JPH09264228A - Deicing device for fuel injection valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent icing of water and the like in an injection hole part in a fuel injection valve by quickly increasing a fuel temperature just after a start of engine operation. SOLUTION: A fuel stored in a fuel tank 1 is fed to each fuel injection valve 4 via a feed pipe 3 in which a fuel pump 2 is arranged, and excessive fuel, which is not jetted in the fuel injection valve 4, is returned to the fuel 1 via a return pipe 6 in which a pressure regulator 5 is arranged. In addition, a thermo valve 7, which introduces the excessive fuel to a feed side of the fuel pump 2 if the fuel temperature is the predetermined value or less and introduces the excessive fuel to the fuel tank 1 if the fuel temperature is more than the predetermined value, is arranged in the return pipe 6 inside the fuel tank 1. In this way, excessive fuel receiving heat via the fuel injection valve 4 is circulated inside the fuel supply system when the fuel temperature is the predetermined valve or less, so that the temperature in the tip end part of the fuel injection valve 4 can be increased quickly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-icing device for a fuel injection valve, and more particularly to a technique for rapidly raising the temperature of the tip of the fuel injection valve.

[0002]

2. Description of the Related Art Conventionally, when fuel is injected from a fuel injection valve of an internal combustion engine, the tip portion of the fuel injection valve is cooled by latent heat of vaporization of the fuel, especially when the outside air temperature is low. It is known that the water contained therein adheres to the tip of the fuel injection valve in the form of frost. In this case, when the engine is stopped, the temperature of the fuel injection valve once rises due to the residual heat of the engine, and the moisture adhering to the tip of the fuel injection valve in the form of frost melts, but since the outside air temperature is low, When the temperature of the fuel injection valve drops below the freezing point, re-freezing occurs. At this time, if water is frozen in the injection hole of the fuel injection valve, the fuel supply may be insufficient at the time of starting the engine, which may make it difficult to start the engine.

Therefore, a heater is provided in the vicinity of the injection hole of the fuel injection valve to heat the injection hole and prevent the water from adhering to the injection hole in the form of frost. An anti-icing device for a fuel injection valve, which has a high temperature, has been proposed (see JP-A-5-44604).

[0004]

By the way, as shown in FIGS. 4 and 5, the temperature of the tip portion of the fuel injection valve is closely related to the fuel amount and the fuel temperature in the fuel tank. That is, when the amount of fuel in the fuel tank is large, the rate of rise in fuel temperature is slow because the heat capacity of the fuel supply system is large (see FIG. 4), and the temperature at the tip of the fuel injection valve is (See FIG. 5). In short, the temperature of the tip of the fuel injection valve is governed by the fuel temperature.

However, in the conventional anti-icing device for a fuel injection valve, the temperature of the tip of the fuel injection valve is made higher than the temperature in the intake passage so that the water content in the intake air is injected. Since frost-like adhesion to the tip of the valve was prevented, for example, when the fuel temperature was a low temperature below the freezing point, the fuel injection valve might not be sufficiently prevented from freezing.

In view of the above conventional problems, therefore, the present invention raises the temperature of the fuel injection valve immediately after the start of engine operation to raise the temperature of the tip of the fuel injection valve.
Therefore, it is an object of the present invention to provide an anti-icing device for a fuel injection valve, which prevents freezing of water in the injection hole of the fuel injection valve.

[0007]

Therefore, the invention according to claim 1 is an anti-icing device for a fuel injection valve for supplying fuel to an internal combustion engine, the fuel tank storing the fuel, and the fuel tank. A fuel supply pipe that communicates with the fuel injection valve, a fuel pump that is interposed in the fuel supply pipe, and pumps fuel from the fuel tank to the fuel injection valve, and an excess fuel that is supplied to the fuel injection valve. A fuel return pipe for returning to the fuel tank and a fuel temperature raising means for raising the temperature of the fuel supplied to the fuel injection valve when the temperature of the fuel is equal to or lower than a predetermined value.

According to a second aspect of the present invention, the fuel temperature raising means uses the combustion heat of the internal combustion engine to raise the temperature of the fuel supplied to the fuel injection valve. According to a third aspect of the present invention, the fuel temperature raising means is provided in the fuel return pipe, and when the temperature of the fuel supplied to the fuel injection valve is equal to or lower than a predetermined value, the excess fuel is removed from the fuel pump. The temperature sensitive switching means for guiding the excess fuel to the fuel tank when the fuel temperature is higher than a predetermined value.

