Vehicle fuel supply device and fuel filter structure

Descriptive Report of the Invention Patent for a MOTORCYCLE EQUIPPED WITH AN ENGINE CAPABLE OF OPERATING WITH VARIOUS DIFFERENT TYPES OF FUELS.

DESCRIPTION

TECHNICAL AREA

The present invention relates to an improvement in fuel dispensing devices for vehicles, as well as an improvement in fuel filter structures, which contain a fuel filter made of non-woven material.

BACKGROUND OF THE TECHNIQUE

Among the conventionally known vehicle fuel dispensing devices are those that include a fuel filter inside a fuel tank (e.g., International Publication WO2004/072469). In the vehicle fuel dispensing device described in Patent Literature 1, the fuel filter is located substantially centrally at the bottom of the fuel tank, a fuel pump unit is located at the rear of the fuel tank, and the fuel filter and fuel pump unit are interconnected by a fuel line.

In cases where fuel, such as ethanol, containing fine dust is used, the fuel filter must have a small filtration mesh or pore size (i.e., filtration fineness); however, in these cases, the fuel filter must be replaced in a short cycle, which increases the number of times maintenance service must be performed. Furthermore, when this small-pore fuel filter is located upstream of the fuel pump unit, and when the amount of fuel to be dispensed increases rapidly, for example, during vehicle acceleration, it is difficult for the required amount of fuel to be dispensed because the fuel filter becomes a resistance to the fuel flow. The need arises to increase the capacity or output of the fuel pump unit, which requires higher costs.

Furthermore, fuel supply devices have been known in which a filter housing and a pressure regulator are provided in one piece with each other (for example, Japanese Patent Application Publication No. 08-74710 (JP-08-74710 A)). In the fuel dispensing device described in Patent Literature 2, a fuel filter includes: a housing with an inlet, an outlet, and a recirculation opening; a filter insert piece with a cylindrical shape, disposed within the housing; and a pressure regulator, disposed within the housing, adjacent to the recirculation opening. The filter insert piece has opposing end caps, installed in the housing and supported by a support tube. The pressure regulator is located inside the filter insert, and the fuel is filtered as it passes through the filter insert from the outside to the inside of the filter insert.

If an attempt is made to ensure a large surface area of ​​the filter insert for greater filtration capacity, the housing needs to be larger. Furthermore, since the filter insert requires the support tube acting as a frame, and end caps, the fuel dispensing device needs a large number of component parts and thus requires high costs. Furthermore, the pressure regulator inside the housing is subject to spatial limitations due to the placement of the filter insert and support tube, resulting in extremely limited freedom of arrangement for the pressure regulator, fuel suction opening, etc. Additionally, if the pressure regulator is placed near the recirculation opening, the location for installing the recirculation opening will be limited.

Furthermore, fuel filter structures have been known that contain a filter element made of non-woven material or similar (e.g., Japanese Patent Application Publication No. 2003-148267 (JP 2003-148267 A)). In the fuel dispensing device described in JP 2003-148267 A, a filter cartridge includes a bag-shaped filter element, formed of a mesh, nonwoven material or similar, and a mounting section, provided in one piece with the bag-shaped filter element. The connection opening, provided in the mounting section, is connected to a suction opening of a fuel pump. The bag-shaped filter element is attached to the mounting section by means of a suction opening member inserted into the element. The suction opening member has, in one piece, a frame member, to retain the bag-shaped filter element in an inflated format.

In cases where a primary fuel filter with a small pore size is used in a fuel system, such as that described in document JP 2003-14827 A, to filter fuel, such as ethanol fuel, containing fine dust (particles), clogging can easily occur in the primary fuel filter. If the surface area of ​​the primary fuel filter is increased in order to extend the life of the primary fuel filter, the primary fuel filter will increase in size, resulting in limited design freedom and higher costs. Furthermore, since the aforementioned filter cartridge includes the suction opening member, the mounting section, and the frame member, in addition to the pouch-shaped element, the cartridge would have to be quite large overall. With vehicles, such as motorcycles, where there is a considerable limitation regarding the available space in the vehicle body, it is desirable to build the fuel supply system in a compact size, using a non-woven material filter, which achieves high filtration efficiency even with a small surface area.

DESCRIPTION OF THE INVENTION

In view of the foregoing, it is an object of the present invention to make available a fuel supply device for vehicles that is inexpensive, achieves a prolonged cycle between fuel filter changes or replacements, and can consistently supply a necessary amount of fuel.

Another objective of the present invention is to provide an improved fuel supply device, equipped with a fuel filter, which is compact in size and requires only a small number of component parts and which can increase the freedom of arrangement of a pressure regulator, fuel suction opening, etc.

And yet another objective of the present invention is to provide an improved fuel filter structure which allows for a prolonged fuel filter life, and which achieves a reduced fuel filter size by housing the filter compactly in a housing.

According to one aspect of the present invention, an improved vehicle fuel supply device is made available, comprising: a fuel pump, for supplying fuel from a fuel tank to an injector, which propels the fuel towards an engine; a primary fuel filter, disposed in a fuel passage upstream of the fuel pump; and a secondary fuel filter, located in the fuel passage downstream of the fuel pump. The secondary fuel filter has a smaller filtration mesh or pore size than the primary fuel filter, and the secondary fuel filter is covered with a housing member and arranged along a vehicle body chassis.

