Fuel supply device

Abstract

To simplify a configuration for cooling liquefied gas fuel and effectively use cold of the liquefied gas fuel in a device for supplying the liquefied gas fuel to an internal combustion engine.SOLUTION: Liquefied gas fuel is injected from a fuel injection valve 36 into an intake pipe 28 of an internal combustion engine 12. By using vaporization latent heat of the injected fuel, cold transfer fluid flowing in a cooling flow passage 40 is cooled. The cooled cold transfer fluid is sent to a cooler 44. In the cooler 44, by using the cooled cooling transfer fluid, liquefied gas fuel to be sent toward the fuel injection valve 36 in a fuel supply pipe 35 is cooled.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a fuel supply device that supplies liquefied gas fuel to an internal combustion engine. [Background technology]

[0002] In an internal combustion engine that supplies liquefied gas fuel in a liquid state through a fuel injection valve, if the temperature of the fuel rises and a portion of the fuel vaporizes, causing the fuel to enter a gas-liquid mixed state, the amount of fuel supplied to the cylinders of the internal combustion engine may become unstable.Patent Document 1 listed below discloses a liquefied gas fuel supply device (2) that cools the liquefied gas fuel supplied to a fuel injection valve (injector 8) in a fuel cooling device (12) using a refrigerant from an air conditioner (13) mounted on the vehicle.

[0003] The following Patent Document 2 discloses a liquefied gas fuel supply device (1) that supplies liquefied gas fuel to a fuel injection valve (injector 6) by a high-pressure pump (4). The fuel is sent from a fuel tank (2) to the high-pressure pump (4) via a cooler (8), and is cooled in the cooler (8) by utilizing the latent heat of vaporization of fuel supplied via a system separate from the fuel supplied to the internal combustion engine. The liquefied gas fuel supply device (1) includes a fuel carburetor (13), a compressor (14), a condenser (15), and a radiator (12) for vaporizing, compressing, condensing, and radiating heat from the fuel supplied via the separate system.

[0004] The component names and symbols in parentheses above are those used in Patent Documents 1 and 2, and are not related to the component names and symbols used in the description of the embodiments of the present application. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-89697 [Patent Document 2] Japanese Patent Application Laid-Open No. 2010-174692 Summary of the Invention [Problem to be solved by the invention]

[0006] There is a demand for a simpler device for cooling liquefied gas fuel before it is sent to a fuel injection valve, and there is also a demand for a reduction in the energy consumed to cool the liquefied gas fuel.

[0007] The present invention aims to at least one of simplifying the configuration of a device for cooling liquefied gas fuel and reducing the energy required for cooling in a fuel supply device that supplies liquefied gas fuel to an internal combustion engine. [Means for solving the problem]

[0008] The fuel supply device of the present invention includes a fuel injection valve that injects liquefied gas fuel toward the inner wall of an intake pipe of an internal combustion engine, a cooling flow path through which a cold heat transfer fluid flows, the cooling flow path being provided in a fuel adhesion portion of the intake pipe where the injected liquefied gas fuel adheres, or adjacent to the fuel adhesion portion, and the cold heat transfer fluid is cooled by the latent heat of vaporization of the injected liquefied gas fuel, and a cooler that is provided in a fuel supply pipe that supplies liquefied gas fuel to the fuel injection valve, and that cools the liquefied gas fuel supplied to the fuel injection valve by the cold heat transfer fluid cooled in the cooling flow path.

[0009] By utilizing the latent heat of vaporization of the liquefied gas fuel that is vaporized for combustion in the internal combustion engine, it is no longer necessary to provide a system for vaporizing fuel or fluid separate from the fuel sent to the internal combustion engine, which simplifies the device configuration. In addition, by utilizing the cold heat of the liquefied gas fuel, which has not been utilized until now, it is possible to reduce the energy required to cool the liquefied gas fuel.

[0010] The fuel supply device may include a circulation passage for circulating a cold transfer fluid through the cooling passage and the cooler.

[0011] In the above fuel supply device, the cold heat transfer fluid may be liquefied gas fuel, and the cooler may be a confluence pipe that confluences the liquefied gas fuel cooled in the cooling flow path with the liquefied gas fuel that is supplied to the fuel injection valve.

