Henry Bensler

A PDF-Based Model for Full Cycle Simulation of Direct Injected Engines

In one-dimensional engine simulation programs the simulation of engine performance is mostly done by parameter fitting in order to match simulations with experimental data. The extensive fitting procedure is especially needed for emissions formation - CO, HC, NO, soot - simulations. An alternative to this approach is, to calculate the emissions based on detailed kinetic models. This however demands that the in-cylinder combustion-flow interaction can be modeled accurately, and that the CPU time needed for the model is still acceptable. PDF based stochastic reactor models offer one possible solution. They usually introduce only one (time dependent) parameter - the mixing time - to model the influence of flow on the chemistry. They offer the prediction of the heat release, together with all emission formation, if the optimum mixing time is given. Hence parameter fitting for a number of kinetic processes, that depend also on the in cylinder flow conditions is replaced by a single parameter fitting for the turbulent mixing time. In this work a PDF based model was implemented and coupled to the full cycle engine simulation tool, WAVE, and calculations were compared to engine experiments. Modeling results show good agreement with the experiments and show that PDF based Dl models can be used for fast and accurate simulation of Dl engine emissions and performance.

A User-Centric Approach for Efficient Daily Mobility Planning in E-Vehicle Infrastructure Networks

The next generation of e-vehicles will be assessed on their ability to master the challenges posed by urbanization, resource restrictions and increasingly flexible and diverse user demands. Presumably, the vehicle-user-infrastructure network will become too dynamic and complex for an individual user to fathom without some sort of automated assistance. This paper proposes a user-centric, constraint-based, in-vehicle travel planning system, which schedules a daily travel plan of a user by exploiting knowledge about current and future states of the vehicle-user-infrastructure network. The system is implemented in an agent-based framework and is evaluated by a traffic simulator that additionally incorporates parking and charging lots together with an availability monitoring and booking service. The benefit of the planning system is assessed in a traffic simulation, where vehicles with and without a planning system compete for available resources. It can be shown that proactive conflict management and resource scheduling can reduce parking search time and overall travel time. Furthermore it can be shown that the adherence to schedule can be significantly improved.