In conventionally known fuel dispensing devices, where only one fuel filter is provided, both large (particular) and fine (particular) dust are collected by the same filter, so the fuel filter tends to become easily clogged, thus making the fuel filter replacement cycle very short. Furthermore, the amount of fuel passing through the fuel filter tends to be small. In the fuel dispensing device of the present invention, on the other hand, the pore size of the secondary fuel filter is smaller than that of the primary fuel filter; thus, large (particle) dust is collected by the primary fuel filter, and then finer (particle) dust, which has passed through the primary fuel filter, is collected by the secondary fuel filter. Since this arrangement according to the invention effectively prevents the secondary fuel filter from collecting large dust particles, the secondary fuel filter may be less susceptible to clogging, and thus the frequency of replacement of the secondary fuel filter may be reduced. Furthermore, the primary fuel filter may also be less susceptible to clogging due to its large pore size, and thus may be prevented from becoming a resistance to the fuel flow in the fuel pump.

Consequently, a high flow rate of fuel passing through the primary fuel filter and secondary fuel filter can be safely maintained over a long period of time. Therefore, a fairly inexpensive fuel pump can be used in the fuel dispensing device of the invention. As a result, the present invention can achieve longer exchange or replacement cycles for both the primary and secondary fuel filters, so that the number of times maintenance work needs to be performed can be reduced. Furthermore, a high fuel flow rate passing through the primary fuel filter and the secondary fuel filter can be maintained over a long period of time, and thus the present invention can appropriately handle situations where the fuel flow rate increases rapidly.

Preferably, the secondary fuel filter is located at the rear of the engine. With this arrangement, the fuel dispensing device of the invention can make the second fuel filter less susceptible to engine heat, as compared to conventionally known fuel dispensing devices where the fuel filter is located above the engine.

Ideally, the secondary fuel filter is positioned laterally outside the chassis body. This way, maintenance work, such as replacing the secondary fuel filter, can be easily performed from one side of the vehicle.

Ideally, the secondary fuel filter is attached to the body chassis by means of a bracket, and the body chassis has an inwardly concave part, formed in a position corresponding to an inner surface of the secondary fuel filter. Thus, when an external lateral force acts on the secondary fuel filter, for example, the support is bent towards the interior of the vehicle body, and the secondary fuel filter moves into the concave part within the chassis of the vehicle body; In this way, the mobile capacity of the secondary fuel filter can be increased, and the increased mobile capacity allows an external force acting on the secondary fuel filter to be absorbed with increasing ease.

Ideally, the secondary fuel filter is covered on one of its outer side surfaces with an external member. In this way, the outer side surface is not exposed to the outside, so that an enhanced external appearance of the vehicle can be obtained.

Ideally, a fuel supply line is connected to a downstream side of the secondary fuel filter and extends upward to a throttle valve body located above the secondary fuel filter. In this way, air inside the secondary fuel filter can easily flow into the fuel injector valve of the throttle valve body through the fuel supply line. This arrangement allows for a uniform supply of fuel through the fuel passage, including the secondary fuel filter.

Preferably, the fuel dispensing device has a fuel return opening provided in an upper part of the housing member, and a fuel return tube arranged to extend upwards from the fuel return opening to the fuel tank. In this way, if air is mixed into the fuel line from the fuel pump, the air can easily be forced out of the fuel line.

According to another aspect of the present invention, an improved fuel dispensing device is made available, comprising: a fuel filter, disposed outside a fuel tank; and a filter housing, which covers an outer surface of the fuel filter; It has a pressure regulator, housed as a part within the filter housing, to regulate the pressure inside the fuel filter. The fuel that has passed through the pressure regulator is then returned to the fuel tank. The fuel filter is shaped like a bag, and the fuel is filtered as it passes through the fuel filter from the inside to the outside.

Because the fuel filter is bag-shaped, it can be housed compactly within the filter housing, and the housing can be formed into a reduced size. Furthermore, since the fuel filter body is inflated and held stably in its inflated shape when fuel is passed through the bag-shaped fuel filter from the inside to the outside, no special frame members are required for the fuel filter. As a result, the present invention can reduce the number of component parts required for the fuel filter.

Furthermore, since the fuel filter to be housed within the housing can be easily changed in shape as needed, the present invention can increase the freedom of arrangement of the pressure regulator and fuel return opening, provided near the pressure regulator.

Ideally, the fuel filter is located downstream of a fuel pump, and the pressure regulator is located downstream of the fuel filter. In this way, the fuel that has passed through the fuel filter body is returned to the fuel tank, via the pressure regulator, with most of the dust removed or filtered from the fuel. Consequently, if another filter, for example, a primary fuel filter, is provided inside the fuel pump, the amount of dust to be filtered through the primary fuel filter can be significantly reduced. As a result, the present invention can achieve a longer replacement cycle of the primary fuel filter, so that the number of times maintenance work must be performed can be reduced.

Preferably, the fuel supply device also comprises a fuel return pipe, arranged to extend upwards from the pressure regulator to the fuel tank, located above the pressure regulator. In this way, air accumulated inside the fuel filter can easily escape, through the pressure regulator, to the fuel tank, located above the fuel filter. As a result, the present invention makes it possible for fuel to be supplied uniformly through the fuel passage.

Preferably, the fuel dispensing device further comprises a fuel dispensing pipe for supplying fuel from the fuel tank to the fuel filter, and the fuel dispensing pipe and the fuel return pipe differ from each other in length and outside diameter.