[0012] In the above fuel supply device, the fuel-attached portion of the intake pipe may be made of a material with higher thermal conductivity than the other portions of the intake pipe, thereby increasing the efficiency of cooling of the refrigeration transfer fluid by the latent heat of vaporization of the fuel.

[0013] In the above fuel supply device, the intake pipe may include a heat insulating portion sandwiched between an upstream portion including the fuel deposit portion and a downstream portion on the cylinder chamber side of the internal combustion engine, thereby suppressing a temperature rise in the fuel deposit portion due to heat transfer from the cylinder chamber side.

[0014] The fuel supply device may further include a temperature sensor that acquires the temperature of the liquefied gas fuel supplied to the fuel injection valve, and a control unit that controls the fuel injection valve to inject the liquefied gas fuel while an intake valve of the internal combustion engine is closed when the temperature of the liquefied gas fuel acquired by the temperature sensor is equal to or higher than a predetermined temperature. By injecting the liquefied gas fuel when the intake valve is closed and the airflow in the intake pipe is weak, more of the liquefied gas fuel can be used to cool the refrigeration transfer fluid.

[0015] In the above fuel supply device, the liquefied gas fuel may be ammonia. [Effects of the Invention]

[0016] By utilizing the liquefied gas fuel injected into the intake pipe and the intake pipe, the configuration for cooling the liquefied gas fuel can be simplified.By utilizing the cold heat of the liquefied gas fuel, the energy required for cooling the liquefied gas fuel can be reduced. [Brief explanation of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram schematically illustrating a configuration example of a fuel supply device. [Figure 2]FIG. 1 is a phase diagram of ammonia. [Figure 3] FIG. 10 is a diagram schematically illustrating another configuration example of the fuel supply device. [Figure 4] FIG. 10 is a diagram schematically illustrating yet another configuration example of the fuel supply device. [Figure 5] FIG. 10 is a diagram schematically illustrating yet another configuration example of the fuel supply device. [Figure 6] FIG. 10 is a diagram schematically illustrating yet another configuration example of the fuel supply device. DETAILED DESCRIPTION OF THE INVENTION

[0018] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Fig. 1 schematically shows a fuel supply device 14 that supplies a liquefied gas fuel, for example, ammonia, stored in a fuel tank 10 to an internal combustion engine 12. The liquefied gas fuel (hereinafter referred to as fuel) is stored in a liquid state in the fuel tank 10. The internal combustion engine 12 is a reciprocating piston engine, and may be a single-cylinder engine or a multi-cylinder engine. In Fig. 1, the internal combustion engine 12 is represented by one cylinder.

[0019] The internal combustion engine 12 includes a piston 18, a cylinder block 20, and a cylinder head 22 that define a cylinder chamber 16. The cylinder head 22 has an intake port 24 that opens into the cylinder chamber 16, and is further equipped with an intake valve 26 that opens and closes the opening of the intake port 24 at a predetermined timing. An intake pipe 28 is connected to the intake port 24. The cylinder head 22 has an exhaust port 30 that opens into the cylinder chamber 16, and is further equipped with an exhaust valve 32 that opens and closes the opening of the exhaust port 30 at a predetermined timing. An exhaust pipe 34 is connected to the exhaust port 30.

[0020] The fuel supply device 14 includes a fuel injection valve 36 that injects fuel into the intake pipe 28 and a fuel supply pipe 35 that delivers fuel from the fuel tank 10 to the fuel injection valve 36. The fuel injection valve 36 injects fuel toward the inner wall surface of the intake pipe 28 on the side opposite to the side on which the fuel injection valve 36 is disposed, and at least a portion of the fuel adheres to the inner wall surface of the intake pipe 28 in a liquid state. The portion of the intake pipe 28 where the fuel adheres is referred to as a fuel adhesion portion 38. A cooling channel 40 is provided in the fuel adhesion portion 38. The cooling channel 40 may be formed within the pipe wall of the intake pipe 28 at the fuel adhesion portion 38. Alternatively, the cooling channel 40 may be provided outside the intake pipe 28 at the fuel adhesion portion 38, adjacent to the fuel adhesion portion 38 so as to be thermally conductive. The latent heat of vaporization of the fuel adhered to the fuel adhesion portion 38 cools the refrigeration transfer fluid flowing through the cooling channel 40. The cooling flow passage 40 may be formed as a wide flow passage to increase the contact area with the fuel-attached portion 38, or may be formed in a serpentine shape. The cooling flow passage 40 is part of a circulation-shaped cold transfer circulation flow passage 42 through which a cold transfer fluid flows. The cold transfer fluid may be water or an antifreeze liquid used as a coolant for an internal combustion engine.

