JP4715800B2 - Fuel cooling device - Google Patents

Description

The present invention relates to a vehicle including an internal combustion engine that uses liquefied gas fuel such as LPG (liquefied petroleum gas) as a fuel, and in particular, liquefied gas fuel is obtained by performing heat exchange between the liquefied gas fuel and a refrigerant. on the fuel cooling device cool.

  As fuel for an internal combustion engine (engine) of a vehicle, there is liquefied gas fuel such as LPG which is easily liquefied by being compressed. In engines using this liquefied gas fuel, fuel injection engines (hereinafter referred to as engines) in which liquefied gas fuel that has been pressurized to a predetermined jet pressure by a high-pressure pump or the like is ejected from an injector are becoming widespread.

  Some vehicles using this engine collect liquefied gas fuel surplus in an injector in a liquid container (fuel tank). The temperature of the liquefied gas fuel at this time is raised by the heat of the engine, and from here, the liquefied gas fuel is cooled by the fuel cooling device and returned to the fuel dunk.

  By the way, the vehicle is provided with an air conditioner (air conditioner) that generates air conditioned air for cooling the air by the refrigerant circulating in the refrigeration cycle and air-conditioning the interior of the vehicle. The refrigerant of this type is used to cool the liquefied gas fuel by supplying the refrigerant of the air conditioner to the heat exchanger through which the liquefied gas fuel passes (for example, Patent Document 1, Patent Document 2, (See Patent Document 3).

  On the other hand, when using the refrigerant of an air conditioner, in order to prevent that a refrigerant | coolant and liquefied gas fuel are mixed, high airtightness is requested | required of a heat exchanger. From here, it has been proposed to cool the fuel using a fuel coolant cooled by a refrigerant (for example, Patent Document 4).

  However, airtightness in the heat exchanger is required not only for the refrigerant but also for the piping of the liquefied gas fuel. In particular, in a heat exchanger in which a large number of thin tubes through which liquefied gas fuel passes are arranged in a thick tube through which a refrigerant is passed, the hermeticity is likely to be lowered at the penetration portion of the thin tube. The refrigerant may be mixed.

In addition, when the liquefied gas fuel is cooled using the refrigerant of the air conditioner, the compressor of the air conditioner needs to be driven even if the occupant has stopped the air conditioner operation of the air conditioner. Is required to operate.
JP-A-8-42412 Japanese Patent No. 3282391 JP 2005-273577 A Japanese Patent Laid-Open No. 7-4326

The present invention has been made in view of the above fact, prevented when the liquefied gas fuel for cooling using a refrigerant of the air conditioner, that the liquefied gas fuel and coolant will be mixed, liquefied gas fuels It is an object of the present invention to provide a fuel cooling device that enables efficient cooling.

In order to achieve the above object, a fuel cooling device of the present invention stores liquefied gas fuel injected at a predetermined injection pressure higher than a saturated vapor pressure in a liquid phase state, and supplies the stored liquefied gas fuel to an engine. Heat exchange is performed between the fuel tank to be supplied, the fuel pipe through which the liquefied gas fuel returned from the engine to the fuel tank passes, and the liquefied gas fuel provided in the fuel pipe and passing through the refrigerant and the fuel pipe. A heat exchanger that cools the liquefied gas fuel, and a thick tube through which the refrigerant passes, a narrow tube that is provided in the thick tube and through which the liquefied gas fuel passes, and in the thick tube A refrigerant chamber through which the thin tube is inserted and through which the refrigerant passes, and a fuel passage chamber which is provided at both ends of the thick tube and each of the thin tubes is opened to allow the liquefied gas fuel to pass therethrough. And before A space between the refrigerant chamber and the fuel passage chamber is formed between the refrigerant chamber and the fuel passage chamber by closing the space between the refrigerant chamber and the fuel passage chamber with a second partition wall. and penetrated the tubules hollow portion which is passed through, and including a heat exchanger, and performs the air conditioning operation of the passenger compartment by the refrigerating cycle in which the refrigerant is circulated, the heat exchanger is the coolant in the refrigeration cycle An air conditioner that cools the liquefied gas fuel passing through the heat exchanger by being circulated to the refrigerant chamber of the cooler, a pressure detecting means for detecting the pressure of the liquefied gas fuel in the fuel tank, and a temperature outside the vehicle. An outside air temperature detecting means for detecting a certain outside air temperature, and the pressure detected by the pressure detecting means when the engine is driven and the air conditioning operation of the air conditioner is stopped is detected by the outside air temperature detecting means. Detected Cooling control means for operating the air conditioner to circulate the refrigerant to the heat exchanger to cool the liquefied gas fuel when a cooling start pressure set according to the outside air temperature is exceeded. It is .

According to the present invention , when returning the liquefied gas fuel from the engine to the fuel tank, if the cooling of the liquefied gas fuel is stopped by stopping the operation of the air conditioner, the temperature of the liquefied gas fuel in the fuel tank rises. Along with this, the pressure in the fuel tank (saturated vapor pressure) also increases.
The liquefied gas fuel injected into the fuel tank has a saturated vapor pressure corresponding to the outside air temperature, and the liquefied gas fuel is injected into the fuel tank at an injection pressure set for the saturated vapor pressure. The
Here, the cooling control means determines whether or not the liquefied gas fuel in the fuel tank needs to be cooled based on the outside air temperature and the pressure in the fuel tank, and determines that cooling is necessary from the pressure in the fuel tank. When this is done, the liquefied gas fuel in the fuel tank is cooled by operating the air conditioner and cooling the liquefied gas fuel passing through the heat exchanger.
As a result, the inside of the fuel tank can be maintained at a pressure at which liquefied gas fuel can be injected without unnecessarily operating the air conditioner.
In the heat exchanger, a large number of thin tubes are arranged in the refrigerant chamber in the thick tube, and the liquefied gas fuel supplied from one fuel passage chamber to the narrow tube and flowing to the other fuel passage chamber is cooled by the refrigerant passing through the refrigerant chamber. Is done. A hollow portion is provided between the refrigerant chamber and the fuel passage chamber, and the space between the hollow portion and the refrigerant chamber and the fuel passage chamber is closed by the first and second partition walls.

  As a result, if the airtightness around the narrow tube penetrating the second partition is lowered, the liquefied gas fuel leaks from the fuel passage chamber into the hollow portion, but the hollow portion and the refrigerant chamber are in the first partition. Therefore, the leaked liquefied gas fuel is not mixed with the refrigerant.

Heat exchanger to be applied to the present invention comprises a closed covering section member you form the coolant chamber into the thick tube was closed by the first partition wall is provided at both ends of the thick tube, one end An intermediate member formed in a cylindrical shape closed by the second partition wall and attached to cover the first partition wall of the closing member to form the hollow portion inside the cylindrical shape ; and said second attached so as to cover the partition wall to form the fuel passage chamber, can be pre Ki燃 charge pipe forms comprise a connecting member connected.

The fuel cooling device according to claim 3, provided than before Symbol heat exchanger to the fuel pipe of the engine side, the fuel pipe when the flow rate of the liquefied gas fuel passing through the fuel in the pipe is increased occluded by including a blocking means, the blocking the flow of the liquefied gas fuel to the heat exchanger.

