JPH05256231A - Heating system fuel feed device - Google Patents

Abstract

PURPOSE:To introduce a structure which can facilitate the atomization of fuel at the time of engine start and its cold state into a heating system fuel feed- device to which heated air is applied. CONSTITUTION:Intake air fed to an engine 42 is partially led from an inlet provided on the downstream side of a flowmeter 27 in an intake pipe 33 and the upstream side of a throttle valve 4 to an air passage 2. The above air is heated by an electric heater 3 provided in the air passage 2, and strikes against fuel jetting from a fuel injection valve 1 for facilitating the atomization of the fuel. Engine cooling water temperature TW detected by a water temperature sensor 46 is sent to a microcomputer 44, and heating made by the electric heater 3 through a heating circuit 43 and the opening and closing of an idle speed control valve 45 are carried out by a command issued from the microcomputer 44 on a signal for the temperature TW. Thus the atomization of fuel at the time of engine start and its cold state can be controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel supply system provided with a fuel injection valve for supplying fuel to an engine in an internal combustion engine, and more particularly to a heating type fuel supply system which applies heated air to atomize the fuel. ..

[0002]

2. Description of the Related Art Conventionally, as a method of promoting atomization of fuel in a fuel supply device, a part of an intake air flow is heated by utilizing heat of exhaust gas, and this is used as fuel from a fuel injection valve. By mixing them, the atomization of the fuel was promoted.
There are the following known examples of this atomization promoting device.

1. Fuel atomization promoting device for internal combustion engine (Japanese Patent Laid-Open No. 56-6064) In this prior art, a part of intake air supplied to an engine combustion chamber is taken out from an intake system and is mounted around an exhaust pipe. Is heated by the heat quantity of the exhaust gas. This heated air is made to collide with the side surface of the fuel injection flow from a discharge nozzle provided in the immediate vicinity of the fuel injection valve. As a result, during normal operation after engine warm-up, the fuel efficiency of the fuel injection device, which was said to be inferior to that of the carburetor system, is prevented while preventing a decrease in intake efficiency and a decrease in engine output that occur when heating the entire intake air. It is intended to promote atomization.

2. Secondary intake device for fuel injection engine
7-59052) In this conventional technique, part of the supply air is guided to the auxiliary intake pipe and part of the exhaust gas is also guided to the auxiliary exhaust pipe as in the above-mentioned known example, and the auxiliary intake pipe and the auxiliary exhaust pipe are combined. Assist air heated by the counterflow heat exchanger is ejected to the tip of the fuel injection valve. As a result, the atomization of the fuel injected from the fuel injection valve is promoted, the fuel efficiency is improved, and the HC emission is reduced, both in the cold state of the engine and after the warm-up, as in the case of the first known example.

[0005]

The above-mentioned known techniques have the following problems, respectively.

In the first known example, when the engine is cold such as when the engine is started, the temperature of the cooling water of the engine is low and the idle speed control valve is operating. Does not flow to the heat exchanger.
In addition, since exhaust gas is used as a heat source, it cannot be applied when the engine is started, and the amount of heat of the exhaust gas is not sufficient after the engine is cold when the engine is cold, and the effect of heating is low.

In the known example of 2, the intake air to the heat exchanger is secured by closing the two-way valve of the auxiliary intake pipe when the engine is cold, but the exhaust gas is used as the heat source as in the known example of 1. Therefore, it cannot be applied when the engine is started, and when the engine is cold, the heat quantity of the exhaust gas is not sufficient and the effect of heating is low. An object of the present invention is to obtain a structure capable of promoting atomization of fuel at the time of engine start and engine cold in a heating type fuel supply device which atomizes fuel by applying heated air.

[0008]

In order to achieve the above object, the present invention provides a heating means for heating a part of intake air, and applies the heated air to fuel ejected from a fuel injection valve, In a heating type fuel supply device for atomizing fuel, an electric heater provided as the heating means, an air supply means for passing a part of the intake air through the electric heater, an engine cooling water temperature are detected, and the water temperature is And a control means for operating the electric heater and the air supply means when the temperature is equal to or lower than a predetermined temperature.

The electric heater is preferably composed of a mesh-like thin plate.

