JP2011080378A - Fuel heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel heating device capable of raising the temperature of fuel in an outlet. <P>SOLUTION: In this fuel heating device, a heater 20 is inserted and fixed to a case 10 including: a fuel housing part 11 capable of housing fuel inside thereof; a lead-in opening 12 for leading fuel into the fuel housing part 11; and a discharge opening 13 for discharging fuel from the fuel housing part 11. The discharge opening 13 is arranged in a region on an upper side of heating part, a region higher than a virtual plane vertical to the direction of gravity passing through the center 22 of the maximum heating part of the heater 20, and the lead-in opening 12 is arranged on a lower side of the discharge opening 13 in the direction of gravity. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fuel heating apparatus for heating fuel supplied to an internal combustion engine.

  In internal combustion engines used for automobiles and the like, alcohol or a mixed fuel of alcohol and gasoline has been used in addition to gasoline and light oil that have been used conventionally. In particular, when bioethanol is used as a fuel, there is a possibility that the emission of carbon dioxide can be reduced to protect the global environment, and the use of bioethanol as a fuel has attracted attention.

  As described above, when alcohol is used as the fuel for the internal combustion engine, the startability particularly during a cold start is deteriorated. For this reason, a subtank containing gasoline is prepared, and gasoline is used as fuel at the time of starting. Further, as a technique for improving the startability at the cold start, a technique for providing a fuel heating device for heating the fuel supplied to the internal combustion engine is known. In this technique, a rod-shaped heater is provided in a cylindrical tube (fuel storage portion) arranged vertically or horizontally, and the fuel in the cylindrical tube is heated by this heater. In such a fuel heating device, the fuel inlet into the pipe and the fuel outlet from the pipe are positioned above the outlet in the gravity direction in consideration of the flow of fuel due to gravity. (For example, refer to Patent Document 1 and Patent Document 2).

JP-A-5-26130 JP-A-5-18328

  As described above, the conventional fuel heating apparatus has a configuration in which a rod-shaped heater is provided in a cylindrical pipe arranged vertically or horizontally, and the fuel inlet into the pipe and the discharge of the fuel from the pipe. In consideration of the flow of fuel due to gravity, the outlet is arranged such that the inlet is positioned above the outlet in the direction of gravity.

  However, as a result of detailed investigations by the present inventors, in the conventional fuel heating apparatus having the above-described configuration, the fuel heated by the heater and heated to a high temperature rises in the pipe, and the relatively low-temperature fuel flows into the pipe. Convection occurs to descend to the bottom. For this reason, there has been a problem that fuel at a relatively low temperature is discharged from the discharge port provided in the lower portion, and the fuel outlet temperature in the fuel heating device is lowered. In addition, such a problem tends to be particularly noticeable due to the influence of bubbles generated by boiling when the fuel is heated so that the fuel is boiled in the fuel heating device.

  The present invention has been made to solve the above problems. An object of this invention is to provide the fuel heating apparatus which can make the exit temperature of the fuel in a fuel heating apparatus high.

  The fuel heating device of the present invention includes a fuel storage portion that is capable of storing fuel therein, an introduction port for introducing fuel into the fuel storage portion, and an exhaust for discharging the fuel from the fuel storage portion. A fuel heating device in which a heater is inserted and fixed to a case having an outlet, and the fuel in the fuel storage portion is heated by the heater, passing through the center of the highest heat generating portion of the heater, and in the direction of gravity The discharge port is disposed in a heating upper region, which is a region above a virtual plane perpendicular to the vertical plane, and the introduction port is disposed below the discharge port in the gravitational direction.

  In the fuel heating device of the present invention having the above-described configuration, the upper side of the heating, which is the region above the virtual plane perpendicular to the direction of gravity, the discharge port of the fuel storage portion into which the heater is inserted and fixed passes through the center of the highest heat generating portion of the heater. A discharge port is disposed in the region, and an introduction port is disposed below the discharge port in the direction of gravity. By adopting such a configuration, the fuel heated by the heat generating portion of the heater forms an ascending flow and is led out from the heating upper region in the fuel storage portion to the fuel injection device through the discharge port. be able to. Accordingly, the fuel outlet temperature can be made higher than that of a conventional fuel heating device in which a discharge port is provided in the lower portion of the fuel storage portion in consideration of the flow of fuel due to gravity.

  In the fuel heating device having the above configuration, when the heater is disposed to be inclined with respect to the direction of gravity, the discharge port is preferably configured to be disposed in a region above the axis of the heater in the case. Thus, by arranging the discharge port in the region above the heater axis, the fuel heated by the heater and heated to a high temperature can be quickly discharged from the discharge port, and the fuel outlet temperature is increased. can do.

