Patent Grant
11339747
This application is a national stage application pursuant to 35 U.S.C. § 371 of International Application No. PCT/JP2017/046518, filed on Dec. 26, 2017 which claims priority under 35 U.S.C. § 119 to Japanese Patent Application No. 2017-060187 filed on Mar. 24, 2017, the disclosures of which are hereby incorporated by reference in their entireties.
The present invention relates to an engine device including an exhaust pressure sensor configured to detect an exhaust gas pressure in an exhaust manifold.
Traditionally, an engine device having an exhaust pressure sensor configured to detect an exhaust gas pressure in an exhaust gas path is known (e.g. see Patent Literatures 1 and 2; hereinafter, referred to as PTL 1, PTL 2, respectively). Since the exhaust pressure sensor is vulnerable to heat, the exhaust gas path and the exhaust pressure sensor are connected through a pipe for detecting the exhaust pressure, so that a quantity of heat exceeding an allowable range is not transferred from the exhaust gas and components constituting the exhaust gas path to the exhaust pressure sensor.
PTL 1: Japanese Patent Application Laid-Open No. 2015-117585
PTL 2: Japanese Patent Application Laid-Open No. 2015-183549
In traditional art, the length of the pipe for detecting the exhaust pressure is sufficiently maintained so that the temperature of the exhaust pressure sensor does not exceed the allowable range. However, to achieve a sufficient length for the exhaust pressure sensor pipe within a limited space, it is necessary to bend the pipe in a complexed shape, and the layout becomes difficult. Further, manufacturability and assemblability are deteriorated, and the reliability is lowered. Therefore, there has been a space for improvement.
A technical problem of the present invention is to provide an engine device that is improved based on studies on the existing circumstances as mentioned above.
An engine device according to an aspect of the present invention is an engine device including: an exhaust manifold provided on an exhaust side surface of a cylinder head; and an exhaust pressure sensor configured to detect an exhaust gas pressure in the exhaust manifold, wherein: the exhaust pressure sensor is attached to the cylinder head; the exhaust manifold and the exhaust pressure sensor are connected to each other through an exhaust pressure bypass path provided in the cylinder head and an exhaust pressure detection pipe connecting the exhaust pressure bypass path to the exhaust manifold; and a cooling water passage is provided nearby the exhaust pressure bypass path, in the cylinder head.
The engine device according to the above aspect of the present invention may include, for example, an EGR (exhaust gas recirculation) device configured to return a part of exhaust gas discharged from the exhaust manifold to an air-intake manifold as an EGR gas; and the EGR cooler configured to cool the EGR gas, wherein: the cylinder head may have a pair of EGR cooler coupling portions which protrude from a first side surface out of two side surfaces of the cylinder head intersecting the exhaust side surface; the cooling water passage may be connected to the EGR cooler through one of the EGR cooler coupling portions; and the exhaust pressure bypass path may pass through the one of the EGR cooler coupling portions.
Further, the exhaust pressure sensor may be attached to an exhaust pressure sensor attaching part which protrudes from the first side surface of the cylinder head between the pair of EGR cooler coupling portions.
An engine device according to an aspect of the present invention is an engine device including: an exhaust manifold provided on an exhaust side surface of a cylinder head; and an exhaust pressure sensor configured to detect an exhaust gas pressure in the exhaust manifold. The exhaust pressure sensor is attached to the cylinder head. The exhaust pressure sensor is connected to the exhaust manifold through an exhaust pressure bypass path provided in the cylinder head and an exhaust pressure detection pipe connecting the exhaust pressure bypass path to the exhaust manifold. Therefore, heat of the exhaust pressure detection pipe can be radiated in the cylinder head. Thus, in the engine device according to the above aspect of the present invention, the length of the exhaust pressure detection pipe can be shortened while avoiding failure or malfunction of the exhaust pressure sensor which may otherwise be caused by heat of the exhaust manifold and the exhaust pressure detection pipe. Further, by shortening the length of the exhaust pressure detection pipe, the reliability of the exhaust pressure detection pipe is improved, and the exhaust pressure detection pipe is easily arranged. Therefore, the number of steps for designing can be reduced and the manufacturability and assemblability of the engine device can be improved. Further, in the cylinder head of the engine device according to the above aspect of the present invention, the cooling water passage is provided nearby the exhaust pressure bypass path. Therefore, the gas temperature in the exhaust pressure bypass path can be efficiently reduced. Thus, in the engine device according to the above aspect of the present invention, the exhaust pressure bypass path can be shortened while the heat transmitted from the gas in the exhaust pressure bypass path to the exhaust pressure sensor is kept within an acceptable range, and the exhaust pressure bypass path to the cylinder head can be easily formed, while avoiding failure or malfunction of the exhaust pressure sensor which may otherwise be caused by heat.
The engine device of the above aspect of the present invention may include, for example, an EGR device configured to return a part of exhaust gas discharged from the exhaust manifold to an air-intake manifold as an EGR gas; and the EGR cooler configured to cool the EGR gas, wherein: the cylinder head may have a pair of EGR cooler coupling portions which protrude from a first side surface out of two side surfaces of the cylinder head intersecting the exhaust side surface; the cooling water passage may be connected to the EGR cooler through one of the EGR cooler coupling portions; and the exhaust pressure bypass path may pass through the one of the EGR cooler coupling portions. This structure can efficiently cool the gas in the exhaust pressure bypass path, and can suppress or reduce failure or malfunction of the exhaust pressure sensor attributed to the heat.
Further, the exhaust pressure sensor may be attached to an exhaust pressure sensor attaching part which protrudes from the first side surface of the cylinder head between the pair of EGR cooler coupling portions. Therefore, the exhaust pressure sensor can be efficiently cooled, and failure or malfunction of the exhaust pressure sensor attributed to the heat can be suppressed or reduced.
