Politecnico di Torino - Corso Duca degli Abruzzi, 24 - 10129 Torino, ITALY

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compression ignitionDirect InjectionMulti Fuel Combustionopposed pistonTwo Stroke Engine


The invention consists in the combustion system optimization of a 2-Stroke Compression Ignition opposed-piston engine. It enables a reduced number of standard components, while achieving a complete and clean combustion, along with very low heat losses. Many types of fuels can be employed, gasoline included.

Technical features

The proposed system enables an ideal mixing between air and fuel vapor, promoting a smooth and complete diffusive combustion. As a result, relatively low air-fuel ratio can be adopted, achieving high power density along with reduced pollutant emissions. No specific injection technology is required: on the contrary, the number of components is reduced, in comparison to equivalent 2-S engines (one injector per cylinder, instead of two). Another peculiarity of this combustion concept is the presence, along the cylinder liner, of a thin layer of air, working as an insulant, reducing heat transfer through the walls. Thermal losses are already very low, in comparison to typical 4-Strokes, due to the minimization of the surface of the combustion chamber (more regular shape of the pistons crown, no cylinder head).

Possible Applications

  • Ground and Marine propulsion, forunit  displacement up to 0.75L per piston;
  • Industrial applications (high efficiency, low costs and emissions);
  • UAVs and light aircraft (high power/weight ratio);
  • Range-extender and APU (compactness, efficiency, cost).


  • Smooth and complete combustion, for different liquid fuels;
  • Low heat losses;
  • High specific power;
  •  Low polluting emissions;
  •  Reduction of fuel consumption and CO2, in comparison to 4-strokes;
  •  Standard fuel injection components