Because the fuel supply pipe and the fuel return pipe have different lengths and outer diameters or widths, these fuel supply pipes and the fuel return pipe are easily distinguishable. Therefore, the present invention can prevent an assembly error when assembling the fuel supply pipe and the fuel return pipe in the fuel filter.

Preferably, the filter housing includes a housing body and a housing cover. The fuel suction opening and the fuel return opening are arranged offset from the central axis of the housing cover; thus, if the pressure regulator is arranged close to the fuel return opening, the present invention can increase the freedom of arrangement and shape of the pressure regulator, which can make the filter housing compact in size.

Preferably, the filter housing has a stepped section that projects radially from the filter housing, and the pressure regulator has a lower end supported on the stepped section. In this way, the present invention can simplify the structure for supporting the pressure regulator, with the result that the increased costs of the filter housing and fuel filter can be minimized.

According to yet another aspect of the present invention, an improved fuel filter structure is provided, comprising a primary fuel filter, disposed upstream of a fuel pump, and a secondary fuel filter, disposed downstream of the fuel pump and made of a non-woven material, having a pore size smaller than the pore size of the primary fuel filter.

Because the secondary fuel filter, made of non-woven material, has a smaller pore size than the primary fuel filter, the primary fuel filter can have a larger pore size, and the life of the primary fuel filter can be extended even further. Since the primary fuel filter is located upstream of the fuel pump, the life of the fuel pump can also be extended if the primary fuel filter is adjusted to a relatively large pore size such that it does not adversely affect the fuel pump. Furthermore, because the secondary fuel filter is made of non-woven material, the effective filtration area can be increased, thus significantly improving filtration efficiency. Additionally, the secondary fuel filter can have a reduced surface area, allowing for compact construction. Furthermore, since fuel filtration is carried out in cooperation by the primary fuel filter and the secondary fuel filter, the present invention can significantly extend the life of the secondary fuel filter, compared to the case where only one of these fuel filters is provided.

According to yet another aspect of the present invention, an improved fuel filter structure is made available, comprising: a housing; and a filter made of non-woven material, the filter being housed in the housing in a rolled or folded form. With the filter housed compactly in the housing in a rolled or folded configuration, with a reduced overall size, the housing and therefore the fuel filter can be smaller in size.

Ideally, it has a bag-like shape, and the filter filters the fuel by passing the fuel through it, from the inside of the filter to the outside. As fuel is supplied to the bag-shaped filter, the filter inflates, so that the dust contained within the filter runs through the filter to the outside due to the increase in internal pressure within the filter, during which dust mixed in the fuel is removed or filtered from the fuel. Since the filter is inflated and maintained in the inflated shape, no special frame member is required to maintain the inflated shape; thus, the present invention can reduce the cost required for the fuel filter and may even further reduce the size of the filter.

Ideally, an inlet opening for the filter is attached to the inner surface of the rolled or folded filter in an outward-facing orientation. This way, no projecting part is formed on the outer wall of the rolled or cylindrically folded part of the filter, allowing for a reduction in housing size. Furthermore, since the internal space of the housing can be efficiently utilized in the manner described above, the filter body can have a larger area.

Ideally, the housing has a plurality of convex parts that project into the inner surface, and the filter is supported, in part, by the convex parts. In this way, when the fuel flows into the filter, the convex parts can provide intermediate spaces between the inflated filter and the inner surface of the housing, and the fuel is allowed to flow through the filter into these intermediate spaces. Consequently, the present invention can suppress a decrease in fuel stream flow, or fuel stagnation, and thus increase fuel filtration efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

Certain preferred embodiments of the present invention are described in detail below, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a side view of a vehicle equipped with a fuel filtration device according to an embodiment of the present invention;

Figure 2 is a side view, showing the main sections of the fuel dispensing device according to the embodiment of the invention;

Figure 3 is a perspective view, showing the main sections of the fuel dispensing device according to the embodiment of the invention;

Figure 4 is a cross-sectional view of a fuel pump used in the fuel dispensing device according to the embodiment of the invention;

Figures 5A and 5B are, in each case, the side and perspective views, illustrating a secondary fuel filter and the mounting structure for it in the embodiment of the invention;

Figures 6A and 6B are plan views, showing the general operation of the mounting structure for the secondary fuel filter;

Figure 7 is a cross-sectional view of the secondary fuel filter;

Figures 8A and 8B are, in each case, a perspective view and a fragmented, exploded view of the secondary fuel filter;

Figures 9A and 9B are explanatory views of a filter element used in the present invention, wherein Figure 9A is a cross-sectional view taken along line 9-9 of Figure 8B, and Figure 9B is a perspective view showing the filter element housed in a filter housing; and

Figures 10A and 10B show a cross-sectional view of the secondary fuel filter according to the present embodiment of the invention. BEST MODE FOR CARRYING OUT THE INVENTION

Initially, reference is made to Figure 1, which shows in side projection a vehicle equipped with a fuel filtration device and a fuel filter structure according to an embodiment of the present invention. Vehicle 10 is a motorcycle, which includes an engine 12, substantially centrally arranged in a vehicle body chassis 11, a front fork 13, steerably supported on a front terminal part of the vehicle body chassis 11, and a rear fork 14, vertically rotating on a lower rear part of the vehicle body chassis 11. Vehicle 10 uses as its main fuel ethanol, gasoline, or a mixture of gasoline and ethanol. and uses gasoline or a mixture of gasoline and ethanol (with a higher gasoline-to-ethanol mixing ratio than in the main fuel) as its subsidiary fuel, only at the moment of engine start-up, for example, when engine start-up is not uniform, also due to low temperature.

