212 protrude to the right and, in this embodiment, are generally horizontally positioned. That is, in this embodiment, the common rail 16 is mounted to the engine 1 at a 0-degree mounting angle. The high-pressure pipe connection 205 is located at the front of the common rail 16. The fuel return pipe connection 212 is located at the rear of the common rail 16. The four fuel injection pipe connections 208 are evenly spaced between the fuel return pipe connections 212.

[0058] like Figure 10As shown, one end of the common rail residual fuel return pipe 214 (the upstream end of the fuel flow) is connected to the fuel return pipe connection portion 212 via the fuel return pipe connection member 213. After being horizontally guided to the right from the fuel return pipe connection portion 212, the fuel return pipe 214 bends obliquely upward to the right and is guided to a position higher than the pressure reducing valve 211. In this embodiment, the fuel return pipe 214 is guided near the lower front portion of the collector 25 of the EGR device 24 and is installed at the lower right corner of the back side of the front flange 25a of the collector 25 via the piping installation member 221. Further, the fuel return pipe 214 bends obliquely downward from the lower front portion of the collector 25 and connects to the return pipe connector member 215 provided on the right side of the fuel supply pump 15. In addition, the fuel return pipe connection member 213 is installed on the fuel return pipe connection portion 212 in a manner that protrudes substantially horizontally to the right from the fuel return pipe connection portion 212.

[0059] In this embodiment, the common rail residual fuel return pipe 214 is guided to a position lower than the pressure reducing valve 211 after being guided from the pressure reducing valve 211 to a position higher than the pressure reducing valve 211. Therefore, regardless of the mounting angle of the common rail 16 or the connection direction of the fuel return pipe 214 to the common rail 16, fuel can accumulate between the portion of the fuel return pipe 214 at the position higher than the pressure reducing valve 211 and the pressure reducing valve 211. This ensures that the pressure reducing valve 211 is immersed in fuel, preventing abnormal wear of the sliding portion of the pressure reducing valve 211. Furthermore, the mounting conditions of the common rail 16 are relaxed, thereby increasing the design freedom of the engine 1.

[0060] Furthermore, the middle section of the fuel return pipe 214 is mounted on the collector 25 of the EGR device 24 at a position higher than the pressure reducing valve 211. Therefore, there is no need to install a dedicated component in the engine 1 to support the middle section of the fuel return pipe 214, which can suppress the increase in the manufacturing cost of the engine 1. In addition, by arranging the common rail 16 below the high-rigidity intake manifold 3, the common rail 16 can be arranged compactly, and foreign objects can be prevented from contacting the common rail 16 from above, thereby physically protecting the common rail 16.

[0061] like Figures 7-10As shown, the front end of the common rail 16 is mounted on the flywheel housing 7. A return pipe connector component 216 for merging multiple fuel return paths is installed at the front end of the common rail 16. The return pipe connector component 216 is mounted on the flywheel housing 7. By positioning one end (the front end) of the common rail 16 above the flywheel housing 7, compared to a structure where the common rail 16 is entirely positioned on the right side of the cylinder block 6, the area occupied by the common rail 16 on the right side of the cylinder block 6 is reduced. Therefore, the flexibility in the layout of other components on the right side of the cylinder block 6 can be increased. For example, in the engine 1 of this embodiment, an oil cooler 13 is positioned behind the common rail 16 and close to the intake manifold 3 and the EGR device 24, thereby enabling a compact configuration of these components.

[0062] like Figure 7 As shown, the return pipe connector component 216 includes: a connecting portion 217a, which connects to one end of the pump residual fuel return pipe 217; a connecting portion 218a, which connects to one end of the injector residual fuel return pipe 218; and a connecting portion 219a, which connects to the fuel return pipe 219 (see reference). Figure 12 One end of the return pipe connector component 216 is provided with: an internal flow path (not shown) that connects the connecting parts 217a, 218a, and 219a; and a fuel pressure regulating valve (not shown) that is disposed between the internal flow path and the internal space of the common rail 16.

