Mercedes bosses are poised to decide whether the firm’s next-generation of downsized engines will be three- or four-cylinder units, according to a senior company source.
The new engines – sized between 1.4- and 1.6-litres will be used in both the next-generation A/B-class replacement and the C-class range.
Although BMW has already committed itself to using a thee-cylinder engine in the next-generation 3-series, Mercedes bosses are hesitating to follow because of what they say are the extra costs and complexity involved.
One senior source told Autocar that using a three-cylinder engine (most likely engineered as half of Mercedes V6 unit) "was relatively expensive to optimise".
This means that extra, potentially costly, measures had to be employed with the to reduce the noise, vibration and harshness that is typical of a three-pot layout.
As well as extra sound deadening, more sophisticated engine mounts and selective stiffening for the bodyshell would all be needed, adding to the costs of what would be entry-level models for the brand.
According to the source, the cheaper alternative is for Mercedes to look for a partner who could supply a more conventional four-cylinder unit, which Mercedes could then modify with its own direct injection and turbocharger.