JP2000028218A - Onboard refrigeration circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectually utilize cold heat produced when natural gas is supplied to an engine which uses the natural gas as a fuel. SOLUTION: A gas bomb and an engine are connected with each other in 2 systems 110, 120, and it is controlled through which system natural gas is sent to the engine through a changeover valve 100. In the first system 110 there are provided a first pressure reducer 111, a heat exchanger 112, and a fan 113, while in the second system there is provided a second pressure reducer 121. Hereby, upon the use of a car air conditioner the natural gas from a gas cylinder is reduced in pressure using the first pressure reducer 111 into low temperature low pressure gas which is in turn supplied to the heat exchanger 11. In the heat exchanger 112 the gas is subjected to heat exchange with car air and is supplied to the engine.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigeration circuit in a natural gas vehicle that runs using natural gas supplied to a gas cylinder as fuel.

[0002]

2. Description of the Related Art In recent years, natural gas, which has been increasingly consumed as clean energy, has been attracting attention as a fuel for automobiles because it can be expected to reduce air pollution.

[0003] In such a natural gas vehicle, as shown in FIG.
The power is generated by decompressing the gas to zero and gasifying it, and then burning it with the engine.

On the other hand, most automobiles are equipped with a car air conditioner as standard. As shown in FIG. 7, the car air conditioner includes a compressor 210 for compressing a refrigerant, a condenser 211 for exchanging heat between the compressed refrigerant and the outside air, a decompression device 213 for decompressing the refrigerant from the condenser 211, and a decompression device 213. Evaporator 214 for evaporating the refrigerant from the vehicle, a fan 21 that draws air inside the vehicle, sends it to the evaporator 214, and blows the air into the vehicle.
5 and the like, and the compressor 210 is driven by an engine.

[0005]

However, when the natural gas is depressurized by the pressure reducing valve 200, the temperature of the natural gas drops, so that the gas supply port of the engine is cooled and a lot of cold energy is wasted. Has a problem that frost adheres to the surface.

On the other hand, in a car air conditioner, a compressor 2
Since the power of No. 10 is supplied from the engine, there is a problem that fuel efficiency and the like are reduced by that amount.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vehicle-mounted refrigeration circuit capable of effectively utilizing cold heat and suppressing a decrease in fuel efficiency or the like caused by driving a compressor.

[0008]

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to an in-vehicle refrigeration circuit for vaporizing natural gas from a gas cylinder and supplying the gas to the engine as fuel. A decompression device that decompresses natural gas from the gas cylinder,
A heat exchanger that is provided between the decompression device and the engine and exchanges heat between the supplied natural gas and air is provided to enable effective use of cold generated at the time of fuel supply. I do.

According to a second aspect of the present invention, the piping connecting the gas cylinder and the engine comprises two systems, and a heat exchanger is provided in one of the systems to enable effective utilization of cold generated during fuel supply. Features.

[0010] The invention according to claim 3 is provided with flow rate adjusting means for adjusting the flow rate of natural gas flowing through these two systems at the branch point of the two systems, thereby enabling the effective use of cold generated at the time of fuel supply. It is characterized by the following.

[0011] The invention according to claim 4 is characterized in that the flow rate adjusting means is a switching valve for setting in which system natural gas flows.

The invention according to claim 5 is characterized in that the flow rate adjusting means is a flow rate adjusting valve for adjusting the flow rate of natural gas flowing through these two systems.

According to a sixth aspect of the present invention, the decompression device comprises:
It is characterized by being provided in each of the piping of the system.

[0014] The invention according to claim 7 is characterized in that a pressure reducing device is provided in the middle of the pipe between the two branch points and the gas cylinder.

The invention according to claim 8 is characterized in that the pipe connecting the gas cylinder and the engine is constituted by one system.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a refrigeration circuit diagram for a vehicle according to the present invention. In the following description, a car air conditioner will be described as an example of a refrigerating device, but the present invention is not limited to this, and it is added that the present invention is applicable as long as it uses cold air such as a refrigerator.

