JP2010265868A - Fuel heating device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To realize, in an internal combustion engine using alcohol-containing fuel, a device which heats the fuel at the time of low-temperature start-up without making a structure or a system complicated. <P>SOLUTION: A delivery pipe 1 which serves as a passage for supplying alcohol-containing fuel stored in a fuel tank T is connected to an injector I for fuel injection via fuel heating pipes 2a, 2b each of which has a flattened tubular form and a prescribed volumetric capacity and is disposed adjacent to the injector I. On a flattened surface of the fuel heating pipes 2a, 2b, connecting pipes 1a, 1b, each of which serves as a connecting part of the injector I and the delivery pipe 1, and attaching pipes 21a, 21b, 22a, 22b, and connecting pipes 1a, 1b are disposed. Centering on those components, a volute-formed induction heating coil 5 is disposed so as to supply a high-frequency electric current from a high-frequency power source and heat the fuel through induction heating. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel heating apparatus that is used in an internal combustion engine that uses an alcohol-containing fuel, and that is particularly effective for a low-temperature starting system that heats a fuel with a high alcohol content and supplies the fuel to an injection device. .

  In recent years, alcohol-containing fuel has attracted attention as an alternative fuel for petroleum. Alcohols such as ethanol have fuel characteristics that are very different from gasoline, so when using a mixed fuel that is a mixture of alcohol fuel and gasoline, especially alcohol-based fuel, control suitable for the fuel properties To improve the engine operating efficiency.

  One of the problems of an engine using an alcohol-containing fuel is improvement of startability in a low temperature environment. Since alcohol fuel has fewer low-boiling components than gasoline, it is difficult to atomize when the engine is not warmed up. For this reason, there has been a problem that it takes a long time to start up in use in an extremely cold region.

  Therefore, in Patent Document 1, fuel heating means is provided in the path for supplying the alcohol-containing fuel, and the heating means is operated according to the state of the engine, and control is performed to increase the operation frequency as the alcohol concentration is higher. It is disclosed. The heating means is, for example, a cylindrical PTC heater fitted at the tip of the injector, and the electric power supplied from the power source is controlled to a predetermined current value according to the alcohol concentration by the energization amount adjusting means, and the operation control means When the PTC heater is energized with an instruction signal from, the fuel injected from the injector is heated.

  Further, in Patent Document 2, a heater is disposed in a fuel passage from a fuel tank filled with light fuel or heavy fuel to an injector for the purpose of improving startability of an engine whose fuel properties are not constant. A fuel injection device with a heater for turning on and off a heater according to a fuel property detected as an internal fuel pressure is disclosed. The heater is an electric heater composed of a heating wire, a nichrome wire, a ribbon heater or the like, and is disposed so as to surround the fuel passage leading to the delivery pipe, and heats the fuel flowing through the fuel passage.

Japanese Patent Laid-Open No. 5-209579 JP-A-7-77130

  Since the apparatus of Patent Document 1 has a structure in which a PTC heater is incorporated in an injector, in a multi-cylinder engine, a heater is installed for each injector and connected to a power source to control the operation and energization amount of each heater. . Further, in order to raise the temperature to a predetermined temperature while the fuel passes through the injector, it is necessary to input a large amount of power and keep the PTC surface temperature at a high temperature. When the PTC surface temperature is kept high, nucleate boiling occurs locally and the heat transfer efficiency is greatly reduced. In order to solve this, it is necessary to preheat the heater before fuel injection, or to maintain the heater at a constant temperature even during injection during which fuel does not pass, which is inefficient.

  On the other hand, in the apparatus of Patent Document 2, since the heater is installed upstream of the delivery pipe, it takes time until the heated fuel is injected until it reaches the injector, so the start-up time becomes long. Further, since the fuel heated by the heater is cooled while being supplied to the injector through the delivery pipe, a high-power heater in consideration of the cooling amount is required. When the heater is operated with high power and the fuel is heated, the fuel may be carbonized to cause an injector seal failure.

  Further, the fuel in the fuel passage downstream from the heater at the time of starting is injected without being heated, and when it can be started, the fuel remaining in the combustion chamber without being burned is discharged into the atmosphere. . Further, since the fuel remaining in the combustion chamber without being burned evaporates as the temperature of the combustion chamber rises, the air-fuel ratio control after the start cannot be performed, which may cause an increase in exhaust emission and a start failure.

  Accordingly, an object of the present invention is to realize an apparatus for heating fuel at the time of cold start in an internal combustion engine using an alcohol-containing fuel without complicating the structure and system. It is another object of the present invention to provide a fuel heating apparatus for an internal combustion engine, which can reduce the start-up time and reduce the exhaust emission with a relatively small and low-power apparatus, and which is highly economical and reliable.

