JPH0468578B2 - - Google Patents

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention relates to an air pressure control device for use in a low-pressure environmental test chamber for self-propelled vehicles, particularly for conducting low-pressure environmental test chambers assuming that automobiles run at high altitudes. .

<Prior Art and Its Disadvantages> Various environmental tests assuming that a car will be driven at high altitudes are conducted with the car housed in a low-pressure environmental test chamber.

FIG. 2 shows an air pressure control device for setting the air pressure in the low-pressure environmental test chamber to a desired low air pressure.

In the same figure, outside air is drawn by an air supply blower 25 from an air supply port 24 at the tip of a ventilation pipe 23 into a low-pressure environmental test chamber 22 in which a car 21 is accommodated, passes through a flow rate control valve 26, and passes through a throttle 27. Air is supplied through the The opening degree of this flow rate control valve 26 is adjusted by the output from a flow meter 28 connected in parallel to the throttle 27.

Further, an intake port 30 provided at the tip of the exhaust vent pipe 29 is arranged near the exhaust port of the exhaust pipe 21a of the automobile 21; The exhaust gas and the air in the test chamber 22 are drawn by a pressure reducing blower 32 via a pressure regulating valve 31, and are exhausted through a silencer 33. The valve opening degree of this pressure regulating valve 31 is
It is adjusted in response to the output of a pressure sensor 34 provided within the pressure sensor 2. In addition, a pressure regulating valve 31 and a pressure reducing blower 32
A vacuum breaker 35 is provided between them, and is activated when the atmospheric pressure inside the test chamber 22 is reduced to a predetermined low atmospheric pressure or less.

By the way, in such a conventional air pressure control device,
Since it is necessary to exhaust the exhaust gas from the automobile 21 to the outside, an inlet 30 is opened near the exhaust port of the exhaust pipe 21a, and the exhaust gas and the air in the test chamber 22 are exhausted only through this inlet 30. The indoor pressure is set to the desired low pressure.

Therefore, in the conventional method, there is a problem that the back pressure of the pressure reducing blower 32 affects the exhaust port of the exhaust pipe 21a. Furthermore, when the exhaust gas is being exhausted from the exhaust pipe 21a, the exhaust gas is sucked in from the intake port 30, reducing the intake of indoor air.
Particularly when the engine speed changes rapidly, the air pressure at the exhaust port of the exhaust pipe 21a does not match the air pressure in the room.

As a result, the exhaust gas is exhausted from the exhaust port of the exhaust pipe 21a to an atmospheric pressure different from the atmospheric pressure of the test chamber 22, resulting in a problem that the test cannot be performed in a natural environment.

Furthermore, in the past, all the air passing through the ventilation pipe 29 passed through the pressure regulating valve 31, so the pressure regulating valve 31 had to be large in size, making it difficult to control the air pressure with high precision. .

<Object of the present invention> The object of the present invention is to prevent the back pressure of the depressurizing blower from affecting the exhaust pipe port of an automobile, and to maintain the atmospheric pressure at the exhaust pipe port regardless of the engine speed of the automobile. The purpose is to control the atmospheric pressure in the test chamber so that it is always the same.

Another objective is to improve the accuracy of air pressure control within the test chamber.

<Structure of the present invention> In order to achieve the above object, the air pressure control device for a low-pressure environmental test chamber of a self-propelled vehicle of the present invention is provided with an air supply means for supplying outside air into the low-pressure environmental test chamber, The suction port at one end of the first ventilation pipe is arranged near the exhaust port of the exhaust pipe of an automobile housed in a low-pressure environmental test chamber, and the other end of the first ventilation pipe is connected to the main ventilation pipe. The suction port at one end of the second vent pipe is opened into the low-pressure environment test chamber, the other end of this second vent pipe is connected to the main vent pipe through a pressure regulating valve, and the second end of the second vent pipe is connected to the main vent pipe in the middle of the main vent pipe. Equipped with a variable number of decompression blowers,
A silencer is provided in the main ventilation pipe on the discharge side of the pressure reduction blower, and the silencer is opened to the outside air, and a silencer is provided on the outside air intake side at a location in the main ventilation pipe that becomes the suction side of the pressure reduction blower. At the same time, the other end of the branch pipe is connected to a branch pipe having a pressure regulating valve in the middle.

