JP2008260472A - Front structure of vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide front structure of a vehicle in which an engine is laterally arranged in an engine compartment in front of the vehicle, an inlet pipe is allocated in front of the engine and an exhaust pipe is located rear of the engine, capable of improving the exhaust efficiency of the engine and enhancing the crash safety of the vehicle without installing longitudinal space between the engine and a dash panel. <P>SOLUTION: The front portion of a tunnel part 6 is formed with a tunnel expansion portion 20 projecting upward and in the vehicle width direction. The tunnel expansion portion 20 is largely and highly formed to lay out the exhaust system components extending from the exhaust manifold 9 toward the rear inside thereof (the outward of a cabin). <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a front structure of a vehicle, and in particular, a front portion of a vehicle in which an engine is disposed horizontally in an engine room at the front of the vehicle, an intake pipe is disposed in front of the engine, and an exhaust pipe is disposed behind the engine. Concerning structure.

  Conventionally, in general vehicles, a front engine / front drive system (hereinafter referred to as FF system) is often employed in order to secure as much cabin space as possible. At this time, since the engine output shaft and the drive shaft are positioned in parallel in terms of driving efficiency, the engine is normally disposed horizontally (a position where the cylinder row faces in the vehicle width direction).

  In recent years, in order to reduce exhaust gas emissions, many vehicles adopt a rear exhaust layout in which an exhaust pipe is arranged on the rear side of the engine to shorten the distance from the exhaust port to the catalyst. Yes.

  For example, Patent Document 1 below discloses a vehicle that employs a rear exhaust layout in which an exhaust pipe is disposed behind the engine in an FF vehicle that is installed horizontally on the engine.

JP-A-11-198663

  By the way, in order to increase the exhaust efficiency of the engine and increase the engine output, it is desirable to lay out the exhaust pipe so as to extend as straight as possible.

  However, the exhaust pipe of the vehicle described in the above-mentioned Patent Document 1 has a dash panel located rearward, so that it is bent vertically downward from the upper part of the engine, and horizontally at the lower end at the rear side. It is laid out in a substantially crank shape so as to be bent.

  For this reason, the vehicle engine described in Patent Document 1 has a problem that the exhaust pipe is bent in a complicated manner, the exhaust efficiency cannot be increased, and the engine output cannot be sufficiently increased.

  Further, if the exhaust pipe is laid out behind the engine, the exhaust pipe presses the dash panel due to the retreat of the engine at the time of a vehicle collision, and there is a possibility that deformation of the dash panel toward the rear side is increased.

  As a structure for preventing such a problem, it is conceivable to arrange the engine as far as possible in the engine room and to provide a space in the front-rear direction between the engine and the dash panel to ensure a sufficient exhaust pipe layout space.

  However, if a space in the front-rear direction is provided between the dash panel and the engine, the dash panel is located at the rear, so that the cabin space is significantly reduced or the engine is located on the front side of the vehicle, A new problem arises in that the weight balance of the vehicle deteriorates and the handling stability deteriorates.

  Therefore, the present invention provides a vehicle front structure in which an engine is disposed horizontally in an engine room at the front of the vehicle, an intake pipe is disposed in front of the engine, and an exhaust pipe is disposed behind the engine. It is an object of the present invention to provide a vehicle front structure that can increase the exhaust efficiency of an engine and increase the collision safety of a vehicle without providing a space in the front-rear direction between the panels.

  The vehicle front structure according to the present invention is a vehicle in which an engine is disposed horizontally in an engine room at the front of the vehicle, an intake pipe is disposed in front of the engine, and an exhaust pipe is disposed behind the engine. A dash panel having a front structure, wherein the exhaust pipe is formed so as to extend substantially linearly at a predetermined inclination angle from the exhaust port at the top of the engine to the lower rear side of the vehicle. A tunnel portion that protrudes toward the vehicle interior side and extends in the vehicle front-rear direction is formed at the vehicle width direction center of the connection portion between the floor panel and the floor panel, and protrudes upward along the exhaust pipe at the front portion of the tunnel portion. Thus, a tunnel enlargement portion having an upper wall surface inclined so as to correspond to the inclination angle of the exhaust pipe is formed.

