BMW is renowned for having some of the greatest and most modern engines in the business but when it comes to one of the latest innovations in powertrain technologies BMW says it will take a "wait and see" stance. The technology we’re talking about is homogeneous charge compression ignition (HCCI), a process that works by achieving combustion of petrol with only compression of the air-fuel mix rather than using a spark plug.

Both GM and Mercedes have already started testing the engine in prototypes with plans to eventually introduce it into their production cars but BMW is still sitting on the fence. Speaking with, BMW’s manager for Energy Integration Systems Axel Rücker explained that no development of HCCI had been started because current “diesel engines still offer potential for cleaner and more economical developments.”

The technology definitely shows promise, especially for markets where diesel is still unpopular. Mercedes’ prototype HCCI engine, dubbed DiesOtto, developed an amazing 238hp (175kW) and 400Nm of torque from a small 1.8L petrol engine. Another prototype being tested by MIT is said to improve fuel-efficiency by up to 25%. BMW's diesel engines are already renowned for their performance and refinement but this new technology could level the playing field among other manufacturers.