Yusuke Hasegawa

Energy efficiency improvement of series hybrid vehicle

Abstract A series hybrid electric vehicle is potentially suitable for operating at the optimum range of electricity generation, as its generator and propulsion motor are mechanically separated. The present system was developed by taking advantage of its characteristics for drastic improvement of fuel economy. In this study the real-time generating and the tracing bottom line of the engines brake specific fuel consumption (BSFC) characteristics were mainly used to achieve improved energy transfer efficiency, minimized energy storage and improved generating efficiency. The system was tested on a vehicle of 1500xa0kg equivalent inertia weight and achieved a 94% or greater improvement of fuel economy.

Application of Fluid Dynamics Model to Estimate Cylinder Intake Volume

In a conventional fuel metering control system (speed density method) for an internal combustion engine, the fuel injection amount during transient operation is usually determined by using mapped data and various settings in a feedforward system predetermined through experimentation. However, this still does not necessarily represent the ideal level of compensation under a diverse range of environmental conditions. In order to satisfy various demanding requirements, such as reducing emissions, it is vital that the controllability of the air excess ratio ({lambda}) be enhanced. The main technological obstacle that needs to be overcome is how best to determine accurately the required fuel amount from the engine in the feedforward system. To enable accurate prediction of the cylinder intake air volume, physical formulas of fluid dynamics were used to facilitate formulation of a model for the dynamic behavior of the intake air. In order to allow real-time calculation, an extremely simple yet highly accurate injection fuel amount calculation was used, in which certain elements are combined with the conventional speed density method. This enabled the controllability {lambda} to be dramatically enhanced. In addition, the number of transient fuel compensation items were substantially reduced.