Diess: Engine Downsizing at VW Stops at 1.0 Liter

The environmental benefits of using ever-smaller turbocharged gasoline engines can start to reverse when their displaced falls below about 1.0 liter, says Volkswagen brand chief Herbert Diess.

"The trend of downsizing is over," Diess told reporters last week at the launch for the updated VW Golf hatchback. Noting that small engines often don’t perform as well during real-world conditions as they do in laboratory tests, he says tailpipe emissions “tend to go up” as engines get smaller than 1 liter.

VW will continue to use its current 1.0-liter 3-cylinder gasoline engine in small cars such as the Up and Polo. But Diess says there are no plans for smaller engines.

Diess adds that diesel engines that displace less than 1.6 liters don’t make economic sense without heavy tax incentives. He notes that costs likely will increase as emissions regulations become more severe.