JP2010144659A - Vaporizing device for liquefied fuel vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vaporizing device for liquefied fuel suppressing power consumption of an engine and increase of a vehicle weight and improving fuel economy of a vehicle with the vaporizing device installed. <P>SOLUTION: The vaporizing device includes a vaporizer 12 vaporizing the liquefied fuel by exchanging heat between the liquefied fuel and heating medium, an exhaust introduction passage 16 branched from an exhaust passage 30 of the engine and introducing a part of exhaust gas of the engine as the heating medium into the vaporizer 12, a valve 17 provided in the exhaust introduction passage 16 and adjusting an amount of the exhaust gas introduced into the vaporizer 12, a temperature sensor 41 detecting temperature of vaporized fuel, and a control unit 20 controlling the temperature of the vaporized fuel by adjusting an opening degree of the valve 17 based on the detected temperature of the vaporized fuel. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vaporizer for a liquefied fuel vehicle that vaporizes liquefied fuel and supplies it to an engine.

  In a liquefied fuel vehicle equipped with an engine that uses liquefied fuel such as liquefied natural gas (LNG) or liquefied petroleum gas (LPG), the liquefied fuel stored in the tank can be vaporized by a vaporizer and supplied to the engine. Has been done. According to this configuration, the internal pressure in the carburetor is increased by the vaporized fuel, and thus the vaporized fuel is pushed out to the engine, so that there is an advantage that a pump for sending out the fuel becomes unnecessary.

In Patent Document 1, engine cooling water is used as a heat source when vaporizing liquefied fuel in a vaporizer. If the engine coolant is guided to the vaporizer and heat exchange is performed between the liquefied fuel and the coolant, the liquefied fuel can be vaporized without using an electric heater or the like.
Japanese Patent Laid-Open No. 2006-17058

  When cooling water is used as a heat source as in the prior art described above, a pump for supplying a sufficient amount of cooling water to the vaporizer is required. However, in this configuration, whether the pump is a pump driven by engine power or an electric pump driven by electric power generated by an alternator, engine power consumption increases and fuel consumption deteriorates.

  Further, the weight of the vehicle increases due to the weight of the pump and the amount of cooling water due to the cooling water piping extending to the vaporizer, which also deteriorates the fuel consumption.

  The present invention has been made in view of such technical problems of the prior art. In the liquefied fuel vaporizer, the power consumption of the engine and the increase in the vehicle weight are suppressed, and the fuel efficiency of the vehicle in which it is mounted is improved. For the purpose.

  According to a first aspect of the present invention, there is provided a vaporizer for a liquefied fuel vehicle that vaporizes liquefied fuel to generate vaporized fuel and supplies the vaporized fuel to an engine, the liquefied fuel being between the liquefied fuel and the heating medium. A vaporizer for vaporizing the liquefied fuel, an exhaust introduction passage for branching from the exhaust passage of the engine, and introducing a part of the exhaust of the engine as the heating medium into the carburetor, Based on the detected temperature of the vaporized fuel, a valve provided in the exhaust gas introduction passage for adjusting the amount of the exhaust gas introduced into the vaporizer, temperature detection means for detecting the temperature of the vaporized fuel, and There is provided a vaporizing device for a liquefied fuel vehicle, comprising temperature control means for adjusting the opening of a valve and performing temperature control of the vaporized fuel.

  According to a second aspect of the present invention, there is provided the vaporizer for a liquefied fuel vehicle according to the first aspect, wherein the outlet side of the exhaust passage in the vaporizer is opened to the atmosphere.

  According to a third aspect of the present invention, in the first or second aspect, the exhaust passage is provided with an exhaust purification catalyst and a muffler in order from the upstream side in the exhaust flow direction. There is provided a liquefied fuel vehicle vaporizer characterized in that the exhaust introduction passage is branched from a position midway between the exhaust purification catalyst and the muffler.

  According to the first aspect, since the exhaust gas can be introduced into the vaporizer using the pressure of the exhaust gas, there is no need for a pump for introducing the heating medium into the vaporizer, and engine cooling water is used. Engine power consumption and vehicle weight can be reduced compared to conventional vaporizers. Further, the medium flowing in the exhaust introduction passage is an exhaust whose weight can be ignored, and the vehicle weight can be reduced as compared with the conventional vaporizer using the cooling water of the engine. Therefore, according to the first aspect, it is possible to suppress the power consumption of the engine and the increase in the vehicle weight, and to improve the fuel consumption of the vehicle on which the engine is mounted.

  According to the second aspect, a sufficient pressure difference is obtained between the exhaust in the exhaust passage and the exhaust in the carburetor, and the exhaust can be smoothly introduced into the carburetor from the exhaust passage.