In the refrigeration circuit shown in FIG. 1, a gas cylinder and an engine are connected by two systems 110 and 120, and a switching valve 1 is provided.
00 controls which system sends natural gas to the engine.

The first system 110 has a first decompression device 111 for expanding or squeezing the natural gas filled in the gas cylinder by liquefaction, and heat for exchanging heat between the natural gas from the first decompression device 111 and the vehicle interior air. Exchanger 112, fan 1 for blowing air so that air inside the vehicle circulates through heat exchanger 112
13 and the like are provided.

On the other hand, the second system 120 is provided with a second decompression device 121 for liquefying and expanding or squeezing the natural gas filled in the gas cylinder.

The switching valve 100 is formed of an electromagnetic valve or the like so that it can be electronically controlled. When a car air conditioner is used while a natural gas vehicle is running, natural gas is supplied to the engine via the first system 110. When the car air conditioner is not used, natural gas is supplied to the engine via the second system 120.

Thus, when the car air conditioner is used, the natural gas from the gas cylinder is decompressed by the first decompression device 111 and supplied to the heat exchanger 112 as a low-temperature low-pressure gas. Heat is exchanged with air and supplied to the engine. Thereby, the air inside the vehicle is cooled, and the inside of the vehicle is cooled.

Therefore, the compressor used in the conventional car air conditioner is not required, and the power for driving the compressor is not required, so that the cost and the fuel consumption can be improved, and the cooling and heating can be performed. Effective use becomes possible.

Various methods are conceivable to make the cooling temperature adjustable. For example, it is possible to control the wind force of the fan 113 or to use a flow rate adjusting valve capable of adjusting the flow rate instead of the switching valve 100. Is possible.

In the above description, the first system 110 and the second system
Although the case where the system 120 is used has been described, the present invention is not limited to this.
It may be just.

With such a configuration, the number of pressure reducing devices can be reduced to one and the cost can be reduced. In this case, the natural gas from the gas cylinder is constantly supplied to the engine via the heat exchanger 112. Therefore, when the cooling is not performed, the fan 113 is stopped. Can be adjusted.

Further, even in the case of using two systems, FIG.
It is obvious that the system branch may be performed after the pressure reducing device 130 as shown in FIG.

Next, a filling device for filling such a natural gas into a cylinder will be described. FIG. 3 shows a configuration of a natural gas filling apparatus. In order to increase the filling efficiency, two compressors 7 are installed in parallel, and a check valve 15 is provided on each discharge side, and a suction side and a suction side are provided. The discharge side downstream of the check valve 15 is communicably connected by a solenoid valve 8A shown in detail in FIGS.

In FIG. 4, reference numeral 20 denotes a valve body formed of a metal material. The valve body 20 has an inlet-side fluid passage 23 and an outlet-side fluid passage having a gas inlet 21 and a gas outlet 22 opened at both left and right end surfaces, respectively. 24 are formed.

The axial valve hole 2 which is located at the inner end of the inlet-side fluid passage 23 and intersects with the inlet-side fluid passage 23
One end of the valve hole 5 is open, and the other end of the valve hole 25 is open to a valve chamber 26 communicating with the outlet-side fluid passage 24.

A valve body 29 having a spherical portion 28 for closing or opening the valve hole 25 by coming into contact with or separating from an annular valve seat portion 27 at the multi-end opening edge of the valve hole 25 is fitted in the valve chamber 26 so as to be able to advance and retreat. Have been combined.

In the main body 20, the inner ends of a plurality of pressing operation holes 30 are opened in the valve chamber 26 so as to be opposed to the valve body 29, and are separated from the valve holes 25. Valve body 20
It has an opening on the upper surface.

Reference numeral 31 denotes an electromagnetic device. The electromagnetic device 31 is composed of an electromagnetic coil 32 and a fixed iron core 33 disposed at a center position of the electromagnetic coil 32, and is excited by energizing the electromagnetic coil 32. Accordingly, a plunger 34 drawn toward the fixed iron core 33 is provided, and an operating rod portion 35 is provided at a tip end of the plunger 34 so as to be inserted into each pressing operation hole 30 so as to be able to advance and retreat.

