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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.

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.