JP7720875B2 - fuel supply device - Google Patents

Description

The present invention relates to a fuel supply device.

Traditionally, efforts have been made to mitigate or reduce the impact of climate change, and research and development into reducing carbon dioxide emissions has been carried out to achieve this.
For example, Patent Document 1 discloses a structure in which a fuel chamber is provided upstream of an injector and the fuel stored in the fuel chamber is heated by a heater in order to ensure startability at low temperatures in an internal combustion engine that is operated with fuel containing alcohol fuel.

Patent No. 4834728

When applying the above-mentioned conventional technology to reduce carbon dioxide emissions, it is more convenient to have a shorter time between when the heater starts heating and when the fuel accumulated upstream of the injector is fully heated. However, in systems where pre-pressurized fuel is supplied to the fuel chamber in which the heater is located, there is generally no return pipe to return the fuel in the chamber to the fuel tank (upstream of the pump). This makes it particularly difficult to heat the fuel evenly within the fuel chamber during pre-heating before the engine starts, as fuel injection has not yet begun and no active fuel flow occurs, requiring the system to rely solely on natural convection.

The present invention aims to quickly heat the fuel in the fuel chamber in a fuel supply device that heats the fuel supplied to the injector.

As a means for solving the above problems, a first aspect of the present invention includes an injector (40) that supplies fuel to be burned in a combustion chamber of an internal combustion engine (10), a fuel chamber section (50) that is connected to the upstream side of the injector (40) and that stores the fuel to be supplied to the injector (40), a heater section (62) that is disposed in the fuel chamber section (50) and that heats the fuel stored in the fuel chamber section (50), a fuel tank (15) that stores fuel for the internal combustion engine (10), a fuel pump (42) that pressure-feeds the fuel in the fuel tank (15) to the injector (40), and a fuel pump (42) that pressure-feeds the fuel in the fuel tank (15) to the injector (40). a pressure adjusting means (46) for adjusting the pressure of fuel pumped by a fuel pump (42) to a specified pressure for injection from the injector (40), and a fuel feed path (44) connected to the fuel chamber portion (50) and for feeding the fuel whose pressure has been adjusted by the pressure adjusting means (46) into the fuel chamber portion (50), the fuel chamber portion (50) is provided with a throttle portion (56) that throttles the flow path of the fuel feed path (44), and a fuel return path (55) is connected to the fuel chamber portion (50) and returns the fuel in the fuel chamber portion (50) to a side upstream of the fuel pump (42).
According to this configuration, a throttle portion that throttles the flow path of the fuel feed path is provided in the fuel return path, which returns fuel from the fuel chamber to the upstream side of the fuel pump. This allows some of the fuel to be returned to the upstream side of the fuel pump from the fuel return path while maintaining the fuel pressure in the fuel chamber. This allows the fuel to flow within the fuel chamber during preheating without fuel injection from the injector. This promotes agitation of the fuel within the fuel chamber, allowing for uniform heating and shortening the preheating time before fuel injection.

In a second aspect of the present invention, in the first aspect, a return control valve (57) that opens and closes a flow path of the fuel return path (55) is provided in the fuel return path (55), and the return control valve (57) opens the flow path to allow the return of fuel before fuel injection from the injector (40) starts, and closes the flow path to restrict the return of fuel after fuel injection from the injector (40) starts.
According to this configuration, by opening the return control valve provided in the fuel return path until fuel injection starts (preheat period), a forced flow of fuel is created in the fuel chamber, promoting natural convection of the fuel and shortening the preheat period. After fuel injection starts, by closing the return control valve, the outflow of heated fuel is prevented, reducing the energy consumption of the heater device and enabling efficient fuel heating.

A third aspect of the present invention is the first or second aspect, wherein the fuel chamber portion (50) is provided with an outlet (54a) to the fuel return path (55), and the outlet (54a) is positioned below the vertical center of the fuel chamber portion (50).
According to this configuration, the rate at which the temperature rises within the fuel chamber can be increased by returning the relatively cooler fuel that accumulates in the lower part of the fuel chamber after heating, rather than returning the relatively hotter fuel that accumulates in the upper part of the fuel chamber.

A fourth aspect of the present invention is any one of the first to third aspects, wherein the fuel chamber portion (50) has an outlet (54a) to the fuel return path (55) and an inlet (53a) from the fuel feed path (44), and the inlet (53a) is positioned above the outlet (54a).
With this configuration, a flow can be formed from the inlet to the outlet from the top to the bottom, and the formation of a flow in the opposite direction to the bottom-to-top flow caused by heating from the heater section promotes agitation of the fuel within the fuel chamber section, thereby enabling the fuel chamber section to be heated evenly.