  Moreover, in the fuel heating apparatus having the above configuration, it is preferable that the introduction port is arranged in a heating lower region that is a region below the virtual plane. Thus, by arranging the introduction port in the heating lower region, the low-temperature fuel can flow from the lower side to the heating portion of the heater without hindering the rising flow of the fuel heated by the heating portion of the heater described above. A flow of the supplied fuel can be formed. This makes it possible to efficiently heat the fuel and increase the fuel outlet temperature.

  In the fuel heating apparatus having the above-described configuration, the heating temperature of the highest heating portion is higher than the boiling point of the fuel when the fuel is heated by the heater. As described above, when the fuel heated by the heater reaches the boiling point, bubbles are generated in the vicinity of the highest heat generating portion. The convection driving force can be obtained by the bubbles, and the fuel can be heated more effectively by making the convection more active.

  In the fuel heating device having the above configuration, the case can be configured to have an inner diameter larger than an inner diameter of a pipe connecting the fuel supply common pipe and the fuel injection apparatus. In other words, this configuration can also be said to make the fuel storage part a separate “room” different from the pipe connecting the fuel supply common pipe and the fuel injection device. In other words, the fuel heated in the fuel storage section may move to the inside of the fuel supply common pipe depending on the piping, but this configuration allows the fuel inside the room (fuel storage section) to move. This facilitates convection, and the fuel staying immediately before the fuel injection device is efficiently heated.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel heating apparatus which can make the exit temperature of the fuel in a fuel heating apparatus high can be provided.

The figure which shows the longitudinal cross-sectional schematic structure of the fuel heating apparatus which concerns on one Embodiment of this invention. The figure which shows typically FIG. 1 for demonstrating the positional relationship of an inlet and an outlet. The graph which shows the result of having measured the relationship between the energization time in the fuel heating apparatus of FIG. 1 and a comparative example, and the raise of exit temperature. The figure which shows the longitudinal cross-section schematic structure of the modification of embodiment. The figure which shows the longitudinal cross-section schematic structure of the modification of embodiment. The figure which shows the structure seen from the axial direction about embodiment and the modification. The figure which shows the longitudinal cross-section schematic structure of the fuel heating apparatus which concerns on a comparative example.

  Embodiments of the present invention will be described below with reference to the drawings. In FIGS. 1, 2, 4, and 5 and FIG. 7 showing the comparative example, the vertical direction of the paper surface is the direction of gravity (indicated by the alternate long and short dash line V in the figure). FIG. 1 shows a schematic longitudinal sectional configuration of a fuel heating apparatus 100 according to an embodiment of the present invention. The fuel heating apparatus 100 shown in the figure includes a case 10 whose internal shape is formed in a substantially cylindrical shape. The inside of the case 10 is configured as a fuel storage portion 11 that can store fuel. An inlet 12 for introducing fuel into the fuel storage unit 11 is formed at the lower end of the case 10, and fuel is discharged from the fuel storage unit 11 near the upper end of the case 10. A discharge port 13 is formed for this purpose. Further, an insertion port 14 for inserting the heater 20 into the fuel accommodating portion 11 is formed at the upper end portion of the case 10.

  The case 10 is a main portion of the fuel containing portion 11 and has a large-diameter portion 11b having a large inner diameter, a discharge port 13 having a smaller inner diameter than the large-diameter portion 11b, and similarly having an inner diameter larger than that of the large-diameter portion 11b. It has a small inlet 12. The insertion port 14 has a circular shape, and the center thereof is formed on the axis CA of the fuel storage portion 11. Since the heater 20 is inserted into and fixed to the insertion port 14, the gap between the inner peripheral surface of the case 10 and the outer peripheral surface of the heater 20 is substantially constant in the radial direction. The heater 20 is fixed to the case 10 by a lid 30 of the heater 20 described later.

  In the present embodiment, the heater 20 is configured as a sheath heater in which a heating resistor is disposed at a distal end portion in a metal sheath whose one end (the distal end side in FIG. 1) is closed. The rear end side is composed of a part (lid 30) for sealing the sheath or holding the sheath. In addition, an external power source (not shown) is connected to the rear end portion so that power can be supplied to the heating resistor. The heater 20 is configured such that a heating resistor is disposed at the distal end portion, and the distal end portion of the sheath becomes the highest heating portion 21. As described above, when the heater 20 generates heat, the tip side reaches the maximum temperature. In addition, the surface temperature of the heaters 20 other than the highest heat generating portion 21 is also heated to the temperature of the highest heat generating portion 21 or less.