The vehicle body chassis 11 is a structure formed by joining a plurality of pressure-molded parts and includes a front tube 21, provided at its front end, a main chassis 22, which extends behind the front tube 21, a central chassis 23, which extends down from an intermediate part of the main chassis 22, a sub-chassis 24, connected to a rear part of the main chassis 22 and to a lower part of the central chassis 23, and a descending chassis 26. which extends back and down from the front tube 21.

The front tube 21 has a front fork 13 mounted in a rotating manner thereon, and a handlebar 31 and a front (road) wheel 32 are connected, in each case, to the upper and lower parts of the front fork 13. The main fuel tank 33, for storing the main fuel, is mounted on and across a front part of the main chassis 22, and a seat 34 is mounted on the rear part of the main chassis 22. The auxiliary fuel tank, for storing the auxiliary fuel, is located inside the main fuel tank 33.

The central chassis 23 supports the engine 12, along with the descending chassis 26. The pivot shaft 36 supported by the central chassis 23 serves as an axle that allows the vertical rotational movement of the rear fork 14. The rear (road) wheel 35 is connected to the rear end of the rear fork 14.

The rear shock absorber unit 37 is connected and extends between the respective rear parts of the rear fork 14 and the main frame 22. The descending frame 26 supports the engine 12 by means of a support 38.

Transmission 41 is provided in one piece with a rear part of the engine 12 and a cylinder head 44 is mounted to a cylinder section 43, which extends upwards, from the engine 12. An air intake device 46 is connected to a rear part of the cylinder head 44, and an exhaust device 47 is connected to a front part of the cylinder head 44.

The air intake device 46 includes an intake tube 51 connected at one end to the cylinder head 44, a throttle valve body 52 connected at one end to the other end of the intake tube 51, and an air purifier 54 connected to the other end of the throttle valve body 52 by means of a connecting tube 53.

The exhaust device 47 includes an exhaust pipe 56, connected at one end to a front part of the cylinder head 44 and extending downwards and backwards from the front part of the engine 12, and a silencer 57, connected to the other end of the exhaust pipe 56 and extending backwards.

In the figure, reference number 61 designates a front hood, 62, a front lamp, 63, a front fender, 64, a side cover, which folds over the sides of the air purifier 54, 66, a rear Ia cover, 67, a rear fender, 68, a rear lamp, 71, a main support, 72 a transmission output shaft 41, 73, a drive sprocket, connected to the output shaft 72, 74, a driven sprocket, joined in a piece to the rear wheel 35, 76, a chain, which extends between and is wrapped around its opposite sides on the drive sprocket and the driven sprocket 73 and 74, and 77, a chain cover.

Figure 2 is a side view, showing main sections of the fuel dispensing device according to the embodiment of the invention. The primary fuel filter 141 for filtering the main fuel (hereinafter simply called fuel) is disposed within a fuel pump 92, which, in turn, is connected to a lower part 91 of the main fuel tank 33, and a secondary fuel filter 143 for further filtering the fuel is connected to the fuel pump 92 by means of a fuel supply tube 142 made of resin. The fuel supply tube 144 is connected at one end to the secondary fuel filter 143 and extends upwards to be connected at its other end to a fuel injector valve (injector) 94, which is disposed in the body of the throttle valve 52, located above the secondary fuel filter 143; that is, the fuel injector valve 94 is connected to the secondary fuel filter 143 by means of the tube 144. The secondary fuel filter 143 is located downstream of the primary fuel filter 143, which is housed within the fuel pump 92. As will be described later with regard to Figure 3, the fuel distribution piping (not shown in Figure 2) extends from the secondary fuel filter 143 to the main fuel tank 33.

The left side (i.e., the side visible in figure 2) of the secondary fuel filter 143 is covered with the side cover 64 (see figure 1) and, therefore, is not exposed to the outside, so that an enhanced external appearance of the vehicle can be obtained.

The secondary fuel filter 143 has a smaller filtration mesh or pore size than the primary fuel filter 141; for example, the pore size of the secondary fuel filter 143 is 30 µm, while the pore size of the primary fuel filter 141 is 70 µm. Thus, the primary fuel filter 141 collects relatively large dust particles, and the secondary fuel filter 143 can collect finer dust particles that pass through the primary fuel filter 141. Because this arrangement prevents the secondary fuel filter 143 from collecting relatively large dust particles, the secondary fuel filter 143 may be less prone to clogging. In addition, the primary fuel filter 141 may also be less prone to clogging due to its large pore size.

Consequently, the present embodiment can achieve longer exchange or replacement cycles for both the primary fuel filter 141 and the secondary fuel filter 143, so that the number of times maintenance work needs to be performed can be reduced. Furthermore, a high current flow rate of fuel passing through the primary fuel filter 141 and the secondary fuel filter 143 can be maintained for a long period of time. As a result, this design can appropriately handle situations where the fuel flow rate increases rapidly, such as during vehicle start-up, acceleration, or similar operations.

Furthermore, since the secondary fuel filter 143 is located at the rear of the engine 12, the intake device 46 (more specifically, the throttle valve body 52) and the secondary fuel filter 143 can be positioned close to each other. In this way, the present embodiment can reduce the length of the fuel supply pipe 144, which is connected between the secondary fuel filter 143 and the fuel injector valve 94 of the throttle valve body 52, so that the installation of the necessary fuel piping can be significantly facilitated.

