The revolutionary Libralato 6-phase Cycle

The Libralato R6 eco-engine dispenses with the need for conventional cylinders, pistons, con-rods, crankshafts, valvetrains and camshafts. The R6 eco-engine has only five moving parts: the two rotors, the shaft and the shaft mounted drive bars. All the bearings are set away from the hot zones of the engine and easy to lubricate, with an oil circuit running through the shaft. Two inter-locking rotors (a power rotor and a following rotor) on different rotational axes, exchange gases between four dynamic chambers (intake, compression, combustion and expansion) without a throttle body and with no pumping losses.

At top dead centre, the dual rotor architecture switches instantly from compression to expansion with no loss of momentum, which allows exceptionally high compression and combustion pressures whilst avoiding the damaging effects of engine knock. The expansion volume is 37% greater than the compression volume. The power rotor directly converts the pressure of this over expansion to torque at the output shaft with much greater mechanical leverage, over a much greater duration than a piston/connecting-rod/ crankshaft architecture. The mechanically simple architecture enables Homogenous Charge Compression Ignition (HCCI), Variable Compression Ratio (VCR) and internal Exhaust Gas Recirculation (EGR) in ways that are easy to control, with exceptioanlly high levels of torque, very low vibration and very low exhaust temperature and noise.

R6 Exploded View (back) sml

Libralato R6 eco-engine exploded view

R6 Libralato Cycle

The Libralato engine has a revolutionary new 6-phase cycle, with all 6 phases completed in each rotation of the engine. Compared to the R6 eco engine’s parallel 6 phase thermodynamic cycle, the sequential four stroke cycles of Otto and Diesel are archaic – from the Victorian era! With a combustion chamber at the top and open exhaust and intake ports near the bottom, the motion of the rotors forms three dynamic chambers in every revolution. Broadly speaking the six phases (1) intake, 2) first compression, 3) scavenge/ exhaust gas recirculation (EGR), 4) second compression, 5) expansion, 6) exhaust) act in three pairs each revolution: a) whilst intake fills the centre from the bottom, a second compression takes place on the right; b) whilst expansion takes place on the left, a first compression takes place in the centre and on the right; c) immediately after the exhaust at the bottom, a scavenge/EGR takes place at the top and into the centre. .

The following diagrams illustrate the key points in the Libralato R6 engine cycle.

Libralato Cycle 00 TDC image

Fig.1 - Libralato Cycle 00 TDC

Libralato Cycle 040 image

Fig.2 - Libralato Cycle 040

Libralato Cycle 165 image

Fig.3 - Libralato Cycle 165

Libralato Cycle 182 image

Fig.4 - Libralato Cycle 215

Libralato Cycle 225 image

Fig.5 - Libralato Cycle 225

Libralato Cycle 260 image

Fig.6 - Libralato Cycle 260

The graph below illustrates the Libralato cycle chamber volumes across 360o of rotation.

Libralato cycle volumes with valve timings

The graphs below show comparisons between the Libralato cycle and the Otto and Diesel cycles. The Libralato R6 eco engine is an historic breakthrough in engine design, capable of >50% brake efficiency; Euro 6/7 emissions compliance without aftertreatment; <2kW/kg; <125kW/L; <$15/kW cost. Libralato was a finalist in the Mondial.Tech Startup Awards for Sustainable Mobility 2018 and the Collaborate to Innovate awards in 2019.

Libralato cycle comparison with Otto and Diesel

    R6 Mechanical Advantage

    R6 eco-engine summary

    R6 HCCI