March 26, 2023 2:49 pm

24 HOURS CENTENARY – PERPETUAL INNOVATION ⎮ Hybrid engines have secured just about every general win at Le Mans considering the fact 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 amongst 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 vehicle suppliers. Electric automobiles were still in their infancy, restricted by the variety and duration of battery recharges. Hybrid cars promised to make sure a smooth transition amongst traditional thermal automobiles and the electric ones of the future. Toyota had launched its Prius and all the other marques had related 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, sooner or later publishing regulations approving hybrid vehicles in 2012.

Hybrid technologies? What does that imply precisely?

Flywheel vs. battery

To decrease the consumption of fossil fuels (and hence CO2 emissions), engineers looked to assistance the phases through which engines have been unable to operate optimally, like through choose-ups at low revs. They also sought to provide additional power at higher revs to enhance the energy exactly where it begins to drop. It became possible either to maintain the similar thermal engine and enhance the torque and energy with an electric motor, or decrease the displacement of the engine without having losing overall performance.

It was instantly clear electricity was a excellent way to help heat thermal engines. An electric motor delivers a continual torque from the first rpm, when a thermal engine sees its maximum torque reached amongst 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 retailer power on board for distribution and then make sure this storage was recharged for the subsequent acceleration? Two systems emerged as possibilities.

Particular suppliers focused on a mechanical answer, 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 just about every probable and imaginable test in the context of each competitors and series production. On the other hand, the system’s shortcomings speedily became apparent: the energy output was restricted, the duration of recharging through braking insufficient to retain excellent prospective 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. In the course of 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 vehicle, and by adjusting their position, it became possible to balance the weight of the vehicle 50/50% amongst the front and rear axles. As soon as the charge/discharge cycle was mastered, the motor-generator set and the batteries emerged as the perfect answer.

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 come about! 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 extra power supplied by electrical components compared to regular thermal engines, the ACO created authorised consumption scales for each car, controlling them each lap by way of telemetry.

The maximum energy of a set of thermal and electric motors, generally referred to as the powertrain, is now restricted to 520 kW (707 hp), of which the electrical element referred to as MGU-K (for kinetic power) can not exceed 200 kW (272 hp). The manufacturer can then decide on amongst a Hypercar with a thermal engine alone (Glickenhaus) or a vehicle 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 vehicle then becoming an intermittent 4-wheel drive (selected by Toyota and Peugeot). But the MGU-K can not be triggered under 120 kph (190 kph in the rain).

Considering that 2012, only hybrid vehicles 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 getting written at the 24 Hours… 


Pictures (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.

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