The BMW M Hybrid V8 is powered by the P66/3 eight-cylinder turbo engine with an additional electric drive.
14-07-2022 18:27 - MOTORSPORT
Both for reasons of time and with a view to sustainability, which is playing an increasingly important role not only in the automotive industry in general but also in motorsport, it was not an option to design a completely new engine at the drawing board and manufacture it from scratch at great expense. Consequently, the question was which proven racing engine best meets the high requirements and specifications of the LMDh regulations. The choice fell on the P66/1 eight-cylinder naturally aspirated engine that was used in the BMW M4 DTM in the 2017 and 2018 seasons. One of the things that spoke in its favor was that it could be used as a fully load-bearing component in the BMW M Hybrid V8 without an additional subframe in a monocoque chassis and, even after its conversion to a hybrid turbo engine, best met the requirements of the regulations.
In the first phase, the P66/1 DTM naturally aspirated engine was essentially rebuilt by adapting two turbochargers and adjusting the crank mechanism to form an interim unit with the designation P66/2. The focus was on durability, increased performance and temperature management of the engine. To this end, the P66/2 completed many test units on the test bench, including complete racetrack simulations. In the next step, the P66/3 racing engine was created with, among other things, two turbos, adjustments to the special requirements of the Dallara chassis, final exhaust system, oil tank, wiring and integration of the high-voltage environment. Furthermore, the cylinder block and cylinder heads were recast in the BMW Group foundry in Landshut (GER) and the injection system was redesigned for direct injection. At the same time, the electric motor was tested and integrated by engineers, who already had a lot of experience with electric drives from the Formula E project. The unit that forms the hybrid drive in the vehicle consists of an electric motor, inverter and high-voltage battery. There is a separating clutch between the electric motor and the combustion engine, which enables purely electric driving – for example in the pit lane.