JP2003206833A - Fuel carburetion promoting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fuel carburetion promoting device which performs atomization in a cold start, promote carburetion, reduces deposition of fuel on an inner wall surface of an intake pipe, improves the startability and the fuel consumption of an internal combustion engine for a car, and controls the exhaust emission. <P>SOLUTION: The fuel 24 is uniformly diffused over a heat transfer surface 76 to effectively promote carburetion by forming small grooves 201 of the shape that the fuel 24 is diffused by the surface tension between the heat transfer surface 76 and the fuel 24 on the heat transfer surface 76 in the fuel carburetion promoting device 100 having a fuel injection valve 13 on the upstream side of an intake collecting pipe 11. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply technique for achieving good combustion in an internal combustion engine of an automobile.

[0002]

2. Description of the Related Art In an internal combustion engine, atomization and vaporization of a fuel spray injected by a fuel injection valve (injector) are performed to improve startability, improve fuel efficiency and purify exhaust gas, and particularly to reduce HC in exhaust gas purification. It is effective to reduce the adhesion to the wall surface. Combustion is stabilized by atomizing and vaporizing the fuel and supplying it.

In order to supply atomized and vaporized fuel spray to an internal combustion engine, it is known to provide a fuel injection valve (injector) which is mainly used as an auxiliary when starting the internal combustion engine. USP 5,894,832 discloses a cold start fuel control system including a cold start fuel injector, a heater, and an idle speed control valve (hereinafter referred to as ISC valve).

In this system, the spray injected from the fuel injection valve disposed downstream of the ISC valve of the internal combustion engine and the IS
Mixing is promoted by adding swirl to the intake air that has passed through the C valve, and the mixed gas that has been promoted is collided with a heater disposed downstream of the fuel injection valve to be heated and vaporized, whereby the fuel intake pipe Adhesion on the wall surface is reduced.

[0005]

The above conventional system is
Although the fuel spray is made to collide with a heater disposed downstream of the fuel injection valve to promote vaporization of the spray by the heat generation of the heater, it cannot be said that improvement of the vaporization efficiency of the fuel spray is necessarily sufficient.

An object of the present invention is to improve the vaporization efficiency of fuel spray by a heater.

[0007]

In order to achieve the above object, in the present invention, a liquid film forming means for forming a thin liquid film of fuel injected from a fuel injection valve is provided on the surface of the heat transfer section. A thin film and uniform dispersion of the fuel liquid film supplied to the surface of the heat transfer section are possible, and vaporization efficiency can be improved.

At this time, the heat transfer area can be expanded by making the heat transfer surface uneven. As a result, the heater portion can be downsized, and the throttle body and the intake manifold can be easily built in and can be easily mounted on the engine. In addition to the above means,
By causing air to act on the fuel spray injected from the fuel injection valve, atomization of the fuel spray or transfer of the fuel in the downstream direction can be improved, and the fuel spray can be made to uniformly collide with the surface of the heat transfer section. It becomes possible to further reduce the thickness of the fuel liquid film and uniformly disperse it.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS.

In FIG. 1, the internal combustion engine 1 is a known ignition type internal combustion engine that uses gasoline as fuel, but only one cylinder is shown in the drawing.

The internal combustion engine 1 has an ignition plug 3 arranged in a combustion chamber 2, an intake valve 4 for taking in air and mixed air, and an exhaust valve 5 for exhausting after combustion. The internal combustion engine 1 is
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 are provided on the side of the combustion chamber 2 to detect the operating state.

The intake system for intake air into the combustion chamber 2 has an intake air 26 that passes through an air cleaner (not shown) and is taken in.
And an electronically controlled throttle valve 10 for electrically controlling the amount of intake air that is mounted on a rotary shaft that rotates in conjunction with the driver's operation of the accelerator pedal or the operating state of the internal combustion engine and that opens and closes. And a throttle positioning sensor 130, the intake manifold 11,
An intake manifold 39 that branches from the intake collecting pipe 11 to each cylinder of the internal combustion engine 1, and an intake port 14 including an intake valve 4.
And so on.

The flow rate of the intake air 26 and the opening degree information of the valve portion 131 of the throttle valve 10 measured by the air flow sensor 8 and the throttle positioning sensor 130 are input to the controller 35 to detect the operating state of the internal combustion engine 1 and various information. Used for control.

The fuel injection device is composed of a first fuel injection valve 12 and a second fuel injection valve 13. The first 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 collective intake pipe 11.

