JPH059628B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of the Invention The present invention relates to a hybrid Stirling engine in which a displacer piston is a free piston.

(b) Prior art In the conventional displacer type Stirling engine, do you link the power piston and the displacer piston using a link mechanism, or do you leave the displacer piston completely free and utilize the resonance of the entire system? It was either.

(c) Problems with the conventional technology In the former case, the crank chamber structure itself in which the link mechanism is built is complex, resulting in a large size and high cost, while the latter has the advantage of being low cost. Because it is a resonant system, the difference in motion phase angle between both pistons cannot be large, resulting in poor efficiency, and the inertia of the power piston is directly involved in engine vibration, so in order to counteract this, I would like to use a two-cylinder opposed type. However, it has the disadvantage that it can only be designed with a structure that has an extremely small output that is not affected much.

(d) Purpose of the invention To provide a compact, low-cost, high-efficiency, low-vibration system that incorporates the respective advantages of the so-called link system and free system, in which a free displacer piston is linked using the power piston's buffer space fluctuation pressure. Our goal is to provide a novel Sterling engine.

(E) Key Points of the Invention A cylinder is divided into two chambers, one chamber is divided into an expansion space and a buffer space by a displacer piston, and the other chamber is divided into a compression space and a buffer space by a power piston. By connecting the buffer spaces with a communication passage, when the power piston receives the power generated by the expansion and contraction of the working gas and transmits the output to the crankshaft, the buffer space of the displacer piston is connected to the buffer space of the power piston. By applying a fluctuating pressure of 100% through the communication passage, the free displacer piston, which works to alternately exchange the working gas between the expansion space and the compression space, can be operated reliably, and the power piston can be cranked. By connecting it to the shaft, it is possible to easily maintain the fluctuating pressure in the buffer space at a steady value, reduce the weight of the power piston, and suppress the transmission of vibrations to the outside.

(F) Embodiments of the Invention Figure 1 is a vertical cross-sectional view of a Stirling engine, in which 1 is a cylinder filled with a working gas such as helium, nitrogen, argon, air, etc., and 2 is a cylinder that is divided into two chambers 3 and 4. Insulating plates 5 and 6 are for each chamber 3,
4, a displacer piston and a power piston reciprocate in conjunction with each other as described later; 7, a heating pipe communicating with an expansion space 8 above the displacer piston; 9, a burner heat source 10 located above together with the heating pipe; 11 is a heat regenerator communicating with the other end of the heating pipe 7 and containing a porous wire mesh or sintered body, 12 is a cooler through which cooling water flows, and 13 is a compression space. 14 is an opening for inflow and outflow of the working gas, and 15 is a communication path connecting the buffer space 16 of one chamber 3 and the buffer space 17 of the other chamber 4.

Further, 18 is a crosshead portion formed integrally with the power piston 6, 19 is a bearing portion into which the crosshead portion is slidably fitted, 20 is a crosshead portion 18 and a cross pin 21 at one end, and a crankshaft 22 at the other end. 23 is the rotation locus of the crankshaft 22, 24, 25, 26 are seal rings, 27 is a spacing ring for scraping off lubricating oil, and 28 is a shell forming the crank chamber 29. be.

Next, the operation of the Stirling engine of the present invention will be explained based on FIG.

Isothermal expansion stroke (see figure A) The working gas is heated to approximately 600℃ by the burner heat source 10.
When the piston is heated to start expanding, the pressure is applied to the compression space 14 via the heating pipe 7, heat regenerator 11, and cooler 12, and pushes down the power piston 6. As the power piston 6 descends, the internal volume of the buffer space 17 decreases and its internal pressure increases. When this internal pressure begins to overcome the inertial force of the displacer piston 5 and the frictional force generated between the cylinder 1 and the wall, the pressure in this buffer space 17 increases to the communication passage 15.
joins the other buffer space 16 via
An attempt is made to relatively raise the displacer piston 5.

Equal Volume Heat Dissipation Stroke (See Figure B) As the power piston 6 further descends and the internal pressure of the buffer space 17 approaches the maximum, this internal pressure tries to further raise the displacer piston 5. This upward force is doubled by the inertial force of the piston 5. At this time, the frictional force and the like mentioned during the isothermal expansion stroke are acting in the blocking direction. As the displacer piston 5 rises, the working gas at a temperature of about 600°C moves from the expansion space 8 to the compression space 14, giving this heat to the heat regenerator 11, and generates heat of about 200°C.
The temperature drops to .degree. C. and is further cooled by a cooler 12.