  The invention of claim 1 of the present application is a fuel heating device attached to a fuel injection device of an internal combustion engine, comprising a delivery pipe serving as a supply path for an alcohol-containing fuel stored in a fuel tank, and an injector for fuel injection. A tubular portion serving as a connecting portion between the injector and the delivery pipe is connected to the flat surface of the fuel heating pipe through a fuel heating pipe having a flat tube shape with a predetermined volume arranged close to the injector. In addition, the induction heating coil is disposed in a spiral shape around the tubular portion at least on the flat surface around the tubular portion, and a high frequency power source is connected to the induction heating coil. .

  In the invention of claim 2 of the present application, the fuel heating pipe includes the induction heating coil disposed around the tubular portion on a flat surface facing the tubular portion to which the injector or the delivery pipe is connected. The induction heating coil is arranged in a substantially symmetrical spiral shape.

  In the invention of claim 3, the induction heating coil disposed on the flat surface around the tubular portion and the induction heating coil disposed on the flat surface facing the tubular portion flow. The winding direction of the coil is set so that the current directions are the same.

  In the invention of claim 4 of the present application, it has a plurality of the induction heating coils disposed adjacent to the same flat surface of the fuel heating pipe, and the plurality of the induction heating coils are adjacent outermost coils. The winding direction of the coil is set so that the directions of the currents flowing through are the same.

  In the invention of claim 5, the fuel heating pipe is made of a magnetic material, and an insulating layer is formed on the outer surface thereof.

  In the invention of claim 6 of the present application, the temperature detecting means for directly or indirectly detecting the fuel temperature in the fuel heating pipe, and the high frequency power source is supplied to the induction heating coil based on the detection result of the temperature detecting means. Control means for controlling the high-frequency current is provided.

  In the invention of claim 7, the tubular portion is formed of a magnetic material, and an insulating layer is formed on the outer peripheral surface of the tubular portion, and an induction heating coil surrounding the surface is provided. Yes.

  In the invention of claim 8, the induction heating coil disposed on the flat surface of the fuel heating pipe and the outer peripheral surface of the tubular portion is constituted by a continuous continuous coil.

  In the invention of claim 9 of the present application, a plurality of the tubular portions connected to the plurality of injectors are provided on one of the opposing flat surfaces of the fuel heating pipe, and the other flat surface is connected to the delivery pipe. The tubular portion is provided so that the distances from the plurality of tubular portions connected to the injector are substantially equal.

  In the first aspect of the present invention, when a high-frequency current is supplied from a high-frequency power source to an induction heating coil installed in a flat fuel heating pipe, a magnetic field is generated and the entire fuel heating pipe generates heat. This heat heats the fuel flowing through the inside, and in particular, the temperature of the tubular portion where the magnetic field is concentrated increases, so that the fuel flowing into the injector can be effectively heated. Therefore, the alcohol-containing fuel is efficiently heated at the time of low-temperature start, and quick start can be performed with a relatively small and low-power device.

  According to the second aspect of the present invention, the induction heating coil is disposed around the tubular portion and on the flat surface facing the tubular portion, thereby generating a magnetic field more effectively. Thereby, the heat required for a small apparatus can be efficiently generated and the fuel flowing into the fuel heating pipe can be heated in a short time.

  According to the invention of claim 3 of the present application, the induction heating coil is provided at the opposing position of the opposing flat surfaces so that the current flows in the same direction, so that the generated magnetic field is strengthened and the heating efficiency is further improved. can get.

  According to the invention of claim 4 of the present application, when a plurality of induction heating coils are arranged adjacent to each other, the current flows in the same direction to the adjacent outermost coil, so that the generated magnetic field is strengthened. The effect of further improving the heating efficiency can be obtained.

  According to the invention of claim 5, the fuel heating pipe is made of a magnetic material having a high magnetic permeability, and an insulating layer is formed on the outer surface thereof to maintain a predetermined clearance from the induction heating coil. An induced current can flow.

  According to the sixth aspect of the present invention, the high-frequency power source is controlled based on the fuel temperature in the fuel heating pipe detected by the temperature detecting means, and the high-frequency current is supplied to the induction heating coil, so that the fuel is kept at a predetermined temperature. The heating can be controlled.

  According to the seventh aspect of the present invention, the fuel can be further effectively heated by forming the tubular portion with a magnetic material and disposing the induction heating coil via the insulating layer.

  According to the invention of claim 8 of the present application, the induction heating coil is installed as a continuous coil on the flat surface of the fuel heating pipe and the outer peripheral surface of the tubular portion, whereby high-frequency current can be efficiently supplied. it can.

  According to the ninth aspect of the present invention, the alcohol-containing fuel can be evenly heated and supplied from the tubular portion connected to the delivery pipe to the plurality of tubular portions connected to the plurality of injectors.

