JP4566473B2 - Fuel cooling method in internal combustion engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for cooling liquid fuel for an internal combustion engine for preventing the generation of bubbles due to fuel boiling in a gasoline engine or a diesel engine during a high temperature, high temperature or extreme heat, which is remarkable in summer or a country with a hot climate. is there.
[0002]
[Prior art]
In order to supply fuel to an engine fuel injection device in an internal combustion engine more reliably, a fuel pump is used, and various pump systems have been adopted along with higher engine output and development of fuel injection devices. However, especially in the summer or when the climate is hot, during high temperatures and high temperatures, or during extreme heat, liquid fuel is transferred by heat transfer from the engine and exhaust system components during the process of being delivered from the fuel tank to the fuel injector. When the temperature becomes high and the fuel temperature exceeds the boiling point, bubbles (vapor) start to be generated in the fuel liquid. When bubbles are generated in the fuel liquid, the bubbles are mixed into the fuel liquid injected into the cylinder by the fuel injection device, and the amount of fuel injected per injection time is reduced, resulting in a problem that a predetermined output cannot be obtained. was there. The surplus fuel that has not been burned by the engine is returned to the tank via the return pipe, but once it passes near the high temperature part of the engine, it is heated to become hot return fuel, and eventually all the fuel in the tank The temperature of the tank was raised, and vapor was discharged from the tank, which could cause problems due to air pollution and fuel smell in the cabin. In addition, in a pressure accumulation fuel injection system using a diesel engine, in particular, a common rail, since the pressure is extremely high, raising the temperature of the return fuel becomes a problem.
[0003]
As a countermeasure in a gasoline engine, conventionally, a method of cooling a fuel supply pipe between a fuel tank and a fuel injection device with a pipe of an air conditioner (air conditioner) of an automobile to lower the fuel temperature below the boiling point has been taken. In addition, in the case of a diesel engine adopting a pressure accumulation fuel injection system using a common rail, the current situation is that the fuel is not cooled at all.
However, the method of lowering the fuel temperature using an air conditioner leads to an increase in the size of the compressor and condenser of the air conditioner and the deterioration of fuel consumption, and the fuel temperature can be lowered only when the air conditioner is driven. There is a disadvantage that the fuel temperature cannot be lowered when the engine is stopped. In the case of a diesel engine, the fuel is not cooled at all in the piping of an accumulator fuel injection system that uses a common rail, so the heat deterioration of tank parts (such as hoses) made of heat-resistant resin is unavoidable. is there.
[0004]
[Problems to be solved by the invention]
The present invention has been made to solve the above-mentioned conventional problems. Regardless of whether the air conditioner or the heat exchanger is driven or not driven, the fuel temperature can be set as needed without deteriorating the fuel consumption during driving. An object of the present invention is to propose a fuel cooling method that can be lowered below the boiling point and that can be efficiently cooled by a relatively simple means even in an accumulator fuel injection system using a common rail.
[0005]
[Means for Solving the Problems]
The present invention provides a fuel cooling means for preventing the generation of fuel boiling bubbles due to a rise in the temperature of liquid fuel in an internal combustion engine. The first invention provides heat for lowering the fuel temperature below the boiling bubble generation temperature in the middle of the fuel pipe. An exchanger, the heat exchanger is a sealed container, a fuel pipe that is piped through the sealed container and has a capillary structure on the surface of the pipe in the container, and an inside of the sealed container A heat medium fluid and a cooling part enclosed in the sealed container, while the heat medium fluid in the sealed container rises due to surface tension in the capillary of the wick material, in the fuel pipe penetrating the sealed container The fuel is evaporated by the heat energy of the high-temperature fuel, the temperature of the fuel is lowered below the boiling bubble generation temperature by the latent heat of vaporization at that time, and the evaporation flow of the heat transfer fluid is condensed in the cooling section and returned to the original heat transfer fluid. According to the second aspect of the present invention, a heat exchanger for lowering the fuel temperature to below the boiling bubble generation temperature is disposed in the middle of the fuel pipe, and the heat exchanger includes a sealed container and a sealed container. It is composed of a fuel pipe which is piped through and a wick material having a capillary structure is attached to the surface of the pipe in the container, and a suction part to the outside of the evaporation flow of the heat medium fluid sealed in the sealed container, While the heat transfer fluid in the sealed container rises due to surface tension in the capillary of the wick material, it evaporates by the thermal energy of the high-temperature fuel in the fuel pipe passing through the sealed container, and the latent heat of vaporization at that time The temperature of the fuel is lowered below the boiling bubble generation temperature, and the evaporated flow of the heat medium fluid is sucked to the outside from the suction portion, and the suction portion to the outside is an intake manifold It is characterized in that it is field. As the heat medium fluid, any one of gasoline, light oil, water, a mixed liquid of water and alcohol, a mixed liquid of water and ether, chlorofluorocarbon, or alternative chlorofluorocarbon can be used.