Further, preferably, the electric heater is integrated with a gallery which constitutes an air passage for supplying the air to a plurality of cylinders, or is provided at an inlet portion where a part of the intake air enters the fuel injection valve. Or an air passage for guiding the air heated by the electric heater to the fuel injection valve and an intake pipe integrally formed, or provided in an air passage for guiding a part of the intake air in the fuel injection valve. May be.

The control means preferably starts heating by the electric heater before starting cranking of the engine.

Further, the control means preferably stops the heating by the electric heater when the cooling water temperature of the engine reaches a predetermined temperature.

The air supply means is preferably means for closing the idle speed control valve,
The control means operates the idle speed control valve during cranking of the engine and closes it.

Further, in the heating type fuel supply device, preferably, the air supply means is an air pump provided in an air passage for guiding a part of the intake air, and the control means operates the pump when cranking the engine. To operate.

The electric heater is preferably a means for directly heating an air passage for guiding a part of the intake air.

[0016]

In the present invention constructed as above, the electric heater provided as the heating means, the air supplying means for passing a part of the intake air through the electric heater, the cooling water temperature of the engine are detected, and the water temperature is detected. Has a control means for operating the electric heater and the air supply means when the temperature is equal to or lower than a predetermined temperature, the supply air can be heated to promote atomization of the fuel even when the engine is cold when the cooling water temperature is low. it can.

Further, the electric heater may be formed of a mesh-like thin plate, or the electric heater may be integrated with a gallery forming an air passage for supplying the air to a plurality of cylinders, or the fuel injection valve may be provided with the suction port. It is provided at an inlet part where a part of the air enters, or it is formed integrally with an air passage for guiding the air heated by the electric heater to the fuel injection valve and in an intake pipe, or the suction in the fuel injection valve. By providing the air passage in which a part of the air is guided, the installation space can be minimized and the air can be efficiently heated.

Further, the control means starts the heating by the electric heater before the cranking of the engine, or stops the heating by the electric heater when the cooling water temperature of the engine reaches a predetermined temperature. Alternatively, the air supply means is means for closing the idle speed control valve, and the control means operates the idle speed control valve to close it during cranking of the engine, or the air supply means causes one of the intake air An air pump provided in an air passage that guides the engine, wherein the control means operates the air pump during cranking of the engine to heat the supply air even when the engine is started to promote atomization of fuel. You can

Further, the electric heater is a means for directly heating the air passage for guiding a part of the intake air,
The installation space can be minimized and the air can be efficiently heated.

[0020]

Embodiments of the present invention will be described below with reference to FIGS.

First, an embodiment of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing an overall configuration of a heating type fuel supply device. The air from the intake pipe 33 passes through the flow meter 27, passes through the throttle valve 4 or the idle speed control valve 45 that adjusts the intake air during idling and controls the rotation speed, and then is supplied to the engine 42. It Fuel is supplied from the fuel injection valve 1.
The heating type fuel supply device of the present embodiment is provided for the flow of air from the flow meter 27 to the engine 42.
The apparatus includes an air passage 2 for supplying heated air to the fuel injection valve 1, an electric heater 3, a water temperature sensor 46 for measuring the cooling water temperature of the engine 42, and a heating circuit 4 for driving the electric heater 3.
3. It comprises a microcomputer 44.
The engine cooling water temperature detected by the water temperature sensor 46 is transmitted to the microcomputer 44, and the heating circuit 43 and the idle speed control valve 45 operate according to a command from the microcomputer 44 based on this signal.

Next, the flow of intake air in this embodiment is shown in FIG. A part of the intake air in the intake pipe is guided to an air passage 2 for supplying heated air to the fuel injection valve 1 from an inlet provided downstream of the flow meter 27 and upstream of the throttle valve 4, and in the middle of the air passage 2. It is heated by the electric heater 3 provided. By applying the heated air to the fuel injected from the fuel injection valve 1, atomization of the fuel is promoted.

Next, the structure of the tip of the fuel injection valve 1 in this embodiment is shown in FIG. The air heated by the electric heater 3 in the air passage 2 is supplied to the air holes 5. On the other hand, the fuel from the fuel injection valve is injected from the orifice 7 when the ball valve 6 moves up. A heated air flow from the air hole 5 is applied to the injected fuel, and the injected fuel and the heated air are mixed with each other in the mixing chamber
The mixture is mixed in A and the fuel is atomized and vaporized. Then, the atomized fuel is ejected from the ejection holes 8. The injection holes 8 are two holes in the two-intake-valve engine.
It is one hole in an intake valve engine.

