Impact of alternative controller strategies on exhaust emissions from an integrated diesel/continuously variable transmission powertrain

Abstract The use of an integrated powertrain including a continuously variable transmission (CVT) offers great scope for improvements in fuel consumption and emissions, although this must be achieved without adversely affecting vehicle drivability. These conflicting aims can best be resolved by the use of novel control strategies designed from the outset with these considerations in mind. Two alternative approaches to the task are presented here. These made use of artificial intelligence and more traditional and intuitive methods to allow the maximum flexibility in operation. Both strategies incorporated a novel optimization routine described in a companion paper to locate the best operating point for the engine. The two strategies were implemented for an integrated diesel CVT powertrain and compared with an existing controller and the equivalent manual transmission powertrain. Chassis dynamometer results show the newly designed controller strategies to have significant impact on vehicle exhaust emissions, while the structure of the software allows the controller action to be highly tuneable and fexible in order to balance the vehicle drivability requirements with economy and emissions targets.