JPH0539262Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fuel supply device for automobiles that uses compressed natural gas (CNG) as fuel.

[Prior Art] Vehicles that use CNG as fuel are at an experimental stage in Japan, and there are currently only a few filling stations that fill the fuel cylinders of these vehicles. However, the portable high-pressure containers (cylinders) used in fuel cylinders are widely used for industrial purposes, and there are many filling stations for them.
For both types of filling methods, the compressor and cylinder are directly connected through a supply line, and the compressor gradually fills the cylinder (time-filling method), and the compressor discharge gas is temporarily stored in a pressure accumulator, and the cylinder is filled from there. There is a rapid filling method. There are also two rapid filling methods. One is to maintain the accumulator pressure at the maximum filling pressure of the cylinder, and when filling, fill without controlling the filling pressure, so that the pressure in the accumulator and cylinder are the same. This is a method that sometimes ends filling. In this filling method, the pressure in the accumulator decreases as the compressor discharge rate is lower than the filling flow rate, so in order to fill the cylinder at the maximum filling pressure, it is necessary to switch the filling line and perform additional filling directly with the compressor. There is. Another method is to keep the pressure in the pressure accumulator sufficiently higher than the maximum filling pressure of the cylinder, and close the shutoff valve between the pressure accumulator and the cylinder just before the cylinder filling pressure reaches the maximum filling pressure when filling. It is a method.

Figure 2 shows the latter rapid filling method, where 101 is a pressure accumulator, 102 is a fuel filling line,
103 is a fuel cylinder loaded in a car, 104
is a pressure gauge attached to the fuel filling line 102. Gas is charged from the pressure accumulator 101 to the fuel cylinder 103 using the pressure accumulated in the pressure accumulator 101, and the pressure gauge 104 reaches a predetermined pressure. When this is reached, the shutoff valve 105 is manually or automatically closed to complete the filling process.

[Problems Required in the Prior Art] The pressure accumulator 101 stores the pressure of the gas compressed by the compressor during the operating hours, and temporarily compresses the gas during filling concentrated during a part of the compressor operating hours. This system is designed to allow filling without lowering the specified filling pressure even if the filling amount significantly exceeds the discharge amount of the accumulator.
Since the fuel cylinder 103 is filled with a pressure of 1, the pressure with which the fuel cylinder 103 is filled does not exceed the pressure of the pressure accumulator 101. For this reason, if the filling frequency increases, the pressure accumulator 1
01 pressure decreases, and the pressure at which it is possible to fill the fuel cylinder 103 decreases. At this time, the capacity of the pressure accumulator 101 can be expressed as the difference between the maximum accumulated pressure of the pressure accumulator 101 and the pressure of the pressure accumulator 101 after filling, multiplied by the geometric volume of the pressure accumulator 101. However, the accumulator pressure after filling is
When the maximum filling pressure of 03 is lowered, the fuel cylinder 103
Since the pressure accumulator 101 cannot be completely filled, the pressure accumulator 101 is
In the conventional system, in order to increase the capacity of the pressure accumulator 101, it was necessary to increase the maximum accumulated pressure of the pressure accumulator 101 or increase the geometric volume of the pressure accumulator 101.

Of course, if the possible filling pressure decreases in this way, it is possible to switch the filling line and directly fill the compressor with additional filling, but if such an additional filling method is adopted, the procedure is troublesome. In addition, there is a problem that filling takes time.

On the other hand, the fuel cylinder 103 to be filled starts filling when it is almost empty or when the pressure has dropped to the point that it requires replenishment. The pressure does not need to be higher than the filling pressure, but may be any pressure that can be filled with the cylinder filling start pressure.

An object of the present invention is to provide a fuel supply device that can supply sufficient pressure to a fuel cylinder in a shorter period of time even when the capacity of a pressure accumulator is insufficient in the conventional system.

[Means to solve the problem] The configuration of the present invention is as follows.

A pressure accumulator for storing compressed natural gas is divided into a high pressure pressure accumulator and a variable pressure pressure accumulator, a high pressure filling line and a variable pressure filling line are extended from the high pressure pressure accumulator and the variable pressure pressure accumulator, respectively, and are joined in the middle, By extending this point, a fuel filling line that can be freely connected to the filling port of a fuel cylinder of an automobile is provided, and a high pressure switching valve is installed on the high pressure filling line, and a variable pressure switching valve is installed on the variable pressure filling line. A pressure gauge is attached to the fuel filling line, and at the beginning of filling, the variable pressure switching valve is opened, the high pressure switching valve is closed, and compressed natural gas is filled into the vehicle fuel cylinder using the pressure of the variable pressure accumulator. When the pressure gauge detects that the pressure has reached a certain level, the high pressure switching valve is opened, the variable pressure switching valve is closed, and the pressure in the fuel cylinder reaches the specified pressure using the pressure in the high pressure accumulator. A fuel supply device for a vehicle that uses compressed natural gas as fuel, characterized in that it is provided with a controller that controls the supply.

