PATTAKON

Greece

GrecoHelp

Gentle Rolling Efficient Crankless Operation

A "first order" cam activates "desmodromically" a reciprocating piston, without crankshaft, without connecting rods.

The "Greco3" (three cylinder in line, even firing) is perfectly balanced, as perfectly as the Wankel rotary engine.

The "Greco3" is much better balanced than any six (straight or boxer or Vee or …).

It is also better balanced than any eight cylinder engine.

Compact and light compared to competitors. For instance, the GrecoU6 (six cylinder in U, even firing) is not longer than the conventional three in line, it is as balanced as the conventional V-12, it is only a little wider than the conventional three in line and it uses a unique (single piece) cylinder head.

What makes the difference is the geometry of the cam profile.

Unlike a multi-lobe cam, the rotation of the single-lobe cam is of the same order (frequency) as the reciprocation of the piston, thereby the webs on the counter-rotating shafts can (depending on cam profile) fully balance the forces and the moments.

As the total kinetic energy of the three harmonically reciprocating pistons of the "Greco3" remains absolutely constant, all along a revolution, there is no inertia torque altogether, making the engine as perfectly balanced as the rotary engine of Felix Wankel (somewhat better than best V-12).

The "Greco4" (straight four, even firing) uses a unique, "single piece" shaft with a single-lobe cam for each cylinder.

The "Greco4" is perfectly balanced as regards forces and moments. It is as balanced as the high quality conventional straight four (SAAB, BMW, Mercedes, Opel etc) which use a pair of additional double speed, counter-rotating balancing shafts, i.e. a total of three shafts and the associated "gearings". The "Greco4" comprises only one shaft rotating at normal speed, i.e. one shaft altogether and no gearings at all.

The "rods" connecting the upper part to the lower part of the piston assembly, could be just wires, as they are loaded with only tension loads.

Cam Lobe geometry

The "basic curve", top left, has an eccentricity described as:

E(f)=a + r*sin(f).