Compressed gas is relatively expensive source of energy. When compressed gas is used for propelling of pneumatically driven vehicle, efficient gas utilization is favoured. Design and control strategy of pneumatic cylinder, with the emphasis on effective energy conversion is being discussed in this paper. Mathematical model, results of computer simulation and experimental work are provided and discussed. Experimental research is performed on the competition vehicle, equipped with pneumatically driven piston motor and instrumented. Relative significance of various geometric and control parameters of pneumatic cylinder on efficiency of energy conversion is presented.