Search Results

The transient behaviour of the fuel spray from an air assisted fuel injector has been investigated both numerically and experimentally in a Constant Volume Chamber (CVC) and an optical engine. This two phase injector is difficult to analyse numerically and experimentally because of the strong coupling between the gas and liquid phases. The gas driven atomization of liquid fuel involves liquid film formation, separation and break up and also liquid droplet coalescence, break up, splashing, bouncing, evaporation and collision. Furthermore, the liquid phase is the dominant phase in many regions within the injector. Experimental results are obtained by using Mie scattering, Laser Induced Fluorescence (LIF) and Laser Sheet Drop sizing (LSD) techniques. Computational results are obtained by using a mixed Lagrangian/Eulerian approach in a commercial Computational Fluid Dynamic (CFD) code.

A survey of the on-road petrol consumption of Australian passenger cars provided data which has been analysed for effects on fuel consumption caused by features such as transmission type, vehicle inertia class, engine size, air conditioning presence and vehicle location. Results show that cars with automatic transmissions consistently have higher petrol consumption than manuals for all inertia classes - 15% higher in city conditions and 11% higher in highway conditions. There is also a penalty for automatic transmissions at most engine sizes, although the penalty is relatively larger for smaller engine capacities. Presence of air conditioning was found to increase petrol consumption by 13.5% on average, but the data did not allow the impact of frequency of use to be determined. Coastal driving conditions resulted in petrol consumption being 9.4% higher than for inland conditions, and cars driven in winter had 4.4% greater fuel consumption than cars driven in summer.