JPS60198361A - Output controller for stirling engine - Google Patents

Abstract

PURPOSE:To reduce gas pressure against a compressor and thereby aim at the prolongation of its service life, by installing a check valve in position between a decompression valve of a Stirling engine and a suction valve of the compressor as well as between a discharge valve of the compressor and a tank, respectively, and also installing a bypass valve interposingly between these suction and discharge valves of the compressor. CONSTITUTION:A stirling engine pushes an accelerator lever 11 to the left, making a booster valve 8 open, and feeds high pressure working gas to a working space from a compressor 3 or a tank 9 whereby it aims at an output increase, while it pushes the accelerator lever 11 to the right, making a decompression valve 5 open, and pressure inside the working space is removed whereby it aims at a output decrease, respectively. In this case, each of check valves 23 and 24 are installed interposingly between the decompression valve 5 and a compressor suction valve 21 as well as between a compressor discharge valve 22 and the tank 9. And, the upstream side of the check valve 23 is interconnected to a working chamber 32 of a bypass valve 30 with a pipe line 26, and simultaneously the upstream side of the check valve 24 is interconnected to one side valve chest 33 of the bypass valve 30 with a pipe line 28 while the downstream side of a check valve 22 to the other side valve chest 34 by a pipe line 28', respectively.

Description

[Detailed description of the invention] [Subject of the invention and its field of application] The present invention relates to an output control device for a Stirling engine, and a pressure reducing valve and a pressure increasing valve provided in the maximum and minimum cycle pressure lines of the Stirling engine are controlled by an accelerator lever. It is used in the output control device of a Stirling engine that is controlled to open and close and has a compressor installed downstream of a pressure reducing valve.

[Prior art]

The output of a Stirling engine, which is a conventional 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. The working space 1 of the Stirling engine is compressed t! via the check valve 2. ! 3 by a maximum cycle pressure line 4. The line 4 has a pressure reducing valve 5. The working space 1 is also connected to the compressor 3 by a minimum cycle pressure line 7 via a check valve 6 . The line 7 has a pressure increase valve 8 . 9 indicates a high pressure tank.

The downstream side of the pressure increase valve 8 is connected to the feedback piston cylinder 1.
0, and the piston in the cylinder 10 is connected to the end of the accelerator lever 11 via a rod. The accelerator lever 11 is connected to the pressure increase valve 8. It faces the valve stems 12 and 13 of the pressure reducing valve 5. The feedback piston cylinder 10 has a piston that moves according to the pressure of the lowest cycle pressure line 7, and 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.

In the output control device for the Stirling engine of the above type, when the pressure reducing valve 5 is closed, that is, when the engine is in steady operation, there is no working gas flowing into the compressor 3, so the pressure in front of the suction valve of the compressor 3 is , decreases to an extremely low value depending on the maximum compression ratio of the compressor 3. Compressor 30 operating space pressure varies between very low pressure and high pressure within tank 9. During steady engine operation, this large pressure change can cause damage to the valve mechanism and compressor.
This results in noise problems and loss of engine power.

As a way to solve this problem,
In this issue, a device as shown in Figure 2 was proposed, in which a bypass valve 1 was installed between the suction valve and discharge valve of the compressor without using a pressure reducing valve.
Bypass valve 5 is provided, and when reducing engine output, bypass valve 1 is provided.
5 is closed and the working gas is returned to the tank 9, and during steady operation, the bypass valve 15 is opened to prevent pressure changes from occurring in the working bypass of the compressor 3.

[Problems with conventional technology]

However, in the output control device, the bypass valve is open during steady operation of the engine, and the gas pressure in the working space of the compressor is equal to the maximum cycle pressure, so a very high gas pressure is acting on the compressor. The large load applied to moving parts such as piston rings and bearings caused severe friction loss and wear, resulting in problems such as a reduction in engine output and durability.

[Technical issues]

In view of the above points, the present invention reduces the gas pressure applied to the working space of the compressor during steady engine operation, eliminates pressure changes, reduces compressor friction loss, and prevents a drop in engine output. The technical challenge is to extend the life of the compressor.

[Technical means]

The technical measures taken to solve the above technical problems are:
A check valve 23 is installed between the pressure reducing valve 5 and the suction valve 21 of the compressor 3, and a check valve 2 is installed between the discharge valve 22 of the compressor 3 and the tank 90.
4, and a bypass valve 30 that opens and closes depending on the gas pressure between the pressure reducing valve 5 and the check valve 23 is provided between the suction valve 21 and the discharge valve 22 of the compressor 3.