Further, between the upper end of the plunger 34 and the lower end of the fixed core 33, the plunger 34 is separated from the fixed core 33, and the operating rod 35 is projected from the pressing hole 30 so that the valve body 29 is moved. A coil-shaped first spring 36 for applying a pressing force downward in the drawing is provided.

The valve chamber 26 has a coil-like shape for urging the valve body 29 between the valve body 29 and a spring receiver 37 screwed into the valve chamber 26 in a direction in which the valve body 29 closes the valve hole 25. The second spring 38 is provided.

Incidentally, the urging force given by the first spring 36 is weaker than the pulling force by the electromagnetic device 31, and
Is selected to be larger than the urging force of the spring 38 of FIG. The urging force of the second spring 38 is related to the relief pressure, the cross-sectional area corresponding to the diameter of the valve hole 25 in the valve body 29, and the gas pressure (high-pressure side pressure) of the inlet-side fluid passage 23 serving as the primary side. And outlet-side fluid passage 2 serving as a secondary side
4 is obtained by the product of the pressure difference of the gas pressure (low pressure side pressure) and the safety coefficient. In this case, when the pressure difference is, for example, 22 MPa or more, the valve body 29 is pressed downward in the drawing, and the valve hole is pressed. 25 is opened.

Further, there is no power supply to the electromagnetic device 31,
Therefore, in a state where the gas inlet 21 and the gas outlet 22 are in bidirectional communication, the gas pressure in the outlet-side fluid passage 24 rises higher than the gas pressure in the inlet-side fluid passage 23, and the gas outlet 22
When a large amount of gas starts flowing in the direction of the gas inlet 21 from
The valve body 29 is sucked into the portion of the valve hole 25 where the flow velocity increases and the pressure drops, the valve hole 25 is closed, and the first and second springs are closed so that the gas outlet 22 is disconnected from the gas inlet 21. It is configured.

The plunger 34 of the electromagnetic device 31
The plunger 34 is located below the
The upper end of the guide tube 40 for guiding the screw is screwed and fixed. The nut 4 fitted to the guide tube 40
1 is engaged with a flange portion 42 formed at a lower end portion of the guide tube 40, and the nut 41 is screwed to the valve body 20 to fix the electromagnetic device 31 to the valve body 20. In this state, the O-ring 44 is interposed at the joint between the valve body 20 and the flange 42 of the guide tube 40 to ensure airtightness.

The flux plates 45 and 46 are in contact with the upper and lower portions of the electromagnetic coil 32, respectively.
2 is covered with a housing cover 47,
7 is fixed by screws 48 screwed to the fixed iron core 33.

Therefore, as shown in FIGS. 4 and 5 (a), the solenoid valve 8A having the above-described configuration allows the first spring 3
6, the plunger 34 is depressed and moved downward from the fixed core 33 in the drawing.
The operating rod 35 protrudes from the pressing operation hole 30 into the valve chamber 26, and the operating rod 35 presses the valve body 29 downward against the second spring 38 to open the valve hole 25, and the gas inlet 21 is opened. The gas outlet 22 communicates via the valve chamber 26.

When the electromagnetic device 31 is energized to excite the electromagnetic coil 32, the plunger 34 is attracted to the fixed core against the urging force of the first spring 36, as shown in FIG. Since the distal end of the operating rod portion 35 of the plunger 34 is retracted from the valve chamber 26 and the downward pressing of the valve body 29 in the drawing is released, the valve body 29 is pressed upward by the urging force of the second spring 38 so that the valve is pressed. The hole 25 is closed, and the gas inlet 21 and the gas outlet 22 are disconnected.

