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A new method of solution is presented for the equations governing unsteady flow field during compression and combustion in a spark ignition. The Lagrangian approach, an application of a vortex method to the three-dimensional solution of the continuity and conservation equations, avoids the need for a turbulence model and wall laws close to the surfaces. Vorticity is introduced as blobs close to the wall which diffuse into the main flow. The potential equation is solved by the boundary element method. Combustion is treated as a thin sheet propagating at laminar flame speed using an extension of the simple line interface method to three-dimensions, now called a simple plane interface method. The code is demonstrated in application to a wedge shaped combustion chamber with surface irregularities closely approximating the actual shape.

The gaseous fuels, hydrogen and methane, are fuels that will likely be in adequate supply when crude oil sourced liquid fuels are scarce. These gases may he used directly in engines, which may need modification or could be used as feed stocks for liquid fuel synthesis. The energy efficiency of using methane and hydrogen in dedicated engines is compared with liquid fuelled engines. Hydrogen gives 6 3% improved efficiency and Methane 39% in city driving and Methane gives slightly improved power but Hydrogen fuel causes a 25% power loss compared with petrol. The storage of Methane in compressed or liquid form and Hydrogen in metal hydrides are compared. The overall efficiency of these gaseous fuel systems are compared, and fuel synthesis is included.

A high speed research engine has optical access to over 80% of the combustion chamber volume through a piston with a quartz window. The engine has been used to study the effect of swirl on the spark-ignited combustion by means of high speed photography and analysis of combustion-time data. Results over the speed, swirl and mixture strength range show the flame travel derived from the pressure to agree with the measured flame travel to within 3% on average. Turbulent to laminar flame speed ratios as high as 45 occur under high swirl conditions. However it was not possible to find a predictive model which could explain the turbulent flame speed in terms of engine design variables.

A fleet of 17 utility, van and flat tray bodied trucks has been tested for fuel consumption and exhaust emissions over a range of drive cycles and steady state operating conditions. The influence of vehicle load on the results was included. For each vehicle the tractive force applied by the chassis dynamometer, on which testing was performed, was adjusted to match those found on the road using a new procedure. The fuel consumption results show a downward trend with model year (1.7% annum); about 30% higher petrol use compared with diesel; a cold start penalty of 3 L/100 km and over 2:1 variation for vehicles capable of identical transport task. Exhaust emissions from these rigid trucks were between 3 and 6 times greater than those of the passenger car fleet.

A thermodynamic model has been employed to study the effect of changing injection timing, spray angle, fuel density, fuel viscosity, chemical reaction rate constants and air entrainment on the combustion performance of seed oils and their methyl esters in an open chamber diesel engine. It is shown that the most important valuables affecting the performance are fuel density and fuel viscosity. It is deduced that modification of these physical properties can lead to substantial improvement in the combustion performance of the seed oils.

An upgraded vehicle fuel consumption/emission test facility is shown to be able to simulate on-road performance of cars up to wide open throttle operation. A procedure is described which permits dynamometer loads to be set so as to replicate the on-road, steady speed fuel consumption of each vehicle tested. A test program involving five driving cycles (schedules), three US and two Australian, and a range of other manoeuvres has been devised, to describe a wide range of on-road driving. The tests last one week and have been carried out on a fleet of almost 40 cars. Fuel and emission data has been logged at every half second interval of the tests. The overall test results only have been reported here. It is shown that there is considerable variability in the response of individual cars to changed test cycle. For the Australian test cycle fuel consumption is typically 15% higher than to US 75 FTP city test schedule.

The models presented for predicting fuel consumption and emissions for vehicles driven on the road provide the means for averaging and storing results obtained from vehicle tests usually carried out at an emissions test facility to standard and non-standard-drive schedules. For hot start fuel usage and emissions rates the models, in descending order of temporal or spatial resolving capability, include: transient engine mapping (a new model), steady state engine mapping, vehicle mapping, power demand, modal or elemental, lumped parameter (PKE-v) and travel time variants. The engine mapping model is shown to be able to predict instantaneous on-road fuel consumption with good precision (±3ml) for one vehicle over a selected 3.3 km stretch of road. Its emissions rate predicting ability is less satisfactory. When link-by-link fuel is needed the 6 coefficient PKE-v model performs well (R = 0.994).