24 HOURS CENTENARY – PERPETUAL INNOVATION ⎮ Hybrid engines have secured each and every all round win at Le Mans given that 2012. The technologies is now at the heart of the new head class, Hypercar, with as outstanding pioneer the Toyota GR010 Hybrid, winner in 2021 and 2022.
The years among 1975 and 2010 have been marked by the rise of turbochargers with their ability to achieve exceptional energy in small engines.
But, in the early 2010s, issues about global warming resulted in increased awareness amongst car or truck makers. Electric autos were still in their infancy, restricted by the variety and duration of battery recharges. Hybrid cars promised to assure a smooth transition among traditional thermal autos and the electric ones of the future. Toyota had launched its Prius and all the other marques had equivalent projects in the pipeline.
Audi and Peugeot sought to market the technology through competitors in tandem with the arrival of production models. The strategy would forever transform the globe of endurance racing.
In the 1980s, and even as early as 1975, the ACO endeavoured to set guidelines limiting fuel consumption, at some point publishing regulations approving hybrid automobiles in 2012.
Hybrid technologies? What does that imply specifically?
Flywheel vs. battery
To minimize the consumption of fossil fuels (and for that reason CO2 emissions), engineers looked to help the phases in the course of which engines have been unable to operate optimally, like in the course of choose-ups at low revs. They also sought to provide additional power at higher revs to raise the energy exactly where it begins to drop. It became possible either to hold the similar thermal engine and raise the torque and energy with an electric motor, or minimize the displacement of the engine with out losing efficiency.
It was right away clear electricity was a superior way to help heat thermal engines. An electric motor delivers a continuous torque from the first rpm, whilst a thermal engine sees its maximum torque reached among three,000 and four,500 rpm. So an electric motor could help with torque at these speeds, and complement energy beyond that.
Now, how to energy the electric motor and shop power on board for distribution and then assure this storage was recharged for the subsequent acceleration? Two systems emerged as possibilities.
Particular makers focused on a mechanical option, such as the flywheel, driven by wheel shafts up to 40,000 rpm when braking then releasing the stored power in electrical type. In 2011, Porsche presented a 911 Hybrid at the Paris and Geneva motor shows and subjected the car to each and every attainable and imaginable test in the context of each competitors and series production. Nevertheless, the system’s shortcomings swiftly became apparent: the energy output was restricted, the duration of recharging in the course of braking insufficient to preserve superior possible for the subsequent turn and the gyroscopic impact of the flywheel was probably to have an effect on handling.
Other marques, like Audi and Peugeot, concentrated on the batteries. Through braking phases, the electric motor becomes a generator generating electricity stored in batteries. The weight of the batteries matched that of the flywheel, but they proved much a lot easier to set up in a car or truck, and by adjusting their position, it became possible to balance the weight of the car or truck 50/50% among the front and rear axles. As soon as the charge/discharge cycle was mastered, the motor-generator set and the batteries emerged as the excellent option.
ten years of victory for hybrid technology
Ahead of the 2012 FIA WEC season, Audi and Peugeot fine-tuned an R18 e-tron and a 908 Hybrid, respectively, for the championship and the 24 Hours. But Peugeot withdrew its entry at the 11th hour and the face-off did not take place! Audi proceeded to clinch the initially win for a hybrid at the 24 Hours that year, just as it had performed for diesel with the R10 TDI in 2006 and for direct injection with the R8 TFSI in 2000.
Thereafter, the ACO expanded the concept of hybridisation for LMP1 (earlier head class prior to Hypercar) prototypes. By taking into account the quantity of added power supplied by electrical components compared to regular thermal engines, the ACO created authorised consumption scales for each car, controlling them each lap by means of telemetry.
The maximum energy of a set of thermal and electric motors, frequently known as the powertrain, is now restricted to 520 kW (707 hp), of which the electrical element known as MGU-K (for kinetic power) can not exceed 200 kW (272 hp). The manufacturer can then pick out among a Hypercar with a thermal engine alone (Glickenhaus) or a car or truck combining a thermal engine and an electric one particular (Toyota, Peugeot, Ferrari, Cadillac and Porsche). The second group also has the solution of putting the MGU-K on the rear axle or the front wheels, the car or truck then becoming an intermittent 4-wheel drive (selected by Toyota and Peugeot). But the MGU-K can not be triggered beneath 120 kph (190 kph in the rain).
Considering that 2012, only hybrid automobiles have won the race: 3 victories for Audi (from 2012 to 2014) and Porsche (from 2014 to 2017), and five for Toyota (from 2018 to 2022). And this new chapter in the evolution of endurance racing engines is nevertheless becoming written at the 24 Hours…
Images (Copyright – ACO/Archives): LE MANS (SARTHE, FRANCE), CIRCUIT DES 24 HEURES, 2012-2021 24 HOURS OF LE MANS. From best to bottom: the lineage of winning hybrid prototypes with the Audi R18 e-tron quattro (#1), the Porsche 919 Hybrid (#two), the Toyota TS050 Hybrid (#eight) and the Toyota GR010 Hybrid (#7), initially victorious Hypercar, in 2021.