WO1997001700A1

WO1997001700A1 - External combustion engine

Info

Publication number: WO1997001700A1
Application number: PCT/CH1996/000234
Authority: WO
Inventors: Pierre-Antoine Jeandupeux
Original assignee: Jeandupeux Pierre Antoine
Priority date: 1995-06-27
Filing date: 1996-06-21
Publication date: 1997-01-16
Also published as: AU5995096A

Abstract

An external combustion engine comprising a drive piston (1), a drive cylinder (2), a compression piston (10) and a compression cylinder (11). The drive piston (1) is connected to one crankshaft (7) and the compression piston (10) is connected to another crankshaft (16). The crankshafts are mechanically interconnected with a phase offset. The compression (11) and drive (2) cylinders are interconnected via intake pipes (20, 21) and expansion pipes (22, 23). Said pipes (20, 21, 22, 23) are connected to a regenerator (24). The intake (21) and expansion (22) pipes as well as the drive cylinder are heated by a heating device (25), and the expansion (23) and intake (20) pipes are cooled by respective cooling devices (27, 26). Intake (28) and expansion (29) valves are mounted on the compression cylinder.

Description

EXTERNAL COMBUSTION ENGINE

The present invention relates to an external combustion engine, and more particularly to a stationary external combustion engine with isentropic, isobaric and isochoric transformations.

The essential principle of external combustion engines is characterized by the fact that combustion takes place outside the cylinders and not inside the cylinders as is the case with internal combustion engines.

The best developments of internal combustion engines always have the same known drawbacks by the fact that very rapid explosions do not allow complete combustion to be obtained, which results in a loss of energy and in significant pollution and in the fact that the amount of heat released during the exhaust is not recycled.

The advantages of external combustion engines are that the necessary heat energy can be supplied by any heat source, by burning wood, by natural gas, and by electricity, for example, in addition of course fuel oil or other known fuels. Another advantage is that the combustion is continuous thereby reduce the amount of unburned ¹ and thus reduce pollution.

From a theoretical point of view, thermodynamic cycles based on the conservation of energy and on the concept of entropy, theoretical cycles aiming to approach a yield close to unity, have been known from the start the 1800s, for example the Carnot cycle, but most of these theoretical principles have so far been unable to be the subject of practical achievements, with the exception of the Stirling cycle for example.

The Stirling cycle has been the subject of numerous embodiments according to its particularity of recovery of the heat from the expansion fluids by a regenerator, but the known forms of execution of external combustion engines based on this principle have many disadvantages. . The cycle of Stirling has a displacement piston and a compression piston which, for example, are installed in opposition in two cylinder cylinders between which a regenerator is installed. The fluid between the cylinders therefore moves back and forth through the regenerator depending on the position of the pistons. The volumetric differences of the cylinder, which allow the engine to operate, are obtained by the differences in positions, during a cycle, of the engine piston and the compressor piston. The drawbacks are mainly constituted by the fact that the temperature of the regenerator varies as the heat transfer fluid passes, by the fact that the regenerator constitutes a resistance to transfers of the fluid which limits the number of cycles per unit of time, by the fact that the helium or hydrogen which must be used as fluids with this principle are either very expensive or dangerous, and consequently of these drawbacks by the fact that the engines produced according to the principle of the Stirling cycle provide a yield significantly lower compared to internal combustion engines. Despite this very limited yield from the known forms of execution based on the Stirling cycle, this principle continues to be the subject of much interest and research, but depending on the aforementioned drawbacks, industrial executions of wide circulation valid do not have not yet been completed.

The aims of the present invention therefore consist in remedying the aforementioned drawbacks and the aims are achieved according to the principle of the invention defined by claim 1.

The external combustion engine, according to the principle of the invention, comprises an engine piston and a compressor piston which are phase shifted and mechanically connected and which are each mounted in a cylinder. The two cylinders are interconnected by two pipes. An intake manifold allowing the fluid to pass from the cylinder of the compressor piston to the cylinder of the engine piston and a manifold allowing the expansion fluid to pass from the cylinder of the engine piston to the cylinder of the compressor piston. Two valves are mounted on the piston cylinder head compressor at the location of the two pipes so that, during the cycle, temporarily shut off either the intake manifold or the expansion manifold. The two pipes have shapes so that they intersect between the two cylinders, a crossing point where they are connected to a regenerator, which is heated by the fluid which comes out, hot, from the engine cylinder, and which is intended to heat the fluid, cold, which comes from the compressor cylinder.