BRIEF DESCRIPTION OF THE DRAWINGS It is 1st Embodiment of this invention, (a) is the schematic which shows the principal part structure of a fuel heating apparatus, and is II sectional view taken on the line of (b), (b) is principal part cross section of a fuel heating apparatus. FIG. It is the schematic which shows the fuel-injection apparatus structure of the internal combustion engine which attached the fuel heating apparatus of this invention. It is 2nd Embodiment of this invention, (a) is principal part schematic of fuel heating apparatus, II-II sectional view taken on the line of (b), (b) is principal part sectional drawing of a fuel heating apparatus. . FIG. 5 is a schematic cross-sectional view showing a main part configuration of a fuel heating device according to a third embodiment of the present invention. It is 4th Embodiment of this invention, (a) is the schematic which shows the principal part structure of a fuel heating apparatus, (c) Ia-Ia sectional view taken on the line, (b) is a principal part structure of a fuel heating apparatus. FIG. 2 is a schematic cross-sectional view showing a cross section taken along line Ib-Ib in FIG. 2C, and FIG. It is 5th Embodiment of this invention, (a) is the schematic which shows the principal part structure of a fuel heating apparatus, (c) Ia-Ia sectional view of a line, (b) is principal part structure of a fuel heating apparatus. FIG. 2 is a schematic cross-sectional view showing a cross section taken along line Ib-Ib in FIG. 2C, and FIG. It is a figure for demonstrating the action | operation of this invention, and is a flowchart which shows the control content performed by ECU of an internal combustion engine. It is a figure for demonstrating the action | operation of this invention, and is a flowchart which shows the control content performed by ECU of an internal combustion engine. It is a figure for demonstrating the effect of this invention. It is a figure for demonstrating the effect of this invention. It is a figure for demonstrating the effect of this invention.

(First embodiment)
A first embodiment in which the present invention is applied to an automobile internal combustion engine will be described with reference to the drawings. FIGS. 1A and 1B are a schematic view and a main part sectional view showing a main part configuration of the fuel heating device, and FIG. 1A corresponds to a sectional view taken along the line II in FIG. 1B. To do. FIG. 2 is a schematic view showing a fuel injection device configuration of an internal combustion engine provided with a fuel heating device. In FIG. 2, an internal combustion engine (not shown) is a multi-cylinder engine (four cylinders in this example) that uses alcohol-containing fuel as fuel, and supplies fuel from the injector I corresponding to each cylinder into the combustion chamber. . A fuel heating section 2 including a pair of fuel heating pipes 2a and 2b is installed immediately above the four injectors I arranged in parallel, and a main delivery pipe 1 communicating with the fuel tank T is disposed above the fuel heating section 2. Has been.

  The alcohol-containing fuel stored in the fuel tank T is a fuel mainly composed of alcohol such as methanol or ethanol, and a mixed fuel obtained by mixing gasoline and alcohol is used in addition to 100% alcohol fuel. Although the alcohol content in the mixed fuel is arbitrary, it is particularly effective when the present invention is applied to a fuel that preferably contains alcohol at a high concentration of 85% or more. Alcohol-containing fuel is expected to increase in demand as an alternative fuel for petroleum, and handling that takes into account the difference in physical properties such as a low boiling point component less than conventional gasoline fuel and a large latent heat of vaporization is required.

  The main delivery pipe 1 has a rectangular tube shape with both ends closed, and a fuel pipe 11 extending from the fuel tank T is connected to one end side surface (the right end surface in the figure). The main delivery pipe 1 is provided with connecting pipes 1a and 1b as tubular portions that protrude downward from the left and right ends of the bottom surface thereof, and the lower fuel heating pipe 2a, 2b, respectively.

  The fuel heating pipes 2a and 2b of the fuel heating unit 2 are provided corresponding to two adjacent ones of the four injectors I arranged in parallel. The fuel heating pipes 2a, 2b have a flat sealed tube shape with a rectangular cross section, and the connection pipes 1a, 1b are connected to an opening provided at the center of a flat flat top surface (flat surface), respectively. It has become. The bottom surfaces of the fuel heating pipes 2a and 2b are flat surfaces having the same shape as the top surface, and mounting pipes 21a, 21b, 22a and 22b as tubular portions project from the left and right ends, respectively. These four attachment pipes 21a, 21b, 22a and 22b correspond to the four injectors I provided for each cylinder and are attached to the head of the injector I having an opening for fuel introduction.

  The fuel heating pipes 2a and 2b are made of, for example, a material having a high magnetic permeability with a thickness of about 0.2 to 0.3 mm, for example, a steel material. It is desirable that the attachment pipes 21a, 21b, 22a, 22b and the connection pipes 1a, 1b are also made of the same material having high magnetic permeability, for example, steel. Thereby, it can be set as the structure which can heat | fever-generate the pipe itself by the induction heating mentioned later.