According to the present invention, the heat exchanger, for example, decreases the air-tightness between the fuel passage chamber and the hollow portion, when the liquefied gas fuel leaked into the hollow portion, the liquefied gas fuel in the fuel pipe Increase instantaneously. A shut-off means is provided on the engine side of the fuel pipe, and the shut-off means shuts off the liquefied gas fuel when the flow rate of the liquefied gas fuel increases.

  Thereby, for example, from the change in the flow rate of the liquefied gas fuel, the heat exchanger can detect the decrease in the airtightness of the liquefied gas fuel at an early stage, and the liquefied gas fuel is mixed with the refrigerant due to the decrease in the airtightness. Can be reliably prevented.

The invention according to claim 4, a temperature detection means for detecting the temperature of the liquefied gas fuel in the fuel tank is detected by the temperature and the pressure detecting means of the liquefied gas fuel to the detection of said temperature detecting means sets the saturated vapor pressure of the liquefied gas fuel with respect to the temperature of the liquefied gas fuel in the fuel tank based on the pressure of the liquefied gas fuel, the liquefied gas fuel with respect to the ambient temperature based on the set saturation vapor pressure including a setting unit, a setting the cooling initiation pressure.

The invention of claim 5, wherein the cooling starting pressure is higher than the saturated vapor pressure of the same temperature, and is set lower than the injection pressure of the liquefied gas fuel to the fuel tank.

The liquefied gas fuel has a different saturated vapor pressure with respect to temperature depending on the composition. Accordingly, in the invention of claim 4, the saturated vapor pressure with respect to the temperature of the liquefied gas fuel is set based on the pressure of the fuel tank detected by the pressure detecting means and the temperature detected by the temperature detecting means, and the set saturated steam is set. The cooling start pressure is set based on the pressure .

At this time, in the invention of claim 5, the cooling start pressure is set higher than the saturated vapor pressure at the same temperature and lower than the injection pressure.

  By operating the air conditioner in which the air conditioning operation is stopped based on the cooling start pressure thus set, the air conditioner can be efficiently operated to cool the liquefied gas fuel.

In the present invention, the air conditioner may be met in to perform the air conditioning operation at a preset operating conditions when the air conditioner is operated by the cooling control means.

Above in this onset bright As described, since the operation of the air conditioner based on the pressure of the liquefied gas fuel in the outside air temperature and the fuel tank, the air conditioning device efficiently actuated, precise cooling of the liquefied gas fuel In addition, the fuel tank can be maintained at a pressure at which the liquefied gas fuel can always be injected.
Further, in the present invention, since the hollow portion is provided between the refrigerant chamber and the fuel passage chamber of the heat exchanger , for example, even if the confidentiality of the fuel passage chamber and the hollow portion is reduced and the liquefied gas fuel leaks. Thus, it is possible to reliably prevent the liquefied gas fuel from being mixed with the refrigerant.

Further, according to the present invention, when the confidentiality of the liquefied gas fuel is reduced in the heat exchanger, the liquefied gas fuel is shut off, so that the state where the confidentiality of the liquefied gas fuel is reduced is continued. It can be surely prevented.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 2 shows a schematic configuration of the fuel cooling device 12 provided in the vehicle 10 applied to the present embodiment. The vehicle 10 includes an engine 14 that uses liquefied gas fuel such as LPG (liquefied petroleum gas) as fuel. Further, the vehicle 10 is provided with a fuel tank 16 serving as a fuel container, and the liquefied gas fuel is stored in the fuel tank 16 in a liquid phase state.

  Between the engine 14 and the fuel tank 16, a delivery pipe 18 that supplies liquefied gas fuel from the fuel tank 16 to the engine 14, and a return pipe 20 that returns the liquefied gas fuel surplus in the engine 14 to the fuel tank 16, Is provided.

  A high-pressure fuel pump 22 is provided in the fuel tank 16, and a delivery pipe 18 is connected to the discharge side of the fuel pump 22 via an excess flow prevention valve (FFV) 24 and an extraction valve 26. ing. The delivery pipe 18 is provided with a fuel filter 28, an emergency shut-off valve 30, and an electromagnetic valve 32.

  The liquefied gas fuel in the fuel tank 16 is supplied to the engine 14 in a liquid phase state by operating the pump 22. At this time, the foreign matter contained in the liquid phase liquefied gas fuel is removed by the fuel filter 28. Further, the overflow prevention valve 24 forcibly cuts off the pumping of the liquefied gas fuel when the flow rate of the liquefied gas fuel suddenly increases, thereby preventing the leakage of the liquefied gas fuel from the delivery pipe 18. The emergency shut-off valve 30 shuts off the liquefied gas fuel pumping in an emergency, and the electromagnetic valve 32 shuts off the liquefied gas fuel pumping at the time of fuel cut or the like.

  The engine 14 is provided with a fuel rail 34 and an injector 36 for each cylinder. The delivery pipe 18 is connected to a fuel rail 34, and liquid phase liquefied gas fuel is supplied from the fuel rail 34 to the injector 36 of each cylinder. The injector 36 injects liquefied gas fuel supplied from the fuel rail 34 into the intake manifold 38.

  Air that has passed through an air filter (not shown) is sucked into the intake manifold 38 from the intake pipe 40 via the surge tank 42. The amount of suction air at this time is controlled by the throttle valve 44.

  In the intake manifold 38, a combustible air-fuel mixture is generated by the sucked air and the liquefied gas fuel injected into the air, and this combustible air-fuel mixture is sucked into the combustion chamber of each cylinder of the engine 14. Further, the exhaust gas generated when the combustible air-fuel mixture is burned in the engine 14 is purified and silenced from the exhaust manifold 46 via the exhaust pipe 48 and discharged outside the vehicle.

  As described above, the vehicle 10 uses the fuel injection type engine 14 that injects the liquefied gas fuel in the liquid phase state into the intake manifold 38. The vehicle 10 is not limited to this, and an arbitrary fuel injection method such as a method of injecting liquid phase liquefied gas fuel into the fuel chamber of each cylinder can be applied.

  On the other hand, one end of the return pipe 20 is connected to the fuel rail 34, and surplus liquefied gas fuel is sent from the fuel rail 34 to the return pipe 20. The return pipe 20 is provided with a check valve 50 at the other end, and communicates with the fuel tank 16 via the check valve 50.

  Further, the return pipe 20 is provided with a pressure regulator 52 and a fuel pressure switching valve 54, and further, a pressure regulator 58 is provided in a bypass pipe 56 connected so as to bypass the fuel pressure switching valve 54.

  Normally, the fuel pressure switching valve 54 is open, and in this state, the liquefied gas fuel maintained at a constant pressure by passing through the pressure regulator 52 is recovered in the fuel tank 16. Further, when the fuel pressure switching valve 54 is closed, the pressure is increased by passing through the pressure regulator 52 and the pressure regulator 58 of the bypass pipe 56, compared to when the liquefied gas fuel passes only through the pressure regulator 52. To the fuel tank 16.

  On the other hand, the vehicle 10 is provided with an engine ECU 60 (not shown in FIG. 2, see FIG. 1) that controls the driving of the engine 14. The intake pipe 40 is provided with an aero flow meter 62, and the engine ECU 60 detects the intake air amount by the aero flow meter 62.