[0006]
That is, the heat exchanger in the present invention utilizes the latent heat of vaporization of the heat medium fluid, and the heat energy of the high-temperature fuel is increased while the heat medium fluid in the sealed container rises in the capillary of the wick material due to surface tension. When the evaporation pressure of the heating unit space is reduced by the action of the cooling unit and the suction unit, the evaporation is promoted to take the latent heat of vaporization and cool the fuel pipe, and the heating medium fluid The evaporative flow flows to a cooling part having a low pressure, is cooled and condensed, and returns to the original liquid, or is sucked to the outside. Therefore, according to this heat exchanger, it is possible to lower the temperature of the fuel below the boiling bubble generation temperature as needed, regardless of whether the air conditioner is driven or not, and the temperature of the liquid fuel in the gasoline engine or diesel engine By preventing the occurrence of fuel boiling bubbles due to ascending, bubbles are not mixed into the fuel injected into the cylinder by the fuel injection device, and the fuel injection amount per injection time is always properly set. It becomes possible to keep.
In the present invention, the heat exchanger as described above is used in order to suppress the increase in the size of the compressor and condenser of the air conditioner and the increase in fuel consumption, and also in the accumulator fuel injection system using the common rail. This is to solve the problem.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic view showing a first embodiment apparatus for carrying out the method of the present invention, FIG. 2 is a schematic view showing the second embodiment apparatus, and FIG. 3 is a schematic view showing the third embodiment apparatus. 1A, 1B, 1C, 11A, 11B, 11C, 31A, 31B, 31C are fuel pipes, 2, 12 are heat exchangers, 3, 13 are fuel tanks, 4, 14 are wick materials, 5, 15 Is a fuel, 6 is a heat medium fluid (liquid), 7 and 17 are heat medium fluid pipes, 8 and 18 are fuel pumps, 9 and 29 are fuel injection devices, 10 is an evaporative flow pipe, 20 is an intake manifold, and 21 is a cylinder The head, 22 is an intake valve, 23 is a valve stem, 24 is a piston, 25 is a combustion chamber, 26 is a cylinder block, 30 is a high pressure pump, 32 is a common rail, and V1 to V4 are on-off valves.
[0008]
In FIG. 1, a heat exchanger 2 is disposed in the middle of a fuel pipe 1B branched and connected to a fuel pipe 1A between a fuel tank 3 and a fuel injector 9, and the structure thereof is a sealed container 2-1 and the container. A pipe 2-2 communicating between the top and the bottom, a cooling part 2-4 in which a part of the pipe is a fin tube 2-3, a heat medium fluid 6 sealed in the sealed container 2-1, and a sealed container 2 -1 and a fuel pipe 1B in which a wick material 4 having a capillary structure is attached to the surface of the pipe in the container, and a heat medium fluid pipe 7 connected to the bottom of the sealed container 2-1. The heat medium fluid 6 is injected into the sealed container 2-1 through the on-off valve V1. Further, cooling air is applied to the cooling unit 2-4 configured by the fin tube 2-3 from the outside as indicated by an arrow, and the evaporation flow in the fin tube 2-3 is condensed to the original liquid. It is a mechanism to return. The other end of the fuel pipe 1B that penetrates the sealed container 2-1 is connected to the fuel pipe 1A via the on-off valve V2, so that the fuel cooled by the heat exchanger 2 is supplied to the fuel injection device 9. It is piped in. The fuel injection device 9 includes a delivery pipe 9-1 and an injector 9-2. In consideration of the case where it is not necessary to cool the fuel, an on-off valve V3 is provided in the fuel pipe 1A.