[Effect of technical means]

The above technical means works as follows. That is, when reducing the engine output, when the pressure reducing valve 5 is opened, the gas pressure between the pressure reducing valve 5 and the check valve 23 increases, the bypass valve 30 controlled by the gas pressure is closed, and the pressure reducing valve 5 is opened. The passing working gas is compressed by the compressor 3 and stored in the tank 9. Once the engine is in steady operation, the pressure reducing valve 5
is closed, the gas pressure between the pressure reducing valve 5 and the check valve 23 is reduced, and the bypass valve 30 is opened. At this time, the working gas pressure acting in the working space of the compressor 3 is low and there is no pressure change.

[Special effects caused by this invention]

The present invention produces the following unique effects. That is, it is also possible to provide a bypass valve between the suction valve and the discharge valve of the compressor 3 of the conventional device shown in FIG. 1, and to open and close the bypass valve in conjunction with the pressure reducing valve 5. If the operations of the bypass valve 5 and the bypass valve do not match, a problem arises in that even if the pressure reducing valve 5 opens, the bypass valve remains open and the pressure cannot be reduced. In contrast, in the present invention, the bypass valve is actuated by the gas pressure between the pressure reducing valve and the suction valve of the compressor 3, so the bypass valve operates reliably, has a simple mechanism, and is inexpensive. .

Further, during steady operation of the engine, the gas pressure acting in the operating space of the compressor 3 is low (and there is no pressure change), so the friction loss of the compressor 3 can be reduced and the durability can be improved.

〔Example〕

Hereinafter, an embodiment showing an example of the above-mentioned technical means will be described with reference to FIG. Note that the parts corresponding to the configuration shown in FIG. 1 are denoted by the same reference numerals, and the explanation thereof will be omitted. A first check valve 23 is provided between the pressure reducing valve 5 and the suction valve of the compression ta3,
A conduit 25 between the check valve 23 and the pressure reducing valve 5 and the working chamber 23 of the bypass valve 30 are communicated through a conduit 26, and a second check valve is provided between the discharge valve 22 of the compressor 3 and the tank 9. Established 24,
a conduit 27 between the check valve 29 and the discharge valve 22 of the compressor 3;
and one valve chamber of the bypass valve 30 by a conduit 28, and further a conduit 29 between the check valve 23 and the suction valve 21 of the compressor 3 and the other valve chamber 34 of the bypass valve 30 by a conduit 28. When the pressure reducing valve 5 opens, the bypass valve 30 closes, and when the pressure reducing valve 5 closes, the bypass valve 30 opens, and the suction valve 21 and discharge valve 22 of the compressor 3 are short-circuited. . The bypass valve 30 has a valve body 31 as shown in FIG.
A piston 34 is provided integrally with the valve body 35 and is slidably provided within the piston 34, and a sealing material 36 is provided on the piston 34 to seal between the working chamber 32 above the piston 34 and the atmospheric chamber 37 below. A spring 38 is provided in the atmospheric chamber 37 to move the piston 34 upward, and the valve chamber 3
A sealing material 39 is provided between the air chamber 3 and the atmospheric chamber 37. The valve seat 40 is made of rubber, plastic, Teflon, etc., and has two valve chambers in order to provide a seal with the valve body 35.
Divide into two rooms.

[Modification example]

In FIG. 5, the gas pressure switch 41 between the pressure reducing valve 5 and the check valve 23 detects the pressure and activates the electromagnetic valve 42, and it is possible to obtain the above-mentioned effect in this embodiment as well. .

[Brief explanation of the drawing]

1 and 2 are explanatory diagrams showing a conventional output control device for a Stirling engine, FIG. 3 is an explanatory diagram showing an output control device according to an embodiment of the present invention, and FIG. 4 is an explanatory diagram showing a bypass valve according to the present invention. FIG. 5 is an explanatory diagram showing a specific example of the present invention, and FIG. 5 is an explanatory diagram showing a modified embodiment of the present invention. 1... Working space, 3... Compressor, 5... Pressure reducing valve,
8... Pressure increase valve, 21... Suction valve, 22... Discharge valve, 23... First check valve, 24... Second check valve,
25... Conduit, 30... Bypass valve Patent applicant 1 Ireshi Kozuenara Co., Ltd. Representative Reio Nakai Figure 1

Claims (1)

[Claims] In an output control device for a Stirling engine that controls engine output by controlling the pressure of working gas in a working space using a pressure increasing valve and a compressor, a first
A second check valve is installed between the compressor discharge valve and the tank storing the working gas, and a second check valve is installed between the compressor suction valve and the discharge valve to bypass the compressor. a controllable bypass valve is provided, the bypass valve is controlled to open and close by the gas pressure in the conduit between the pressure reducing valve and the first check valve, and is substantially open when the pressure reducing valve is closed; An output control device for a Stirling engine that closes when the pressure reducing valve is open.