However, the electromagnetic device 3 which is turned off and not energized
When the pressure of the outlet-side fluid passage 24 becomes higher than the pressure of the inlet-side fluid passage 23 when the gas inlet 21 and the gas outlet 22 communicate with each other at the time of the non-excitation of the valve 1, the valve body 29 closes the valve hole 25. When the gas outlet 22 and the gas inlet 21 side are disconnected from each other, and the gas inlet 21 and the gas outlet 22 are disconnected by the excitation operation of the electromagnetic device 31 at the time of energization, the pressure of the inlet-side fluid passage 23 is increased. When the pressure becomes higher than the pressure in the inlet-side fluid passage 23 (in this case, 22 MPa or more), the pressure acting on the valve element 29 from the valve hole 25 as shown in FIG.
9 is pressed downward in the drawing against the urging force of the second spring 38, the valve hole 25 is opened, and the gas inlet 22 and the gas outlet 22 communicate with each other.

That is, the solenoid valve 8A allows the gas inlet 21 and the gas outlet 22 to communicate with each other when the power supply is turned off (when the pressure of the outlet fluid passage 24 becomes higher than the pressure of the inlet fluid passage 23, It has a function of disconnecting the gas inlet 21 from the gas outlet 22 when the power is turned on, and has a function of exciting the electromagnetic device 31 when the power is turned on. When the valve element 29 closes the valve hole 25 by the urging force of the second spring 38 and the gas inlet 21 and the gas outlet 22 are shut off,
When the pressure on the side of the gas inlet 21 rises beyond the pressure on the side of the gas outlet 22 by a predetermined pressure, in this case, over 22 MPa, the pressure acts on the valve body 29 from the valve hole 25 as shown in FIG. The valve body 29 is pressed downward against the urging force of the second spring 38 by the pressure, and the valve hole 25 is opened so that the gas inlet 21 and the gas outlet 22 communicate with each other.

Reference numeral 16 denotes a controller (not shown) for operating / stopping the compressor 7 by operating a button switch or the like.
Is opened, and the solenoid valve 8A is energized to shut off the gas inlet 21 and the gas outlet 22. Further, when the pressure on the discharge side pipe measured by the pressure sensor 12, that is, the pressure between the discharge side of the compressor 7 and the coupling 2 reaches a predetermined pressure, for example, 20 MPa, the operating compressor 7 is stopped. , The solenoid valve 3 is closed, and the power supply to the solenoid valve 8A is stopped.

The operation of the compressor 7 is controlled by the pressure switch 1
The power supply to the compressor 7 is automatically cut off by the operation of the compressor 3, and the compressor 7 is automatically stopped. The pressure at which the pressure switch 13 operates is about 21 MPa, for example, 1 MPa lower than the pressure difference of 22 MPa when the valve body 29 of the electromagnetic valve 8A is pressed downward in the drawing and the valve hole 25 is opened when energized. Is set to
When the compressor 7 is automatically stopped by the operation of the pressure switch 13, the solenoid valve 3 is closed and the solenoid valve 8 is closed.
The controller 16 is provided so as to stop energization of A.

By using the natural gas filling apparatus having the above-described configuration, natural gas at a low pressure (for example, slightly higher than the atmospheric pressure) stored in, for example, a gas tank 50 is converted into a small gas container loaded on an automobile 60. Gas cylinder 61
The procedure for compression filling is described below.

The coupling 1 includes a coupling 5 provided at the tip of a gas introduction pipe 51 provided from a gas tank 50.
And the other coupling 2 in general.
Is connected to the coupling 64 of the motor vehicle 60 that needs to be refilled with natural gas.

Before opening the on-off valve 63 of the automobile 60, the pressure sensor 12 or the pressure gauge 14 first monitors the pressure change in the discharge side pipe. Since the pressure sensor 12 and the pressure gauge 14 have detected the pressure of the natural gas remaining in the discharge-side pipe at the time of the previous gas filling, if a pressure drop is confirmed after connection, the connection between the couplings 2 and 64 is established. Since a gas leak has occurred at the connection portion, the alarm 17 is operated to notify the user of the alarm.

For example, it is confirmed by a comparison operation unit (not shown) of the controller 16 that the speed and width of the pressure change measured by the pressure sensor 12 are equal to or less than a predetermined value, or visually confirmed by the pressure gauge 14. Then, the on-off valve 63 is manually opened.

