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Stringent global emissions legislations demand effective NOx reduction strategies for both the engine as well as the aftertreatment. Diesel applications have previously applied Lean NOx Catalysts (LNCs) [1, 2], but their reduction efficiency and longevity have been far less than that of the competing ammonia-based SCR systems, such as urea [3]. A catalyst has been developed to significantly reduce NOx emissions, approaching 60% with ULSD and exceeding 95% with E85. Both thermal and sulfur aging are applied, as well as on-engine aging, illustrating resilient performance to accommodate necessary life requirements. A robust system is developed to introduce both ULSD from the vehicle's tank as well as E85 (up to 85% ethanol with the balance being gasoline) from a moderately sized supplemental tank, enabling extended mileage service intervals to replenish the reductant, as compared with urea, particularly when coupled with an engine-out based NOx reduction technology, such as EGR.

A set of model fuels has been designed, using the Major-Component Fuel approach, to represent a range of gasoline mid-range and back-end volatilities. The thermo-physical properties of the model fuels have been used, together with a simple model of inlet system, to calculate liquid-vapour mass fractions in the inlet system, and the composition of the inlet port wall film. This has enabled the effects of gasoline volatility, speed, load and inlet port wall temperature to be studied systematically. The results indicate that, in cold start, only some 20-30% of the injected fuel is vapourised in the inlet port, leading to an accumulation of liquid fuel in the inlet port wall film reservoir. As the engine warms up, the mass of fuel in the reservoir decreases, and its composition changes, becoming progressively richer in heavy end species. Mid-range volatility affects the cold start behaviour, whilst back-end volatility affects the approach to fully-warmed up operation.