In the following, an embodiment of the present invention will be described with reference to the drawings. First, referring to
As shown in
The crankshaft 5 has its front and rear distal ends protruding from front and rear surfaces of the cylinder block 6. The flywheel housing 7 is fixed to one side portion of the engine 1 (in the embodiment, a front side surface side of the cylinder block 6) intersecting the crankshaft 5. In the flywheel housing 7, a flywheel 8 is disposed. The flywheel 8, which is fixed to the front end side of the crankshaft 5, is configured to rotate integrally with the crankshaft 5. Through the flywheel 8, power of the engine 1 is extracted to an actuating part of a work machine (for example, a hydraulic shovel, a forklift, or the like). The cooling fan 9 is disposed in the other side portion of the engine 1 (in the embodiment, a rear surface side of the cylinder block 6) intersecting the crankshaft 5. A rotational force is transmitted from the rear end side of the crankshaft 5 to the cooling fan 9 through a belt 10.
An oil pan 11 is disposed on a lower surface of the cylinder block 6. A lubricant is stored in the oil pan 11. The lubricant in the oil pan 11 is suctioned by a lubricating oil pump (not shown) disposed on the side of the right side surface of the cylinder block 6, the lubricating oil pump being arranged in a coupling portion where the cylinder block 6 is coupled to the flywheel housing 7. The lubricant is then supplied to lubrication parts of the engine 1 through an oil cooler 13 and an oil filter 14 that are disposed on the right side surface of the cylinder block 6. The lubricant supplied to the lubrication parts is then returned to the oil pan 11. The lubricant pump is configured to be driven by rotation of the crankshaft 5.
As shown in
Each of the injectors is connected to a fuel tank (not shown) through the fuel feed pump 15 and the common rail 16 having a cylindrical shape. The fuel tank is mounted in a work vehicle. A fuel in the fuel tank is pressure-fed from the fuel feed pump 15 to the common rail 16, so that a high-pressure fuel is stored in the common rail 16. By controlling the opening/closing of the fuel injection valves of the injectors, the high-pressure fuel in the common rail 16 is injected from the injectors to the respective cylinders of the engine 1.
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In the embodiment, the collector 25 of the EGR device 24 is coupled to the right side surface of the air-intake manifold 3 which is formed integrally with the cylinder head 2 to form the right side surface of the cylinder head 2. That is, an outlet opening of the collector 25 is coupled to an inlet opening of the air-intake manifold 3 provided on the right side surface of the cylinder head 2. An EGR gas inlet of the recirculation exhaust gas pipe 28 is coupled to an EGR gas outlet of the EGR gas passage provided in the cylinder head 2, in a position close to the front of the right side surface of the cylinder head 2. The EGR device 24 is fixed to the cylinder head 2, by attaching the collector 25 to the air-intake manifold 3, and attaching the recirculation exhaust gas pipe 28 to the cylinder head 2.
In the EGR device 24, the air-intake manifold 3 and the air-intake throttle member 26 for taking fresh air in are connected in communication with each other through the collector 25. With the collector 25, the EGR valve member 29 which leads to an outlet side of the recirculation exhaust gas pipe 28 is connected and communicated. The collector 25 is formed in a substantially cylindrical shape which is long in a front-rear direction. On a supplied-air inlet side (the front portion relative to the longitudinal direction) of the collector 25, the air-intake throttle member 26 is fastened by a bolt. A supplied-air exhaust side of the collector 25 is fastened, by a bolt, to the inlet side of the air-intake manifold 3. The EGR valve member 29 adjusts the opening degree of the EGR valve therein so as to adjust the supply amount of EGR gas to the collector 25.
In the collector 25, fresh air is supplied. Further, an EGR gas (a part of exhaust gas from the exhaust manifold 4) is supplied from the exhaust manifold 4 to the collector 25 through the EGR valve member 29. After the fresh air and the EGR gas from the exhaust manifold 4 are mixed in the collector 25, mixed gas in the collector 25 is supplied to the air-intake manifold 3. In this manner, the part of the exhaust gas discharged from the engine 1 to the exhaust manifold 4 is returned to the engine 1 from the air-intake manifold 3. Thus, the maximum combustion temperature at the time of high-load operation is reduced, and the amount of nitrogen oxide (NOx) from the engine 1 is reduced.
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In the exhaust path of the two-stage turbocharger 30, the high-pressure turbine case 53 is connected to the exhaust manifold 4. To the high-pressure turbine case 53, the low-pressure turbine case 55 is connected through a high-pressure exhaust gas pipe 59. To the low-pressure turbine case 55, an exhaust communication pipe 119 is connected. The high-pressure exhaust gas pipe 59 is formed of a flexible pipe. In this embodiment, a part of the high-pressure exhaust gas pipe 59 is formed in a bellows shape.
To the exhaust communication pipe 119, a tail pipe (not shown) is connected through an exhaust gas purification device 100. The exhaust gas discharged from each cylinder of the engine 1 to the exhaust manifold 4 is emitted from the tail pipe to the outside through the two-stage turbocharger 30, the exhaust gas purification device 100, and the like.
In an air-intake path of the two-stage turbocharger 30, the low-pressure compressor case 56 is connected to the air cleaner through an air supply pipe 62, the high-pressure compressor case 54 is coupled with the low-pressure compressor case 56 through a low-pressure fresh air passage pipe 65, and the air-intake throttle member 26 of the EGR device 24 is connected to the high-pressure compressor case 54 through an intercooler (not shown). The fresh air (outside air) suctioned by the air cleaner is subjected to dust removal and purification in the air cleaner, and fed to the air-intake manifold 3 through the two-stage turbocharger 30, the intercooler, the air-intake throttle member 26, the collector 25, and the like, and then supplied to the respective cylinders of the engine 1.
