Fuel supply device

Abstract

To promptly heat fuel in a fuel chamber part in a fuel supply device that heats fuel to be supplied to an injector.SOLUTION: A fuel supply device includes a fuel chamber part 50 that is connected to an upstream side of an injector 40 and that stores fuel to be supplied to the injector 40. A fuel feed passage 44 for feeding fuel having pressure controlled by a pressure regulator 46 into the fuel chamber part 50 and a fuel return passage 55 in which an orifice 56 with a flow passage narrowed relative to the fuel feed passage 44 is set and that returns the fuel in the fuel chamber part 50 to an upstream side of a fuel pump 42 are connected to the fuel chamber part 50.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a fuel supply system. [Background technology]

[0002] 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. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 4834728 Summary of the Invention [Problem to be solved by the invention]

[0004] When applying the above-mentioned conventional technology to reduce carbon dioxide emissions, it is more convenient to shorten the time from when the heater starts heating until the fuel accumulated upstream of the injector is fully heated. However, in systems where pre-pressurized fuel is supplied to a fuel chamber in which a heater is located, a return pipe for returning the fuel in the chamber to the fuel tank (upstream of the pump) is generally not provided. In particular, during pre-heating before engine start, fuel injection has not yet started, so there is no active fuel flow and it is necessary to rely only on natural convection, making it difficult to uniformly heat the fuel in the fuel chamber.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to quickly heat the fuel in the fuel chamber in a fuel supply device that heats the fuel to be supplied to an injector. [Means for solving the problem]

[0006] 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 (50) that is connected upstream of the injector (40) and stores the fuel to be supplied to the injector (40), a heater (62) that is disposed in the fuel chamber (50) and heats 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), and a heater (62) that heats the fuel stored in the fuel chamber (50). 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.

[0007] 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 the start of fuel injection from the injector (40), and closes the flow path to restrict the return of fuel after the start of fuel injection from the injector (40). 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, the return control valve is closed to prevent the heated fuel from leaking, reducing the energy consumption of the heater device and enabling efficient fuel heating.

[0008] 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.

[0009] 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.

[0010] A fifth 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) connected upstream of the injector (40) and storing the fuel to be supplied to the injector (40), a heater section (62) disposed within the fuel chamber section (50) and heating 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 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 section (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 into the fuel chamber portion (50) with its pressure adjusted by a pressure adjusting valve (6). A fuel return path (55') that returns the fuel in the fuel chamber portion (50) to a side upstream of the fuel pump (42) is connected to the fuel chamber portion (50). 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 restricts the flow of fuel toward the fuel pump (42). 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.

[0011] 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 directed into the fuel return path, resulting in quick pressure reduction. [Effects of the Invention]

[0012] 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 heated quickly. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a right side view of a motorcycle according to an embodiment of the present invention. [Figure 2] FIG. 2 is an enlarged view of a main part of FIG. [Figure 3] FIG. 2 is a top view of the vicinity of an intake passage part of the motorcycle. [Figure 4] FIG. 2 is a configuration diagram of a fuel supply device of the motorcycle. [Figure 5] 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. [Figure 6] 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. [Figure 7] 10 is an explanatory diagram showing a modified example of the fuel chamber portion. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, directions such as front, rear, left, and right are the same as directions in the vehicle described below unless otherwise specified. In addition, in the drawings used in the following description, an arrow FR indicating the front of the vehicle, an arrow LH indicating the left side of the vehicle, an arrow UP indicating the top of the vehicle, and a line CL indicating the center of the vehicle body to the left and right are shown in appropriate positions.

[0015] <Entire vehicle> As shown in Fig. 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.

[0016] The rear wheel 7 of the motorcycle 1 is supported at the rear end of a swing arm 8. The front end of the swing arm 8 is supported by a pivot frame 23 located at the midpoint between the front and rear of the body frame 20. Note that the term "midpoint" used in this embodiment refers not only to the center between both ends of an object, but also to the inner range between both 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.

[0017] 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 and change the speed of the output of the engine 10, and is fixedly supported on the body frame 20. The engine 10 has a cylinder 12 standing 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, for example, to the right rear, and is connected to an exhaust muffler 14a located on the right rear of the vehicle body.