The second fuel injection valve 13 is attached to the fuel vaporization promoting device 100, and the electronically controlled throttle valve 1 is provided.
It is configured such that it is introduced into the intake collecting pipe 11 through a branch passage 15 that is open downstream.

The fuel system is a fuel tank 1 for storing fuel 24.
6, a fuel pump 17 for pumping the fuel 24 from the fuel tank 16, a fuel filter 18, and a pressure regulator 1 for adjusting the pressure of the pumped fuel 24 to a predetermined pressure.
9, a first fuel injection valve 12 for injecting fuel into the intake port 14 of each cylinder (# 1, # 2, ...) And a second fuel injection valve 1 for supplying fuel downstream of the throttle valve portion 131.
3, which are connected by a fuel pipe 38.

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, and a three-way catalytic converter 21 for purifying the exhaust. And a muffler (not shown). 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 emits NOx, C exhausted from the internal combustion engine 1 operated near the stoichiometric air-fuel ratio.
O and HC are simultaneously purified with a high purification rate.

The fuel vaporization promoting device 100 is connected to an open branch passage 15 downstream of the electronically controlled throttle valve 10, and an electronic device is provided to introduce the air measured by the air flow sensor 8 into the fuel vaporization promoting device 100. To bypass the control throttle valve 10 from upstream to downstream,
Bypass passages 22 and 23 branched from the intake pipe 9 are formed. The bypass passage 22 includes the second fuel injection valve 1
3 is an air passage for carrying the fuel 24 injected from No. 3, and the amount of air flowing through the bypass passage 22 is adjusted by a flow rate adjusting 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 sprayed from the second fuel injection valve.

In the above structure, in the combustion chamber 2, the fuel 24 injected by the fuel injection valves 12 and 13 and the intake air 2
The mixture of 6 is inhaled. The sucked air-fuel mixture is compressed, ignited by the spark plug 3 and burned. Exhaust gas 42 discharged from the internal combustion engine 1 is discharged into the atmosphere from the exhaust system.

The structure of the fuel vaporization promoting device 100 will be described with reference to FIGS. FIG. 2A is an external perspective view of the fuel vaporizer 100. The fuel vaporizer 100 is composed of a body 102 and a heater body 101,
The body 102 is mainly provided with the second fuel injection valve 13, the carrier air introduction pipe 30, and the atomized air introduction pipe 31. The bypass passage 22 communicates with the carrier air introduction pipe 30, and the carrier air 22a flows in.
The bypass passage 23 communicates with the atomized air introduction pipe 31, and the atomized air 23a flows in. Then, the fuel injection valve 13 is connected to the fuel pump 17 from the fuel tank 16.
And the fuel 24 is supplied through the fuel pipe 30.

Further, the heater body 101 has a built-in heater, which will be described later, and is provided with positive and negative electrode terminals 28 and 29 for energizing the heater. The fuel 24 vaporized in the heater body 101 flows out of the fuel vaporization promoting device 100 as vaporized fuel 33 indicated by a white arrow.

FIG. 2 is a view taken in the directions of arrows A and B in FIG.
Shown in (b) and (c).

FIG. 3 is a sectional view taken along line CC in FIG. 2 (b). FIG. 4 shows a sectional view taken along the line DD in FIG.

A sub-passage 75 formed inside the heater body 101 having a deflection angle α ° attached to the branch passage 15 opened downstream of the electronically controlled throttle valve 10, and a plate-shaped heater disposed around the sub-passage 75. 10. This heater (ceramic heater) has upper and lower flat portions serving as electrodes, and heat is generated by applying a current to the upper and lower electrodes. Further, the heater, which is a heating element, has a PTC (Positive Tem) that can maintain a constant temperature when the temperature exceeds a predetermined value, the electric resistance increases sharply and the current decreases.
perature Coefficient Thermistor) heater is used.

The PTC heater 77 is fixed so as to come into contact with the auxiliary passage 75 that serves as a minus electrode and the plus electrode plate 79. The plus electrode plate 79 is held by the elastic member 78 and is connected to the plus electrode terminal 28 arranged outside the heater body 101 via the electrode portion 80. The conductive sub-passage 75 is press-fitted and fixed to the electrode portion 82, and is connected to the minus electrode terminal 29 outside the heater body 101. The electrode portions 82 and 80 are insulated from each other by the insulating member 81 and the elastic member 78, and when the electrode portions 82 and 80 are energized, the PTC heater 77 generates heat to heat the sub passage 75.