The exhaust gas purification device 100 is for collecting particulate matter (PM) and the like in the exhaust gas. As shown in
On both left and right sides (one end side relative to the longitudinal direction and the other end side relative to the longitudinal direction) of the exhaust gas purification device 100, an exhaust gas intake side and an exhaust gas discharge side are provided in a manner distributed to the left and right. The exhaust gas inlet pipe 116 on the exhaust gas intake side of the exhaust gas purification device 100 is connected to the exhaust gas outlet of the low-pressure turbine case 55 of the two-stage turbocharger 30, through an exhaust connecting member 120 having an exhaust gas passage having a substantially L-shape in a side view, and a linear exhaust communication pipe 119. The exhaust connecting member 120 is fixed to a left side surface of the support pedestal 121. The exhaust gas discharge side of the exhaust gas purification device 100 is connected to an exhaust gas intake side of the tail pipe (not shown).
The exhaust gas purification device 100 has a structure in which a diesel oxidation catalyst 102 made of platinum and the like for example and a soot filter 103 having a honeycomb structure are serially aligned and accommodated. In the above structure, nitrogen dioxide (NO2) generated by an oxidation action of the diesel oxidation catalyst 102 is taken into the soot filter 103. The particulate matter contained in the exhaust gas from the engine 1 is collected by the soot filter 103, and is continuously oxidized and removed by the nitrogen dioxide. Therefore, in addition to removal of the particulate matter (PM) in the exhaust gas from the engine 1, content of carbon monoxide (CO) and hydrocarbon (HC) in the exhaust gas from the engine 1 is reduced.
The exhaust gas purification device 100 includes: an upstream case 105 having, on its outer circumferential surface, the exhaust gas inlet pipe 116; an intermediate case 106 coupled to the upstream case 105; and a downstream case 107 coupled to the intermediate case 106. The upstream case 105 and the intermediate case 106 are serially aligned and coupled to form a gas purification housing 104 made of a refractory metal material. In the gas purification housing 104, the diesel oxidation catalyst 102 and the soot filter 103 are accommodated over a cylindrical inner case (not shown). Further, the downstream case 107 has therein an inner case (not shown) having a large number of muffling holes, and a muffling material made of ceramic fibers is filled between the inner case and the downstream case 107 to form a muffler.
When the exhaust gas passes the diesel oxidation catalyst 102 and the soot filter 103, the nitrogen monoxide in the exhaust gas is oxidized to unstable nitrogen dioxide by the action of the diesel oxidation catalyst 102, provided that the exhaust gas temperature exceeds a renewable temperature (e.g., about 300° C.). Oxygen is released at the time of the nitrogen dioxide returning to nitrogen monoxide. With this oxygen, the particulate matter deposited on the soot filter 103 is oxidized and removed. This restores a particulate matter collection performance of the soot filter 103, thereby renewing the soot filter 103.
Next, with reference to
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On the other hand, the low-pressure turbocharger 52 includes: the low-pressure turbine case 55; the low-pressure compressor case 56 arranged at the rear of the low-pressure turbine case 55; and a low-pressure center housing 75 joining both cases 55, 56. The low-pressure turbine case 55 includes: a low-pressure exhaust gas inlet 60 in communication with the downstream end portion of the high-pressure exhaust gas pipe 59; and a low-pressure exhaust gas outlet 61 in communication with the upstream end portion of the exhaust communication pipe 119. The low-pressure compressor case 56 includes: a low-pressure fresh air inlet 63 in communication with the downstream end portion of the air supply pipe 62; and a low-pressure fresh air supply port 64 in communication with the upstream end portion of the low-pressure fresh air passage pipe 65.
The exhaust manifold exhaust gas outlet 49 of the exhaust manifold 4, which discharges an exhaust gas, is opened toward the left lateral side. The high-pressure exhaust gas inlet 57 of the high-pressure turbine case 53 is opened toward the exhaust manifold 4, and the high-pressure exhaust gas outlet 58 of the high-pressure turbine case 53 is opened frontward. Further, the low-pressure exhaust gas inlet 60 of the low-pressure turbine case 55 is opened downward, and the low-pressure exhaust gas outlet 61 of the low-pressure turbine case 55 is opened frontward.
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The turbocharger-side plane portion 132a of the attachment bracket 132 is fixed to a right edge portion of the front side surface of the low-pressure compressor case 56 by a bolt 133. To the low-pressure turbocharger attaching part 131, the head-side plane portion 132b of the attachment bracket 132 is fixed by a pair of front and rear bolts 134. This way, the low-pressure turbocharger 52 is fixed to the robust cylinder head 2.
In this embodiment, since the low-pressure turbocharger 52 is fixed to the left side surface (the exhaust side surface) of the cylinder head 2 and the high-pressure turbocharger 51 is fixed to the exhaust manifold 4, the high-pressure turbocharger 51 and the low-pressure turbocharger 52 constituting the two-stage turbocharger 30 can be distributed to and firmly fixed to the robust cylinder head 2 and the exhaust manifold 4. Further, since the low-pressure turbocharger 52 is coupled to the support pedestal 121 fixed to the front portion of the cylinder head 2 through the exhaust communication pipe 119 and the exhaust connecting member 120, the low-pressure turbocharger 52 can be reliably fixed to the engine 1, and the two-stage turbocharger 30 can be therefore reliably fixed to the engine 1.
Further, since the high-pressure exhaust gas outlet 58 of the high-pressure turbocharger 51 and the low-pressure exhaust gas inlet 60 of the low-pressure turbocharger 52 are coupled through a flexible high-pressure exhaust gas pipe 59, the risk of low cycle fatigue breakdown of the high-pressure exhaust gas pipe 59 due to thermal expansion can be reduced. Further, a stress to the two-stage turbocharger 30, attributed to thermal expansion of the high-pressure exhaust gas pipe 59, can be reduced. As a result, a stress applied to a coupling portion of the high-pressure turbocharger 51 and the exhaust manifold 4, and a stress applied to a coupling portion of the low-pressure turbocharger 52 and the cylinder head 2 can be reduced, and coupling failure at these coupling portions and damages to coupling members can be suppressed or reduced.
