HOW A STIRLING GAMMA ENGINE WORKS?
Without regenerator
Phase 1-2:At the beginning of this phase, the displacer piston starts in its lowest point and the power piston stays in its corresponding height, considering a difference of 90 degrees in the angle of rotation of the crankshaft between the elbows of the two pistons. When applying a heat source at the bottom of the cylinder of the displacer piston, the air in the system begins to heat up. At this point, it's essential the intervention of the wheel's inertia. At the end of the phase 1 - 2, the inertia that rotates the crankshaft, makes the displacer piston start rising and the power piston get to the bottom. The rise of the displacer piston contributes to let a greater amount of air to pass to the hot focus of the cylinder, so that more air can be easily heated. During this process, the power piston goes down as the gas will not offer any resistance.
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Phase 2-3:At the beginning of this phase, the power piston is at its lowest point. Meanwhile, the displacer piston reaches its summit, making nearly all the air of the system occupy the hot side of the cylinder of the displacer piston. This gas gets warmer and its volume increases. The expansion of the gas makes the power piston rise through its cylinder due to the increased pressure in the system. This increase of pressure is responsible of performing the work in the engine, so it is key to make the engine work. If the system does not suffer an noticeable increase of pressure, the piston doesn't rise and the engine is unable to perform any work by himself.
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Phase 3-4:During this phase, the power piston reaches its summit. The arrangement of the crankshaft elbows forces the displacer piston to move down when the power piston rises. Here, some of the air goes to the cold focus due to the increase of space in this area. During this phase, due to the increase of space in the cold focus and the overall increase of volume in the system, the gas loses pressure and gets colder.
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Phase 4-1:This phase ends in the initial state, the displacer piston finishes at the bottom and the power piston starts going down. As the air cools and loses pressure, the power piston can go down and start the cycle again, with the assistance of the flywheel that spins at a certain speed due to the previous cycle.
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