<Example> FIG. 1 is a block diagram of a barometric pressure control device for a low-pressure environmental test chamber according to the present invention, and FIG. 2 is a block diagram of a conventional barometric pressure control device.

Next, an embodiment of the present invention will be explained using a specific example shown in the drawings.

In FIG. 1, a low-pressure environmental test chamber 2 in which a self-propelled vehicle, such as a car 1, is housed on a test stand 19 is filled with outside air drawn by an air supply blower 5 from an air supply port 4 at the tip of a ventilation pipe 3. The air is supplied through the flow control valve 6 and through the throttle 7. The opening degree of this flow rate control valve 6 is adjusted by the output from a flow meter 8 connected in parallel to the throttle 7.

This air supply mechanism supplies a predetermined amount of outside air into the test chamber 2 during depressurization, and also quickly changes the pressure inside the test chamber 2, which is set at a low pressure below atmospheric pressure, to a pressure closer to atmospheric pressure. It will be operated when resetting to .

Further, an intake port 10 provided at the tip of an exhaust ventilation pipe 9a is arranged near the exhaust port of the exhaust pipe 1a of the automobile 1, and this ventilation pipe 9a is connected to the main ventilation pipe 9.
It is connected to the.

Further, a suction port 11 provided at the tip of the exhaust vent pipe 9b opens into the test chamber 2, and a pressure regulating valve 17 is provided in the middle of the vent pipe 9b. The ventilation pipe 9b is connected to the main ventilation pipe 9.

In the main ventilation pipe 9, a variable rotation speed electric motor 12 is provided.
A depressurizing blower 12 driven by Air inside the test chamber 2 is sucked through the test chamber 11. Decompression blower 12
The air sucked in is exhausted to the outside of the test chamber 2 through the silencer 13.

Further, a branch pipe 14 is connected to the main ventilation pipe 9 on the suction side of a pressure reducing blower 12.
A pressure regulating valve 15 is provided in the middle of 4. A silencer 16 for taking in outside air, which is open to the atmosphere, is provided at the tip of this branch pipe 14.

The valve opening degrees of the pressure regulating valves 15 and 17 and the rotation speed of the variable rotation speed motor 12a are controlled independently via a control unit 20 such as a microcomputer in response to the output of a pressure sensor 18 provided in the test chamber 2. are adjusted respectively.

<Operation and Effect> In the above-mentioned atmospheric pressure control device configured in this way,
The air in the test chamber 2 is sucked in from both the suction port 10 and the suction port 11, and the air is not forced to be sucked in from the exhaust port of the exhaust pipe 1a, so that the engine of the automobile 1 is not affected by the back pressure of the decompression blower 12. I have nothing to give. Also, the engine speed of car 1 changes,
Even if there is a sudden increase or decrease in the amount of exhaust gas, the valve opening of the pressure regulating valve 17 is adjusted by the control signal A from the control unit 20 that monitors the output of the pressure sensor 18, and the amount of gas in the test chamber 2 from the suction port 11 is adjusted. Since the intake amount of air is controlled, there is no pressure fluctuation at the exhaust port of the exhaust pipe 1a, and the pressure at the exhaust port and the pressure inside the test chamber 2 can always be controlled to be the same. This allows testing to be conducted under natural environmental conditions.

