In this study we present a procedure for the design and implementation of a control strategy to optimize energy use within a light weight hydraulic hybrid passenger vehicle. The hydraulic hybrid utilizes a high pressure accumulator for energy storage which has superior power density than conventional battery technology. This makes fluid power attractive for urban driving applications in which there are frequent starts and stops and large startup power demands. The proposed design method improves the powertrain's operational efficiency by finding the best balance between optimizing individual component efficiencies. The optimization problem was implemented using the model predictive control framework because it requires no future information about the drive cycle in its design. Hardware-in-the-loop experiments using an electro-hydraulic powertrain testbed were then used to validate the dynamic model and control performance.