JP2004138012A - Fuel vaporization accelerator and internal combustion engine equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small size fuel vaporization accelerator capable of increasing fuel vaporization amount without increasing heater capacity and heater heat transfer area in a fuel vaporization accelerator for an internal combustion engine in which further improvement of fuel vaporization capacity is required at the heat transfer surface when fuel injection quantity from a fuel injection valve is increased. <P>SOLUTION: A flanged restrictor 220b is provided on the heat transfer surface 76 as an auxiliary passage 75 in the fuel vaporization accelerator 100. Consequently, thickness of fuel film can be almost equal and a contact surface of the heater heat transfer surface and the fuel film can be increased, resident time of the fuel film 106 injected to the heat transfer surface 76 on the heat transfer surface 76 can be increased, and quantity of heat transferred to the fuel film 106 from the heat transfer surface can be increased. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a fuel vaporization promotion device for an internal combustion engine for a vehicle and an internal combustion engine equipped with the same, and relates to a technique suitable for increasing the amount of fuel vaporization in the fuel vaporization promotion device.
[0002]
[Prior art]
As means for improving the startability of an internal combustion engine, purifying exhaust gas, and particularly reducing HC, it is effective to atomize and vaporize fuel spray injected by a fuel injection valve (injector) to the internal combustion engine. 2. Description of the Related Art It is known to provide a fuel injection valve (injector) which is used mainly at the time of starting an internal combustion engine or the like in order to supply atomized and vaporized fuel spray to the internal combustion engine. For example, a cold start fuel control system including a cold start fuel injector, a heater, and an idle speed control valve (hereinafter, referred to as an ISC valve) is known (for example, see Patent Document 1).
In this system, mixing is promoted by swirling the spray injected from a fuel injection valve disposed downstream of the ISC valve of the internal combustion engine and the intake air passing through the ISC valve, and the fuel mixture that is promoted is mixed with the fuel. The fuel is vaporized by colliding with a cylindrical heater disposed downstream of the injection valve. By rotating the fuel on the inner peripheral surface of the cylindrical heater, the residence time of the spray in the heater section is extended, and the amount of fuel vaporization is increased.
[Patent Document 1]
U.S. Pat. No. 5,894,832 (5th column, FIG. 2).
[0003]
[Problems to be solved by the invention]
As described above, in the conventional system described above, the swirling is applied to the intake air to promote the mixing of the spray and the intake air, and the spray is swirled and collided with the heater disposed downstream of the fuel injection valve to increase the residence time. To increase the amount of fuel vaporized.
[0004]
Here, in an internal combustion engine having a large displacement, the fuel injection amount from the fuel injection valve increases. Therefore, on the heat transfer surface of the heater, it is necessary to improve the fuel vaporization ability corresponding to the increase in the injection amount. As a countermeasure, measures such as an increase in the heater capacity and an increase in the area of the heat transfer section can be given. However, in the case of these countermeasures, the power consumption of the heater heat transfer section is increased and the size of the apparatus is increased, so that the mountability to the internal combustion engine must be separately considered.
[0005]
SUMMARY OF THE INVENTION It is an object of the present invention to increase the amount of heat transferred from a heater to fuel and to increase the amount of fuel vaporized by providing a means for significantly increasing the time that fuel stays on a heater heat transfer surface with a simple structure. It is.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, at least one throttle is provided on a heater heat transfer surface disposed downstream of a fuel injection valve mainly used at the time of starting or the like, or downstream thereof. Was provided. On the inner peripheral portion of the throttle, a projection is formed that projects to both or one of the upstream and downstream sides in the axial direction of the heat transfer section. By disposing the throttle provided with the protrusions in the heat transfer section, the fuel liquid film can be made to have a substantially uniform thickness, and the contact area between the heater heat transfer surface and the fuel liquid film can be increased. , The amount of heat transferred from the heat transfer surface to the fuel spray can be increased, so that the amount of fuel vaporized can be increased. As a result, the number of heaters can be reduced, and downsizing of the heater section can be realized.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described below with reference to FIGS.
[0008]
In FIG. 1, an internal combustion engine 1 is a well-known ignition type internal combustion engine using gasoline as a fuel, but only one cylinder is shown.
[0009]
The internal combustion engine 1 has an ignition plug 3 disposed in a combustion chamber 2 and an intake valve 4 for taking in a mixed air of air and gasoline and an exhaust valve 5 for exhausting after combustion. The internal combustion engine 1 is provided with a water temperature sensor 7 for detecting the temperature of the engine cooling water 6 and a rotation sensor (not shown) for detecting the number of revolutions of the engine on the side of the combustion chamber 2 to detect the operating state.
[0010]
An intake system that intakes air into the combustion chamber 2 includes an air flow sensor 8 that measures the amount of intake air 26 that is sucked through an air cleaner (not shown) and a driver operating an accelerator pedal or operating the internal combustion engine. An electronically controlled throttle valve 10 that electrically controls the amount of intake air by a valve unit 131 that is attached to a rotating shaft 134 that rotates in conjunction with the opening and closing, a throttle positioning sensor 130, an intake manifold 11, and an intake manifold An intake manifold 39 branching from 11 to each cylinder of the internal combustion engine 1 and an intake port 14 having an intake valve 4 are provided.
