JP2015224569A - Generating set of automobile and automobile having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively collect the pressure energy of natural gas or hydrogen gas, and to improve fuel economy or the like by utilizing the pressure energy for power generation.SOLUTION: A generating set of an automobile which uses natural gas or hydrogen gas as fuel comprises: a high-pressure tank for filling and storing a compressed gas; a scroll expander which pressure-reduces the compressed gas from the high-pressure tank and expands it; and a generator connected to the scroll expander which is driven by the compressed gas. Power generated by the generator is supplied to a battery of the automobile.

Description

  The present invention relates to a power generation apparatus that recovers the pressure energy of high-pressure gas of a gas fuel vehicle using natural gas as a fuel and a fuel cell vehicle using hydrogen gas as a fuel, and uses the power energy for power generation, and a vehicle equipped with the same.

Compressed natural gas vehicles that use compressed natural gas as engine fuel and fuel cell vehicles equipped with a fuel cell system that generates electricity by electrochemical reaction of hydrogen and oxygen contained in the introduced air have been known. (See Non-Patent Document 1 and Non-Patent Document 2).
These compressed natural gas vehicles (CNG vehicles) and fuel cell vehicles (FCV) can (1) reduce carbon dioxide (CO2) emissions that cause air pollution compared to gasoline and diesel vehicles, contributing to the prevention of global warming. (2) In addition, emissions of air pollutants such as nitrogen oxides (NOx) and particulate matter (PM) such as black smoke are extremely small and can contribute to the improvement of the air environment. (3) Noise can be reduced. As well as comfort, it is also effective for noise control in the entire city. For this reason, in Japan, as a highly practical alternative energy oil vehicle, it is already widely used in trucks, buses, garbage trucks, light freight cars, vans and the like.

  A compressed natural gas automobile fills a gas container (tank) at a high pressure (20 MPa) while keeping natural gas in a gaseous state. In the compressed natural gas supply, the pressure is reduced to a predetermined pressure (about 50 kPa to 325 kPa) from the gas container through the fuel pipe through the pressure reducing valve and supplied to the engine (see FIG. 3). In order to extend the cruising range, fuel cell vehicles are also filled with hydrogen in an ultra-high pressure tank, depressurized to a predetermined pressure via a pressure reducing valve, generated by the fuel cell, and run by rotating an electric motor (electric motor). (See FIG. 4).

Japan Gas Association website http://www.gas.or.jp/ngvj/text/ngv_parts.html Structure of Fuel Cell Vehicle (FCV) http://www.jari.or.jp/portals/0/jhfc/beginner/about_fcv/index.html

  However, the above-described conventional compressed natural gas vehicle cannot supply air through the engine intake system when natural gas is supplied at a pressure higher than atmospheric pressure, and the hydrogen pressure supplied to the fuel cell in a fuel cell vehicle is too high. It discharges without reacting. For this reason, the compressed natural gas and hydrogen are also decompressed to a predetermined low pressure gas by the pressure reducing valve. In other words, since the pressure of the compressed gas stored in the gas container is simply reduced from the high pressure to the low pressure by the pressure reducing valve, the pressure energy is wasted as heat energy and the compressed gas is large. There is an inconvenience that the pressure energy is not effectively used and the use efficiency is not good.

  Therefore, in the present invention, in order to recover the wasteful energy, a scroll expander is installed instead of the pressure reducing valve, and the energy generated by the pressure difference is used in the process of reducing the pressure of the high-pressure compressed gas. It aims at rotating at high speed, driving a generator with the rotational force to supply it to the battery of an automobile, and improving fuel consumption, cruising distance, and the like.

  In order to achieve this object, the present invention provides a power generation apparatus for an automobile that uses a compressed gas of natural gas or hydrogen gas as a fuel, a high-pressure tank that fills and stores the compressed gas, and the compressed gas from the high-pressure tank. A scroll expander that depressurizes and expands, and a generator coupled to the scroll expander driven by the compressed gas, and the power generated by the generator is configured to be supplied to a battery of an automobile. It is characterized by being.

  An automobile according to claim 2 of the present invention includes the automobile power generator according to claim 1.