As shown in
In this embodiment, the engine 1 is an OHV type, and the space surrounded by the cylinder head 2 and the cylinder head cover 18 serves as a rocker arm chamber. As shown in
As shown in
In the present invention, effects similar to those of the present embodiment can be achieved, irrespective of the position and direction in which the exhaust gas purification device 100 is mounted, provided that the exhaust gas inlet of the exhaust gas purification device 100 is arranged nearby a corner portion where the front side surface (first side surface) and the left side surface (exhaust side surface) of the cylinder head 2 intersect. For example, the exhaust gas purification device 100 may be arranged in front of the cylinder head 2 and above the flywheel housing 7, in such a manner as to take a posture that is long in the left-right direction (e.g., see Japanese Patent Application Laid-Open No. 2011-012598), or arranged above the cylinder head 2, in such a manner as to take a posture that is long in the front-rear direction (in a direction along the crankshaft 5) (e.g., see Japanese Patent Application Laid-Open No. 2016-079870).
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The low-pressure fresh air passage pipe 65 includes a metal pipe 65a and a resin pipe 65b. The metal pipe 65a has a substantially U-shape and has its one end flange-coupled and bolt-fastened to the high-pressure fresh air inlet 66. The resin pipe 65b allows the other end of the metal pipe 65a to communicate with the low-pressure fresh air supply port 64 of the low-pressure compressor case 56. This way, in the low-pressure fresh air passage pipe 65, the metal pipe 65a can be fixed to the high-pressure compressor case 54 with a high rigidity, and the resin pipe 65b can communicate the low-pressure compressor case 56 with the metal pipe 65a while lessening an assembling error therebetween.
Further, the low-pressure fresh air supply port 64 of the low-pressure compressor case 56 extends obliquely upper left from a lower left portion of the outer circumferential surface of the low-pressure compressor case 56, and is bent rearward. Therefore, the low-pressure fresh air passage pipe 65 (metal pipe 65a) can be bent with a large curvature. Therefore, generation of a turbulent flow in the low-pressure fresh air passage pipe 65 can be suppressed, so that the compressed air discharged from the low-pressure compressor case 56 can be smoothly supplied to the high-pressure compressor case 54.
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The high-pressure lubricant supply pipe 73 has its lower end connected to a connection member 78a disposed in a middle portion on the left side surface of the cylinder block 6, and its upper end coupled to the upper portion of the high-pressure center housing 72 of the high-pressure turbocharger 51. A coupling joint 78b is provided in the upper portion of the high-pressure center housing 72, the coupling joint 78b allowing the upper end of the high-pressure lubricant supply pipe 73 to communicate with a lower end of the low-pressure lubricant supply pipe 76. An upper end of the low-pressure lubricant supply pipe 76 is coupled to a connecting member 78c provided at an upper portion of the low-pressure center housing 75 of the low-pressure turbocharger 52. This way, the lubricant flowing in the oil passage in the cylinder block 6 is supplied to the high-pressure center housing 72 of the high-pressure turbocharger 51 through the high-pressure lubricant supply pipe 73, and is supplied to the low-pressure center housing 75 of the low-pressure turbocharger 52 through the high-pressure lubricant supply pipe 73 and the low-pressure lubricant supply pipe 76.
The high-pressure lubricant supply pipe 73 extends obliquely upper rearward from the connection member 78a on the left side surface of the cylinder block 6, and passes between the high-pressure compressor case 54 and the cylinder block 6, to a position facing the left side surface of the cylinder head 2. Further, the high-pressure lubricant supply pipe 73 bypasses the rear end portion of the exhaust manifold 4, passes the right lateral side of the high-pressure center housing 72, and leads to the coupling joint 78b. Further, the low-pressure lubricant supply pipe 76 has a substantially L-shape in a side view, and extends from the coupling joint 78b to the connecting member 78c along the high-pressure turbocharger 51 and the high-pressure exhaust gas pipe 59. Such a piping layout surrounding the two-stage turbocharger 30 which is a high-rigidity component with the lubricant supply pipes 73, 76 shortened enables the lubricant to be efficiently supplied to the two-stage turbocharger 30 and simultaneously prevents the lubricant supply pipes 73, 76 from being damaged by an external force.
Further, the high-pressure lubricant return pipe 74 has one end (lower end) connected to a leading end surface of a coupling joint 80 provided in a middle portion of the left side surface of the cylinder block 6, above the connection member 78a. The other end (upper end) of the high-pressure lubricant return pipe 74 is coupled to a lower portion of the outer circumferential surface of the high-pressure center housing 72 of the high-pressure turbocharger 51. Further, the low-pressure lubricant return pipe 77 has one end (lower end) connected to a connecting part that protrudes in an obliquely upper forward direction from a midway portion of the coupling joint 80. The other end (upper end) of the low-pressure lubricant return pipe 77 is coupled to a lower portion of the outer circumferential surface of the low-pressure center housing 75 of the low-pressure turbocharger 52. Therefore, the lubricant flowing in the high-pressure turbocharger 51 and the low-pressure turbocharger 52 flows from the lower portion of the center housings 72, 75 through the lubricant return pipes 74, 77, merged in the coupling joint 80, and returned to the oil passage in the cylinder block 6.
The high-pressure lubricant return pipe 74 extends from below the high-pressure turbine case 53, passes below the exhaust manifold exhaust gas outlet 49 of the exhaust manifold 4, and leads to the coupling joint 80. Further, the low-pressure lubricant return pipe 77 passes between the high-pressure exhaust gas pipe 59 and the exhaust manifold 4, and leads to the coupling joint 80. Such a piping layout surrounding the two-stage turbocharger 30 which is a high-rigidity component with the lubricant return pipes 74, 77 shortened enables the lubricant to be efficiently supplied to the two-stage turbocharger 30 and simultaneously prevents the lubricant return pipes 74, 77 from being damaged by an external force.
