BMW develops lighter, more fuel-efficient gasoline engine

By JENS MEINERS AND KLAUS-DIETER FLORECKE
Automotive News Europe

MUNICH -- BMW will replace its 3.0-liter gasoline engine with what it claims is the world's lightest six-cylinder engine.

BMW engineers have designed a new magnesium-alloy composite crankcase that reduces the assembled engine weight by about 22 pounds to just 355 pounds.

The engine's performance is increased by 12 percent while fuel consumption will drop by 12 percent, says BMW.

Klaus Borgmann, BMW's head of motor engineering, said further development of the automaker's 3-year-old Valvetronic engine management system provided most of the fuel consumption reduction.

The new Valvetronic units deliver 258 hp — 12 percent higher than the current 3.0-liter gasoline units. BMW says that gasoline direct-injection technology can easily be applied, although this is not initially available.

Other fuel-saving features include an innovative water pump using just a tenth of normal power, letting the engine reach optimum temperature more quickly from a cold start.

The new inline six-cylinder engine will debut in the 630Ci coupe and convertible, and subsequently replace current gasoline 3.0-liter engines in the 7 and 5 Series, X3, X5 and Z4.

But BMW will not offer the engine in the 3 Series until the next generation is launched.

BMW has chosen to continue developing inline six-cylinder engines.

Rival Mercedes-Benz abandoned such engines in 1999 in favor of V6 configurations. An inline unit is smoother as it reduces noise, vibration and harshness — but is more difficult to install and more expensive to produce.

The 630Ci will be the first BMW model to get the redesigned 6-cylinder engine.