Analytical design of a parallel hybrid electric powertrain for sports utility vehicles and heavy trucks
In conventional vehicles, the entire power is derived from the IC engine, so, it is obligatory to size the engine larger than necessary for its cruising speed. The engine is to be designed to account for peak power requirements like acceleration. This over sizing the engine shifts the operating point from its efficient zone and this adversely affects the fuel economy and emissions. The idea of hybridization is that a part of the total power required can be replaced by an auxiliary power source, generally a motor powered by batteries. Hence, the IC engine can be designed for average load and can be operated with better fuel rfficiency. A simulation tool called ADVISOR (Advanced Vehicular Simulator) is used for this study. The software takes the vehicle input and the drive cycle from the user, simulates the vehicle drive and gives fuel economy, acceleration performance and emissions. In this study, each of the three vehicle platforms (light SUV, full size SUV and Heavy Truck) is selected and a reasonable power level for that vehicle platform is taken from the data of the current conventional vehicle type. The powertrain is then hybridized by replacing (in steps) this power by an equivalent motor power and a simulation is run, such simulations are run in Advisor at three different battery charge capacities to understand the effect of on board charge. The fuel economy and the time to accelerate from rest to 60 mph are noted down from the ADVISOR results. The cost optimization is also done by considering the cost of the motor along with the cost and space of the batteries. It also includes the replacement cost of the batteries. The benefits due to the decrease of operating costs will be shown in the fuel economy and the penalty due to the weight of the batteries is shown both in performance and fuel economy of the vehicle. Results showed that hybridization can improve the overall performance of the vehicle, but with the current cost of the batteries it may be a little costly. Since there is a lot of research into the development of compact and low cost batteries so that they could be carried along the vehicle, developments are anticipated in battery technology and design of fuel cells which could make the design of hybrid electric vehicles feasible and economical in the near future.
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:ic engine sport unitily vehicle peak power acceleration fuel economy emissions hybridization auxiliary source powertrain motor simulation cost optimization
Date of Publication:01/01/2003