Fuel routing structure for a V-type engine

The present application claims priority under 35 USC 119 based on Japanese patent application No. 2004-246196, filed Aug. 26, 2004. The subject matter of this priority document is incorporated by reference herein.

1. Field of the Invention

The present invention relates to a fuel and air routing structure for a V-type engine in a vehicle, the engine including cylinder heads provided in longitudinally arranged V-shaped banks. The fuel routing structure includes a member forming an intake passage communicating with intake ports of cylinder heads arranged between the pair of banks. Fuel injection valves for injecting fuel into the intake passage corresponding to each intake port are attached to the intake manifold.

2. Description of the Background Art

The fuel routing structure of a V-type engine for a vehicle in which fuel injection valves corresponding to each cylinder in cylinder heads of both banks are attached to an intake manifold common to a pair of banks and arranged between both banks is already known. An example of such a fuel routing structure is disclosed, for example, in JP-A No. 204969/2000.

However, in the above-mentioned conventional type fuel routing structure, both a fuel rail connected to the fuel injection valve corresponding to one bank and a fuel rail connected to the fuel injection valve corresponding to the other bank are required. Thus, a large number of parts are required for the structure, the fuel routing structure is intricate, and in addition, assembly and maintenance of the structure is troublesome.

The present invention is made in view of such a situation and the object is to provide fuel supply equipment of a V-type engine for a vehicle where fuel is supplied to each fuel injection valve by a structure in which the number of parts is reduced, which is compact and in addition, operability in assembly and in maintenance is enhanced.

To achieve the object, a first aspect of the invention is based upon a fuel routing structure of a V-type engine for a vehicle. The fuel routing structure includes a member forming an intake passage that communicates with intake ports of cylinder heads of the engine. In the engine, a pair of cylinder banks are provided forming a V shape and arranged longitudinally with respect to the vehicle. The intake manifold is arranged between the pair of banks. Fuel injection valves are attached to the intake manifold for injecting fuel into the intake passage corresponding to each intake port. The first aspect of the invention is characterized in that each fuel injection valve is attached to an upper part of the intake manifold so that center lines of the fuel injection valves corresponding to both banks are crossed at an intersection over the intake manifold when the vehicle is viewed from the side. In addition, a fuel rail provided with a fuel passage pipe, the axis of which is arranged in the vicinity of the intersection and which is parallel to a crankshaft and which is extended linearly, is connected to all the fuel injection valves in common and is directly attached to the intake manifold.

A second aspect of the invention, in addition to configuration in first aspect, is characterized in that the intake passage is configured by branched passages individually communicating with the intake ports. A common passage communicates with the branched passages in common, and the axis of the common passage is arranged in parallel with the axis of the fuel passage pipe.

The third aspect of the invention, in addition to configuration described with respect to the first or second aspects, is characterized in that a fuel inlet to which a fuel hose is to be connected is formed at one end of the fuel passage pipe so that the fuel inlet is open to one side of the vehicle.

Further, the fourth aspect of the invention, in addition to the configuration of the third aspect, is characterized in that the fuel rail is integrally provided with the fuel passage pipe. One end of the fuel passage pipe is a fuel inlet and the other end is closed. Plural fluid-tight valve connections connect the rear of each fuel injection valve to the fuel passage pipe.

According to the first aspect of the invention, since fuel is supplied to each fuel injection valve using the fuel rail, fewer parts are required and the fuel routing structure is made compact. That is, by connecting the single fuel rail common to the fuel injection valves to the fuel injection valves individually corresponding to the intake ports of the cylinder heads of both banks, and because the fuel rail is connected to each fuel injection valve over the intake manifold, operability in assembly and in maintenance is enhanced. In addition, because the fuel rail is directly attached to the intake manifold, a dedicated member for supporting the fuel rail is not required and the number of parts is further reduced.

According to the second aspect of the invention, the attachment and the detachment of the fuel rail to/from the intake manifold are facilitated and operability in assembly and in maintenance is further enhanced.

