BMW V12 engine: From aircraft to saloon car

Novan Iman Santosa The Jakarta Post Serpong, Banten

How many people are aware that the giant automotive company BMW started its business producing engines for aircraft? This fact is far removed from many people's impressions of this manufacturer of luxury cars and motorcycles.

In 1918, the company produced its first V12 engine for an airplane which crossed the Atlantic ocean in 44 hours.

"The engine was among the most sophisticated of that time," said BMW Indonesia technical trainer, Denny Hermawan during a media technical workshop at BMW National Training Center in Serpong, Banten.

But it was not until 1987 that the company decided to develop another V12 engine, this time for its Series 7 flagship saloon car. The V12 engine has undergone constant improvements ever since.

The third generation of BMW V12 engine was launched in 1994, while in 1999 a special V12 engine was developed for Le Mans super sports car.

The latest edition of the V12 engine was introduced in 2003 and called the N73 new generation engine, with a capacity of 5,972 cc and 60-degree configuration.

The engine produces maximum power of 438 horsepower (hp) at 6,000 revolutions-per-minute (rpm) and maximum torque of 600 Newton meters at 3,950 rpm.

The engine allows BMW 760Li, the company's flagship sedan, to reach the speed of 100 kilometer per hour (kph) in 5.5 seconds and achieve a maximum speed of 250 kph.

"Actually the engine is powerful enough to be faster but there is a regulation limiting speed limit in Germany," said Denny.

The N73 engine uses all the latest technology to make it a more powerful, cleaner, and more fuel-efficient engine.

The engine block is manufactured from lightweight aluminum reducing the sedan's weight from 300 kilograms, in the earlier model, to 280 kilograms -- giving it a better power to weight ratio.

Its direct-injection system protrudes deep into the combustion chamber creating a more homogeneous mixture of fuel and air.

The N73 engine is the first to apply the direct-injection system. The V8 N62 engine for BMW 735Li and N42 engine for 318i do not use this technology.

There are four valves for each cylinder, two each for the intake and exhaust, the valves' openings are controlled by Bi- VANOS and Valvetronic technologies.

Bi-VANOS controls the valves' opening-time while Valvetronic controls the intake valves' opening, which varies from 0.3 millimeters (mm) to 9.85 mm. Earlier engines have a set opening of 10.3 mm.

"BMW's engineers currently only apply Valvetronic technology to the intake valves, while Bi-VANOS is applied to both intake and exhaust valves.

"Perhaps, someday, engineers will also apply Valvetronic to the exhaust valves," said Denny.

Meanwhile, BMW Indonesia's technical advisor of service operation Owen Riley said that the 12-cylinder engine was a smooth running engine.

"With more cylinders, there will be more combustion during a cycle, giving it more power as well as making it smoother," he said.