Mercedes 2014 power unit - side view 17 April 2014
If we compare the component installations on Mercedes' and Renault's power units, it is easy to see how different their concepts are. One of the fundamental requirements of a turbocharged engine is to reduce the temperature of the charge air (the blue part of the turbo) - the cooler this charge air is, the more power the engine will produce. Unlike Renault, Mercedes have separated the hot side of the turbo (in red) from the cold side (in blue) and have the MGU-H mounted in the 'V' of the engine between the two parts of the turbo. This has two main advantages: firstly, the heat transfer between the two parts of the turbo is minimised, so less cooling is required to keep the charge air temperature down (or if the same cooling capacity is used, the charge air temperature will be lower, giving more power to the rear wheels). Secondly, having the MGU-H mounted between the two sides of the turbo could allow Mercedes to have either or both sides working through one-way clutches, making the complete unit more efficient. Basically the exhaust gases coming out of the engine on the hot side of the turbo only ever have to drive the cold side of the turbo and or the MGU-H, creating electrical power from this component and feeding it directly to the MGU-K. The MGU-H only ever has to drive the cold side of the turbo, increasing the charge air pressure, thus reducing turbo lag and increasing power. The potential advantages of the Mercedes concept could be significant over the course of the season, especially as retro fitting a similar solution will be very difficult for the other power unit manufacturers.