According to the above configuration, by forming the tunnel expansion portion that protrudes largely upward at the front portion of the tunnel portion, the substantially straight exhaust pipe inclined downward and rearward is formed inside (downward) of the tunnel expansion portion. Can be laid out.
For this reason, it is possible to dispose the engine behind the engine without bending the exhaust pipe while disposing the engine close to the dash panel. Further, by positioning the exhaust pipe inside the tunnel expansion portion, the exhaust pipe can be embedded in the tunnel portion at the time of a vehicle collision.

In one embodiment of the present invention, the exhaust port of the engine is set at a position below the extended line of the inclination angle of the upper wall surface of the tunnel enlarged portion.
According to the above configuration, the exhaust port of the engine is set at a position below the extended line of the inclination angle of the upper wall surface of the tunnel expansion portion, so that the exhaust pipe can be straightened more reliably inside the tunnel expansion portion. Can be laid out. In addition, it becomes easier to guide the exhaust pipe that moves backward in the event of a vehicle collision into the tunnel expansion section.
Therefore, the exhaust efficiency of the engine can be further increased, and the exhaust pipe can be reliably prevented from affecting the dash panel side at the time of a vehicle collision.

In one embodiment of the present invention, a catalyst or flexible tube is provided in the middle of the exhaust pipe, and the catalyst or flexible tube is disposed at a position corresponding to the tunnel enlarged portion.
According to the said structure, the catalyst or flexible tube with a large occupation space can be laid out using the comparatively big space in a tunnel expansion part.
Therefore, it is not necessary to install a catalyst or flexible tube having a large occupied space between the engine and the dash panel, and collision safety can be further improved.
In particular, in the case of a catalyst, the air around the heated catalyst (hot air) can be discharged to the rear side of the vehicle by using a tunnel portion extending in the front-rear direction. Can be prevented.

In one embodiment of the present invention, a steering mechanism for steering the front wheels is arranged on the vehicle front side of the catalyst.
According to the above configuration, since the steering mechanism is arranged on the vehicle front side of the catalyst, it is difficult for hot air around the catalyst to flow through the steering mechanism while the vehicle is traveling.
Therefore, the heat damage by the catalyst to the steering mechanism can be suppressed, and the durability of the steering mechanism can be enhanced.

In one embodiment of the present invention, the engine is inclined so that the upper part of the engine is located on the vehicle rear side.
According to the said structure, a space can be ensured in the engine upper part front and the engine lower part rear by the engine being inclined and arranged (slant arrangement) on the vehicle rear side. Further, the position of the exhaust port of the engine can be lowered.
For this reason, the arrangement space of the intake pipe arranged in front of the engine can be expanded. Further, the front differential disposed behind the engine can be disposed on the vehicle front side. Furthermore, since the position of the exhaust port is lowered, the exhaust pipe can be more easily laid out in a straight line, and the exhaust efficiency of the engine can be increased. In addition, since the distance to the catalyst can be shortened, early activation of the catalyst can be achieved.
Therefore, the performance of the intake / exhaust system of the rear exhaust engine can be enhanced by tilting the engine to the rear, and the amount of overhanging of the vehicle can be reduced, so that the vehicle steering performance can also be enhanced.

According to the present invention, the engine can be disposed close to the dash panel, but can be disposed behind the engine without bending the exhaust pipe. Further, by positioning the exhaust pipe inside the tunnel expansion portion, the exhaust pipe can be embedded in the tunnel portion at the time of a vehicle collision.
Therefore, in the front structure of a vehicle in which the engine is disposed horizontally in the engine room in the front of the vehicle, the intake pipe is disposed in front of the engine, and the exhaust pipe is disposed in the rear of the engine, the space between the engine and the dash panel is Without providing a space in the front-rear direction, the exhaust efficiency of the engine can be increased, and the collision safety of the vehicle can be increased.

Hereinafter, the vehicle front structure of the present embodiment will be described with reference to the drawings.
First, the overall structure of the front structure of the vehicle will be described with reference to FIGS. 1 is a perspective view showing a characteristic part of a vehicle front structure, FIG. 2 is an overall side view of the vehicle front structure, FIG. 3 is an overall front view excluding an engine, and FIG. 4 includes a body frame and the like. FIG. 5 is an overall bottom view including a vehicle body frame and the like.

  As shown in FIG. 2, the front portion of the vehicle includes an engine room ER in which the engine 7 is disposed and a vehicle room CR formed behind the engine room ER.