[0063] Additionally, in cylinder head 2, near the corner where the right side of cylinder head 2 intersects with the front side, a residual fuel outlet 218b is provided (see reference). Figure 7 The residual fuel outlet 218b is located on the upper part of the front end of the right side of the cylinder head 2, forming part of the injector residual fuel return pipe 218. The residual fuel outlet 218b receives fuel from the injector 17 (see reference 17) located within the cylinder head 2. Figure 6 The remaining fuel is discharged outside the cylinder head 2. A residual fuel return pipe 218c is connected between the residual fuel outlet 218b and the connection portion 218a of the return pipe connector component 216. Furthermore, the residual fuel outlet 218b connects to each injector 17 (see reference 1) via a residual fuel passage (not shown) formed inside the side wall of the cylinder head 2. Figure 6 The remaining fuel outlet 218b is connected.

[0064] like Figures 7-10As shown, four fuel injection pipes 207, mounted on the four fuel injection pipe connectors 208 via injection pipe connector nuts 209, are horizontally guided from the fuel injection pipe connectors 208 to the right below the EGR device 24. Furthermore, each fuel injection pipe 207 bends downwards towards the cylinder block 6 below the EGR device 24, then bends upwards, passing between the cylinder head 2 and the EGR device 24 and being guided to the right side of the cylinder head cover 18. Figure 8 , Figure 9 and Figure 13 As shown, the middle sections of the four fuel injection pipes 207 are mounted to the cylinder head 2 by a pair of fuel injection pipe fasteners 614, 614 installed on the right side of the cylinder head 2.

[0065] Two fuel injection pipes 207 are fixed to each of the fuel injection pipe fixing members 614, 614 respectively. The middle portion of each of the two fuel injection pipes 207 on the front side of the engine 1 is fixed to the end face of the protrusion 615 by the front fuel injection pipe fixing member 614. The protrusion 615 is located in front of the intake manifold 3 and protrudes to the right side of the cylinder head 2. The middle portion of each of the two fuel injection pipes 207 on the rear side of the engine 1 is fixed to the right side of the intake manifold 3, which is integrally formed with the right side of the cylinder head 2, by the rear fuel injection pipe fixing member 614.

[0066] Each fuel injection pipe 207 passes between the cylinder head 2 and the EGR device 24, thus the fuel injection pipe 207 can be protected by the EGR device 24. Therefore, when transporting the engine 1, the fuel injection pipe 207 can be prevented from contacting other components or from deforming due to falling foreign objects, and adverse conditions such as fuel leakage due to damage to the fuel injection pipe 207 can be prevented.

[0067] Furthermore, the middle section of the fuel injection pipe 207 is fixed to the cylinder head 2, thereby reducing vibration of the fuel injection pipe 207 and preventing damage to the fuel injection pipe 207 due to vibration. In this embodiment, the middle sections of the two fuel injection pipes 207 located at the rear of the engine 1 are fixed to the robust intake manifold 3 using the rear fuel injection pipe fixing member 614, thus ensuring a secure fixation of these fuel injection pipes 207. In this embodiment, since the intake manifold 3 and cylinder head 2 are integrally formed, the fuel injection pipes 207 can be fixed even more securely.

[0068] like Figures 7-10As shown, one end of the high-pressure fuel supply pipe 204, which is connected to the common rail 16, is attached to the upper right side of the fuel supply pump 15. After being guided to the right from the upper right side of the fuel supply pump 15, the high-pressure fuel supply pipe 204 bends forward and upward, and then bends towards the upper front part of the right side of the cylinder block 6. Furthermore, the high-pressure fuel supply pipe 204 passes below the EGR device 24 and is guided to the high-pressure pipe connection portion 205 of the common rail 16. The other end of the high-pressure fuel supply pipe 204 is connected to the high-pressure pipe connection portion 205 via a high-pressure pipe connector nut 206.

[0069] The high-pressure fuel supply pipe 204, the four fuel injection pipes 207, and the common rail residual fuel return pipe 214 pass below the EGR device 24, thus being protected by the EGR device 24 from contact with foreign objects from above. This reduces the risk of damage to the high-pressure fuel supply pipe 204, the fuel injection pipes 207, and the fuel return pipe 214, improving the reliability of the engine 1.