[0021] Downstream of the cooling passage 40, the cold heat transfer circulation passage 42 passes through a cooler 44 that cools the fuel sent to the fuel injection valve 36. In the cooler 44, the cold heat transfer fluid cooled in the cooling passage 40 exchanges heat with the fuel, thereby cooling the fuel. The cold heat transfer circulation passage 42 is equipped with a circulation pump 46 that circulates the cold heat transfer fluid. The circulating cold heat transfer fluid transfers cold energy, which is the energy that the injected fuel uses to remove heat from its surroundings and cool it, from the cooling passage 40 to the cooler 44, and the cold energy cools the fuel flowing through the fuel supply pipe 35 in the cooler 44.

[0022] The fuel-attached portion 38 of the intake pipe 28 may be formed of a material with a higher thermal conductivity than the other portions. For example, in the intake pipe 28 made of stainless steel, the fuel-attached portion 38 may be made of an aluminum alloy. Furthermore, a heat insulating member 48 may be disposed between the upstream portion of the intake pipe 28, including the fuel-attached portion 38, and the downstream portion, which is closer to the cylinder chamber 16. The heat insulating member 48 is formed of a material with a lower thermal conductivity than the other portions of the intake pipe 28. For example, if the intake pipe 28 is made of an aluminum alloy, the heat insulating member 48 may be made of resin. By disposing the heat insulating member 48, the transfer of heat generated in the cylinder chamber 16 to the fuel-attached portion 38 is suppressed. This suppresses a temperature rise in the fuel-attached portion 38, thereby improving the cooling efficiency of the refrigeration transfer fluid using the latent heat of vaporization of the fuel.

[0023] The fuel supply device 14 includes a control unit 50 that controls the operation of the fuel injection valve 36 and the circulation pump 46. The control unit 50 performs control based on the temperature of the fuel immediately before it is injected from the fuel injection valve 36. A fuel temperature sensor 52 is provided downstream of the cooler 44 in the fuel supply pipe 35 to detect the temperature of the fuel. The control unit 50 may include one or more processing devices that operate according to a predetermined program.

[0024] The operation of the fuel supply device 14 will be described using an example in which ammonia is used as the liquefied gas fuel. FIG. 2 is a phase diagram of ammonia. In FIG. 2, ammonia is liquid in the region to the left of the saturated vapor pressure curve V, and gas in the region to the right. The inside of the fuel tank 10 is at the saturated vapor pressure of ammonia. The following description will be given using an example in which the ammonia in the fuel tank 10 is at 30°C.

[0025] The fuel (ammonia) in the fuel tank 10 is in a saturated vapor pressure state at 30°C, as indicated by point A in Figure 2. If the fuel is not cooled during delivery from the fuel tank 10 to the fuel injection valve 36, a portion of the fuel will vaporize due to heat transfer from the surroundings and heat radiation from the internal combustion engine 12, and the fuel will be delivered to the fuel injection valve 36 in a gas-liquid mixture state. In this gas-liquid mixture state, it is difficult to accurately control the injection amount from the fuel injection valve 36. To suppress fuel vaporization, the fuel delivered to the fuel injection valve 36 is cooled. Specifically, when the internal combustion engine 12 starts operating, the control unit 50 controls the operation of the circulation pump 46 to circulate the cold transfer fluid. The fuel injected from the fuel injection valve 36 adheres, in a liquid state, to the inner wall surface of the fuel adhesion portion 38 of the intake pipe 28 and vaporizes there. The fuel adhesion portion 38 is cooled by the latent heat of vaporization of the fuel, and the cold transfer fluid flowing through the cooling channel 40 is also cooled. The cooled refrigeration transfer fluid is sent to a cooler 44 to cool the fuel flowing through the fuel supply pipe 35 .