Next, the following describes a structure of attaching the exhaust gas purification device 100 with reference to
The coupling portion of the upstream case 105 and the intermediate case 106 are connected by a pair of thick plate-like sandwiching flanges 108, 109 from both sides relative to the direction in which the exhaust gas moves. That is, a coupling flange at a downstream side opening edge of the upstream case 105 and a coupling flange at an upstream side opening edge of the intermediate case 106 are sandwiched by the sandwiching flanges 108, 109 to join together the downstream side of the upstream case 105 with the upstream side of the intermediate case 106, thereby structuring the gas purification housing 104. At this time, by bolt-fastening the sandwiching flanges 108, 109, the upstream case 105 and the intermediate case 106 are detachably coupled.
The coupling portion of the intermediate case 106 and the downstream case 107 are connected by a pair of thick plate-like sandwiching flanges 110, 111 from both sides relative to the direction in which the exhaust gas moves. That is, a coupling flange at a downstream side opening edge of the intermediate case 106 and a coupling flange at an upstream side opening edge of the downstream case 107 are sandwiched by the sandwiching flanges 110, 111 to join together the downstream side of the intermediate case 106 with the upstream side of the downstream case 107.
The exhaust gas inlet pipe 116 is provided at an outer peripheral portion on an exhaust gas inlet side of the upstream case 105. The exhaust gas intake side of the exhaust gas inlet pipe 116 communicates with the low-pressure exhaust gas outlet 61 (see
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The left and right support brackets 117, 118 each has a substantially L-shape with a horizontal portion and a rising portion protruding upward from the left or right outer side end of the horizontal portion. The horizontal portion of the left support bracket 117 is fixed by a pair of front and rear bolts to an upper surface portion of a flat portion 121a of the support pedestal 121 close to the left side. The horizontal portion of the right support bracket 118 is fixed by a pair of front and rear bolts to an upper surface right edge portion of the flat portion 121a of the support pedestal 121. The right and left bracket fastening legs 112, 113 of the exhaust gas purification device 100 are attached to the left and right support brackets 117, 118, each with a pair of front and rear bolts and nuts.
On the upper surface of the rising portion of the right support bracket 118, there is a cut-out portion 118a that enables temporarily placing a head portion of the bolt fastening the lower portions of the sandwiching flanges 110, 111. When the exhaust gas purification device 100 is to be assembled with the engine 1, the head portion of the bolt fastening the lower portion of the sandwiching flanges 110, 111 is positioned to the cut-out portion 118a of the right support bracket 118, while the left and right support brackets 117, 118 and the exhaust connecting member 120 are attached to the support pedestal 121. This way, the exhaust gas purification device 100 can be positioned with respect to the engine device 1, and fastening bolts at a time of assembling the exhaust gas purification device 100 with the engine 1 becomes easy. Therefore, the workability for assembling is improved.
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Further, the support pedestal 121 has a plurality of legs 121b, 121c, 121d, 121e which protrude downward from the flat portion 121a and are fixed to the cylinder head 2. Portions between the legs 121b, 121c, 121d, 121e are formed in an arch-shape which is convex upward. The cylinder head 2 includes: an exhaust side attaching part 123b provided in a front portion of the left side surface; a first center attaching part 123c provided in a middle portion of the front side surface, close to the top; a second center attaching part 123d provided in a right edge portion of the front side surface; and an air-intake side attaching part 123e provided in a front end portion of the upper surface of the air-intake manifold 3 which is integrally formed on the right side surface.
A lower end portion of the exhaust side leg 121b is fixed to the exhaust side attaching part 123b with a pair of front and rear bolts. A lower end portion of the first center leg 121c is fixed to the first center attaching part 123c with a single bolt. A lower portion of the second center leg 121d is fixed to the second center attaching part 123d with a pair of upper and lower bolts. The air-intake side leg 121e has a pair of front and rear bolt insertion holes bored in an up-down direction, and is attached to the air-intake side attaching part 123e by a pair of front and rear bolts inserted into the bolt insertion holes.
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The support pedestal 121 includes: the exhaust side leg 121b fixed to the left side surface of the cylinder head 2; the air-intake side leg 121e fixed to the right side surface of the cylinder head 2; and the center legs 121c, 121d fixed to the front side surface of the cylinder head 2. Therefore, the support pedestal 121 can be fixed to three surfaces of the cylinder head 2, i.e., the right side surface, the left side surface, and the front side surface. Therefore, the support rigidity of the exhaust gas purification device 100 can be improved.
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Next, the following describes a structure around the front side surface of the cylinder head 2 with reference to
On the right side surface of the exhaust manifold 4, which is coupled to the left side surface of the cylinder head 2, an EGR gas outlet 41 communicating with the upstream EGR gas passage 31 in the cylinder head 2 and an exhaust gas inlet 42 communicating with the plurality of exhaust gas passages 37 are arranged in the front-rear direction, and are opened. In the exhaust manifold 4, an exhaust aggregate part 43 communicating with the EGR gas outlet 41 and the exhaust gas inlet 42 is formed. In a rear portion of the left side surface of the exhaust manifold 4, an exhaust manifold exhaust gas outlet 49 communicating with the exhaust aggregate part 43 is opened. After the exhaust gas coming from the exhaust gas passage 37 of the cylinder head 2 flows into the exhaust aggregate part 43 through the exhaust gas inlets 42, part of the exhaust gas serves as an EGR gas and flows into the upstream EGR gas passage 31 of the cylinder head 2 through the EGR gas outlet 41 while the rest of the exhaust gas flows into the two-stage turbocharger 30 (see
In the cylinder head 2, the exhaust manifold 4 is coupled to the left side surface (exhaust side surface) which is opposite to the right side surface (air-intake side surface) where the air-intake manifold 3 is integrally formed, and the EGR cooler 27 is coupled to the front side surface (first side surface of out of two side surfaces intersecting the exhaust side surface). The left and right EGR cooler coupling portions 33, 34 are provided at the left and right edge portions of the front side surface of the cylinder head 2 (left and right front corner portions of the cylinder head 2) so as to protrude forward. The EGR cooler 27 is coupled to the front side surfaces of the left and right EGR cooler coupling portions 33, 34. In the EGR cooler coupling portions 33, 34, the EGR gas passages 31, 32 and the cooling water passages 38, 39 are formed.
