JP2010120514A - Exhaust pipe structure of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve an exhaust pipe structure of a vehicle, which reduces pressure loss of exhaust gas running through an exhaust pipe, does not disturb work at an area behind the vehicle, in addition, can lower the temperature of exhaust gas by enhancing the diffusion effect of exhaust gas even in the case of diesel internal-combustion engine whose exhaust gas temperature is high. <P>SOLUTION: The structure of the vehicle is so formed as to be covered by outer plates, while exhaust pipes 30, 34 with tube-like cross section connected to the internal-combustion engine placed in the vehicle body are allocated up to the vehicle body sides. The terminal end portion 72 of the exhaust pipe is deformed flat so that it becomes approximately fan-shaped in plane view, with the axial line (m) of the flat terminal end portion being extended toward diagonally rear part with respect to the vehicle body side face (f). The flat terminal end portion 72 is made to have a form diagonally cut along the direction of the vehicle body side face, and the severed opening edge of the flat terminal end portion is allocated near the lower edge section of the vehicle body side face external plate 80. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to the structure of an exhaust pipe connected to an engine mounted on a vehicle, and more particularly, to an exhaust pipe connected to a diesel engine, which is an exhaust pipe end portion disposed close to an outer plate on the side of a vehicle body. Concerning structure.

The amount of particulate matter (hereinafter referred to as “PM”) emitted from diesel internal combustion engines mounted on vehicles such as trucks and buses is being regulated more and more year by year together with NO _x , CO and HC. A technique for collecting PM by a filter called a diesel particulate filter (DPF; Diesel Particulate Filter) to reduce PM emission has been developed.

Although PM trapped in the DPF is burned and discharged, the temperature of the exhaust gas discharged from the exhaust pipe is higher than usual, and there is a concern about the influence on the road surface and pedestrians. As a countermeasure, a method is adopted in which the end of the exhaust pipe is deformed into a fan shape to promote the mixing of the exhaust gas and the outside air during exhaust gas discharge, thereby rapidly reducing the temperature of the exhaust gas. .
Patent Document 1 (Japanese Patent Laid-Open No. 2006-207423) discloses an exhaust pipe structure employing the above method.

In Patent Document 1, as shown in FIG. 5, the tail pipe 01 attached to the end of the exhaust pipe is composed of a cylindrical circular pipe portion 02 and a flat end portion 03, and the end opening of the end portion 03 is opened. Flattened so that the edges are elliptical.
Then, experimental data is shown, and the aspect ratio a / b between the long dimension a and the short dimension b of the terminal opening edge is in the range of 1.5 to 5.0, and the spread angle on the long dimension side ( When flattened so that the taper angle θ) is 10 ° to 40 ° with respect to the axis of the tail pipe 01, the diffusion effect of the exhaust gas discharged from the exhaust pipe is improved, and the exhaust gas discharged It is disclosed that the temperature can be effectively reduced.

JP 2006-207423 A

In the conventional exhaust pipe including the exhaust pipe structure disclosed in Patent Document 1, the tail pipe is disposed below the rear bumper at the rear of the vehicle body. However, since the internal combustion engine to be mounted is disposed below the driver's seat in the front part of the vehicle body, in vehicles such as trucks and buses, it is necessary to extend the exhaust pipe from the front part of the vehicle body to the rear part of the vehicle body.
Therefore, there has been a problem that the pressure loss of the exhaust gas in the exhaust pipe becomes large and the flow rate of the exhaust gas decreases.

  Further, in a vehicle that performs work at the rear part of the vehicle body, for example, a nursing care vehicle that has a wheelchair lift at the rear part of the vehicle body, there is a problem that exhaust gas hits the operator and the like, causing the operator and the like to be uncomfortable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the prior art, and it is an object of the present invention to realize a vehicle exhaust pipe structure that reduces pressure loss of exhaust gas flowing in the exhaust pipe and does not hinder the work at the rear of the vehicle body. To do.
Further, as in a diesel internal combustion engine, even when the exhaust gas temperature is high, the diffusion effect of the exhaust gas exhausted from the exhaust pipe is enhanced and a vehicle exhaust pipe structure capable of lowering the exhaust gas temperature is realized. Objective.