The sub passage 75 includes an O-ring 74 and a gasket 7.
2 is sealed from the internal passage. Gasket 7
2 is compression-sealed so as to be sandwiched between the heater body 101 and the body 102. The body 102 has a second fuel injection valve 13 arranged coaxially with the heater body 101.
And the fuel injection valve 13 has a case 70 having an air introduction hole.
Air atomizer 55 and O ring 84, which are press-fitted and fixed in
The O-ring 72 is positioned so as to seal the internal passage in the body 102, and is fixed to the body 102 by the fuel pipe 34 and the fuel pipe member 83. The fuel passage is sealed by disposing an O-ring 73 between the fuel pipe 34 and the fuel injection valve 13.

In the present embodiment, there is a pressure difference between the upstream side and the downstream side of the valve portion 131 of the electronically controlled throttle valve 10. Therefore, when the valve portion 131 of the electronically controlled throttle valve 10 is closed, the electronically controlled throttle valve is closed. Air flows through the air passages 22 and 23 that bypass the valve 10. Further, the fuel vaporization promoting device 100 is configured in this bypass passage, and the atomized air 2 is added to the fuel spray 85 injected from the fuel injection valve 13 of the fuel vaporization promoting device 100.
3a is swirled and collided by the air atomizer 55, and the fuel 24 is atomized and the spray angle is widened and injected into the mixing chamber 56, and the injected fuel 24 and the carrier air 22a bypassed from the carrier air introduction pipe 30 by the bypass passage 22 are discharged. It is designed to swirl and collide with the swirling nozzle 51, swirl and adhere to the heat transfer surface 76 of the inner surface of the heated sub passage 75, and vaporize the fuel spray 85 when passing over the heat transfer surface 76. .

Here, fine grooves are formed on the heat transfer surface 76 so as to be substantially orthogonal to the axial direction of the sub passage 75.
The fuel spray 85 injected from the fuel injection valve 13 has the atomization air 23a promotes atomization, and then the swirling nozzle 5
A swirl is provided by the carrier air 22a via 1.
As a result, the spray 85 is promoted to be atomized and becomes a wide-angle spray. Then, the heat transfer surface 7 on the inner wall of the sub passage 75
6 is supplied to the groove 201 formed. The fuel spray 85 supplied to the groove 201 diffuses into the heat transfer surface 76 due to the shape of the groove 201 and the surface tension of the fuel. Due to the groove 201, the fuel spray 85 can be further uniformly dispersed on the heat transfer surface. Further, the heat transfer area is expanded by forming the groove 201. Therefore, the fuel liquid film formed on the heat transfer surface can be thinned, and vaporization can be efficiently promoted. Therefore, the vaporization efficiency of the fuel due to the heat generation of the heater can be improved, and the power consumption can be reduced.

Incidentally, as the groove shape of this kind, the auxiliary passage 75
The groove inclined from the axial flow direction may be a spiral groove formed continuously along the air flow direction passing through the heat transfer section. When the grooves are formed as a plurality of grooves that are independent in the axial flow direction, it is expected that the fuel spray is retained in each groove and vaporized. Further, in the case of the spiral groove, it can be expanded to a wider range in the axial flow direction.

The cross-sectional shape of the mixing chamber will be described with reference to FIG.
In the structure in which a is introduced from one side of the pressure regulation chamber 50, the blade cross-sectional shape has a wide inlet-side sectional area, a narrow outlet-side sectional area, and a plurality of equal intervals circumferentially arranged at positions displaced from the axial center. The swirling nozzle 51 is opened in the flow direction of the bypass carrier air 22a, and the carrier air flow 52 passing through the swirl nozzle 51 has a constant flow velocity so that the pressure regulating chamber 5
The swirl shape is such that the cross-sectional area of 0 gradually narrows as it goes downstream. The swirl has a structure in which the outer diameter of the pressure regulation chamber 50 is constant and the height of the depth is gradually reduced, so that the swirl structure can be adopted in a limited space. As a result, the carrier air 52 flowing into the mixing chamber 56 becomes uniform, and when the fuel 19 injected from the fuel injection valve 25 adheres to the inner surface of the sub passage 13, the liquid film becomes uniform and vaporization is effectively promoted. It becomes possible to do.

Further, by making the introduction passage from the sub passage 75 into the main passage a deflected shape, the velocity component in the straight traveling direction decreases, so that the swirling force generated in the swirling nozzle 51 increases, so that the heat transfer surface is increased. It is possible to increase the number of turns of the fuel liquid film and increase the residence time of the fuel adhering to the sub passage 75.

