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This paper follows on from a previous publication [1] and describes the continued development of a generic Integrated Powertrain (IPT) model. Simulation tools have been used for many years in engine and vehicle development programmes, to predict fuel consumption and emissions over various drive cycles. The concept phase of these programmes typically considers the overall layout and sizing of the components, with the detailed control strategies developed later. Today, the increased integration of vehicle sub-systems requires a high degree of overall control early in the programme, firstly, to allow the sub-systems to function, and secondly, to apply a similar quality of system control to each hardware iteration. To address this issue, a control hierarchy has been applied comprising of a supervisor controller and multiple local controllers.

In a collaborative programme, the effects of gasoline sulphur content on regulated emissions from three-way catalyst equipped vehicles have been studied. The programme evaluated the sulphur tolerance of three different catalyst formulations on the same range of vehicles. The catalyst chemistries were chosen to be representative of typical current formulations in different markets, as follows: 1. Platinum/Rhodium (Pt/Rh) 2. Platinum/Rhodium/Nickel (Pt/Rh/Ni) 3. Palladium/Rhodium (Pd/Rh) Each vehicle/catalyst combination was tested with fuels containing sulphur at nominal levels of 50, 250 and 450 ppm weight. All fuels were produced using the low sulphur fuel as a base and doping to 250 and 450 ppm S with a mixture of nine sulphur compounds, typical of those actually occurring in European gasolines. The results show clear differences between the magnitudes of the sulphur effect with different catalyst formulations.

The effects of fuel formulation changes on vehicles meeting European Stage 1 (91/441/EEC) and Stage II (94/12/EC) emission limits have been investigated. Vehicles in the Euro Stage II fleet were advanced specification versions of the vehicle models in the Euro Stage I fleet. However, the basic engine blocks and capacity were the same. The observed improvements in emissions were attributed to changes, such as position of the catalyst and lambda sensor, improved fuel delivery systems, and to improvements in engine control strategy. These engine modifications resulted in reduced catalyst light-off times and improved AFR control. Emissions improvements, over the modified European test cycle, as a result of these changes were approximately 50% for CO and NOx and 30% for THC. A fuel matrix was designed in order to study the effect of six fuel parameters on exhaust emissions from the two levels of vehicle technology.