  In the present invention, in order to recover the wasteful energy, a scroll expander is installed instead of the pressure reducing valve, and in the process of reducing the pressure of the high-pressure compressed gas, the energy generated by the pressure difference is used for high speed rotation. In addition, the generator can be driven by the rotational force and supplied to the battery of the automobile, and the fuel consumption, cruising distance, and the like can be improved.

It is a figure which shows the principal part of the compression natural gas vehicle of the 1st Example which concerns on this invention. It is a figure which shows the principal part of the fuel cell vehicle of the 2nd Example which concerns on this invention. It is a figure which shows the principal part of the compression natural gas vehicle of a prior art example. It is a figure which shows the principal part of the fuel cell vehicle of a prior art example.

  The present invention provides a scroll expander in place of a conventional pressure reducing valve installed at the outlet of a high pressure gas container of a compressed natural gas vehicle and a fuel cell vehicle, and decompresses the high pressure gas from the high pressure gas container (high pressure tank). In addition, a compressed natural gas vehicle and a fuel cell vehicle that can be recovered and used as electric power at the same time will be described below as the best mode for carrying out the present invention.

  In the first embodiment of the present invention, an embodiment of a compressed natural gas vehicle will be described with reference to FIG. In FIG. 1, a compressed natural gas vehicle includes a high-pressure tank 2 for filling and storing compressed natural gas, a scroll expander 3 for decompressing and expanding high-pressure compressed gas from the high-pressure tank 2, and a high-pressure from the high-pressure tank 2. A generator 4 connected to the scroll expander 3 driven by the compressed gas is provided, and the electric power generated by the generator 4 is supplied to the battery 5 of the automobile.

  The high-pressure tank 2 is a plurality of large-capacity gas containers accommodated and installed at the rear of the vehicle, and stores and stores natural gas at a high pressure of 20 MPa (megapascal) in order to extend the cruising range. Usually, a steel seamless container, an aluminum liner composite container (a container in which an aluminum liner is reinforced with fiber reinforced plastic), a plastic liner composite container (common name: all composite container), and the like are used.

  And as fuel piping which connects a fuel from the high pressure tank 2 (gas container) to the engine 1, it is comprised by the thin tubes 2b, such as stainless steel and copper (a part of low pressure part), for example.

  The scroll expander 3 is a positive displacement fluid machine that obtains power by expanding a working fluid. The structure is, for example, arranged so that two scrolls of a fixed scroll and an oscillating scroll constituted by an involute curve, not shown, are engaged with each other, and are high-pressure compressed gas from an air supply port at the center of the fixed scroll. When the working fluid is sucked in, the wall surface of the scroll is pushed by the pressure energy of the fluid, and the expansion chamber moves outward while expanding the working fluid, thereby increasing the volume. In this process, the orbiting scroll orbits while maintaining a fixed eccentric distance with the fixed scroll, and rotates the rotor of the generator 4 connected to the rotation shaft of the crawl expander 3. Thus, mechanical power can be recovered from the energy of the fluid.

  Compressed natural gas vehicles are equipped with a variety of safety devices to ensure safety. For example, there are an overflow prevention valve and a container safety (not shown) valve, a main stop valve 7, a fuel cutoff valve 8, a check valve (not shown), etc., incorporated in the gas container main valve 2a.

  An unshown overflow prevention valve is a valve incorporated in the gas container main valve 2a, and is a device that prevents a large amount of gas from flowing out of the gas container when the fuel pipe or the like is broken.

  The safety valve (not shown) is a valve built into the gas container main valve 2a. If the temperature or pressure of the gas container rises due to a fire or the like, the fusible plug (the plug made of an alloy that melts when the temperature exceeds a certain temperature) melts. It is a device that safely discharges gas from the gas container 2.

  The main stop valve 7 is installed near the gas container main valve 2a on the high-pressure pipe, and determines an abnormality (failure) in the fuel pressure according to a change in pressure downstream from the scroll expander 3, and an output abnormality is detected. In an emergency, the valve is closed by de-energization of the coil 7a and the fuel supply to the engine 1 is automatically shut off.

  The fuel cutoff valve 8 is installed near the scroll expander 3 on the high-pressure pipe, and shuts off the fuel supply to the engine 1 when the engine is stopped.