A fifth aspect of the present invention is an internal combustion engine (10) including an injector (40) that supplies fuel to be burned in a combustion chamber of the internal combustion engine (10), a fuel chamber (50) connected to the upstream side of the injector (40) and storing the fuel to be supplied to the injector (40), a heater (62) disposed in the fuel chamber (50) and heating the fuel stored in the fuel chamber (50), a fuel tank (15) that stores fuel for the internal combustion engine (10), a fuel pump (42) that pressure-feeds fuel in the fuel tank (15) to the injector (40), pressure-regulating means (46) that adjusts the pressure of the fuel pumped by the fuel pump (42) to a specified pressure for injection from the injector (40), and a pressure-regulating means (46) connected to the fuel chamber (50) and configured to adjust the pressure of the fuel to a specified pressure for injection from the injector (40). and a fuel feed path (44) that sends fuel whose pressure has been adjusted by a pressure adjusting device (6) into the fuel chamber portion (50), the fuel chamber portion (50) is connected to a fuel return path (55') that returns the fuel in the fuel chamber portion (50) to a side upstream of the fuel pump (42), the fuel feed path (44) is provided with a check valve (45) that allows the flow of fuel toward the fuel chamber portion (50) and regulates the flow of fuel toward the fuel pump (42), and the fuel return path (55') is provided with a pressure adjusting valve (56') that does not open until the pressure of the fuel in the fuel chamber portion (50) reaches a second specified pressure that is higher than the specified pressure and opens when the pressure exceeds the second specified pressure.
According to this configuration, a check valve is provided in the fuel feed path that sends pressure-regulated fuel to the fuel chamber, and a second pressure regulator that opens when fuel pressure in the fuel chamber is higher than that in the fuel feed path is provided in the fuel return path that returns fuel from the fuel chamber to a location upstream of the fuel pump. This allows some high-pressure fuel to be returned to the upstream side of the fuel pump through the fuel return path while maintaining the fuel pressure in the fuel chamber. This allows excess pressure to be released through the fuel return path even if an unintended pressure increase occurs during fuel preheating. This allows the allowable pressure of fuel hoses, injectors, etc. to be set appropriately without unnecessarily increasing, thereby minimizing increases in component costs.

A sixth aspect of the present invention is the fifth aspect, wherein the fuel chamber portion (50) is provided with an outlet (54a') to the fuel return path (55'), and the outlet (54a') is located at the top of the fuel chamber portion (50).
With this configuration, fuel vapor in the fuel chamber accumulates at the top of the fuel chamber, so by locating the outlet of the fuel return path at the top, the fuel vapor can be efficiently diverted into the fuel return path, resulting in quick pressure reduction.

According to the present invention, in a fuel supply device that heats fuel to be supplied to an injector, the fuel in the fuel chamber can be quickly heated.

1 is a right side view of a motorcycle according to an embodiment of the present invention. FIG. 2 is an enlarged view of a main part of FIG. 1 . FIG. 2 is a top view of the vicinity of an intake passage part of the motorcycle. FIG. 2 is a configuration diagram of a fuel supply device of the motorcycle. 3 is an explanatory diagram showing a configuration relating to a fuel tank and a fuel chamber in the first embodiment of the fuel supply device. FIG. FIG. 10 is an explanatory diagram showing a configuration relating to a fuel tank and a fuel chamber in a second embodiment of the fuel supply device. 10 is an explanatory diagram showing a modified example of the fuel chamber portion. FIG.

Embodiments of the present invention will be described below with reference to the drawings. Note that, unless otherwise specified, the directions of front, rear, left, right, etc. in the following description are the same as those in the vehicle described below. In addition, the arrow FR indicating the front of the vehicle, the arrow LH indicating the left side of the vehicle, the arrow UP indicating the top of the vehicle, and the line CL indicating the center of the left and right sides of the vehicle body are shown in appropriate locations in the drawings used in the following description.

<Entire vehicle>
As shown in Figure 1, this embodiment is applied to a motorcycle 1, which is a saddle-ride type vehicle. A front wheel 2 of the motorcycle 1 is supported at the lower ends of a pair of left and right front forks 3. The upper parts of the left and right front forks 3 are supported by a head pipe 21 at the front end of a body frame 20 via a steering stem 4. A steering bar handle 6 is attached to the upper part of the steering stem 4.

The rear wheel 7 of the motorcycle 1 is supported by the rear end of the swing arm 8. The front end of the swing arm 8 is supported by a pivot frame 23 located in the middle between the front and rear of the body frame 20. Note that "middle" as used in this embodiment refers not only to the center between the two ends of an object, but also to the inner range between the two ends of an object. The rear wheel 7 is connected to the power unit PU of the motorcycle 1 via a chain-type transmission mechanism located, for example, on the left rear side of the body.