FIG. 5 is an enlarged sectional view of a portion E in FIG. An inner cylinder 200 is arranged on the inner peripheral surface side of the heater body 101 with a predetermined air layer in between. An elastic member 78 made of an elastic material is disposed in surface contact with the inner peripheral surface of the inner cylinder 200. A brass electrode plate 79 is arranged in surface contact with the inner surface of the elastic member 78. 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 member forming the heat transfer surface 76. With these structures, the positive electrode plate 79 is in surface contact with the PTC heater 77 and the heat transfer surface 76. Here, the heat transfer surface 76 is also a negative electrode portion. Therefore, the above-mentioned electrode terminals 28, 2
When a current is applied to 9, the current is applied from the positive electrode plate 79 to the heat transfer surface 76 via the PTC heater 77. As a result, the PTC heater 77 generates heat and the heat transfer surface 76 can be heated.

Here, the groove 201 formed in the heat transfer surface 76.
As a result, the heat transfer area on the inner circumference of the sub passage 75 can be increased, and the fuel liquid film injected onto the heat transfer surface can be uniformly dispersed. Details will be described later.

FIG. 6 shows a groove shape formed on the heat transfer surface 76 of the fuel vaporization promoting apparatus 100, and is an enlarged view of an F portion in FIG. The shape of the groove 201 is a trapezoidal shape having a groove opening length b, a groove bottom c, and a groove angle θ. Further, the respective grooves formed on the heat transfer surface 76 are continuous at the groove top portion t having a length t. Therefore, the groove pitch is (b + t). Further, the fuel spray 85 supplied to the heat transfer surface 76 is stored in the groove 201 as the liquid fuel 24.

In a certain groove, two points where the inclined portion of the groove 201 and the gas-liquid interface of fuel and air contact each other are defined as gas-liquid interface width d
And Further, it is assumed that gasoline, which is a fuel, has good wettability, and if the contact angle θ ₀ is zero, the gas-liquid interface curvature radius a in the groove 201 can be expressed as in (Equation 1).

A = b / (2 · cos (θ / 2)) (Equation 1) Here, the gas-liquid interface curvature radius a is a virtual curve, unlike the actual gas-liquid interface curvature radius. Further, the contact angle θ ₀ being zero is the same value as the tangential direction of the inclined portion of the groove 201, and when the inclined portion is a curved surface, the contact angle θ ₀ is the same value as the tangential direction of the curved portion at a predetermined position. Further, it is preferable that the groove opening length b is equal to the gas-liquid interface width d.
It is desirable that the groove opening length b be equal to the groove opening length b and the gas-liquid interface width d.

This is because the heat transfer surface 76 other than the groove top portion t is not directly exposed to the air layer without the fuel liquid film, so that the vaporization of the fuel is promoted.

Here, the cross-sectional area of the fuel 24 stored in one groove 201 is S, and the contact length between the fuel 24 and the groove 201 where the inclined portion of the groove 201 contacts the gas-liquid interface curvature radius a is L.
If s, the fuel 24 stored in the groove 201 balances the surface tension acting between the contact length Ls of the fuel and the wall surface of the groove and the weight of the fuel that has risen in the groove, and therefore, the force balance equation is obtained. (2), the liquid rising height h due to the surface tension is determined by the contact length Ls and the liquid cross-sectional area S. Here, σ is the surface tension of the fuel, ρ is the density, and g is the gravitational acceleration.

From h = (σ / (ρ · g)) · (Ls / S) (Equation 2) (Equation 2), the fuel increase height h can be increased to a predetermined height.

Therefore, the fuel 24 deposited on the heat transfer surface 76
With the relationship between the contact length Ls of the groove 201 and the liquid cross-sectional area S, it becomes possible to uniformly disperse the liquid film in the inner peripheral direction of the sub passage 75. Further, since the carrier air 22a and the atomized air 23a passing through the sub passage 75 have a flow component in the axial direction of the sub passage 75, the fuel liquid film is efficiently supplied also to the downstream side of the heat transfer surface 76. Vaporization is promoted. Furthermore, the groove 20
Since the inclined portion in 1 and the liquid film for fuel 24 form a liquid cross section with a gas-liquid interface curvature radius a, the fuel liquid film can be locally thinned at the groove portion, and the groove 201 forms the heat transfer surface 76 portion. The heat transfer area can be expanded and the fuel vaporization can be further promoted as compared with the case where is smooth. Further, the pressure difference between the upstream and downstream sides of the throttle valve unit 131 may vary depending on the operating condition of the internal combustion engine 1. Therefore, the intake air amounts of the carrier air 22a and the atomized air 23a also change. Therefore, in order to always uniformly supply the fuel spray 85 to the heat transfer surface 76, the groove 201 may have a contact length Ls and a liquid cross-sectional area S that are the liquid rising height h reaching the inner diameter of the auxiliary passage 75 or more. preferable.