  As shown in FIGS. 1A and 1B, the fuel heating section 2 includes spiral induction heating coils 5 on the top and bottom surfaces of the flat fuel heating pipes 2a and 2b that are opposed to each other. ing. An insulating layer 4 is formed on the entire surface of the top and bottom surfaces of the fuel heating pipes 2a and 2b with which the induction heating coil 5 abuts. The insulating layer 4 is formed by covering the surfaces of the fuel heating pipes 2a and 2b with an insulating resin film having a thickness of about 0.1 mm, for example, a polyimide film. The insulating layer 4 is also formed on the surfaces of the connection pipes 1a, 1b and the attachment pipes 21a, 21b, 22a, 22b, at least in the vicinity of the connection portion with the fuel heating pipes 2a, 2b.

  The insulating layer 4 has a role of keeping the clearance between the fuel heating pipes 2 a and 2 b and the induction heating coil 5 constant, allowing an induction current to flow efficiently, and preventing the heat of the pipe from being conducted to the induction heating coil 5. 1A and 1B, only the fuel heating pipe 2a of the fuel heating unit 2 is shown for convenience, but the configuration on the fuel heating pipe 2b side is the same as shown in FIG. ing.

  The induction heating coil 5 is centered on the pipe so as to surround the connecting pipes 1a, 1b and the connecting pipes 21a, 21b, 22a, 22b at least at the center of the top surface and both ends of the bottom surface of the fuel heating pipes 2a, 2b. It is formed by winding the coil concentrically. Further, as shown in the figure, preferably, the same spiral shape is formed so as to surround the opposing portions of the connecting pipes 1a, 1b and the mounting pipes 21a, 21b, 22a, 22b at the top end and the bottom center. Is done. If it does in this way, the connection part periphery with the connection pipes 1a and 1b and the attachment pipes 21a, 21b, 22a, and 22b through which the alcohol-containing fuel flows can be efficiently heated. In addition, since the connecting pipes 1a and 1b are connected to the center of the fuel heating pipes 2a and 2b, and the attachment pipes 21a, 21b, 22a and 22b are disposed on both sides thereof, the four injectors I are heated evenly. Is supplied.

  At this time, as shown in FIGS. 1A and 2, the induction heating coil 5 is formed as a continuous coil in which a plurality of spiral coils are connected, and both ends thereof are connected to the high-frequency power source 6. For example, on the top surface of the fuel heating pipe 2a, from the left end portion to the right end portion, alternately from the inside to the outside, or from the outside to the inside so that the periphery of the connection portion (or the opposite portion) is in the same winding direction. The spiral coils 5a, 5b, and 5c wound around the inner periphery of the coil 5a are disposed at the high frequency power source 6, and the outer periphery of the coil 5c is disposed at the top surface of the fuel heating pipe 2b in FIG. It connects with the inner peripheral end of the coil 5a. On the bottom surface of the fuel heating pipe 2a, spiral coils 5a ', 5b' and 5c 'are wound at positions symmetrical to the spiral coils 5a, 5b and 5c, and the outer peripheral end of the coil 5c' is shown in FIG. The inner peripheral end of the coil 5a ′ is connected to the high frequency power source 6 at the inner peripheral end of the spiral coil 5a ′ on the bottom surface of the pipe 2b. On the bottom side, when the spiral coil 5c ′ at the right end is alternately wound from the outside to the inside and then from the inside to the outside, the shape of the top side coil is reversed (the same shape when viewed from the injector I side). ), And the current in the same direction flows at the same time as the opposing coils.

  In this way, after the spiral coils 5a, 5b, 5c having the same winding direction are formed on the top surfaces of the fuel heating pipes 2a, 2b, a series of spiral coils are formed on both sides in the same manner. The coils can be arranged densely. The number of turns of the coil is set to be a plurality of, for example, four or five, spirals depending on the required amount of heat generation. Preferably, as shown in FIG. 1A, when the spiral coils 5a, 5b, and 5c have substantially the same shape and are arranged so as to substantially cover the entire top surfaces of the fuel heating pipes 2a and 2b, the fuel heating pipe 2a and 2b can be heated satisfactorily. Further, since the currents flowing through the spiral coils 5a, 5b and 5c on the top surface side and the spiral coils 5a ′, 5b ′ and 5c ′ on the bottom surface side are in the same direction, the generated magnetic field is strengthened and the heating efficiency is improved. .

  Outside the induction heating coil 5, the entire fuel heating pipes 2a and 2b, the induction heating coil 5 on the surface, the fuel heating pipes 2a and 2b, the connecting pipes 1a and 1b, and the mounting pipes 21a, 21b, 22a and 22b are provided. And an insulating layer 8 is provided. The insulator layer 8 can be easily formed by molding or the like in which a resin material is filled in a mold and solidified, and the embedded induction heating coil 5 is fixed on the fuel heating pipes 2a and 2b, and at the same time, Insulate and protect. Thereby, for example, water droplets are prevented from adhering to the induction heating coil 5, and heat of the fuel heating pipes 2a and 2b is prevented from being released to the outside air.