The power unit PU is an integrated unit that includes an engine (internal combustion engine) 10, which is the prime mover of the motorcycle 1, and a clutch and transmission (neither of which are shown) that connect and disconnect the output of the engine 10 and change the speed, and is fixedly supported on the body frame 20.
The engine 10 has a cylinder 12 that stands upright above the front of a crankcase 11. An intake passage part 32 is connected to the rear of the cylinder 12. An exhaust pipe 14 is connected to the front of the cylinder 12. The exhaust pipe 14 runs from the front of the engine 10 downward, is routed to, for example, the right rear, and is connected to an exhaust muffler 14a that is located on the right rear of the vehicle body.

Above the engine 10 is located a fuel tank 15 that stores fuel to be supplied to the engine 10. Behind the fuel tank 15 is located a seat 16 on which the driver and rear passenger sit. On both sides of the lower body, there are located a pair of left and right main steps 17 on which the driver places their feet, and a pair of left and right pillion steps 18 on which the rear passenger places their feet.

The body frame 20 comprises a head pipe 21, a main frame 22 extending rearward and downward from the upper part of the head pipe 21, a pivot frame 23 extending rearward and downward from the lower rear end of the main frame 22 at a steeper incline than the main frame 22, a down frame 27 extending rearward and downward from the lower part of the head pipe 21 at a steeper incline than the main frame 22, seat rails 25 extending rearward from the rear of the main frame 22, and a support frame 26 extending upward and rearward from the middle part of the pivot frame 23 above and below.

The engine 10 can be operated using ethanol or a blend of gasoline and ethanol (hereinafter collectively referred to as ethanol fuel) in addition to gasoline. In other words, the motorcycle 1 is a flexible fuel motorcycle (FFM) that can run on multiple types of fuel.
The cylinder 12 of the engine 10 has, in order from the crankcase 11 side, a cylinder body 12a, a cylinder head 12b, and a head cover 12c.

Also referring to Figure 2, the downstream end of an intake passage component 32 including a throttle body 33 is connected to the rear (intake side) of the cylinder head 12b. In the figure, reference numeral 34 designates an air cleaner box to which the upstream end of the intake passage component 32 is connected, reference numeral 35 designates a connecting tube connecting the throttle body 33 and the air cleaner box 34, and reference numeral 36 designates an intake pipe member connecting the throttle body 33 and the cylinder head 12b. The connecting tube 35 and the intake pipe member 36 are included in the intake passage component 32.

<Fuel supply device>
As shown in FIG. 4, the motorcycle 1 includes a fuel tank 15, a fuel pump 42, an injector (fuel injection valve) 40, and the like, which constitute a fuel supply system 40A.
Fuel in the fuel tank 15 is drawn into, for example, a fuel pump 42 disposed within the fuel tank 15 and discharged downstream. The fuel pump 42 is immersed in the fuel in the fuel tank 15, thereby drawing in the fuel within the fuel tank 15. For example, the fuel pump 42 includes a pump body that pumps the fuel and a primary filter that filters the fuel on the suction side (upstream side) of the pump body (neither of which is shown).

Referring also to Figure 5, the downstream path (fuel feed path 44) extending from the discharge portion 43 of the fuel pump 42 to the injector 40 is provided with a check valve 45 and pressure regulating means (pressure regulator 46). The check valve 45 allows fuel to flow from the fuel pump 42 side to the downstream side (the injector 40 side) and restricts fuel flow in the opposite direction. By providing the check valve 45 on the discharge side of the fuel pump 42, the pressurized state (residual pressure) of the fuel downstream of the check valve 45 is maintained when the engine 10 is stopped (when the fuel pump 42 is stopped) due to parking, etc. Therefore, when the engine 10 is restarted, the fuel can be pressurized to the pressure required for fuel injection with little pump drive.

The pressure regulator 46 adjusts the pressure of the fuel discharged from the fuel pump 42 to a predetermined pressure. Excess pressure (fuel) is returned to the fuel tank 15 via the return flow path 47. The fuel pressure adjusted by the pressure regulator 46 is supplied to the injector 40 via a feed hose 48 extending to the outside of the fuel tank 15. In FIG. 5, the check valve 45 and the pressure regulator 46 are shown separate from the fuel pump 42, but at least one of the check valve 45 and the pressure regulator 46 may be integrated with the fuel pump 42. As a pressure adjustment means instead of the pressure regulator 46, a configuration in which the fuel pressure is adjusted by drive control (e.g., rotation speed control) of the fuel pump 42 may also be used.

Fuel discharged from the fuel pump 42 is supplied into a chamber T3 of a fuel chamber 50 connected to the injector 40. A heater unit 62 faces the chamber T3 and is capable of heating the fuel stored in the chamber T3.
The injector 40 is controlled by an ECU (Electronic Control Unit) and injects fuel into the intake passage part 32 in response to the output of a throttle sensor or the like.