  The engine room ER is defined by a bonnet 1 extending in the vehicle front-rear direction with the upper part downward, the front part is defined by a front grill 2 and a front bumper 3, and the rear part is extended in a vertical direction. It is divided and constituted by.

  The vehicle compartment CR has an upper portion defined by a roof panel (not shown), a front portion defined by the dash panel 4 described above, a lower portion a floor panel 5 extending in the vehicle longitudinal direction, and a tunnel portion 6 extending in the vehicle longitudinal direction. It is divided and configured.

  Among these, an in-line four-cylinder I-type engine 7 is disposed horizontally in the engine room ER. That is, the I-type engine 7 having four cylinders is arranged so that the cylinder row extends in the vehicle width direction. The engine 7 is arranged to be inclined (slant) to the rear side so that the engine upper portion 7a is located slightly on the rear side. This inclination angle α is set to about 15 °.

  Further, an intake manifold 8 that introduces intake air into each cylinder is installed in front of the engine upper portion 7a, and an exhaust manifold 9 that exhausts exhaust gas from each cylinder is installed behind the engine upper portion 7a.

  The intake manifold 8 is curved so as to surround the surge tank 10 extending in the cylinder row direction, and each has a predetermined intake passage length.

  On the other hand, the exhaust manifold 9 is formed to extend rearward and obliquely downward from the exhaust port 11 on the rear surface of the engine upper portion 7a inclined rearward.

Further, as shown in FIG. 4, a transmission 12 is disposed on one side of the engine 7 (the left side in FIG. 4). A front differential 13 is disposed at the rear of the transmission 12.
The transmission 12 is a so-called horizontal type transmission 12 in which an input shaft and an output shaft (not shown) extend in the vehicle width direction. The output of the engine 7 is directly changed by a helical gear or the like (spur gear) without changing the direction. This is transmitted to the front differential 13.

The front differential 13 is configured to transmit the output from the transmission 12 to the left and right front wheels 14 and 14, and defines the output position of a drive shaft (not shown). The drive shaft extends in the vehicle width direction and transmits driving force to the front wheels 14 and 14 installed on both sides of the vehicle.
As shown in FIG. 2, a radiator 15 is installed in front of the engine room ER in front of the engine 7. A steering rack 16 of a steering mechanism for steering the front wheels 14 is installed behind the engine lower portion 7b.

  As shown in FIG. 3, the dash panel 4 that constitutes the front wall of the passenger compartment is composed of a panel body that extends in the up-down direction and in the vehicle width direction. A tunnel opening 17 connected to the tunnel portion 6 is provided in the center of the vehicle width of the dash panel 4.

  As shown in FIG. 1, the floor panel 5 that constitutes the passenger compartment floor surface extends rearward from the lower end of the dash panel 4 in the vehicle longitudinal direction and extends in the vehicle width direction. Further, side sills 18 and 18 which are vehicle body skeleton members extend in the vehicle front-rear direction at both side ends of the floor panel 5 (see FIG. 5).

  At the center in the vehicle width direction of the floor panel 5, as shown in FIG. 1, a tunnel portion 6 extending in the vehicle front-rear direction that protrudes upward (in the vehicle interior) in a substantially hat shape is formed. The width W in the vehicle width direction and the height H in the vertical direction of the tunnel portion 6 are set to such an extent that a single exhaust pipe (rear exhaust pipe 19) is disposed inside (outside the cabin).

  At the front part of the tunnel part 6, a tunnel expansion part 20 that protrudes further upward and in the vehicle width direction is formed. The enlarged tunnel portion 20 is formed large and high in the interior (outside the vehicle compartment) so that the exhaust system components extending rearward from the exhaust manifold 9 can be laid out.

  That is, corresponding to the inclination of the exhaust manifold 9 described above, the upper wall surface 20a that extends obliquely from the upper part of the dash panel 4 to the rear of the vehicle, and the width corresponding to the four exhaust manifolds 9 to the rear of the vehicle toward the center. The side wall surfaces 20b and 20c that extend at an angle form a tunnel enlarged portion 20 that secures a large internal space S, and the direct catalystists 21, 21 and Y located behind the exhaust manifold 9 in the internal space S. The components of the exhaust system such as the character exhaust pipe 22 are laid out.

