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BMW P84/85 Engine

By BMW WilliamsF1 Team
February 2 2005

BMW P84/85 Engine

The BMW Formula One engine for the 2005 season is not called P85, as one might expect, but comes with the model designation P84/5. “The name”, says BMW Motorsport Director, Mario Theissen, “reflects the fact that the engine draws on the concept of the previous year’s P84 unit but in a configuration that is in keeping with the modified requirements.”

These requirements include a further doubling of the engine’s running distance, the powerplant now has to last for 1,500 kilometres. That signifies a quadrupling of the distance covered in comparison with 2002. In 2003, for the first time, the same engine used in qualifying had to be used in the race as well. 2004 saw the introduction of the one-weekend engine rule. In 2005, engines cannot be replaced until they have covered a distance of two Grand Prix weekends.

Between Friday and Sunday, the engines have to tackle extremely diverse disciplines. During the free practice sessions, which are used for set-up work and tyre selection, the teams will now increasingly focus on sparing the engines. Theissen: “That can be achieved in two different ways: driving fewer laps or reducing engine speed. We don’t want to drive less because that would cost us valuable set-up time, particularly as we want to cut down on the test drives. Curtailing the maximum engine speed is the preferred option. You don’t need peak revs for set-up work and tyre selection.” In future, the same set of tyres will have to be used both for qualifying and for the race.

By contrast, the first qualifying session, held as a flying lap between 13.00 and 14.00 hrs on Saturday, presents challenges of a very different kind. The time recorded in this single lap determines the starting order for the second timed lap (Sunday 10.00 to 11.00 hrs). Saturday’s fastest driver is the last to go out onto the track on Sunday morning.

But a good lap time on Saturday is already half the battle towards securing a good place on the grid because from that point on, the lap times of both flying laps are added up to determine the grid order. And there is a further factor
that plays an important role for final qualifying: by then the cars must have the fuel on board with which they will embark on the Grand Prix race.

Qualifying sprints and Grand Prix distances with a single engine. As Heinz Paschen, Director of Formula One Engine Development in Munich, explains: “For the engines, the new regulations mean extreme and diverse demands. They have to last the considerable duration of two Grand Prix weekends, that’s around 1,500 kilometres, and cope with qualifying sprints in between.” Developing such a flexible car is an immense technical challenge.

Paschen: “To cope with the radically increased demands for stability, in principle all mechanical and thermal components subjected to major loads had to be designed to be twice as robust as before. Normally that means an increase in engine size and weight, which in turn demands a sacrifice in engine speed and thus performance. In order to minimise these losses”, Paschen continues, “painstaking precision work is necessary all the way down the line. That starts with the design of components, is closely linked to materials research and selection, and affects production as well as testing and quality control.”

The engineers led by Heinz Paschen work in close alliance with the specialists from BMW’s Research and Innovation Centre (FIZ). The 2005 engine called for a relatively rapid response as it wasn’t until July 2004 that it was announced that the racing engine would have to be used over two consecutive Grand Prix weekends in 2005. “This late and incisive change to the specifications”, says Paschen, “led to a major supplementary development effort. By the time this regulation was made known, the engine originally planned had already reached the testing stage.”

That BMW P85 unit had to be shelved. The new project brief ran thus: on-going development based on the 2004 engine. It gave rise to the BMW P84/5. Since then, its state of design has changed by the week. Starting with the
test drives in November 2004, the team has been on the road with the latest version of the BMW P84/5 at any given time. Theissen: “Our aim is to achieve endurance for the doubled service life while minimising as far as possible any sacrifice in performance. The BMW engine is to be the benchmark for Formula One in 2005 as well.” The fact that the impact on the size and weight of the P84/5 has remained minimal is largely thanks to the materials specialists at the Research and Innovation Centre, who have developed new surface treatment processes for enhanced endurance.

The dress rehearsal, a long-distance run on the dynamic test rig, still takes place on the Monza circuit profile because of all the Grand Prix tracks it has the highest full-throttle percentage, although qualification for use has been raised to 1,500 kilometres.

Revs of yesterday and tomorrow:

“The frequently cited limit of what is technically possible does not exist”, says Theissen. “The boundary line is pushed further out with every innovation.” It’s something that is graphically demonstrated by the maximum engine speeds
of BMW’s F1 units. The P82, the engine used by the BMW WilliamsF1 Team in 2002, had hit a peak speed of 19,050 revolutions a minute in its final evolutionary stage. In 2003 the new rules stipulated that there were to be no more engine changes between qualifying and the race. With the flying lap on Saturday, the engine’s distance requirement including the race rose to around 400 kilometres and featured a complex load profile. It’s a bit like sending a marathon runner on a sprint just before the start of the long-distance event.

Notwithstanding these challenging specifications, BMW managed to achieve increases in engine speed and performance. At the season’s final in Japan, the BMW P83 managed an impressive 19,200 rpm and cleared the 900 bhp mark, while also proving a model of reliability. The only engine fault in the 2003 season was suffered at the Austrian Grand Prix and was the result of a leak
in the cooling system.

The one-weekend rule followed in 2004, signifying a doubling of the running distance. Out of 36 race starts, there was a single engine fault traceable to a faulty component. By the start of the European part of the season at Imola, BMW was again in a position to deliver a peak speed  of a good 19,000 rpm over the entire race distance – “And in seventh gear”, as Theissen emphasises, “i.e. the highest gear and the one most in use, after practically ripping through the lower gears.”

For 2005, Theissen expects a general reduction in revs. “Endurance clearly has priority. Once that goal has been achieved, we will turn to increasing engine speed and performance once again.”