When it is confirmed that a gas leak has occurred at the connection between the couplings 2 and 64, appropriate measures such as reconnection and repair of the couplings 2 and 64 are performed. Operation will be performed.

The on-off valve 63 is opened and the couplings 2, 6
The change in the pressure in the discharge-side pipe is monitored in the same manner as when the connection 4 is connected, and it is confirmed whether or not the check valve 62 is functioning normally. If the check valve 62 is malfunctioning and there is a gas leak, the pressure in the discharge-side pipe rises. In this case as well, the alarm 17 is operated to notify the operator and the filling operation is stopped.

After confirming that the pressure change in the discharge pipe is within the normal range, the controller 16 is operated to operate the compressor 7.
Start. When the capacity of the gas cylinder 61 is large, two compressors 7 are started simultaneously, and when the capacity of the gas cylinder 61 is small, only one of the compressors 7 is started.

When the compressor 7 is started, natural gas stored in the gas tank 50 is supplied to the gas introduction pipe 51 and the compressor 7.
Flows into the compressor 7 via the solenoid valve 3 and the blowdown tank 6 which are opened prior to the activation of the gas cylinder 61, is compressed therein, passes through the couplings 2, 64, the opening valve 63, the check valve 62 and the gas cylinder 61. Is compressed and filled.

As the amount of natural gas filled in the gas cylinder 61 increases, the pressure measured by the pressure sensor 12 increases, and when the pressure reaches a predetermined pressure, in this case, 20 MPa.
The operation of the compressor 7 is automatically stopped by a control signal transmitted from the controller 16, and the solenoid valve 3 is closed. The pressure in the discharge-side pipe during the compression filling can be visually confirmed by the pressure gauge 14.

When the operation of the compressor 7 is stopped, the controller 16
The power supply to the solenoid valve 8A is stopped based on the control signal transmitted by the controller, the gas inlet 21 and the gas outlet 22 are communicated with each other, and the high-pressure natural gas that has been compressed to 20 MPa and remains in the discharge-side pipe is removed. It flows into the blowdown tank 6 to lower the pressure of the high pressure side pipe.

Since the blow-down tank 6 is formed to have a sufficiently large internal volume, for example, about 6 liters, in comparison with the internal volume of the discharge side pipe, the pressure between the check valves 5 and 62
That is, the pressure measured by the pressure sensors 11 and 12 is 300
It decreases to about kPa.

Then, the solenoid valve 8A is energized again, and the pressure sensor 1 is turned on with the gas inlet 21 and the gas outlet 22 shut off.
For a while, the change in the pressure measured by 1, 12 is monitored, and it is confirmed that both the speed and the width of the change are equal to or less than a predetermined value. Thereafter, the on-off valve 63 is manually closed. It may be visually confirmed by the pressure gauge 14.

When a pressure increase is confirmed in the discharge-side pipe with the gas inlet 21 and the gas outlet 22 disconnected, even if gas leakage has not been detected before filling, it is possible to perform high-pressure filling after filling. Since a gas leak has occurred in the check valve 62, the alarm 17 is operated to notify the driver of the gas leak in this case, and is transmitted to the driver to prompt prompt repair of the check valve 62.

Finally, the couplings 2 and 64 are disconnected, and a series of natural gas filling operations is completed. Since the disconnection between the couplings 2 and 64 has been reduced to about 300 kPa as the pressure in the discharge side pipe has been,
There is no danger.

The above-mentioned natural gas filling operation is completed.
Even if the pressure in the discharge-side pipe suddenly drops due to some abnormality while waiting for the next filling, and a large pressure difference occurs between the outlet-side fluid passage 24 and the inlet-side fluid passage 23,
Since the electromagnetic valve 8A is disconnected from the gas outlet 22 to the gas inlet 21, the natural gas returned to the blowdown tank 6 or the like after compression filling does not leak through the electromagnetic valve 8A.