The components of the exhaust system will be described in detail.
As shown in FIG. 4, an exhaust manifold 9 (9a, 9b, 9c, 9d) is disposed behind the engine 7. The exhaust manifold 9 is configured such that four exhaust manifolds 9a, 9b, 9c, and 9d are temporarily gathered into two to avoid exhaust interference. That is, since the combustion timing is set as the first cylinder E1, the third cylinder E3, the fourth cylinder E4, and the second cylinder E2, the exhaust manifold 9a of the first cylinder E1 and the exhaust manifold of the fourth cylinder E4 at both ends. 9d is configured such that the exhaust manifold 9b of the center second cylinder E2 and the exhaust manifold 9c of the third cylinder E3 are respectively assembled on the downstream side.

  Corresponding to the respective exhaust manifolds 9a, 9b, 9c, 9d, two substantially cylindrical straight catalyst members 21, 21 are provided side by side in the vehicle width direction. Although this direct catalyst 21 is composed of a three-way catalyst, it is installed at this position mainly for purifying HC (hydrocarbon) and CO (carbon monoxide) during cold. .

  Behind this, a substantially Y-shaped Y-shaped exhaust pipe 22 that collects two pipe lines into one is provided. When the exhaust gas passes through the direct catalyst 21, it is difficult to be affected by the exhaust interference, so that the exhaust system is assembled at this position.

  Behind this, a substantially cylindrical flexible joint 23 is provided so that roll vibrations of the engine 7 and the like are absorbed by the flexible joint 23. For this reason, the exhaust system to the flexible joint 23 swings together with the engine 7.

  A substantially cylindrical underfoot catalyst 24 is provided behind the flexible joint 23. The underfoot catalyst 24 is also composed of a three-way catalyst, but is mainly installed at this position in order to purify NOx (nitrogen oxide).

  At the rear (downstream), a single rear exhaust pipe 19 is formed so as to extend in the tunnel 6 toward the rear side of the vehicle, and a silencer (not shown) is provided at the rear end to discharge exhaust gas to the rear of the vehicle. It is configured to do.

  Among the components of the exhaust system configured as described above, as shown in FIG. 4, the direct catalyst 21 and the Y-shaped exhaust pipe 22 are provided so as to correspond to the tunnel expansion portion 20 at the front portion of the tunnel portion 6. Yes.

  This is because, as described above, the exhaust manifold 9 is formed so as to extend obliquely downward in a substantially straight line from the exhaust port 11 of the engine upper portion 7a in a side view, and thus the direct catalyst 21 and the Y-shaped exhaust pipe. This is because 22 is arranged to extend obliquely downward corresponding to the linear arrangement.

  Thus, the exhaust efficiency of the engine 7 can be increased by arranging the exhaust systems so as to be arranged in a substantially straight line.

  Thus, by forming the tunnel enlarged portion 20 at the front portion of the tunnel portion 6, it becomes possible to lay out the components of the exhaust system in a straight line.

  The positional relationship between the tunnel enlarged portion and the components of the exhaust system will be described in more detail with reference to FIGS. 6 is a detailed side sectional view in the vicinity of the tunnel enlarged portion, and FIG. 7 is a detailed plan sectional view in the vicinity of the tunnel enlarged portion.

  As shown in FIG. 6, the upper wall surface 20a of the tunnel expanding portion 20 is formed so as to incline downward from the vicinity of the upper portion 4a of the dash panel 4 with a predetermined inclination angle β (for example, β = 46 °). This inclination angle β is set to a value larger than the inclination angle γ (for example, γ = 23 °) of the direct catalyst 21. This is because, as will be described later, in the event of a vehicle collision, the exhaust system is likely to enter the tunnel portion 6 as much as possible along the upper wall surface 20a.

  Further, the engine 7 and the exhaust port 11 are set to be positioned below the extended line L of the inclination angle of the upper wall surface 20a. This is because when the vehicle collides, the exhaust manifold 9 can be more easily guided to the space 6A of the tunnel portion 6 and the components of the exhaust system can be more easily laid out in a straight line.

  On the other hand, as shown in FIG. 7, the side wall surfaces 20 b and 20 c of the tunnel portion 6 are formed so as to be inclined in a substantially square shape spreading in the vehicle width direction toward the vehicle front side.