  As shown in FIG. 2, the fuel tank 16 is provided with a pressure sensor 64 for detecting the pressure of the liquefied gas fuel in the fuel tank 16 and a temperature sensor 66 for detecting the temperature of the liquefied gas fuel in the fuel tank 16. The pressure sensor 64 and the temperature sensor 66 are connected to the engine ECU 60.

In addition, the vehicle 10 includes an intake air temperature sensor that detects the temperature of air drawn into the engine 14, an accelerator position sensor that detects the amount of depression of the accelerator pedal, and a pressure sensor that detects the pressure of liquefied gas fuel in the fuel rail 34. And a temperature sensor that detects the temperature of the liquefied gas fuel, a throttle position sensor that detects the opening of the throttle valve 44, a water temperature sensor that detects the temperature (water temperature) of the cooling water of the engine 14, and the rotational speed of the engine 14 (the crankshaft) Various sensors (not shown) such as a rotational speed sensor for detecting the rotational speed), an O ₂ sensor (lambda sensor) for detecting the oxygen concentration in the exhaust gas, and a vehicle speed sensor for detecting the traveling speed of the vehicle 10 are provided. These sensors are connected to the engine ECU 60.

  The vehicle 10 is provided with various actuators (not shown) such as an ignition coil connected to an ignition plug provided for each cylinder, a throttle motor for operating the throttle valve 44, and the like. Each injector 36 is connected to the engine ECU 60.

  The engine ECU 60 controls the operation of the actuator based on the detection states of various sensors, thereby performing liquefied gas fuel injection control, ignition timing control, etc., and supplying the liquefied gas fuel to the engine 14. Is driven in an optimal state.

  Further, the fuel pump 22, the emergency shutoff valve 30, the electromagnetic valve 32, the fuel pressure switching valve 54, and the like shown in FIG. 2 are connected to the engine ECU 60 (not shown), and the engine ECU 60 controls these operations. Thus, the supply control of the liquefied gas fuel is performed. Note that various types of control by the engine ECU 60 can be conventionally known control, and detailed description thereof is omitted here.

  On the other hand, as shown in FIG. 1, the vehicle 10 is provided with an air conditioner (hereinafter, referred to as an air conditioner 68) that air-conditions the passenger compartment. The air conditioner 68 includes a compressor 70, a condenser 72, a receiver 74, an expansion valve 76, and an evaporator 78, which form a refrigeration cycle in which refrigerant is circulated.

  In this refrigeration cycle, the refrigerant is compressed by driving the compressor 70, and the high-temperature and high-pressure refrigerant is sent to the condenser 72. The refrigerant sent to the condenser 72 is cooled and liquefied by heat exchange with the outside air passing through the condenser 72. The liquefied refrigerant exchanges heat with the air passing through the evaporator by the evaporator 78. At this time, the liquefied refrigerant is vaporized by the evaporator, whereby the air passing through the evaporator 78 is cooled and dehumidified.

  The receiver 74 performs gas-liquid separation of the refrigerant and sends the liquefied refrigerant to the expansion valve 76. The expansion valve 76 abruptly depressurizes the liquefied refrigerant and supplies it to the evaporator 78 as a mist, thereby improving the efficiency of refrigerant vaporization in the evaporator 78.

  The air conditioner 68 includes an air conditioner unit 80, and a blower fan 82 is provided in the air conditioner unit 80 as an air blowing unit together with an evaporator 78. The air conditioner unit 80 is formed with a flow path of air to be conditioned air, and the blower motor 84 is operated to rotate the blower fan 82 so that air to be conditioned air is sucked into the air conditioner unit 80. And sent to the evaporator 78.

  In the air conditioner 68, an internal air circulation mode for introducing air inside the vehicle interior and an external air introduction mode for introducing air outside the vehicle are set as the air introduction modes, and the internal air or the external air is switched by a switching damper (not shown). Is sucked into the air conditioner unit 80.

  In the air conditioner unit 80, when the compressor 70 is driven to rotate, the introduced air passes through the evaporator 78, whereby cooling and dehumidification are performed.

  In addition, the air conditioner unit 80 is provided with a heater core through which coolant of the engine 14 (engine coolant) is circulated and an air mix damper that controls the amount of air passing through the heater core, and each of them is directed in a predetermined direction. The air conditioner 68 generates a conditioned air having a desired temperature and blows the generated conditioned air from the air outlet to air-condition the passenger compartment.

  The air conditioner 68 is provided with an air conditioner ECU 86. The air conditioner ECU 86 controls the drive of the compressor 70, the blower motor 84, and the like to generate conditioned air having a desired temperature and air volume. For example, the air conditioner ECU 86 controls the rotational voltage of the blower fan 82 by controlling the drive voltage of the blower motor 84 so as to obtain a predetermined air volume. At this time, the minimum voltage and the maximum voltage of the drive voltage of the blower motor 84 are set in the air conditioner ECU 86, and the air conditioner ECU 86 drives the blower motor 84 in this voltage range. Thus, the conditioned air is generated in the range of the air volume (minimum air volume) corresponding to the minimum voltage to the air volume (maximum air volume) corresponding to the maximum voltage.

  For example, when an operating condition such as a set temperature is set by operating a switch on an operation panel (not shown) and an air conditioning operation is instructed, the air conditioner ECU 86 detects an environmental condition such as a room temperature, an outside air temperature, a solar radiation amount, Based on the operating conditions, a target blowing temperature, which is the temperature of the conditioned air for setting the temperature inside the passenger compartment, is set, and the compressor 70 is driven and the blower motor 84 is rotated so that the conditioned air at the target blowing temperature is obtained. Controls the opening of the air mix damper. A known general configuration can be applied to the operation control of the air conditioner ECU 86.

  By the way, the liquefied gas fuel is pressurized and stored in the fuel tank 16 as a liquid phase. Thereby, the inside of the fuel tank 16 is always the saturated vapor pressure (Vapor Pressure) of the liquefied gas fuel. The saturated vapor pressure varies depending on the component (composition) of the liquefied gas fuel, and changes depending on the temperature of the liquefied gas fuel.

  FIG. 3 shows an outline of the saturated vapor pressure of LPG (liquefied petroleum gas) as an example of liquefied gas fuel. As shown in FIG. 3, the saturated vapor pressure of the liquefied gas fuel increases as the temperature increases.

LPG is mainly composed of propane and butane, and the saturated vapor pressure varies depending on the ratio of propane and butane. That is, the saturation vapor pressure varies depending on the composition of LPG. In FIG. 3, propane 100% is LPG ₁₀ , butane 100% and propane 0% is LPG _0, and the ratio of propane to butane is 9: 1, 8: 2,... 2: 8, 1: 9. LPG ₉ , LPG ₈ ,... LPG ₂ , LPG ₁ respectively.

  Here, the temperature of the liquefied gas fuel in the fuel tank 16 is detected by the temperature sensor 66, and the pressure of the liquefied gas fuel in the fuel tank 16 is detected by the pressure sensor 64, so that saturation with respect to the temperature shown in FIG. From the vapor pressure map, the composition of the liquefied gas fuel (LPG) can be determined. At the same time, a saturated vapor pressure with respect to the temperature of the liquefied gas fuel in the fuel tank 16 can be obtained.

