Fuel Consumption Minimization, with Emissions Constraints, for Diesel Powered Cars

State-of-the-art engine models are used to study the emissions production, and fuel consumption minimization, of a typical diesel-powered road car operating on a variable-gradient road. The engine models, which have been fit to measured test cell data, are used to represent both the performance and emissions generation characteristics of a typical diesel-fuelled car engine. A simple example is used to highlight the impact of elevation changes on the main structural features of fuel optimal control problems (OCPs). A typical semiurban test route with legislated speed limits and enforced stops is used for performance evaluation purposes. The optimal functioning of a discrete-gear automatic transmission system, as opposed to a simple continuously variable transmission, is studied in detail. The main focus of this paper is to evaluate the importance of 3-D road influences (gradient and curvature), preimposed time-of-arrival constraints, enforced stops, and emissions constraints on the fuel consumption and optimal driving of typical diesel-powered road vehicles. This paper proposes the use of multiple-phase optimal control to elicit a better understanding of 'real' driving situations and motivates a move away from standardized drive cycles.