[0009]
In the above device configuration, the fuel (gasoline) 5 in the fuel tank 3 is supplied to the fuel injection device 9 by the fuel pump 8 via the fuel pipe 1A or 1B. In this case, when the outside air temperature is high and the temperature of the fuel supplied to the fuel injection device 9 rises above the boiling point and may cause boiling, the on-off valve V3 on the fuel pipe 1A side is closed and the fuel pipe 1B is closed. The on-off valve V2 on the side is opened to allow the fuel 5 in the fuel tank 3 to flow through the heat exchanger 2. At this time, the heat medium fluid 6 supplied from the heat medium fluid pipe 7 through the on-off valve V1 and sealed in the sealed container 2-1 is caused to cause the surface tension of the heat medium fluid 6 in the capillary of the wick material 4. And is evaporated by being heated by the thermal energy of the high-temperature fuel in the fuel pipe 1B, and the evaporation flow is constituted by the fin tube 2-3 through the pipe 2-2 from the top of the sealed container 2-1. Then, it is condensed by the cooling unit 2-4, returns to the original heat medium fluid 6, and circulates and flows into the sealed container 2-1. On the other hand, the fuel flowing in the fuel pipe 1B is deprived of heat by the evaporation of the heat medium fluid 6 in the heat exchanger 2 and is supplied to the fuel injection device 9 below the bubble generation temperature. Therefore, bubbles are not mixed in the fuel injected into the cylinder by the fuel injection device 9, and the fuel injection amount per injection time can always be kept appropriate.
[0010]
On the other hand, when the outside air temperature is low and the temperature of the fuel supplied to the fuel injection device 9 is lower than the bubble generation temperature, there is no need to lower the fuel temperature, so the on-off valve V2 on the fuel pipe 1B side is closed and the fuel pipe 1A is closed. The on-off valve V3 is opened and fuel is directly supplied to the fuel injection device 9 from the fuel pipe 1A.
[0011]
Next, FIG. 2 exemplifies a system in which the fuel 15 is used as a heat medium fluid, and this fuel is sucked into the intake manifold 20 as an evaporating flow. The heat exchanger 12 supplies a high-temperature return fuel from the engine to the fuel tank 13. The fuel pipe 11A is arranged in the middle of the fuel pipe 11A, and the structure is piped through the sealed container 12-1, the fuel 15 sealed in the sealed container 12-1, and the sealed container 12-1. The fuel pipe 11A-1 is a fuel pipe 11A-1 with a wick material 14 having a capillary structure on the surface of the pipe in the container. The fuel pipe is branched in the middle of the fuel pipe 11B for supplying the fuel 15 in the fuel tank 13 to the engine. From 11C, the fuel 15 is injected into the sealed container 2-1 through the on-off valve V4. The other end of the evaporative flow pipe 10 connected to the top of the hermetic container 12-1 is connected to the intake manifold 20, and the evaporative flow is sucked into the intake manifold 20.
When water other than fuel, for example, water is used as the heat medium fluid, the heat medium fluid pipe 17 is connected to the sealed container 12-1, and the on-off valve V4 of the fuel pipe 11C is closed, or the fuel pipe 11C and the on-off valve V4. Can be abolished and water can be supplied from the heat medium fluid pipe 17 into the sealed container 12-1.