  If the pressure (injection pressure) of the liquefied gas fuel injected into the fuel tank 16 is lower than the pressure in the fuel tank 16, the fuel tank 16 cannot be filled with the liquefied gas fuel. From this point, when filling the liquefied gas fuel into the fuel tank 16, the liquefied gas fuel is injected at a pressure higher than the saturated vapor pressure (hereinafter referred to as injection pressure Pin). Generally, the injection pressure Pin is a pressure that is higher by about 0.4 (MPa) to 0.6 (MPa) than the saturated vapor pressure.

  On the other hand, the temperature of the liquefied gas fuel returned from the engine 14 to the fuel tank 16 via the return pipe 20 is increased by the heat of the engine 14, and when the liquefied gas fuel having the increased temperature is recovered in the fuel tank 16, The temperature of the liquefied gas fuel in the fuel tank 16 increases and the saturated vapor pressure also increases.

  Here, the vehicle 10 is provided with a fuel cooling device 12. By using the fuel cooling device 12, the liquefied gas fuel returned to the fuel tank 16 and the liquefied gas fuel in the fuel tank 16 are cooled. Is possible.

  As shown in FIGS. 1 and 2, the fuel cooling device 12 includes a heat exchanger 100. As shown in FIG. 2, the heat exchanger 100 is provided between the fuel pressure switching valve 54 (bypass pipe 56) and the check valve 50 of the fuel tank 16, and is operated by the pressure regulator 52 or the pressure regulators 52, 54. The liquefied gas fuel having a predetermined pressure is passed. In the following description, the return pipe 20 on the inlet side (engine 14 side, fuel supply fuel pipe of the heat exchanger 100) to the heat exchanger 100 is referred to as the return pipe 20A, and the return pipe 20 on the outlet side (fuel tank 16 side) is referred to. It is assumed that the return pipe 20B.

  As shown in FIG. 1, a refrigerant pipe 88A branched from between the receiver 74 and the expansion valve 76 and a refrigerant pipe 88B branched from between the compressor 70 and the evaporator 78 are connected to the heat exchanger 100. Yes. Further, a throttle valve 102 is provided in the refrigerant pipe 88A.

  Thereby, the refrigerant in the liquid phase is supplied from the receiver 74 to the heat exchanger 100, and this refrigerant passes through the heat exchanger 100 and is returned to the compressor 70. At this time, the throttle valve 102 limits the amount of refrigerant supplied to the heat exchanger 100.

  In the fuel cooling device 12, when the liquefied gas fuel and the refrigerant are supplied to the heat exchanger 100, heat exchange is performed between the refrigerant and the liquefied gas fuel, and the liquefied gas fuel is cooled. That is, in the fuel cooling device 12, the liquid refrigerant supplied to the heat exchanger 100 is vaporized in the heat exchanger 100, thereby cooling the liquefied gas fuel passing through the heat exchanger 100. Thereby, in the vehicle 10, the liquefied gas fuel heated by the heat of the engine 14 is cooled by the fuel cooling device 12 and returned to the fuel tank 16.

  4 to 8 show a schematic configuration of the heat exchanger 100 applied to the present embodiment. The heat exchanger 100 includes a cylindrical thick tube 104 as a first tube, and a cylindrical thin tube 106 (not shown in FIG. 4) having a smaller diameter than the thick tube 104 as a second tube. Yes. As shown in FIGS. 5 to 8, in the heat exchanger 100, a plurality of thin tubes 106 are arranged in the thick tube 104. In the following, description will be made using the cylindrical thick tube 104 and the thin tube 106, but the shape is not limited to the cylindrical shape.

  As shown in FIGS. 4 to 7, the thick tube 104 is provided with closing members 108 at both ends. In the closing member 108, for example, a disc-shaped flat portion 110 serving as a first partition and a cylindrical portion 112 protruding from the outer peripheral portion of the flat portion 110 are integrally formed. Thereby, as shown in FIGS. 5 to 7, the closing member 108 has a substantially U-shaped cross section. The closing member 108 has the end portion of the thick tube 104 fitted in the tubular portion 112, and the outer periphery of the thick tube 104 and the tubular portion 112 are brazed over the entire periphery and are firmly fixed. Thus, a refrigerant chamber 104A through which the refrigerant passes is formed in the thick tube 104.

  As shown in FIG. 6, a through hole 110 </ b> A that matches the outer diameter of the thin tube 106 is formed in the flat portion 110 of the closing member 108, and the thin tube 106 disposed in the thick tube 104 is formed in the through hole 110 </ b> A. It is inserted. The narrow tube 106 has a tip projecting from the thick tube 104 (see FIGS. 5 and 7), and the outer periphery of the thin tube 106 and the peripheral portion of the through hole 110A are brazed over the entire periphery of the thin tube 106. It is sealed by being firmly fixed. Thereby, in the heat exchanger 100, the inside of the thick tube 104 is sealed, and the thin tube 106 is held in the refrigerant chamber 104A in the sealed thick tube 104.

  As shown in FIGS. 4 and 5, the thick pipe 104 has a refrigerant pipe 88A connected to one end in the axial direction, a refrigerant pipe 88B connected to the other end, and each of the refrigerant pipes 88A and 88B, An opening is made in the refrigerant chamber 104A in the thick tube 104 (see FIGS. 8A and 8B). Note that the refrigerant pipes 88A and 88B are sealed by brazing the outer periphery of the refrigerant pipes 88A and 88B to the thick pipe 104 over the entire periphery, thereby being tightly fixed. 8A shows a schematic cross section of the thick pipe 104 on the refrigerant pipe 88B side, and FIG. 8B shows a schematic cross section of the thick pipe 104 on the refrigerant pipe 88A side.

  Thereby, the refrigerant sent from the refrigerant pipe 88 </ b> A is filled in the refrigerant chamber 104 </ b> A in the thick pipe 104. The refrigerant charged in the refrigerant chamber 104A is discharged from the refrigerant pipe 88B by the newly sent refrigerant (the refrigerant passes through the refrigerant chamber 104A).

  In the heat exchanger 100, the liquefied gas fuel passes through the narrow tube 106 as will be described later. At this time, the refrigerant absorbs the heat of the liquefied gas fuel and changes from the liquid phase state to the gas phase state. As a result, the liquefied gas fuel is cooled.

  As shown in FIGS. 4 and 5, the heat exchanger 100 is fixed to a predetermined position of the vehicle 10 by brackets 114 and 116. At this time, as shown in FIGS. 8A and 8B, in the heat exchanger 100, the connection position of the refrigerant pipes 88A and 88B is slightly different from the lower end of the thick tube 104. It is designed to be on the upper side. 4 to 8, the upper side when the heat exchanger 100 is attached to the vehicle 10 is indicated by an arrow Up.

  The refrigerant cools the liquefied gas fuel by absorbing heat from the liquefied gas fuel when changing from the liquid phase state to the gas phase state. For this reason, when the refrigerant in the thick tube 104 is in a gas phase, the cooling capacity of the heat exchanger 100 is lowered. Further, the liquid-phase refrigerant is accumulated on the bottom side (lower side) of the thick tube 104, and the liquid-phase refrigerant remains, so that the cooling capacity can be prevented from being lowered. If it is provided at the lower end of the thick pipe 104, the liquid phase refrigerant is preferentially discharged and the vapor phase refrigerant is likely to remain in the thick pipe 104.