[0070] like Figures 7-10 As shown, the high-pressure pipe connection 205, the four fuel injection pipe connections 208, and the fuel return pipe connection 212 protrude approximately horizontally to the right from the right side of the outer peripheral surface of the common rail 16. Furthermore, no connections for connecting piping are provided on the upper part or the left side of the outer peripheral surface of the common rail 16. Therefore, the common rail 16 can be positioned close to the lower surface of the intake manifold 3 and the right side of the cylinder block 6, the common rail 16 can be protected by the intake manifold 3, and the common rail 16 can be compactly positioned within the engine 1.

[0071] like Figure 5 as well as Figures 11-13 As shown, a fuel filter 202 is provided at the upper right front part of the engine 1. The fuel filter 202 is positioned above the right side of the flywheel housing 7 and is mounted on the right front corner of the cylinder head 2 via a filter mounting bracket 231. By arranging the fuel filter 202 in the unused space above the flywheel housing 7, the fuel filter 202 can be compactly arranged in the engine 1, thus achieving a compact engine 1.

[0072] The upper left edge of the fuel filter 202 is fixed to the upper front right part of the filter mounting bracket 231 using two bolts 232 and 233. The filter mounting bracket 231 is secured to the upper front right part of the filter mounting bracket 231 using bolt mounting holes 234a and 235a (see reference) on the upper surface of the right EGR cooler connection part 34. Figure 9 Bolts 234 and 235, and bolt mounting holes 236a on the front side of the right edge portion 34a of the right EGR cooler connection 34 (see reference). Figure 7The filter is fixed to the right EGR cooler connection 34 by bolts 2346. By fixing the filter mounting bracket 231 to the upper surface and front side of the right EGR cooler connection 34 of the cylinder block 6, the filter mounting bracket 231 can be firmly fixed to the cylinder block 6, and the fuel filter 202 can be firmly fixed to the cylinder block 6.

[0073] like Figures 11-13 As shown, the return pipe connector component 215, located on the right side of the fuel supply pump 15, is connected to the connecting portion 217a of the return pipe connector portion 216 mounted on the front end of the common rail 16 via the pump residual fuel return pipe 217. The connecting portion 218a of the return pipe connector portion 216 is connected to the residual fuel outlet 218b located at the right front corner of the cylinder head 2 via the injector residual fuel return pipe 218c, which extends in the vertical direction (see reference). Figure 7 The connection 219a of the return pipe connector 216 is connected to the fuel tank 201 (see reference 201) via the upstream fuel return pipe 219b, the return pipe connection 220 provided above the fuel filter 202, and the downstream fuel return pipe 219c. Figure 6 In addition, at the upper part of the fuel filter 202, there is a fuel supply pipe 210 connected to the fuel tank 201 and a low-pressure fuel supply pipe 203 connected to the lower right side of the fuel supply pump 15.

[0074] In the engine 1 of this embodiment, a fuel supply pump 15, a common rail 16, and a fuel filter 202 are arranged at one corner of the engine 1 (here, the right front corner). Furthermore, a fuel return pipe connection 216 for residual fuel return, located at one end (front end) of the common rail 16, is connected to a pump residual fuel return pipe 217, an injector residual fuel return pipe 218c, and an upstream fuel return pipe 219b. By concentrating the fuel return pipes 217, 218c, and 219b at one corner of the engine 1, the length of these pipes can be shortened, thus simplifying the process. Furthermore, by concentrating the fuel supply pump 15, the common rail 16, and the fuel filter 202 at one corner of the engine 1, the length of the piping used to connect them (fuel supply low-pressure pipe 203, fuel supply high-pressure pipe 204, and common rail residual fuel return pipe 214) can be shortened, further simplifying the process.

[0075] like Figure 10As shown, engine 1 is an engine device equipped with a common rail 16 that stores fuel supplied from fuel supply pump 15 in a high-pressure manner. The common rail 16 has a pressure reducing valve 211 for discharging fuel in the common rail 16 to a fuel return pipe 214. The fuel return pipe 214 is guided from a position higher than the pressure reducing valve 211 and then guided to a position lower than the pressure reducing valve 211. Therefore, regardless of the mounting angle of the common rail 16 and the connection direction of the fuel return pipe 214, fuel can be stored between the fuel return pipe 214 portion at a position higher than the pressure reducing valve 211 and the pressure reducing valve 211, ensuring that the pressure reducing valve 211 is immersed in fuel and preventing abnormal wear of the sliding part of the pressure reducing valve 211. As a result, the mounting conditions of the common rail 16 are relaxed, thereby increasing the design freedom of engine 1.

