JP2006328954A - Exhaust system of engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a load applied to an exhaust manifold, and to improve cooling performance of a turbocharger. <P>SOLUTION: This invention is an exhaust system of an engine for arranging a catalytic converter in an exhaust pipe connected to an exhaust outlet flange of this turbocharger and extending to the rear of a vehicle, by installing the turbocharger on an exhaust pipe installing surface via the exhaust manifold, by inclining the cylinder axis of the engine longitudinally mounted on the vehicle so that the exhaust pipe installing surface turns obliquely downward; and is characterized by arranging this catalytic converter in the vicinity of a lower edge part of the exhaust outlet flange, by connecting the catalytic converter to an upstream side exhaust pipe so that the axis becomes substantially parallel to an output shaft of the engine, by forming the upstream side exhaust pipe on the upstream side more than the catalytic converter connected to the exhaust outlet flange, in a crank shape bent so as to further extend backward, after bending so as to approach the engine just after the exhaust outlet flange. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an engine exhaust system, and more particularly to an engine exhaust system capable of reducing a load applied to an exhaust manifold and improving a cooling performance of a turbocharger.

  An exhaust system of an engine mounted on a vehicle guides exhaust discharged from a combustion chamber by exhaust system parts such as an exhaust manifold, a turbocharger, an exhaust outlet pipe, a catalytic converter, and a muffler, and releases them to the outside. These exhaust system parts constituting the exhaust system are arranged at positions where a gap is provided between peripheral parts such as auxiliary machines because high-temperature exhaust flows. In addition, in an engine exhaust device having a tilted cylinder axis that is used in a so-called cabover type vehicle or the like, the catalytic converter is disposed at a position away from the output shaft of the engine due to the ground clearance. It will be.

In a conventional engine exhaust system, the cylinder axis of the engine is vertically mounted on a vehicle with the exhaust pipe mounting surface inclined obliquely downward, and the exhaust pipe mounting surface of the engine facing downward is disposed via an exhaust manifold. In some cases, a turbocharger is attached, and the turbocharger is disposed above an exhaust port plane passing through an axis passing through a plurality of exhaust ports.
JP-A-10-280967

Further, in the exhaust system of the conventional engine, the exhaust system is connected in parallel to the propulsion shaft driven by the engine mounted inclined on the vehicle, and a diameter-enlarged portion is provided in the middle part of the exhaust system, There is one in which a catalyst is accommodated in the enlarged diameter portion and the enlarged diameter portion is oriented in the vehicle width direction and the outward direction.
Japanese Patent Laid-Open No. 2001-3743

  By the way, in the exhaust system of an engine, in order to improve exhaust purification performance, it has been required to dispose a catalytic converter having a relatively large diameter and a long axial dimension immediately after the turbocharger.

  However, in an exhaust system for an engine mounted on a vehicle in an inclined manner, when the catalytic converter is disposed immediately downstream of the turbocharger when the catalytic converter is disposed downstream of the turbocharger, A catalytic converter having a relatively large diameter and a long axial dimension is disposed at a position away from the output shaft of the engine, which increases the load applied to the exhaust manifold. For this reason, it is necessary to take measures such as increasing the wall thickness in order to increase the rigidity of the exhaust manifold.

  In addition, in an exhaust system for an engine mounted on a vehicle at an inclination, a large catalytic converter is disposed immediately after the turbocharger, so that there is no space for running wind around the turbocharger. There was a problem that the turbocharger could not be cooled sufficiently.

  In the present invention, an engine and a transmission are vertically mounted on a vehicle, the cylinder axis of the engine is inclined so that an exhaust pipe mounting surface faces obliquely downward, and turbocharging is performed on the exhaust pipe mounting surface via an exhaust manifold. An engine in which an exhaust outlet flange of the turbocharger is disposed toward the rear of the vehicle and a catalytic converter is disposed in an exhaust pipe connected to the exhaust outlet flange and extending rearward of the vehicle In this exhaust system, the upstream exhaust pipe upstream of the catalytic converter connected to the exhaust outlet flange is bent so as to be close to the engine immediately after the exhaust outlet flange, and further extends rearward. The catalytic converter is connected to the upstream exhaust pipe so that the axis is substantially parallel to the output shaft of the engine. Characterized in that it is disposed the catalytic converter in the vicinity of the lower edge of said exhaust outlet flange.