[0011]
The flow rate of the intake air 26 measured by the airflow sensor 8 and the opening information of the valve portion 131 of the throttle valve 10 measured by the throttle positioning sensor 130 are input to the controller 35 to detect the operating state of the internal combustion engine 1 and perform various controls. Used for
[0012]
The fuel system includes a fuel tank 16 for storing the fuel 24, a fuel pump 17 for pumping the fuel 24 from the fuel tank 16, a fuel filter 18, and a pressure regulator 19 for adjusting the pressure of the fed fuel 24 to a predetermined pressure. , A fuel injection valve 12 for injecting fuel into an intake port 14 of each cylinder (# 1, # 2,...), And a fuel injection valve 13 for supplying fuel downstream of a valve section 131. Connected.
[0013]
The fuel injection device includes a fuel injection valve 12. The fuel injection valve 12 is disposed in the intake port 14 so as to inject the fuel toward the intake valve 4 of each cylinder downstream of the intake manifold 11.
[0014]
The fuel vaporization accelerating device 100 is provided with a fuel injection valve 13. The fuel vaporization accelerating device 100 is connected to a branch passage 15 opened on the downstream side of the electronic control throttle valve 10 so that fuel injected from the fuel injection valve 13 is supplied to the intake manifold 11 as vaporized fuel. Have been. The bypass passage 22 branched from the intake pipe 9 bypasses the amount of intake air 26 measured by the air flow sensor 8 from upstream to downstream of the electronic control throttle valve 10 so as to be introduced into the fuel vaporization promoting device 100. 23 are formed. The bypass passage 22 is an air passage for conveying the fuel 24 injected from the fuel injection valve 13. Further, the amount of air flowing through the bypass passage 22 is adjusted by a flow control valve 25 provided in the middle of the bypass passage 22. The bypass passage 23 is an air passage for air assist used for atomizing the fuel 24 injected from the fuel injection valve 13.
[0015]
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 the exhaust, and a silencer. It is composed of a muffler (not shown) and the like. The oxygen concentration information measured by the oxygen concentration sensor 20 is input to the controller 35 and used for detecting 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 stoichiometric air-fuel ratio at a high purification rate.
[0016]
In the internal combustion engine 1 having the above configuration, a mixture 40 of the fuel spray injected by the fuel injection valves 12 and 13 and the intake air 26 is sucked into the combustion chamber 2. The air-fuel mixture 40 sucked into the combustion chamber 2 is compressed, ignited by the ignition plug 3, burns, and is discharged as the exhaust gas 42 to the outside of the internal combustion engine 1.
[0017]
Here, the relationship between the amount of harmful exhaust gas discharged from the internal combustion engine 1 in the state of fuel spray supplied to the combustion chamber 2 of the internal combustion engine 1 will be described with reference to FIG.
[0018]
FIG. 2A shows the difference in the average particle diameter of the fuel spray and the limit of the ignition timing that indicates how much the ignition timing can be delayed (retarded) while maintaining the stability of combustion when the vaporized fuel is supplied. It is a figure showing a relation. As shown in the figure, if the fuel 33 is supplied to the combustion chamber 2 of the internal combustion engine 1 in a state where the particle diameter of the fuel spray is small, preferably in a completely vaporized state, the combustion can be stabilized. The ignition timing can be largely retarded until the expansion stroke starts. When ignition is performed in the expansion stroke, the rate of expansion of the combustion gas in the combustion chamber is reduced, so that the amount of heat consumed by the combustion gas by the expansion work can be reduced, and the combustion gas can be discharged to the exhaust manifold 39 while maintaining a high temperature. . In other words, as shown in FIG. 2B, the catalyst 21 can be quickly warmed up by retarding the ignition timing and discharging the high-temperature combustion gas. The time until 21 reaches the activation temperature can be shortened. That is, as shown in FIG. 2C, since the purifying action of the catalyst 21 is started at an early stage, the amount of HC discharged after the start of the internal combustion engine 1 can be significantly reduced. The early warm-up of the catalyst (three-way catalytic converter) 21 can reduce not only HC but also NOx and CO. As described above, promoting the vaporization of the fuel spray supplied to the internal combustion engine 1 is an effective means for purifying the exhaust gas of the internal combustion engine 1.
[0019]
Next, the configuration of the fuel vaporization promoting device 100 will be described with reference to FIGS.
[0020]
FIG. 3A is an external perspective view of the fuel vaporization promoting device 100. The main external configuration of the fuel vaporization accelerating device 100 is composed of a body 102 and a heater body 101, and the body 102 is mainly provided with a fuel injection valve 13, a conveying air introduction pipe 30, and an atomizing air introduction pipe 31. Has been established. The bypass passage 22 communicates with the carrier air introduction pipe 30, and carrier air 22 a, which is a part of the intake air 26, flows in. The bypass passage 23 communicates with the atomized air introduction pipe 31, and the atomized air 23 a, which is a part of the intake air 26, flows in. Then, the fuel is supplied to the fuel injection valve 13 from the fuel tank 16 by the fuel pump 17, and the fuel 24 is supplied through the fuel pipe 38.