Next, the structure of the electric heater 3 in this embodiment will be described with reference to FIG.

The structure of the electric heater 3 is shown in FIG.
The electric heater 3 includes a casing 16, a heating body 9 provided in the center of the casing 16, a heat insulating material 10 arranged around the heating body 9, electrodes 11 and 12 provided at two places, an inlet 14, and a dispersion member 13. , Outlet 15. Air flows in through the inlet 14 and is dispersed by the dispersion member 13 over the entire surface of the heating body 9. The air heated by the heating element 9 is supplied from the outlet 15 to the fuel injection valve 1. The electrodes 11 and 12 of the heating element 9 are taken out from the casing 16. The heating element 9 is composed of a mesh-shaped thin plate 17 made of a mesh-shaped thin plate having a large electric resistance. The mesh-like thin plate 17 is shown in FIG. The net-like thin plate 17 and the insulating material 18 are spirally rolled to form the heating element 9. This state is shown in FIG. Further, at this time, the mesh-like thin plate 17 is corrugated as shown in FIG. 4D so as to reduce the air resistance.

Next, the control procedure of atomization / vaporization of fuel by the microcomputer 44 at the time of engine start and engine cold of this embodiment will be described with reference to FIGS.

FIG. 5 shows the power supply ACC of the auxiliary equipment, the applied voltage VH and the current value IH of the electric heater 3, the key operation K. SW. Shows a time chart of the idle speed control valve 45ISC and the engine cooling water temperature Tw. First, when the driver turns on the power supply ACC for the auxiliary equipment (Fig. 5 (a)), a signal is sent from the microcomputer 44 to the heating circuit 43, the voltage VH is applied to the electric heater 3 and the current IH flows to start heating. (Fig. 5 (b)). The dotted line shows the voltage VH and the solid line shows the current IH. Initially, by increasing the applied voltage VH, the electric heater 3 rises faster. After that, the current value IH
Decreases with an increase in temperature, and when it falls below a certain predetermined value Io, the microcomputer 44 judges that the heating temperature has reached a predetermined value and issues a command for cranking OK. The driver looks at this display and operates the keys K. SW. And cranking is started (Fig. 5 (c)). During this cranking, the idle speed control valve 4 for controlling the idle speed by the command of the microcomputer 44
5 is closed (FIG. 5 (d)), the air sucked into the engine 42 is passed through the air passage 2. As a result, heated air can be sent to the fuel injection valve 1 even during cranking. After that, the cooling water temperature Tw gradually rises as the engine 42 warms up, and when the temperature reaches a predetermined temperature TA, the microcomputer 44 judges that the warming up has ended (Fig. 5 (e)), and the microcomputer 44 sends an electric signal at the command. The voltage application to the heater 3 is stopped (FIG. 5B).

Flow charts of this control procedure by the microcomputer 44 are shown in FIGS. First, in FIG. 6, when the driver turns on the power supply ACC for the auxiliary machinery, VH is applied to the electric heater 3. After that, when the current IH becomes less than or equal to the predetermined value Io, cranking OK is displayed to the driver. When this flow ends, the process moves to the flow shown in FIG. In FIG. 7, the key operation K. SW. When is turned on, cranking is started. As described above, the idle speed control valve 45 remains closed during cranking. When cranking ends and the engine starts, the operation of the idle speed control valve 45 starts. After that, when the cooling water temperature Tw reaches the predetermined temperature TA or less, the application of the voltage VH is stopped, and this flow is ended.

According to the present embodiment configured as described above,
A part of the intake air in the intake pipe is heated by an electric heater 3 provided in the middle of the air passage 2, and this is heated by the fuel injection valve 1
Since it is applied to the fuel injected from, the atomization of the fuel can be promoted. Further, the microcomputer 44 is the engine 4
When heating by the electric heater 3 is started before the cranking of No. 2 is started, the idle speed control valve 45 is operated and closed when the engine 42 is cranked, and when the cooling water temperature Tw of the engine 42 reaches a predetermined temperature To. Since the heating by the electric heater 3 is stopped, it is possible to supply heated air at the time of starting the engine to promote atomization of the fuel. Therefore, the low temperature startability is improved. Further, particularly at a time when the catalyst is not activated, the amount of HC discharged can be reduced, which is effective in purifying exhaust gas. Further, since the electric heater 3 is composed of the mesh-like thin plate 17, it is possible to shorten the heating time and improve the responsiveness while minimizing the flow resistance.