For example, the ECU performs feedback control of the fuel injection amount based on the output of an exhaust gas sensor (O2 sensor) (not shown) to achieve theoretical air-fuel consumption operation.
In this embodiment, by providing the chamber T3 for temporarily storing the mixed fuel, even when a fuel with a different fuel composition is refueled from the fuel immediately before refueling, the fuel before and after refueling are mixed gently. This prevents the fuel supplied to the injector 40 from suddenly changing to a different type of fuel from the fuel immediately before refueling, making it easier to follow the feedback control.
A return path 55 extending from the fuel chamber portion 50 will be described later.

2 and 3, the intake passage parts 32 including the throttle body 33 are disposed so as to be biased to one side (the right side in this embodiment) with respect to the center CL of the vehicle body.
A port opening 37 is provided at the rear of the cylinder head 12b, forming the intake port's opening to the outside of the cylinder (external opening). The front end (downstream end) of an intake pipe member 36 is fixed to the port opening 37. The front end (downstream end) of a throttle body 33 is connected to the rear end (upstream end) of the intake pipe member 36. The front end (downstream end) of a connecting tube 35 is connected to the rear end (upstream end) of the throttle body 33. The intake passage formed by the entire intake passage component 32 is designated by the symbol TA (see FIG. 1).

<Injector>
2, 4 and 5, an injector 40 is attached to the upper front side of the intake pipe member 36.
The injector 40 includes a cylindrical injector body, a valve portion housed in the injector body, and an electromagnetic actuator (none of which are shown) that drives the valve portion. In the drawing, line C1 indicates the central axis of the injector 40, and symbol 40b indicates an injection port provided at one axial end of the injector 40.
The injector body defines a fuel flow path therein for fuel to flow through. The valve portion closes the fuel flow path by the biasing force applied by the return spring, thereby closing the injector 40.
The electromagnetic drive unit drives the valve unit against the biasing force of the return spring to open the fuel flow path and open the injector 40. This causes fuel to be injected from the injection port 40b of the injector 40 into the intake passage TA.

The injector 40 is connected to a fuel chamber 50 that stores fuel to be supplied to the injector 40, and a heater device 60 that heats (raises the temperature of) the fuel in the fuel chamber 50, at an extension portion opposite (upstream of) the injection port 40b in its longitudinal direction (the longitudinal direction of the injector body). The fuel chamber 50 and heater device 60 together constitute a heating section that raises the temperature of the fuel to be supplied to the injector 40.

Referring to Figure 5, the fuel chamber section 50 includes a chamber case 51. The chamber case 51 is cylindrical and opens upstream of the injector 40, forming a chamber T3 as an internal space. Line C2 in the figure indicates the central axis of the fuel chamber section 50. In the example of Figure 5, the fuel chamber section 50 and the injector 40 are arranged coaxially with each other.

A feed nozzle 53 for connecting a feed hose 48 protrudes from the outer peripheral wall 52 of the chamber case 51. The feed hose 48 is included in the fuel feed path 44. The fuel feed path 44 extends from the discharge portion 43 of the fuel pump 42 and enables pressurized fuel to be supplied into the chamber T3 via the feed nozzle 53. The feed nozzle 53 in Figure 5 is located in the axial middle (not necessarily the center) of the outer peripheral wall 52. The end opening 53a (inlet to the fuel chamber 50) on the chamber T3 side of the feed nozzle 53 is located above the center position in the up-down direction (vertical direction) of the fuel chamber 50 (chamber T3).

A return nozzle 54 for connecting a fuel return hose 58 protrudes from the outer wall 52 of the chamber case 51. The return hose 58 is included in the return path 55. The return path 55 extends toward the return section of the fuel tank 15 and allows a portion of the pressurized fuel in the chamber T3 to be discharged from the return nozzle 54. The return nozzle 54 in FIG. 5 is located at the axial lower end of the outer wall 52. The end opening 54a (outlet from the fuel chamber 50) of the return nozzle 54 on the chamber T3 side is located below the vertical center of the fuel chamber 50 (chamber T3). The fuel discharged from the return nozzle 54 is relatively cold within the chamber T3, so a decrease in the temperature of the fuel within the chamber T3 due to the discharge of the fuel is minimized. The inlet 53a is located above the outlet 54a, creating a top-down flow from the inlet 53a toward the outlet 54a.

Discharging a portion of the fuel from the return nozzle 54 promotes agitation by the upward flow of the heated fuel around the heater 62 and the downward flow of the fuel supplied from the feed nozzle 53, and the heated fuel is guided to the lower end side (injector 40 side) of the chamber T3. Agitation of the fuel within the chamber T3 suppresses unevenness in the fuel temperature and improves heat transfer by suppressing the generation of vapor on the surface of the heater 62.
The feed nozzle 53 is not limited to being located in the axially intermediate portion of the outer peripheral wall 52, but may be located closer to the axially upper end of the outer peripheral wall 52. In this case, the vertical flow within the chamber T3 is further promoted.

