6-Phase Engine
The Italian constant-volume combustion engine with rotating connecting rod and semi-floating piston: more power, lower consumption, lower emissions.
The thermodynamic cycle reinvented
A predetermined-profile eccentric replaces the classic connecting rod–crank system, eliminating dead centres and allowing perfect isochoric combustion at TDC.
Designed to maximise power and reduce passive losses
Volumetric efficiency up to 120% of displacement, zero ignition advance and modular architecture derived from the automotive construction philosophy.
From automotive powertrain to industrial Stirling cycle
The 6-phase crankshaft principle applies to internal combustion, hybrid and Stirling cycle engines, opening scenarios of near-zero pollution and further reduced consumption.
The constant-volume combustion that redefines the modern engine
The Motor Union Italia 6-Phase Engine is an internal combustion engine that realises a thermodynamic cycle in six phases over two revolutions of the crankshaft. The heart of the invention is the new crankshaft system: a predetermined-profile eccentric, integral with the crankshaft, on which a roller keyed to the piston pin slides. This eliminates the classic dead centres and allows the kinematic law of the piston to be precisely defined.
The result is an Isochoric (Constant Volume) Combustion at Top Dead Centre with zero ignition advance, a prolonged intake at BDC with volumetric efficiencies greater than unity, and the elimination of losses due to combustion pressure during the advance period. All in a more compact, lighter engine built with an automotive philosophy.
Thermal Efficiency
Isochoric combustion at TDC
Zero ignition advance: all the energy of the mixture is converted into useful work without drawing energy from the flywheel during compression.
Volumetric Efficiency
Up to 120% of displacement
The prolonged intake with the piston stationary at BDC exploits the inertial velocity of the incoming mixture, achieving volumetric efficiencies greater than unity at medium and high speeds.
Compactness
Reduced powertrain volume and weight
Integrated with the belt-free, pulley-free stepless automatic transmission, the powertrain significantly reduces bulk, weight and costs compared to current solutions.
How the 6-Phase Engine works: the new eccentric crankshaft system
The system is based on a predetermined-profile eccentric integral with the crankshaft. A roller, keyed to the piston pin, slides on the eccentric profile: the piston therefore follows the kinematic law impressed in the profile, not the sinusoidal one of the classic connecting rod–crank mechanism. The designer can thus define dwells at TDC for isochoric combustion and dwells at BDC to maximise filling.
First Principle — Isochoric Combustion
Zero ignition advance, maximum energy
In the traditional system, ignition advance is necessary to complete combustion before the piston moves away from TDC, but it draws energy from the flywheel during compression. With the predetermined-profile eccentric, the piston stops at TDC for the chosen angle: combustion occurs at constant volume, with zero advance, transferring all thermal energy into pressure available for the expansion phase.
Second Principle — Prolonged Intake
Filling greater than unity at medium and high speeds
At Bottom Dead Centre the piston stops for a programmed angular interval, exploiting the inertial velocity of the incoming mixture column. The volumetric efficiency exceeds unity at medium and high speeds — up to 120% of geometric displacement — without resorting to forced supercharging, increasing mean effective pressure (MEP) naturally and reliably.
Technical and economic advantages over the state of the art
The comparison between the Motor Union Italia 6-Phase Engine and conventional 4-stroke engines highlights structural advantages in efficiency, emissions, compactness and costs. A technology designed for the era of the energy transition.
Thermodynamic efficiency
Isochoric combustion: no advance losses
Eliminating ignition advance removes energy losses during compression. All the pressure generated by combustion is available in the expansion phase, increasing specific power for the same displacement.
Natural filling
Volumetric efficiency up to 120%
The dwell at BDC exploits the inertia of the inducted mixture: at medium and high speeds, filling exceeds 100% of geometric displacement, increasing MEP without mechanical supercharging.
Construction simplicity
Fewer components, automotive philosophy
The eccentric system replaces the complex connecting rod–crank mechanism with a precision-machined profile. The automotive construction philosophy guarantees standardisation, reduced production costs and global availability of components.
Fixed-pitch blades — rotor
Rotating connecting rod and semi-floating piston
The rotating connecting rod and semi-floating piston configuration promotes thermal stability at high temperatures, optimal lubrication and a piston mass equal to or less than that of an equivalent conventional displacement, reducing inertial forces.
Emissions and acoustics
Towards near-zero pollution
Integrated with the Stirling cycle, the engine targets emissions compliant with California standards (among the most stringent in the world), with acoustic pollution below 70 dB and use of very low octane fuels, free of anti-knock additives.
Compact powertrain
Reduced volume and weight with stepless transmission
Combined with the belt-free, pulley-free stepless automatic transmission, the powertrain significantly reduces bulk and weight compared to current solutions, with direct benefits for consumption, vehicle dynamics and integration costs.
Conventional 4-stroke engines require ignition advance, operate with volumetric efficiencies below unity and accumulate passive losses in the compression phase. The Motor Union Italia 6-Phase Engine eliminates these structural losses through isochoric combustion, prolonged intake and the new crankshaft system — a technically distinct category that positions itself as the natural evolution of the internal combustion engine for the energy transition.