In a few weeks, the extensive testing phase will begin for the BMW M Hybrid V8, with which BMW M Motorsport will fight for overall victory in the IMSA GTP class of the WeatherTech SportsCar Championship in 2023. Before the rollout, the project had already reached an important milestone: the activation of success of the hybrid car after installation on a test car at the end of June. The BMW M Hybrid V8 is powered by a P66/3 eight-cylinder Turbo engine with an additional electric drive. The basis of the combustion engine is the DTM unit that was used in the BMW M4 DTM in 2017 and 2018. It was largely adapted to the high demands of the LMDh hybrid drive in two conversion phases.
P66/3 eight-cylinder hybrid
Even before the BMW Group Management Board gave the green light for BMW M Motorsport to enter the LMDh category in June 2021, Ulrich Schulz, Head of Powertrain Design at BMW M Motorsport, and his team began to evaluate which racing engine it would be better. A conversion to a high-performance hybrid drive is worthwhile. Both for reasons of time and for the sake of sustainability, which plays a more important role not only in the automotive industry in general but also in motorsport, designing a completely new engine on the drawing board and producing it at high cost from scratch. it’s not an option. So, the question was which race engine was proven to meet the high requirements and specifications of the LMDh regulations.
fully bearing part in the BMW M Hybrid V8
The choice fell on the P66/1 eight-cylinder 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 full load carrier in the BMW M Hybrid V8 without a small frame. extra on a monocoque chassis and, even after its conversion to a hybrid turbo engine, it met well. regulatory requirements.
“During the evaluation phase, we also looked at the P48 four-cylinder engine from the BMW M4 DTM and the P63 turbocharged eight-cylinder engine from the BMW M8 GTE, but durability issues with the P48 and the heavy weight of the P63 spoke against it.” , Schulz explains the decision in favor of the P66 engine. “It is a great advantage that we were able to use materials such as steel and aluminum that were still available from the BMW Formula 1 era for the engine base and for individual components – for example shafts, housings and small parts.
This saved a lot of time and money and was therefore efficient and sustainable. Efficiency is important in this project because the time from gun start to the first race at Daytona 2023 is very tight. Replacing the standard P66/1 engine first with a bi-turbo and then, in cooperation with its electric car counterparts, a hybrid car was very difficult. Thanks to the expertise, good cooperation and high motivation of all departments, we were able to successfully complete the fire of the entire vehicle unit a few weeks ago. In our opinion, nothing prevents the experimental operation.
The cylinder block and cylinder heads are refreshed
In the first phase, the expected P66/1 DTM engine was fundamentally changed by modifying the twin turbochargers and modifying the crank mechanism to create a temporary unit named P66/2. The focus was on durability, increased performance and thermal management of the engine. To this end, the P66/2 completed multiple test units on the test bench, including a full race simulation. In the next step, the P66/3 racing engine was designed with, among other things, two turbos, modifications to the special needs of the Dallara chassis, the final exhaust system, fuel tank, wiring and high environmental integration- voltage. In addition, the cylinder liners and cylinder heads were redesigned at the BMW Group plant in Landshut (GER) and the injection system was redesigned for direct injection.
At the same time, the electric motor was tested and assembled by engineers who already had a lot of experience with electric drives from the Formula E project. The unit that makes up the hybrid drive in the car consists of an electric motor, an inverter and a high-voltage battery. There is a clutch that separates between the electric motor and the combustion engine, which enables electric driving – for example in pit lane. The first combination of both car components took place when they were installed on the car at the end of June. The first fire of the hybrid system was successful. This will be followed by a publication in Varano de Melegari (ITA) at the end of July. The intensive test phase begins immediately afterwards.
Technical data on the P66/3 BMW M Hybrid V8 engine.
|selection||Four-stroke bi-turbo engine in V design|
|to move||3,999 cc|
|number of cylinders||of the 8th|
|cylinder construction||Cylinder block and cylinder head in cast aluminium, cylinder liner as steel layer using LDS process.|
|V angle||90 degrees|
|drilling holes||93 mm|
|cylinder position||102 mm|
|valves per cylinder||4|
|rotation speed||Maximum 8,200 rpm|
|Performance (Principles)||about 640 hp|
|torque||about 650 Nm|
|needle||High pressure direct injection at 350 bar|
|fuel system||Dry sump system with six-cell fuel cleaning pump and fuel tank|
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