Hydrodynamic dynamometers can be used for the entire range of combustion engines from cart engines up to large ship engines, are inexpensive and have a small moment of inertia. Due to their strong nonlinearities and the absence of precise models, they are still rarely used for dynamic testing. Against this background, this paper proposes an inverse control of an approximate form determined experimentally. As the paper shows using measurements on a dynamic truck engine test bench, the proposed approach is able to offer a significantly better performance with respect to the classical implementation thus opening a new path for the intended use for dynamic testing. © 2011 AACC American Automatic Control Council.