  The positional relationship between the introduction port 12 and the discharge port 13 with respect to the fuel storage unit 11 will be described with reference to FIG. 2 schematically showing FIG. An area above the imaginary plane (indicated by the alternate long and short dash line H in the figure) perpendicular to the direction of gravity (indicated by the alternate long and short dash line H in the figure) passing through the center 22 of the heater 20 of the heater 20 and the vertical direction. Is the heating upper region, and the lower region is the heating lower region, the discharge port 13 is disposed in the heating upper region, and the introduction port 12 is disposed below the discharge port 13 in the gravitational direction. In the present embodiment, the inlet 12 is disposed in the heating lower region.

  The upper opening 14 of the case 10 is closed by the lid body 30, and the heater 20 is supported by the lid body 30. Further, the heater 20 is disposed such that its own axis HA coincides with the gravity direction V and also coincides with the axis CA of the fuel storage unit 11. Note that an alternate long and short dash line HA shown in FIG. 1 indicates an axis of the heater 20.

  A fuel supply individual pipe 111 branched from the fuel supply common pipe 110 is connected to the introduction port 12 of the fuel heating apparatus 100 having the above configuration. A fuel injection device 120 is connected to the discharge port 13 of the fuel heating device 100.

  In the fuel heating device 100 configured as described above, when the internal combustion engine is started, the internal combustion engine piston passes through the fuel supply common pipe 110 and the fuel supply individual pipe 111 before starting (cranking) by the cell motor or the like. A fuel such as alcohol supplied to the fuel storage portion 11 of the case 10 is heated in advance (preliminary heating) by energizing the heater 20. The preheating time is about several seconds to several tens of seconds. Thereafter, the piston of the internal combustion engine is cranked, and the supply of fuel from the fuel storage unit 11 to the fuel injection device 120 is started. During the cranking, the fuel flows in the fuel accommodating portion 11 due to the discharge of the fuel from the fuel accommodating portion 11 and the inflow of the fuel into the fuel accommodating portion 11. Is continued and heating of the fuel is continued.

  When the heater 20 is energized during the preheating of the fuel by the fuel heating device 100 described above, the fuel heated in the vicinity of the heat generating portion 21 of the heater 20 passes between the inner wall of the case 10 and the heater 20 and passes through the case 10. Flows upward. On the other hand, the low-temperature fuel is pushed by the above-described fuel flow, passes between the inner wall of the case 10 and the heater 20, and forms a flow from below to the heat generating portion 21 of the heater 20. Due to such a flow, convection is generated in the case 10. Such fuel convection becomes more effective when the fuel boils and bubbles are generated in the fuel.

  In the graph of FIG. 3, the vertical axis indicates the temperature rise (change) and the horizontal axis indicates the time, and the outlet at the discharge port 13 portion of the fuel heating device 100 when water is heated by the fuel heating device 100 instead of the fuel. The result of measuring the temperature change is shown. In the figure, a curve B plotted with square marks indicates the case of the fuel heating apparatus 100 of the present embodiment, and a curve C plotted with rhombus marks indicates the case of the comparative example. In the measurement, the heater 20 is heated at about 100 W for about 8.5 seconds with no outflow of water, and then the portion of the discharge port 13 when water heated at 40 cc / min is discharged from the discharge port 13 is measured. This was done by measuring the temperature rise of the effluent. Each temperature measuring point is a point B shown in FIG. 2 and a point C shown in FIG.

  As shown in FIG. 7, the measurement of the above comparative example uses a fuel heating device 100 ′ having a configuration in which an inlet 12 is provided at the upper part of the case 10 ′ and an outlet 13 is provided at the lower part of the case 10 ′. I went. That is, in the fuel heating apparatus 100 ′, the discharge port 13 is disposed in the heating lower region below the virtual plane perpendicular to the direction of gravity through the heat generation center point 22 of the heater 20 indicated by a one-dot chain line H in the drawing. The inlet 12 is disposed above the outlet 13 in the direction of gravity. In FIG. 7, the same reference numerals are given to the portions corresponding to the fuel heating device 100 of FIG.

  As shown in the graph of FIG. 3, in the fuel heating device 100 of the present embodiment, the outlet temperature of the discharge port 13 can be made higher than in the case of the fuel heating device 100 ′ of the comparative example. In addition, when water was poured from the top of the fuel heating device 100 and the fuel heating device 100 ′ by a drop from a height of 0.27 m, the flow of water in the fuel heating device 100 and the fuel heating device 100 ′ was compared. The flow rate of water from the discharge port 13 was about 40 cc / min, and there was no significant difference. Therefore, even if the discharge port 13 is disposed above the introduction port 12 as in the fuel heating device 100, the fuel flow is not hindered thereby. In this experiment, there was almost no influence of convection on the temperature measuring point in the discharge port 13, and there was no temperature rise at this temperature measuring point for 8.5 seconds from the start of energization. However, a configuration in which the temperature inside the discharge port 13 increases during this time may be used.