[0018] A fuel tank 15 that stores fuel to be supplied to the engine 10 is disposed above the engine 10. A seat 16 on which the driver and a passenger sit is disposed behind the fuel tank 15. A pair of left and right main steps 17 on which the driver places his / her feet, and a pair of left and right pillion steps 18 on which the passenger places his / her feet are disposed on both sides of the lower body of the vehicle.

[0019] 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 in the vertical direction to support the seat rails 25.

[0020] The engine 10 can be operated using not only gasoline but also ethanol or a blend of gasoline and ethanol (hereinafter collectively referred to as ethanol fuel). 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.

[0021] 2, the downstream end of an intake passage part 32 including a throttle body 33 is connected to the rear part (intake side) of the cylinder head 12b. In the figure, reference numeral 34 denotes an air cleaner box to which the upstream end of the intake passage part 32 is connected, reference numeral 35 denotes a connecting tube that connects the throttle body 33 and the air cleaner box 34, and reference numeral 36 denotes an intake pipe member that connects 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 part 32.

[0022] <Fuel supply device> As shown in FIG. 4, motorcycle 1 includes fuel tank 15, fuel pump 42, injector (fuel injection valve) 40, and the like, which constitutes a fuel supply device 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 out 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).

[0023] 5, a 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 a pressure adjusting 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 reverse 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 or the like. Therefore, when the engine 10 is restarted, the fuel can be pressurized to the pressure required for fuel injection with little pump drive.

[0024] 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 into the fuel tank 15 via a return flow path 47. The fuel whose pressure has been 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. Although the check valve 45 and the pressure regulator 46 are shown as separate from the fuel pump 42 in FIG. 5 , at least one of the check valve 45 and the pressure regulator 46 may be integrated with the fuel pump 42. As a pressure adjusting means instead of the pressure regulator 46, a configuration in which the pressure of the fuel is adjusted by driving control (for example, rotation speed control) of the fuel pump 42 may also be used.

[0025] 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.

[0026] 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 a chamber T3 for temporarily storing the mixed fuel, even when a fuel with a different fuel composition is refueled, 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 before refueling, making it easier to follow the feedback control. A return path 55 extending from the fuel chamber portion 50 will be described below.

[0027] 2 and 3, the intake passage part 32 including the throttle body 33 is disposed so as to be biased to one side (the right side in this embodiment) with respect to the vehicle body left-right center CL. A port opening 37 is provided at the rear of the cylinder head 12b, forming an opening (external opening) of the intake port to the outside of the cylinder. 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 part 32 is designated by the symbol TA (see FIG. 1).

[0028] <Injector> 2, 4 and 5, an injector 40 is attached to the upper front side of the intake pipe member . The injector 40 includes a cylindrical injector body, a valve portion housed in the injector body, and an electromagnetic drive portion (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 through which fuel flows. The valve portion closes the fuel flow path by the biasing force of 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.

[0029] A fuel chamber 50 that stores fuel to be supplied to the injector 40 and a heater device 60 that heats (increases the temperature of) the fuel in the fuel chamber 50 are connected to an extension portion of the injector 40 on the opposite side (upstream side) from the injection port 40b in its longitudinal direction (longitudinal direction of the injector body). The fuel chamber 50 and the heater device 60 form a temperature increasing portion that increases the temperature of the fuel to be supplied to the injector 40.

[0030] 5, the fuel chamber 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 50. In the example of FIG. 5, the fuel chamber 50 and the injector 40 are arranged coaxially with each other.

[0031] 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 FIG. 5 is disposed in the axial middle portion (not necessarily the center) of the outer peripheral wall 52. An end opening 53a (inlet to the fuel chamber 50) on the chamber T3 side of the feed nozzle 53 is disposed above the center position in the up-down direction (vertical direction) of the fuel chamber 50 (chamber T3).

[0032] A return nozzle 54 for connecting a fuel return hose 58 protrudes from the outer peripheral wall 52 of the chamber case 51. The return hose 58 is included in a return path 55. The return path 55 extends toward the return portion 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 disposed at the axial lower end of the outer peripheral wall 52. An end opening 54a (outlet from the fuel chamber 50) of the return nozzle 54 on the chamber T3 side is disposed below the center position of the fuel chamber 50 (chamber T3) in the up-down direction (vertical direction). The fuel discharged from the return nozzle 54 is relatively low-temperature fuel in the chamber T3, so a decrease in the temperature of the fuel in the chamber T3 due to the discharge of the fuel is suppressed. The inlet 53a is disposed above the outlet 54a, thereby forming a downward flow from the inlet 53a toward the outlet 54a.

