A pneumatic motor is studied where the pneumatic actuators consist of
linear cylinders. This mechanical principle based on the use of a crankshaft and piston
rods has the inherent property of being reversible. For this system, the same principle
of adding expansion work with an additional volume is applied as it was in the previous
chapter for semi-rotary actuators.
The mechanical behavior of the crankshaft and piston rod is described, and the
following pneumatic displacement and expansion work is simulated. Two different
architectures are simulated, namely, first, a system with pistons operating in phase and
second, with alternating pistons. The energy efficiency of the new motor is calculated
and compared with the efficiency of a system using a single linear cylinder.
Further, the principle of realizing the expansion work in the same cylinder as for the
displacement work is applied to the motor with linear cylinders. The torque, power and
converted work are presented with the simulation results. The study is completed with
the presentation of a physical demonstrator system.
Keywords: Adiabatic expansion, Alternating piston-rods, Energy efficiency, Expansion work, In-phase piston rods, Linear cylinders, Pneumatic motor, Torques.