According to the third aspect of the invention, not only is the connection structure of the fuel hose to the fuel rail facilitated but work for connecting the fuel hose to the fuel rail can be facilitated.

Further, according to the fourth aspect of the invention, as fuel is not returned from the fuel rail, a return pipe is not required and the fuel routing structure is simplified and small in size.

For a more complete understanding of the present invention, the reader is referred to the following detailed description section, which should be read in conjunction with the accompanying drawings. Throughout the following detailed description and in the drawings, like numbers refer to like parts.

FIG. 1 is a side elevational view of a motorcycle including a V-type engine, which incorporates a fuel and air routing structure according to a first selected illustrative embodiment of the present invention;

FIG. 2 is a side plan view, partly in cross-section, of a main part of the V-type engine of the motorcycle depicted in FIG. 1 , showing the intake manifold positioned between the front and rear cylinder banks;

FIG. 3 is a top plan view of the V-type engine of FIGS. 1–2 as seen in a direction shown by an arrow 3 in FIG. 2 ;

FIG. 4 is an enlarged top plan detail view of the fuel routing structure according to the first embodiment, showing the intake manifold and a fuel rail;

FIG. 5 is side plan view of the intake manifold and fuel routing structure of FIG. 4 ;

FIG. 6 is an enlarged top plan detail view of a fuel routing structure according to a second embodiment, showing an intake manifold and a fuel rail;

FIG. 7 is side plan view of the fuel routing structure of FIG. 6 , as viewed in a direction shown by an arrow 7 in FIG. 6 ; and

FIG. 8 is a side plan view, partly in cross-section and showing a main part of a V-type engine incorporating an fuel routing structure according to a third embodiment of the present invention.

Referring to the attached drawings, a number of selected illustrative embodiments of the present invention will be described below. It should be understood that only structures considered necessary for clarifying the present invention are described herein. Other conventional structures, and those of ancillary and auxiliary components of the system, are assumed to be known and understood by those skilled in the art.

FIGS. 1 to 5 show a fuel and air routing structure according to a first embodiment of the invention, FIGS. 6 and 7 show a fuel and air routing structure according to a second embodiment, and FIG. 8 shows a fuel and air routing structure according to a third embodiment.

A motorcycle 100 having a body frame F, with a V-type engine E mounted transversely thereon, is shown in side elevational view in FIG. 1 . The engine E of the motorcycle incorporates an intake manifold 31 therein for routing fuel and air, according to a first embodiment of the present invention, as will be described in some detail herein. The motorcycle 100 includes a front fork 6 for rotatably supporting a front wheel WF at a terminal end thereof. The front fork 6 is pivotally supported by a head pipe 5 which is provided at the front end of the body frame F of the motorcycle 100 , so that the front fork can be steered. A steering handlebar 7 is coupled to the upper end of the front fork 6 . A power unit P includes an engine E and a transmission M housed in a crankcase 8 of the engine E. The power unit P is mounted in the front inside the body frame F. A fuel tank 9 is mounted in the front inside the body frame F so that the fuel tank covers the upper side of the engine E.

Each front end of a pair of right and left swing arms 10 extends longitudinally and is supported by the body frame F on the rear side of the power unit P so that each front end can be vertically rocked. A rear wheel WR is supported between the rear ends of both swing arms 10 . A rear shock absorber 11 is inserted between the body frame F and the rear end of each swing arm 10 . In addition, the left swing arm 10 of both swing arms 10 is formed cylindrically and a drive shaft 12 for transmitting motive power from the power unit P to the rear wheel WR is housed in the left swing arm 10 .

A main seat 13 for seating a rider is attached to the body frame F on the rear side of the fuel tank 9 , and a pillion seat 14 is attached to the body frame F on the rear side of the main seat 13 .

A front fender 15 , covering the front wheel WF from above, is attached to the front fork 6 , and a rear fender 16 , covering the rear wheel WR from above, is attached to the rear of the body frame F.