  The side wall surfaces 20b and 20c are also formed so as to be inclined with a predetermined inclination angle δ (for example, δ = 26 °). The inclination angle δ is also larger than the inclination angles ε1, ε4 (for example, ε1 = 10 °, ε4 = 20 °) of the exhaust manifolds 9a, 9b of the first cylinder E1 and the fourth cylinder E4.

  Further, the vehicle width direction width A of the front end portions of the side wall surfaces 20 b and 20 c is also set wider (longer) than the vehicle width direction width B of both side ends of the exhaust manifold 9.

  As will be described later, this setting is made in order to make it easier to guide the exhaust manifold 9 into the internal space S of the tunnel expansion portion 20 and to make it easier to fit in the event of a vehicle collision.

  The behavior at the time of a vehicle collision will be described with reference to FIGS.

  FIG. 8 is an explanatory diagram showing the behavior at the time of a vehicle collision in a side view, in which (a) shows the initial stage of the collision, (b) shows the middle stage of the collision, and (c) shows the late stage of the collision. FIG. 9 is an explanatory view showing the behavior at the time of a vehicle collision in a plan view, where (a) shows the initial stage of the collision and (b) shows the late stage of the collision.

  As shown in FIG. 8A, when a collision load F is applied from the front of the vehicle, the engine 7 moves backward and the exhaust manifold 9 also moves backward. At this time, since the upper wall surface 20a of the tunnel expansion portion 20 is inclined, the exhaust manifold 9 and the like come into contact with each other and the exhaust system components (9, 21, 22, 23, 24) are guided downward. become. At this time, since the rear flexible joint 23 is relatively fragile, bending occurs at the portion of the flexible joint 23, and the exhaust system components (9, 21, 22, 23, 24) are more expanded in the tunnel expansion portion. 20 and the internal space S, 6A of the tunnel part 6 are easily submerged.

  As shown in (b), in the middle of the collision, the exhaust manifold 9 is guided downward by the upper wall surface 20a, so that the upper portion 7a of the engine 7 is further inclined to the rear side. The components (9, 21, 22, 23, 24) can easily enter the tunnel enlargement unit 20 and the tunnel unit 6.

  As shown in (c), in the late stage of the collision, almost all the exhaust system components (9, 21, 22, 23, 24) of the engine 7 will sink into the tunnel expanding portion 20 and the tunnel portion 6, and the dash. The panel 4 is not affected by the components of the exhaust system (9, 21, 22, 23, 24).

  As shown in FIG. 9 (a), at the time of a vehicle collision, the intake manifold 8 is located on the vehicle front side of the transmission 12, so that the engine 7 side is more easily retracted. While rotating slightly to the side (clockwise in FIG. 9), the vehicle moves backward toward the rear of the vehicle. For this reason, the position of the exhaust manifold 9 is changed to the center side in the vehicle width direction, so that the exhaust manifold 9 is easily fitted into the internal space S of the tunnel enlarged portion 20.

  In addition, as described above, the direct catalyst 21 is provided at the position where the exhaust manifolds 9 are gathered, and the direct catalyst 21 is installed in the tunnel expansion portion 20, so that the four exhaust manifolds can be more reliably installed. 9 becomes easy to fit in the tunnel expansion part 20.

  Further, since the side wall surfaces 20b and 20c are inclined in the shape of a letter C, the exhaust manifold 9 is likely to come into contact with the side wall surfaces 20b and 20c as the vehicle moves backward toward the rear side of the vehicle. 21, 22, 23, 24) are more easily fitted into the tunnel portion 6.

  As shown in (b), at the later stage of the collision, the exhaust manifold 9 is retracted in such a manner that almost all of the exhaust manifold 9 is fitted into the tunnel enlarged portion 20, and the exhaust system components (9 , 21, 22, 23, 24) does not affect the dash panel 4.

Next, the effect of this embodiment is demonstrated.
In the vehicle front structure of this embodiment, the components (9, 21, 22, 23, 24) of the exhaust system are substantially arranged at a predetermined inclination angle γ from the exhaust port 11 of the engine upper part 7a to the vehicle rear side downward. A tunnel portion 6 is formed so as to extend in a straight line and protrudes toward the vehicle interior side and extends in the vehicle front-rear direction at the center in the vehicle width direction between the dash panel 4 and the floor panel 5. A tunnel having an upper wall surface 20a that protrudes greatly upward along the exhaust system components and is inclined to correspond to the inclination angle γ of the exhaust system component (21) (inclination angle β). An enlarged portion 20 is formed.