Here, the groove 201 cross-sectional shape shown in FIG. 6 is a trapezoidal groove 201 cross-sectional shape connected by a straight line, but as shown in FIG. But good. In this embodiment, the trapezoidal groove 2 is used.
Similar to the 01 cross-sectional shape, it has the effect of dispersing the fuel liquid film along the inner wall surface of the heat transfer surface 76.

FIG. 7 shows the contact length L between the groove 201 and the fuel 24.
The results obtained by organizing the relationship between s and h · S, which is the product of the liquid rising height h and the liquid cross-sectional area S, are shown. It can be seen that Ls and h · S are in a proportional relationship, and h · S increases as the contact length Ls increases. For example, assuming that the groove cross-sectional shape is a predetermined shape, and assuming that the radius of curvature of the gas-liquid interface in the groove is a, h · s is 1.4 when the contact length Ls is 0.56 mm.
It is about 1 mm ³ . The fuel rising height h at this time is obtained from the previously assumed liquid cross-sectional area S. By making φd which is the inner diameter of the auxiliary passage 75 smaller than this rising height h,
The fuel 24 adhering to the heat transfer surface 76 can be uniformly supplied on the circumference. That is, φd <(σ / (ρ ·
g)) · (Ls / S). here,
φd is the inner diameter of the cylindrical heat transfer section, σ is the surface tension of the fuel, g is the gravitational acceleration, Ls is the contact length at which the heat transfer surface contacts the fuel, and s
Is the cross-sectional area of the fuel stored in the groove.

FIG. 8 shows the relationship of the fuel rising height h when the groove width b is predetermined. For example, the groove opening length b is 0.3 m
m, the groove bottom length c is 0.034 mm and the groove angle is 60 °, the fuel rising height h is about 71 mm. Here, the groove opening length b and the gas-liquid interface width d are
The same. Therefore, φd, which is the inner diameter of the auxiliary passage 75, is set to 7
It is preferably 1 mm or less. As a result, the liquid film can be uniformly dispersed in the circumferential direction of the heat transfer surface 76 in the sub passage 75, and vaporization of fuel can be promoted.

By forming the heat transfer surface 76 in consideration of the groove shape, the amount of fuel vaporization can be increased, and as a result, the number of PTC heaters 77 can be reduced, and a power saving type small fuel vaporization promoting device 100 can be realized. it can.

FIG. 9 shows the heat transfer surface 7 of the fuel vaporization promoting device 100.
6 shows the relationship between the amount of vaporized fuel when a groove is provided (with a groove) and when it is not provided (without a groove). By optimizing and forming the groove by the effect described above, it is possible to increase the vaporized fuel amount by about 20 to 30%.

Next, a second embodiment of the present invention will be described with reference to FIG. The difference from the first embodiment is the way of forming the groove 202 formed in the heat transfer surface 76.
The rest of the configuration is similar to that of the first embodiment, so its explanation is omitted. In the present embodiment, the groove 202 formed on the heat transfer surface 76 has a groove forming direction 87 which is substantially the same as the swirling flow 86 direction of the intake air. The fuel spray 85 passing through the sub passage 75 is swirl-supplied and adheres to the heat transfer surface 76 by the intake air flow of the carrier air 22a and the atomized air 23a. The attached fuel 24 flows as a swirling flow 86 along the swirling flow of the intake air. Therefore, the groove 2
Since the forming direction 87 of 02 and the direction of the swirling flow 86 coincide with each other, the contact length Ls formed by the fuel 24 stored in the groove 202 and the transmission surface 76 in the groove 202 becomes maximum. That is, as shown in FIG. 10B, since the swirling flow 86 direction and the groove forming direction 87 are substantially the same direction, the fuel 24
The contact length Ls between the groove 202 and the groove 202 is sufficiently obtained. However, as shown in FIG. 10C, when the swirling flow 86 direction and the groove forming direction 87 are different, the contact length Ls between the fuel 24 and the groove 202 is shortened and the heat transfer surface is not in contact with the fuel. Because of the large number, the fuel vaporization efficiency is reduced.
Therefore, it is preferable that the swirling flow 86 direction and the groove forming direction 87 are substantially the same direction, and the heat from the heat transfer surface 76 can be efficiently supplied to the fuel 24, so that the fuel vaporization efficiency can be further improved. The other actions and effects are the same as those of the first embodiment, so the description thereof will be omitted.