  In the engine exhaust device of the present invention, after bending the upstream exhaust pipe upstream of the catalytic converter connected to the exhaust outlet flange of the turbocharger so as to be close to the engine immediately after the exhaust outlet flange, Further, it is formed in a crank shape bent to extend rearward, and the catalytic converter is connected to the upstream exhaust pipe so that the axis is substantially parallel to the output shaft of the engine, and this catalytic converter is connected to the lower edge of the exhaust outlet flange. Since the catalytic converter is disposed in the vicinity of the turbocharger and in the vicinity of the engine output shaft, the load on the exhaust manifold can be reduced, and the turbocharger can be reduced. It is possible to create a space through which the traveling wind passes behind the turbocharger and improve the cooling performance of the turbocharger.

The exhaust system for an engine according to the present invention reduces the load applied to the exhaust manifold by disposing the catalytic converter in the vicinity of the turbocharger and in the vicinity of the output shaft of the engine. It creates a space through which the traveling wind passes and improves the cooling performance of the turbocharger.
Embodiments of the present invention will be described below with reference to the drawings.

  1 to 7 show an embodiment of the present invention. 1-4, 2 is a vehicle, 4 is a right side frame, 6 is a left side frame, 8 is a mount member, 10 is an engine room, 12 is an engine, and 14 is a transmission. This vehicle 2 has two right and left side frames 4 and 6 oriented in the front-rear direction B on both sides in the width direction A, and the right and left side frames 4 and 6 are disposed below the engine room 10 in the vehicle 2. This is a so-called cab-over type in which the engine 12 and the transmission 14 are vertically mounted in the engine room 10 by being connected by a mount member 8 oriented in the width direction A.

  The mount member 8 is provided with a substantially horizontal extension portion 16 extending in the width direction A, and provided with support portions 18 and 20 extending obliquely upward at both ends of the extension portion 16, and extending to the tips of the respective support portions 18 and 20. Connecting portions 22 and 24 parallel to the portion 16 are provided. The mount member 8 is connected to the right and left side frames 4 and 6 by connecting bolts 26 and 28 at the connecting portions 22 and 24.

  The engine 12 mounted in the engine room 10 has a cylinder head 32 mounted above the cylinder block 30, a head cover 34 is attached to the cylinder head 30, and a crankshaft 36, which is an output shaft, is pivotally supported below the cylinder block 30. The transmission 14 is connected to the rear end of the cylinder block 30.

  The engine 12 is provided with an intake pipe mounting surface 38 on one side (upper side in FIG. 1) in a direction intersecting the cylinder axis C of the cylinder head 30 and on the other side in the direction intersecting with the cylinder axis C ( An exhaust pipe mounting surface 40 is provided on the lower side in FIG.

  The engine 12 has the cylinder axis C inclined so that the exhaust pipe mounting surface 40 faces obliquely downward, and is vertically mounted on the mount member 8 below the engine room 10 via the mount rubber 44 by the mount bracket 42. One end side of the mount bracket 42 is attached to the side surface below the cylinder block 30, and the other end side is attached to the support portion 20 on the left side of the extension portion 16 of the mount member 8 via a mount rubber 44.

  The intake device 46 of the engine 12 has an intake manifold 48 attached to an intake pipe attachment surface 38 that faces obliquely upward of the cylinder head 32.

  In the exhaust device 50 of the engine 12, a turbocharger 54 is attached to an exhaust pipe attachment surface 40 facing obliquely below the cylinder head 32 via an exhaust manifold 52. The turbocharger 54 is provided with an exhaust outlet flange 56 that is an exhaust outlet toward the rear of the vehicle 2, and an exhaust pipe 58 that extends rearward of the vehicle is connected to the exhaust outlet flange 56.

