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A project has been carried out to develop a practical G-DI vehicle with very low emissions; primarily assessed over the European EUDC cycle, but with emissions consistent with ULEV, Euro Stage IV and Japan 2000 legislation whilst maintaining acceptable driveability. A combined test bed and vehicle programme was conducted. Vehicle benchmarking established target emissions reduction areas and testbed work characterised the combustion system. The programme was based on a Mitsubishi Carisma GDI™ vehicle. The vehicle used a prototype Lean NOx Trap (LNT) based aftertreatment system. The Ricardo Vehicle Engine Management Prototyping System (VEMPS) Control System replaced the OEM ECU giving control of drive components and strategies to regenerate LNT of stored NOx were developed. Constant torque during regeneration spikes was achieved. The fuel economy penalty of different regeneration strategies was investigated.

The gasoline-fuelled direct injection poppet-valved two-stroke engine described in (1) has been built in single cylinder form and tested to evaluate the potential of this concept as a passenger car powerplant. Development of the combustion and scavenge system is described. Following development, the engine produced a specific power output of 90 kW/litre at 5000 rev/min, with a peak torque of 200 Nm/litre at 2000-2500 rev/min. HC emissions were maintained in the range 3-15 g/kWh over the majority of the engine operating range and NOx emissions in the load range used in the FTP drive cycle were less than 3 g/kWh. Part load fuel consumption under steady state conditions was 8% lower than for a stoichiometric four-stroke engine sized for equal power output.