The upstream end of the injector body is connected to the downstream end of the chamber case 51. A main body (heater main body) 61 of a heater device 60 is attached to the end of the chamber case 51 opposite the injector body.
The heater device 60 has a rod-shaped heater portion 62 that protrudes into the chamber T3 from a heater main body portion 61. The heater portion 62 is disposed coaxially with the chamber case 51, for example.

Fuel supplied from the feed hose 48 is supplied to and stored in the chamber T3, where it is heated by the heat generated by the heater 62. The fuel in the area closer to the heater 62 is in direct contact with the heater 62 and therefore heats up more easily than the fuel in the area farther from the heater 62. The density of the fuel in the area closer to the heater 62 is lower than that of the fuel farther from the heater 62, creating buoyancy and generating an upward flow (natural convection). For ease of explanation, Figure 5 shows an example in which the fuel chamber 50 is arranged with its longitudinal direction (axial direction) aligned vertically.

Fuel that reaches the upper end of chamber T3 in the area surrounding heater 62 turns downward on the outer periphery of chamber T3 and flows downward. Fuel that reaches the lower end on the outer periphery of chamber T3 turns upward on the inner periphery of chamber T3 (towards heater 62) and flows upward again. The flow from feed nozzle 53 to return nozzle 54 further promotes mixing, shortening the heating time required to heat the fuel to the specified temperature.

The fuel heated to a specified temperature reaches the injector body of the injector 40, and is injected into the intake passage TA from the injection port 40b by driving the valve portion.
In the ethanol fuel engine 10, in order to improve cold startability and reduce harmful components contained in the exhaust gas, it is effective to inject heated fuel into the intake passage TA to promote vaporization of the injected fuel.

Here, the operation of the heater device 60 will be described.
When the vehicle is parked and the engine 10 is stopped, the engine 10 is cold, and the fuel in the fuel supply device 40A is also cold. In order to promote vaporization of the fuel injected into the intake passage TA, it is necessary to heat the fuel using the heater device 60 before starting the engine 10. A suitable timing for the heater device 60 to start heating the fuel is, for example, when the main switch of the vehicle is turned on while the engine 10 is stopped and the vehicle is parked and stopped.

The heater device 60 begins heating the fuel, for example, when the heater device 60 is turned on. The heater device 60's control unit activates a timer when the heater device 60 is turned on, and turns the heater device 60 off after a specified time has elapsed. The engine 10 can then be started (starter driven). At this time, an indicator lamp may be turned on to notify the user that the engine can now be started.

The heater-on duration may be varied depending on, for example, the ambient temperature or the engine temperature. Temperature detection can be performed using information detected by, for example, an existing intake air temperature sensor, oil temperature sensor, etc. Alternatively, a temperature sensor may be installed in the fuel chamber 50 to directly detect the temperature of the fuel in the chamber T3. In addition to (or instead of) the heater-on duration, the output of the heater device 60 may be varied.
In this embodiment, the heater is turned off once a predetermined condition is met after the fuel has started to be heated (for example, after a predetermined time has elapsed), but the heater may be kept on to continue heating the fuel while the vehicle is running in order to promote vaporization of the fuel. Note that in this embodiment, the fuel chamber 50 is designed so that it is easily exposed to the heated airflow that flows around the engine 10, which contributes to reducing the amount of electricity consumed when the heater is kept on.

In an ethanol-fueled engine 10, low ambient temperatures tend to lengthen the fuel preheat time. That is, in a configuration in which the heater unit 62 is inserted into the fuel chamber 50 to heat the fuel, it is necessary to wait until a certain flow velocity is reached before agitation by natural convection occurs.
The heater section 62 and the fuel chamber section 50 are arranged with their axial direction (longitudinal direction) oriented vertically, which has the following effect: The fuel in the fuel chamber section 50 is heated in contact with a wide area in the longitudinal direction of the heater section 62 during natural convection, which effectively generates convection within the fuel chamber section 50 and enables preheating without temperature bias.

Depending on the blend ratio of ethanol fuel, the fuel pressure may exceed the target value when heated within the fuel chamber 50. To quickly release this excess pressure, a return path 55 is connected to the fuel chamber 50, as shown in Figure 5.

The return path 55 includes a return nozzle 54 protruding from the outer wall 52 of the chamber case 51, a return hose 58 connected at one end to the return nozzle 54 and at the other end to the fuel tank 15, an orifice 56 located upstream of the return hose 58 (near the return nozzle 54), and a solenoid valve (return control valve) 57 located downstream of the orifice 56 on the return hose 58.