In addition, in the above-mentioned atmospheric pressure control device, when setting the atmospheric pressure in the test chamber 2, a control signal B from the control section 20 to which the detection output of the pressure sensor 18 that detects the atmospheric pressure in the test chamber 2 is supplied is used to control the pressure reduction. A control unit 2 that controls the rotation speed of the variable electric motor 12a of the blower 12 and outputs it independently of the control signal B.
Since the outside air intake amount is controlled by adjusting the pressure regulating valve 15 using the control signal C from 0, compared to the conventional method using only the pressure regulating valve installed in the main ventilation pipe,
Improves accuracy of air pressure control. Here, when the set pressure is closer to atmospheric pressure, the rotation speed of the variable electric motor 12a is controlled to be lower, and the pressure regulating valve 1
The valve opening degree of No. 5 is controlled to be large. In addition, since the pressure regulating valve is not provided in the main ventilation pipe as in the past, but is provided in the branch pipe 14, the amount of air passing through the pressure regulating valve 15 is extremely small. can use things. Therefore, the valve diameter of the pressure regulating valve 15 becomes smaller, and the control of the atmospheric pressure inside the test chamber 2 is further improved. In addition, unlike the conventional case in which only the air in the test room with high suction resistance is sucked by the decompression blower, part of the atmosphere is drawn from the atmospheric side with low suction resistance through the branch pipe 14 by the depressurization blower 12. Because of the suction, the shaft power of the pressure reduction blower 12 becomes smaller as the set pressure in the test chamber 2 approaches atmospheric pressure, and the noise emitted from the pressure reduction blower 12 is accordingly reduced.

[Brief explanation of the drawing]

FIG. 1 shows a configuration diagram of an air pressure control device for a low-pressure environmental test chamber according to the present invention, and FIG. 2 shows a configuration diagram of a conventional air pressure control device. The names of the parts indicated by the symbols in the figure are as follows. 1...Automobile, 2...Testing room, 3...Vent pipe, 4...
Air supply port, 5... Blower, 6... Flow rate control valve, 7... Throttle, 8... Flow meter, 9a... Ventilation pipe, 10... Suction port,
DESCRIPTION OF SYMBOLS 11... Exhaust port, 12... Blower, 13... Silencer, 14... Branch pipe, 15... Pressure regulating valve, 16... Silencer, 17... Pressure regulating valve, 18... Pressure sensor, 19... Test bench, 20... Control part.

Claims (1)

[Claims] 1. Air supply means for supplying outside air into the low-pressure environmental test chamber is provided, and the inlet at one end of the first ventilation pipe is connected to the exhaust pipe of a self-propelled vehicle housed in the low-pressure environmental test chamber. The other end of the first ventilation pipe is connected to the main ventilation pipe, and the suction port at one end of the second ventilation pipe is opened into the low-pressure environmental test chamber. The other end of the trachea is connected to the main vent pipe through a pressure regulating valve, a pressure reducing blower with a variable rotation speed is provided in the middle of the main vent pipe, and a silencer is installed in the main vent pipe on the discharge side of the pressure reducing blower. The silencer is opened to the outside air, and the other end of the branch pipe, which has a silencer on the outside air intake side and a pressure regulating valve in the middle, is connected to the main ventilation pipe at a point on the suction side of the pressure reducing blower. Air pressure control device for the connected low-pressure environmental test chamber for self-propelled vehicles. 2. The air pressure control device for a low-pressure environment test chamber for a self-propelled vehicle according to item 1, wherein the valve opening degree of the pressure regulating valve is controlled in response to an output from a pressure sensor disposed within the low-pressure environment test chamber. 3. The air supply means has an air supply blower, a flow rate control valve, and a throttle connected in series in the middle of an air supply pipe whose one end serves as an air supply port and is open to the outside air, and the other end is open to the low-pressure environmental test chamber. 2. The air pressure control device for a low-pressure environment test chamber for a self-propelled vehicle according to claim 1, wherein the valve opening degree of the flow rate regulating valve is controlled in response to the output of a flow meter provided in parallel with the throttle.