A new pneumatic motor is presented where the pneumatic to mechanical energy conversion is based on double effect linear actuators. The parallel running cylinders are pneumatically coupled through intake, transfer and exhaust valves which allow to combine constant pressure displacement work and thermodynamic expansion work in order to reach an augmented energy efficiency. The linear motion of the actuator assembly is transformed into a rotational movement through an original connecting-rod based mechanism pushing and pulling lever-arms which are coupled to freewheeling clutch bearings. The paper shows the different variable as forces, torque, power and produced mechanical work. The energetic performance of the new engine is analysed, and finally, a small dimension demonstrator is presented.