JP2005098157A - Fuel evaporation promote device and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress HC carbon by effectively evaporating fuel. <P>SOLUTION: A fuel supply device is a fuel vaporization promoting device having an upstream side fuel injection valve, a heater evaporating the fuel injected from the injection valve, a heater tube transferring the heat of the heater to vaporize the fuel passed through the inside thereof, and an air passage supplying air to the injected fuel. The heater mounting surface of the heater tube is formed by press working. The produced amount of the HC carbon can be minimized during warmup operation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a fuel vaporization promoting device and a method for manufacturing the same, and more particularly to a fuel vaporization promoting device that is mounted on an automobile and suitable for reducing exhaust gas when starting an engine and a method for manufacturing the same.

  For example, Japanese Patent Application Laid-Open No. 2002-195136 discloses an intake air control device for reducing hydrocarbons discharged during warm-up operation when an internal combustion engine is started.

JP 2002-195136 A

  However, the above technique has a problem in that the fuel injected from the upstream fuel injection valve used at the time of starting cannot be completely vaporized, so that the fuel that cannot be vaporized adheres to the intake manifold. For this reason, there is a concern that HC carbon may be generated during the warm-up operation by the amount of attached fuel.

  One of the objects of the present invention is to effectively vaporize the fuel injected from the upstream fuel injection valve used at the time of starting, and to suppress the HC carbon generated during the warm-up operation.

  One of the objects of the present invention is to easily manufacture a device capable of effectively vaporizing fuel injected from an upstream fuel injection valve used at start-up and suppressing HC carbon generated during warm-up operation.

  In order to solve the above problems, in the present invention, the fuel supply device includes a fuel vaporization promotion device, and the fuel vaporization promotion device includes an upstream fuel injection valve and a heater that vaporizes the fuel injected by the upstream fuel injection valve. A heater tube for transferring the heat of the heater to vaporize the fuel passing through the inside and an air passage for supplying air to the injected fuel, and the heater mounting surface of the heater tube is formed by press working is there.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel injected from the upstream fuel injection valve used at the time of starting can be vaporized effectively, and the HC carbon generated at the time of warm-up operation can be suppressed.

  According to the manufacturing method of the present invention, it is possible to easily manufacture a device that can effectively vaporize fuel injected from an upstream fuel injection valve used at start-up and suppress HC carbon generated during warm-up operation. .

  The present invention relates to a fuel supply device for an internal combustion engine provided with a downstream fuel injection valve disposed in each cylinder downstream of an intake pipe, the fuel supply device vaporizing an upstream fuel injection valve and fuel injected by the injection valve A fuel injection and vaporization accelerating device comprising: a heater that heats the heater, vaporizes fuel passing through the interior of the heater, and an air passage that supplies air to the injected fuel; This heater mounting surface is achieved by being formed by press working.

  Preferably, the present invention is achieved by forming the heater mounting surface of the heater tube into a polygonal shape and making the inside circular.

  In the present invention, preferably, the heater tube is made of aluminum or an alloy thereof.

  In the present invention, preferably, the heater tube is made of aluminum or an alloy thereof.

  The present invention relates to a fuel supply device for an internal combustion engine provided with a downstream fuel injection valve disposed in each cylinder downstream of an intake pipe, the fuel supply device vaporizing an upstream fuel injection valve and fuel injected by the injection valve A fuel injection and vaporization accelerating device comprising: a heater that heats the heater, vaporizes fuel passing through the interior of the heater, and an air passage that supplies air to the injected fuel; The molding of is one or all of the dimensions larger than the inner dimension of the cylindrical blank, and is expanded using a polygonal mandrel that is the same as the heater mounting surface, and then the heater mounting surface has the same shape. This is achieved by molding the heater mounting surface with a polygonal shaped female die.

  Preferably, the heater mounting surface of the heater tube is formed by press working, and the surface roughness of the surface is set to Ra heater 0.2 μm or less.

  FIG. 1 is an overall configuration diagram of the present invention.

  The internal combustion engine 1 is a known ignition type internal combustion engine using gasoline as fuel. Here, only one cylinder is noted for illustration.

