Best of Both Worlds-- AVL developing variable-compression engine

A VL List GmbH Chairman and Chief Executive Helmut List believes his highly specialized company's engineers have an answer to the ever-growing gap between what Europeans and U.S. customers want from an engine: an advanced new engine design that combines the best attributes of diesel and gasoline engines. Mr. List calls the new engine concept the "Fully Flexible Internal Combustion Engine."

Mr. List says the Fully Flexible Internal Combustion Engine idea can address what AVL sees as a clear difference between the powertrain demands of divergent global markets - the opposite "poles" being represented mainly by the U.S. and Europe.

He says that in Europe powertrain development is dictated primarily by fuel prices that are three times that of the U.S. A secondary, but equally important difference, is emissions regulations. He says the U.S. is concerned largely with reduction of oxides of nitrogen (NOx) and hydrocarbons (as well as particulates), while the European Community is more intent on cutting carbon dioxide (CO2) emissions. In essence, this means European automakers - and customers - have focused development on highly fuel-efficient diesels, yet the U.S., because of cheap fuel and customer reluctance, continues to shun the diesel.

The Fully Flexible Internal Combustion Engine, explains Mr. List, could bridge this gap by combining the best qualities of the diesel with the gasoline engine. He says the Fully Flexible Internal Combustion Engine presents:

n Overall fuel economy close to today's most advanced diesels.

n No need for complex aftertreatment technology (a guaranteed requirement if diesels are to meet coming U.S. Tier II and California emissions standards).

n No smoke (a longtime diesel bugaboo).

n Insignificant engine-out emissions.

Mr. List says the Fully Flexible Internal Combustion Engine will be designed to run as a spark-ignited engine "in the upper power range and under compression ignition at light load."

As one of the industry's most noted powertrain research and development operations, AVL, says Mr. List, devotes an inordinate amount of its operating revenue - roughly 10% - to ongoing powertrain and combustion research. The industry has rewarded AVL for this philosophy: AVL's annual rate of growth for the last five years has been more than 20%.

If AVL's new engine can take hold, that's good news for OEMs struggling to adapt one engine or engine family for a variety of global markets. It's good news for suppliers, too, because Mr. List claims the advanced control strategies required to make the Fully Flexible Internal Combustion Engine work will require twice as many sensors and actuators as today's most advanced spark-ignited gasoline engines that employ direct injection (DI). A DI gasoline engine, he explains, employs five or six distinct actuators - and AVL's Fully Flexible Internal Combustion Engine needs 10 to 12 actuators.

AVL's new engine design also underscores an increasing powertrain industry need for advanced calibration and control modeling. It has developed its new computer-aided management for engine optimization calibration strategy to address these needs and to integrate other development functions.

Mr. List calls driveability optimization "one of the most complex areas" of powertrain development - again, because of the differences between U.S. and European/Japanese driver preferences. AVL has quantified the primary differences:

n In the U.S, he says, drivers covet cruising ability and comfort from their drivetrains.

n Europeans prefer seamless throttle "tip-in" and gearshift.

n Japanese drivers value calm idling and vibration-free operation.

"If it (the Fully Flexible Internal Combustion Engine) works the way we think it will," says Mr. List, there will be a 20% efficiency improvement over standard gasoline engines, and "there should not be a large cost difference.

"It's a concept at this stage," says Mr. List of the Fully Flexible Internal Combustion Engine. "But I think it's very feasible."