JPH0331909B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a working gas pressure control device for a Stirling engine that includes an unload valve that uses working gas in a discharge line of a compressor for opening and closing.

BACKGROUND OF THE INVENTION The output of a Stirling engine, which is an external combustion engine, is determined by the pressure within a working space filled with working gas. For example, when increasing the output of a Stirling engine, the working gas pressure in the working space is increased. A typical conventional example of such a Stirling engine output control device is shown in FIG. 3 (see Japanese Patent Laid-Open No. 46-23534). The working space 1 of the Stirling engine is connected via a check valve 2 to a compressor 3 by a maximum cycle pressure line 4 and a line 15 . The line 4 and line 15 are connected through a pressure reducing valve 5. or,
The working space 1 is connected to the compressor 3 by a minimum cycle pressure line 7 and a line 16 via a check valve 6 . The line 7 and line 16 are connected to the pressure increase valve 8.
Connect with. 9 indicates a high pressure tank.

The downstream side of the pressure increase valve 8 is connected to a feedback piston cylinder 10, and the piston within the cylinder 10 is connected via a rod to the end of an accelerator lever 11 which serves as an operating lever. accelerator lever 11
are opposed to the valve stems 12, 13 of the increase/decrease valves 8, 5.
The feedback piston cylinder 10 has a piston that moves according to the pressure of the lowest cycle pressure line 7.
It functions to displace the position of the fulcrum 14 of the accelerator lever 11.

When increasing the output of the Stirling engine, the accelerator lever 11 is pushed to the left to open the pressure increase valve 8, and high-pressure working gas is supplied from the compressor 3 or tank 9 to the working space 1. Further, when lowering the output of the Stirling engine, the accelerator lever 11 is pushed to the right to open the pressure reducing valve 5, and the pressure in the working space 1 is released to the compressor 3 side to reduce the pressure. When the increase/decrease in output enters a stable range (predetermined value) during steady operation, the pressure increase/decrease valves 8 and 5 close due to the displacement of the movable fulcrum 14.

By the way, during steady operation, the compressor 3
Since working gas is sucked in from line 5 and high-pressure working gas is discharged to line 16, the pressure difference between both lines 15 and 16 is large, that is, a large pressure change occurs, and the work of the compressor 3 is large, causing the compressor to There are many obstacles to this. Therefore, it has been proposed to provide a bypass line 17 having an unload valve 18 between both lines 15 and 16. In this means, during steady operation of the Stirling engine (reduction valve 5 is closed), valve 18 is manually opened to make the working gas pressures in both lines 15 and 16 substantially the same. As a result, during the steady operation, the working gas flows from line 16 to line 1.
7 and returns to the compressor 3 via line 15, and since the compressor 3 does little compression work, the aforementioned disturbance to the compressor 3 can be eliminated.
However, when entering steady operation, the valve 1 must be manually operated.
8 and then manually close the valve 18 during deceleration, which is cumbersome and undesirable in view of damage to the compressor 3 if this is neglected.

Therefore, the pressure reducing valve 5 is left in place, and a solenoid valve 18 is arranged in the line 17.
It is possible to close 8.

Problems to be Solved by the Invention The use of a solenoid valve that closes in response to the opening signal of the pressure reducing valve requires a large valve hole to reduce the flow resistance of the working gas, and the valve member is exposed to high pressure gas. Therefore, it requires a large suction force. For this reason,
The electromagnetic valve is large and requires a large amount of electric power, and if a Stirling engine is used in the output section of the vehicle, a large capacity battery or generator must be installed, which adversely affects the running performance of the vehicle.

Therefore, the present invention aims to solve the above-mentioned problems.

Means for Solving the Problems In order to solve the above-mentioned problems, the present invention has the following features:
In order to use the pressure in the discharge side line to control the opening and closing of the unload valve, a three-way solenoid valve is placed between the suction and discharge lines, and when the pressure reducing valve is closed, the unload valve is opened using the discharge side line pressure. A technical means is used to apply discharge side line pressure in the direction of opening the pressure reducing valve and closing the unloading valve.

Function Since the unload valve is opened and closed using the discharge side line pressure, the unload valve can be made large and no auxiliary equipment is required. Since the three-way electromagnetic device only switches the flow direction of the discharge line pressure, it may be small.

Embodiment FIG. 1 shows an embodiment of the present invention, in which the same parts as in the example of FIG. 3 are denoted by the same reference numerals, and their explanation will be omitted. In the example shown in FIG.
4 is omitted.

Between the suction and discharge side lines 15 and 16 of the compressor 3,
A three-way solenoid valve 19 is arranged, and its common port 19a
is connected to the unload valve 20, the normally open port 19b is connected to the discharge side line 16, and the normally closed port 19c is connected to the suction side line 15, and the ports 19a and 19b are communicated together with the closing signal of the pressure reducing valve 5.

An unload valve 20 is disposed on a bypass line 17 that connects the suction and discharge side lines 15 and 16. An example of the unload valve 20 is shown in FIG. The housing 21 of the unload valve 20 has a stepped bore, and the upper and lower parts thereof are covered with covers 22 and 23. A piston 24 is disposed in the upper chamber, which is divided into a chamber 25 communicating with the common port 19a and a chamber 26 communicating with the suction side line 15.
The lower chamber 27 communicates with the discharge side line 16 , and the communication between this chamber 27 and the suction side line 15 and the chamber 26 is controlled by a valve member 29 that is biased by a spring 28 . Valve member 29 is connected to piston 24 via stem 30.

When the pressure reducing valve 5 is closed, the unload valve 20
The piston 24 of is connected via the common port 19a,
It receives pressure from the discharge side line 16 and moves downward against the biasing force of the spring 28, pushing down the valve member 29. Therefore, both lines 15 and 16 are brought into communication. On the other hand, when the pressure reducing valve 5 opens, the normally closed port 19c becomes open, and the port 19a becomes the port 19c.
The pressure of the suction side line 15 is communicated with the port 19.
c and the line 15 to the chamber 26, and the opposing pair of chambers 25, 26 are brought to the same pressure via the piston 24. Therefore, the biasing force of the spring 28 causes the valve member 29 to close. As a result, there is no bypass flow between the lines 15, 16.

Effects In the present invention, since the high pressure gas on the cylinder side is used to open and close the unload valve, the opening and closing operation of the unload valve becomes reliable.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an example of the present invention, FIG. 2 is a sectional view of an unload valve, and FIG. 3 is an explanatory diagram of a conventional example. In the diagram: 1... working space, 3... compressor, 4...
Highest cycle pressure line, 5: pressure reducing valve, 7: lowest cycle pressure line, 8: pressure increasing valve, 19: three-way solenoid valve, 20: unloading valve.

Claims (1)

[Claims] 1. A pressure increasing valve provided in the lowest cycle pressure line connected to the working space via a one-way valve, a pressure reducing valve provided in the highest cycle pressure line connected via the one-way valve during the operation, and A device for controlling opening and closing, a compressor having a suction and discharge side line connected to the both cycle pressure lines via a one-way valve, an unload valve disposed in a circuit that short-circuits the suction and discharge lines of the compressor, and a constant A working gas pressure control device for a Stirling engine having a three-way solenoid valve having an open port connected to the discharge side line, a normally closed port connected to the highest cycle pressure line, and a common port connected to the working chamber of an unload valve.