A Polish company in co-operation with research institutes has developed a prototype of two-piston combustion engine working with two pistons moving in one combustion chamber in a collinear manner. One of the pistons works in a two-stroke and the other in a four-stroke cycle. The engine is devoid of a typical timing gear system and enables changing of the compression ratio. The company is looking for a technical cooperation and/or license agreement.

The principle of operation of the new engine is based on connecting and making use of advantages of both two- and four-stroke engines. The engine is built of two modules: two-stroke and four-stroke module. Cylinders of these two parts have been combined along one axis with a common head ? ring, and the pistons move at different velocities with appropriate phase shift in the same axial direction. The engine is equipped with two crankshafts, whose turning velocities are synchronised in such
a manner that the four-stroke part crankshaft turns two times faster than the two-stroke part crankshaft.
Construction of this engine made it possible to practically eliminate the effect which has always existed in classic two-stroke engines: sudden drop of pressure in the cylinder caused by early exposure of the exhaust port by the piston caused excessive loss of energy of not fully decompressed exhaust gases. Construction of the new engine makes it possible to make effective use of curve of adiabatic decompression of exhaust gases between the two pistons ? when the piston exposes the exhaust port the overpressure of the exhaust gases is already low. At the same time the moment of load exchange is delayed considerably in comparison to the classic two-stroke engines (early exposure of exhaust port is connected with the efficiency of load exchange process) and is fully realised on the compression curve, with slight overpressure of the loaded medium. This overpressure, applied by a compressor (blower), has favourable influence on completeness of cylinder flushing.
A favourable course of volume change in the cylinder working space exists in this engine. This enables obtaining such combustion conditions, which make it possible for the engine to work with low compression ratios during compression of the medium in the cylinder, simultaneously ensuring high expansion ratio. This feature enables usage of fuels with low octane number and continuous change of crankshafts polar shift can cause adjustment (automatic selection) of the compression ratio, proper for the engine partial loads and better fuels.
In order to improve the working conditions and ecological parameters it is possible to use advanced integrated injection-ignition system controlled electronically.

Innovative Aspects:
- Co-operation of two pistons moving in a collinear manner in one combustion chamber.
- Improvement of charge exchange and the combustion process due to the difference in piston velocities and the dynamic interaction of the four-stroke part piston.
- Elimination of the classic timing gear system.
- Possibility of using multiple fuels.
- Possibility of changing the compression ratio during operation, appropriately to the temporal engine load.

Main Advantages:
- Usage of low-octane number fuels.
- Limiting of toxic substances and heat emission.
- Low weight, simpler construction, decreased failure frequency.
- Higher values of working parameters (efficiency, torque, and power per unit volume).
- Increase in cylinder filling factor.
- Good cylinder flushing making it possible to obtain the exhaust gas composition comparable to classic four-stroke engine.
- Possibility of influencing charge exchange by controlling of the beginning of fresh charge admission.
- Favourable course of working space volume change during compression of the medium with variable polar shift of the crankshafts, which enables controlling the pressure in the cylinder (within certain limit).
- Almost invariable volume increase during expansion of the medium at various piston positions, which influences smoothness of power transfer.
- Piston-swept capacity is constant irrespective of changes of polar shift of the crankshafts.
- Efficiency characteristics can be very favourable for partial loads.
- Improvement of the charge exchange and combustion process due to the difference in piston velocity and dynamic interaction of the four-stroke part piston.
- Higher torque ? average theoretical pressure and considerably higher power in comparison to comparable engine with the same engine capacity.

• Design and Modelling / Prototypes
• Mechanical Engineering, Hydraulics, Vibration and Acoustic Engineering related to construction technology
• Design of Vehicles
• Road Vehicles

• Industrial manufacture
• Transport
• ENERGY

• Industrial Equipment and Machinery

• Technical Co-operation
• License agreement
• Financial resources