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Preliminary bench tests have been carried out on an original-design 2-stroke single-cylinder prototype engine, which is equipped with an electronically controlled gasoline direct injection apparatus. The main design and operating features of the engine concern: a unidirectional airflow during the scavenging process (from the inlet ports near the BDC to overhead cam-actuated valves), an external air pump (a Roots volumetric type driven by an electric motor) and a force-feed lubrication system, like those usually exploited in mass-produced 4-stroke engines. Experimental bench tests were carried out under low load, intermediate rotational speed operating conditions. The performances were compared to those obtained from a commercial crankcase-scavenged 2-stroke engine using an indirect injection fuel feeding system. Encouraging results were obtained as far as fuel consumption and pollutant emissions are concerned.

The aim of this study was to find a convenient set-up for an innovative engine dedicated to light aircraft through a numerical one-dimensional simulation. Six different engine layouts were analyzed in order to find the highest power/weight ratio and the least voluminous configuration. The first was a four cylinder, four stroke, horizontally opposed, naturally aspirated, water cooled engine with 16 valves that delivered 75 kW (∼100 bhp) at 2400 rpm for an estimated weight of 65 kg. A gearbox was also used in the naturally aspirated model to decrease the displacement, the weight and the overall dimensions. The other solutions involved these two engines in a turbocharged layout in order to gain a further downsizing. The supercharging was obtained through a centrifugal compressor driven by an exhaust-gas driven turbine, which also allows the power to be restored at cruising altitude.