  From here, as shown in FIG. 8A, in the heat exchanger 100, the refrigerant pipe 88 </ b> B has an opening above the lower end of the thick pipe 104 when attached to the vehicle 10. A pipe 88 </ b> B is attached to the thick pipe 104. Accordingly, in the heat exchanger 100, the liquid phase refrigerant can remain at the bottom of the thick tube 104, and the exhaust efficiency of the refrigerant in the gas phase state is increased, so that the high cooling efficiency. Is maintained.

  On the other hand, as shown in FIGS. 4 and 5, the heat exchanger 100 has a connection member 118 to which a return pipe 20 </ b> A is connected on one end side and a connection in which a return pipe 20 </ b> B is connected to the other end side. A member 120 is attached. In the heat exchanger 100, an intermediate member 122 is provided between the closing member 108 at the end of the thick tube 104 and the connection members 118 and 120. Note that the basic structures of the connecting members 118 and 120 are substantially the same, and the common configuration of the connecting members 118 and 120 will be described using the connecting member 118 as an example.

  As shown in FIGS. 5 to 7, the intermediate member 122 is integrally formed with a disk-shaped flat surface portion 124 serving as a second partition and a cylindrical body portion 126 protruding from the periphery of the flat surface portion 124. Thus, the cross section is substantially U-shaped. Further, the intermediate member 122 is formed with a stepped portion 128 having an enlarged opening diameter at the opening side end portion of the cylindrical body portion 126.

  In the intermediate member 122, the closing member 108 is inserted and fixed in the stepped portion 128 from the flat portion 110 side, whereby the intermediate member 122 is attached to the thick tube 104. It is preferable that the closing member 108 and the intermediate member 122 are attached firmly by brazing or the like over the entire circumference of the closing member 108 fitted in the intermediate member 122. Any fixing method can be applied as long as fixing is possible.

  Here, since the intermediate member 122 is provided with the stepped portion 128 at the end of the cylindrical body portion 126, when the intermediate member 122 is attached to the closing member 108, the inside member, that is, the flat surface portion 110 of the closing member 108 and the intermediate member. A hollow portion 130 is formed between the flat portion 124 of 122 and the inside of the hollow portion 130 is normally at atmospheric pressure.

  The connection member 118 (120) is formed in a substantially cylindrical shape with one end opened, and the intermediate member 122 is inserted into the flat portion 124 side from the opening side of the connection member 118. At this time, voids are formed in the connection members 118 and 120. The intermediate member 122 is brazed to the connection member 118 over the entire periphery and is firmly fixed.

  The return pipe 20A connected to the connection member 118 is opened in the connection member 118, and the liquefied gas fuel is sent from the return pipe 20A into the gap (hereinafter referred to as the introduction portion 132) of the connection member 118. The return pipe 20B connected to the connection member 120 is opened in the connection member 120, and the liquefied gas fuel is sent out from the gap (hereinafter referred to as a delivery part 134) of the connection member 120 to the return pipe 20B. It is.

  As shown in FIG. 6, a through-hole 124 </ b> A corresponding to the outer diameter of the thin tube 106 is formed in the flat surface portion 124 of the intermediate member 122, and the distal end portion of the thin tube 106 protruding from the closing member 108 is It is inserted into the through hole 124A and opened in the introduction part 132 (the delivery part 134). The narrow tube 106 and the return pipes 20A and 20B are sealed by being brazed and fixed all around.

  As a result, the liquefied gas fuel sent from the return pipe 20A into the introduction section 132 is diverted to each of the narrow pipes 106, and the liquefied gas fuel that has passed through the narrow pipe 106 is collected in the delivery section 134 and sent out from the return pipe 20B. .

  Here, in the heat exchanger 100, a hollow portion 130 is provided between the inside of the refrigerant chamber 104A of the thick tube 104 serving as a refrigerant passage and between the introduction portion 132 and the delivery portion 134 serving as a passage for liquefied gas fuel, and a thick portion 130 is provided. Inside the tube 104, the space between the introduction part 132 and the delivery part 134 and the hollow part 130 is sealed. Thereby, for example, the flat surface portion 110 (between the inside of the thick tube 104 and the hollow portion 130) through which the thin tube 106 is inserted, or the flat surface portion 124 (the hollow portion 130, the introduction portion 132, and the delivery portion) of the intermediate member 122. 134), the refrigerant and the liquefied gas fuel are prevented from being mixed.

  Further, in the heat exchanger 100, the inside of the hollow portion 130 is at atmospheric pressure, the airtightness between the hollow portion 130 and the introduction portion 132 or the delivery portion 134 is reduced, and the liquefied gas fuel is introduced into the introduction portion 132 or the delivery portion. When flowing from the portion 134 into the hollow portion 130, the flow rate of the liquefied gas fuel passing through the return pipe 20A increases instantaneously. At this time, if the inside of the hollow portion 130 is sealed, it is possible to prevent the confidentiality of the flow path of the liquefied gas fuel from being greatly reduced.

  As shown in FIGS. 1 and 2, the fuel cooling device 12 is provided with an overflow prevention valve 90 as a shut-off means on the engine 14 side of the heat exchanger 100. As shown in FIG. 2, the overflow prevention valve 90 is provided in the return pipe 20 (20 </ b> A) between the fuel pressure switching valve 54 (bypass pipe 56) and the heat exchanger 100. Further, when the flow rate of the liquefied gas fuel passing through the return pipe 20A suddenly increases, the overflow prevention valve 90 operates by mechanically detecting the increase in the flow rate and shuts off the flow path of the liquefied gas fuel. To do.

  As a result, in the fuel cooling device 12, when the confidentiality of the liquefied gas fuel is reduced in the heat exchanger 100, the overflow prevention valve 90 operates to shut off the liquefied gas fuel.

  On the other hand, the engine ECU 60 serves as a cooling control means for the fuel cooling device 12 and controls the pressure of the liquefied gas fuel in the fuel tank 16 by cooling the liquefied gas fuel returned from the engine 14 to the fuel tank 16. Do.

  The heat exchanger 100 can cool the liquefied gas fuel in a state where the compressor 70 of the air conditioner 68 is driven. In the fuel cooling device 12, when the driving of the compressor 70 is stopped, the liquefied gas fuel is cooled. Cooling is also stopped.

  As shown in FIG. 1, an air conditioner ECU 86 is connected to the engine ECU 60, whereby the engine ECU 60 determines whether or not the air conditioner 68 is in operation, that is, the compressor 70 is driven and the heat exchanger 100. It is possible to confirm whether or not the liquefied gas fuel is being cooled.

  Further, the engine ECU 60 requests the air conditioner ECU 86 to drive the compressor 70 when cooling the liquefied gas fuel while the compressor 70 is stopped.

  When the compressor 70 is in a stopped state and the driving request for the compressor 70 is input from the engine ECU 60, the air conditioner ECU 86 sets the compressor 70 to a predetermined capacity (the number of revolutions, for example, a rotation at which a minimum cooling capacity or a minimum cooling capacity is obtained. Drive).

  In addition, when the air conditioner ECU 86 drives the compressor 70 while the air conditioner 68 is stopped, the air conditioner ECU 86 rotates the blower motor 84 so that the minimum air volume is obtained. As a result, the refrigerant supplied to the evaporator 78 is prevented from frosting on the evaporator 78.

