The A-Class is being launched with a range of four-cylinder petrol and diesel engines, including a 1.5-litre diesel sourced from Renault-Nissan. Its largest motor is the 2.2-litre diesel in the A220 CDI.
An even more potent version of that engine will reach dealers early in 2013, but Mercedes' A-Class development boss, Jorg Prigl, revealed to What Car? that with work, the car could accept even larger six-cylinder powerplants.
'This platform has been designed for four-cylinder engines,' he said, 'because there are compromises in weight and so forth that come with six-cylinder engines, and it does not make any sense to have those right across the model line-up.
'However, if at some point the market requires that the car should be offered with a six-cylinder engine, then we could find a way to make it work.'
The deciding factor in whether the A-Class gets the six-cylinder engines is not likely to be sales in Europe, but in markets where fuel economy is less of an issue, such as China, North America (where the model as a whole has yet to be confirmed for sales) and Russia.
Russian or Chinese markets could accommodate the A-Class with six-cylinder engines
Prigl also said that Mercedes has no plans to follow the strengthening trend for downsized engines in family hatchbacks. Ford now sells a 1.0-litre three-cylinder Focus and the next version of the Volkswagen Golf, due in the autumn, is likely to be offered with a similar configuration of engine.
'For some manufacturers there is a communications benefit through having a three-cylinder engine,' said Prigl, 'but I believe with this generation of four-cylinder engines we will deliver a good level of performance in the A-Class.'