Isothermal compression stroke (see Figure C) When the power piston 6 passes the bottom dead center due to its inertia force, the working gas that has entered the compression space 14 begins to contract due to cooling, causing the power piston 6 to rise. At the same time, compression begins due to the inertial force. When the power piston 6 rises, the buffer space 1
As the internal volume of 7 gradually expands, this internal pressure decreases. At the end of this stroke, the inertial force and frictional force of the displacer piston 5 act together, and at that point the displacer piston 5 reaches the top dead center of the cylinder 1, becomes stationary for a moment, and descends. Start.

Equal volume endothermic stroke (see the same figure) When the power piston 6 further rises, the internal pressure of the buffer space 17 becomes the minimum, and the working gas flows from the other buffer space 16 to the buffer space 17 via the communication path 15. The displacer piston 5 begins to move downward. Then, when the power piston 6 passes through the top dead center, the internal volume of the buffer space 17 begins to decrease, and the cycle shifts to the above-mentioned isothermal expansion stroke. At this time, the working gas moving from the compression space 14 to the expansion space 8 is heated by approximately 600% by the heat stored in the heat regenerator 11.
The temperature is raised endothermically to ℃.

The movement of the power piston 6, which reciprocates by repeating the above four cycles, is caused by the conrod 2.
0 is converted into a rotational motion of the crankshaft 22, and the output is taken out to the outside.

(g) Effects of the invention The Stirling engine of the present invention has a buffer space 1
6 and 17 are connected through a communication passage 15, and the displacer piston 5 is
Since the pistons 5 and 5 are linked together, the piston 5 is controlled with high precision even though it is free. In addition, the power piston 6 is connected to the crankshaft 2 under a constant stroke by a link mechanism such as a connecting rod 20.
2, the fluctuating pressure in the buffer space 17 can be easily maintained at a steady value, and if the internal volumes of the buffer spaces 16 and 17, the mass of the displacer piston 5, etc. are selected optimally, the display can be easily maintained. It is possible to optimally control various factors that directly affect performance and efficiency, such as the stroke of the servo piston 5 and the motion phase angle between both pistons 5 and 6. In addition, the two chambers 3 and 4 of both pistons 5 and 6 are heat-insulated and partitioned by the heat insulating plate 2, thereby achieving high efficiency.

Furthermore, by increasing the ratio (approximately equal to the mass ratio) between the inertia force of the power piston 6 and the inertia force of the displacer piston 5, the motion phase angle can be theoretically increased (the motion phase angle can be set to 90 degrees). For this reason, in the conventional all-free system, it was not possible to make the power piston 6 much lighter, but in the hybrid system of the present invention, the inertial mass due to the rotation of the crankshaft 22, etc. Since the power piston 6 can be designed by adding it to the inertial mass of the power piston 6, the power piston 6 itself can be made extremely lightweight. Therefore, when the heavy power piston 6 reciprocates up and down, the vibrations generated by the inertia force are transmitted to the outside unless it is canceled out by some method (for example, a two-cylinder opposed type as described above). For,
In the hybrid system of the present invention, the power piston 6
By balancing its own inertial force with the balance weight of the crankshaft 22, the transmission of vibration to the outside can be suppressed to an extremely low level.

Further, the hybrid type Stirling engine according to the present invention does not require a rod and link mechanism from the displacer service ton 5 compared to the conventional link type displacer type Stirling engine, so it is possible to reduce the weight and reduce power loss. In addition, since the crankshaft 22 can be placed directly below the cylinder 1, an extremely simple design is possible.
High efficiency, size and weight reduction can be achieved at low cost.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the Stirling engine of the present invention.
FIG. 2 is an operation stroke diagram of the Stirling engine of the present invention. 1... Cylinder, 3, 4... Two chambers, 5... Displacer piston, 6... Power piston,
8... Expansion space, 14... Compression space, 15... Communication path, 16, 17... Buffer space, 22...
crankshaft.

Claims (1)

[Claims] 1 Equipped with a cylinder filled with a working gas, a free displacer piston and a power piston that reciprocate within the cylinder under the external heating pressure of the working gas, and a crankshaft that extracts the reciprocating movement of the power piston as an output. In a free displacer type Stirling engine, the cylinder is divided into two chambers by a heat insulating plate, one chamber is used as an expansion space and a first buffer space by the displacer piston, and the other chamber is used as an expansion space and a first buffer space. A Stirling engine characterized in that a power piston partitions a compression space and a second buffer space, and the first buffer space and the second buffer space are connected by a communication passage.