Based on the problems caused by today conventional vehicles, much attention has been put on the fuel cell vehicles researches. However, using a fuel cell system is not adequate alone in transportation applications, because the load power profile includes transient that is not compatible with the fuel cell dynamic. To resolve this problem, hybridization of the fuel cell and energy storage device...

An optimal control ready model of a diesel-electric powertrain is developed, validated and provided to the research community. The aim of the model is to facilitate studies of the transient control of diesel-electric powertrains and also to provide a model for developers of optimization tools. The resulting model is a four state three control mean value engine model that captures the significan...

Conclusion A simple guidance law for operation of dual-fuel SSTO launch vehicles has been developed and used to determine the optimal value of the transition Mach number from dual fuel to single fuel. For the example considered, the optimal transition Mach number was 9.0 along a fixed trajectory. Along an optimal trajectory, the best transition Mach number was 9.6; the optimal trajectory had hi...

which clearly reduces to the vacuum case deŽ ned by Eq. (3) as ̄ ! 0. The velocity- ight-path-angle proŽ le is shown in Fig. 2 for a range of drag parameters ̄ . It can be seen that as the effect of air drag increases, the trajectory curves more quickly toward the local vertical.Because the effect of drag is to increasethe effectivethrustweight ratio of the vehicle, the descentmaneuvermay be com...

We present a new approach to solve optimal control problems of the monotone follower type. The key feature of our approach is that it allows to include an arbitrary dynamic fuel constraint. Instead of dynamic programming, we use the convexity of our cost functional to derive a first order characterization of optimal policies based on the Snell envelope of the objective functional’s gradient at ...

Improvements in hybrid electric vehicle fuel economy with reduced emissions strongly depend on their supervisory control strategy. In order to develop an efficient real-time supervisory control strategy for a series hybrid electric bus, the proposed equivalent fuel consumption optimal control strategy is compared with two popular strategies, thermostat and power follower, using backward simulat...