[0021]
The heater body 101 has a built-in heater described later, and is provided with positive and negative electrode terminals 28 and 29 for energizing the heater. The fuel 24 vaporized by the heater in the heater body 101 flows out of the fuel vaporization accelerating device 100 as vaporized fuel indicated by an arrow 33 and is supplied to the intake manifold 11 through the branch passage 15.
[0022]
Next, the internal configuration of the fuel vaporization promoting device 100 will be described. FIGS. 3 (b) and 3 (c) show views in the directions of arrows A and B in FIG. 3 (a). FIG. 4 is a sectional view taken along line DD in FIG. FIG. 5 is a cross-sectional view taken along the line CC in FIG. FIG. 6 is an enlarged sectional view of a portion E in FIG.
[0023]
FIG. 4 is a cross-sectional view of the body 102 of the fuel vaporization accelerating device 100, which is a cross-section taken along line DD in FIG. The body 102 is provided with a conveyance air introduction pipe 30 and an atomization air introduction pipe 31, and the conveyance air introduction pipe 30 communicates with a pressure regulation chamber 50 inside the body 102. A swirling nozzle 51 is provided in the pressure adjustment chamber 50. The transport air introduction pipe 30 is arranged so as to be offset by a distance L from the center axis of the pressure regulating chamber 50 in the cross section in the drawing. Therefore, the carrier air 22 a passing through the carrier air introduction pipe 30 is introduced to a position offset from the center axis of the cross section of the pressure regulation chamber 50.
[0024]
In the swirl nozzle 51, fins 58 having a plurality of blade cross-sectional shapes are formed at equal intervals circumferentially, and the passage cross-sectional area formed between the fins 58 is the passage cross-sectional area on the inlet side of the conveying air 22a. And the cross-sectional area of the outlet-side passage is narrow. In addition, the cross-sectional area of the passage of the pressure regulating chamber 50 is formed in a swirl shape that gradually decreases as going downstream so that the flow velocity of the carrier air flow 52 passing between the fins 58 becomes constant. The swirl shape is a structure in which the outer diameter of the pressure regulation chamber 50 is constant and the depth in the fuel injection axial flow direction is gradually reduced, so that the swirl structure can be adopted in a limited space. It is.
[0025]
A mixing chamber 56 is formed in the inner circumferential direction of the cross section of the swirl nozzle 51 in the drawing. An air atomizer 55 is provided upstream of the mixing chamber 56. An air atomizer injection hole 54 is formed in the air atomizer 55. The fuel injection valve 13 is disposed upstream of the injection hole 54. The injection hole 57 of the fuel injection valve 13 and the air atomizer injection hole 54 are disposed so as to be substantially concentric. The atomized air introduction pipe 31 communicates with the air atomizer injection hole 54. Therefore, the fuel spray injected from the fuel injection valve 13 is supplied to the mixing chamber 56 through the air atomizer injection hole 54 while being atomized by the atomized air 23 a having passed through the atomized air introduction pipe 31. The detailed configuration on the upstream side of the air atomizer 55 will be described later with reference to FIG.
[0026]
FIG. 5 is a cross-sectional view taken along the line CC in FIG. A sub-passage 75 is formed inside the heater body 101 attached to the branch passage 15 opened downstream of the electronic control throttle valve 10, and a plate-shaped heater 77 is provided around the sub-passage 75. I have. The heater 77 generates heat by applying current to the upper and lower electrodes, and the upper and lower flat portions serve as electrodes. Further, when the temperature of the heater 77 is equal to or higher than a predetermined temperature, the electric resistance suddenly increases and the current decreases, so that the temperature can be kept constant. The positive temperature coefficient PTC (Positive Temperature Coefficient Thermistor) is a ceramic heater. A heater is used.
[0027]
The sub-passage 75 separates the space in which the heater 77 and the like are housed by the O-ring 74 and the gasket 72. The gasket 72 is compression-sealed so as to be sandwiched between the heater body 101 and the body 102.
[0028]
A plurality of upstream flanged throttles 220b are press-fitted and fixed in the sub-passage 75 at a predetermined interval Lp along the passage axial flow direction. Details will be described later with reference to FIG.
[0029]
The body 102 has a fuel injection valve 13 disposed coaxially with the heater body 101. The fuel injection valve 13 is press-fitted and fixed to a case 70 having an air introduction hole, and an O-ring 84 and an O-ring 84. At 90, the body 102 is positioned so as to seal the internal passage, and is fixed to the body 102 by the fuel pipe 34 and the fuel pipe fly 83. The atomizing air introduction pipe 21 communicates with an atomizing air pressure regulating chamber 71 formed on the outer periphery of the case 70 and a part of the inner peripheral surface of the body 102, and the pressure regulating chamber 71 has an air introducing hole formed in the case 70. Through the space formed by the outer peripheral surface of the fuel injection valve 13 and the inner peripheral surface of the case 70. The space communicates with a mixing chamber 56 through an injection hole 54 formed in an air atomizer 55. The fuel passage is sealed by disposing an O-ring 73 between the fuel pipe 34 and the fuel injection valve 13. A swirling nozzle 51 is disposed downstream of the air atomizer 55 in the injection direction of the fuel injection valve 13.