[0033] Discharging a portion of the fuel from the return nozzle 54 promotes agitation by the upward flow of the heated fuel around the heater section 62 and the downward flow of the fuel supplied from the feed nozzle 53, and the heated fuel is led to the lower end side (injector 40 side) of the chamber T3. Agitation of the fuel in the chamber T3 suppresses unevenness in the fuel temperature and also suppresses the generation of vapor on the surface of the heater section 62, improving heat transfer. The feed nozzle 53 is not limited to being located in the axial middle portion of the outer peripheral wall 52, but may be located closer to the axial upper end of the outer peripheral wall 52. In this case, the vertical flow within the chamber T3 is further promoted.

[0034] 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 the heater device 60 is attached to the end of the chamber case 51 opposite to 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.

[0035] 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, which generates buoyancy and generates an upward flow (natural convection). For ease of explanation, FIG. 5 shows an example in which the fuel chamber 50 is arranged with its longitudinal direction (axial direction) aligned vertically.

[0036] The fuel that reaches the upper end of the chamber T3 in the area around the heater 62 turns downward at the outer periphery of the chamber T3 and flows downward. The fuel that reaches the lower end of the chamber T3 at the outer periphery turns upward at the inner periphery of the chamber T3 (the heater 62 side) and flows upward again. The flow from the feed nozzle 53 to the return nozzle 54 adds to this, further promoting mixing and shortening the heating time required to heat the fuel to a specified temperature.

[0037] 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.

[0038] 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 evaporation of the fuel to be 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.

[0039] Heating of the fuel by the heater device 60 starts, for example, when the heater device 60 is turned on. The control unit of the heater device 60 activates a timer when the heater device 60 is turned on, and turns off the heater device 60 after a specified time has elapsed. Thereafter, starting of the engine 10 (starter driving) becomes possible. At this time, an indicator lamp may be turned on to notify the user that the engine can now be started.

[0040] The duration for which the heater is on may be varied depending on, for example, the outside air temperature or the engine temperature. The 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 can 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 duration for which the heater is on, 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, the passage of a predetermined time), 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 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.

[0041] 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 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 natural convection stirring 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.

[0042] Depending on the blend ratio of ethanol fuel, the pressure of the fuel may exceed the target value when heated in the fuel chamber 50. To quickly release this excess pressure, a return path 55 is connected to the fuel chamber 50, as shown in FIG.

[0043] The return path 55 includes a return nozzle 54 protruding from the outer peripheral wall 52 of the chamber case 51, a return hose 58 having one end connected to the return nozzle 54 and the other end connected to the fuel tank 15, an orifice 56 arranged upstream of the return hose 58 (near the return nozzle 54), and a solenoid valve (return control valve) 57 arranged downstream of the orifice 56 on the return hose 58.

[0044] 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 allows the fuel in the chamber T3 to flow 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. Note that, although the predetermined time is used as the activation condition for the solenoid valve 57 in this embodiment, other conditions such as engine temperature (oil temperature, water temperature, etc.), intake temperature, O2 sensor value, throttle opening, and alcohol fuel concentration may also be used, and a combination of these may also be used.

[0045] 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 portion 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 portion 62 that is disposed in the fuel chamber portion 50 and heats the fuel stored in the fuel chamber portion 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 portion 62 that heats the fuel stored in the fuel chamber portion 50. and a pressure adjusting means (pressure regulator 46) that adjusts the pressure of the fuel 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 adjusted 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 shortens 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 partially throttled, or may be a portion in which the flow path is throttled (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.

[0046] 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 set 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, solenoid valve 57 provided in fuel return path 55 is opened until fuel injection starts (preheat period), thereby forcing a flow of fuel in fuel chamber 50 and promoting natural convection of the fuel, thereby shortening the preheat period. After fuel injection starts, solenoid valve 57 is closed to prevent the heated fuel from leaking, reducing the energy consumption of heater device 60 and enabling efficient fuel heating.

[0047] 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.

