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Image: - Jens Kriese, Project Leader, BMW (TOP) and Bruno Weber, Project Manager, PSA Peugeot Citroën

Over the past four years, BMW and PSA have won this category with their jointly developed and produced 1.6- litre turbo engine. However, in the past 12 months, BMW has launched its own, further developed version of the multiple award-winner, and it’s this powerplant that has taken the honours in 2011.

Central to this enhanced unit is the adoption of fully variable valve management. The throttle-free load control technology – based on the Valvetronic system used in other BMW engines and highly unusual in this compact segment – optimizes the engine’s responses and, at the same time, makes for a significant reduction in fuel consumption and emissions.

Within fractions of a second, the valve management adjusts the stroke and opening period of the intake valves to the amount of output required, with the camshaft acting on the valves through an additional intermediate arm, and not directly through the cam follower. The pivot point of this additional intermediate arm is infinitely adjustable by an eccentric shaft controlled by an electric motor.

The result is an engine that brings fully variable valve management, turbocharging and 120 bar petrol direct injection together for the first time in a Mini. The engine was first seen in the Countryman Cooper S and has now been rolled out across the Mini range. The fuel economy of the 184bhp motor on the EU combined cycle is around 9% better than its predecessor’s.

When it came to the judging, the new unit was up against some talented rivals. Fellow downsized turbos from Alfa Romeo and Ford both scored well in Europe, but failed to match the BMW’s consistent scoring in all regions. That could change in the future when the Alfa and Ford units are rolled out across multiple continents.

“It’s the energetic heart of one of the world’s friskiest and most funloving cars,” said jury member, Frank Markus from Motor Trend, summing up the Mini engine’s appeal.