Next, a third embodiment of the present invention will be described with reference to FIG. The difference from the first embodiment is the way of forming the groove 203 formed in the heat transfer surface 76.
The rest of the configuration is similar to that of the first embodiment, so its explanation is omitted. In this embodiment, the groove 203 formed on the heat transfer surface 76 is formed so that the axial direction of the sub passage 75 and the groove forming direction 88 are the same. The fuel spray 85 passing through the sub passage 75 is formed by the carrier air 22a and the atomized air 23a.
Is swirlingly supplied to and adheres to the heat transfer surface 76. Here, the fuel spray 85 adheres to the heat transfer surface 76 relatively upstream of the heat transfer surface 76. As a countermeasure, the groove 20
By forming 3 in the same direction as the axial direction of the auxiliary passage 75 and the groove forming direction 88, the fuel flows into the downstream in the axial direction due to the surface tension of the fuel 24 adhering to the heat transfer surface 76, and becomes uniform early. A fuel liquid film is formed on the heat transfer surface 76. Therefore, the fuel vaporization efficiency can be improved. The other actions and effects are the same as those of the first embodiment, so the description thereof will be omitted.

Next, a fourth embodiment of the present invention will be described with reference to FIG. The difference from the configuration of the first embodiment is the way of forming the groove 204 formed in the heat transfer surface 76.
The rest of the configuration is similar to that of the first embodiment, so its explanation is omitted. In the present embodiment, the grooves 204 having a grid-like uneven shape are formed on the heat transfer surface 76. This is a shape in which a shape like a knurled eyelet has fine irregularities. This makes it possible to secure a groove-shaped portion that is relatively along the intake air flow 86 flowing into the heat transfer surface 76, and further allows the fuel accumulated in the groove 204 to flow in the circumferential direction and the axial flow direction of the heat transfer surface 76. At the same time, it can be dispersed by the surface tension, so that the fuel vaporization efficiency can be improved. The other actions and effects are the same as those of the first embodiment, so the description thereof will be omitted.

In the first to fourth embodiments, the heat transfer surface 7
Although the groove shape formed in No. 6 has been described, the groove shape is not limited to this, and a fine uneven shape is formed in the heat transfer surface 76 that actively diffuses the liquid film and promotes fuel vaporization. If it is a heat side, the same effect as this embodiment can be obtained. Further, regarding the uneven shape formed on the heat transfer surface 76,
In this embodiment, the heat transfer area of the groove per unit area has been described as a concavo-convex shape having a uniform heat transfer surface.
Is injected from the upstream side of the heat transfer surface 76, and
Tends to adhere to the upstream side, and the fuel liquid film also tends to thicken. Further, on the downstream side, the fuel liquid film on the heat transfer surface 76 tends to be thin. Therefore, in order to efficiently transfer the amount of heat supplied from the heater to the fuel liquid film via the heat transfer surface and promote the vaporization efficiency, the heat transfer area of the heat transfer surface 76 in the thick portion of the fuel liquid film is large. However, it is preferable to reduce the heat transfer area of the thin portion of the fuel liquid film. Therefore, in the heat transfer surface 76 disposed in the sub passage 75, a concavo-convex shape that continuously or stepwise expands the heat transfer area of the heat transfer surface 76 on the upstream side compared to the downstream side is formed. Is preferred. As a result, heat transfer between the heat transfer surface and the fuel liquid film formed on the heat transfer surface is promoted, so that an effect of reducing power consumption can be obtained.

Further, an embodiment of the attached state of the present invention will be described with reference to FIG. FIG. 13 shows an example of attachment to the electronically controlled throttle valve 10, which has a structure in which the fuel vaporization promoting device 100 and the electronically controlled throttle valve 10 are sealed with a gasket 133 and fastened with a plurality of screws 132. By co-fastening the negative electrode of the heater with the screw 132, the cable of the negative electrode can be eliminated.

By using the internal combustion engine equipped with the fuel vaporization promoting device described above, H emitted from the internal combustion engine
It becomes possible to reduce C. This will be described below with reference to FIG. FIG. 14A is a diagram showing the relationship between the particle size of the fuel spray and the limit of the ignition timing that can be delayed (retarded) while maintaining combustion stability. The particle size of the fuel spray obtained in this embodiment is completely vaporized and the internal combustion engine 1
Since it is supplied to the combustion chamber 2 of No. 1, it is possible to retard the ignition timing largely until the expansion stroke is started. When ignition is performed in the expansion stroke, the rate of expansion of the combustion gas in the combustion chamber decreases, so the amount of heat consumed by the combustion gas due to the expansion work decreases, and the combustion gas while maintaining a high temperature can be discharged to the exhaust pipe. . That is, as shown in FIG. 14 (b), the catalyst 21 can be rapidly warmed up by retarding the ignition timing and discharging the high-temperature combustion gas. It takes less time to reach the activation temperature. That is, as shown in FIG. 14C, the purifying action of the catalyst 21 is started early, so that the amount of HC discharged after the start of the internal combustion engine 1 can be significantly reduced. By the early warm-up of the catalyst (three-way catalytic converter) 24, not only HC but NOx,
It is also possible to reduce CO.