Also referring to FIG. 2 , the body 17 of a transversely mounted V-type two-cylinder engine E is provided with a crankcase 8 supporting a crankshaft 18 . As used herein, the term “transversely mounted”, as used to describe the engine E, means that the engine is situated on the body frame F in a manner such that a central axis of the crankshaft 18 is oriented substantially transverse to a longitudinal axis of the body frame. The crankshaft 18 has an axis that extends in a cross direction (that is, from the left side of the vehicle to the right side, as viewed in the forward driving direction) of the body frame F. The engine E includes a pair of front and rear cylinder blocks 20 F, 20 R arranged in a V shape open upwardly and connected to the crankcase 8 . The engine E also includes a respective cylinder head 21 F, 21 R connected to each cylinder block 20 F, 20 R, and a respective head cover 22 F, 22 R connected to the upper end of each cylinder head 21 F, 21 R. The engine E further includes a front bank BF formed by the cylinder block 20 F, the cylinder head 21 F and the head cover 22 F, and a rear bank BR formed by the cylinder block 20 R, the cylinder head 21 R and the head cover 22 R. The front and rear banks BF, BR cooperate to form the V-type engine, with the banks oriented at a small angle α, of approximately 52° for example.

Pistons 23 F, 23 R are fitted into the cylinder blocks 20 F, 20 R so that the pistons can slide therein. Combustion chambers 24 F, 24 R which receive the tops of pistons 23 F, 23 R are formed between the cylinder block 20 F and the cylinder head 21 F in the front bank BF, and between the cylinder block 20 R and the cylinder head 21 R in the rear bank BR. Intake ports 25 F, 25 R that can communicate with the combustion chambers 24 F, 24 R are open on each inner wall of the cylinder heads 21 F, 21 R. Exhaust ports 26 F, 26 R that can communicate with the combustion chambers 24 F, 24 R are open on each outer wall of the cylinder heads 21 F, 21 R. In addition, each pair of intake valves 27 F, 27 R for controlling the communication and the cutoff with/from the combustion chambers 24 F, 24 R of the intake ports 25 F, 25 R are arranged in the cylinder heads 21 F, 21 R so that so that each pair can be opened or closed together. Similarly, each pair of exhaust valves 28 F, 28 R for controlling the communication and the cutoff with/from the combustion chambers 24 F, 24 R of the exhaust ports 26 F, 26 R are arranged in the cylinder heads 21 F, 21 R so that each pair can be opened or closed together.

Each valve chamber 30 F, 30 R houses each valve train 29 F, 29 R for opening or closing each pair of intake valves 27 F, 27 R and each pair of exhaust valves 28 F, 28 R. The valve chamber 30 F, 30 R is formed between each cylinder head 21 F, 21 R and each head cover 22 F, 22 R in the front and rear banks BF, BR.

Further, an intake manifold 31 is connected to both cylinder heads 21 F, 21 R via the intake ports 25 F, 25 R of the cylinder heads 21 F, 21 R with which the banks BF, BR are provided. The intake manifold 31 is arranged between the front and rear banks BF, BR.

Also referring to FIGS. 3 to 5 , the intake manifold 31 has an intake passage 34 formed therein, and includes branched passages 32 F, 32 R individually communicating with the intake ports 25 F, 25 R of each bank BF, BR. The intake manifold 31 also includes a common passage 33 communicating with both of the branched passages 32 F, 32 R, and extending in parallel with the axis of the crankshaft 18 . The intake manifold 31 is fastened to the cylinder heads 21 F, 21 R of the front and rear banks BF, BR by each pair of bolts 46 , 46 ( FIG. 3 ).

An air cleaner 35 is connected to the intake manifold 31 via a throttle body 41 and a connecting hose 42 , in this order from the upstream side, so that the air cleaner communicates with the common passage 33 . An intake duct 43 for leading outside air into the air cleaner 35 is arranged on the side of the front bank BF in a state in which the intake duct is open upward under the fuel tank 9 . A sensor unit 44 including a throttle position sensor, an intake pressure sensor, an intake air temperature sensor and an idle control valve 45 are provided on the throttle body 41 .