[0030]
FIG. 6 is an enlarged sectional view of a portion E in FIG. In the vicinity of the PTC heater 77, an inner cylinder 200 is disposed on the inner peripheral surface side of the heater body 101 via an air layer 105 in a predetermined space in consideration of a heat insulating effect. An elastic member 78 made of an insulating elastic material is disposed on the inner peripheral surface of the inner cylinder 200 in surface contact. On the inner surface of the elastic member 78, a brass electrode plate 79 is disposed in surface contact. The PTC heater 77 is in surface contact with the inner surface of the positive electrode plate 79. The inner surface of the PTC heater 77 is in surface contact with the outer peripheral surface of the heat transfer surface 76 forming the sub passage 75. Here, the heat transfer surface 76 is an inner surface of the heat transfer member 89 that forms the sub passage 75 that is in contact with the PTC heater 77, and a surface that actively transmits heat from the PTC heater 77 into the sub passage 75. It is.
[0031]
Further, the positive electrode plate 79 is connected to the positive electrode terminal 28 outside the heater body 101 via the electrode portion 80. On the other hand, the conductive heat transfer member 89 is press-fitted and fixed to the electrode portion 82 and connected to the negative electrode terminal 29 outside the heater body 101.
[0032]
Due to these structures, as shown in FIGS. 3, 5 and 6, conduction is established from the positive electrode terminal 28 to the electrode portion 80, the positive electrode plate 79, the PTC heater 77 and the heat transfer member 89, and the electrode portion 82 and the negative electrode terminal 29. It has a configuration. Therefore, when a current is applied to the above-described electrode terminals 28 and 29, a current is applied from the positive electrode plate 79 to the heat transfer member 89 via the PTC heater 77, and the PTC heater 77 generates heat and heat is transferred. This structure heats the member 89 and the heat transfer surface 76. The electrode unit 80 and the electrode unit 82 are configured to be insulated by an insulating member 81.
[0033]
Further, the upstream flanged throttle 220b provided in the sub-passage 75 has a throttle shape that changes the passage cross-sectional area of the sub-passage 75. Further, a continuous flange-shaped projection is formed on the inner peripheral portion of the aperture 220b. The protrusion has a shape with an upstream flange that protrudes upstream in the axial flow direction of the heat transfer surface 76 of the sub passage 75. A plurality of the upstream flanged throttles 220b are formed at a predetermined interval Lp in the axial flow direction of the heat transfer surface 76 of the sub passage 75 in the shape of the outer diameter φD, the diameter φd of the throttle, and the height H of the projection. I have. That is, in this embodiment, as in the other embodiments described later, the inner peripheral surface of the flange-shaped projection forms a cylindrical surface parallel to the axial flow direction.
[0034]
Next, the flow of intake air of the internal combustion engine 1 provided with the fuel vaporization promoting device 100 having the above configuration will be described. In the present embodiment, when the internal combustion engine 1 is operated, a pressure difference occurs upstream and downstream of the valve portion 131 of the electronically controlled throttle valve 10. Therefore, when the opening degree of the valve portion 131 of the electronically controlled throttle valve 10 is small or completely closed, the intake air flows into the air passages 22 and 23 bypassing the electronically controlled throttle valve 10. Here, the fuel vaporization promoting device 100 is configured in the bypass passage. Therefore, the fuel spray 85 injected from the fuel injection valve 13 provided in the fuel vaporization accelerating device 100 is atomized because the atomized air 23a passes through the air atomizer 55 and turns and collides. The atomized fuel spray is supplied from the air atomizer injection hole 54 to the mixing chamber 56 downstream of the injection hole 54 as a fuel spray 85 which is a mixture of the fuel spray and the atomized air 23a.
[0035]
Further, the carrier air 22 a bypassed by the bypass passage 22 from the carrier air introduction pipe 30 passes through the space between the respective fins 58 formed in the swirling nozzle 51 and is supplied to the mixing chamber 56 at a uniform flow rate as the carrier air flow 52. You. The carrier air flow 52 supplied to the mixing chamber 56 becomes a swirling flow 86 of the intake air in the mixing chamber 56. When the fuel spray 85 collides with the swirling flow 86, the fuel spray 85 collides with the heat transfer surface 76 substantially uniformly at the position of the same cross section in the axial flow direction. The colliding fuel spray 85 passes through the heat transfer surface 76 of the sub-passage 75 downstream of the mixing chamber 56 along the swirling flow 86 as a fuel liquid film 106 on the heat transfer surface 76.