[0012]
In the apparatus shown in FIG. 2, the fuel (gasoline) 15 in the fuel tank 13 is supplied to the engine by the fuel pump 18 via the fuel pipe 11B. At this time, the on-off valve V4 of the fuel pipe 11C is in a closed state, and a certain amount of fuel 15 is stored in the sealed container 12-1. Of the fuel 15 supplied to the engine, the high-temperature return fuel from the engine flows through the heat exchanger 12 through the fuel pipe 11A and returns to the fuel tank 13 for circulation. When passing through the sealed container 12-1, the fuel 15 sealed in the sealed container 12-1 rises in the capillary of the wick material 14 due to the surface tension of the fuel 15, and the sealed container 12-1 The fuel pipe 11A-1 is heated and evaporated by the heat energy of the high-temperature fuel in the fuel pipe 11A-1, and the evaporated flow is sucked into the intake manifold 20 from the top of the sealed container 12-1 through the evaporation flow pipe 10. . On the other hand, the fuel flowing through the fuel pipe 11A-1 is deprived of heat by the evaporation of the fuel 15 in the sealed container 12-1 and is supplied to the fuel tank 13 below the boiling temperature.
[0013]
Further, FIG. 3 is an example in which the apparatus configuration shown in FIG. 1 is applied to an accumulator fuel injection system (diesel engine) using a common rail, and is the same as the apparatus configuration shown in FIG. is there.
That is, FIG. 3 is a diagram in which an accumulator fuel injection system including a high pressure pump 30, high pressure fuel pipes 31A, 31B, 31C, a common rail 32, a fuel injection device (injector) 29, and the like is connected to the fuel injection device 9 by piping. In this case as well, when the temperature of the fuel (light oil) supplied to the fuel injection device 29 is high above the boiling point and there is a risk of boiling, the on-off valve V3 on the fuel pipe 1A side is closed. Then, the on-off valve V2 on the fuel pipe 1B side is opened to allow the fuel 5 in the fuel tank 3 to flow through the heat exchanger 2. At this time, the heat medium fluid 6 supplied from the heat medium fluid pipe 7 through the on-off valve V1 and sealed in the sealed container 2-1 is caused to cause the surface tension of the heat medium fluid 6 in the capillary of the wick material 4. And is evaporated by being heated by the thermal energy of the high-temperature fuel in the fuel pipe 1B, and the evaporation flow is constituted by the fin tube 2-3 through the pipe 2-2 from the top of the sealed container 2-1. Then, it is condensed by the cooling unit 2-4, returns to the original heat medium fluid 6, and circulates and flows into the sealed container 2-1. On the other hand, the fuel flowing in the fuel pipe 1B is deprived of heat by the evaporation of the heat medium fluid 6 in the heat exchanger 2 and becomes less than the bubble generation temperature, and is supplied to the pressure accumulation fuel injection system side. The pressure is increased to a predetermined pressure and supplied to the common rail 32, supplied to the injector 29 from the fuel pipe 31C (injection pipe), and injected into each cylinder. Therefore, bubbles are not mixed into the fuel injected into the cylinder by the injector 29, and the fuel injection amount per injection time can always be kept appropriate.
[0014]
In the present invention, the apparatus shown in FIG. 1 and the apparatus shown in FIG. 2 are combined, and when the engine is operating and the vehicle is stopped, the fuel is cooled by the suction method shown in FIG. During traveling, it is also possible to cool with the heat exchanger 2 shown in FIG. As described above, the heat medium fluid 6 enclosed in the sealed container 2-1 of the heat exchanger 2 includes gasoline, light oil, water, a mixed liquid of water and alcohol, a mixed liquid of water and ether, chlorofluorocarbon, and alternative chlorofluorocarbon. Either of these can be used.