The principle of the invention has many advantages. It makes it possible to guarantee a temperature stability of the regenerator which is very important in order to obtain an improvement in yield in a thermodynamic cycle. On the other hand, the fluid moves in pipes in a loop, which makes it easier to pass through and which makes it possible to envisage a significantly higher number of cycles per unit of time, thus making it possible to obtain an improvement in efficiency and power. The principle of the invention also allows operation with a fluid which is simply air, which eliminates the need to use expensive or dangerous gases.

The accompanying drawings illustrate schematically and by way of example the principles of the invention.

Figure 1 is a side sectional view of a pistonε, cylinderε, connecting rod and regenerator of an external combustion engine.

Figure 2 is a sectional view of the motor in a starting position of a cycle.

Figure 3 is a sectional view of the motor in a phase of the isentrope transformation cycle.

Figure 4 is a sectional view of the motor in an isobaric transformation phase.

Figure 5 is a sectional view of the motor in an isochoric transformation phase.

Figure 6 is a sectional view of the motor at the start of an isobaric transformation phase.

Figure 7 is a sectional view of the motor in an isochoric transformation phase.

Figure 8 is a graph of the engine cycle. Figure 9 is a sectional view of an embodiment of regenerator.

Referring firstly to FIG. 1, the external combustion engine comprises a driving piston 1 which is mounted in a driving cylinder 2. The driving piston 1 comprises a rod 3 whose end 4 is connected to one of the ends a connecting rod 5. The other end 6 of the connecting rod is connected to a crankshaft 7. A stick 9 is mounted at the end 4 of the rod 3. The stick 9 is slidably mounted in a guide cylinder 8. A compression pedestal 10 is mounted in a compressor cylinder 11. The compressor piston 10 comprises a rod 12 whose end 13 is connected to one end of a connecting rod 14. The other end 15 of the connecting rod is connected to a crankshaft 16. A stock 18 is mounted at the end 13 of the piston rod. The stick 18 is slidably mounted in a guide cylinder 19. The crankshafts 7 and 16 are arranged so that the pistons are out of phase with one another, for example by 90 °. The two crankshafts are mechanically connected together, for example by a notched runner. The crankshaft 16 includes an additional phase shift device 17 so that, in addition to the phase shift provided by the position of the two crankshafts, the two pistons move differently from each other during certain phases of the engine cycle. The engine cylinder 2 has an intake opening 31 and an expansion opening 30. The compressor cylinder 11 has an intake opening 32 and an expansion opening 33. An intake valve 28 cooperates with the intake opening 32 of the compressor cylinder. An expansion valve 29 cooperates with the expansion opening 33 of the compressor cylinder. The intake openings of the engine and compressor cylinders are connected to each other by intake pipes 20 and 21. The expansion openings of the engine and compressor cylinders are connected to each other by expansion pipes 22 and 23. The intake pipes intake 20 and 21 and expansion 22 and 23 are connected to a regenerator 24. The engine and compressor cylinders as well as the pipes are filled with a fluid 34, which may be air, for example. A heater 25 eεt disposed around the engine cylinder as well as εur a portion of the intake manifolds 21 and expansion 22, pipes which are mounted on the engine cylinder. The heating device can be fed or formed by any heating process, for example an oil or gas burner. A cooling device 26, for example a water cooling device, is mounted on the intake manifold 20 which is mounted on the compressor cylinder. A cooling device 27, for example a water cooling device, is mounted on the expansion pipe which is mounted on the compressor cylinder. The cooling devices can be constituted, for example, by water circulation pipes cooled by radiators.

