Development Experience of a Poppet-Valved Two-Stroke Flagship Engine

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.