  A temperature sensor 3 is attached to the top surface of the fuel heating pipe 2a to detect the temperature by contacting the surface of the pipe body. The temperature sensor 3 is disposed below the insulating layer 4 and indirectly detects the temperature of the alcohol-containing fuel flowing through the pipe surface temperature. Signals from the temperature sensor 3, and further from a door switch, a key switch, and an engine water temperature sensor (not shown) are input to an ECU 7 serving as control means. The ECU 7 controls power supply from the high frequency power source 6 to the induction heating coil 5 based on these signals.

  The fuel heating unit 2 of the present embodiment supplies a high-frequency current to the induction heating coil 5 to generate a magnetic field, and heats the fuel heating pipes 2 a and 2 b disposed close to each other via the insulating layer 4. Since the fuel heating pipes 2a and 2b have a flat tube shape, a sufficient space for arranging the induction heating coil 5 in a spiral shape on the top and bottom surfaces of the flat plate shape is obtained. In addition, the induction heating coil 5 is disposed, and the distance between the top and bottom surfaces of the fuel heating pipes 2a and 2b serving as heat generating portions is reduced (for example, about several mm or less), and the alcohol-containing fuel flowing inside is heated evenly. Can do.

  Here, the volume of the fuel heating pipes 2a and 2b is set to a predetermined volume that can accommodate the amount of fuel required at the time of starting. The predetermined volume varies depending on the size of the engine, the alcohol content of the fuel, the set heating temperature, and other specifications, but usually the total volume of the fuel heating pipes 2a and 2b is about 10 ml or more, for example, 15 ml. This amount corresponds to the amount of fuel necessary for the general four-cylinder engine shown in the figure to start and reach a rotational speed of 1000 rpm. Therefore, the fuel heating pipes 2a and 2b have an induction heating coil 5 whose top surface and bottom surface can generate a magnetic field capable of raising the predetermined volume of fuel to a predetermined heating temperature (for example, 50 ° C.), the connecting pipe 1a, 1b, having an area that can be sufficiently arranged in a spiral shape around the connecting portion of the attachment pipes 21a, 21b, 22a, 22b, and the distance between the top surface and the bottom surface can be made sufficiently small to uniformly heat the internal fuel It is good to set suitably so that it may become a flat shape.

(Second Embodiment)
FIG. 3 shows a second embodiment of the present invention in which the internal structure of the fuel heating pipe is changed. FIG. 3B is a cross-sectional view of the main part of the fuel heating device, and FIG. A cross-sectional view is shown. The basic structure is the same as in FIG. 1 and only the heating device structure on the fuel heating pipe 2a side is shown, but the fuel heating pipe 2b side is also the same.

  In this embodiment, as shown to Fig.3 (a), many labyrinth plates 23 are provided in the fuel heating pipes 2a and 2b. These labyrinth plates 23 are elongated plate-like members arranged in parallel so as to divide the inside of the fuel heating pipes 2a and 2b in the long side direction (left and right direction in the figure), and one end side is opposed to the fuel heating pipes 2a and 2b. Are alternately fixed to one of the inner walls, and the other end extends to a position in the vicinity of the opposite inner wall. The upper and lower sides of the labyrinth plate 23 are fixed to the upper and lower inner surfaces of the fuel heating pipes 2a and 2b.

  Thereby, in the fuel heating pipes 2a and 2b, a large number of labyrinth plates 23 provided in a comb-teeth shape at substantially equal intervals on the opposing inner side walls are alternately arranged, and a series of meandering flow paths are provided. Form. At this time, the connecting pipe 1a connected to the delivery pipe 1 serves as a fuel inlet, and the alcohol-containing fuel that has flowed in is divided into two flows along the labyrinth plate 23 toward both side walls. One of the flows passes through a flow path formed between the labyrinth plates 23 and becomes a flow F1 toward the attachment pipe 21a, and the other becomes a flow F2 toward the attachment pipe 21b and is supplied to the injector I.

  As described above, in this embodiment, by installing the labyrinth plate 23, the flow path length in the fuel heating unit 2 is increased, and the chance of contact with the labyrinth plate 23 that functions as a heat transfer plate is increased. The alcohol-containing fuel to be heated can be uniformly and efficiently heated.

