Home of the Ultimate Driving Machine and bringer of Joy to drivers, BMW has revealed its latest powerplant and to the casual observer or diehard enthusiast neither corporate phrase sits very easily with the new engine.

The reason? It's a 3-cylinder, and it's low capacity. Buyers in Europe are used to seeing BMW engines as small as 1.6 and 1.8 liters so the new 1.5 liter unit might not be too much of a shock, but U.S. buyers are rarely offered anything lower than 2.5 liter straight six engines and latterly 2.0 liter turbocharged fours. The new 3-cylinder engine is effectively half of one of those straight sixes, based around an upcoming line of engines, all of which use a 500cc per cylinder engine capacity.

This means 1.5 liter threes, 2.0 liter fours and 3.0 liter straight sixes. All are designed for optimum fuel efficiency with BMW's usual performance, helped by the use of turbochargers. The new engines will also feature BMW's tried and tested Valvetronic variable valve timing and high pressure fuel injection.

Will the engine appear in the States though? That's a different matter. BMW haven't yet confirmed whether the new threes will appear in the next generation 3-Series range, but BMW's preview video shows the engine mounted transversely so it's likely to make an appearance in the next generation MINIs, which will almost certainly be sold Stateside.

The second generation BMW 1-Series is also expected to be front-wheel drive, so buyers might see the engine in that model too.

Don't think that small capacity means small performance though - the new engines should produce between 40 and 67 horsepower per cylinder, meaning a theoretical minimum 120 horsepower for the base engine. In a MINI, this should make for equivalent performance to today's Cooper. Balancer shafts will ensure good refinement.

We've seen makers like Ford downsizing and offering V6 Ecoboost engines in the Mustang that offer similar performance to the traditional V8s, so it might not be too long before a BMW arrives with half the cylinders buyers are used to without sacrificing the performance they expect, either.

The only production car that currently offers a 3-cylinder engine in the U.S. market is Smart's ForTwo.

[Autocar, Daily Telegraph]