  In the present invention, the fuel introduction port and the discharge port are not the opening provided on the outer side of the case, but the opening directly communicating with the fuel storage portion where the fuel is heated by the heater. For example, as shown in FIG. 4, in the fuel heating device 102 in which the partition plate 15 is disposed in the case 10 </ b> B, the opening 16 provided on the outer side of the upper portion of the case 10 </ b> B communicates directly with the fuel storage unit 11. It is not a thing and does not correspond to an introduction port. In this case, an opening formed between the lower end portion of the partition plate 15 and the case 10 </ b> B is a portion that directly communicates with the fuel storage portion 11, and this portion substantially becomes the introduction port 12. Therefore, in the case of the configuration shown in FIG. 4, the introduction port 12 can be said to be substantially the same configuration as the embodiment shown in FIG. 1. The above description relates to the introduction port 12, but the same applies to the discharge port 13.

  FIG. 5 shows a fuel heating device 103 which is a modification of the embodiment shown in FIG. 1. As shown in FIG. 5, the heater 20C is inserted and fixed from the lower side of the case 10C. Also good. In this case, it is preferable that the length of the heater 20 is made shorter than that shown in FIG. 1 so that the highest heat generating portion center 22 is located on the lower side (bottom side) of the case 10.

  FIG. 6 illustrates a modification of the case 10 of the embodiment described in FIG. 1 when viewed from the axial direction of the case 10. As shown in FIG. 6, when the introduction port 12 and the discharge port 13 are provided in the case 10, the introduction port 12 and the discharge port 13 are located at positions facing each other across the axis (180 ° symmetrical position) in the embodiment of FIG. 1. Although arranged, it is not always necessary to have this positional relationship. That is, the positional relationship between the inlet 12 and the outlet 13 may be a right-angled positional relationship (the relationship between the inlet 12a and the outlet 13 in FIG. 6), as in the relationship between the inlet 12b and the outlet 13. A positional relationship other than a straight line or a right angle may be used. Further, the introduction port and the discharge port are not limited to be provided on the outer peripheral surface of the case 10, and either one may be provided on the bottom surface or the upper surface of the case 10. In FIG. 6, the positional relationship between the inlet 12 and the outlet 13 is shown, and other configurations are omitted. 6 shows the insertion port 14 as the position of the heater 20, the position of the insertion port 14 and the insertion direction of the heater 20 may be changed to the extent that the gist of the present invention is not deviated. .

  In the above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above-described embodiment and the like, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof. In the above-described embodiment, the fuel storage portion is configured by a case having an inner diameter larger than that of the surrounding piping when forming the room. However, in the piping from the fuel supply common piping to the fuel injection device, heating is performed. The same effect as that of the above-described embodiment may be obtained by arranging the produced fuel so that it can be easily convected. In this case, the piping portion can be regarded as a case in the present invention.

  10, 10A, 10B, 10C, 10 '... case, 11 ... fuel storage, 12 ... inlet, 13 ... discharge, 20 ... heater, 21 ... highest heating part, 22 ... highest heat generation Center, 100, 101, 102, 103, 100 '... fuel heating device, 110 ... fuel supply common piping, 111 ... fuel supply individual piping, 120 ... fuel injection device, V ... gravity direction, H ... ... A virtual plane that passes through the center point of heat generation.

Claims (4)

For a case provided with a fuel storage portion capable of storing fuel therein, an inlet for introducing fuel into the fuel storage portion, and a discharge port for discharging the fuel from the fuel storage portion A fuel heating device in which a heater is inserted and fixed, and the fuel in the fuel storage portion is heated by the heater,
The discharge port is disposed in a heating upper region, which is a region above a virtual plane perpendicular to the direction of gravity passing through the center of the highest heat generating portion of the heater, and the introduction port is disposed below the discharge port in the direction of gravity. A fuel heating device. The fuel heating device according to claim 1,
The fuel heating device according to claim 1, wherein the introduction port is disposed in a heating lower region that is a region below the virtual plane. The fuel heating device according to claim 1 or 2,
In the heating of the fuel by the heater, the heating temperature of the highest heating portion is equal to or higher than the boiling point of the fuel. The fuel heating device according to any one of claims 1 to 3,
The fuel heating device according to claim 1, wherein the case has an inner diameter larger than an inner diameter of a pipe connecting the fuel supply common pipe and the fuel injection device.

Images