Fuel injection valves 36 F, 36 R inject fuel individually into the branched passages 32 F, 32 R and are attached to the intake manifold 31 corresponding to both banks BF, BR. Both fuel injection valves 36 F, 36 R are attached to an upper part of the intake manifold 31 so that center lines CF, CR of the fuel injection valves 36 F, 36 R are crossed at an intersection P, over the intake manifold 31 , when the body is viewed from the side. In addition, a fuel rail 37 is provided with a fuel passage pipe 37 a , the axis of which is arranged at the intersection P. The fuel rail 37 is parallel to the crankshaft 18 , is linearly extended, and is connected to both fuel injection valves 36 F, 36 R in common.

The fuel rail 37 is integrally provided with the fuel passage pipe 37 a and a pair of valve connections 37 b , 37 c fitted to the rear of each fuel injection valve 36 F, 36 R, in a fluid-tight manner, so that each fuel injection valve 36 F, 36 R communicates with the fuel passage pipe 37 a . The fuel rail 37 is also integrally provided with mounting parts 37 d , 37 e directly mounted on the upper surface of the intake manifold 31 by bolts 38 , 38 , and the fuel rail 37 is directly mounted on the upper part of the intake manifold 31 .

In addition, a fuel inlet 40 is formed at one end of the fuel passage pipe 37 a in the fuel rail 37 so that the fuel inlet is open toward one side, that is a lateral side, of the vehicle body. The fuel inlet 40 is connected to a fuel hose 39 via a quick connector 47 . The other end of the fuel passage pipe 37 a is closed, and the fuel rail 37 is configured as a deadheaded, returnless structure, in which the return of fuel is disabled.

Next, the action of the fuel routing structure according to the first embodiment hereof will be described. Each fuel injection valve 36 F, 36 R is attached to the upper part of the intake manifold 31 so that the center lines CF, CR of the fuel injection valves 36 F, 36 R corresponding to the front and rear banks BF, BR of the V-type two-cylinder engine E are crossed at the intersection P over the intake manifold 31 , when the vehicle is viewed from the side. The fuel rail 37 , provided with the fuel passage pipe 37 a , the axis of which is arranged at the intersection P, which is parallel to the crankshaft 18 and which is linearly extended, is connected to all the fuel injection valves 36 F, 36 R in common. As seen in the top view of FIG. 4 , the fuel injection valves 36 F, 36 R are spaced laterally apart along the fuel rail 37 , in a vehicle width direction. Because the fuel injection valves 36 F, 36 R are spaced laterally apart along the fuel rail, upper end portions of the fuel injection valves are permitted to overlap one another when viewed from a lateral side of the vehicle, as seen in FIG. 5 . As a result, fuel is supplied to each fuel injection valve 36 F, 36 R using the fuel rail 37 such that the number of parts are reduced and the fuel rail 37 is made compact by connecting the single fuel rail 37 to both of the fuel injection valves 36 F, 36 R corresponding to both banks BF, BR. In addition, since the fuel rail 37 is connected to each fuel injection valve 36 F, 36 R over the intake manifold 31 , ease of assembly and in maintenance can be enhanced.

Because the fuel rail 37 is directly attached to the intake manifold 31 , a separate dedicated member for supporting the fuel rail 37 is not required, and the number of parts is further reduced.

In addition, the intake passage 34 formed in the intake manifold 31 is configured by the branched passages 32 F, 32 R individually communicating with the intake ports 25 F, 25 R and the common passage 33 communicating with both branched passages 32 F, 32 R. The axis of the common passage 33 is arranged in parallel with the axis of the fuel passage pipe 37 a with which the fuel rail 37 is provided. As a result, the attachment and the detachment of the fuel rail 37 to/from the intake manifold 31 are facilitated, and operability in assembly and in maintenance is further enhanced.