According to the principle of the invention, the relatively cold fluid which is contained in the compressor cylinder, is compressed by the displacement of the compressor piston and is introduced into the intake manifold 20 as soon as the intake valve 28 opens. The fluid , cooled by the cooling device 26, is heated in the regenerator 24. The regenerator 24 is heated by the hot fluid which comes, via the expansion pipe, from the engine cylinder. The fluid is propelled into the engine cylinder in which it is heated by the heating device 25 which causes the transformation allowing one actuation of the engine piston. The return of the engine piston causes the fluid to pass through the expansion pipes, a fluid which cannot rain through the intake pipes, the intake valve being closed, and heats the regenerator, the purpose of which is to heat the fluid coming from the cylinder. compressor. In the final part of the expansion phase, the expansion valve 33 opens and the fluid, which can be cooled by the cooling device 27, returns to the compressor cylinder.

Figures 2 to 8 show the different phases of the external combustion engine cycle according to the principle of the invention.

Figure 2 shows the engine at the start of the cycle, with the compressor piston 10 in bottom dead center and the engine piston 1 in top dead center. The two valves 28 and 29 are closed. This phase of the cycle corresponds to point 35 of the graph in FIG. 8.

Figure 3 shows the motor in the isentrope transformation phase. The two valves 28 and 29 are closed. The compressor piston 10 moves and the fluid is compressed. The engine piston 1 remains in top dead center. This phase corresponds to the isentrope transformation carried out between points 35 and 36 in FIG. 8.

Figure 4 shows the engine in the isobaric phase. The compressor piston 10 continues to move. The intake valve 28 opens and the driving piston 1 remains in this starting phase of the isobaric transformation at top dead center. The expansion valve 29 is closed. This phase corresponds to point 36 in FIG. 8.

Figure 5 shows a phase of the isochore transformation. In this phase the two pistons 1 and 10 move together. The inlet valve 28 is open and the expansion valve 29 is closed. This phase corresponds to point 37 to 38 of Figure 8.

FIG. 6 shows a phase of the transformation at point 39 of FIG. 8 which corresponds to the transition from the isentropic transformation from 38 to 39 at the start of the isobaric transformation which corresponds to point 39. In this position, the driving piston 1 continues to move towards bottom dead center and the compressor piston 10 is in top dead center. At point 39, the expansion valve 29 opens and the intake valve 28 is closed.

Figure 7 shows the motor in the isochoric transformation phase. In this phase, which corresponds to point 40 to 35 of FIG. 8, the two pistons 1 and 10 move together, the compressor piston 10 towards bottom dead center and the engine piston 1 towards top dead center. The inlet valve 28 is closed and the expansion valve 29 is open.

During the cycle and with reference to FIGS. 2 to 8, from points 35 to 37, the engine piston remains in top dead center and the compressor piston moves towards bottom dead center. From points 37 to 38, the two pistons move together at the same speed, the engine piston towards bottom dead center and the compressor piston towards top dead center. From points 38 to 39, the compressor piston remains in top dead center and the engine piston moves towards bottom dead center. From points 40 to 35, the two pistons move together, the engine piston towards top dead center and the compressor piston towards bottom dead center. The intake valve opens from point 36 to point 38. The expansion valve opens from point 39 to point 35.

With reference to FIG. 8, the curves 41 and 42 correspond to the known curves obtained by a conventional Stirling principle.

With reference to the graph in FIG. 8, it can be seen that the surface of the cycle obtained by the principle of the invention is smaller than the theoretical surface obtained with a Stirling principle. The Stirling principle indeed provides isothermal transformations from points 35 to 37, and points 38 to 40, but these isothermal transformations are extremely difficult to carry out in a practical manner. The object of the present invention therefore consists in obtaining a practically easily achievable cycle, which is obtained by modifying the isothermal transformations, so that the isothermal transformation is replaced by an isentropic transformation and an isobaric transformation.

According to the principle of the invention, the advantages are obtained by the particularity of the displacement of the pistons and of the valves described according to FIGS. 3 to 8, by the connection of the two cylinders which are connected together by intake and expansion pipes, and by the fact that the intake and expansion pipes are connected to a regenerator. This crossing of the pipes makes it possible to obtain a temperature of the regenerator which is relatively constant because it is in equilibrium between the hot temperature of the expansion fluid and the cold temperature of the intake fluid. This embodiment eliminates the disadvantages of the Stirling principle with which the regenerator changes temperature up or down depending on the phase of the cycle.