[0026] When the temperature of the fuel immediately before being injected from the fuel injection valve 36 is equal to or higher than a predetermined temperature (hereinafter referred to as the injection timing switching temperature), the timing of fuel injection may be set to within the period during which the intake valve 26 is closed. The injection timing switching temperature may be, for example, 15°C lower than the saturation temperature (point B in FIG. 2). The control unit 50 acquires the fuel temperature using a fuel temperature sensor 52. Furthermore, the operation of the intake valve 26 can be acquired from a control device of the internal combustion engine 12. Specifically, the operation of the intake valve 26 can be acquired based on one or both of the rotation angle of a crankshaft (not shown), which is the output shaft, and the rotation angle of a camshaft (not shown), which operates the intake valve 26. While the intake valve 26 is closed, the airflow velocity in the intake pipe 28 is low, and the injected fuel is not carried away by the airflow, so more of it adheres to the fuel adhesion portion 38. Therefore, more of the fuel vaporizes in the fuel adhesion portion 38, thereby further lowering the temperature of the refrigeration transfer fluid. On the other hand, if the temperature of the fuel immediately before injection is lower than the injection timing switching temperature (temperature at point B), there is no need to cool the fuel so much, and the fuel injection timing may be set to when the intake valve 26 is open in order to vaporize the fuel before it adheres to the intake pipe wall. In this way, the control unit 50 switches the fuel injection timing based on the fuel temperature. Also, if the temperature of the fuel immediately before injection is lower than the injection timing switching temperature (temperature at point B), the control unit 50 may stop the circulation pump 46. This can reduce the energy consumption required to operate the circulation pump 46. When the temperature rises again, the operation of the circulation pump 46 is resumed.

[0027] FIG. 3 shows another example of the configuration of the fuel supply device. The fuel supply device 60 shown in FIG. 3 differs from the aforementioned fuel supply device 14 in that a cooling device 62 is provided in the cold heat transfer circulation flow path 42. The same components as those in the fuel supply device 14 are designated by the same reference numerals and will not be described again. The cooling device 62 includes a refrigeration cycle and cools the cold heat transfer fluid using a refrigerant circulating through the refrigeration cycle. If the internal combustion engine 12 is used to drive a vehicle, the cooling device 62 may be an air conditioning device for cooling the passenger compartment of the vehicle. When the temperature of the fuel immediately before injection is relatively high, specifically, when the temperature is equal to or higher than point C, which is higher than point B in FIG. 2, the cooling device 62 performs additional cooling of the cold heat transfer fluid. The temperature of point C is referred to as the additional cooling temperature. The additional cooling temperature may be, for example, 5°C lower than the saturation temperature. When the temperature detected by the fuel temperature sensor 52 is higher than the additional cooling temperature, the control unit 50 activates the cooling device 62 to cool the cold heat transfer fluid using the refrigerant in the cooling device 62. Furthermore, when the cooling device 62 utilizes an on-board air conditioner, the control unit 50 guides the refrigerant of the on-board air conditioner to a heat exchanger provided in the cold heat transfer circulation flow path 42. Since the cold heat transfer fluid is cooled by the latent heat of vaporization of the injected fuel, the energy required to operate the cooling device 62 is reduced accordingly.

[0028] Fig. 4 shows another example of the configuration of the fuel supply device. The fuel supply device 70 shown in Fig. 4 changes the timing of fuel injection based on the temperature of the cold transfer fluid, not the temperature of the fuel immediately before injection. The same components as those in the fuel supply device 14 are given the same reference numerals, and their explanations will be omitted.

