Mercedes development chief Thomas Weber has said he expects to see a big trend towards smaller engines in coming years, in response to higher petrol prices and tougher emissions laws.

He also told the dpa-AFX news agency at the Detroit motor show that diesel engines were already downsizing, but that there is much more room for petrol engines to go in the same direction.

"We will strongly force the trend in downsizing," said Weber, adding that smaller engines used in the A- and B-class, would also be used in the C-class. He said that the trend towards larger, more powerful engines that has been taking place recently would be sharply reversed.

Weber said Daimler is aiming to reduce engine cylinder size, and, for example, add turbocharging to boost performance. "The first step is definitely small four-cylinder engines with turbochargers, but why not also then move on to a turbocharged three-cylinder engine. It is completely clear that we will consider such solutions."

Weber said that although Daimler could develop such engines itself, it is still talking to potential partners about a joint entry-level diesel engine, with 1.6 or even 1.4 litres capacity.

Rival German automaker VW last year introduced a turbocharged and supercharged 1.4-litre petrol engine.