Mercedes is working towards having stop-start technology fitted on all its engines, according to one of its senior engineers.

Christoph Spengel, head of engine development for Mercedes' latest six-cylinder diesel, said: “I won’t name a year when we will achieve this goal, but it is a priority for Mercedes. We are pushing hard, and there is the possibility to jump ahead of BMW.”

Mercedes will introduce stop-start for the first time on a four–cylinder petrol engine, the 181bhp turbocharged E200 CGI, from the middle of next year, but engineers aren't happy with the way the system works on automatic models yet.

By 2011, however, Mercedes expects to have overcome the problems of fitting stop-start to automatics. The technology will then be rolled out on all V6 and V8 models, which have automatic gearboxes fitted as standard.

“Fitting the system to any engine and gearbox is not a problem, we can get reliability quite easily,” said Spengel. “Achieving the smoothness of the start is the real problem. Engaging the starter takes a little time, and then firing the engine takes a little time, and it is important that our system does not disturb the driver.”