Figure 3 is a perspective view showing the main sections of the fuel supply device according to the embodiment of the invention. The secondary fuel filter 143 is arranged laterally outside the central chassis 23 and fixedly attached to the central chassis 23 by means of a support 146. The fuel return pipe 135 extends upwards from the secondary fuel filter 143, to be connected to the main fuel tank 33.

The fuel return pipe 135 is, for example, in the form of a rubber hose, which is shorter in length and larger in outer diameter or width than the fuel supply pipe 142, made of resin, and is thus easily distinguishable from the fuel supply pipe 142; therefore, it is possible to avoid an assembly error when assembling the fuel supply pipe 142 and the fuel return pipe 135 in the secondary fuel filter 143.

The fuel supply tube 144 is arranged to extend from the downstream side of the secondary fuel filter 143 upwards, to the throttle valve body 52 (more specifically, to the fuel injector valve 94 of the throttle valve body 52), located above the secondary fuel filter 143. Thus, air inside the secondary fuel filter 143 easily exits the filter 143 and flows into the fuel injector valve 94 of the throttle valve body 52 through the fuel supply tube 144; this arrangement allows for uniform fuel supply through a single fuel passage, including the secondary fuel filter 143.

The structural components described above are arranged in a region of the main fuel tank 33 for the fuel injector valve 94, that is, the main fuel tank 33, primary fuel filter 141 (see figure 2), fuel pump 92, fuel supply pipe 142, secondary fuel filter, fuel return pipe 135, fuel supply pipe 144, The throttle valve body 52 and fuel injector valve 94 together constitute the fuel supply device 150 of the invention.

Due to the placement of the secondary fuel filter 143 laterally outside the central chassis 23, as observed above, maintenance work, such as replacing the secondary fuel filter 143, can be easily performed from one side of the vehicle. Furthermore, it is possible to increase the capacity of the secondary fuel filter 143, so that undesirable fuel pulsation can be more easily reduced.

Figure 4 is a cutaway view of the fuel pump used in the fuel dispensing device 150. The fuel pump 92 includes a lower housing 151 made of resin, fixedly attached to the main fuel tank 33 (see figure 2), an upper housing 152, made of metal or resin, fixedly attached to an upper part of the lower housing 151, and a drive section 153, disposed within the upper housing 151 and the lower housing 152.

The lower housing 151 includes a flanged portion 155 for connection to the main fuel tank 33, a fuel passage 156 through which fuel is supplied to the drive section 153, and a discharge opening 157 connected to the fuel passage 156. The primary fuel filter 141 is housed in the lower storage compartment 151.

The upper casing 152 has a plurality of suction openings 161 formed therein, for drawing in fuel. The drive section 153 includes a motor, and a pump driven by the motor. The primary fuel filter is disposed upstream of the drive section 153 of the fuel pump 92.

As indicated by arrows in the figure, fuel is drawn in through the suction openings 161 of the upper casing 152 and passes through the primary fuel filter 141, after which the fuel rises in the drive section 153 and passes through the fuel passage 156 to the discharge opening 157. Then, through the discharge opening 157, the fuel flows into the fuel supply tube 142 of figure 2 and then reaches the secondary fuel filter 143, shown in figure 2.

Figures 5A and 5B are, in each case, side and perspective views, which explain the secondary fuel filter 143 and its mounting structure in the present embodiment.

As shown in figure 5A, the support 146, which has a plate and metal shape, is fixed to the central chassis 23, and the secondary fuel filter 143 is supported by the support 146.

The secondary fuel filter 143 includes a housing (member) 171 made of resin, and a filter body 181 (shown in figure 7) made of non-woven material and housed within the housing 171. The housing 171 includes a tubular housing body 173, and a housing cover 174, which closes an upper opening of the housing body 173.

The housing body 173 has a fuel discharge opening 171b provided in its bottom part. The housing cover 174 has in its upper part a fuel suction opening 171a and a fuel return opening 171c, to redirect the fuel to the main fuel tank 33 (see figure 2).

As shown in figure 5B, the central chassis 23 includes a side part 23a, which extends in one direction (i.e., left-to-right) towards the vehicle, a longitudinal part 23b, which extends in a direction towards the front of the vehicle, from one end of the side part 23a, a curved part 23c, which extends in directions towards the front and into the vehicle, and a front part 23d, which extends in the direction towards the front of the vehicle, from the front end of the curved part 23c. Support 146 is fixed to the longitudinal part 23b, and the secondary fuel filter 143 is fixed to support 146.

By forming the central chassis 23 in a curved configuration, as observed above, it is possible to increase the rigidity, particularly bending rigidity, of the central chassis 23 in the front-to-rear and vehicle width directions.

If an imaginary straight line 165 is drawn along the longitudinal part 23b, as illustrated in figure 5B, the secondary fuel filter 143 is located laterally outside the straight line 165 and therefore outside the central chassis 23. The central chassis 23 has, on its outer side surface, corresponding in position to the inner surface of the secondary fuel filter 143, a stepped part 23f, as a concave part in the direction towards the vehicle body, which is constituted by the curved part 23c mentioned above and the front part 23d.

Figures 6A and 6B are plan views, showing the general operation of the mounting structure for the secondary fuel filter 143.