Figure 9 shows an embodiment of a regenerator which consists of plates which are stacked one on the other. other. A plate 43 mounted on a plate 45 which is mounted at 90 ° relative to the plate 43. And plates 43 'and 45', 43 '' and 45 '' and so on. The plates 43 and 45 consist of a plate which is curved at its ends so as to constitute an opening 44 for the plate 43 and 46 for the plate 45. On the embodiment shown in FIG. 9, the intake manifolds 21 and 20 are connected to the regenerator and the intake fluid can flow through the openings 46, 46 'and 46''and through the other openings according to the number of plates which are mounted on each other. The expansion fluid can flow through the openings 44, 44 'and 44''which are arranged at 90 ° relative to the intake openings.

The number of plates constituting the regenerator can vary depending on the size of the engine and the amount of fluid that must pass through the regenerator.

The embodiment shown in Figures 1 to 7 shows an engine having cylinders arranged in opposition on the same axis. The cylinders can also be arranged in a V at any angle.

Claims

1. External combustion engine comprising a piston (1) and a cylinder (2) engine and a piston (10) and a compressor cylinder (11), and comprising a fluid which may be air and which is contained in the cylinders, fluid which is transferred through a regenerator, during the engine cycle, from the engine cylinder to the compressor cylinder by being heated or cooled by heating and cooling devices and by a regenerator, characterized by the fact that intake manifolds (20 and 21) are respectively connected to inlet (28) and expansion (31) openings which are formed respectively in the compressor cylinder (11) and in the engine cylinder (2) and that expansion pipes (22 and 23) are respectively connected to expansion (30) and intake (33) openings which are respectively formed in the engine cylinder and in the compressor cylinder, so that the fluid contained in the cylinders can pass from one cylinder to another εelon the phase of the engine cycle, pipes which are connected to a regenerator (24), and by the fact that an expansion valve (29) is disposed at the expansion opening ( 33) formed in the compressor cylinder and that an intake valve is arranged at the intake opening (28) formed in the compressor cylinder.

2. External combustion engine according to claim 1, characterized in that the driving piston and the compressor piston are connected to crankshafts which are mechanically connected to each other and which are arranged and formed so that the pistons are out of phase between them during certain phases of the engine cycle.

3. External combustion engine according to claim 1, characterized in that during the isentropic and isobaric inlet transformation phases, the engine piston remains in the top dead center position and the compressor piston moves towards from bottom dead center to top dead center.

4. External combustion engine according to claim 1, characterized in that during the iεentrope and isobaric expansion tranεformation the compressor piston remains in top dead center and the engine piston moves towards bottom dead center.

5. External combustion engine according to claim 1, characterized in that during the two isochoric transformations the two pistons move together at the same speed, in the first isochoric transformation the compressor piston towards top dead center and the engine piston towards the bottom dead center and vice versa in the second isochore transformation.

6. External combustion engine according to claim 1, characterized in that the intake manifold (20) which is connected to the intake opening which is formed in the compressor cylinder, is cooled by a cooling device ( 26) and by the fact that the expansion tubing which is connected to the expansion opening which is formed in the compressor cylinder is cooled by a cooling device (27).

7. External combustion engine according to claim 1, characterized in that the intake (21) and expansion (22) pipes which are connected, respectively to the intake (31) and expansion (30) openings which are made in the engine cylinder, and the engine cylinder is heated by a heater (25).

8. External combustion engine according to claim 1, characterized in that the intake valve (28) opens at the end of the isentropic intake transformation and closes at the start of the isentropic expansion transformation, and by the fact that the expansion valve (29) opens at the end of the isentropic transformation of relaxation and closes at the beginning of the isentropic transformation of admission.

9. external combustion engine according to claim 1, characterized in that the regenerator (24) consists of plates which are mounted on each other and which are arranged so that each plate is arranged at 90 ° relative to the upper or lower plate, and by the fact that each plate is folded at its ends so as to constitute an opening for passage of the fluid.

10. External combustion engine according to claims 1 and 9, characterized in that the intake and expansion pipes are mounted on the regenerator, at 90 ° between them so that they are connected respectively with the openings of one plate out of two depending on the layout of each plate.