  According to the third aspect, it is possible to ensure the pressure of the exhaust gas necessary for smoothly introducing the exhaust gas into the carburetor, and environmental problems even if the exhaust gas after passing through the carburetor is released to the atmosphere. Does not occur.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a schematic configuration diagram of a fuel supply system 100 for a liquefied fuel vehicle including a vaporizer according to an embodiment of the present invention.

  The fuel supply system 100 includes a fuel tank 11, a vaporizer 12, a buffer tank 13, a pressure reducing valve 14, an injector 15, an exhaust introduction passage 16, and a control unit 20, and liquefied natural gas (LNG) stored in the fuel tank 11. , Liquefied fuel such as liquefied petroleum gas (LPG) is supplied to the engine.

  The fuel tank 11 is a tank having a heat insulating double structure in which the space between the inner tank 11a and the outer tank 11b is evacuated, and stores the liquefied fuel in a cryogenic state.

  A fuel tank 11 and an exhaust introduction passage 16 are connected to the carburetor 12. From the fuel tank 11, liquefied fuel is introduced into the carburetor 12, and part of the engine exhaust is introduced into the carburetor 12 from the exhaust introduction passage 16. A liquefied fuel flow path 12a and an exhaust flow path 12b are disposed adjacent to each other in the vaporizer 12, and the liquefied fuel and the exhaust perform heat exchange in a non-contact state. The liquefied fuel that has exchanged heat with the exhaust gas is vaporized to become vaporized fuel, and the vaporized fuel is sent to a buffer tank 13 connected downstream of the vaporizer 12 due to an increase in internal pressure in the vaporizer 12.

  The outlet 18 of the exhaust passage 12b in the vaporizer 12 is open to the atmosphere so that the exhaust that has exchanged heat with the liquefied fuel is released to the atmosphere. This is because the pressure P2 of the exhaust gas flowing in the carburetor 12 is lowered by opening to the atmosphere so that it is sufficiently lower than the pressure P1 of the exhaust gas in the exhaust passage 30, and vaporization is performed from the exhaust passage 30 using this pressure difference. This is because the exhaust gas is smoothly introduced into the vessel 12.

  The buffer tank 13 is a tank that temporarily stores vaporized fuel in order to cope with engine load fluctuations. The vaporized fuel stored in the buffer tank 13 is depressurized by the pressure reducing valve 14, then sent to the injector 15, and injected from the injector 15 into the intake passage or cylinder of the engine.

  The exhaust passage 30 of the engine is provided with an exhaust purification catalyst 31 and a muffler 32 in order from the upstream side in the exhaust flow direction. When a plurality of exhaust purification catalysts are provided in the exhaust passage 30, the exhaust purification catalyst 31 is preferably an exhaust purification catalyst provided on the most downstream side. The exhaust introduction passage 16 is branched from a position between the exhaust purification catalyst 31 and the muffler 32 in the middle of the exhaust passage 30. The branching of the exhaust introduction passage 16 from this position can secure the pressure of the exhaust gas necessary for smoothly introducing the exhaust gas into the carburetor 12, and even if the exhaust gas after passing through the carburetor 12 is released to the atmosphere. This is because there is no environmental problem. The exhaust gas introduced from the exhaust gas introduction passage 16 into the carburetor 12 does not pass through the muffler 32, but can be sufficiently silenced by resistance when passing through the carburetor 12.

  A valve 17 capable of electrically adjusting the opening degree is provided in the middle of the exhaust introduction passage 16. The valve 17 may be provided at a connection position between the exhaust passage 30 and the exhaust introduction passage 16 or at a connection position between the carburetor 12 and the exhaust introduction passage 16.

  Between the vaporizer 12 and the buffer tank 13, a temperature sensor 41 for detecting the vaporized fuel temperature T1 is provided. The control unit 20 monitors the vaporized fuel temperature T1 detected by the temperature sensor 41, and adjusts the amount of exhaust gas introduced into the vaporizer 12 by the valve 17 so that the vaporized fuel temperature T1 becomes the target temperature T0. To do.

  As shown in FIG. 2, the control unit 20 includes a CPU 21, a storage device 22 including a RAM / ROM connected to the CPU 21, and an input / output interface 23.

  A signal representing the vaporized fuel temperature T <b> 1 is input from the temperature sensor 41 to the input / output interface 23. The storage device 22 stores a control program for controlling the temperature T1 of the vaporized fuel by adjusting the opening of the valve 17, a parameter (target temperature T0) used in the control program, and the like. The CPU 21 reads out and executes the control program stored in the storage device 22, and determines whether or not it is necessary to adjust the opening degree of the valve 17 based on a signal indicating the vaporized fuel temperature T 1 input to the input / output interface 23. A valve control signal corresponding to this is output from the input / output interface 23 to the valve 17.

