Acceleration Test Method for a High Performance Two-Stroke Racing Engine

This paper describes an inertial dynamometer system which has been applied to the testing of small two-stroke kart racing engines. The dynamometer incorporates a flywheel of appropriate moment of inertia to simulate the mass of a kart and driver. The test procedure involves measurement of the flywheel speed during an acceleration phase resulting from opening the throttle. Calculation of the instantaneous flywheel acceleration corresponding to each engine speed directly gives a measure of the torque and power characteristics. Performance results, including exhaust pressure traces, are presented from a series of tests conducted on a 100 cm³ kart engine. The results are compared with corresponding steady state measurements recorded on an eddy current dynamometer. In addition, the measured results are compared with predictions from a computer simulation.