The fuel inlet 40 to which the fuel hose 39 is to be connected is open toward one side of the vehicle and is formed at one end of the fuel passage pipe 37 a . As a result, not only the connection structure to the fuel rail 37 of the fuel hose 39 is facilitated, but work for connecting the fuel hose 39 to the fuel rail 37 is also facilitated.

Further, the fuel rail 37 is integrally provided with the fuel passage pipe 37 a , one end of which is the fuel inlet 40 , and the other of which is closed. The fuel rail is also provided with the plural valve connections 37 b , 37 c , which connect each fuel injection valve 36 F, 36 R to the fuel passage pipe 37 a , and to which the rear of each fuel injection valve 36 F, 36 R is fitted in a fluid-tight manner. Moreover, the fuel rail 37 is configured as a deadheaded, returnless structure in which the return of fuel is disabled. As a result, a return pipe is not required by eliminating the return of fuel from the fuel rail 37 , and the resulting fuel routing structure is simplified and compact.

FIGS. 6 and 7 show a second embodiment of the invention. In the figures and following description of this embodiment, the same reference numeral is allocated to the similar component to that in the first embodiment, and the detailed description is omitted.

An intake manifold 31 ′ forms an intake passage 34 configured by branched passages 32 F, 32 R individually communicating with intake ports 25 F, 25 R (refer to the first embodiment shown in FIGS. 1 to 5 ) of each bank BF, BR, and a common passage 33 which communicates with both of the branched passages 32 F, 32 R, and which extends in parallel with the axis of a crankshaft 18 (refer to the first embodiment shown in FIGS. 1 to 5 ). Fuel injection valves 36 F, 36 R for individually injecting fuel into each branched passage 32 F, 32 R are attached to the intake manifold 31 ′.

In addition, both fuel injection valves 36 F, 36 R are attached to an upper part of the intake manifold 31 ′ so that center lines CF, CR of the fuel injection valves 36 F, 36 R are crossed at an intersection P over the intake manifold 31 ′ when a vehicle is viewed from the side. A fuel rail 37 ′ is provided with a fuel passage pipe 37 a . The axis of fuel passage pipe 37 a is arranged at the intersection P, is parallel to the crankshaft 18 and is linearly extended. The fuel passage pipe 37 a is connected to both fuel injection valves 36 F, 36 R in common.

The fuel rail 37 ′ is integrally provided with the fuel passage pipe 37 a , a pair of valve connections 37 b , 37 c which connect each fuel injection valve 36 F, 36 R to the fuel passage pipe 37 a and to which the rear of each fuel injection valve 36 F, 36 R is fitted in a fluid-tight manner. The fuel rail 37 ′ is also integrally provided with mounting parts 37 d , 37 e which are directly attached to an upper surface of the intake manifold 31 ′ by bolts 38 , 38 , and is directly attached to the upper part of the intake manifold 31 ′.

In this embodiment, the common passage 33 in the intake passage 34 is formed so that its axis is located off the axis of the fuel passage pipe 37 a toward the rear of the vehicle, as clearly shown in FIG. 7 .

Further, a fuel inlet 40 is formed at one end of the fuel passage pipe 37 a in the fuel rail 37 , so that the fuel inlet is open to one lateral side of the vehicle and is connected to a fuel hose 39 via a quick connector 47 . The other end of the fuel passage pipe 37 a is closed, and the fuel rail 37 is configured as a deadheaded, returnless structure in which the return of fuel is disabled.

According to the second embodiment, in addition to an advantage that the similar effect to that of the first embodiment can be produced, the amount of freedom in the layout of the intake passage 34 is increased. In addition, the intake manifold 31 ′ and a throttle body 41 (see FIG. 3 in the first embodiment) ranging to the intake passage 34 can be arranged, avoiding interference with the cylinder heads 21 F, 21 R of both banks BF, BR.