According to a fourth aspect of the present invention, the fuel temperature raising means introduces cooling water for cooling the internal combustion engine to the fuel supply pipe to exchange heat with the fuel in the fuel supply pipe, Temperature-sensitive opening / closing means which is interposed in the cooling water pipe, opens the cooling water pipe when the cooling water temperature is below a predetermined value, and closes the cooling water pipe when the cooling water temperature is above a predetermined value. , And are configured to include.

According to a fifth aspect of the present invention, the fuel temperature raising means is configured to raise the temperature of the fuel supplied to the fuel injection valve by utilizing an electric heating type heating means. According to a sixth aspect of the present invention, the fuel temperature raising means serves as the heating means.
An electrothermal heater disposed in the fuel supply pipe to heat the temperature of the fuel supplied to the fuel injection valve, and a fuel temperature detection means for detecting the temperature of the fuel in the fuel supply pipe,
And a heater drive control means for controlling the drive of the electrothermal heater based on the detected fuel temperature.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a diagram showing a first embodiment of an anti-icing device according to the present invention. The fuel pumped from the fuel pump 2 provided in the fuel tank 1 is supplied to each fuel injection valve 4 through a fuel feed pipe (fuel supply pipe) 3. A pressure regulator 5 is disposed downstream of the fuel injection valve 4 so that a differential pressure between a suction negative pressure introduced from an intake pipe of an engine (not shown) and a fuel pressure (hereinafter referred to as “fuel pressure”) is constant. Fuel tank 1
Opening and closing the return pipe (fuel return pipe) 6 for returning to. That is, the action of the pressure regulator 5 is to reduce the fuel pressure by returning the fuel to the fuel tank 1 through the return pipe 6 when the differential pressure is larger than a predetermined value.
When the differential pressure is equal to or lower than the predetermined value, the return pipe 6 is closed to increase the fuel pressure.

The fuel injection valve 4 is an electromagnetic fuel injection valve which is opened by energizing a solenoid and closed by stopping energization, and is opened in response to an injection pulse signal from a control unit (not shown). Then, the fuel adjusted to a predetermined pressure by the pressure regulator 5 is injected and supplied to the intake port of the engine. Further, in the return pipe 6 in the fuel tank 1, a thermo valve (fuel temperature raising means, temperature sensitive switching means) 7 controlled based on the fuel temperature is interposed. This thermo-valve 7 is a so-called three-way valve that guides excess fuel to the feed side of the fuel pump 2 when the fuel temperature is below a predetermined value and guides excess fuel to the fuel tank 1 when the fuel temperature is above a predetermined value. Function as. The thermo valve 7 may be any valve as long as it is a temperature-sensitive valve that operates based on the fuel temperature, and specific examples thereof include a wax type valve and a bimetal type valve. Alternatively, an electromagnetic valve or the like that operates according to the output from the temperature sensor may be used.

According to the anti-icing device for a fuel injection valve having such a structure, when the fuel temperature is below a predetermined value, the surplus fuel which has received the heat of combustion of the engine due to the action of the thermo valve 7 is stored in the fuel pump 2. By being guided to the feed side and mixed with the low temperature fuel supplied from the fuel tank 1, the temperature of the fuel supplied to the fuel injection valve 4 is raised above the fuel temperature in the fuel tank 1. As a result, the temperature of the tip portion of the fuel injection valve 4 can be quickly raised regardless of the fuel temperature in the fuel tank 1, and the moisture contained in the intake air is frosted on the tip portion of the fuel injection valve 4. Is prevented from adhering to
Water is prevented from being frozen in the injection hole portion of the fuel injection valve 4 after the engine is stopped. On the other hand, when the fuel temperature is higher than the predetermined value, the surplus fuel is directly returned to the fuel tank 1 by the action of the thermovalve 7, so that the temperature of the fuel supplied to the fuel injection valve 5 is kept within the fuel tank 1. Above the fuel temperature, which reduces the occurrence of vapor locks, etc.
A stable fuel supply can be performed.

FIG. 2 shows a second anti-icing device according to the present invention.
It is a figure showing an example. In the present embodiment, the engine cooling water is effectively used to raise the temperature of the fuel supplied to the fuel injection valve 4. That is, the cooling water that has received the combustion heat of the engine (not shown) is supplied to the thermo valve 10 (temperature-sensitive opening / closing means).
It is guided to the periphery of the fuel injection valve 4 through the cooling water pipe 11 in which the cooling water pipe 11 is inserted, and the cooling water pipe 11 and the feed pipe 3 are brought into contact with each other, or the feed pipe 3 is passed inside the cooling water pipe 11 (feed The configuration may be such that the cooling water pipe 11 is passed through the inside of the pipe 3), so that heat is exchanged between the cooling water in the cooling water pipe 11 and the fuel in the feed pipe 3 and is supplied to the fuel injection valve 4. Raise the fuel temperature.