Next, some embodiments of the present invention in which the installation location of the electric heater is different will be described with reference to FIGS.

The electric heater 3 is shown in FIG.
An example in which it is attached to Part of the intake air is introduced into the air passage 25 through an inlet 28 provided downstream of the flow meter 27 and upstream of the throttle valve 4. Electric heater 3
Is integrally provided in the gallery forming the air passage 25, and the air heated by the electric heater 3 is supplied to the fuel injection valves 21 to 24 of each cylinder. According to this embodiment, even in a multi-cylinder engine, heated air under the same condition can be sent to each cylinder, so that the air can be efficiently heated by one electric heater 3.

FIG. 9 shows an embodiment in which the electric heater 29 is provided at the inlet of the fuel injection valve 1 where intake air enters. In this embodiment, an electric heater 29 is provided in the pipe of the air hole 5, and the electric heater 29 heats the intake air. Therefore, since the electric heater 29 can be provided in each of the fuel injection valves 1 of the respective cylinders, the heating temperature can be increased and the effect of vaporizing the fuel becomes large.

FIG. 10 shows an embodiment in which the electric heater 34 is integrated with the intake pipe. In this embodiment, the electric heater 34 and the air passage 31 are integrated in the intake pipe 33. Part of the intake air is from the inlet 32 to the air passage 31
And is heated by the electric heater 34, and then supplied to the tips of the fuel injection valves 21 to 24. According to this embodiment,
With such an integrated structure, a simpler and space-saving device structure is possible.

FIG. 11 shows an embodiment in which the electric heater 36 is provided in the air passage in the fuel injection valve 1. In the present embodiment, the electric heater 36 is provided in the air chamber 35 which is an air passage in the fuel injection valve 1, and the intake air supplied from the air hole 5 is heated by the electric heater 36. Therefore, according to this embodiment, it is not necessary to provide a place for installing the electric heater 3.

Another embodiment of the air supply means of the present invention is shown in FIG. In this embodiment, an air pump 49 is provided in the air passage 2 for supplying a part of the intake air to the fuel injection valve 1, and the air pump 49 and the electric heater 3 are operated by a command of the microcomputer 44 during cranking of the engine to heat the heated air. Supply to the fuel injection valve 1. Therefore, according to this embodiment, the heated air can be reliably supplied to the fuel injection valve 1 when the engine is started.

Yet another embodiment relating to the electric heater of the present invention is shown in FIGS. In the embodiment of FIG. 13, a heating resistance wire 52 is provided in the air passage 51 that guides a part of the intake air, and the air is directly heated by passing through the air passage 51. The heating circuit 52 is energized by the drive circuit 53. Further, the fuel is supplied from the fuel pipe 50 to the fuel injection valve 1.

In the embodiment of FIG. 14, FIG. 14 (a)
As shown in, the pipe itself which constitutes the air passage 60 for guiding a part of the intake air is used as a heating body, electrodes 61a and b are provided at both ends of this pipe, and the drive circuit 62 energizes to heat the pipe. The air passage 60 itself may be made of a metal having a large resistance (FIG. 14B), or a metal 64 having a large resistance value may be provided inside the non-conductive pipe 63 (FIG. 14C). )).

According to the two embodiments shown in FIGS. 13 and 14, the installation space is minimized by directly heating the air by using the pipe itself which constitutes the air passage 60 for guiding a part of the intake air as a heating body. It can be heated with a simple structure that is limited.

[0039]

According to the present invention, it is possible to heat the supply air and accelerate the atomization of the fuel when the engine is started and when the engine is cold, so that the low temperature startability is improved. If the supply air is heated when the catalyst is not activated, HC
The amount of exhaust gas can be reduced, which is effective in purifying exhaust gas.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a flow of intake air.

FIG. 3 is a diagram showing a structure of a tip portion of a fuel injection valve.

FIG. 4 is a diagram showing a configuration of an electric heater.

FIG. 5 is a diagram showing a time chart of each device during control by a microcomputer.