Since the EGR gas passages 31, 32 and the cooling water passages 38, 39 are provided in the EGR cooler coupling portions 33, 34, there is no need for arranging that cooling water piping and EGR gas piping between the EGR cooler 27 and the cylinder head 2. This can give a sealability to a coupling portion coupled to the EGR cooler 27 without any influence of, for example, extension and contraction of piping caused by the EGR gas or the cooling water. This can also enhance a resistance (structural stability) against external fluctuation factors such as heat and vibration, and moreover can make the configuration compact.
As shown in
In the left EGR cooler coupling portion 33, a downstream cooling water passage 38 is formed to lead to the rear side from the front side surface of the left EGR cooler coupling portion 33. The downstream cooling water passage 38 is provided on the upper side of the upstream EGR gas passage 31 and feeds cooling water discharged from an upper left portion of the back surface of the EGR cooler 27 to the cooling water passage in the cylinder head 2. In the right EGR cooler coupling portion 34, an upstream cooling water passage 39 is formed to lead to the rear side from the front side surface of the right EGR cooler coupling portion 34. The upstream cooling water passage 39 is provided on the lower side of the downstream EGR gas passage 32 and feeds cooling water flowing in the cooling water passage in the cylinder head 2 to a lower right portion of the back surface of the EGR cooler 27.
As shown in
The exhaust pressure sensor 151 is connected to the exhaust manifold 4 through an exhaust pressure bypass path 153 provided in the cylinder head 2 and an exhaust pressure detection pipe 154 connecting the exhaust pressure bypass path 153 to the exhaust manifold 4. The exhaust pressure bypass path 153 is bored from the front end portion of the left side surface of the cylinder head 2 toward the right lateral side, and extended to the inside of the exhaust pressure sensor attaching part 152 through the inside of the left EGR cooler coupling portion 33. The exhaust pressure bypass path 153 is bent forward in the exhaust pressure sensor attaching part 152, and opened in the front side surface of the exhaust pressure sensor attaching part 152. To the front side surface of the exhaust pressure sensor attaching part 152, a hole closing member 155 for closing an end portion of the exhaust pressure bypass path 153 is attached.
As shown in
Meanwhile, the exhaust pressure detection pipe 154 is arranged above the exhaust manifold 4, on the left lateral side of the front portion of the left side surface of the cylinder head 2. A detection pipe attaching base 156 protrudes upward at a portion of the upper surface of the exhaust manifold 4, close to the front. A rear side joint member 157 is attached to an upper surface of the detection pipe attaching base 156. Further, a front side joint member 158 is attached to an end portion of the exhaust pressure bypass path 153 opened at the front end portion of the left side surface of the cylinder head 2. A front end of the exhaust pressure detection pipe 154 is connected to the exhaust pressure bypass path 153 through the front side joint member 158. A rear end of the exhaust pressure detection pipe 154 is connected to the exhaust aggregate part 43 (see
The heat transmitted from the exhaust manifold 4 with a high temperature to the exhaust pressure detection pipe 154 is spread by the cylinder head 2 through the front side joint member 158. This way, the heat from the exhaust manifold 4 and the heat from the exhaust pressure detection pipe 154 are not directly conducted to the exhaust pressure sensor 151 which is vulnerable to heat. Therefore, the length of the exhaust pressure detection pipe 154 can be shortened while avoiding failure or malfunction of the exhaust pressure sensor 151 caused by heat of the exhaust manifold 4 and the exhaust pressure detection pipe 154. Further, by shortening the length of the exhaust pressure detection pipe 154, the reliability of the exhaust pressure detection pipe 154 is improved, and the exhaust pressure detection pipe 154 is easily arranged. Therefore, the number of steps for designing can be reduced and the manufacturability and assemblability of the engine 1 can be improved.
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Further, as shown in
Since the EGR cooler coupling portions 33, 34 are configured in a protruding manner as shown in
Further, the left EGR cooler coupling portion 33 on the exhaust manifold 4 side and the right EGR cooler coupling portion 34 on the air-intake manifold 3 side are distant from each other. This can suppress a mutual influence between thermal deformations of the EGR cooler coupling portions 33, 34. Accordingly, gas leakage, cooling water leakage, and damages and the like of coupling portions where the EGR cooler coupling portions 33, 34 are coupled to the EGR cooler 27 can be suppressed or reduced, and in addition, a balance of the rigidity of the cylinder head 2 can be maintained. Further, since the volume at the front side surface of the cylinder head 2 can be reduced, weight reduction of the cylinder head 2 can be achieved. Further, since the EGR cooler 27 can be arranged at a distance from the front side surface of the cylinder head 2, creating a space on the front and rear sides of the EGR cooler 27, cool air can flow around the EGR cooler 27, and hence the cooling efficiency of the EGR cooler 27 can be increased.