  In the first embodiment, the spiral coils 5a, 5b, and 5c of the induction heating coil 5 and the spiral coils 5a ′, 5b ′, 5c ′ is arranged so as to be in a symmetrical position and shape, but it is not always necessary to be in a substantially symmetrical position. In the present embodiment, in the spiral coils 5d, 5e, 5f on the top surface of the fuel heating pipes 2a, 2b and the spiral coils 5d ′, 5e ′, 5f ′ on the bottom surface, the connecting pipes 1a, 1b or the attachment pipes 21a, 21b are used. , 22a, 22b (spiral coils 5d, 5f, 5e ′ in the figure) are arranged so that the center circle of the induction heating coil 5 is smaller and the outer diameter is smaller. Also in this case, the center of the induction heating coil 5 is set to be on the central axis of the connection pipes 1a, 1b or the attachment pipes 21a, 21b, 22a, 22b. Further, winding is performed so that the currents flowing through the spiral coils 5d, 5e, and 5f on the top surface side and the spiral coils 5d, 5f, and 5e 'on the bottom surface side are in the same direction. In this way, the installation space for the induction heating coil 5 is reduced, which is effective, for example, when the shape of the fuel heating pipes 2a, 2b is restricted or when it is desired to increase the number of turns of the induction heating coil 5.

(Third embodiment)
FIG. 4 is a third embodiment of the present invention in which an installation location of the induction heating coil 5 is added. The basic structure is the same as in FIG. 1 and only the heating device structure on the fuel heating pipe 2a side is shown, but the fuel heating pipe 2b side is also the same.

  In the present embodiment, as shown in the drawing, in addition to the flat wound induction heating coil 5 installed on the top and bottom surfaces of the fuel heating pipes 2a and 2b, an injector connected to the bottom surfaces of the fuel heating pipes 2a and 2b. An induction heating coil 51 is installed on the outer periphery of the pipes 21a, 21b, 22a, 22b attached to I. The induction heating coil 51 is formed as a series of coils together with the induction heating coil 5 composed of a plurality of spiral coils. The induction heating coil 5 on the bottom surface of the fuel heating pipes 2a and 2b is followed by the attachment pipe 21a. , 21b, 22a, 22b are formed in a spiral shape so as to surround the outer periphery. The outer peripheral surfaces of the attachment pipes 21a, 21b, 22a, 22b are protected by the insulating layer 4. Specifically, the spiral coils 5a, 5b, and 5c on the top surfaces of the fuel heating pipes 2a and 2b and the spiral coils 5a ′, 5b ′, and 5c ′ on the bottom surface are arranged in the same manner as in the first embodiment, and the winding direction. When winding the spiral coils 5a ′ and 5c ′ at both ends to be the induction heating coil 5 on the bottom surfaces of the fuel heating pipes 2a and 2b, the spiral induction heating coil 51 is wound in the same winding direction. Wrap to be a stretch.

  Thereby, when the fuel heating unit 2 is operated, the magnetic field concentrates on the attachment pipes 21a, 21b, 22a, 22b to the injector I, and the temperature becomes high. Therefore, the fuel flowing into the injector I can be heated more effectively, and the temperature can be raised to a predetermined temperature in a short time.

(Fourth embodiment)
FIG. 5 is a fourth embodiment of the present invention in which the winding method of the induction heating coil 5 is changed, and FIGS. 5A and 5B are Ia-Ia lines of FIG. It is sectional drawing, Ib-Ib sectional view taken on the line. The basic structure is the same as that of the first embodiment shown in FIG. 1, and only the heating device structure on the fuel heating pipe 2a side is shown, but the fuel heating pipe 2b side is also the same.

  In the present embodiment, as shown in the figure, a flat-wound induction heating coil 5 is installed on the top and bottom surfaces of the fuel heating pipes 2a and 2b. For example, on the top surface of the fuel heating pipe 2a, a connecting portion is provided. The spiral coil 5g at the left end is from the inside to the outside, and the spiral coils 5h and 5i at the center and the right end are from the outside so that the winding direction around the coil (or the opposite part) is opposite in the adjacent coil. Winding inward (FIG. 5A). The bottom surface of the fuel heating pipe 2a also has spiral coils 5g, 5h, 5i on the top surface side so that the winding direction around the connecting portion (or the opposite portion) is reversed between adjacent coils, and at the opposite position. The spiral coils 5i ′, 5h ′, and 5g ′ are wound from the outer side to the inner side from the right end to the left end so that the direction of current flow is the same (FIG. 5B).

  If it does in this way, spiral coil 5g, 5h, 5i and spiral coil 5g ', 5h', 5i so that the pipe | tube with which a fuel distribute | circulates may be surrounded in the opposing position of the top face and bottom face of fuel heating pipe 2a, 2b. 'Is arranged, currents in the same direction flow at the same point, and the fuel heating pipes 2a and 2b are effectively heated by the induced current. Further, when the winding direction of the adjacent spiral coils is reversed, the current flows in the same direction in the adjacent outermost coil and acts in the direction in which the generated magnetic field is strengthened, so that the heating efficiency is further improved.