  The fuel pipe 2b from the gas container 2 extends forward of the vehicle, communicates with the pressure gauge 6 in the driver's seat via a pressure sensor, and communicates with the fuel cutoff valve 8. When the engine is stopped, the fuel cutoff valve 8 is closed when the coil 8a is not energized to shut off the compressed natural gas, and is opened when the coil 8a is energized to supply the natural compressed gas.

  The fuel for the engine 1 is supplied to the engine 1 by mixing air and natural gas by the injector 1a according to the engine load. However, for natural compressed gas vehicles, if natural gas is supplied at a pressure higher than atmospheric pressure, it will not be possible to inhale air in the engine intake system. For this reason, the high-pressure compressed natural gas of 20 MPa that is filled and stored in the gas container 2 is reduced to, for example, about 0.5 MPa to 3.25 MPa (0.4 MPa in this embodiment), and the energy generated by this large pressure difference is reduced. Utilizing the scroll expander 3 that is rotationally driven by gas expansion, the pressure energy can be recovered efficiently.

  The scroll expander 3 injects high-pressure compressed natural gas from the center of the scroll rotor, creates a narrow space by combining the spiral rotor and the wall, confines the high-pressure compressed natural gas, and The circular motion is performed by expanding the confined space outward. Using this rotation, the generator rotor connected to the rotary shaft of the scroll expander 3 can be rotated and driven to rotate by the pressure expansion of the compressed natural gas. It is provided so that the pressure is reduced to low pressure gas.

  The generated power generated by the scroll expander 3 can be used not only for charging the battery 5 but also for the operation of various lighting devices such as headlights, safety devices, air conditioners, etc. Can be improved.

  Next, the operation of this embodiment will be described. First, when the container main valve 2a of the gas container 2 is opened, the high-pressure compressed natural gas stored in the gas container 2 of the high-pressure tank is introduced into the fuel pipe 2b. The compressed natural gas passes through the main stop valve 7 and the gas filling state is displayed on the pressure gauge 6 in the driver's seat via the pressure sensor 6a.

  Next, when the engine is stopped, the coil 8a is deenergized to close the fuel cutoff valve 8, and the compressed natural gas is shut off. At the start of the engine, the coil 8a of the fuel cutoff valve 8 is energized and opened by its electromagnetic force. Then, high-pressure compressed natural gas of about 20 MPa is injected into the center of the scroll expander 3.

The compressed natural gas injected into the central portion first passes through a space composed of two scrolls (spirals), with the compressed natural gas of 20 MPa gradually expanding outward to a low pressure of 0.4 MPa. Rotational force (for example, rotation speed 3000 rpm) due to the expansion is transmitted to the generator 4 attached to the shaft of the scroll expander 3 to generate electric power. That is, when high-pressure compressed natural gas is injected into the inlet of the scroll expander 3, a differential pressure is generated between the outlet and the outlet, and the scroll enlarges the expansion chamber by the differential pressure.
As a result, large pressure energy possessed by the compressed natural gas in the normal decompression process can be efficiently recovered as the power of the scroll expander 3. In addition, the scroll expander 3 is characterized by extremely high silence, and can be said to be optimal for an automobile.

The low-pressure gas decompressed by the scroll expander 3 is flow-controlled by the injector 1a and mixed well with air, and is supplied to the engine 1 to start operation. During the engine operation, the generator 4 connected to the rotor of the scroll expander 3 is driven, so that the power generated by the generator 4 is charged in the battery 5. In addition, the generated power can be supplied to a lighting device of an automobile so as to be lit and supplied to an air conditioner having a large electric load. As a result, the engine load is reduced and the fuel consumption can be improved.
Note that the pressure sensor 7 detects the reduced pressure state by the scroll expander 3 during engine operation, and the main stop valve 7 is closed in an emergency to automatically cut off the fuel supply to the injector 1a.

  In the scroll expander 3, the air-fuel ratio can be adjusted by adjusting the supply pressure of the decompressed fuel gas. That is, the mixing composition of air and fuel gas is controlled by changing the rotational speed of the scroll expander 3 and changing the pressure difference between the inlet and outlet of the scroll expander 3 according to the driving condition of the automobile. The fuel gas supplied to the engine 1 can be optimally supplied and controlled.