[0036]
Here, a throttle 220b with an upstream flange is provided on the heat transfer surface 76 of the sub passage 75, and a predetermined amount of the fuel liquid film 106 is retained by a step formed by the inner diameter ΦD of the heat transfer surface 76 and the inner diameter Φd of the throttle 220b. It is possible to prevent the fuel from flowing out of the fuel vaporization promoting device 100.
[0037]
Further, in the fuel vaporization accelerating device 100 provided with the upstream flanged throttle 220b, the fuel liquid film 106 swirls in the cylindrical heat transfer surface 76 of the sub passage 75 along the intake air swirl flow 86. The heat transfer surface 76 moves to the downstream side in the axial flow direction. The intake air swirl flow 86 and the fuel liquid film 106 have a velocity component in the axial flow direction (X direction) and a velocity component in the swirl direction (Y direction). Here, by disposing the upstream flanged throttle 220b on the heat transfer surface 76 of the sub passage 75, the axial flow component of the fuel liquid film 106 moving on the heat transfer surface 76 is converted into a swirl direction component. In other words, since the axial flow velocity component is small and the swirl velocity component is large, the number of swirling flows of the intake air swirl flow 86 and the fuel liquid film 106 flowing along the swirl flow 86 can be increased, and The time during which the fuel liquid film 106 stays can be greatly increased. Further, since the cross-sectional area in the axial flow direction of the sub-passage 75 changes by the upstream flanged throttle 220b, a flow stagnation region can be formed, so that the fuel liquid film 106 can be retained.
[0038]
Here, the effect of the present invention will be described with reference to FIG. FIG. 9 is a schematic cross-sectional view showing a state in which fuel liquid films 106a, 106b, and 106c adhere to a heat transfer portion due to a throttle shape provided in a sub passage 75. FIG. 7A shows a case where the flat plate stop 220a is disposed on the heat transfer surface 76 of the sub passage 75. FIG. 7B shows a case where the upstream flanged stop 220b is disposed on the heat transfer surface 76 of the sub passage 75. FIG. 7C shows a case where the downstream flange 220b is disposed on the heat transfer surface 76 of the sub passage 75. In this schematic diagram, a portion corresponding to the heater body 101 is made of transparent acrylic in order to visualize the fuel liquid films 106a, 106b, and 106c staying on the heat transfer surface 76 of the sub passage 75, and is drawn based on the visualization result. I have.
[0039]
In the case of the flat plate throttles, in the regions (1), (2), and (3) surrounded by dotted lines on the heat transfer surface sandwiched between the flat plate throttles, the region (1) has the largest fuel liquid film. 106a tends to stay and then stays in the area (3). The retention of the fuel liquid film 106a in the area (2) tends to be relatively small. These factors are due to the fact that the stagnation (residence) area of the fuel liquid film 106a is formed in the area (1) immediately before the narrowing because the passage cross-sectional area is reduced by the narrowing of the flat throttle 106a. Further, in the region (3), the passage liquid cross-sectional area is enlarged via the throttle 220a, and the stagnation (residence) region is formed in the region (3), so that the fuel liquid film 106a is stagnant (remains).
[0040]
On the other hand, in the case of the upstream flanged throttle 220b in FIG. 7 (b), the swirl air flow 106 having the X-direction component flows into the outer circumference of the flange by using the upstream flanged throttle 220b, and the fuel liquid in the area (1) The film 106b is displaced, the fuel liquid film is dispersed, and the liquid film 106b moves to the area (2). Thereby, the fuel liquid film in contact with the heat transfer surface is enlarged as compared with the case of the flat plate throttle. Therefore, the time during which the fuel liquid film 106 stays on the heat transfer surface 76 can be greatly increased. Therefore, the amount of heat transmitted from the heat transfer surface 76 to the fuel liquid film 106 can be increased, the vaporization of fuel can be promoted, and the amount of vaporization can be increased. That is, approximately the same amount of the fuel liquid film 106b stays in the areas (1) and (3), and relatively stays in the area (2). Further, in the area (2), a large amount of stagnation occurs in comparison with the area (2) of the flat plate stop 220a in FIG. This is because the degree of stay of the fuel liquid film 106 is compared with that of the flat plate 220a in FIG. 7A, and the fuel liquid film 106b is dispersed and stays on the heat transfer surface 76 without being concentrated. This is because the amount of the fuel liquid film 106 staying in the area (1) in the figure (b) is smaller than that in the flat plate drawing in the figure (a).
[0041]
In the case of the throttle 220c with the downstream flange shown in FIG. 7C, the fuel liquid film 106c tends to stay most in the area (3), and then stays in the area (1). The retention of the fuel liquid film 106c in the region (2) tends to be small. This is because the stagnation area due to the passage cross-sectional area being enlarged through the throttle and the stagnation area at the outer circumference of the collar are shown in (a) and (b) of FIG. This is because the fuel liquid film 106c was concentrated because it was formed larger. Therefore, in the areas (1) and (2), the fuel liquid film 106c tends to be relatively small.
[0042]
From the above results, it can be said that, when comparing the various throttles of FIGS. 7A, 7B, and 7C, the upstream flanged throttle 220b is the most preferable for dispersing the fuel on the heat transfer surface.