As a result, the exhaust system components (9, 21, 22, 23, 24) inclined rearwardly downward can be laid out inward (downward) of the tunnel enlarged portion 20.
For this reason, it is possible to arrange the engine 7 behind the engine 7 without greatly bending the components (9, 21, 22, 23, 24) of the exhaust system while arranging the engine 7 close to the dash panel 4. . Further, by positioning the exhaust system components inside the tunnel enlargement portion 20, the exhaust system components can be embedded in the tunnel portion 6 in the event of a vehicle collision.
Therefore, in the front structure of the vehicle in which the engine 7 is disposed horizontally in the engine room ER at the front of the vehicle, the intake manifold 8 is disposed in front of the engine 7, and the exhaust manifold 9 is disposed behind the engine 7. Without providing a space in the front-rear direction between the engine 7 and the dash panel 4, the exhaust efficiency of the engine 7 can be increased and the collision safety of the vehicle can be increased.

In this embodiment, the engine 7 and the exhaust port 11 of the engine 7 are set below the extended line L of the inclination angle β of the upper wall surface 20a of the tunnel expanding portion 20 (see FIG. 6).
As a result, the exhaust system components (9, 21, 22, 23, 24) can be more reliably laid out in a substantially straight line below the tunnel expansion portion 20. In addition, the exhaust system components (9, 21, 22, 23, 24) retreating at the time of a vehicle collision can be easily guided by the internal space S of the tunnel expanding portion 20 and the internal space 6A of the tunnel portion 6.
Therefore, the exhaust efficiency of the engine 7 can be further increased, and the components (9, 21, 22, 23, 24) of the exhaust system can be reliably prevented from affecting the dash panel 4 side at the time of a vehicle collision.

Further, in this embodiment, a direct catalyst 21 is provided in the middle of the exhaust system components, and the direct catalyst 21 is disposed at a position corresponding to the tunnel enlargement unit 20.
Thereby, the direct catalystist 21 with a large occupied space can be laid out using a relatively large space in the tunnel enlargement unit 20.
Therefore, it is not necessary to install the direct catalyst 21 having a large occupied space between the engine 7 and the dash panel 4, and the collision safety can be further improved.
In particular, since the direct catalyst 21 heats the air around the direct catalyst 21, this air (hot air) can be discharged to the vehicle rear side using the tunnel portion 6 extending in the front-rear direction. The heat damage around the list 21 can be prevented.

In this embodiment, a flexible joint 23 is provided at a position behind the direct catalyst 21.
For this reason, the weakness of this flexible joint 23 can be utilized to make it easier for the components of the exhaust system to be deformed downward, and to promote the dive into the tunnel enlarged portion 20 at the time of a vehicle collision.

In this embodiment, a steering rack 16 for steering the front wheels is disposed on the vehicle front side of the direct catalyst 21 (see FIGS. 2 and 5).
As a result, hot air around the direct catalyst 21 is less likely to flow through the steering rack 16 during traveling of the vehicle.
Therefore, the heat damage by the direct catalyst 21 with respect to the steering rack 16 can be suppressed, and the durability of the steering rack 16 can be enhanced.

Further, in this embodiment, the engine 7 is inclined so that the engine upper portion 7a is located on the vehicle rear side (see FIG. 2).
As a result, a space can be secured in front of the engine upper portion 7a and behind the engine lower portion 7b. Further, the position of the exhaust port 11 of the engine 7 can be lowered.
For this reason, the arrangement space of the intake manifold 8 arranged in front of the engine 7 can be expanded. Further, the front differential 13 disposed behind the engine 7 can be disposed on the vehicle front side. Furthermore, since the position of the exhaust port 11 is lowered, the components of the exhaust system can be more easily laid out in a straight line, and the exhaust efficiency of the engine 7 can be increased. In addition, since the distance to the direct catalyst 21 can be shortened, early activation of the catalyst can be achieved.
Therefore, by arranging the engine 7 to be inclined rearward, the performance of the intake / exhaust system of the rear exhaust engine can be improved, and the amount of overhang of the vehicle can be reduced, so that the vehicle's driving performance can also be improved. .