[0076] Furthermore, in the above embodiment, although the connecting portion (fuel return pipe connecting portion 212, fuel return pipe connecting component 213) of the fuel return pipe 214 in the common rail 16 protrudes approximately horizontally from the outer peripheral surface of the common rail 16, the protruding direction of the connecting portion is not limited to this. For example, as Figure 14 As shown, the connecting portion 212 and the connecting member 213 can also be arranged to protrude from the outer peripheral surface of the common rail 16 in a downward-southward direction. In this embodiment, the fuel return pipe 214 extends from the common rail 16 in a downward-southward direction. In this embodiment, the fuel return pipe 214 is also guided from a position higher than the pressure reducing valve 211 to a position lower than the pressure reducing valve 211. Thus, fuel can be stored between the fuel return pipe 214 portion, which is higher than the pressure reducing valve 211, and the pressure reducing valve 211, ensuring that the pressure reducing valve 211 is immersed in fuel. Furthermore, as another variation, the fuel return pipe 214 can also be extended from the common rail 16 in a downward-southward direction, guided to a position higher than the pressure reducing valve 211, and then guided to a position lower than the pressure reducing valve 211.

[0077] In addition, such as Figures 1-10 As shown, engine 1 has the following structure: a common rail 16 is disposed below the intake manifold 3 located on cylinder head 2, and an EGR device 24 is connected to the intake manifold 3. The EGR device 24 is used to mix a portion of the exhaust gas discharged from exhaust manifold 4 into fresh gas. Since the middle section of fuel return pipe 214 is installed on EGR device 24 at a position higher than pressure relief valve 211, there is no need to provide a dedicated component in engine 1 to support the middle section of fuel return pipe 214, thereby reducing the manufacturing cost of engine 1. In addition, by arranging the common rail 16 below the high-rigidity intake manifold 3, the common rail 16 can be compactly arranged, and foreign objects can be prevented from contacting the common rail 16 from above, thereby physically protecting the common rail 16.

[0078] In addition, such as Figures 1-10 As shown, the fuel injection pipe 207, which extends from the common rail 16 towards the cylinder head 2, passes between the cylinder head 2 and the EGR device 24, thus protecting the fuel injection pipe 207 via the EGR device 24. Therefore, during engine 1 handling, the fuel injection pipe 207 is prevented from contacting other components or deforming due to falling foreign objects, and adverse conditions such as fuel leakage caused by damage to the fuel injection pipe 207 are eliminated.

[0079] Furthermore, the configuration of each part in this invention is not limited to the illustrated embodiment, and various modifications can be made without departing from the spirit of this invention.

[0080] Explanation of reference numerals in the attached figures

[0081] 1… Engine (engine unit); 2… Cylinder head; 3… Intake manifold; 4… Exhaust manifold; 15… Fuel supply pump; 16… Common rail; 24… EGR device (exhaust gas recirculation device); 207… Fuel injection pipe; 211… Pressure reducing valve; 214… Common rail residual fuel return pipe (fuel return pipe).

Claims

1. An engine assembly, wherein, The engine assembly includes: Common rail; and A fuel return pipe, which is connected to the common rail and allows fuel in the injector to return to the common rail. The fuel return pipe is connected to one end of the common rail.

2. The engine device according to claim 1, wherein, The fuel return pipe is located above the common rail.

3. The engine device according to claim 1 or 2, wherein, A portion of the common rail is configured to overlap with the intake manifold when viewed from above.

4. The engine device according to claim 1, wherein, The fuel return pipe is connected in the vertical direction.

5. The engine device according to claim 1, wherein, The engine unit has multiple fuel return pipes connected to one end of the common rail.

6. The engine device according to claim 1, wherein, The fuel return pipe also includes a second fuel return pipe that allows fuel from the fuel supply pump to return to the common rail.

7. The engine device according to claim 1, wherein, One end of the common rail is closer to the flywheel housing than the other end of the common rail.

8. The engine device according to claim 1, wherein, The engine unit also includes a third fuel return pipe, which is connected to one end of the common rail and allows fuel in the common rail to return to the fuel tank.

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