  The internal combustion engine 1 has an ignition plug 3 disposed in a combustion chamber 2 and includes an intake valve 4 that takes in air and mixed air, and an exhaust valve 5 that performs exhaust after combustion. The internal combustion engine 1 includes a water temperature sensor 7 that detects the temperature of the engine coolant 6 and a rotation sensor (not shown) that detects the rotational speed of the engine at the side of the combustion chamber 2 to detect the operating state.

The intake system that takes in the combustion chamber 2 is linked to the air flow sensor 8 that measures the intake air 26 that is sucked through an air cleaner (not shown), and the driver's accelerator pedal operation or the operating state of the internal combustion engine. The electronically controlled throttle valve 10 and the throttle positioning sensor 28, which are attached to the rotating rotating shaft and electrically controlled to open and close, the intake manifold 11, and each cylinder of the internal combustion engine 1 from the intake manifold 11 And an intake port 14 provided with an intake valve 4 and the like.

The flow rate of the intake air 26 and the opening information of the valve portion 29 of the throttle valve 10 measured by the air flow sensor 8 and the throttle positioning sensor 28 are input to the controller 34 and used for detection of the operating state of the internal combustion engine 1 and various controls. Is done.

  The fuel injection device includes a downstream fuel injection valve 12 and an upstream fuel injection valve 13. The downstream fuel injection valve 12 is attached to the intake port 14 so as to inject toward the intake valve 4 of each cylinder downstream of the intake manifold 11.

  The upstream fuel injection valve 13 is attached to the fuel vaporization promoting device 27 and is configured to be introduced into the intake manifold 11 through a branch passage 15 opened downstream of the electronic control throttle valve 10.

  The fuel system includes a fuel tank 16 that stores fuel 24, a fuel pump 17 that pumps fuel 24 from the fuel tank 16, a fuel filter 18, and a pressure regulator 19 that adjusts the pressure of the pumped fuel 24 to a predetermined pressure. , A downstream fuel injection valve 12 that injects fuel into the intake port 14 of each cylinder (# 1, # 2...), And an upstream fuel injection valve 13 that supplies fuel downstream of the throttle valve portion 29. The fuel pipe 35 is connected.

  The exhaust system includes an exhaust port 36 having an exhaust valve 5 for each cylinder, an exhaust manifold 37, an oxygen concentration sensor 20 for measuring the oxygen concentration in the exhaust, a three-way catalytic converter 21 for purifying exhaust, and a muffler. A muffler (not shown) is provided. The oxygen concentration information measured by the oxygen concentration sensor 20 is input to the controller 34 and used for detection of the operating state of the internal combustion engine 1 and various controls.

The three-way catalytic converter 21 simultaneously purifies NOx, CO, and HC exhausted from the internal combustion engine 1 operated near the theoretical air-fuel ratio with a high purification rate.

  The fuel vaporization promotion device 27 is connected to the open branch passage 15 downstream of the electronic control throttle valve 10, and in order to introduce the air measured by the air flow sensor 8 into the fuel vaporization promotion device 27, the electronic control throttle valve The bypass passages 22 and 23 branched from the intake pipe 9 are formed so as to bypass from the upstream side to the downstream side. The bypass passage 22 is an air passage for transporting the fuel 24 injected from the upstream fuel injection valve 13, and the amount of air flowing through the bypass passage 22 is adjusted by a flow rate adjustment valve 25 provided in the middle of the bypass passage 22. doing. The bypass passage 23 is an air assist air passage used for atomizing the fuel 24 sprayed from the upstream fuel injection valve 13.

  In the above configuration, in the combustion chamber 2, a mixture of the fuel 24 and the intake air 26 injected by the upstream fuel injection valve 12 and the downstream fuel injection valve 13 is sucked. The sucked air-fuel mixture is compressed, ignited by the spark plug 3, and burned. Exhaust gas 121 discharged from the internal combustion engine 1 is released from the exhaust system into the atmosphere.

  FIG. 2 is a cross-sectional view of the fuel vaporization promoting device 27 of the present invention.

  The fuel vaporization promotion device 27 includes a body 39 and a heater body 40. The body 39 is mainly provided with an upstream fuel injection valve 13 and a carrier air introduction pipe 47. A bypass passage 22 (not shown) communicates with the carrier air introduction pipe 47, and the carrier air 22a flows in.