In the fuel vaporization promoting apparatus 100 described above, the means for forming a thin liquid film by dispersing the fuel liquid film on the heat transfer surface 76 in the sub passage 75 has been described.
As means for extending the fuel liquid film, in addition to the means using intake air, the means using surface tension acting on the fuel and the grooves by forming fine grooves on the heat transfer surface 76, and the means for superheating on the heat transfer surface. The same effect as in the present embodiment can be obtained by applying the hydrophilic treatment.

According to the above-described embodiment of the present invention, the surface tension between the heat transfer surface and the surface in contact with the fuel spray causes
By forming a concavo-convex shape on the heat transfer surface so that the fuel spray diffuses, or by applying a superhydrophilic treatment to the heat transfer surface, a thin film of the fuel liquid film supplied to the heat transfer surface and uniform dispersion are possible. Becomes In addition, the uneven shape of the heat transfer surface allows the heat transfer area to be expanded and the fuel vaporization efficiency to be improved. As a result, the number of heaters can be reduced, power consumption can be reduced, and the size of the heater section can be reduced. The built-in body and intake manifold and the ease of mounting on the engine become easy.

Further, by merging the injected fuel with the first air flow (assist air) at the outlet of the fuel injection valve, atomization of the fuel spray is enhanced and the fuel spray is conveyed in the downstream direction. . Further downstream from the position where the first air flow is merged, it is configured such that the flow velocity of the openings arranged on the circumference which is the outer circumference of the fuel spray carried by the first air flow is constant. The second swirling air flow is uniformly combined from the scroll-shaped air passage, and the spray is uniformly collided with the surface of the heat transfer section. Join the fuel spray 2
A single air flow allows for even more thin film and uniform distribution of the fuel liquid film.

By improving the vaporization efficiency of the fuel spray by the heater, the consumed electric energy can be reduced and the reliability and durability of the heater can be improved. Further, atomization of spray and promotion of vaporization can be achieved at the time of low temperature start, and the adhesion of fuel to the inner wall surface of the intake pipe can be reduced to improve the startability of the internal combustion engine for automobiles, improve fuel efficiency, and reduce exhaust gas purification.

[0057]

According to the present invention, since the vaporization of the fuel spray can be promoted and the adhesion of the fuel spray to the wall surface can be reduced, not only the startability and fuel efficiency of the internal combustion engine can be improved but also the exhaust gas purification can be improved.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of an internal combustion engine equipped with a fuel vaporization promoting device according to the present invention.

FIG. 2 is a perspective view of the fuel vaporization promoting device shown in FIG. 1 according to the present invention.

FIG. 3 is a cross-sectional view of the fuel vaporization promoting device CC shown in FIG. 2 (b) according to the present invention.

FIG. 4 is a sectional view of the fuel vaporization promoting device DD shown in FIG. 2 (c) according to the present invention.

5 is an enlarged cross-sectional view of a heat transfer surface groove portion of the fuel vaporization promoting device shown in FIG. 3 according to the present invention.

6 is an enlarged cross-sectional view of a heat transfer surface groove portion of the fuel vaporization promoting device shown in FIG. 5 according to the present invention.

FIG. 7 is a diagram showing the relationship between the contact length between the fuel and the groove, the rise in fuel liquid, and the liquid cross-sectional area.

FIG. 8 is a diagram showing a relationship between a groove width and a fuel rising height when a predetermined groove cross-sectional shape is formed.

FIG. 9 is a diagram for explaining the effect of the groove shape of the heat transfer surface.

FIG. 10 is a sectional view of a fuel vaporization promoting device according to a second embodiment of the present invention.

FIG. 11 is a sectional view of a fuel vaporization promoting device according to a third embodiment of the present invention.

FIG. 12 is a sectional view of a fuel vaporization promoting device according to a fourth embodiment of the present invention.

FIG. 13 is an embodiment of a method of mounting the fuel vaporization promoting device.

FIG. 14 is a diagram illustrating the relationship between fuel vaporization, catalyst temperature, and HC emission amount.