In order to solve the above problems, an exhaust pipe structure for a vehicle according to the present invention includes:
A vehicle body structure covered with an outer plate is formed, and an exhaust pipe having a cylindrical cross section connected to an internal combustion engine mounted on the vehicle body is disposed up to the side of the vehicle body, and a terminal portion of the exhaust pipe is substantially fan-shaped in a plan view. To be flattened so that
The axis of the flat end portion is disposed obliquely rearward with respect to the side surface of the vehicle body, the flat end portion is cut obliquely along the side surface direction of the vehicle body, and the opening of the flat end portion is cut The edge is disposed close to the lower edge of the vehicle body side surface outer plate.

  In the exhaust pipe structure of the present invention, the end portion of the exhaust pipe is positioned at the lower edge of the side plate of the vehicle body, thereby shortening the length of the exhaust pipe and reducing pressure loss and working at the rear of the vehicle body. And so that it does not interfere with the installation of equipment. In addition, since the end portion of the exhaust pipe is not provided at the rear portion of the vehicle body, the departure angle can be set to the maximum without being affected by the position of the end portion of the exhaust pipe.

  Further, the exhaust pipe end portion is formed in a flat shape with long dimensions arranged in the horizontal direction in the same manner as in Patent Document 1, so that the exhaust gas is uniformly diffused from the end portion of the exhaust pipe in the horizontal direction without being unevenly distributed. In this way, the diffusion effect of exhaust gas is enhanced and the exhaust gas temperature is reduced.

  However, in a vehicle having a structure in which the entire vehicle body is covered with an outer plate, such as a bus, exhaust gas discharged from the exhaust pipe may be filled under the floor of the vehicle body. On the other hand, the size in the width direction of the vehicle is restricted by law, and the terminal portion of the exhaust pipe must not protrude outward from the side surface of the vehicle body.

Accordingly, in the present invention, the axis of the flat end portion is disposed obliquely rearward with respect to the side surface of the vehicle body, and the exhaust pipe is formed by cutting the flat end portion obliquely along the side surface direction of the vehicle body. The end portion of the engine can be prevented from projecting outward from the side of the vehicle body, and the exhaust gas discharge angle can be further expanded toward the outside of the vehicle body, thereby increasing the exhaust gas discharge angle and further improving the exhaust gas diffusion effect. it can.
Further, since the cutting opening edge of the flat end portion is disposed close to the lower edge portion of the vehicle body side surface outer plate, there is no possibility that the exhaust gas discharged from the exhaust pipe fills under the floor of the vehicle body.

  In the exhaust pipe structure of the present invention, the aspect ratio between the long dimension and the short dimension of the opening edge of the flat end portion is in the range of 1.5 to 5.0, and the expansion angle on the long dimension side is the exhaust. It is good to comprise so that it may be 10-40 degrees with respect to the axis line of a pipe | tube. By adopting such a configuration, as disclosed in Patent Document 1, the exhaust gas is discharged into the atmosphere while being diffused well from the end portion of the exhaust pipe, and the exhaust gas temperature can be effectively reduced. .

In the exhaust pipe structure of the present invention, the lower surface of the flat end portion of the exhaust pipe may be partially cut away along the horizontal cutting line from the opening edge toward the upstream side of the exhaust gas flow.
As a result, the angle of the exhaust gas flow discharged from the exhaust pipe with respect to the road surface is increased, so that the diffusion of the exhaust gas to the road surface side is expanded. As a result, it becomes easier to mix with the surrounding atmosphere, the temperature drop at the center of the exhaust gas is promoted, and the diffusion of the exhaust gas to the upper side is also reduced, so that the high temperature part is suppressed from spreading over a wide range, The risk of softening the road surface with heat can also be reduced.

Further, in the exhaust pipe structure of the present invention, the flat end portion of the exhaust pipe is manufactured separately from the exhaust pipe body, and the cutting opening edge of the flat end portion faces the vehicle body side outward with respect to the exhaust pipe body. It is good to position and join to the exhaust pipe body.
When the shape of the exhaust pipe is included up to the end portion, its axis has a complicated curve extending in three dimensions. Therefore, if the exhaust pipe is manufactured integrally including the end portion, the processing is not easy. Therefore, as described above, when the exhaust pipe main body and the terminal portion are manufactured separately, the processing becomes easy.

  Further, the end portion is manufactured separately, and the cutting opening edge of the end portion is positioned toward the outside of the vehicle body side surface or the road surface and joined to the exhaust pipe body, thereby facilitating positioning of the end portion.