  Next, a second embodiment of the present invention will be described with reference to FIG. The fuel cell vehicle according to the present invention is a vehicle that uses hydrogen or reformed hydrogen as fuel from the fuel cell and reacts with oxygen in the air to generate electricity and drive the electric motor. The configuration includes a high-pressure tank 20 that is a hydrogen reservoir that fills and stores compressed hydrogen, a scroll expander 30 that decompresses and expands high-pressure compressed hydrogen from the high-pressure tank 20, and compressed hydrogen from the high-pressure tank 20. A generator 40 connected to the driven scroll expander 30 is provided, and the electric power generated by the generator 40 is configured to be supplied to the battery 50 of the automobile.

  The fuel cell vehicle is different from the first embodiment in that there is no engine provided with an injector, and a fuel cell 60 and an electric motor (generator) 70 are provided. Further, the description overlapping with the first embodiment is omitted.

  The hydrogen storage 20 is a cylinder of a high-pressure tank capable of storing hydrogen at a pressure of about 10 to 150 atm. For example, a carbon-based material such as a hydrogen storage alloy, carbon nanotube, carbon nanofiber, or graphite nanofiber is used. .

  Then, by opening a valve (not shown) of the hydrogen reservoir 20, high pressure hydrogen is injected into the scroll expander 30 to drive it, and the high pressure hydrogen is reduced to a constant pressure by the scroll expander 30. Thus, the hydrogen whose flow rate has been adjusted is supplied to the fuel cell 60 or the generator 40.

  The fuel cell 60 is similar in function to an existing storage battery, but replenishes hydrogen instead of charging. For example, there are different types of fuel cells such as a solid polymer type, a direct methanol type, a phosphoric acid type, a carbonated molten salt type, a solid oxide type, and a regeneration type.

  Even when the generator 40 is connected to generate power with the rotational power of the scroll expander 30 as in the first embodiment, the hydrogen supplied from the scroll expander 30 is driven as fuel and hydrogen is generated by the power. It may be an engine generator.

  In addition, an electric motor (generator) 70 for performing motor running using electric energy obtained from the fuel cell 60 is provided. Then, during acceleration, power is supplied from the fuel cell 60 and the battery 50 to improve power performance, and during traveling, power distribution is optimized from the fuel cell 60 and the battery 50 to improve the energy efficiency of the automobile. Further, at the time of deceleration, the electric motor 70 functions as the generator 70, performs regeneration to convert braking energy into kinetic energy of the vehicle body of the automobile into electric energy, and is provided in the battery 50 to improve the energy efficiency of the automobile.

  As the battery 50, for example, a superconducting battery with good power storage efficiency is used.

  As described above, the compressed natural gas fueled vehicle of the first embodiment is provided with the scroll expander that recovers the pressure energy as power in the process of decompressing the high-pressure compressed natural gas. The large pressure energy possessed by the gas can be used effectively. Further, the scroll expander 3 can efficiently recover gas pressure energy as power. Since the scroll expander 3 is merely provided in the gas pipe instead of the pressure reducing valve, the structure is simple.

  In addition, since the power generator that operates the electric load of the automobile has the configuration of the generator 4 that is connected so as to generate power with the rotational power of the scroll expander shaft, the recovered power can be effectively used for power generation. As a result, the engine load can be reduced and fuel consumption can be improved.

  In the fuel cell vehicle of the second embodiment, the scroll expander 30 is first driven by the high pressure hydrogen supplied from the hydrogen reservoir 20 to generate power, and the high pressure hydrogen is reduced by the scroll expander 30. The decompressed hydrogen can be supplied to the fuel cell 60. Alternatively, it can be supplied to a hydrogen engine generator for power generation and stored in a battery, and any of the hydrogen supplied from the hydrogen reservoir 20 can be effectively used to improve power generation efficiency.

1 Engine 2 High-pressure tank (gas container)
3,30 Scroll expander 4,40 Generator 5,50 Battery 20 High pressure tank (hydrogen storage)
60 Fuel cell 70 Electric motor (generator)

Claims (2)

In an automobile power generator using a compressed gas of natural gas or hydrogen gas as fuel,
A high-pressure tank for filling and storing the compressed gas;
A scroll expander that decompresses and expands the compressed gas from the high-pressure tank;
A generator coupled to the scroll expander driven by the compressed gas;
A power generator for an automobile, wherein the electric power generated by the generator is supplied to a battery of the automobile. An automobile comprising the power generator of the automobile according to claim 1.

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