It is expected that heavy duty engine legislation in Europe will continue to drive down test cycle BSNox emissions to levels of between 2.5 and 3.5 g/kWh by 2005, with a reduction in particulate emissions to between 0.02 and 0.08 g/kWh. It is unlikely that re-optimisation of existing engine combustion systems alone, such as further retardation of the fuel injection timing, will be sufficient to meet the legislated BSNox targets. Other measures, such as cooled EGR or new aftertreatment systems must therefore be considered. Such emissions control strategies may conflict with other market requirements for improved fuel consumption and increased power density.In this paper, research at Ricardo into the configuration of a premium heavy duty truck engine for the European market for model year 2005 and beyond, is described. A review of the market requirements, projected to 2005 was undertaken in order to define the specification of the concept engine.Cooled EGR was selected as the primary emissions control strategy. The impact of this strategy on engine rating and fuel consumption was comprehensively reviewed including a study of a wide range of different turbocharger and EGR circuit configurations. A wastegated, single stage turbocharged, turbocompounded engine was selected as the optimal solution. Further calculations were performed to study the potential of future developments in aftertreatment technology. Finally, a concept design of the engine was produced.