The fuel injection valve 13 is fixed to the body 39 by the fuel pipe 37 and the fuel pipe spring 36, and the fuel 24 pumped from the fuel tank 16 by the fuel pump 17 is supplied via the fuel pipe 35. The O-ring 38 seals between the fuel injection valve 13 and the body 39.

  The heater body 40 incorporates a heater, which will be described later, and the heat of the heater is transmitted to the heater tube 55 to which the heater is attached to vaporize the fuel 24 passing through the inside.

As one means for better vaporizing the fuel 24, the fuel 24 may be in contact with the heater tube 55 for a long time, and it is effective to swirl when passing through the interior as indicated by the arrow 120. For this reason, the inner diameter of the heater tube 55 is preferably circular.

  The fuel 24 flows out of the fuel vaporization promoting device 27 as vaporized fuel 30 indicated by white arrows.

  FIG. 3 shows a configuration diagram of the heater tube of the present invention.

In order to dispose the PTC heater 53 on the outer periphery of the heater tube 55, the heater mounting surface 55a of the heater tube 55 has a polygonal shape (preferably pentagonal or hexagonal shape) and a shape having a plane in the axial direction. A heater guide 54 in the form of a slit is arranged on the outer periphery of the slit so as to guide the PTC heater 53 with an insulating member.

  The plate-like heater (ceramic heater) disposed on the outer periphery of the heater tube 55 has upper and lower planar portions as electrodes (upper is a positive pole and lower is a negative pole), and generates heat when current is applied to the upper and lower electrodes.

Further, in the heater of this embodiment, when the temperature reaches a predetermined value or more, the electrical resistance rapidly increases, the current decreases, and the PTC (Positive Temperature) has a characteristic of keeping the temperature constant.
Coefficient Thermistor) heater 53 is used.

  Since the heater mounting surface 55a of the heater tube 55 transfers the heat of the PTC heater 53, the surface state must be smooth. If it is not smooth, air enters the gaps between the bumps and insulates them, so that heat transfer becomes worse.

  In the present invention, a smooth surface formed by press working (in the present invention, the surface roughness Ra is 0.2 μm or less) is adopted for the heater mounting surface 55a to enhance the heat transfer effect of the heater. As a result, the fuel 24 injected from the upstream fuel injection valve 13 is quickly and almost vaporized, so that the amount of HC carbon in the exhaust 42 produced by combustion in the internal combustion engine 1 can be reduced. Further, since the temperature of the intake fuel is high, the exhaust gas also becomes high temperature, and the temperature of the three-way catalytic converter 21 is increased, so that the generation of HC carbon can be minimized during the warm-up operation. Furthermore, since heating and vaporization can be performed in a short time, the power consumption of the PTC heater 53 can be reduced, and the load on the battery serving as the power source can be reduced.

  The heater mounting surface 55a has a polygonal shape because the PTC heater 53 is a flat plate, but may be on an arc as long as the PTC heater 53 can be manufactured on an arc.

  Here, even when the PTC heater 53 becomes cylindrical, the heater tube 55 is not unnecessary. The PTC heater 53 is brittle. That is, there is a possibility of destruction due to engine vibration or the like, and in such a case, the vaporized fuel may be ejected to cause a fire, so that the structure in which the cylindrical PTC heater 53 is similarly attached to the heater tube It becomes.

  Further, since the heater mounting surface 55a is formed by press working, no burrs are generated. Therefore, since there is no quality variation due to deburring, the performance can be secured stably.

  The material of the heater tube 55 is aluminum which is excellent in thermal conductivity and corrosion, high temperature strength (around 200 ° C.), and press workability. In the present invention, A3004 is adopted. Further effects can be obtained by using two or more clad materials.

  In that case, by using a material having high thermal conductivity on the PTC heater 53 side and adopting a metal resistant to corrosion inside the fuel to pass, high performance can be secured stably.

  FIG. 4 shows the relationship between the temperature rise and time of the product of the present invention and the conventional product.