  According to the exhaust pipe structure of a vehicle of the present invention, a vehicle body structure covered with an outer plate is formed, and an exhaust pipe having a cylindrical cross section connected to an internal combustion engine mounted on the vehicle body is disposed up to the side of the vehicle body. The end of the exhaust pipe is deformed into a flat shape so as to have a substantially fan shape in plan view, and the axis of the flat end is disposed obliquely rearward with respect to the side surface of the vehicle body. The exhaust pipe structure can be simplified and the exhaust gas can be simplified by forming a shape cut obliquely along the side surface direction and arranging the cutting opening edge of the flat end portion close to the lower edge portion of the vehicle body side surface outer plate. The pressure loss of the exhaust pipe can be reduced, and the exhaust pipe end is not provided at the rear of the vehicle body, so that installation and operation of equipment at the rear of the vehicle are not hindered, and the departure angle is set at the position of the end of the exhaust pipe. It can be set to the maximum without being affected.

  Further, by forming the cutting opening edge, the injection angle of the exhaust gas discharged from the flat end portion can be widened, so that the diffusion effect of the exhaust gas can be improved and the temperature can be lowered. Since the gas outlet is disposed close to the lower edge portion of the vehicle body side surface outer plate and is directed outward of the vehicle body side surface, there is no possibility that exhaust gas discharged from the exhaust pipe fills the floor of the vehicle body.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified.
Further, in the present description, the reference for indicating the direction represents the vertical, left and right, and front and rear in the state where the driver is seated.

  An embodiment of the present invention will be described with reference to FIGS. FIG. 1 shows a configuration of a small bus equipped with an exhaust pipe structure according to the present embodiment. In FIG. 1, the direction of arrow c is the front part of the vehicle body of the small bus 10, the front bumper 12 is provided at the front end of the vehicle body, and the rear bumper 14 is provided at the rear end of the vehicle body. The small bus 10 has a structure in which the entire vehicle body including both side surfaces 16 and 18 of the vehicle body is covered with an outer plate.

  The left and right front wheel storage portions 22 and 24 and the left and right rear wheel storage portions 26 and 28 are provided, and the diesel engine 20 is provided at the front portion of the vehicle body. One end of a front exhaust pipe 30 is connected to the diesel engine 20, and the other end of the front exhaust pipe 30 is connected to a rear exhaust pipe 34 via an exhaust gas purification device 32. The front exhaust pipe 30 and the rear exhaust pipe 34 are disposed in the front-rear direction of the vehicle body at a substantially central portion of the vehicle body below the chassis portion. The rear exhaust pipe 34 passes between the left and right rear wheel storage portions 26 and 28, and the end portion of the rear exhaust pipe 34 is disposed close to the vehicle body side skin between the right rear wheel storage portion 26 and the rear bumper 24. .

  The configuration of the diesel engine 20 and the exhaust gas purification device 32 will be described with reference to FIG. In FIG. 2, the diesel engine 20 in FIG. 2 is a common rail in-line four-cylinder diesel engine. In the engine 20, an electromagnetic fuel injection nozzle 42 is provided in each cylinder facing the combustion chamber 40. The fuel injection nozzle 42 for each cylinder is connected to a common rail 46 by a high-pressure pipe 44. The common rail 46 is configured to store high-pressure fuel pressurized to a constant pressure by a high-pressure pump (not shown).

An intake passage 50 is connected to the combustion chamber 40 via an intake valve 48, and intake air s is supplied from the intake passage 50 into the combustion chamber 40. A front exhaust pipe 30 is connected to the combustion chamber 40 via an exhaust valve 52.
An exhaust gas purification device 32 is installed in the front exhaust pipe 30. The exhaust gas purification device 32 includes a diesel particulate filter (DPF) 54 made of a ceramic filter, and a pre-stage oxidation catalyst 56 installed upstream thereof. In addition, the rear stage oxidation catalyst 58 is disposed downstream of the DPF 54.
The DPF 54 and the upstream oxidation catalyst 56 on the upstream side are housed in the same cylindrical casing 62 and unitized to form a continuous regeneration type DPF device 60. The rear-stage oxidation catalyst 58 is housed in another cylindrical casing 64.

This continuous regeneration type DPF device 60 causes the unoxidized fuel and oil of PM to be burned by the pre-stage oxidation catalyst 56 by the action of the pre-stage oxidation catalyst 56, and the DPF 54 installed downstream of the pre-stage oxidation catalyst 56 is heated to a high temperature. The soot component captured by the DPF 54 is automatically continuously burned and removed.
Further, HC and CO that have passed through the front-stage oxidation catalyst 56 are collected again by the rear-stage oxidation catalyst 58, where the HC and CO are purified.