  Here, when the compressor 70 is driven, the refrigerant is circulated through the heat exchanger 100, and the liquefied gas fuel passing through the heat exchanger 100 is cooled by the refrigerant. Further, the liquefied gas fuel cooled by the heat exchanger 100 is recovered in the fuel tank 16, whereby the temperature of the liquefied gas fuel in the fuel tank 16 is reduced.

  When the compressor 70 is driven based on a request from the engine ECU 60, the air-conditioning air outlet may be set as a register outlet, and the set temperature when the air conditioner 68 is stopped or a preset reference temperature. The target blowing temperature may be set so as to obtain the conditioned air based on the above, and the opening control of the air mix damper may be performed so as to obtain the conditioned air having the set target blowing temperature.

  On the other hand, the engine ECU 60 sets the pressure for starting cooling (cooling start pressure, which is the cooling operation pressure Pa in the present embodiment) from the saturated vapor pressure with respect to the temperature of the liquefied gas fuel stored in the fuel tank 16. Then, it is determined whether or not the pressure P of the liquefied gas fuel in the fuel tank 16 has reached the cooling operation pressure Pa. Further, the engine ECU 60 cools the liquefied gas fuel using the heat exchanger 100 when the pressure P in the fuel tank 16 exceeds the cooling operation pressure Pa.

  As described above, the saturated vapor pressure of liquefied gas fuel (LPG) varies depending on the components. From here, the engine ECU 60 stores a map of the saturated vapor pressure with respect to the temperature shown in FIG. 3, and the engine ECU 60 uses the temperature sensor 66 to liquefy gas fuel in the fuel tank 16 at a preset timing. The pressure in the fuel tank 16 (pressure of the liquefied gas fuel in the vapor phase (Vapor)) is detected using the temperature and pressure sensor 64.

  Further, the engine ECU 60 sets a saturated vapor pressure Pv with respect to the temperature of the liquefied gas fuel in the fuel tank 16 based on the measured temperature and pressure. If the temperature of the liquefied gas fuel in the fuel tank 16 is the same as the outside air temperature, the saturated vapor pressure Pv becomes the saturated vapor pressure with respect to the outside air temperature.

  Based on the saturated vapor pressure Pv, the engine ECU 60 sets a pressure (cooling operation pressure Pa) for cooling the liquefied gas fuel in the fuel tank 16 using the refrigerant of the heat exchanger 100 and the air conditioner 68. As shown in FIG. 9, the cooling operation pressure Pa is set higher than the saturated vapor pressure Pv at the same temperature and lower than the injection pressure Pin of the liquefied gas fuel when the fuel is supplied to the fuel tank 16.

  That is, the engine ECU 60 sets the cooling operation pressure Pv to a pressure (Pv) lower than the injection pressure Pin when the fuel tank 16 is filled with liquefied gas fuel (Pin> Pv) and higher than the saturated vapor pressure Pv by a predetermined value α. <Pa <Pin, Pa = Pv + α). When the injection pressure Pin = Pv + 0.4 to 0.6 (MPa), the cooling operation pressure Pa = Pv + 0.3 (MPa) can be set.

  On the other hand, as shown in FIG. 1, the vehicle 10 is provided with an outside air temperature sensor 92 that detects the outside air temperature. The outside air temperature sensor 92 is connected to the engine ECU 60, and the engine ECU 60 can detect the outside air temperature by the outside air temperature sensor 92.

  The engine ECU 60 determines whether or not the liquefied gas fuel in the fuel tank 16 needs to be cooled based on the outside air temperature Ta detected by the outside air temperature sensor 92 and the cooling operation pressure Pv, and is detected by the pressure sensor 64. When the pressure P of the liquefied gas fuel in the fuel tank 16 exceeds the cooling operation pressure Pa with respect to the outside air temperature Ta, it is determined that the liquefied gas fuel needs to be cooled, and the air conditioner ECU 86 is requested to drive the compressor 70. The liquefied gas fuel in the fuel tank 16 is cooled to reduce the pressure P of the liquefied gas fuel.

  In the vehicle 10 configured as described above, the liquefied gas fuel injected at an injection pressure higher than the saturated vapor pressure is stored in the fuel tank 16 in a liquid phase state. When the vehicle travels, the liquefied gas fuel in the fuel tank 16 is supplied to the fuel rail 34 via the delivery pipe 18 by the drive of the fuel pump 22, and is injected from the injector 36 into the intake manifold 38.

  The intake manifold 38 is supplied with an amount of air corresponding to the opening of the throttle valve 44, and the liquefied gas fuel is mixed with this air so as to have a predetermined air-fuel ratio and sucked into each cylinder of the engine 14. Is done. The vehicle 10 is driven by the driving force of the engine 14 generated by the combustion of the air-fuel mixture in the cylinder.

  On the other hand, in the vehicle 10, the excess liquefied gas fuel in the fuel rail 34 is collected in the fuel tank 16 via the return pipe 20. At this time, the liquefied gas fuel is recovered to the fuel tank 16 when the pressure regulator 52 provided in the return pipe 20 or the pressure regulators 52 and 58 is brought to a predetermined pressure or higher.

  The vehicle 10 is provided with a fuel cooling device 12. In the fuel cooling device 12, when the refrigerant of the air conditioner 68 is supplied to the heat exchanger 100, heat exchange is performed between the refrigerant and the liquefied gas fuel, and the liquefied gas fuel is cooled. In the fuel cooling device 12, the liquefied gas fuel recovered in the fuel tank 16 is cooled to suppress an increase in the pressure of the liquefied gas fuel in the fuel tank 16, and liquefied gas fuel is supplied (filled) to the fuel tank 16. It is made possible.

  By the way, in the fuel cooling device 12, the liquefied gas fuel is cooled using the refrigerant compressed by the compressor 70, and the refrigerant and the liquefied gas fuel are passed through the heat exchanger 100 and pass through the heat exchanger 100. The obtained refrigerant is compressed by the compressor 70. For this reason, it is necessary to prevent the liquefied gas fuel from being mixed with the refrigerant.

  Here, in the heat exchanger 100 of the fuel cooling device 12, the hollow portion 130 is provided between the inside of the thick tube 104 through which the refrigerant passes and the introduction portion 132 and the delivery portion 134 in which the narrow tube 106 through which the liquefied gas fuel passes is opened. Provided. Thereby, for example, even if the sealing performance between the thick tube 104 and the hollow portion 130 is reduced, or the sealing performance between the hollow portion 130 and the introduction portion 132 or the delivery portion 134 is reduced, the liquefied gas fuel and the refrigerant And will not be mixed. That is, even if the sealing performance of either the hollow section 130 and the thick tube 104 or between the introduction section 132 and the delivery section 134 is reduced, the liquefied gas is used as the refrigerant as long as the other sealing performance is secured. There is no fuel mixing.

  Further, in the heat exchanger 100, the inside of the hollow portion 130 is at atmospheric pressure whose pressure is lower than that of the introduction portion 132 and the delivery portion 134. For this reason, if the sealing performance between the hollow portion 130 and the introduction portion 132 or the delivery portion 134 is lowered, the liquefied gas fuel flows into the hollow portion 130, and the flow rate of the liquefied gas fuel in the return pipe 20A is instantaneous. Increase.