  The exhaust pipe 58 is provided with a catalytic converter 60 in the middle. As shown in FIG. 5, the catalytic converter 60 holds a catalyst 66 in a converter case 62 by a supporter 64. The exhaust pipe 58 is configured by an upstream exhaust pipe 68 and a downstream exhaust pipe 70 with the catalytic converter 60 interposed therebetween.

  The exhaust device 50 of the engine 12 evacuates exhaust gas from the engine 12 through an exhaust manifold 52, a turbocharger 54, an upstream exhaust pipe 68, a catalytic converter 60, a downstream exhaust pipe 70, and a rear exhaust pipe 86 described later. Through and discharged to the outside.

  As shown in FIGS. 5 to 7, the exhaust device 50 of the engine 12 connects the upstream exhaust pipe 68 upstream of the catalytic converter 60 connected to the exhaust outlet flange 56 to the engine 12 immediately after the exhaust outlet flange 56. After being bent so as to be close to each other, it is formed in a crank shape bent so as to extend further rearward. As shown in FIGS. 1 and 3, a catalytic converter 60 is connected to the upstream exhaust pipe 68 so that the axis L is substantially parallel to the output axis P of the crankshaft 36 of the engine 12. It is disposed in the vicinity of the lower edge of the exhaust outlet flange 56.

  Accordingly, the exhaust device 50 of the engine 12 reduces the load applied to the exhaust manifold 52 because the catalytic converter 60 is disposed in the vicinity of the turbocharger 54 and in the vicinity of the crankshaft 36 of the engine 12. Therefore, there is no increase in the weight of the exhaust manifold 52, and a space S through which the traveling wind passes can be created behind the turbocharger 54, and the cooling performance of the turbocharger 54 can be improved. Can be improved.

  The exhaust device 50 of the engine 12 forms an upstream exhaust pipe 68 upstream of the catalytic converter 60 by casting, and forms the catalytic converter 60 and the downstream exhaust pipe 70 downstream of the catalytic converter 60 from a sheet metal material. It is formed with. The upstream exhaust pipe 68 is integrally formed with a turbo mounting flange 72 in the upstream portion, a first sensor mounting portion 74 is integrally formed in the intermediate portion, and gradually decreases in diameter toward the catalytic converter 60 in the downstream portion. The upstream cone portion 76 is formed integrally. The upstream cone portion 76 is integrally formed with a stiffener mounting boss portion 78. The turbo attachment flange 72 is attached to the exhaust outlet flange 56 of the turbocharger 54. The upstream cone portion 76 is attached to the upstream portion of the converter case 62 of the catalytic converter 60.

  Further, the downstream exhaust pipe 70 is provided with a downstream cone portion 80 whose diameter gradually increases toward the catalytic converter 60 in the upstream portion, and a second sensor mounting portion 82 is provided separately in the intermediate portion, and is downstream. The connection flange 84 is provided separately in the part. The downstream cone portion 80 is attached to the downstream portion of the converter case 62 of the catalytic converter 60. A connection flange 88 upstream of the rear exhaust pipe 86 is connected to the connection flange 84.

  As shown in FIG. 7, the exhaust device 50 of the engine 12 forms a rising portion 90 that rises as it approaches the engine 12 at the lower edge of the exhaust outlet flange 56, and the catalytic converter 60 is placed below the rising portion 90. It is arranged.

  As a result, the exhaust device 50 of the engine 12 can reduce the load applied to the exhaust manifold 52 by arranging the catalytic converter 60 at a position closer to the exhaust outlet flange 56 to shorten the upstream exhaust pipe 68 as much as possible. In addition, the heat capacity of the upstream side exhaust pipe 68 can be reduced and the catalyst 66 can be activated early.