  In the product of the present invention in which the heater mounting surface 55a of the heater tube 55 is pressed and the conventional product in which machining is performed, the temperature of the product of the present invention rises faster at the temperature of the inner diameter surface of the heater tube 55. This is because the heater mounting surface 55a becomes a smooth surface (in the present invention, the surface roughness Ra is 0.2 μm or less) due to press working, so that the amount of air entering is reduced and the heat transfer effect of the heater is enhanced.

  As a result, the fuel injected from the upstream fuel injection valve is quickly and almost vaporized compared to the conventional product, so that the HC carbon in the exhaust gas produced by combustion in the internal combustion engine is small and the temperature becomes high. In order to increase the temperature of the three-way catalytic converter 21, the generation of HC carbon can be minimized during the warm-up operation.

  Furthermore, since it is performed in a short time, the power consumption of the PTC heater 53 can be reduced, and the load on the battery serving as the power source can be reduced.

  FIG. 5 is a diagram comparing the surface roughness of the pressed surface and the machined surface of the present invention.

  As shown by the roughness curve 130, the press-worked surface of the present invention is not concave and convex, but is partially concave.

  This is because the convex / concave surface of the blank to be molded is flattened by press molding, the material of this portion flows into the concave portion, the amount of the concave portion is reduced, and the concave portion remains partially.

  As indicated by the roughness curve 131, the machined surface is periodically uneven.

  Thus, since the press-worked surface of the present invention has a shape with a dent in a flat portion, when the PTC heater is attached, the height of the projection is very small, so the gap that can be attached is only the dent portion. There are few gaps to enter.

  On the other hand, since the machined surface is periodically uneven, when the PTC heater is mounted, the mounting surface of the PTC heater rides on the tip of the convex portion, and even when the surface roughness is the same, compared to the pressed surface of the present invention. The contact area is small, and the gap generated by the mounting is large.

  For this reason, the present invention employs press working as a method of reducing the gap through which air enters, and the heater tube formed by this method has a higher heat transfer effect than the conventional machined product.

  FIG. 6 shows an initial process of a polygonal molding method in which the heater mounting surface 55a of the heater tube 55 of the present invention is flat in the axial direction.

  A cylindrical blank 101 formed from a plate material by drawing (not shown) is pushed into a polygonal mandrel 102 having a circumscribed circle larger than the inner diameter and expanded. At this time, the round cylindrical blank is expanded into a polygonal shape by a dimensional difference.

  FIG. 7 shows the next step of the polygonal molding method in which the heater mounting surface 55a of the heater tube 55 of the present invention is flat in the axial direction.

  A cylindrical blank 103 having an inner diameter expanded into a polygon is taken out of the mandrel and inserted into the next process mandrel 104. Here, there is a dimensional relationship of mandrel 102> next process mandrel 104.

  The forming female mold 105 having the same shape as the heater mounting surface 55a is lowered to mold the heater mounting surface 55a.

  As described above, the outer diameter shape finished product 106 of the heater mounting surface 55 is completed in a polygonal shape that is a flat surface in the axial direction, which is the heater mounting surface 55a. The inner diameter is finished by machining in the next process.

  FIG. 8 shows the relationship between the heater mounting surface molding load of the heater mounting surface 55a of the present invention and the tube expansion amount in the first step.

  Polygon circumscribed circle = cylindrical blank, inner diameter polygon circumscribed circle> cylindrical blank inner diameter> polygon inscribed circle, polygon inscribed circle = cylindrical blank inner diameter The forming load of the polygon forming load is lowered.

  Thus, the molding load can be reduced, and the molding can be completed without breaking the material during the molding by making the heater mounting surface molding load lower than the tensile strength of the material.

As described above, according to the embodiment of the present invention, the fuel injected from the second fuel injection valve used at the time of starting can be almost vaporized, and the generation of HC carbon can be minimized during the warm-up operation.
Furthermore, the power consumption of the heater is reduced by performing it in a short time.