  Here, the fuel cooling device 12 is provided with an overflow prevention valve 90 in the return pipe 20A on the upstream side of the heat exchanger 100. When the flow rate of the liquefied gas fuel in the return pipe 20A increases, The prevention valve 90 is activated to close the return pipe 20A. Thereby, the liquefied gas fuel to the heat exchanger 100 is shut off, and the heat exchanger 100 can reliably prevent a decrease in confidentiality of the liquefied gas fuel flow path.

  On the other hand, in the fuel cooling device 12, when the air conditioning operation of the air conditioner 68 is stopped, the cooling of the liquefied gas fuel is stopped. Thereby, when the temperature of the liquefied gas fuel in the fuel tank 16 rises, it may be difficult to replenish (inject) the liquefied gas fuel into the fuel tank 16.

  Here, in the fuel cooling device 12, the air conditioner 68 is efficiently operated to suppress an increase in pressure in the fuel tank 16, and the fuel tank 16 can always be filled with liquefied gas fuel.

  Here, the cooling process of the liquefied gas fuel by the engine ECU 60 provided as the control means of the fuel cooling device 12 will be described with reference to FIGS. 9 to 11.

  FIG. 10 shows an outline of the setting process. This flowchart is set in advance, for example, when an ignition switch (not shown) is turned on when the vehicle 10 starts traveling, at a predetermined time interval during vehicle traveling, or after filling the fuel tank 16 with liquefied gas fuel. It is executed at the timing.

  In the first step 200 of this flowchart, the temperature sensor 66 detects the temperature T of the liquefied gas fuel in the fuel tank 16 and the pressure sensor 64 detects the pressure P of the liquefied gas fuel (step 202).

  In the next step 204, a saturated vapor pressure Pv with respect to the temperature of the liquefied gas fuel stored in the fuel tank 16 is set from the detected temperature T and pressure P. The saturated vapor pressure Pv is set, for example, by storing a map of the saturated vapor pressure with respect to the temperature corresponding to the composition (component) of the liquefied gas fuel, and from the pressure detected by the pressure sensor 64 and the temperature detected by the temperature sensor 66. A method such as selecting a corresponding saturated vapor pressure Pv can be applied.

  When the saturated vapor pressure Pv is set, in the next step 206, the cooling operation pressure Pa is set based on the saturated vapor pressure Pv. Further, the engine ECU 60 stores the saturated vapor pressure Pv and the cooling operation pressure Pa. In step 208, the saturation vapor pressure Pv and the cooling operation pressure Pa are updated based on the setting.

  Thereby, the saturated vapor pressure Pv with respect to the temperature (external temperature Ta) shown in FIG. 9 and the cooling operation pressure Pa with respect to the saturated vapor pressure are obtained.

  On the other hand, FIG. 11 shows an outline of the pressure control process of the liquefied gas fuel in the fuel tank 16. This flowchart is executed when an ignition switch (not shown) of the vehicle 10 is turned on, and ends when the ignition switch is turned off.

  In this flowchart, it is confirmed whether or not the air conditioning operation of the air conditioner 68 is stopped in the first step 210, that is, whether or not the driving of the compressor 70 is stopped.

  Here, when the air conditioning operation of the air conditioner 68 is stopped, an affirmative determination is made at step 210 and the routine proceeds to step 212. In step 212, the outside air temperature sensor 92 detects the temperature outside the vehicle (outside air temperature Ta), and in step 214, the cooling operation pressure Pa corresponding to the outside air temperature Ta is read.

  In step 216, the pressure P in the fuel tank 16 is detected by the pressure sensor 64.

  Thereafter, in step 218, it is determined whether or not the pressure P exceeds the cooling operation pressure Pa by comparing the pressure P with the cooling operation pressure Pa.

  Here, when the temperature of the liquefied gas fuel in the fuel tank 16 increases, the saturated vapor pressure also increases, and the pressure P detected by the pressure sensor 64 also increases. Accordingly, when the cooling operation pressure Pa with respect to the outside air temperature Ta is exceeded (P ≧ Pa), an affirmative determination is made in step 218 and the process proceeds to step 220. In step 220, the engine ECU 60 requests the air conditioner ECU 86 to operate the air conditioner 68 (drive the compressor 70).

  When the air conditioning operation is stopped and the operation request is input from the engine ECU 60, the air conditioner ECU 86 drives the compressor 70 to start circulation of the refrigerant.

  Accordingly, the refrigerant compressed by the compressor 70 is circulated to the heat exchanger 100, and heat exchange is performed between the refrigerant and the liquefied gas fuel, whereby the liquefied gas fuel is cooled. Further, the liquefied gas fuel cooled by the heat exchanger 100 is recovered in the fuel tank 16, whereby the temperature in the fuel tank 16 is lowered and the pressure in the fuel tank 16 is lowered.

That is, the temperature of the liquefied gas fuel charged into the fuel tank 16 from the outside (outside the vehicle) can be regarded as the outside air temperature Ta, although it depends on the storage environment. From here, as shown in FIG. 9, the outside air temperature Ta is, for example, when a temperature T _1, the pressure of the liquefied gas fuel which is filled in the fuel tank 16 at that time (injection pressure Pin), the pressure P ₁ It becomes.

At this time, the temperature of the liquefied gas fuel in the fuel tank 16 is, for example, when being raised to a temperature T _2, the pressure P detected by the pressure sensor 64 is higher pressure P ₂ becomes than the pressure P _1, a fuel tank It becomes difficult to fill 16 with liquefied gas fuel.

At this time, in the fuel cooling device 12, the liquefied gas fuel is cooled by forcibly operating the air conditioner 68, and the cooled liquefied gas fuel is recovered into the fuel tank 16. Is going down. As a result, the liquefied gas fuel in the fuel tank 16 falls to a temperature T ₃ or lower, and the pressure P ₃ detected by the pressure sensor 64 is the pressure P ₃ that is the cooling operating pressure Pa when the outside air temperature Ta is the temperature T _1. It is as follows (P <Pa).

  In the flowchart shown in FIG. 11, when the pressure P detected by the pressure sensor 64 is equal to or lower than the cooling operation pressure Pv corresponding to the outside air temperature Ta (P <Pv), a negative determination is made in step 220 and the process proceeds to step 222. To do.

  In this step 222, it is confirmed whether or not the air conditioner 68 is requested to operate the air conditioner 68 (forced operation). When the forced operation of the air conditioner 68 is requested, an affirmative determination is made in step 222 and the routine proceeds to step 224. Then, the operation request for the air conditioner 68 is canceled. In step 226, it is confirmed whether or not the air conditioning operation of the air conditioner 68 has been started. When the occupant operates the air conditioner 68 and the air conditioning operation is started, an affirmative determination is made in step 226, and this processing is performed. Is temporarily terminated.

  Thus, in the fuel cooling device 12, when the pressure P in the fuel tank 16 drops to a pressure at which the liquefied gas fuel can be charged, the air conditioner 68 is returned to the stopped state without continuing the operation. As a result, the air conditioner 68 is operated efficiently and maintained in a state where the fuel tank 16 can be filled with the liquefied gas fuel.