Even if the common passage 33 in the intake passage 34 is formed so that the axis is arranged in a position off the axis of the fuel passage pipe 37 a toward the rear of the vehicle differently from FIG. 7 , the similar effect can be acquired.

FIG. 8 shows a third embodiment of the invention. In the figures and following description of this embodiment, the same reference numeral is allocated to the similar component to that in the first and second embodiments, and the detailed description is omitted.

The body 17 ′ of a V-type two-cylinder engine E′ is provided with a crankcase 8 ′ supporting a crankshaft 18 ′ so that the crankshaft can be rotated. A pair of front and rear cylinder blocks 20 F′, 20 R′ are arranged in a V-shape opening upwardly, and are connected to the crankcase 8 ′. Cylinder heads 21 F′, 21 R′ are connected to each cylinder block 20 F′, 20 R′ and head covers 22 F′, 22 R′ are connected to the upper ends of the cylinder heads 21 F′, 21 R′. A front bank BF′ is configured by the cylinder block 20 F′, the cylinder head 21 F′ and the head cover 22 F′, and a rear bank BR′ is configured by the cylinder block 20 R′, the cylinder head 21 R′ and the head cover 22 R′ to form a V type at a small angle a of approximately 52° for example, and are coupled to the crankcase 8 ′.

An intake manifold 51 , connected to both cylinder heads 21 F′, 21 R′, is arranged between the front and rear banks BF′, BR′ so that the intake manifold 51 communicates with intake ports 25 F′, 25 R′ of the cylinder heads 21 F′, 21 R′ with which the banks BF′, BR′ are provided.

The intake manifold 51 has an intake passage 54 formed therein, configured by branched passages 52 F, 52 R individually communicating with the intake ports 25 F′, 25 R′ of each bank BF′, BR′. The intake manifold 51 also includes a common passage 53 communicating with both of the branched passages 52 F, 52 R, and extended in parallel with the axis of the crankshaft 18 ′. The intake manifold 51 is connected to the cylinder heads 21 F′, 21 R′ of the front and rear banks BF′, BR′ via insulators 55 F, 55 R.

Fuel injection valves 36 F, 36 R for injecting fuel to each branched passage 52 F, 52 R are attached to the intake manifold 51 corresponding to both banks BF′, BR′. Both fuel injection valves 36 F, 36 R are fitted and attached to an upper part of the intake manifold 51 in a fluid-tight manner, so that center lines CF, CR of the fuel injection valves 36 F, 36 R are crossed at an intersection P over the intake manifold 51 when a vehicle is viewed from the side.

A fuel rail 57 is provided with a fuel passage pipe 57 a . The axis of fuel passage pipe 57 a is arranged in the vicinity of the intersection P, is parallel to the crankshaft 18 ′ and extends linearly. The fuel passage pipe 57 a is directly attached to the upper part of the intake manifold 51 , and the fuel rail 57 is arranged so that the axis of the fuel passage pipe 57 a is located in a position off the axis of the common passage 53 in the intake passage 54 toward the rear of the vehicle and in a position off the axis of the crankshaft 18 ′ toward the front of the vehicle.

Valve connections 57 b , 57 c with which the fuel rail 57 is provided are fitted to the rears of both fuel injection valves 36 F, 36 R in a fluid-tight manner. A fuel hose 39 (refer to the first and second embodiments) is connected to one end of the fuel passage pipe 57 a , and the other end of the fuel passage pipe 57 a is closed.

According to the third embodiment, the amount of freedom in the layout of the fuel rail 57 can be increased, and the fuel rail 57 can be arranged without interfering with a fuel tank 9 (see FIG. 1 in the first embodiment) arranged over the engine E′ or the other vehicle components.

Although the present invention has been described herein with respect to a limited number of presently preferred embodiments, the foregoing description is intended to be illustrative, and not restrictive. Those skilled in the art will realize that many modifications of the preferred embodiment could be made which would be operable. All such modifications, which are within the scope of the claims, are intended to be within the scope and spirit of the present invention.