MERCEDES AMG HIGH PERFORMANCE ENGINES
All current Formula 1 cars use 2.4-litre, non-turbocharged V8s. The new Mercedes 1.6-litre V6 engine is a massive departure from current engine practice
of technical partner, Petronas, revealed, the company is working toward mass and power density targets in an effort to maximise performance. However, unsurprisingly, the
rules have shifted the emphasis even further toward energy recovery. Engines are allowed a single turbocharger and a mechanical drive can be taken off the turbine shaft to generate electricity, with significant controls in the rules regarding turbo design and position. As
ENERGY RECOVERY SYSTEMS M
ercedes was quick to take up the challenge of Kinetic
Energy Recovery Systems (KERS) when they appeared on the scene in 2009. Opting for an electro-mechanical system, the company developed its own system from scratch in house, with help from outside specialists. With the new energy recovery rules on the horizon, this approach is now serving them well.
The original system used in 2009 was the best and most reliable KERS to see action that season. It was also the
first system to be used on a race-winning car. By the end of the year the teams, most of who had not managed to exploit the technology successfully, all unanimously agreed that it would not be used in 2010. So the Mercedes system was shelved, but not before the technology was put on the dynos at the Brixworth factory once more and thoroughly interrogated to capture as much data as possible. At the factory, there was a
belief that it would be back in two or three years time, but
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www.racecar-engineering.com • February 2012
even they were surprised when it came back just two years later, in 2011. That previous work and banked knowledge then came into its own, and the new system has improved the round trip efficiency of the system from 75 to 80 per cent. It has also been laid out in the car differently. The 2009 system had the batteries in one sidepod and the control unit in the other, but re-packaging has allowed them both to be installed under the fuel tank within the monocoque. This frees up the bodywork for aerodynamics
and protects the batteries in an accident.
In 2009 there was much talk
of the batteries having a short life and being renewed every race. In reality, Mercedes has found they outlast the life of the engine, while still delivering good efficiency. It is only other service items within the battery pack that forces them to be replaced. The secret, according to Cowell, is good management of the batteries, by maintaining their charge levels within an optimum band and keeping their environment cool.
“a maximum fuel flow of 100kg/h… above
10,500rpm”
Cowell points out, ‘If you allow a group of Formula 1 engineers to turbocharge an engine, and you don’t put technical constraints on it, you’ll end up with a very big project. You’ll have a gas turbine on the back end and it’ll be an external combustion engine.’ The regulations therefore
dictate a single-stage compressor and prohibit any variable geometry on the hot exhaust side. So, no variable nozzle technology of the type found on road cars on the turbine,
although the same area on the compressor seems to be free. The link between the turbine and the compressor must be a common shaft, with no step ratios, parallel to the crankshaft axis and no more than 25mm from the centreline. ‘Hence the location of the
compressor and turbine housing,’ says Cowell, ‘so we’re all doing the same. If we had complete freedom we would have two turbochargers for the two banks but then we would have doubled
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