Abstract
The goal is to establish a bench mark for best practice fuel consumption for a theoretical hybrid vehicle with lean burn, high efficiency gasoline engine with all electric pumps and ancillaries, optimised motor size of high efficiency design and multispeed transmission matched to an E class vehicle. In the process to identify the contribution of each refinement using a well established optimizer and modelling. This paper examines the benefits of the introduction of increasing levels of engine efficiency through ultra lean burn and turbocharging and including all electric ancillaries and water and oil pumps in a full parallel hybrid, using an well proven optimizer to obtain best sizing of components with ability to maintain SOC under a wide range of driving through a real time energy management (EMS) optimizing algorithm and with a vehicle 0-100km/h acceleration of 7 seconds. Although much of this work is based on experimental validation, the future steps are theoretical explorations to provide estimates of likely best practice and to project what targets might be possible for this class of vehicle in the longer term. For the hybrid case the fuel consumption in the NEDC an E segment car over the NEDC might achieve 3.77 L/100km or about 87 gCO2/km by 2020, and probably by 2030 or later, an ultimate ICE, fuel consumption of 3.05 L/100km or 70 gCO2/km over the NEDC is predicted or when fully optimized about 12% better than 2020; that is a fuel and CO2 emission consumption reduction of overt 2/3 from present values, without any attention to mass reduction, aerodynamic drag and rolling resistance improvement. When best motor efficiencies and control plus electric parasitic drives, and the use of ‘look-ahead’ systems further reduce fuel consumption to close to 2L/100 km; a reduction of around 76% or an increase in fuel economy of nearly 4.5 times. This work sets out the likely long term bench mark for best possible practice of CO2 that includes look-ahead driving possible though vehicle-to-vehicle communication for the example here of a large high-performance car. What can still be done is the implementation of reduction in vehicle mass, aerodynamics and rolling resistance that will result in further benefits.
KEYWORDS – hybrid electric vehicle, efficiency, electric parasitics, bench mark practice, fuel consumption