Synergies between F1 and production car development:

“The Formula One project is a vast technology laboratory for BMW”, says Theissen. “For our company, the creation of synergy effects between F1 and volume production was a key prerequisite for our return to Formula One.”

And so it was clear from the start that the BMW power units for motor racing’s leading class would be developed and produced in Munich. The FIZ plays
a key role in this. The F1 factory was built less than a kilometre away from the think tank and interconnected with it. “The FIZ represents the future of BMW”, states Theissen. “Here the most capable engineers work in state-of-the-art research and development facilities. The FIZ has vast resources available from which we benefit directly. Conversely, due to the extreme technical demands and the necessary pace of development, the F1 involvement represents a unique testing ground for our engineers.”

BMW has made the vision of a seamless process chain a reality under
its own roof – from concept to construction, casting, component production,
assembly and testing all the way to deployment on the race track. That eliminates the need for transportation routes and the attendant quality risks, and the expertise acquired within the company can flow directly into the development of series production cars.

Casting technique and manufacture:

The casting quality of the engine block, cylinder head and transmission
plays a crucial role in determining the performance and endurance of the power units. Advanced casting techniques, coupled with high-precision process management, make for lightweight components with a high degree of stiffness. To ensure that production models benefit from this, BMW has its own foundry in Landshut.

In 2001, a dedicated F1 casting facility was added to it. “Both departments”, explains Theissen, “are jointly managed. That guarantees a permanent exchange.” The same sand-casting procedure as used for the Formula One V10 is applied to casting oil sumps for M models, the intake manifold for the eight-cylinder diesel engine and the prototypes for future generations of engines.

Virtually at the same time as the F1 foundry went on stream, an F1 parts manufacturing facility based on the same template was added to it. This is where the team make the camshafts and crankshafts for Formula One, among other components.

In the meantime, WilliamsF1 has also been benefiting from the two departments. The F1 aluminium gearbox casing is made in Landshut using a sand-casting process, while other transmission parts come from the BMW F1 factory. Gear wheels are produced at BMW’s Dingolfing plant in parallel with volume production.

Electronics for Grand Prix races and the road:

The demands placed on the engine management system controlling
a power unit that achieves up to 19,000 rpm, yet also has to be driveable at low speeds, are immense. Ignition timing and fuel supply have to be perfectly harmonised every millisecond in order to achieve optimal efficiency – maximum performance with minimal fuel consumption. Low consumption means better lap times as well as greater flexibility in the race strategy. Besides the engine control unit, on-board electronics are also responsible for monitoring all functions.

With the backing of the electronics experts at the FIZ, BMW has also had the confidence from the start to develop the F1 engine management system
in-house rather than depending on racing specialists. Engineers who normally deal with the electronics for the M models also created the engine management system for the F1 engines. The expertise they glean from this filters back into series production.

Top-ranging BMW cars such as the 7 Series and the M series have long featured two new types of microprocessor which BMW first used and tested in Formula One. For internet access and the navigation system of the BMW 7 Series range, moreover, storage technology was used which had first proved itself in F1. “In the area of monitoring functions too”, Theissen adds, “we are learning on behalf of road-going vehicles. Early warning systems and automated electronic interventions are important for safety on that front as well and can safeguard against damage.”

In the BMW M3, M5 and M6, a further gearbox innovation from Formula One has proved itself: the “Sequential M Gearbox – SMG with DRIVELOGIC”.
The SMG drive concept delivers F1 transmission technology for everyday use. Gear changes are electrically induced via paddles behind the steering wheel. As in Formula One, an electro-hydraulic system replaces the mechanical clutch and shift process, and SMG users can similarly keep their foot on the accelerator while changing gear.

Materials development and model construction:

As light as possible and as robust as necessary – the mantra of engine design reaches its highest plane in Formula One. Placing too much emphasis on safety means putting on weight. The materials research section of the FIZ delivers crucial initiatives for BMW’s F1 engine development, with aviation and aerospace technology frequently serving as a basis. Some highly promising developments which today cannot be considered for volume production on grounds of cost have already found their application in the BMW F1 engine. This opportunity to apply new technologies helps the engineers to continue developing them to production stage for series models.

Progress and problem solving to the relentless rhythms of Formula One are only possible with short reaction times. The number of design modifications to the Formula One engine is on a par with the entire range of production engines. New design, new tools, new components – that’s the sequence.

In order to shorten the time involved, the BMW F1 team can turn to the Rapid Prototyping/Tooling Technology department at the FIZ. As soon as the necessary parts have been designed using a CAD-CAM system, computer-guided machines use laser beams or three-dimensional pressure engineering to create scale models made of resin, plastic powder, starch or wax.

That enables installation situations and interactions to be simulated without delay so that any necessary modifications can be carried out before the final manufacturing process is set in train.

Power circuits and karting tracks.

The circuit profile of each GP course places different demands on the engines. The long straights of Monza and Indianapolis or the inclines at
Spa demand maximum power. From a Formula One viewpoint, Monaco and the Hungaroring are more akin to karting tracks. Here driveability is called
for and cooling air is at a premium. In Bahrain, fine-mesh air filters protect the engine from desert sand.


Technical specifications BMW P84/5.

Type: Normally aspirated V10
Cylinder angle: 90 degrees
Displacement: 2,998 cc
Cylinders: Four valves per cylinder
Valve drive: Pneumatic
Engine block: Aluminium
Cylinder head: Aluminium
Crankshaft: Steel
Oil system: Dry sump lubrication
Engine management: BMW

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