In Figure 6A, the support 146 includes a rear flat plate portion 146a, welded to the longitudinal portion 23b of the central chassis 23, a curved portion 146b, which is curved laterally outward from the front end of the rear flat plate portion 146a, and a front flat plate portion 146c, which extends forward from the front end of the curved portion 146b. The front flat plate part 146c is connected to a housing body 173 of the secondary fuel filter 143, extending through a part of the housing body 173.

For example, when an external force acts on the secondary fuel filter 143 from one side, as indicated by a white arrow, the external force is transmitted to the support 146 by means of the secondary fuel filter 143, so that the curved part 146b and the part located in front of the curved part 146 are bent towards the central chassis 23, as shown in figure 6B. At this point, the secondary fuel filter 143 moves into the stepped or concave part 23f of the central chassis 23.

With the inwardly concave part 23f, formed in the central chassis 23, so as to allow the secondary fuel filter to move into the inwardly concave part 23f when an external force acts on the secondary fuel filter 143, a movable quantity of the secondary fuel filter 143 can be increased, and the increased movable quantity allows an external force, acting on the secondary fuel filter, to be absorbed with increasing ease.

Figure 7 is a cross-sectional view of the secondary fuel filter 143, used in the present embodiment of the invention. The secondary fuel filter 143 includes the housing 171, with the housing body 173 and the housing cover 174, which closes the upper opening of the housing body 173, as observed above, and a filter element 176 housed within the housing 171. The housing body 173 has the fuel suction opening 171, for drawing in fuel, and the fuel return opening 171c, for returning fuel to the main fuel tank 33 (see figure 3). The housing cover 174 has the fuel discharge opening 171b, for discharging fuel.

The filter element 176 includes the bag-shaped filter body 181, made of non-woven material, and a connection opening 182, which communicates with the interior of the filter body 181 and is connected to the fuel suction opening 171a of the housing cover 174.

The secondary fuel filter 143 also includes a pressure regulator 186, arranged in one piece with the lower surface of the housing cover 174, and when a fuel pressure within the secondary fuel filter 143 exceeds a predetermined value, this pressure regulator 186 operates to redirect fuel to the main fuel tank 33, thereby regulating the fuel pressure within the secondary fuel filter 143. In addition, a check valve 188 is arranged within the fuel discharge opening 171b of the housing body 173.

The pressure regulator 186 includes a bottom-cylinder regulator housing 191, made of resin, installed in a cylindrical part 174a, formed in one piece with the bottom surface of the housing cover 174, a spherical valve member, made of steel, for opening/closing a through hole 191a, formed in the bottom of the regulator housing 191, and a compression spiral spring 193, for normally forcing the valve member 192 to close the through hole 191a. The passage hole 191a communicates with the interior of the filter element 176, and an upper opening 191b of the regulator housing 191 communicates with the interior of the fuel return opening 171c.

The regulator housing 191 has its lower terminal surface 191A supported on a stepped part 173, connected between a small diameter tube part 173A and a large diameter tube part 173B of the housing body 173.

Reference number 174 indicates an annular fitting part, which is formed in one piece with the lower surface of the housing cover 174 and fits into an upper part of the housing body 173, and 195 indicates an O-ring, which forms a seal between the tubular part 174a and the regulator housing 191.

The check valve 188 includes a valve housing 196, a valve body 197 arranged for vertical movement within the valve housing 196, and a spring 198, for normally compressing a semi-spherical head portion 197a of the valve body 197 against a tapered valve seat 196a. In the figure, the valve body 197 closes the tapered valve seat 196a.

The fuel inside the housing 171 is allowed to flow from inside the secondary fuel filter 143 to the outside (i.e., to the fuel injector valve 94 (see figure 3)), through the fuel discharge opening 171b, pushing down the valve body 197, against the elastic compression force of the spring 198. Fuel backflow from fuel injector valve 94 to secondary fuel filter 143 can be prevented by raising the valve body 197, so that the head part 197a rests against the valve seat 196a to close the fuel passage.

During the operation of engine 12, the fuel pump 92 operates in such a way that the pressure of the fuel pump 92 pushes the valve body 197 downwards, against the elastic compression force of the spring 198, thus causing the fuel to flow to the fuel injector valve 94 (see figure 2), through the fuel discharge opening 171b and the fuel supply pipe 144. so that the fuel injector valve 94 sprays the fuel towards the engine.

When engine 12 is switched off, fuel pump 92 is switched off, so that valve body 197 is pushed upward by spring 198 to abut valve seat 196a, thereby closing the fuel passage. In this way, the fuel passage, which extends from the fuel discharge opening 171b to the fuel injector valve 94, is maintained at a high pressure.

After deactivating fuel pump 92, it is desirable to maintain the internal pressure in the fuel line at a high level in order to ensure that the fuel passage functions properly immediately after fuel pump 92 is activated the next time. However, even if the internal pressure in the fuel line is maintained at a high level, the internal pressure gradually decreases due to a minimal amount of fuel leaking from pressure regulator 186 to the discharge side. This is why check valve 188 is located on the discharge side of pressure regulator 186.

Figures 8A and 8B are, in each case, perspective views and fragmented, explosion-frame views of secondary fuel filter 143.

