Renault F1 analysis: The efficiency race

At the end of 2013 the FIA Formula One World Championship bid farewell to its normally aspirated V8s and embraced brand new Power Units that combined a hybrid V6 turbo engine with two energy recovery systems – the MGU-K that works under braking, and MGU-H which harvests energy at the exhaust. Monza’s 2014 race offered an ideal opportunity to compare and analyse the performance of modern low downforce-spec F1 cars with their previous counterparts.

The recent Grand Prix emphasised an important point: the 2014 regulations have greatly enhanced the cars’ efficiency while maintaining – and even increasing – their level of performance.

We take a look at the main gains.

1. A two-second gain in a single year

2013 saw F1 cars fitted with normally aspirated V8s delivering around 800bhp (that’s 590kW without the extra 60kW provided by the KERS). Monza’s speed traps recorded single-seaters clock around 340kph, with pole-sitter Sebastian Vettel posting a lap of 1:23.755 in qualifying aboard his Infiniti Red Bull Racing-Renault. A year later the fastest Q3 time was 1:24.109, achieved with a car weighing 50kg heavier – a 1.8secs deficit – and using harder tyres. Once these differences have been accounted for and the times corrected, this year’s lap represents a two-second gain over the course of 12 months.

2. Fuel consumption down to 1.9kg per lap

The 2014 regulations also brought another revolution with a 35% reduction in the amount of fuel permitted for each race (100kg against 150kg last year). It’s been made possible thanks to the V6 engine’s high degree of hybridisation: 20% of the power is now electric and comes from the energy recovered under braking and harvested at the exhaust. The average Monza consumption rate therefore went from 2.5kg per lap in 2013 to under 1.9kg a lap this year. With the same mass, the corrected 2014 time is faster.

3. An F1 car’s energy source distribution

— 2013: The vast majority of energy available came from the 160kg of fuel used by the car. Power generated by fossil energy and transferred to the wheels reached 30%, while the remainder escaped in the air. A single KERS unit also ensured the share of electric power remained quite limited.

— 2014: With a 100kg restriction in fuel mass, the share of electric power has grown significantly. A greater percentage is now transferred to the wheels, which vastly improves the overall energy efficiency. Electric energy is much more important (4MJ) than it was last year. It comes from two different sources: braking and the exhaust.

4. Better energy efficiency

In 2013 an F1 car’s efficiency was rated at 30%, which has increased to 40% in 2014. This has been made possible by reducing the internal combustion engine’s displacement (and amount of friction), the introduction of a turbocompressor, and cutting the number of revs (from 18,000 to 13,000). The efficiency of a car fitted with an internal combustion engine cannot exceed 50%. Only a fully electric engine can achieve a much higher efficiency. To do so, however, requires 25 tons of batteries!

Additional stats and facts

— 30% fuel mass reduction between 2013 and 2014.
— 10 points: the efficiency improvement of an F1 car between 2013 and 2014.
— In qualifying, the 25kg battery delivers an extra 10% of energy, which amounts to 200g in fuel.
— While overtaking during the race, Daniel Ricciardo’s Infiniti Red Bull Racing-Renault reached 362.1kph, smashing the 2013 top speed by an impressive 20kph.