(Fifth embodiment)
FIG. 6 shows a fifth embodiment of the present invention in which the winding method of the induction heating coil 5 is changed, and FIGS. 6A and 6B are Ia-Ia lines of FIG. It is sectional drawing, Ib-Ib sectional view taken on the line. The basic structure is the same as that of the first embodiment shown in FIG. 1, and only the heating device structure on the fuel heating pipe 2a side is shown, but the fuel heating pipe 2b side is also the same.

  In the present embodiment, the spiral induction heating coil 51 shown in the third embodiment of FIG. 4 is additionally installed in the configuration of the fourth embodiment of FIG. That is, as shown in the drawing, the spiral coils 5g, 5h, and 5i on the top surface of the fuel heating pipe 2a and the spiral coils 5g ′, 5h ′, and 5i ′ on the bottom surface are arranged and wound in the same manner as in the fourth embodiment. When the spiral coils 5g ′ and 5i ′ at both ends to be the induction heating coil 5 are wound on the bottom surface of the fuel heating pipe 2a, the spiral induction heating coil 51 is continuously stretched in the same winding direction. Wrap to become. The outer peripheral surfaces of the pipes 21 a and 21 b attached to the injector I where the induction heating coil 51 is formed are protected by the insulating layer 4.

  Thereby, when the fuel heating unit 2 is operated, the magnetic field concentrates on the pipes 21a, 21b, 22a and 22b attached to the injector I, and the fuel flowing into the injector I can be heated more effectively. Is further improved.

(Operation of the fuel heating device of the present invention)
Next, the operation of the fuel heating apparatus of the present invention will be described with reference to the flowchart of FIG. In the apparatus configuration of the first to third embodiments shown in FIGS. 1 to 4, detection signals from the temperature sensor 3 and the engine water temperature sensor are input to the ECU 7 serving as the control means, and from the door switch and key switch. The signal is input. 47, when a signal indicating that the door switch is activated and the door on the driver's seat is opened is input in step 1 of FIG. 47, the surface temperature of the fuel heating pipes 2a and 2b, that is, the fuel temperature is set to a predetermined temperature T1. It is determined whether or not. If the fuel temperature is equal to or lower than the predetermined temperature T1, it is determined that heating at start-up is necessary, and the process proceeds to step 2. If the fuel temperature is higher than the predetermined temperature T1, the process ends.

  If the determination in step 2 is affirmative, the process proceeds to step 3 to determine whether or not the engine coolant temperature is equal to or lower than a predetermined temperature T2 based on a signal from the engine coolant temperature sensor. For example, immediately after the engine is stopped, the engine is warmed and heating is not required even if the fuel is at a low temperature. Therefore, if the cooling water temperature is higher than the predetermined temperature T2, the process is terminated.

  If step 3 is affirmed, the process proceeds to step 4 to operate the fuel heating unit 2 and start high-frequency induction heating. Here, first, a high frequency current (for example, 35V, 30A at about 17 kHz) is supplied from the high frequency power source 5 to the induction heating coil 5 to heat the fuel in the fuel heating pipes 2a and 2b. This mechanism will be described with reference to FIG.

  In FIG. 2, the alcohol-containing fuel in the fuel tank T is pumped by a fuel pump (not shown) and flows into the main delivery pipe 1 through the fuel pipe 11. At both ends of the main delivery pipe 1, connecting pipes 1a and 1b with fuel heating pipes 2a and 2b are provided, and the fuel flows into the fuel heating pipes 2a and 2b from here.

  On the other hand, the induction heating coil 5 is wound around the outer periphery of the pipe connecting portion and the position opposite thereto on the top and bottom surfaces of the fuel heating pipes 2a and 2b, and when a high frequency current flows through the coil 5, the fuel heating pipe 2a 2b generates a magnetic field. By this magnetic field, an induction current flows through the fuel heating pipes 2a and 2b and the injector mounting pipes 21a, 21b, 22a and 22b, and the entire pipe generates heat, and the fuel flowing through the inside is heated by the heat. In particular, the temperature of the connecting pipes 1a, 1b and the attachment pipes 21a, 21b, 22a, 22b to the injector I where the magnetic field is concentrated is increased, so that the fuel flowing into the injector I is effectively heated and the temperature is increased. There is.

  The ECU 7 heats the fuel based on the input signal from the temperature sensor 3 until, for example, the detected temperature reaches a predetermined temperature (about 50 ° C.). In the case where it takes time from the opening of the door to the start, it is preferable that the current is intermittently supplied to maintain the predetermined temperature (about 50 ° C.) until the key switch is turned on. In step 5, it is determined whether or not the key switch is turned on. If the determination is negative, this step is repeated until an on signal is input. When an ON signal is input from the key switch in step 5, the energization from the high frequency power source 5 is stopped and the heating process is terminated.