[0043]
Further, in order to vaporize the fuel liquid film 106 staying on the heat transfer surface 76 at an early stage and to increase the amount of vaporization, the heat generated from the PTC heater 77 is efficiently transmitted and the temperature on the heat transfer surface 76 is increased. It is preferable to reduce the time. For this purpose, it is preferable to reduce the heat capacity of the heat transfer member 89 constituting the heat transfer surface 76. Therefore, it is desirable to keep the heat transfer area of the heat transfer member 89 as thin as possible. However, when the thickness of the heat transfer member 89 is reduced, the strength of the heat transfer member 89 decreases. Here, by arranging the upstream flanged throttle 220b on the heat transfer surface 76 of the sub-passage 75 formed by the heat transfer member 89, the strength of the heat transfer member 89 can be improved, and a highly reliable fuel vaporization device can be provided. 100 can be provided.
[0044]
As described above, by disposing the upstream flanged throttle 220b in the sub-passage 75, the vaporization of the fuel liquid film 106 supplied from the fuel injection valve 13 can be promoted, and at the same time, the fuel flowing out of the fuel vaporization promoting device 100 can be improved. Generation of a liquid flow can be suppressed. In other words, by increasing the time during which the fuel liquid film 106 stays on the heat transfer surface 76, the amount of fuel vaporized can be increased. That is, since the residence time can be extended and the same amount of fuel is vaporized, the PTC heater 77 having a small heat generation capacity (number of sheets) can be realized, so that the small-sized fuel vaporization promotion device 100 can be realized. Further, since the thickness of the members forming the heat transfer surface 76 can be reduced while maintaining the strength of the members forming the heat transfer portion 76, the heat capacity can be reduced, and the time for raising the temperature of the heat transfer surface 76 can be reduced. Can be.
[0045]
FIG. 8A shows the results obtained by plotting the brim height H of the throttle on the horizontal axis and the residence time during which the fuel liquid film 106 stays in the heat transfer section on the vertical axis. Here, the heat transfer section residence time was measured by visualizing the flow of the fuel liquid film 106 passing through the inside of the acrylic pipe with the heat transfer surface 76 serving as a transparent acrylic pipe. FIG. 8B shows the result obtained by taking the flange height H of the throttle on the horizontal axis and arranging the fuel vaporization rate on the vertical axis. This result shows the effect of the vaporization rate by the flange height H of the throttle under the same predetermined conditions using the fuel vaporization accelerating device 100 described in the present embodiment. From this result, in FIG. 8A, the residence time of the fuel liquid film 106 in the heat transfer section can be increased by increasing the brim height H. Here, the brim height “0” represents a flat plate drawing, and the residence time of the heat transfer section can be increased by making the brim height H higher than that of the flat plate drawing. For example, in the case of a throttle with an upstream flange, when the flange height H is set to 0 mm and 6.5 mm, the residence time is 1.4 seconds and 4.0 seconds. The residence time was increased three times. Also, the residence time of the upstream flanged throttle tends to be longer than that of the downstream flanged throttle.
[0046]
Next, in FIG. 8B, the vaporization rate tends to increase by increasing the brim height H. For example, in the case of a throttle with an upstream flange, when the flange height H is 0 mm and 6.5 mm, the fuel vaporization rate is improved by about 10%. Further, the tendency is the same as the result of (a), and the improvement in the vaporization rate of the upstream flanged throttle is greater than that of the downstream flanged throttle. This is because the residence time of the fuel liquid film 106 passing through the heat transfer surface is long, and the amount of heat transferred from the heat transfer surface 76 to the fuel liquid film 106 can be increased. Further, the difference may be caused by the difference in the formation of the fuel liquid films 106a, 106b, and 106c on the heat transfer surface 76 in FIG.
[0047]
Therefore, by using the throttle with a flange, the amount of fuel vaporized can be increased when the heat generation capacity (number of sheets) of the PTC heater 77 is the same. Therefore, when promoting the vaporization of the fuel liquid film 106 having the same flow rate, the number of the PTC heaters 77 can be reduced. Therefore, downsizing of the fuel vaporization promoting device 100 can be realized.
[0048]
By using the internal combustion engine 1 including the fuel vaporization promoting device 100 described above, the amount of heat transmitted from the heater to the fuel can be increased, and the amount of fuel vaporized can be increased. Therefore, a small fuel vaporization promoting device can be provided without increasing the heater capacity and the heater heat transfer area. Further, it is possible to provide a fuel vaporization accelerating device for an internal combustion engine for an automobile, which can improve the startability of the internal combustion engine for an automobile, improve fuel efficiency and reduce exhaust gas purification, and an internal combustion engine equipped with the same.
[0049]
A second embodiment of the present invention will be described with reference to FIG.