As shown in
Since the EGR gas passages 31, 32 and the cooling water passages 38, 39 are provided in the EGR cooler coupling portions 33, 34 protruding at a distance from each other, a mutual influence between thermal deformations of the EGR cooler coupling portion 33, 34 is relieved. In the EGR cooler coupling portions 33, 34, the EGR gas flowing in the EGR gas passages 31, 32 is cooled by the cooling water flowing in the cooling water passages 38, 39, so that thermal deformations of the EGR cooler coupling portions 33, 34 are suppressed. In addition, the up-down positional relationship of the EGR gas passages 31, 32 and the cooling water passages 38, 39 in one of the EGR cooler coupling portions 33, 34 is reverse to that in the other of the EGR cooler coupling portions 33, 34. As a result, heat distributions in the respective EGR cooler coupling portions 33, 34 are in opposite directions with respect to the up-down direction, which can reduce an influence of thermal deformation in the height direction in the cylinder head 2.
Next, a part of a harness structure arranged around the front side surface of the cylinder head 2 is described with reference to
A front end portion of the harness assembly 171 is arranged between the cylinder head cover 18 and the air-intake side leg 121e of the support pedestal 121. The harness collection member 171 is branched into an EGR valve harness 172, an EGR gas temperature sensor harness 173, and a sensor harness assembly 174 nearby the right front corner portion of the cylinder head cover 18. The EGR valve harness 172 passes between the second center leg 121d and the air-intake side leg 121e of the support pedestal 121, and is electrically connected to the EGR valve member 29. The EGR gas temperature sensor harness 173 passes between the second center leg 121d and the air-intake side leg 121e, and is electrically connected to the EGR gas temperature sensor 181 configured to detect the exhaust gas temperature in the recirculation exhaust gas pipe 28.
The sensor harness assembly 174 extends toward the left lateral side from the harness assembly 171, and is bent downward at the front of a portion close to the right of the front side surface of the cylinder head cover 18. A front end portion of the sensor harness assembly 174 is branched into a rotation angle sensor harness assembly 175 and an exhaust pressure sensor harness 176. The exhaust pressure sensor harness 176 extends from the harness assembly 174 toward the left lateral side, passes between the cylinder head cover 18 and the first center leg 121c of the support pedestal 121, and is electrically connected to the exhaust pressure sensor 151.
The rotation angle sensor harness set member 175 extends downward along the front side surface of the cylinder head 2, from the sensor harness assembly 174. Further, the rotation angle sensor harness assembly 175 is bent to the left lateral side at a position immediately above the flywheel housing 7, so as to extend toward the front of the lower left corner portion of the front side surface of the cylinder head 2. The rotation angle sensor harness assembly 175 is branched into a crankshaft rotation angle sensor harness 177 and a camshaft rotation angle sensor harness 178. The crankshaft rotation angle sensor harness 177 is electrically connected to a crankshaft rotation angle sensor 182 (see
As shown in
As shown in
The EGR cooler 27 is attached to the pair of left and right EGR cooler coupling portions 33, 34 protruding forward from the front side surface of the cylinder head 2. Between the back surface of the EGR cooler 27 and the cylinder head 2, a space is formed. In this space, the rotation angle sensor harness assembly 175 is arranged in the up-down direction. This can protect the rotation angle sensor harness assembly 175, and make it easier to design a layout of the rotation angle sensor harness assembly 175.
Furthermore, a space is formed between a side surface of the cylinder head cover 18 and the support pedestal 121. In this space, the harness assembly 171, 174 and harnesses 172, 173, 176 are arranged. This can protect the harnesses and the harness assembly, and make it easy to design a layout of the harnesses becomes easy.
As shown in
In the engine 1, since the low-pressure turbocharger 52 is fixed to the exhaust side surface of the cylinder head 2 and the high-pressure turbocharger 51 is fixed to the exhaust manifold 4, the high-pressure turbocharger 51 and the low-pressure turbocharger 52 constituting the two-stage turbocharger 30 can be distributed to and firmly fixed to the robust cylinder head 2 and the exhaust manifold 4. Further, since the high-pressure exhaust gas outlet 58 of the high-pressure turbocharger 51 and the low-pressure exhaust gas inlet 60 of the low-pressure turbocharger 52 are coupled through a flexible high-pressure exhaust gas pipe 59, a stress to the two-stage turbocharger 30, attributed to thermal expansion of the high-pressure exhaust gas pipe 59, can be reduced. As a result, a stress applied to a coupling portion of the high-pressure turbocharger 51 and the exhaust manifold 4, and a stress applied to a coupling portion of the low-pressure turbocharger 52 and the cylinder head 2 can be reduced, and coupling failure at these coupling portions and damages to coupling members can be suppressed or reduced.
The cylinder head 2 has therein a rib 135 extended from a low-pressure turbocharger attaching part 131 on the exhaust side surface toward an air-intake side surface (e.g., right side surface) facing the exhaust side surface. With this structure, the rigidity of the cylinder head nearby the low-pressure turbocharger attaching part 131 can be improved in the cylinder head 2, and deformation and the like of the cylinder head 2 which is caused by attaching the low-pressure turbocharger 52 to the cylinder head 2 can be suppressed or reduced.
Further, the engine 1 includes an exhaust gas purification device 100 for purifying the exhaust gas from the engine 1. An exhaust gas inlet pipe 116 of the exhaust gas purification device 100 serving as an exhaust gas inlet is arranged nearby a corner where the exhaust side surface intersects with a first side surface out of two side surfaces of the cylinder head 2 intersecting the exhaust side surface, and the low-pressure turbocharger 52 is disposed close to the first side surface in such a manner that a low-pressure exhaust gas outlet 61 of the low-pressure turbocharger 52 faces the first side surface. Therefore, in the engine 1, the exhaust communication pipe 119 and the exhaust connecting member 120 as an example of piping connecting the low-pressure exhaust gas outlet 61 of the low-pressure turbocharger 52 and the exhaust gas inlet pipe 116 of the exhaust gas purification device 100 can be shortened and simplified. This way, the exhaust gas supplied to the exhaust gas purification device 100 can be kept at a high temperature, and a drop in the regeneration performance of the exhaust gas purification device 100 can be suppressed or reduced.