[Operation] When starting fuel supply, the controller first closes the high pressure switching valve, opens the variable pressure switching valve, and fills the variable pressure accumulator from the variable pressure accumulator side with the pressure of the variable pressure accumulator.

Then, this filling pressure is detected by a pressure gauge, and when the rate of increase in pressure becomes small, or when the pressure difference between the pressure detected by the pressure gauge and the variable pressure accumulator becomes small, the variable pressure switching valve is activated. Close the high-pressure switching valve, switch the filling pressure to the high-pressure accumulator side, and continue filling until the pressure rises to a predetermined level.

[Example] FIG. 1 shows an embodiment of the present invention.

Code 1 is high pressure accumulator, 2 is variable pressure accumulator, 3
4 is a high pressure filling line, 4 is a variable pressure filling line, 5 is a fuel filling line, and 6 is a fuel cylinder loaded on the automobile 7.

Numeral 8 is a high pressure switching valve attached to the high pressure filling line 3, 9 is a variable pressure switching valve attached to the variable pressure filling line 4, 10 is a pressure gauge, and 11 is a controller, which performs the following control.

When filling the fuel cylinder 6 of the automobile 7 with fuel, the high pressure switching valve 8 is initially closed, the variable pressure switching valve 9 is opened, and the pressure of the variable pressure accumulator 2 is filled into the fuel cylinder 6. Then, this filling pressure is detected by the pressure gauge 10, and when the rate of pressure increase becomes small or the pressure difference between the pressure detected by the pressure gauge 10 and the variable pressure accumulator 2 becomes small, this signal is sent. In response, the controller 11 closes the variable switching valve 9 and opens the high-pressure switching valve 8 to fill the high-pressure accumulator 1 with pressure, and when the pressure in the fuel cylinder 6 reaches a predetermined pressure, closes the high-pressure switching valve 8. Close 8.

[Effects of the invention] As described above, the present invention provides a variable pressure accumulator in a high pressure accumulator, and initially fills from the variable pressure accumulator side.
In order to raise the pressure to a predetermined level, the system switched to the high-pressure accumulator side for filling.

In the example, the maximum accumulated pressure of the pressure accumulator is 250Kgf/
cm ² , and the maximum filling pressure of the fuel cylinder is 200 Kgf/cm ² , so in the conventional system with one pressure accumulator system, the pressure difference between the pressure accumulators, which is a coefficient representing the capacity of the pressure accumulator, is 50 Kgf/cm ² . Become. On the other hand, in the present invention, the filling start pressure of the fuel cylinder is less than half the fuel pressure, that is,
When the pressure is 100Kgf/cm ² or less, the pressure of the variable pressure accumulator can be used up to 100Kgf/cm ² , so the pressure difference, which is the capacity coefficient, is 150Kgf/cm ² , which is three times the capacity. In the example, 1/3 of the total capacity of the accumulator is allocated to the high pressure accumulator and 2/3 to the variable pressure accumulator, so the capacity of the entire pressure accumulator is approximately 2 to 3 times that of a conventional pressure accumulator. have.

As a result, even if the filling frequency increases, the fuel cylinder can always be filled with sufficient pressure, and since this filling is automatically controlled by the controller, the filling time can also be shortened.

[Brief explanation of the drawing]

FIG. 1 is an embodiment of the present invention, and FIG. 2 is an explanatory diagram of a conventional filling method. 1...High pressure accumulator, 2...Variable pressure accumulator, 3...
...High pressure filling line, 4...Variable pressure filling line, 5
...Fuel filling line, 6...Fuel cylinder, 7...
Automobile, 8... High pressure switching valve, 9... Variable pressure switching valve, 10... Pressure gauge, 11... Controller.

Claims (1)

[Scope of Claim for Utility Model Registration] A pressure accumulator for storing compressed natural gas is divided into a high pressure pressure accumulator and a variable pressure pressure accumulator, and a high pressure filling line and a variable pressure filling line are connected from the high pressure pressure accumulator and the variable pressure pressure accumulator, respectively. A fuel filling line is provided which can be freely connected to the filling port of a fuel cylinder of an automobile by extending the line and merging it in the middle and extending the end of the line.The high pressure filling line is equipped with a high pressure switching valve, and the variable pressure filling line is equipped with a high pressure switching valve. In addition to installing a variable pressure switching valve, a pressure gauge was also attached to the fuel filling line. At the beginning of filling, the variable pressure switching valve is opened, and the high pressure switching valve is closed, and compressed natural gas is used as fuel for automobiles using the pressure of the variable pressure accumulator. When the cylinder is filled and the pressure gauge detects that the filling pressure has reached a certain level, the high pressure switching valve is opened, the variable pressure switching valve is closed, and the pressure in the fuel cylinder reaches the specified level by the pressure of the high pressure accumulator. A fuel supply device for a vehicle that uses compressed natural gas as fuel, characterized in that it is provided with a controller for controlling filling until pressure is reached.