[0050]
The main difference from the fuel vaporization accelerating device 100 of the first embodiment lies in the mounting position of the collar of the throttle provided on the heat transfer surface 76 of the sub passage 75. That is, a continuous flange-shaped projection is formed on the inner peripheral portion of the throttle 220c, and this projection is the downstream flanged throttle 220c that protrudes downstream in the axial flow direction of the heat transfer surface 76 of the auxiliary passage 75. . Further, in the present embodiment, the bypass passage 23 and the atomized air introduction pipe 31 are eliminated by not using the atomized air 23a for promoting atomization of the fuel spray 85a injected from the fuel injection valve 13. The other configuration is the same as that of the first embodiment, and the description is omitted.
[0051]
In this embodiment, the downstream sprayed throttle 220c is disposed on the heat transfer surface 76 of the auxiliary passage 75, so that the fuel spray 85a injected from the fuel injection valve 13 stays on the heat transfer surface 76 as the fuel liquid film 106. It becomes possible. The distribution, residence time, and vaporization rate of the fuel liquid film 106 on the heat transfer surface 76 have been described with reference to FIGS. 7C and 8 described above. Thereby, the distribution of the fuel liquid film 106b, the residence time, and the vaporization rate can be improved as compared with the flat plate throttle 220a having no brim height. Therefore, the amount of heat transmitted from the heat transfer surface 76 to the fuel liquid film 106 can be increased, and the amount of fuel vaporized can be increased.
[0052]
A third embodiment of the present invention will be described with reference to FIG.
[0053]
The main difference from the fuel vaporization accelerating device 100 of the first embodiment lies in the mounting position of the collar of the throttle provided on the heat transfer surface 76 of the sub passage 75.
[0054]
That is, a continuous flange-shaped projection is formed on the inner peripheral portion of the throttle 220d, and the projection is the upstream-downstream flanged throttle 220d protruding in both the upstream and downstream directions in the axial direction of the heat transfer surface 76 of the auxiliary passage 75. It is in. Further, the atomizing air 23a for promoting atomization of the fuel spray 85a injected from the fuel injection valve 13 is not used. Therefore, the configuration is such that the bypass passage 23 and the atomized air introduction pipe 31 are eliminated. Further, the swivel nozzle 51 is eliminated and the transfer nozzle 53 is provided. As a result, the transport air 22a passes through the swirl nozzle 51, and the fuel spray 85 is swirl-supplied while actively colliding with the heat transfer surface 76 of the sub-passage 75. The transport air 22a is less likely to supply the fuel spray 85a by swirling on the heat transfer surface 76 of the sub-passage 75, and the transport air flow 86b is supplied along the axial direction of the heat transfer surface 76b. The other configuration is the same as that of the first embodiment, and the description is omitted. Here, the fuel injection valve 13 is provided with a fuel swirling member for swirling and injecting fuel at an upstream side of a valve seat located upstream of the injection hole 57 of the fuel injection valve 13 having excellent atomization characteristics. It is an upstream swirling type fuel injection valve provided. Therefore, the injected fuel spray 85a has a hollow cone-shaped spray shape, and the relatively large droplets in the fuel spray concentrate on the outer periphery of the spray, and the relatively small liquid droplets of which the atomization is promoted are reduced. Drops are sprays that are present at the inner periphery of the spray. Therefore, only the atomized atomized spray in the spray 85 a is positively transported along the transport air flow 86 b supplied via the transport nozzle 53, and is transported and supplied to the combustion chamber 2 of the internal combustion engine 1. In addition, the coarse particles in the spray 85a hardly get on the conveying air flow 86b and adhere to the heat transfer surface 76b. The attached fuel spray becomes the fuel liquid film 106 and stays near the upstream and downstream flanged throttle 220d. Therefore, only relatively large droplets of the fuel spray 85a injected from the fuel injection valve 13 are retained as the fuel liquid film 106 near the upstream and downstream flanged throttle 220d. The outflow of the fuel liquid flow to the outside of 100a can be prevented, and the vaporization of the fuel liquid film can be promoted. Further, since the stagnation (residence) area is wider than the throttles 220a, 220b and 220c described in the first and second embodiments, a larger amount of the fuel liquid film 106 can be retained on the heat transfer surface 76. .
[0055]
Other phenomena and effects are the same as those in the first embodiment, and thus description thereof is omitted.
[0056]
As described above, according to the embodiment of the present invention, in the fuel spray injected and supplied from the fuel injection valve 13, it is necessary to uniformly reduce the droplet diameter of the spray which promotes the atomization on the heat transfer surface. It is preferable to form a liquid film. In the above-described embodiment, the air assist system for promoting atomization by colliding a part of the intake air with the spray has been described as the atomization means for the fuel spray mainly injected from the fuel injection valve 13. The means are not so limited. For example, the present embodiment can be applied by using a high-pressure type fuel injection valve in which the supply pressure of the fuel is increased or a fuel injection valve using an ultrasonic vibration type atomizing means for colliding the fuel with an ultrasonic vibration element. It is.
[0057]
Furthermore, the fuel vaporization promoting device of the present embodiment has been described with respect to the intake port fuel injection system in which the fuel injection valve 12 is disposed at each intake port. However, the present invention is not limited to this, and fuel is directly injected into the combustion chamber 2. This embodiment is also applicable to the in-cylinder fuel injection system.