  In the exhaust device 50 of the engine 12, an upstream exhaust pipe 68 is formed by casting, and an upstream cone portion 76 that extends toward the catalytic converter 60 is integrally formed at a downstream portion of the upstream exhaust pipe 68. Yes. As shown in FIGS. 3 and 4, the exhaust device 50 has an upstream cone portion 76 connected to a mount bracket 42 attached to a side surface of the engine 12 via a stiffener 92. The stiffener 92 includes a first stiffener 92-1 attached to one end of the mount bracket 42, and a second stiffener 92-2 attached to one end of the stiffener attaching boss 78 of the upstream cone portion 76. The other end sides of the second stiffeners 92-1 and 92-2 are connected to each other.

  As a result, the exhaust device 50 of the engine 12 has the upstream cone portion 76 integrally formed with the upstream exhaust pipe 68 by casting, and is mounted on the mount bracket 42 of the engine 12 disposed close to the upstream cone portion 76. By connecting with the stiffener 92, the length of the stiffener 92 can be shortened and the supporting rigidity of the catalytic converter 60 can be improved.

  The exhaust system for an engine according to the present invention reduces the load applied to the exhaust manifold by disposing the catalytic converter in the vicinity of the turbocharger and in the vicinity of the output shaft of the engine. It is intended to create a space through which the traveling wind passes and improve the cooling performance of the turbocharger, and can be applied to a vehicle having an engine mounted vertically.

It is a rear view of an engine and a transmission showing an embodiment. It is a top view of the engine and transmission which show an Example. It is an engine and a side view of a transmission which show an Example. It is a bottom view of an engine and a transmission which show an example. It is a top view of an exhaust pipe and a catalytic converter showing an example. It is a side view of an exhaust pipe and a catalytic converter showing an embodiment. It is sectional drawing by the VII-VII line of FIG. 6 which shows an Example.

Explanation of symbols

2 Vehicle 4 Right side frame 6 Left side frame 8 Mount member 12 Engine 14 Transmission 30 Cylinder block 32 Cylinder head 34 Head cover 36 Crankshaft 40 Exhaust pipe mounting surface 42 Mount bracket 44 Mount rubber 50 Exhaust device 52 Exhaust manifold 54 Turbo supercharger Machine 56 Exhaust outlet flange 58 Exhaust pipe 60 Catalytic converter 68 Upstream exhaust pipe 70 Downstream exhaust pipe 72 Turbo mounting flange 76 Upstream cone section 78 Stiffener mounting boss section 80 Downstream cone section 90 Ascending section 92 Stiffener

Claims (3)

  The engine and transmission are mounted vertically in the vehicle, the cylinder axis of the engine is inclined so that the exhaust pipe mounting surface faces obliquely downward, and a turbocharger is attached to the exhaust pipe mounting surface via an exhaust manifold, An exhaust system for an engine in which an exhaust outlet flange of the turbocharger is disposed toward the rear of the vehicle, and a catalytic converter is disposed in an exhaust pipe connected to the exhaust outlet flange and extending rearward of the vehicle. The upstream exhaust pipe upstream of the catalytic converter connected to the exhaust outlet flange is bent so as to be close to the engine immediately after the exhaust outlet flange, and further bent to extend rearward. The catalyst converter is connected to the upstream exhaust pipe so that the axis is substantially parallel to the output shaft of the engine. The exhaust apparatus, characterized in that the converter is disposed in the vicinity of the lower edge of said exhaust outlet flange.   2. The engine exhaust according to claim 1, wherein a rising portion that rises toward the engine is formed at a lower edge portion of the exhaust outlet flange, and the catalytic converter is disposed below the rising portion. apparatus.   The upstream exhaust pipe is formed by casting, and an upstream cone portion extending toward the catalytic converter is integrally formed at a downstream portion of the upstream exhaust pipe, and the upstream cone portion is formed through the stiffener. 2. The engine exhaust device according to claim 1, wherein the exhaust device is connected to a mount bracket attached to a side surface of the engine.

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