It is a fuel injection device of an embodiment of the present invention, and a system block diagram carrying this. It is a block diagram of the fuel vaporization promotion apparatus in embodiment of this invention. It is a figure of the heater part. It is a figure of the heater tube inner surface temperature and temperature rising time. It is a surface roughness curve of the product of the present invention and a machined product. (I) to (II) show the tube expansion process, and (III) to (IV) are blank shapes before and after molding. (I) to (II) show the heater mounting surface molding process, and (III) to (IV) are blank shapes before and after molding. The relationship between the heater mounting surface molding load and the initial process pipe expansion amount is shown.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 9 ... Intake pipe, 12 ... Downstream fuel injection valve, 22, 23 ... Bypass passage, 24 ... Fuel, 26 ... Intake air, 27 ... Fuel vaporization promotion apparatus, 53 ... PTC heater, 55 ... Heater tube, 55a ... heater mounting surface, 101 ... cylindrical blank, 102 ... mandrel, 105 ... molded female mold.

Claims (12)

A fuel supply device for an internal combustion engine provided with a downstream fuel injection valve disposed in each cylinder downstream of an intake pipe,
The fuel supply device includes an upstream fuel injection valve, a heater that vaporizes fuel injected by the upstream fuel injection valve, a heater tube that transfers heat from the heater and vaporizes fuel passing through the heater, and the injected fuel And a fuel injection vaporization accelerating device having an air passage for supplying air to the fuel, wherein the heater mounting surface of the heater tube is formed by pressing. In claim 1,
The fuel supply device according to claim 1, wherein the heater mounting surface of the heater tube has a polygonal shape on the outside and a circular shape on the inside.   2. The fuel supply device according to claim 1, wherein the heater tube is made of aluminum and an alloy thereof. In claim 1,
The heater mounting surface of the heater tube is formed of a cylindrical blank, and one or all dimensions of the diameter of the circumscribed circle of the polygonal shape outside the cylindrical blank are larger than the diameter dimension inside the cylindrical blank, The cylindrical blank is expanded by a polygonal mandrel having the same shape as the heater mounting surface, and the heater mounting surface is formed by a polygonal female die having the same shape as the heater mounting surface. The fuel supply apparatus characterized by the above-mentioned. In claim 4,
The fuel supply device, wherein the heater mounting surface of the heater tube is formed by press working, and the surface roughness of the heater mounting surface is Ra 0.2 μm or less.   An upstream fuel injection valve, a heater that vaporizes the fuel injected by the upstream fuel injection valve, a heater tube that transfers heat from the heater and vaporizes the fuel that passes through the heater, and supplies air to the injected fuel A fuel injection and vaporization accelerating device comprising: an air passage for performing fuel injection, wherein the heater mounting surface of the heater tube is formed by pressing. In claim 6,
A fuel injection and vaporization accelerating device characterized in that the heater mounting surface of the heater tube has a polygonal shape on the outside and a circular shape on the inside.   7. The fuel injection and vaporization accelerating device according to claim 6, wherein the heater tube is made of aluminum and an alloy thereof. In claim 6,
A cylindrical blank is formed in the heater tube, and one or all dimensions of the diameter of the circumscribed circle of the polygonal shape outside the cylindrical blank are larger than the dimension of the diameter of the circle inside the cylindrical blank, The tubular blank is expanded by a polygonal mandrel having the same shape as the heater mounting surface, and the heater mounting surface is formed by a polygonal female die having the same shape as the heater mounting surface. The fuel-injection vaporization promotion apparatus characterized by the above-mentioned. In claim 9,
The fuel injection vaporization accelerating device, wherein the heater mounting surface of the heater tube is formed by press working, and the surface roughness of the heater mounting surface is Ra 0.2 μm or less. A method for manufacturing a fuel injection vaporization promoting device, comprising:
The fuel injection and vaporization accelerating device is injected with an upstream fuel injection valve, a heater that vaporizes fuel injected by the injection valve, a heater tube that transfers heat from the heater and vaporizes fuel passing through the heater, An air passage for supplying air to the fuel,
The heater tube is formed by making one or all of the dimensions larger than the dimensions inside the cylindrical blank,
Tube expansion molding using a polygonal molding mandrel that is the same as the heater mounting surface for mounting the heater on the heater tube,
A method for manufacturing a fuel vaporization promoting apparatus, comprising forming a heater mounting surface with a polygonal female die having the same shape as the heater mounting surface. In claim 11,
A method for producing a fuel vaporization promoting device, wherein the heater mounting surface of the heater tube is molded by press working, and the heater tube is molded with a surface roughness of the heater mounting surface of Ra 0.2 μm or less.

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