  Alternatively, as shown in the flowchart of FIG. 8, it is possible to perform control to continue the operation of the fuel heating device even after the key switch is turned on. For example, it is effective when the time from the opening and closing of the door to the start is short, and the temperature is not sufficiently increased when the key switch is turned on. FIG. 8 is obtained by adding Step 6 to the flowchart of FIG. 7 and Steps 1 to 5 are the same. In this case, since it is necessary to flow a large current through the starter when cranking is started, the current supply to the fuel heating unit 2 is temporarily stopped. When the engine is started, the current is intermittently supplied so that the predetermined temperature (about 50 ° C.) is maintained. In step 6, it is determined whether or not the engine speed exceeds the predetermined speed N. When step 6 is positively determined and the engine speed is increased to a predetermined engine speed N, the operation is stopped. If step 6 is negatively determined, this step is repeated until a predetermined rotational speed N is exceeded. Further, when the fuel temperature starts to decrease due to the fuel being injected and the fuel entering the heating pipe, the heating can be started again.

  FIGS. 9 and 10 are diagrams showing the effect of this heating extension, and the control for continuing the heating (heating extension) after the control (preheating) for stopping the current supply to the fuel heating unit 2 when the starter is turned on. Is carried out, the surface temperature of the fuel heating pipes 2a and 2b and the fuel temperature continue to rise, and the temperature drop after the start of injection becomes smaller. As a result, the temperature rise effect shown in FIG. 11 (d) is obtained. As shown in FIGS. 11 (a) to 11 (c), the minimum energy that can be started increases with respect to the preheat, but the minimum power that can be started. Can be reduced and the starting time can be shortened.

T Fuel tank 1 Main delivery pipe (delivery pipe)
11 Fuel pipe 1a, 1b Connecting pipe (tubular part)
2 Fuel heating part 2a, 2b Fuel heating pipe 22a, 22b Installation pipe (tubular part)
21a, 21b Mounting pipe (tubular part)
DESCRIPTION OF SYMBOLS 3 Temperature sensor 4 Insulating layer 5 Induction heating coil 5a-5i Spiral coil 5a'-5i 'Spiral coil 51 Induction heating coil 6 High frequency power supply 7 ECU (control means)
8 Insulator layer

Claims (9)

  A fuel heating device attached to a fuel injection device of an internal combustion engine, wherein a delivery pipe serving as a supply path for alcohol-containing fuel stored in a fuel tank and an injector for fuel injection are arranged in proximity to the injector A plurality of tubular portions that serve as connecting portions between the injector and the delivery pipe are provided on the flat surface of the fuel heating pipe and project through at least a flat surface of the fuel heating pipe. A fuel heating apparatus for an internal combustion engine, wherein an induction heating coil is disposed in a spiral shape around the tubular portion on the flat surface around the tubular portion, and a high frequency power source is connected to the induction heating coil. .   The fuel heating pipe is induction-heated in a spiral shape substantially symmetrical to the induction heating coil disposed around the tubular portion on a flat surface facing the tubular portion to which the injector or the delivery pipe is connected. 2. A fuel heating apparatus for an internal combustion engine according to claim 1, further comprising a coil.   The induction heating coil disposed on the flat surface around the tubular portion and the induction heating coil disposed on the flat surface facing the tubular portion have the same direction of flowing current. 3. The fuel heating apparatus for an internal combustion engine according to claim 2, wherein a winding direction of the coil is set in the internal combustion engine.   The plurality of induction heating coils disposed adjacent to the same flat surface of the fuel heating pipe have the same direction of current flowing in the adjacent outermost coils. The fuel heating apparatus for an internal combustion engine according to claim 2 or 3, wherein a winding direction of the coil is set.   The fuel heating apparatus for an internal combustion engine according to any one of claims 1 to 4, wherein the fuel heating pipe is made of a magnetic material and an insulating layer is formed on an outer surface thereof.   Temperature detection means for directly or indirectly detecting the fuel temperature in the fuel heating pipe, and control means for controlling the high frequency current supplied from the high frequency power source to the induction heating coil based on the detection result of the temperature detection means The fuel heating apparatus for an internal combustion engine according to any one of claims 1 to 5, wherein   The tubular portion is made of a magnetic material, and an insulating layer is formed on the outer peripheral surface of the tubular portion, and an induction heating coil surrounding the surface of the tubular portion is provided. The fuel heating apparatus for an internal combustion engine according to any one of claims 6 to 6.   8. The induction heating coil disposed on the flat surface of the fuel heating pipe and the outer peripheral surface of the tubular portion is constituted by a continuous continuous coil. A fuel heating apparatus for an internal combustion engine according to claim 1.   A plurality of the tubular portions connected to the plurality of injectors are provided on one of the opposed flat surfaces of the fuel heating pipe, and the tubular portions connected to the delivery pipe are connected to the injector on the other flat surface. The fuel heating apparatus for an internal combustion engine according to any one of claims 1 to 8, characterized in that the distance from the plurality of tubular portions is substantially equal.