This proposal seeks to apply the successful results of basic research carried out under the Foresight Vehicle Programme 2/4SIGHT project. Using industry standard simulation tools, this study identified a petrol (gasoline) engine concept capable of delivering levels of CO2 and fuel consumption more typical of those of a modern diesel engine. In addition to CO2 benefits, the engine offers class leading levels of performance, and at a reduced cost relative to the diesel engine. This project will deliver a testbed demonstration of a highly downsized multi-cylinder engine, switching between 2-stroke and 4-stroke combustion modes in order to deliver class leading low speed torque and driveability characteristics more typical of an engine of twice that displacement. By doing so, the vehicle will deliver a 30% reduction in CO2 and fuel consumption (compared with the 3.0-4.0 litre engine) whilst complying with planned future European emissions legislation. This engine would be targetted in six-cylinder, 2.0 litre form at premium vehicles and SUVs with a three-cylinder 1.0 litre variant possible for family cars.