[0029] In the fuel supply device 70, fuel injection timing is switched based on the temperature difference between the refrigeration transfer fluid before and after passing through the cooler 44. A first refrigeration transfer fluid temperature sensor 72 is disposed at the inlet of the cooler 44 in the refrigeration transfer circulation flow path 42, and a second refrigeration transfer fluid temperature sensor 74 is disposed at the outlet. When the temperature difference between the first and second refrigeration transfer fluid temperature sensors 72, 74 reaches a predetermined value or greater, the control unit 50 controls the fuel injection valve 36 to inject fuel while the intake valve 26 is closed. When the temperature difference between the refrigeration transfer fluid before and after passing through the cooler 44 is large, it is estimated that the temperature of the fuel entering the cooler 44 is high. Therefore, similar to the fuel supply device 14 described above, fuel is injected while the intake valve 26 is closed to further cool the refrigeration transfer fluid in the cooling flow path 40. Furthermore, when the temperature difference of the refrigeration transfer fluid before and after the cooler 44 is less than the predetermined value, the control unit 50 controls the fuel injection valve 36 to inject fuel while the intake valve 26 is open, and in addition, the control unit 50 may control the circulation pump 46 to stop.

[0030] Fig. 5 shows yet another example of the configuration of a fuel supply device. The fuel supply device 80 shown in Fig. 5 differs from the above-described fuel supply devices 14, 60, and 70 in that the fuel itself is used as the fluid that transfers the cold energy of the fuel. The same components as those in the fuel supply device 14 are designated by the same reference numerals, and a description thereof will be omitted.

[0031] The fuel supply device 80 includes a fuel reflux flow path 82 that refluxes fuel instead of the cold heat transfer circulation flow path 42. The fuel reflux flow path 82 branches off from a branch point 84 of the fuel supply pipe 35, passes through the cooling flow path 40, and connects to the fuel supply pipe 35 at a junction 86 located upstream of the branch point 84. A reflux pump 88 is provided in the fuel reflux flow path 82, and sends fuel from the branch point 84 to the junction 86. A check valve 89 is provided in the fuel supply pipe 35 upstream of the junction 86. The fuel flowing through the fuel reflux flow path 82 is cooled in the cooling flow path 40 by the latent heat of vaporization of fuel injected from a separate fuel injection valve 36. The cooled fuel then merges with fuel supplied from the fuel tank 10 at the junction 86, lowering the temperature of the fuel flowing downstream of the junction 86. The junction 86 corresponds to a cooler that cools the fuel supplied to the fuel injection valve 36 by the fuel, which is a cold heat transfer fluid cooled in the cooling flow path 40 .

[0032] In the fuel supply device 80, the fuel injection timing may be switched in the same manner as in the above-described fuel supply device 14. When the fuel temperature detected by the fuel temperature sensor 52 is equal to or higher than a predetermined temperature (injection timing switching temperature), the control unit 50 sets the fuel injection timing to within the period when the intake valve 26 is closed. When the fuel temperature is below the injection timing switching temperature, the control unit 50 controls the fuel injection valve 36 to inject fuel while the intake valve 26 is open, and may also control the reflux pump 88 to stop.

[0033] FIG. 6 shows yet another example of the configuration of the fuel supply device. The fuel supply device 90 shown in FIG. 6 has a configuration in which a cooling device 92 is provided in the fuel supply pipe 35 of the fuel supply device 80 described above. The same components as those in the fuel supply device 80 are assigned the same reference numerals, and description thereof will be omitted. The cooling device 92 has the same configuration as the cooling device 62 of the fuel supply device 60 described above. The cooling device 92 cools the fuel using a refrigerant in a refrigeration cycle. When the fuel temperature immediately before injection is relatively high, the control unit 50 controls the cooling device 92 so that cooling is performed by the cooling device 92 in addition to cooling by the latent heat of vaporization of the injected fuel. Because the refrigeration transfer fluid is cooled by the latent heat of vaporization of the injected fuel, the energy required to operate the cooling device 92 is reduced.

