A High Efficiency Pneumatic Motor Based on Double-Acting Linear Cylinders
- Country : Switzerland
- Subject : Ecole Polytechnique
A high efficiency pneumatic motor is presented, based on the coupling of two double-acting linear cylinders. The pneumatic motor is used in a chain of compressed air energy storage and drives an electric generator. The principle of coupling two cylinders of different sections allows to produce, in addition to the normal displacement work of the cylinders an additional amount of expansion work. This additional work finally elevates the total conversion efficiency of the motor, in comparison with the efficiency of a motor using a simple cylinder without expansion work and consuming an identical quantity of compressed air from the feeding reservoir. The use of cylinders with a section ratio of four leads to a doubling of the energy efficiency. The paper includes the simulation of a single cylinder system as well as the new proposed motor. Pressures in the chambers are presented as well as the developed torques at the output of the crankshaft. The paper includes the calculation of the efficiencies, based on the injected enthalpy. Then, the paper presents an original evolution of the motor in which the same performance can be achieved with one cylinder only. Finally, the paper presents an experimental set-up realized at a low power level.