[0015]
【The invention's effect】
As described above, according to the method of the present invention, the use of a heat exchanger that lowers the fuel temperature by using the thermal energy of the liquid fuel flowing through the fuel pipe enables driving of an automobile, driving or non-driving of an air conditioner. Regardless of the fuel temperature, the fuel temperature can be lowered to below the boiling bubble generation temperature as necessary, so that it is possible to prevent the occurrence of fuel boiling bubbles due to the temperature rise of the liquid fuel (gasoline, light oil, etc.) of the internal combustion engine. As a result, bubbles are not mixed into the fuel injected into the cylinder by the fuel injection device, so that the fuel injection amount per injection time can always be kept appropriate. In addition, in the case of a diesel engine that employs an accumulator fuel injection system that uses a common rail, the life of tank parts (resin parts, comb hoses, resin tanks, etc.) can be extended. Therefore, the present invention is extremely effective for a high-temperature, high-heated area specification vehicle particularly in summer or in a country with a hot climate.
[Brief description of the drawings]
FIG. 1 is a schematic view showing a first embodiment apparatus for carrying out the method of the present invention.
FIG. 2 is a schematic view showing a second embodiment apparatus for carrying out the method of the present invention.
FIG. 3 is a schematic view showing a third embodiment apparatus for carrying out the method of the present invention.
[Explanation of symbols]
1A, 1B, 1C, 11A, 11B, 11C, 31A, 31B, 31C Fuel piping 2, 12 Heat exchanger 3, 13 Fuel tank 4, 14 Wick material 5, 15 Fuel 6 Heat medium fluid 7, 17 Heat medium fluid piping 8, 18 Fuel pump 9 Fuel injection device 10 Evaporative flow pipe 20 Intake manifold 21 Cylinder head 22 Intake valve 23 Valve stem 24 Piston 25 Combustion chamber 26 Cylinder block 29 Injector 30 High-pressure pump 32 Common rail V1-V4 On-off valve

Claims (4)

A fuel cooling method for preventing the generation of fuel boiling bubbles due to a rise in the temperature of fuel in an internal combustion engine, comprising a heat exchanger for lowering the fuel temperature below the boiling bubble generation temperature in the middle of a fuel pipe, The heat exchanger includes a sealed container, a fuel pipe that is piped through the sealed container and has a capillary structure on the surface of the pipe in the container, and a heat medium fluid sealed in the sealed container And a cooling unit, while the heat medium fluid in the sealed container rises due to surface tension in the capillary of the wick material, by the thermal energy of the high-temperature fuel in the fuel pipe passing through the sealed container The temperature of the fuel evaporates, the temperature of the fuel is lowered below the boiling bubble generation temperature by the latent heat of vaporization at that time, and the evaporative flow of the heat medium fluid is condensed in the cooling unit and returned to the original heat medium fluid. Fuel cooling method in an internal combustion engine to be. A fuel cooling method for preventing the generation of fuel boiling bubbles due to a rise in the temperature of fuel in an internal combustion engine, comprising a heat exchanger for lowering the fuel temperature below the boiling bubble generation temperature in the middle of a fuel pipe, The heat exchanger includes a sealed container, a fuel pipe that is piped through the sealed container and has a capillary structure on the surface of the pipe in the container, and a heat medium fluid sealed in the sealed container And the heat medium fluid in the sealed container rises due to surface tension in the capillary tube of the wick material, and the high temperature in the fuel pipe passing through the sealed container. It is evaporated by the heat energy of the fuel, and the temperature of the fuel is lowered below the boiling bubble generation temperature by the latent heat of vaporization at that time, and the evaporated flow of the heat medium fluid is sucked to the outside from the suction part. Fuel cooling method in an internal combustion engine according to symptoms. The fuel cooling method for an internal combustion engine according to claim 2, wherein the suction portion to the outside is an intake manifold. Any one of claims 1 to 3, wherein gasoline, light oil, water, a mixed liquid of water and alcohol, a mixed liquid of water and ether, chlorofluorocarbon, or alternative chlorofluorocarbon is used as the heat medium fluid. A fuel cooling method for an internal combustion engine according to claim 1.

Images