Further, above the cylinder head 2, a blow-by gas outlet 70 of the blow-by gas recirculation device 19 is arranged in a position close to a second side surface of the cylinder head 2 on the opposite side of the first side surface in such a manner as to face toward the exhaust side surface, and a low-pressure fresh air inlet 63 of the low-pressure turbocharger 52 is provided to face the second side surface. Further, the blow-by gas outlet 70 is coupled with an air supply pipe 62 coupled to the low-pressure fresh air inlet 63 of the low-pressure turbocharger 52 through a recirculation hose 68. Thus, in the engine 1, the recirculation hose 68 can be shortened and measures against freezing inside the recirculation hose 68 are no longer necessary, by arranging both the blow-by gas outlet 70 of the blow-by gas recirculation device 19 and the air supply pipe 62 coupled to the low-pressure fresh air inlet 63 of the low-pressure turbocharger 52 at a position close to the second side surface of the cylinder head 2.
As shown in
In the engine 1, the exhaust manifold 4 and the air-intake manifold 3 are arranged in a distributed manner to the exhaust side surface and the air-intake side surface of the cylinder head 2. The support pedestal 121 is arranged above the first side surface out of the two side surfaces of the cylinder head 2 intersecting an axial direction of the crankshaft 5, and includes as the legs: the exhaust side leg 121b fixed to the exhaust side surface; the air-intake side leg 121e fixed to the air-intake side surface; and the center legs 121c, 121d fixed to the first side surface. Therefore, in the engine 1, the support pedestal 121 can be fixed to three surfaces of the cylinder head 2, i.e., the exhaust side surface, the air-intake side surface, and the first side surface. Therefore, the support rigidity of the exhaust gas purification device 100 can be improved. Further, by making the height and size of the arch-shape between the exhaust side leg 121b and the first center leg 121c different from the height and size of the arch-shape between the air-intake side leg 121e and the second center leg 121d, or making the lengths of the exhaust side leg 121b and the air-intake side leg 121e different from each other, vibration on the air-intake side and the exhaust gas side can be cancelled by the support pedestal 121, and vibration of the exhaust gas purification device 100 can be reduced.
Further, the engine 1 includes a cooling fan 9 on the second side surface out of the two side surface of the cylinder head 2. Between the cylinder head cover 18 on the cylinder head 2 and the support pedestal 121, there is a cooling air passage 148 in which cooling air 149 from the cooling fan 9 flows. Therefore, in the engine 1, the cooling air from the cooling fan 9 can be guided to the first side surface of the cylinder head 2 through the cooling air passage 148, and the surroundings of the first side surface of the cylinder head 2 can be suitably cooled.
Further, the engine 1 includes: an EGR device 24 configured to return a part of exhaust gas discharged from the exhaust manifold 4 to the air-intake manifold 3 as an EGR gas; an EGR cooler 27 configured to cool the EGR gas; and an exhaust pressure sensor 151 configured to detect an exhaust gas pressure in the exhaust manifold 4. The EGR cooler 27 and the exhaust pressure sensor 151 are attached to the first side surface of the cylinder head 2. Therefore, the cooling air 149 from the cooling fan 9 guided to the first side surface through the cooling air passage 148 can facilitate cooling of the EGR cooler 27 and achieve suppression and reduction of thermal damages to the exhaust pressure sensor 151.
Further, in the engine 1, the air-intake manifold 3 is integrally formed with the air-intake side surface of the cylinder head 2, and the air-intake side leg 121e is fixed to the upper surface of the air-intake manifold 3. Therefore, the air-intake side leg 121e can be placed on and fixed firmly on top of the robust air-intake manifold 3. Further, the work of tightening or loosening the pair of bolts for fixing the air-intake side leg 121e to the air-intake manifold 3 can be performed from the upper side of the cylinder head 2. Therefore, work for attaching and removing the support pedestal 121 can be performed while the EGR device 24 arranged on a lateral side of the air-intake side surface of the cylinder head 2 is attached to the air-intake manifold 3. Therefore, the workability for assembling and maintenance of the engine 1 can be improved.
As shown in
Further, the engine 1 includes: the EGR device 24 configured to return a part of exhaust gas discharged from the exhaust manifold 4 to the air-intake manifold 3 as an EGR gas; the EGR cooler 27 configured to cool the EGR gas. The cylinder head 2 has the pair of EGR cooler coupling portions 33, 34 which protrude from the first side surface out of two side surfaces of the cylinder head 2 intersecting the exhaust side surface. The cooling water passage 38 is connected to the EGR cooler 37 through one EGR cooler coupling portion 33, and the exhaust pressure bypass path 153 passes through the EGR cooler coupling portion 33. Therefore, the engine 1 can efficiently cool the gas in the exhaust pressure bypass path 153, and can suppress or reduce failure or malfunction of the exhaust pressure sensor 151 attributed to the heat.
Further, the exhaust pressure sensor 151 is attached to the exhaust pressure sensor attaching part 152 which protrudes from the first side surface of the cylinder head 2 between the pair of EGR cooler coupling portions 33, 34. Therefore, the engine 1 can efficiently cool the exhaust pressure sensor 151, and can suppress or reduce failure or malfunction of the exhaust pressure sensor 151 attributed to the heat.
The configurations of respective parts of the present invention are not limited to those of the illustrated embodiment, but can be variously changed without departing from the gist of the invention.
| Number | Date | Country | Kind |
|---|---|---|---|
| JP2017-060187 | Mar 2017 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2017/046518 | 12/26/2017 | WO | 00 |
| Publishing Document | Publishing Date | Country | Kind |
|---|---|---|---|
| WO2018/173406 | 9/27/2018 | WO | A |
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