FIG. 6 is a diagram showing a flowchart of a control procedure by a microcomputer.

FIG. 7 is a diagram showing a flowchart of a control procedure by a microcomputer.

FIG. 8 is a diagram showing an example in which an electric heater is integrally provided in a gallery of an air passage.

FIG. 9 is a diagram showing an example in which an electric heater is provided in a pipe having an air hole.

FIG. 10 is a diagram showing an embodiment in which an electric heater and an air passage are integrated in an intake pipe.

FIG. 11 is a diagram showing an embodiment in which an electric heater is provided in an air chamber inside a fuel injection valve.

FIG. 12 is a diagram showing an embodiment in which an air pump is provided in the air passage.

FIG. 13 is a diagram showing an example in which a heating resistance wire is provided in the air passage.

FIG. 14 is a diagram showing an example in which the pipe itself forming the air passage is used as a heating body.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Fuel injection valve 2 Air passage 3 Electric heater 5 Air hole 17 Mesh thin plate 21-24 Fuel injection valve 25 Air passage 29 Electric heater 31 Air passage 33 Intake pipe 34 Electric heater 35 Air chamber 36 Electric heater 44 Microcomputer 45 Idle Speed control valve 46 Water temperature sensor 49 Air pump 51 Air passage 52 Heat generation resistance wire 60 Air passage VH Applied voltage IH Current Io Current specified value Tw Engine cooling water temperature TA Engine cooling water temperature specified value

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Reference number within the agency FI Technical display location F02M 31/12 311 E 69/04 G 9248-3G (72) Inventor Ryoichi Furumuro Hitachi City, Ibaraki Prefecture 4026 Kuji Town, Hitachi Research Laboratory, Nitate Works Co., Ltd. (72) Inventor Toshiharu Nogi 4026 Kuji Town, Hitachi City, Hitachi City, Ibaraki Prefecture (72) Hitachi Research Laboratory, Hitachi Co., Ltd. (72) Mamoru Nemoto, Katsuta City, Ibaraki Prefecture 2477 Kashima Yatsu 3 Hitachi Automotive Engineering Co., Ltd.

Claims (11)

[Claims] 1. A heating type fuel supply device for providing a heating means for heating a part of intake air, and applying the heated air to fuel injected from a fuel injection valve to atomize the fuel,
An electric heater provided as the heating means, and an air supply means for passing a part of the intake air through the electric heater,
A heating type fuel supply device, comprising: a control unit that detects an engine cooling water temperature and operates the electric heater and the air supply unit when the water temperature is equal to or lower than a predetermined temperature. 2. The heating type fuel supply apparatus according to claim 1, wherein the electric heater is composed of a mesh-like thin plate. 3. The heating type fuel supply apparatus according to claim 1, wherein the electric heater is integrated with a gallery forming an air passage for supplying a part of the intake air to a plurality of cylinders. Fuel supply system. 4. The heating type fuel supply apparatus according to claim 1, wherein the electric heater is provided at an inlet portion into which a part of the intake air enters the fuel injection valve. 5. The heating fuel supply device according to claim 1, wherein the electric heater and an air passage for guiding air heated by the electric heater to the fuel injection valve are integrally formed in an intake pipe. Characteristic heating type fuel supply device. 6. The heating fuel supply device according to claim 1, wherein the electric heater is provided in an air passage through which a part of the intake air in the fuel injection valve is introduced. .. 7. The heating type fuel supply apparatus according to claim 1, wherein the control means starts heating by the electric heater before starting cranking of the engine. 8. The heating type fuel supply apparatus according to claim 1, wherein the control means stops the heating by the electric heater when the cooling water temperature of the engine reaches a predetermined temperature. Fuel supply system. 9. The heating fuel supply device according to claim 1, wherein the air supply means is means for closing an idle speed control valve, and the control means operates the idle speed control valve during cranking of the engine. , A heating type fuel supply device characterized by closing it. 10. The heating type fuel supply apparatus according to claim 1, wherein the air supply means is an air pump provided in an air passage for guiding a part of the intake air, and the control means is used when cranking the engine. A heating type fuel supply device characterized in that the pump is operated. 11. The heating type fuel supply apparatus according to claim 1, wherein the electric heater is means for directly heating an air passage for guiding a part of the intake air.