Further, the temperature of the cooling water of the thermovalve 10 installed in the cooling water pipe 11 is a predetermined value (for example, 50 ° C.).
By opening the cooling water pipe 11 at the following times and operating to close the cooling water pipe 11 when the cooling water temperature is higher than a predetermined value, it is possible to prevent the fuel temperature from being raised more than necessary. Reduces the occurrence of vapor lock. The thermo-valve 10 in this embodiment may be any valve as long as it is a temperature-sensitive valve that operates based on the temperature of the cooling water, and specifically, a wax-type valve, a bimetal-type valve, etc. may be mentioned. Alternatively, an electromagnetic valve or the like that operates according to the output from the temperature sensor may be used. Here, the fuel temperature raising means is configured to include the thermo valve 10 and the cooling water pipe 11.

According to the anti-icing device for a fuel injection valve having such a structure, the cooling water having a high temperature rising speed for directly receiving the combustion heat of the engine is guided to the feed pipe 3 around the fuel injection valve 4 and cooled. By exchanging heat between the water and the fuel, the temperature of the fuel supplied to the fuel injection valve 4 can be quickly raised. As a result, the temperature of the tip portion of the fuel injection valve 4 also rises quickly, moisture contained in the intake air is prevented from adhering to the tip portion of the fuel injection valve 4 in a frosted state, and the fuel injection is performed after the engine is stopped. Water is prevented from being frozen in the injection hole portion of the valve 4. Further, since the temperature of the fuel supplied to the fuel injection valve 4 is prevented from being raised more than necessary by the action of the thermo valve 10, it is possible to reduce the occurrence of vapor lock and the like and to perform the stable fuel supply. it can.

FIG. 3 shows a third example of the anti-icing device according to the present invention.
It is a figure showing an example. In the present embodiment, the electric heater 20 (heating means) is used to raise the temperature of the fuel supplied to the fuel injection valve 4. That is, the feed pipe 3 around the fuel injection valve 4 is provided with an electrothermal heater 20 driven by the battery 21, and is installed in the feed pipe 3 to detect a fuel temperature (fuel temperature sensor). means)
Based on the output from 22, the switching circuit (heater drive control means) 23 controls energization of the electrothermal heater 20 to heat the fuel. The switching circuit 23 functions to energize the electric heater 20 when the detected fuel temperature is equal to or lower than a predetermined value. It should be noted that a fuel temperature raising means is constituted by including the electric heater 20, the fuel temperature sensor 22, and the switching circuit 23. Further, the switching circuit 23 may be configured by the function of a control unit that incorporates a microcomputer.

According to the anti-icing device for a fuel injection valve having such a structure, when the temperature of the fuel supplied to the fuel injection valve 4 is below a predetermined value, the fuel is heated by the electrothermal heater 20 to The temperature rises quickly. As a result, the temperature of the tip portion of the fuel injection valve 4 rapidly rises, moisture contained in the intake air is prevented from adhering to the tip portion of the fuel injection valve 4 in a frosted state, and the fuel injection is performed after the engine is stopped. Water is prevented from being frozen in the injection hole portion of the valve 4. Further, since the electrothermal heater 20 is controlled based on the fuel temperature, it is possible to prevent battery consumption as much as possible.

In this embodiment, the first to third embodiments are individually described, but in an actual fuel injection valve anti-icing device, two or more devices of arbitrary embodiments are combined. It may be configured. In this case, the fuel temperature can be raised more quickly, so that, for example, an anti-icing device for cold district specifications can be provided.

[0020]

As described above, according to the invention described in claim 1, when the temperature of the fuel supplied to the fuel injection valve is equal to or lower than a predetermined value, the fuel is rapidly raised by the fuel temperature raising means. Since it is heated, it is possible to reduce the moisture contained in the intake air from adhering to the tip portion of the fuel injection valve in a frosted state, and to prevent the moisture from being frozen in the injection hole portion of the fuel injection valve after the engine is stopped. As a result, even when the outside air temperature is low, insufficient fuel supply does not occur at the time of starting the engine, and the engine can be started stably.

According to the second aspect of the present invention, the temperature of the fuel supplied to the fuel injection valve is raised by utilizing the combustion heat of the internal combustion engine, so that it is not necessary to newly provide a heat source and the cost is increased. Etc. can be suppressed as much as possible. According to the invention described in claim 3, when the temperature of the fuel supplied to the fuel injection valve is equal to or lower than a predetermined value, the surplus fuel is introduced to the feed side of the fuel pump and mixed with the low temperature fuel supplied from the fuel tank. Since the so-called circulation path is configured, the temperature of the fuel supplied to the fuel injection valve can be quickly raised regardless of the fuel temperature in the fuel tank. Further, when the fuel temperature is higher than the predetermined value, excess fuel is prevented from being introduced to the fuel tank and the temperature of the fuel supplied to the fuel injection valve is prevented from rising more than necessary, and the occurrence of vapor lock or the like is reduced. Therefore, stable fuel supply can be performed.