Also, the solenoid valve 8A is energized and the gas inlet 21
When the compressor 7 is started and the natural gas is compressed and charged, the pressure sensor 12, the pressure switch 13 and the like are malfunctioning, and the pressure in the discharge-side pipe is reduced. When the pressure starts to rise above a predetermined pressure (22 MPa in this case), the valve body 29 is pressed downward in the drawing, the valve hole 25 is opened, and the gas inlet 21 and the gas outlet 22 communicate with each other. Abnormal pressure rise on the side is prevented.

By the way, when it is confirmed before the gas filling that the check valve 62 is malfunctioning and there is a gas leak, the check valve 62 is checked.
It is desirable to fill the battery after repairing or replacing it with a normal one. However, if the controller 16 is set so that the power supply to the solenoid valve 8A can be manually stopped, the filling is performed.
After the compressor 7 reaches the predetermined 20 MPa and automatically stops, the on-off valve 63 is closed first, and then the energization to the solenoid valve 8A is stopped to allow the gas inlet and the gas outlet 22 to communicate with each other. The high-pressure natural gas remaining in the discharge-side piping between the discharge side of the compressor 7 and the on-off valve 63 can flow into the blowdown tank 6, and the gas cylinder 6
It is possible to prevent the backflow from 1 and safely reduce the pressure in the discharge side pipe.

The pressure in the blow-down tank 6, which does not have a pressure resistance structure, is reduced to a predetermined pressure, for example, 600 kPa, by the natural gas flowing from the discharge side to the suction side of the compressor 7 through the solenoid valve 8A. It is opened when it rises to protect the natural gas accumulated in the blow-down tank 6 by discharging it into the atmosphere, for example.

[0063]

As described above, according to the present invention,
Since a heat exchanger is provided in the line that supplies natural gas to the engine by decompressing or squeezing natural gas from the gas cylinder, the natural gas does not exchange heat with air and the engine does not cool down. Does not require a compressor and does not require power for driving the compressor.

[Brief description of the drawings]

FIG. 1 is a refrigeration circuit diagram applied to an embodiment of the present invention.

FIG. 2 is a refrigeration circuit diagram applied to the description of another embodiment.

FIG. 3 is a schematic configuration diagram of an apparatus for filling natural gas.

4 is a vertical sectional front view of a solenoid valve in the filling device of FIG. 3;

5 is a vertical sectional front view showing an operation of a valve body in the solenoid valve of FIG.

FIG. 6 is a gas supply circuit of a natural gas vehicle applied to the description of the related art.

FIG. 7 is a refrigeration circuit diagram of the car air conditioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 100 Switching valve 110 1st system 111 1st decompression device 112 Heat exchanger 113 Fan 120 2nd system 121 2nd decompression device 130 Decompression device

Claims (8)

[Claims] An in-vehicle refrigeration circuit for vaporizing natural gas from a gas cylinder and supplying it to an engine as fuel, a pressure reducing device for reducing the pressure of the natural gas from the gas cylinder in the middle of a pipe connecting the gas cylinder and the engine, A vehicle-mounted refrigeration circuit comprising: a heat exchanger provided between the decompression device and the engine to exchange heat between supplied natural gas and air. 2. The on-vehicle refrigeration circuit according to claim 1, wherein the pipe connecting the gas cylinder and the engine comprises two systems, and the heat exchanger is provided in at least one of the systems. 3. The in-vehicle refrigeration circuit according to claim 2, wherein a flow rate adjusting means for adjusting natural gas flowing through these two systems is provided at the branch point of the two systems. 4. The on-vehicle refrigeration circuit according to claim 3, wherein said flow rate adjusting means is a switching valve for setting in which system natural gas flows. 5. The on-vehicle refrigeration circuit according to claim 3, wherein said flow rate adjusting means is a flow rate adjusting valve for adjusting a flow rate of natural gas flowing through said two systems. 6. The pressure reducing device is provided in each of the two systems of pipes.
The refrigeration circuit for a vehicle according to claim 1. 7. The in-vehicle refrigeration circuit according to claim 2, wherein a decompression device is provided in the middle of a pipe between the two system branch points and the gas cylinder. 8. The in-vehicle refrigeration circuit according to claim 1, wherein a pipe connecting the gas cylinder and the engine is formed of one system.