[0034] [Note] [1] a fuel injection valve that injects liquefied gas fuel toward an inner wall of an intake pipe of an internal combustion engine; a cooling flow path through which a cold heat transfer fluid flows, the cooling flow path being provided in a fuel attachment portion of the intake pipe where the injected liquefied gas fuel adheres or being provided adjacent to the fuel attachment portion, and the cold heat transfer fluid is cooled by the latent heat of vaporization of the injected liquefied gas fuel; a cooler provided in a fuel supply pipe for supplying liquefied gas fuel to the fuel injection valve, the cooler cooling the liquefied gas fuel supplied to the fuel injection valve by the cold heat transfer fluid cooled in the cooling flow path; A fuel supply device including: [2] The fuel supply device according to the above item [1], further comprising a circulation flow path for circulating the cold heat transfer fluid through the cooling flow path and the cooler. [3] The fuel supply device according to the above item [1], wherein the cold heat transfer fluid is a liquefied gas fuel, and the cooler is a confluence pipe that confluences the liquefied gas fuel cooled in the cooling flow path with the liquefied gas fuel that is supplied to the fuel injection valve. [4] A fuel supply device according to any one of the above items [1] to [3], wherein the fuel adhesion portion of the intake pipe is formed of a material having a higher thermal conductivity than other portions of the intake pipe. [5] The fuel supply device according to any one of the above items [1] to [4], wherein the intake pipe includes a heat-insulating portion sandwiched between an upstream portion including the fuel adhesion portion and a downstream portion on the cylinder chamber side of the internal combustion engine. [6] The fuel supply device according to any one of the above items [1] to [5], a temperature sensor for acquiring a temperature of the liquefied gas fuel supplied to the fuel injection valve; a control unit that controls the fuel injection valve to inject liquefied gas fuel while an intake valve of the internal combustion engine is closed when the temperature of the liquefied gas fuel acquired by the temperature sensor is equal to or higher than a predetermined temperature; A fuel supply device including: [7] The fuel supply device according to any one of the above items [1] to [6], wherein the liquefied gas fuel is ammonia. [Explanation of symbols]

[0035] 10 fuel tank, 12 internal combustion engine, 14, 60, 70, 80, 90 fuel supply device, 16 cylinder chamber, 26 intake valve, 28 intake pipe, 35 fuel supply pipe, 36 fuel injection valve, 38 fuel adhesion portion, 40 cooling flow path, 42 cold heat transfer circulation flow path, 44 cooler, 46 circulation pump, 48 heat insulating member, 50 control unit, 52 fuel temperature sensor, 62, 92 cooling device, 72 first cold heat transfer fluid temperature sensor, 74 second cold heat transfer fluid temperature sensor, 82 fuel return flow path, 88 return pump, 89 check valve.

Claims

1. a fuel injection valve that injects liquefied gas fuel toward an inner wall of an intake pipe of an internal combustion engine; a cooling flow path through which a cold heat transfer fluid flows, the cooling flow path being provided in a fuel attachment portion of the intake pipe where the injected liquefied gas fuel adheres or being provided adjacent to the fuel attachment portion, and the cold heat transfer fluid is cooled by the latent heat of vaporization of the injected liquefied gas fuel; a cooler provided in a fuel supply pipe for supplying liquefied gas fuel to the fuel injection valve, the cooler cooling the liquefied gas fuel supplied to the fuel injection valve by the cold heat transfer fluid cooled in the cooling flow path; A fuel supply device including:

2. 2. The fuel supply system according to claim 1, further comprising a circulation passage for circulating the cold transfer fluid through the cooling passage and the cooler.

3. 2. The fuel supply device according to claim 1, wherein the cold heat transfer fluid is a liquefied gas fuel, and the cooler is a confluence pipe that causes the liquefied gas fuel cooled in the cooling flow path to merge with the liquefied gas fuel that is supplied to the fuel injection valve.

4. 2. The fuel supply device according to claim 1, wherein the fuel deposit portion of the intake pipe is formed of a material having a higher thermal conductivity than other portions of the intake pipe.

5. 2. The fuel supply device according to claim 1, wherein the intake pipe includes a heat-insulating portion sandwiched between an upstream portion including the fuel adhesion portion and a downstream portion on the cylinder chamber side of the internal combustion engine.

6. 6. A fuel supply device according to any one of claims 1 to 5, a temperature sensor for acquiring a temperature of the liquefied gas fuel supplied to the fuel injection valve; a control unit that controls the fuel injection valve to inject liquefied gas fuel while an intake valve of the internal combustion engine is closed when the temperature of the liquefied gas fuel acquired by the temperature sensor is equal to or higher than a predetermined temperature; A fuel supply device including:

7. 2. The fuel supply system of claim 1, wherein the liquefied gas fuel is ammonia.

Images