  In addition, this Embodiment demonstrated above does not limit the structure of this invention. For example, in the present embodiment, when the liquefied gas fuel leaks into the hollow portion 130 in the heat exchanger 100 in the heat exchanger 100, the flow rate of the liquefied gas fuel is increased as a blocking means for blocking the liquefied gas fuel. Although the overflow prevention valve 90 that mechanically operates when it occurs is not limited to this, the shut-off means is not limited to this. For example, a flow rate sensor or a pressure sensor is used, and the airtightness of the liquefied gas fuel is reduced. Pressure due to a decrease in the confidentiality of the flow path of the liquefied gas fuel in the heat exchanger 100, such as a configuration in which the liquefied gas fuel is shut off by detecting a change in flow rate or a change in pressure when the solenoid valve is operated Any configuration can be applied as long as the liquefied gas fuel is cut off based on the change or the flow rate change.

  Moreover, the heat exchanger 100 applied to this Embodiment attaches the obstruction | occlusion member 108, the intermediate member 122, and the connection members 118 and 120 to the thick pipe 104, 104A of refrigerant | coolants chambers, the hollow part 130, the introduction part 132, and delivery Although the part 134 is formed, the configuration of the heat exchanger to which the present invention is applied is not limited to this. For example, in the heat exchanger 100, the hollow portion 130 is sealed, but it is sufficient that at least the space between the hollow portion 130 and the refrigerant chamber 104A and the space between the hollow portion 130 and the introduction portion 132 and the delivery portion 134 are sealed. For example, the hollow part 130 may be configured to be open to the atmosphere.

  In addition, as the heat exchanger, an arbitrary configuration is applied such that first and second partition walls are formed at both ends of the thick tube 104, and a refrigerant chamber, a hollow portion, and a fuel passage chamber are formed in the thick tube. be able to.

  Furthermore, the fuel cooling device of the present invention is not limited to the fuel cooling device 12, but can be applied to a vehicle having any configuration that returns the liquefied gas fuel that has become surplus in the engine 14 to the fuel tank.

It is a schematic block diagram of a fuel cooling device and an air conditioner. It is a schematic block diagram of fuel supply. It is a diagram which shows the outline of the saturated vapor pressure with respect to the temperature according to the composition of liquefied gas fuel. It is a schematic perspective view which shows the external appearance of the heat exchanger which concerns on this Embodiment. It is a schematic block diagram of a heat exchanger. FIG. 3 is an exploded perspective view of one end of the heat exchanger. It is the schematic sectional drawing which cut | disconnected the edge part of the heat exchanger along the axial direction. (A) And (B) is the schematic cross section which cut | disconnected the edge part of the heat exchanger in the direction orthogonal to an axial direction, (A) has shown the discharge side of the refrigerant | coolant, (B) has shown the injection side of the refrigerant | coolant. . It is a diagram which shows an example of the saturated vapor pressure with respect to temperature, a cooling operation pressure, and injection pressure. It is a flowchart which shows an example of the setting of a saturated vapor pressure and a cooling operation pressure. It is a flowchart which shows the outline of the cooling process of liquefied gas fuel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Vehicle 12 Fuel cooling device 14 Engine 60 Engine ECU (cooling control means)
64 Pressure sensor (pressure detection means)
66 Temperature sensor (temperature detection means)
68 Air conditioner
70 Compressor 82 Blower Fan 86 Air Conditioner ECU
90 Overflow prevention valve (blocking means)
92 Outside air temperature sensor (outside air temperature detecting means)
DESCRIPTION OF SYMBOLS 100 Heat exchanger 104 Thick pipe | tube 104A Refrigerant chamber 106 Narrow pipe | tube 108 Closure member 110 Planar part (1st partition)
118, 120 connecting member 122 intermediate member 124 plane part (second partition)
130 hollow part 132 introduction part (fuel passage chamber)
134 Delivery section (fuel passage chamber)

Claims (6)

A fuel tank in which liquefied gas fuel injected at a predetermined injection pressure higher than the saturated vapor pressure is stored in a liquid phase state, and the stored liquefied gas fuel is supplied to the engine;
Fuel piping through which the liquefied gas fuel returned from the engine to the fuel tank passes;
A heat exchanger that is provided in the fuel pipe and that cools the liquefied gas fuel by performing heat exchange between the refrigerant and the liquefied gas fuel passing through the fuel pipe, and is a thick pipe through which the refrigerant passes. A thin tube provided in the thick tube and through which the liquefied gas fuel passes, a refrigerant chamber formed in the thick tube, through which the thin tube is inserted and through which the refrigerant passes, and Each of the thin tubes provided at both ends is opened, and a space between the fuel passage chamber through which the liquefied gas fuel passes and the refrigerant chamber is closed by a first partition wall, and a space between the fuel passage chamber is provided. is closed by the second partition is formed between the coolant chamber and the fuel passage chamber, and a hollow portion in which the capillary is through the first and second partitions is passed, the including heat exchanger,
Air-conditioning operation of the passenger compartment is performed by a refrigeration cycle in which the refrigerant is circulated, and the liquefied gas fuel passing through the heat exchanger is caused by circulating the refrigerant in the refrigeration cycle to the refrigerant chamber of the heat exchanger. A cooling air conditioner;
Pressure detecting means for detecting the pressure of the liquefied gas fuel in the fuel tank;
An outside air temperature detecting means for detecting an outside air temperature that is outside the vehicle;
When the engine is driven and the air-conditioning operation of the air-conditioning apparatus is stopped, the pressure detected by the pressure detection means is a cooling set according to the outside air temperature detected by the outside air temperature detection means Cooling control means for operating the air conditioner to circulate the refrigerant to the heat exchanger to cool the liquefied gas fuel when a starting pressure is exceeded;
A fuel cooling device . The heat exchanger is
And a closed covering section member you form the coolant chamber into the thick tube was closed by the provided at both ends of the thick tube first partition wall,
An intermediate member having one end formed in a cylindrical shape closed by the second partition wall and attached to cover the first partition wall of the closing member to form the hollow portion inside the cylindrical shape ;
And wherein the intermediate member second attached so as to cover the partition wall to form the fuel passage chamber, before the connection Ki燃 charges pipe is connected member,
The fuel cooling device according to claim 1 , comprising: Provided from the previous SL heat exchanger to the fuel pipe of the engine side, the to the heat exchanger by closing the fuel pipe when the flow rate of the liquefied gas fuel passing through the fuel in the pipe is increased Blocking means for blocking the inflow of liquefied gas fuel;
The fuel cooling device according to claim 1 , comprising: Temperature detecting means for detecting the temperature of the liquefied gas fuel in the fuel tank;
Based on the temperature of the liquefied gas fuel detected by the temperature detecting means and the pressure of the liquefied gas fuel detected by the pressure detecting means, the saturated vapor pressure of the liquefied gas fuel with respect to the temperature of the liquefied gas fuel in the fuel tank is determined. setting while a setting device for setting the cooling starting pressure of the liquefied gas fuel with respect to the ambient temperature based on the set saturated vapor pressure,
The fuel cooling device according to any one of claims 3 including claim 1. The fuel cooling device according to claim 4 , wherein the cooling start pressure is set higher than the saturated vapor pressure at the same temperature and lower than the injection pressure of the liquefied gas fuel into the fuel tank . The fuel cooling device according to any one of claims 1 to 5 for performing air conditioning operation in the operating condition in which the air conditioner is set in advance when the air conditioner is operated by the cooling control means.

Images