The solenoid valve 57 opens for a predetermined time (e.g., 10 seconds) during engine startup, opening the flow path in the return hose 58. After the predetermined time has elapsed, the solenoid valve 57 closes, blocking the flow path in the return hose 58. The solenoid valve 57 opens only during engine startup, allowing a portion of the pressurized fuel in the chamber T3 to be discharged through the return nozzle 54. This creates a flow of fuel within the chamber T3 during engine startup, promoting uniform heating. The amount of pressurized fuel discharged is controlled by placing an orifice 56 in the return hose 58 to narrow the flow path, preventing a decrease in efficiency due to excessive fuel return. While the solenoid valve 57 operates under a predetermined time in this embodiment, other conditions, such as engine temperature (oil temperature, water temperature, etc.), intake air temperature, O2 sensor readings, throttle opening, and alcohol fuel concentration, may also be used, and a combination of these may also be used.

As described above, the fuel supply device 40A in the above embodiment includes the injector 40 that injects fuel into the intake passage TA of the engine 10, the fuel chamber 50 that is connected to the upstream side of the injector 40 and stores the fuel to be supplied to the injector 40, the heater 62 that is disposed in the fuel chamber 50 and heats the fuel stored in the fuel chamber 50, the fuel tank 15 that stores fuel for the engine 10, the fuel pump 42 that pumps the fuel in the fuel tank 15 to the injector 40, and the heater 62 that heats the fuel stored in the fuel chamber 50. and a pressure regulating means (pressure regulator 46) for regulating the pressure of the fuel entering the fuel chamber 50 to a specified pressure for injection from the injector 40. The fuel chamber 50 is connected to a fuel feed path 44 that sends the fuel whose pressure has been regulated by the pressure regulator 46 into the fuel chamber 50, and a fuel return path 55 that has a throttle section (orifice 56) that throttles the flow path of the fuel feed path 44 and returns the fuel in the fuel chamber 50 to the upstream side of the fuel pump 42 (for example, into the fuel tank 15).
According to this configuration, an orifice 56 that narrows the flow path relative to the fuel feed path 44 is provided in the fuel return path 55, which returns fuel in the fuel chamber 50 to the side upstream of the fuel pump 42. This allows a portion (a small amount) of fuel to be returned from the fuel return path 55 to the upstream side of the fuel pump 42 while maintaining the fuel pressure in the fuel chamber 50. This allows a flow of fuel to be generated in the fuel chamber 50 during preheating without fuel injection from the injector 40. This promotes agitation of the fuel in the fuel chamber 50, allowing for uniform heating and shortening the preheating time before fuel injection. Note that if a return path leading to the suction side (upstream side) of the fuel pump 42 is provided, the fuel in the fuel chamber 50 may be returned to the return path rather than to the fuel tank 15.
The "throttled portion" in this application may be a portion in which the flow path is narrowed, or may be a portion in which the flow path is narrowed (narrowed) over the entire fuel return path compared to the fuel feed path.
The present invention is not limited to engines that inject fuel into the intake passage, but may also be applied to direct injection engines that inject fuel directly into the combustion chamber.

In addition, in the fuel supply device 40A, a return control valve (solenoid valve 57) that opens and closes the flow path of the fuel return path 55 is provided in the fuel return path 55, and the solenoid valve 57 opens the flow path to allow the return of fuel before fuel injection from the injector 40 begins, and closes the flow path to restrict the return of fuel after fuel injection from the injector 40 begins.
According to this configuration, by opening the solenoid valve 57 provided in the fuel return path 55 until fuel injection starts (preheat period), a forced flow of fuel is created in the fuel chamber 50, promoting natural convection of the fuel and shortening the preheat period. After fuel injection starts, the solenoid valve 57 is closed to prevent the heated fuel from leaking, reducing the energy consumption of the heater device 60 and enabling efficient fuel heating.

Second Embodiment
Next, a second embodiment of the present invention will be described with reference to FIG.
The second embodiment differs from the first embodiment in that it includes a fuel return path 55'. The fuel return path 55' includes a second pressure regulating means (a pressure regulating valve, a second pressure regulator 56') instead of the orifice 56 and the solenoid valve 57. Other components that are the same as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

The second pressure regulator 56' opens when the fuel pressure in the fuel chamber 50 exceeds a predetermined pressure, allowing the fuel pressure in the fuel chamber 50 to flow through the fuel return path 55'. This fuel is returned to the fuel tank 15 (upstream of the fuel pump 42) via a return flow path (not shown). The opening pressure of the second pressure regulator 56' is higher than the opening pressure of the pressure regulator 46 in the fuel feed path 44. Therefore, as long as the fuel pressure in the fuel chamber 50 is within the appropriate pressure range adjusted by the pressure regulator 46, the second pressure regulator 56' will not open the fuel return path 55'.