  Further, in the continuous regeneration type DPF device 60, the particulate matter (PM) deposited on the DPF 54 when the temperature of the DPF 54 and the pre-stage oxidation catalyst 56 is low and the continuous regeneration type DPF device 60 cannot perform the continuous regeneration function. ) Is forcibly removed by combustion.

  That is, during traveling such as repeated stopping and starting, or continuous traffic jams, the exhaust temperature does not rise sufficiently, so that continuous regeneration may not be performed automatically during traveling. In such a case, when the PM accumulation amount reaches a certain amount, the DPF indicator lamp or the like issues an alarm to notify the driver, so that the driver stops the vehicle in a safe place, and the DPF cleaning switch or the like. By operating the manual regeneration switch, forced regeneration with an external heat source is performed.

For example, in this forced regeneration, after the main injection for main combustion is performed by the fuel injection nozzle 42, additional injection of fuel, that is, post injection, is performed by the injection nozzle 42 in the expansion stroke or the exhaust stroke. The fuel injection control is performed so as to raise the fuel consumption.
By this post-injection, the exhaust gas temperature rises, the pre-stage oxidation catalyst 56 is activated, and the DPF 54 is heated by the heat of oxidation, so that the soot on the DPF 54 is forcibly burned and removed.

As shown in FIG. 1, the exhaust gas e passes through the exhaust gas purification device 32 and is then discharged from the rear exhaust pipe 34 to the atmosphere.
In this way, in the vehicle provided with the continuous regeneration type DPF device 60, exhaust gas having a temperature higher than that of normal exhaust gas is exhausted from the rear exhaust pipe 34.

  Next, the configuration of the exhaust pipe end portion will be described with reference to FIGS. 3 and 4. 3 and 4, a tail pipe 72 is joined to the exhaust pipe main body 70 at the end of the rear exhaust pipe 34. The tail pipe 72 is manufactured separately from the exhaust pipe main body 70, and is fitted and welded to the distal end portion of the exhaust pipe main body 70. The axis m of the tail pipe 72 is disposed obliquely rearward with respect to the right side surface f of the vehicle body.

  The exhaust pipe body 70 has a circular cross-sectional shape d. The tail pipe 72 has a circular cross section at the joint with the exhaust pipe main body 70, but has a flat shape gradually spreading in the horizontal direction toward the tip. That is, it has a fan-like shape in plan view, and its end surface shape is an ellipse e before the formation of cut surfaces g and i described later. The shape of the ellipse e is formed so that the aspect ratio a / b of the long dimension a and the short dimension b is in the range of 1.5 to 5.0. Moreover, it shape | molds so that this fan-shaped expansion angle (theta) may be in the range of 10-40 degrees.

  Further, one side of the tail-shaped long dimension side of the tail pipe 72 has a cut surface g cut along a cutting line in the vicinity of the right side surface f of the vehicle body and parallel to the right side surface f of the vehicle body. The lower part of the tail pipe 72 has a shape cut along a horizontal cutting line h. Therefore, the lower portion of the tail pipe 72 has a shape cut out at the cut surface i. And as shown in FIG. 4, it arrange | positions adjacent to the lower edge part of the outer plate | board 80 so that the cut surface g may substantially correspond to the outer plate | board 80 of the vehicle body right side surface.

The tail pipe 72 is manufactured separately from the exhaust pipe main body 70 of the rear exhaust pipe 34. The tail pipe 72 is fitted to the exhaust pipe main body 70 by a fitting portion 74, and the cutting surface g faces outward from the right side of the vehicle body. After the surface i is positioned so as to face the road surface, it is welded.
In FIG. 3 (b), the end surface of the tail pipe 72 viewed from the X view is composed of a non-cut surface j constituting a part of the ellipse e, a cut surface g, and a cut surface i.

3 and 4, broken lines k ₁ and k ₂ are discharged from a flat tail pipe (for example, a tail pipe having a configuration disclosed in Patent Document 1) before being cut by the cutting surface g and the cutting surface i. The outer edge of the exhaust gas flow is shown. Broken lines l ₁ and l ₂ indicate the outer edges of the exhaust gas flow discharged from the tail pipe 72 according to the present embodiment after being cut at the cut surface g and the cut surface i.

  As shown in the figure, the tail pipe 72 according to the present embodiment diffuses the exhaust gas in the horizontal direction, and can promote the temperature reduction of the exhaust gas. Further, since the exhaust gas can be ejected deeply downward toward the road surface, the exhaust gas flow directed downward increases, so that the exhaust gas flow directed downward causes the deleted portion by the cut surface i as in the prior art. Compared to the end portion structure without the gas, the diffusion of the exhaust gas is increased, and it becomes easy to mix with the surrounding outside air.