In the housing body 173, the large diameter tube section 173B is formed continuously with the upper part of the small diameter tube section 173A, by means of the stepped connection section 173C. The pressure regulator 186 shown in figure 7 is disposed within the large diameter tube section 173B. The internal passage 171d, which communicates with the fuel suction opening 171a, is arranged in one piece with the housing cover 174. The filter element 176 has a bag-shaped filter body 181 made of non-woven material, a fuel passage 182a that communicates with the interior of the bag-shaped filter body 181, and the connection opening 182 mentioned above, connected to the internal passage 171d of the housing cover 174. The connection opening 182 is located in a substantially central position within the width of the filter body 181.

Figures 9A and 9B are explanatory views of the filter element.

176 used in the present embodiment of the invention, of which Figure 9A is a cross-sectional view taken along line 9-9 of Figure 8B and Figure 9B is a perspective view showing the filter element 181 when housed in the filter housing 171.

In Figure 9A, the filter body 181 of the filter element 176 is in the form of a pouch, formed by overlapping a mesh 181B made of resin (e.g., polypropylene (PP)) over a three-layer nonwoven material 181A, made of resin (e.g., polypropylene (PP)), then folding the overlapping mesh 181 and the material 181A in half. such that the nonwoven material 181A is positioned within the mesh 181B and then welding the respective edge parts of opposite sides of the mesh 181B and the material 181A. The filter body 181 is connected to a terminal part of the connection opening 182 in such a way that it is fitted between an external flange 182b, which is molded in one piece with the connection opening 182 and extends through the wall thickness of the filter body 181, and an internal flange 182c, which is located inside the filter body 181 and adhered to the external flange 182 by ultrasonic welding, adhesive or similar, or joined to the external flange 182 by a slip-fit ​​joint with the latter.

Figure 9B shows the filter body 181 wound or bent cylindrically, with the connection opening 182 positioned inside the body 181 when the filter element 176 is to be placed in the housing 171 (see Figure 8B). Depending on the size of the filter body 181, the filter body 181 may be wound once or twice to be placed in the filter housing 171.

By placing the filter body 181, which is coiled or bent cylindrically in this way, into a housing 171, the filter body 181 can be compactly housed in the housing 171, and thus the housing 171 can be formed into a reduced size. That is, a size reduction of the secondary fuel filter 143 can be achieved.

In Figure 9B, the connection opening 182 is attached to and retained on an inner wall 181a of the cylindrically rolled or bent filter cup 181 and extends upwards through the upper opening of the cylindrical filter body 181 in an outward orientation. Therefore, no protruding part is formed on an outer wall 181b of the cylindrical rolled or bent part of the filter body 181, which allows a reduction in the size of the filter housing 171. Furthermore, since the internal space of housing 171 can be efficiently utilized in the manner mentioned above, the filter body 181 can have an increased area.

Since the pressure regulator 186 is located downstream of the filter body 181, the fuel, which has been filtered through the filter body 181 of the secondary fuel filter 143, is sent back to the main fuel tank 33 (see figure 3) via the pressure regulator 186. Therefore, dust contained in the fuel can be replenished and passed through the primary fuel filter (see figure 2), so that clogging of the primary fuel filter 141 can be avoided more safely. Consequently, the replacement cycle of the primary fuel filter 141 can be extended, allowing for improved maintenance of the fuel dispensing device.

Furthermore, since the pressure regulator 186 is formed in one piece with the housing 171 of the secondary fuel filter 143, the present embodiment can significantly reduce the number of component parts required and therefore the cost of the fuel dispensing device.

Furthermore, with the lower end surface 191A of the regulator housing 191 supported on the stepped part 173C of the housing body 173, the regulator housing 191 can be fitted between the stepped part 173C and the housing cover 174 and thus properly secured to the housing 171, simply by attaching the housing cover 174 to the housing body 171, after equipping the regulator housing 191 with the tubular part 174a of the housing cover 174. Thus, the present embodiment can simplify the structure for mounting the pressure regulator 186 in the housing 171.

Furthermore, as the secondary fuel filter 143 is disposed downstream of the fuel pump 92 and the pressure regulator 186 is disposed downstream of the filter body 181, as described above, the fuel that has passed through the filter body 181 is sent back to the main fuel tank 33 (see figure 2) by means of the pressure regulator 186, with most of the dust removed or filtered from the fuel. Therefore, in the case where another filter, namely the primary fuel filter 141, is located inside the fuel pump 92, the replacement cycle of the primary fuel filter 141 can be extended, so that the present embodiment can reduce the number of times maintenance work needs to be performed.

Furthermore, with the fuel return pipe 135, which extends upwards from the pressure regulator 186 to the main fuel tank 33, as shown in figure 3, air accumulated inside the secondary fuel filter 143 can easily flow to the main fuel tank 33, located above the secondary fuel filter, and thus the fuel supply through the fuel passage can be carried out uniformly.

Furthermore, housing 171 consists of housing body 173 and housing cover 174, and the fuel suction opening 171a and the fuel return opening 171c are arranged offset from a central axis 200 of the housing cover 174, as shown in figure 7. Thus, in the case where the pressure regulator 186 is positioned close to the fuel return opening 171c, as illustrated in figure 7, it is possible to improve the freedom of arrangement and shape of the pressure regulator 186, and thus the housing 171 can be made compact in size.

Furthermore, as the housing 171 has the stepped part 173C, which protrudes radially outwards, and the lower end of the pressure regulator 186, that is, the surface of the lower end 191A of the regulator housing 191, is supported on the stepped part 173C, the structure for supporting the pressure regulator 186 can be simplified, so that the present embodiment can avoid a substantial cost increase of the housing 171 and, therefore, of the secondary fuel filter 143.