The return nozzle 54' in the second embodiment is located at the axially upper end of the outer peripheral wall 52. The end opening 54a' (outlet from the fuel chamber section 50) on the chamber T3 side of the return nozzle 54' is located at the top of the fuel chamber section 50 (chamber section T3) in the up-down direction (vertical direction). This allows for efficient discharge of fuel vapor generated within the fuel chamber section 50 and accumulated at the top. The inlet 53a of the feed nozzle 53 is offset axially downward from the outlet 54a' of the return nozzle 54', making it less likely that the fuel flowing in from the feed nozzle 53 and the fuel discharged from the return nozzle 54' will affect each other.

As described above, the fuel supply device 40A in the second embodiment includes the injector 40 that injects fuel into the intake passage TA of the engine 10, the fuel chamber portion 50 that is connected upstream of the injector 40 and that stores the fuel to be supplied to the injector 40, the heater portion 62 that is disposed within the fuel chamber portion 50 and that heats the fuel stored within the fuel chamber portion 50, the fuel tank 15 that stores fuel for the engine 10, the fuel pump 42 that pressure-feeds fuel in the fuel tank 15 to the injector 40, and a pressure regulating means (pressure regulator 46) that adjusts the pressure of the fuel pressure-feed by the fuel pump 42 to a specified pressure for injection from the injector 40. A fuel feed path 44 that sends the fuel whose pressure is adjusted by the pressure regulator 46 into the fuel chamber 50, and a fuel return path 55′ that returns the fuel in the fuel chamber 50 to a side upstream of the fuel pump 42 are connected to the fuel chamber 50. The fuel feed path 44 is provided with a check valve 45 that allows the flow of fuel toward the fuel chamber 50 and regulates the flow of fuel toward the fuel pump 42. The fuel return path 55′ is provided with a pressure adjusting valve (second pressure regulator 56′) that does not open until the pressure of the fuel in the fuel chamber 50 reaches a second specified pressure that is higher than the specified pressure, and opens when the pressure exceeds the second specified pressure.
are.
According to this configuration, the fuel feed path 44, which sends pressure-regulated fuel to the fuel chamber 50, is provided with a check valve 45, and the fuel return path 55', which returns fuel in the fuel chamber 50 to a side upstream of the fuel pump 42, is provided with a second pressure regulator 56' that opens when a fuel pressure higher than that of the fuel feed path 44 is applied. This allows a portion (a small amount) of high-pressure fuel to be returned to the upstream side of the fuel pump 42 through the fuel return path 55' while maintaining the fuel pressure in the fuel chamber 50. As a result, even if an unintended pressure increase occurs during fuel preheating, excess pressure can be released through the fuel return path 55'. This allows the allowable pressure of the fuel hose, the injector 40, and the like to be set appropriately without unnecessarily increasing, thereby suppressing increases in component costs.

As a modification of each of the above embodiments, a fuel stirring device for stirring the fuel in the chamber T3 can be provided, as in the fuel chamber 150 shown in Figure 7. The fuel stirring device includes, for example, an axial fan 150a disposed in the chamber T3, and a drive source 150b such as an electric motor that drives the axial fan 150a. In the example shown in Figure 7, the fuel stirring device is disposed at the bottom of the fuel chamber 150, so the axial directions of the fuel chamber 150 and the injector 40 are different from each other.

Drive source 150b is driven, for example, by a control device (not shown) only during engine startup and when the fuel temperature is low, to agitate the fuel in chamber T3. The fuel agitation device may be a manual type that does not have drive source 150b and instead operates a fan or the like via manual input from the user. This modification effectively agitates the fuel in fuel chamber 50, allowing preheating without causing temperature imbalance. Therefore, the temperature of the fuel before being supplied to injector 40 can reach the target temperature (e.g., 100°C or higher) in a short time. Faster fuel warming improves the cold startability of the ethanol-fueled engine 10 and shortens the start time. Promoting fuel vaporization improves fuel economy and heat exchange efficiency.

The present invention is not limited to the above-described embodiment. For example, the fuel supply device of the present embodiment may be applied to a saddle-ride type vehicle other than a motorcycle.
The saddle-ride type vehicle includes all vehicles on which a driver straddles the vehicle body, and includes not only motorcycles (including motorized bicycles and scooter-type vehicles) but also three-wheeled vehicles (including vehicles with one front wheel and two rear wheels, as well as vehicles with two front wheels and one rear wheel) or four-wheeled vehicles (such as four-wheeled buggies). The invention may also be applied to vehicles that include an electric motor as a prime mover, such as HEVs (Hybrid Electric Vehicles). The invention may also be applied to vehicles other than saddle-ride type vehicles (such as passenger cars, buses, and trucks). That is, although the vehicle in the embodiment is a flexible fuel motorcycle (FFM), it may also be a four-wheeled vehicle (flexible fuel vehicle (FFV)).
Although the fuel supply device of this embodiment is applied to a vehicle, the present invention is not limited to application to vehicles and may be applied to various vehicles and moving objects such as various transportation equipment such as aircraft and ships, as well as construction machinery and industrial machinery. Furthermore, the present invention can be widely applied to equipment other than vehicles that has a fuel supply device, such as push lawn mowers and cleaning machines.
The configurations in the above-described embodiments are merely examples of the present invention, and various modifications are possible within the scope of the gist of the present invention, such as replacing the components of the embodiments with well-known components.