  As another embodiment, a vehicle front structure as shown in FIG. 10 is also conceivable. That is, the components of the exhaust system are configured such that the flexible joint 123 is disposed immediately after the exhaust manifold 9, the collective exhaust pipe 122 is disposed behind the flexible joint 123, and the catalyst 124 is disposed behind the flexible exhaust pipe 122. Of these, the flexible joint 123 is laid out in the tunnel enlarged portion 20.

  As described above, by laying out the flexible joint 23 in the tunnel expanding portion 20, the flexible joint having a large occupied space can be obtained in this embodiment using a relatively large space (internal space S) in the tunnel expanding portion 20. 123 can be easily laid out.

  In particular, since it is provided in front of the Y-shaped exhaust pipe 22, it is necessary to arrange two flexible joints 123 in parallel. However, since the internal space S of the tunnel expansion portion 20 is large, the flexible joint 123 is laid out reliably. be able to.

  Therefore, it is not necessary to install the flexible joint 123 having a large occupied space between the engine 7 and the dash panel 4, and the collision safety can be further improved.

As described above, in the correspondence between the configuration of the present invention and the above-described embodiment,
The intake pipe of the present invention corresponds to the intake manifold 8 and the surge tank 10,
Hereinafter, similarly, the exhaust pipe corresponds to the exhaust manifold 9, the direct catalyst 21, the Y-shaped exhaust pipe 22, the flexible joint 23, and the underfoot catalyst 24,
The steering mechanism corresponds to the steering rack 16,
The present invention is not limited to the above-described embodiment, but includes any vehicle front structure embodiment.
In the present embodiment, a general vehicle including the transmission 12 has been described. However, the present invention may be implemented using a front structure of a hybrid vehicle including a motor / generator.

The perspective view which showed the characteristic part of the front part structure of a vehicle. The whole side view of the front part structure of a vehicle. The whole front view except an engine. The whole top view including a body frame etc. The whole bottom view including the body frame etc. The detailed side sectional view of the tunnel enlarged portion vicinity. The detailed plane sectional view near the tunnel expansion part. It is explanatory drawing which showed the behavior at the time of the vehicle collision in a side view, (a) is the early stage of a collision, (b) is the middle stage of a collision, (c) is the figure which showed the late stage of a collision. It is explanatory drawing which showed the behavior at the time of the vehicle collision in planar view, (a) is the figure which showed the collision early stage, and (b). The whole side view of the front part structure of the vehicle of other embodiments.

Explanation of symbols

ER ... Engine room CR ... Cab 4 ... Dash panel 5 ... Floor panel 7 ... Engine 8 ... Intake manifold 9 ... Exhaust manifold 20 ... Enlarged tunnel part 20a ... Upper wall surface 21 ... Straight catalyst 23 ... Flexible joint 24 ... Underfoot caterer List 124 ... Catalyst

Claims (5)

A vehicle front structure in which an engine is disposed horizontally in an engine room at the front of the vehicle, an intake pipe is disposed in front of the engine, and an exhaust pipe is disposed behind the engine,
The exhaust pipe is formed so as to extend from the exhaust port at the top of the engine to the lower rear side of the vehicle so as to extend substantially linearly at a predetermined inclination angle,
In the vehicle width direction center of the connecting portion between the dash panel and the floor panel constituting the front wall of the passenger compartment, a tunnel portion that protrudes toward the passenger compartment side and extends in the vehicle front-rear direction is formed.
A vehicle front structure in which a tunnel expansion portion is provided at a front portion of the tunnel portion so as to largely protrude upward along the exhaust pipe and includes an upper wall surface inclined so as to correspond to an inclination angle of the exhaust pipe. The vehicle front structure according to claim 1, wherein an exhaust port of the engine is set at a position below an extended line of an inclination angle of an upper wall surface of the tunnel enlarged portion. A catalyst or flexible tube is provided in the middle of the exhaust pipe,
The vehicle front structure according to claim 1 or 2, wherein the catalyst or the flexible tube is disposed at a position corresponding to the tunnel enlarged portion. The vehicle front structure according to claim 3, wherein a steering mechanism for steering front wheels is disposed on the vehicle front side of the catalyst. The front part structure of the vehicle according to claim 1, wherein the engine is inclined so that an upper part of the engine is located on a vehicle rear side.

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