<div class="section abstract"><div class="htmlview paragraph">A new compression engine brake has been developed for the Cummins L10 engine. High retarding power was required in order to compensate for the loss of natural retarding ability of modern heavy duty trucks resulting from fuel-saving devices. A computer model was used to select the most feasible design. The new concept utilizes one exhaust valve per cylinder with a valve reset mechanism. Prototype hardware was laboratory and field tested. Correlation between the test results and computer simulation is exhibited. A relationship between the Model 404 performance and the vehicle retarding capability is shown. This new engine brake model is one of the most efficient in terms of B.M.E.P. that Jacobs has developed.</div></div>