The particular forte of this valve management concept is that valve lift and the intake valve opening periods are modified within fractions of a second to current power and performance requirements.

To provide this effect the camshaft does not act directly on the valves via a rocker arm, but rather incorporates a further lever in between, where the pivot point is adjusted by an eccentric shaft driven by an electric motor.

So depending on the position of the pivot lever, intake valve lift is varied infinitely between 0.2 and 9.5 millimetres (0.008 - 0.374.''). And the entire process of switching over from minimum to maximum valve lift takes just about 300 milliseconds.

This technology provides the same effect that otherwise requires adjustment of a throttle butterfly within the intake manifold of a conventional engine. Variable valve management thus renders throttle butterfly control superfluous and avoids the disadvantages of undesired air swirl in the intake manifold particularly when running under half-load. And while the new normal-aspiration power unit of the MINI Cooper still incorporates a throttle butterfly, the throttle butterfly in this case serves only emergency and diagnostic functions and otherwise remains fully open under normal operating conditions for a smooth and dynamic flow of the fuel/air mixture. The underpressure required by the brake servo, finally, is generated by a vacuum pump driven by the outlet camshaft.

In addition to variable management of valve lift on the intake side, valve timing on the intake and outlet side are spread apart individually as a function of engine speed. Valve timing is therefore also infinitely controlled, with a spread range of 70 degrees on the intake and 60 degrees on the exhaust camshaft.

Again, this entire adjustment process requires a mere 300 milliseconds when needed, such an extremely high reaction speed being ensured by way of a high-performance 32-bit computer networked with the engine management system as a whole.

Interacting with one another, variable valve lift and engine speed-related camshaft management serve to optimise the torque and power curves. Even at low engine speeds, therefore, the power unit of the new MINI Cooper develops high torque, while at high engine speeds it delivers a lot more power than conventional engines.

A further advantage is that both technologies help to significantly reduce fuel consumption: Depending on the route, fuel consumption is down by up to 20 per cent and in the EU test cycle the car's fuel consumption has been reduced by approximately 12.5 per cent.

Yet a further advantage is the ability of the engines to run smoothly and reliably on any grade of fuel quality. This is indeed an essential criterion for a global player like MINI. This versatility is also ensured by the single ignition coils masterminded by the engine's electronic control unit for optimum ignition voltage on the spark plugs in each cylinder. Anti-knock control, finally, enables the engine to run on various fuel grades between 91 and 98 octane.

The 1.6-litre normal-aspiration engine develops maximum output of 88 kW/120 hp at 6,000 rpm and has a top engine speed of 6,500 rpm. Torque is a significant 140 Nm or 103 lb-ft at just 2,000 rpm, with the engine reaching its peak torque of 160 Nm or 118 lb-ft at 4,250 rpm. With its wide useful range of engine speed, the compact power unit therefore combines optimum driving pleasure with superior fuel economy at all times.



Turbocharged power unit with twin-scroll turbocharger and direct petrol injection

The turbocharged version of the new 1.6-litre four-cylinder featured in the MINI Cooper S offers even more impressive performance data: Maximum output is 128 kW/175 hp, a figure which certainly sets the standard for an engine of this size reaching its maximum power at 5,500 rpm.

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