Figures 10A and 10B show cross-sectional views of the secondary fuel filter according to the present embodiment of the invention.

Figure 10A shows a state in which no fuel has been supplied to the filter body 181 of the secondary fuel filter 143, and in which the bag-shaped filter body 181 is left rolled up and uninflated. In the figure, reference number 173a indicates the inner surface of the housing body 173 and reference number 173b indicates a plurality of convex parts 173b that project into the inner surface 173a of the housing body 173.

Figure 10B shows a state in which fuel has been supplied through the connection opening 182 of the secondary fuel filter 143 to the filter body 181, and in which the filter body 181 has been inflated due to an increase in internal fuel pressure. In this state, the supplied fuel gradually flows from the connection opening 182 towards the discharge end, as indicated by arrows, while the fuel passes through the filter body 181, from the inside to the outside of the body 181. At this moment, a plurality of intermediate spaces 201 is formed by the plurality of inwardly convex parts 173b, between the inflated filter body 181 and the inner surface 173a of the housing body 173, and the fuel flows into the intermediate spaces 201, so that it flows into other regions through the intermediate spaces 201. In this way, the present method can prevent undesirable fuel stagnation, thus achieving improved fuel filtration efficiency.

Furthermore, in the fuel dispensing device 150, as illustrated in figures 2, 7, and 10A and 10B, the secondary fuel filter 143 is located outside the fuel tank 33, the exterior of the secondary fuel filter 143 is covered with the filter housing 171, and the pressure regulator 186, for regulating the pressure inside the secondary fuel filter 143, is provided in a piece with the filter housing 171. so that the fuel that passed through the pressure regulator

186 It is then sent back to the fuel tank 33. Furthermore, the secondary fuel filter 143 is bag-shaped, and the fuel is filtered by the secondary fuel filter 143 as it passes through the filter body 181, from the inside to the outside of the filter body 181. Therefore, the filter body 181 can be compactly housed in the housing 171, and thus the housing 171 can be formed in a reduced size.

Furthermore, since the filter body 181 is inflated and stably maintained in its inflated shape when fuel is passed through the filter body 181, from the inside to the outside of the filter body 181, no special frame is required for the filter member 181. Therefore, the present embodiment can reduce the number of component parts required for the filter body 181.

Furthermore, since the filter body 181 to be housed within the housing 171 can be easily changed in shape when necessary, the present embodiment can increase the freedom of arrangement of the pressure regulator 186 and the fuel return opening 171c.

It is observed that, although the present embodiment has been described above in relation to the case where the pressure regulator 186 is provided in a part with the housing cover 174 of housing 171, as shown in figure 7, the present invention is not limited to this; for example, the pressure regulator 186 may be provided in the housing body 173.

Furthermore, as described above, the filter body 181 is formed in a bag shape, the fuel is filtered as it passes from the inside to the outside of the bag, and the mesh 181B, which is less prone to deformation, warping and the like than the nonwoven material 181A, is laid outside the nonwoven material 181A. In this way, the filter body 181 can maintain its inflated shape when fuel is supplied to the bag-shaped filter body 181. Therefore, no special frame is required for the filter body 181, and thus the present embodiment can achieve a substantial reduction in the cost of the secondary fuel filter 143. Furthermore, the secondary fuel filter

143 It can be built in an even smaller size.

Furthermore, the filter body 181 is supported, in part, by the convex parts 173b, which project into the inner surface 173a. Thus, when the fuel flows into the filter body 181, a plurality of intermediate spaces 201 can be ensured between the inflated filter body 181 and the inner surface 173a of the housing body 173, and the fuel inside the secondary fuel filter 143 is allowed to flow into the intermediate spaces 201 through the filter body 181. Consequently, this embodiment can suppress a decrease in fuel stream flow, or fuel stagnation, and thus increase fuel filtration efficiency.

Furthermore, since the primary fuel filter 141 is located upstream of the fuel pump 92 (more specifically, upstream of the drive section 153), as seen in figures 2, 4 and 5, and the secondary fuel filter 143, made of non-woven material with a smaller pore size than the primary fuel filter 141, is located downstream of the fuel pump 92, the primary fuel filter 141 may have a larger pore size. In this way, the present embodiment can extend not only the life of the primary fuel filter 141, but also the life of the fuel pump 92, located downstream of the primary fuel filter 141.

Furthermore, with the 143 secondary fuel filter, made of non-woven material, fuel filtration efficiency can be increased significantly, and the 143 secondary fuel filter can have a reduced surface area, allowing it to be built in a compact size. Furthermore, since fuel filtration is carried out in cooperation by the primary fuel filter 141 and the secondary fuel filter 143, the present embodiment can significantly extend the life of the secondary fuel filter 143, compared to the case where only one of these fuel filters is provided.

Although the present embodiment has been described above in relation to the case where the bag-shaped filter body 181 is positioned within the housing 171 in a rolled or folded form, the present invention is not limited in this manner. For example, the filter body 181 may be positioned within the housing 171 in a folded form.

In this case, the shape of housing 171 is not limited to a tubular or cylindrical shape, as indicated above, and housing 171 can be of any other desired shape, such as a cube, parallelepiped, or square pyramid.

INDUSTRIAL APPLICABILITY

The fuel dispensing device and fuel filter structure described above in the present invention are particularly suitable for application to motorcycles.