  FIG. 3 is a flowchart showing the contents of the control program. This control program is repeatedly executed in the CPU 21 at a predetermined cycle.

  The processing contents of the control unit 20 will be described with reference to this. First, in step S11, the vaporized fuel temperature T1 is read.

  Next, in step S12, it is determined whether the vaporized fuel temperature T1 is lower than the target temperature T0. The target temperature T0 is a vaporized fuel temperature suitable for supplying to the engine.

  As a result of the determination, if the vaporized fuel temperature T1 is lower than the target temperature T0, the process proceeds to step S13, the opening degree of the valve 17 is increased by a predetermined amount to increase the amount of exhaust gas introduced into the vaporizer 12, and the vaporized fuel The temperature T1 is increased. Conversely, if it is higher, the routine proceeds to step S14, where the valve opening is decreased by a predetermined amount to reduce the amount of exhaust gas introduced into the carburetor 12, and the vaporized fuel temperature T1 is lowered.

  Therefore, according to this control, the amount of exhaust gas introduced into the carburetor 12 is adjusted according to the vaporized fuel temperature T1, and thereby the vaporized fuel temperature T1 is controlled to the target temperature T0.

  Then, the effect of the said embodiment is demonstrated.

  In the above embodiment, a part of the engine exhaust is introduced into the vaporizer 12 as a heating medium for the liquefied fuel, and the liquefied fuel is vaporized by performing heat exchange between the liquefied fuel and the exhaust. According to this configuration, since the exhaust gas can be introduced into the vaporizer 12 using the pressure of the exhaust gas, a pump for introducing the heating medium into the vaporizer 12 is not required, and engine cooling water is used. Engine power consumption and vehicle weight can be reduced compared to conventional vaporizers. Further, the medium flowing in the exhaust introduction passage 16 is exhaust whose weight is negligible, and the vehicle weight can be reduced as compared with a conventional vaporizer that uses engine coolant.

  Therefore, in the said embodiment, the increase in the power consumption of an engine and vehicle weight can be suppressed, and the fuel consumption of the vehicle by which this is mounted can be improved.

  Moreover, in the said embodiment, the exit side (exit 18) of the flow path 12b for exhaust in the vaporizer | carburetor 12 was open | released to air | atmosphere. According to this configuration, a sufficient pressure difference is obtained between the exhaust in the exhaust passage 30 and the exhaust in the carburetor 12, and the exhaust can be smoothly introduced into the carburetor 12 from the exhaust passage 30.

  Further, in the above embodiment, the exhaust introduction passage 16 is branched from the position between the exhaust purification catalyst 31 and the muffler 32 in the middle of the exhaust passage 30. According to this configuration, it is possible to ensure the pressure of the exhaust gas necessary for smoothly introducing the exhaust gas into the carburetor 12, and environmental problems even if the exhaust gas that has passed through the carburetor 12 is released to the atmosphere. Does not occur.

  The embodiment of the present invention has been described above, but the above embodiment is merely one example of application of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. is not.

It is a schematic block diagram of the fuel supply system of the liquefied fuel vehicle provided with the vaporization apparatus which concerns on embodiment of this invention. It is an internal block diagram of a control unit. It is the flowchart which showed the content of the control program.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Fuel tank 12 ... Vaporizer 12a ... Flow path for liquefied fuel 12b ... Exhaust flow path 16 ... Exhaust introduction passage 17 ... Valve 18 ... Outlet 20 ... Control unit 30 ... Exhaust passage 31 ... Exhaust purification catalyst 32 ... Muffler 41 ... Temperature sensor 100 ... Fuel supply system

Claims (3)

A vaporizer for a liquefied fuel vehicle, which vaporizes liquefied fuel to generate vaporized fuel and supplies the vaporized fuel to an engine,
A vaporizer for performing heat exchange between the liquefied fuel and a heating medium, and vaporizing the liquefied fuel;
An exhaust introduction passage that branches off from the exhaust passage of the engine and introduces a part of the exhaust of the engine as the heating medium into the carburetor;
A valve provided in the exhaust introduction passage for adjusting the amount of the exhaust introduced into the carburetor;
Temperature detecting means for detecting the temperature of the vaporized fuel;
A temperature control means for adjusting the opening of the valve based on the detected temperature of the vaporized fuel and performing temperature control of the vaporized fuel;
A vaporizer for a liquefied fuel vehicle, comprising:   The carburetor for a liquefied fuel vehicle according to claim 1, wherein the outlet side of the exhaust passage in the carburetor is opened to the atmosphere. In the exhaust passage, an exhaust purification catalyst and a muffler are provided in order from the upstream side in the exhaust flow direction,
The exhaust introduction passage is branched from a position between the exhaust purification catalyst and the muffler in the middle of the exhaust passage.
The vaporizer for a liquefied fuel vehicle according to claim 1 or 2.

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