Epicyclic Crankshaft

Imagine an ordinary four cylinder in-line, four stroke engine with five main bearings. (This system wouldn’t be limited to such a configuration, but let’s take this as a simple initial case.)

Each throw of the crankshaft is replaced by a pair of identical epicyclic gearboxes, one each side of the conrod. The big end bearing is attached (eccentrically) to the planet cages on each side of the conrod. The crankshaft itself is replaced by five short shafts in each main bearing. Each end of each shaft (apart from the end bearings) is splined into the sun wheel of a gearbox.

The annuli are fixed (in relation to the cylinder block), so that power is transferred to the “crankshaft” as usual. The velocity of the crankshaft in relation to the four stroke cycle will, of course, be determined by the ratio of the gears in the gearbox

Now if you rotate the annuli of a pair of gearboxes through a small arc, you can change the TDC of that piston relative to the other pistons in the engine. Thus you could change a four cylinder engine to become, in effect, a single cylinder engine with all the power strokes occurring at the same time, or a twin, with even (BMW) or uneven (Harley et al) power strokes.

Valve timings could be varied by a similar linked system on the camshaft or possibly pneumatically or electro-magnetically. Injection and ignition timing would be fully electronic. Tuning the exhaust might pose some problems.

Now you have a car with the low down grunt for pulling away from the lights and high end smooth cruising.