[0048] The second pressure regulator 56' opens when the pressure of the fuel in the fuel chamber 50 exceeds a predetermined pressure, and causes the pressure of the fuel in the fuel chamber 50 to flow to the fuel return path 55'. This fuel is returned to the fuel tank 15 (upstream of the fuel pump 42) via a return path (not shown). The valve opening pressure of the second pressure regulator 56' is higher than the valve opening pressure of the pressure regulator 46 of the fuel feed path 44. Therefore, as long as the pressure of the fuel 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'.

[0049] The return nozzle 54' of the second embodiment is disposed at the axial upper end of the outer peripheral wall 52. An end opening 54a' (outlet from the fuel chamber 50) on the chamber T3 side of the return nozzle 54' is disposed at the top in the up-down direction (vertical direction) of the fuel chamber 50 (chamber T3). This allows fuel vapor generated in the fuel chamber 50 and accumulated at the top to be efficiently discharged. The inlet 53a of the feed nozzle 53 is shifted axially downward from the outlet 54a' of the return nozzle 54', making it difficult for the fuel flowing in from the feed nozzle 53 and the fuel discharged from the return nozzle 54' to affect each other.

[0050] 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 in 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. The fuel chamber 50 is connected to a fuel feed path 44 that sends the fuel whose pressure has been 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. The fuel feed path 44 is provided with a check valve 45 that allows the flow of fuel toward the fuel chamber 50 and restricts 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 the check valve 45, and the fuel return path 55', which returns the fuel in the fuel chamber 50 to the upstream side of the fuel pump 42, is provided with the second pressure regulator 56', which opens when the fuel pressure is higher than that of the fuel feed path 44. This makes it possible to return a portion (a small amount) of high-pressure fuel to the upstream side of the fuel pump 42 through the fuel return path 55' while maintaining the pressure of the fuel in the fuel chamber 50. As a result, even if an unintended pressure increase occurs during fuel preheating, the 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.

[0051] As a modification of each of the above embodiments, a fuel agitation device for agitating the fuel in the chamber T3 may be provided, as in the fuel chamber 150 shown in Fig. 7. The fuel agitation device includes, for example, an axial fan 150a disposed in the chamber T3 and a drive source 150b such as an electric motor for driving the axial fan 150a. In the example shown in Fig. 7, the fuel agitation device is disposed at the bottom of the fuel chamber 150, so that the axial directions of the fuel chamber 150 and the injector 40 are different from each other.

[0052] The 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 the chamber T3. The fuel agitation device may be a manual type, for example, without the drive source 150b, in which a fan or the like is driven manually by a user. This modification effectively agitates the fuel in the fuel chamber 50, allowing preheating without causing unevenness in the fuel temperature. Therefore, the temperature of the fuel before being supplied to the injector 40 can reach a target temperature (e.g., 100°C or higher) in a short time. By warming the fuel more quickly, the cold startability of the ethanol-fueled engine 10 can be improved, shortening the start time. Promoting fuel vaporization can improve fuel economy and heat exchange efficiency.

[0053] 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, including 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). It may also be applied to vehicles that include an electric motor as a prime mover, such as HEVs (Hybrid Electric Vehicles). It may also be applied to vehicles other than saddle-ride type vehicles (such as passenger cars, buses, and trucks). In other words, 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. [Explanation of symbols]

[0054] 1. Motorcycles (saddle-type vehicles) 10 Engine (internal combustion engine) 15 Fuel Tank 32 Intake passage parts 40 injectors 40A fuel supply system 42 Fuel pump 44 Fuel feed path 45 Check valve 46 Pressure regulator (pressure regulation means) 50 Fuel chamber section 53a Inlet 54a, 54a' Outlet 55,55' fuel return path 56 Orifice (throttling part) 56' Second pressure regulator (pressure adjusting valve) 57 Solenoid valve (return control valve) 61 Heater body 62 Heater section TA intake passage

Claims

1. 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) that opens and closes the flow path of the fuel return path (55) is provided in 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.

2. 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.

3. 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).

4. 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).

5. The fuel chamber portion (50) has an outlet (54a') to the fuel return path (55'), 5. The fuel supply device according to claim 4, wherein the outlet (54a') is located at the top of the fuel chamber portion (50).

Images