According to the fourth aspect of the invention, the cooling water whose temperature rises promptly is guided to the fuel supply pipe to exchange heat with the fuel in the fuel supply pipe, so that it is supplied to the fuel injection valve. It is possible to quickly raise the temperature of the fuel to be discharged. When the cooling water temperature is higher than the predetermined value,
Since the cooling water is not guided to the fuel supply pipe by the temperature-sensitive opening / closing means, the temperature of the fuel supplied to the fuel injection valve is prevented from being raised more than necessary, and the occurrence of vapor lock or the like is reduced and stabilized. Fuel can be supplied.

According to the fifth aspect of the invention, since the temperature of the fuel supplied to the fuel injection valve is raised by utilizing the electrothermal heater, it is not necessary to provide complicated piping or the like, and the structure is simple. can do. According to the invention described in claim 6,
When the temperature of the fuel supplied to the fuel injection valve is equal to or lower than the predetermined value, the fuel is heated by the electrothermal heater, and the fuel temperature can be quickly raised. Further, since the electric heater is controlled based on the fuel temperature, it is possible to prevent the consumption of the battery as much as possible.

[Brief description of drawings]

FIG. 1 is a diagram showing a first embodiment of an anti-icing device according to the present invention.

FIG. 2 is a diagram showing a second embodiment of the above.

FIG. 3 is a diagram showing a third embodiment of the above.

FIG. 4 is a diagram showing the relationship between the temperature of the tip of the fuel injection valve and the amount of fuel in the tank.

FIG. 5 is a diagram showing the relationship between the temperature of the tip of the fuel injection valve and the fuel temperature.

[Explanation of symbols]

 1 Fuel Tank 2 Fuel Pump 3 Feed Pipe 4 Fuel Injection Valve 5 Pressure Regulator 6 Return Pipe 7 Thermo Valve 10 Thermo Valve 11 Cooling Water Pipe 20 Electric Heater 21 Battery 22 Fuel Temperature Sensor 23 Switching Circuit

Claims (6)

[Claims] 1. An anti-icing device for a fuel injection valve for supplying fuel to an internal combustion engine, comprising: a fuel tank for storing fuel; a fuel supply pipe for connecting the fuel tank and the fuel injection valve; A fuel pump, which is interposed in a supply pipe and pressure-feeds fuel from the fuel tank to the fuel injection valve, a fuel return pipe for returning surplus fuel supplied to the fuel injection valve to the fuel tank, and a fuel supply pipe for supplying the fuel to the fuel injection valve. When the temperature of the fuel to be
A fuel injection valve anti-icing device, comprising: a fuel temperature raising means for raising the fuel temperature. 2. The fuel injection valve according to claim 1, wherein the fuel temperature raising means raises the temperature of the fuel supplied to the fuel injection valve by utilizing the combustion heat of the internal combustion engine. Anti-icing device. 3. The fuel temperature raising means is provided in the fuel return pipe, and when the temperature of the fuel supplied to the fuel injection valve is equal to or lower than a predetermined value, the surplus fuel is fed to the feed side of the fuel pump. 3. The anti-icing device for a fuel injection valve according to claim 2, further comprising temperature sensitive switching means for guiding the surplus fuel to the fuel tank when the fuel temperature is higher than a predetermined value. 4. The fuel temperature raising means introduces cooling water for cooling the internal combustion engine to the fuel supply pipe and exchanges heat with the fuel in the fuel supply pipe, and a cooling water pipe through the cooling water pipe. And a temperature-sensitive opening / closing means for opening the cooling water pipe when the cooling water temperature is equal to or lower than a predetermined value and closing the cooling water pipe when the cooling water temperature is higher than the predetermined value. The anti-icing device for a fuel injection valve according to claim 2, wherein: 5. The freezing of the fuel injection valve according to claim 1, wherein the fuel temperature raising means raises the temperature of the fuel supplied to the fuel injection valve by utilizing an electrothermal heating means. Prevention device. 6. The fuel temperature raising means includes, as the heating means, an electrothermal heater arranged in the fuel supply pipe for heating the temperature of fuel supplied to the fuel injection valve, and the fuel supply pipe. 6. A fuel temperature detection means for detecting the temperature of the fuel inside, and a heater drive control means for controlling the drive of the electrothermal heater based on the detected fuel temperature. The anti-icing device for a fuel injection valve described.