GM’s new 3-cylinder diesel slashes Opel Astra's CO2

General Motors has added a three-cylinder diesel to its new family of global modular gasoline and diesel engines.

The new 1.5-liter unit debuted in Europe late last year on compact models from former GM subsidiary Opel/Vauxhall. PSA Group bought Opel/Vauxhall from GM in 2017, but some Opel/Vauxhall models still use GM platforms and powertrains.

The 1.5-liter diesel offers 105 hp and 122 hp, down from 136 hp in the 1-6-liter four-cylinder unit it replaced.

Emissions were reduced by about 20 percent, with the most economical 105-hp variant rated at 90 grams per kilometer of CO2 under the NEDC homologation cycle, according to a report lead by former GM engineer Roberto Golisano that was presented at the annual Vienna Motor Symposium.