Mercedes F1 W11 Power Unit
Technical analysis: 4 secrets of Mercedes F1 engine
Mercedes F1 W11 engine. First secret: power management.
The greatest sensitivity to power occurs at the beginning of a straight line and not at the end. The traction and acceleration capabilities and the thrust that gives the engine at the exit of the curve are therefore one of the fundamental keys to performance. It is at this stage where having more power, and therefore more thrust and more acceleration, allows the greatest gains in terms of lap time. The top speed at the straight end then becomes a simple consequence.
The graph above shows the positive part of the longitudinal accelerations expressed in G scale (the negative part concerning braking is not an interest of this study). And here we see the most important thing: every time the W11 comes out of a curve and goes into traction it has a higher acceleration peak than the W10 recorded.
Mercedes F1 W11 engine. Second secret: shifts at higher rpm.
Analyzing also the rpm of the engine (lower graph), we notice another interesting thing. In the 2019 coming out from the slow turns the shifts occurred on average between 11,700 and 11,900 rpm, while in this season such regime is higher, between 11,950 and 12,150 rpm. In general, the shifting phase computed by the analysis is always higher of approximately 250 rpm compared to the past year. This would be an singularity: the regulation has a defined fuel flow limitation (100 kg/h) over the 10,500 rpm of the engine, and generally that is where the teams try to have the maximum power of the engine and around which the shifts take place.
So, the question is, how is it possible to fullfill the oil limitations by shifting at so high rpm?
Mercedes F1 W11 engine. Third secret: deactivation of pistons?
It seems from some rumors that Mercedes”cuts” the power to some cylinders to better prepare the bend exit and have more traction, while decreasing consumption.
This operation would allow to manage in a better way the wear of the rear tyre, but above all to improve the adhesion in the distance and in the first moments of acceleration leaving the turns.
The second positive effect of this system is a slight reduction in consumption. As mentioned, by deactivating the cylinders it is possible to operate the engine at reduced displacement, keeping active fewer cylinders but at a higher load. As a result, the throttle body remains more opened with the same partial power output, so that the pistons can ‘spend much less energy to suck the fuel mixture into the chamber of combustion: are then limited the pumping losses.
Mercedes F1 W11 engine. Fourth secret: less mechanic lubrification.
The MGU-H works during the driving phase in a more intense way and, in fact, acts on the compressor, further increasing the air pressure for combustion. Its use in a more intense way would also imply a greater use of electricity from the battery pack and this would also explain the appearance of clipping at the straight end. This would also “match” with how much rumored in the paddock about lubricants, namely that a work (huge) on the reduction of friction and oils produced by Petronas allows the Mercedes power unit to use even less lubricant to precisely lubricate kinematics than before, and to take advantage of the share saved to inject it into the combustion chamber and obtain a more efficient and more powerful combustion. Together with more work of the compressor at low car speeds, the balance of combustion through a supplementary injection of oil would close the circle and would also be compatible with the white smoke noted in qualifying on Saturday in Budapest, seen, also, always in the phases of traction in exit of curve.