15 is a diagram showing an example in which the groove cross-sectional shape shown in FIG. 6 is formed by connecting the curved lines.

[Explanation of symbols]

1 ... Internal combustion engine, 2 ... Combustion chamber, 3 ... Spark plug, 4 ... Intake valve,
5 ... Exhaust valve, 8 ... Air flow sensor, 9 ... Intake pipe, 10 ... Electronically controlled throttle valve, 11 ... Intake manifold, 12 ... First fuel injection valve, 13 ... Second fuel injection valve, 21 ... Three-way Catalytic converter, 22 ... Bypass passage, 22a ... Carrier air, 23a ... Atomization air, 25 ... Flow control valve, 26 ... Intake air, 33 ... Vaporized fuel, 30 ... Fuel vaporization promoting device, 75 ... Sub passage, 76 ... Transmission Hot side,
77 ... PTC heater, 201 ... groove.

Continued front page    (72) Inventor Yuzo Kadoko             502 Kintatemachi, Tsuchiura City, Ibaraki Japan             Tate Seisakusho Mechanical Research Center (72) Inventor Hiroaki Saeki             2477 Takaba, Hitachinaka City, Ibaraki Prefecture Stock Association             Inside Hitachi Car Engineering (72) Inventor Kenji Watanabe             Hitachinaka City, Ibaraki Prefecture 2520 Takaba             Ceremony Company Hitachi Ltd. Automotive equipment group (72) Inventor Takanobu Ichihara             Hitachinaka City, Ibaraki Prefecture 2520 Takaba             Ceremony Company Hitachi Ltd. Automotive equipment group (72) Inventor Masami Nagano             Hitachinaka City, Ibaraki Prefecture 2520 Takaba             Ceremony Company Hitachi Ltd. Automotive equipment group F term (reference) 3G066 AA01 AB02 AD11 BA17 BA26                       CC46 CD22

Claims (9)

[Claims] 1. A fuel vaporization promoting device for vaporizing fuel by colliding a fuel spray injected from a fuel injection valve with a heat transfer portion provided downstream of the fuel injection valve, wherein the fuel vaporization promoting device is the transmission device. A fuel vaporization promoting device comprising liquid film forming means for forming a thin liquid film of fuel injected from a fuel injection valve on a surface of a heat section. 2. The fuel vaporization promoting device according to claim 1, wherein the liquid film forming means has a surface shape on the surface of the heat transfer portion that widens a contact area with the fuel, and the fuel and the heat transfer portion. A fuel vaporization promoting device characterized in that fuel is diffused by surface tension with the surface. 3. A fuel vaporization promoting device for vaporizing fuel by colliding a fuel spray injected from a fuel injection valve with a heat transfer portion provided downstream of the fuel injection valve, wherein the fuel vaporization promoting device comprises: A fuel vaporization promoting device, characterized in that unevenness is formed on the surface of the heating portion. 4. The fuel vaporization promoting device according to claim 3, wherein the irregularities are formed by grooves formed so as to be substantially orthogonal to the axial direction of the heat transfer section. 5. The fuel vaporization promoting apparatus according to claim 3, wherein the irregularities are formed by grooves formed along the axial direction of the heat transfer section. 6. The fuel vaporization promoting device according to claim 3, wherein the irregularities are formed by grooves formed on the surface of the cylindrical heat transfer section, d is the inner diameter of the cylindrical heat transfer section, and σ is the surface tension of the fuel. , Ρ is the density, g is the gravitational acceleration, Ls is the contact length between the heat transfer surface and the fuel, and s is the fuel cross-sectional area stored in the groove,
Between d, σ, ρ, g, Ls and S, d <(σ / (ρ ·
g)) · (Ls / S), the fuel vaporization promoting device. 7. The fuel vaporization promoting device according to claim 1 or 3, wherein the surface of the heat transfer portion is subjected to a superhydrophilic treatment. 8. The fuel vaporization promoting device according to claim 1, further comprising an intake pipe provided with a throttle valve, and a swirling air supply nozzle for causing swirling air to act on the fuel spray injected from the fuel injection valve. The fuel vaporization promoting device, wherein the heat transfer portion is provided on the downstream side of the swirl nozzle, and the downstream passage of the heat transfer portion is connected to the downstream passage of the intake pipe. 9. The fuel vaporization promoting device according to claim 8, wherein air is made to act on the fuel spray injected from the fuel injection valve to the intake pipe downstream of the throttle valve upstream of the swirling air supply nozzle, and fine particles are produced. An apparatus for promoting fuel vaporization, comprising an air atomizer for promoting vaporization.