1. Motorcycles (saddle-type vehicles)
10. Engine (internal combustion engine)
15 Fuel tank 32 Intake passage part 40 Injector 40A Fuel supply device 42 Fuel pump 44 Fuel feed path 45 Check valve 46 Pressure regulator (pressure adjusting means)
50 Fuel chamber portion 53a Inlet 54a, 54a' Outlet 55, 55' Fuel return path 56 Orifice (throttling portion)
56' Second pressure regulator (pressure adjusting valve)
57 Solenoid valve (return control valve)
61 heater main body 62 heater section TA intake passage

Claims (5)

an injector (40) that supplies fuel to be burned in a combustion chamber of an internal combustion engine (10) and has a valve portion driven by an electromagnetic drive portion ;
a fuel chamber portion (50) connected to the upstream side of the injector (40) and storing fuel to be supplied to the injector (40);
a heater section (62) disposed within the fuel chamber section (50) for heating the fuel stored within the fuel chamber section (50);
a fuel tank (15) for storing fuel for the internal combustion engine (10);
a fuel pump (42) that pumps fuel in the fuel tank (15) to the injector (40);
a pressure adjusting means (46) for adjusting the pressure of the fuel pumped by the fuel pump (42) to a specified pressure for injection from the injector (40);
a fuel feed path (44) connected to the fuel chamber portion (50) and sending fuel whose pressure has been adjusted by the pressure adjusting means (46) into the fuel chamber portion (50),
The fuel chamber portion (50) includes:
a throttle section (56) that throttles the flow path of the fuel feed path (44), and a fuel return path (55) that returns the fuel in the fuel chamber section (50) to a side upstream of the fuel pump (42) is connected to the fuel feed path (44);
The fuel chamber portion (50) is connected to the opposite side of the injection port (40b) of the injector (40) and is disposed above the injector (40).
The fuel return path (55) is connected to the fuel chamber portion (50),
A return control valve (57) is provided in the fuel return path (55) to open and close the flow path of the fuel return path (55),
The return control valve (57) opens the flow path to allow the return of fuel before fuel injection from the injector (40) starts, and closes the flow path to restrict the return of fuel after fuel injection from the injector (40) starts. The fuel chamber portion (50) has an outlet (54a) to the fuel return path (55),
2. The fuel supply device according to claim 1, wherein the outlet (54a) is disposed below the center of the fuel chamber portion (50) in the vertical direction. The fuel chamber portion (50) has an outlet (54a) to the fuel return path (55) and an inlet (53a) from the fuel feed path (44),
The fuel supply device according to claim 1 or 2, wherein the inlet (53a) is disposed above the outlet (54a). an injector (40) for supplying fuel for combustion in a combustion chamber of an internal combustion engine (10);
a fuel chamber portion (50) connected to the upstream side of the injectors (40), storing fuel to be supplied to the injectors (40), and disposed coaxially with one of the injectors (40);
a heater section (62) disposed within the fuel chamber section (50) for heating the fuel stored within the fuel chamber section (50);
a fuel tank (15) for storing fuel for the internal combustion engine (10);
a fuel pump (42) that pumps fuel in the fuel tank (15) to the injector (40);
a pressure adjusting means (46) for adjusting the pressure of the fuel pumped by the fuel pump (42) to a specified pressure for injection from the injector (40);
a fuel feed path (44) connected to the fuel chamber portion (50) and sending fuel whose pressure has been adjusted by the pressure adjusting means (46) into the fuel chamber portion (50),
The fuel chamber portion (50) includes:
a fuel return path (55') that returns the fuel in the fuel chamber portion (50) to a side upstream of the fuel pump (42);
The fuel feed path (44) is provided with a check valve (45) that allows fuel to flow toward the fuel chamber portion (50) and restricts fuel flow toward the fuel pump (42),
The fuel return path (55') is provided with a pressure regulating valve (56') that does not open until the pressure of the fuel in the fuel chamber portion (50) reaches a second specified pressure that is higher than the specified pressure, and that opens when the pressure exceeds the second specified pressure,
The fuel chamber portion (50) is connected to the opposite side of the injection port (40b) of the injector (40) and is disposed above the injector (40).
The fuel return path (55') is connected to the fuel chamber portion (50). The fuel chamber portion (50) has an outlet (54a') to the fuel return path (55'),
5. The fuel supply device of claim 4, wherein the outlet (54a') is located at the top of the fuel chamber portion (50).