Accordingly, the temperature drop at the center of the exhaust gas flow is promoted, and further, the diffusion of the exhaust gas upward is reduced, so that the high temperature part can be prevented from spreading over a wide range.
Moreover, since the cut surface i is cut by a horizontal line substantially parallel to the road surface, the opening area opened in the road surface direction can be maximized. For this reason, the exhaust gas is effectively diffused to the road surface side, the temperature reduction of the central portion of the exhaust gas flow can be further promoted, and the high temperature portion is suppressed from spreading over a wide range. Therefore, as shown in FIG. 2, even when the exhaust gas purification device 32 is connected to the diesel engine 20 and the exhaust gas temperature is high, the exhaust gas temperature can be rapidly reduced.

  In addition, the tail pipe 72 is disposed close to the outer plate 80 on the right side of the vehicle body, and the exhaust gas outlet is directed outward from the right side of the vehicle body, so that the exhaust gas does not accumulate inside the vehicle body and diffuses the exhaust gas. It can be discharged outside the vehicle body.

  The axis of the rear exhaust pipe 34 including the tail pipe 72 has a complicated shape bent in a three-dimensional direction. In this embodiment, the tail pipe 72 is manufactured separately from the exhaust pipe main body 70 and cut. After the tail pipe 72 is positioned by adjusting the orientation of the surface g and the cut surface i, the tail pipe 72 is welded to the exhaust pipe body 70, so that the tail pipe 72 can be easily positioned and the rear exhaust The entire tube can be easily attached to the car body.

Further, since the end portion of the rear exhaust pipe 34 is disposed between the rear wheel storage portion 26 and the rear bumper 14 and close to the right side surface f of the vehicle body, the departure angle is not affected by the position of the exhaust pipe end portion. It can be set to the maximum.

  According to the present invention, the pressure loss of the exhaust gas flowing in the exhaust pipe is reduced, the work at the rear of the vehicle body is not hindered, and the exhaust gas is exhausted even when the exhaust gas temperature is high as in a diesel internal combustion engine. A vehicle exhaust pipe structure capable of increasing the gas diffusion effect and reducing the temperature of the exhaust gas can be realized.

1 is a plan view explanatory view of a vehicle showing an exhaust pipe structure according to an embodiment of the present invention. It is explanatory drawing which shows the internal combustion engine and exhaust pipe structure which are mounted in the vehicle. The exhaust pipe termination | terminus part of the said embodiment is shown, (a) is a top view, (b) is a X view side view in (a) figure. It is a perspective view which shows the exhaust pipe termination | terminus part of the said embodiment. It is a top view which shows the conventional exhaust pipe termination | terminus part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Small bus 20 Diesel engine 30 Front exhaust pipe 32 Exhaust gas purification device 34 Rear exhaust pipe 70 Exhaust pipe main body 72 Tail pipe (exhaust pipe terminal part)
80 Car body side skin a Long dimension b Short dimension g, i Cut surface m Exhaust pipe axis θ Expansion angle

Claims (4)

A vehicle body structure covered with an outer plate is formed, and an exhaust pipe having a cylindrical cross section connected to an internal combustion engine mounted on the vehicle body is disposed up to the side of the vehicle body, and a terminal portion of the exhaust pipe is substantially fan-shaped in a plan view. To be flattened so that
The axis of the flat end portion is disposed obliquely rearward with respect to the side surface of the vehicle body, the flat end portion is cut obliquely along the side surface direction of the vehicle body, and the opening of the flat end portion is cut An exhaust pipe structure for a vehicle, characterized in that the edge is disposed close to the lower edge of the vehicle body side skin.   The aspect ratio of the long dimension and the short dimension of the opening edge of the flat end portion is in the range of 1.5 to 5.0, and the expansion angle on the long dimension side is 10 with respect to the axis of the exhaust pipe. The exhaust pipe structure for a vehicle according to claim 1, wherein the exhaust pipe structure is ˜40 °.   2. The exhaust pipe structure for a vehicle according to claim 1, wherein a part of a lower surface of the flat end portion is cut out along a horizontal cutting line from an opening edge toward an upstream side of an exhaust gas flow.   The flat end portion is manufactured separately from the exhaust pipe main body, and the cutting opening edge of the flat end portion is positioned toward the outer side of the vehicle body with respect to the exhaust pipe main body and joined to the exhaust pipe main body. The exhaust pipe structure for a vehicle according to any one of claims 1 to 3.

Images