[0058]
【The invention's effect】
According to the present invention, the fuel liquid film is made to have a substantially uniform thickness by increasing the time for which the fuel stays on the heater heat transfer surface and by providing means for positively dispersing the fuel liquid film staying on the heat transfer surface. Since the contact area between the heater heat transfer surface and the fuel liquid film can be increased, the amount of heat transferred from the heater to the fuel can be increased, the amount of fuel vaporized can be increased, and the heater capacity and heater heat transfer area can be reduced. A small fuel vaporization promoting device can be provided without expansion. Further, it is possible to provide a fuel vaporization accelerating device for an internal combustion engine for an automobile, which can improve the startability of the internal combustion engine for an automobile, improve fuel efficiency and reduce exhaust gas purification, and an internal combustion engine equipped with the same.
[Brief description of the drawings]
FIG. 1 is a configuration diagram showing an embodiment of an internal combustion engine equipped with a fuel vaporization accelerating device according to the present invention.
FIG. 2 is a diagram illustrating a relationship between fuel vaporization, a catalyst temperature, and an amount of HC emission.
3A is a perspective view, FIG. 3B is a front view, and FIG. 3C is a side view of the fuel vaporization promoting device shown in FIG. 1 according to the present invention.
FIG. 4 is a cross-sectional view of the fuel vaporization promoting device DD shown in FIG. 3 (c) according to the present invention.
FIG. 5 is a sectional view of the fuel vaporization accelerating device CC shown in FIG. 3B according to the present invention.
FIG. 6 is an enlarged sectional view of a portion E of the fuel vaporization accelerating device shown in FIG. 4 according to the present invention.
FIG. 7 is a schematic cross-sectional view showing a distribution of a stay of a fuel liquid film in a heat transfer portion by each of the throttle shapes according to the present invention.
FIG. 8 is a diagram showing the relationship between (a) the fuel residence time of the heat transfer section and (b) the fuel vaporization rate according to various throttle shapes of the fuel vaporization promoting device according to the present invention.
FIG. 9 is a sectional view of a fuel vaporization accelerating device according to a second embodiment of the present invention.
FIG. 10 is a sectional view of a fuel vaporization accelerating device according to a third embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Combustion chamber, 9 ... Intake pipe, 11 ... Intake manifold, 12, 13 ... Fuel injection valve, 21 ... Three-way catalytic converter, 22 ... Bypass passage, 22a ... Carrier air, 23a ... Atomization Air, 26 ... intake air, 33 ... vaporized fuel, 50 ... pressure regulating chamber, 51 ... swirling nozzle, 52 ... swirling air flow, 55 ... air atomizer, 56 ... mixing chamber, 75 ... sub-passage, 76 ... heat transfer surface, 86: swirling flow of intake air, 77: PTC heater, 100: fuel vaporization promoting device, 220b: throttle with upstream flange, 220c: throttle with downstream flange, 220d: throttle with upstream and downstream flange.

Claims (6)

Means for rotating air by applying air to the fuel spray injected from the liquid fuel injection valve, and colliding the fuel spray with a heat transfer section disposed downstream of the fuel injection valve to supply the fuel spray to an intake pipe At
A fuel vaporization accelerating device characterized in that a means for extending the time for which fuel injected from the fuel injection valve stays in the heat transfer section and for actively dispersing the fuel liquid film staying on the heat transfer section is provided. . Means for rotating air by applying air to the fuel spray injected from the liquid fuel injection valve, and colliding the fuel spray with a heat transfer section disposed downstream of the fuel injection valve to supply the fuel spray to an intake pipe At
At least one throttle is provided on the downstream side of the heat transfer section passage or the heat transfer section, and an intermittent or continuous projection is formed on the inner circumference of the throttle. A fuel vaporization accelerating device characterized by having a shape protruding from the fuel vaporization device. Means for rotating air by applying air to the fuel spray injected from the liquid fuel injection valve, and colliding the fuel spray with a heat transfer section disposed downstream of the fuel injection valve to supply the fuel spray to an intake pipe At
At least one throttle is provided on the heat transfer section passage or the heat transfer section downstream side, and an intermittent or continuous projection is formed on the throttle inner peripheral portion, and the projection is on the downstream side in the heat transfer section path axial flow direction. A fuel vaporization accelerating device characterized in that the fuel vaporization protruding shape is provided. Means for rotating air by applying air to the fuel spray injected from the liquid fuel injection valve, and colliding the fuel spray with a heat transfer section disposed downstream of the fuel injection valve to supply the fuel spray to an intake pipe At
At least one or more throttles are provided on the heat transfer section passage or the heat transfer section downstream side, and intermittent or continuous projections are formed on the inner circumference of the throttle. A fuel vaporization promoting device having a shape protruding to both downstream sides. 5. The fuel vaporization accelerating device according to claim 2, wherein the projection forms a cylindrical surface parallel to the axial direction of the heat transfer section passage. 6. An internal combustion engine comprising the fuel vaporization accelerating device according to any one of claims 1 to 4.

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