In 2014 Porsche entered the FIA World Endurance Championship (WEC) using in its 919 Hybrid the most innovative powertrain concept on the entire grid: a four-cylinder turbo combustion engine connected to the rear axle, a recovery system of energy from exhaust gases, lithium-ion batteries to store energy and supply it to an electric motor coupled to the front axle and a complex hybrid propulsion management system.
With this, the German house set new standards in the WEC, the most demanding from a technical point of view. In 2015, which was their second year racing, the team was rewarded with success: a double at the 24 Hours of Le Mans and both Constructors and Drivers titles. And this year he already achieved a new victory at Le Mans, although it is true that it was due to the technical problem that Toyota had.
The world champion engine, with a displacement of just two liters, is the most efficient combustion engine Porsche has ever built. It stands out for its compact design and has also become a trendsetter, as the new four-cylinder turbo engine in the Porsche 718 Boxster benefits from the technology and knowledge gained from racing mechanics. This is realized, for example, in the space between cylinders, in the short piston stroke and in the central direct fuel injection.
The four-cylinder in the 919 is not a flat engine like the new generation turbochargers in the 718 Boxster, but rather has a "V" construction with a 90 degree angle. The small powertrain, with which Porsche won its 17th overall victory at the 24 Hours of Le Mans last year, had more than 500 horsepower at the time. However, for 2016 regulations require a lower amount of energy from the fuel used in each lap and the flow of gasoline has been reduced in all prototypes. For the Porsche racing engine this means a loss of 8% of fuel and consequently the power drops below 500 horsepower. Together with the electrical energy taken from the two energy recovery systems (that used by braking the front axle and that of the exhaust gases), which supply the electric motor located on the front axle, the total propulsion system of the Porsche 919 Hybrid now gives about 900 horsepower.
The regulation for the highest category of the WEC (LMP1) obliges manufacturers to use hybrid propulsion systems. It also establishes a direct link between the sports performance of the prototypes and their energy efficiency. Simply put, this means that a large amount of energy must be used from recovery systems.
However, that implies a proportional reduction in the amount of fuel allowed for each lap. The WEC gives engineers a great deal of freedom in the hybrid drive concepts they can employ. Teams can choose between diesel and gasoline, naturally aspirated or turbocharged engines, various displacements and one or two energy recovery systems. This configuration puts the focus on innovations, which will have a huge impact on future series-production sports cars and which is the main reason that prompted Porsche to return to the world of racing at the highest level.