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Ingram: Porsche Pushes Hybrid Envelope

Jonathan Ingram | Senior Writer, RacinToday.com Monday, May 17 2010

The Porsche 911 hybrid skips across a rumble strip at Nurburgring over the weekend. Green does not mean slow. (Photo courtesy of Porsche North America)

By Jonathan Ingram | Senior Writer
RacinToday.com

From the Monday Morning Crew Chief:

Nurburgring, Germany –  You’ll have to excuse Hartmut Kristen, the director of Porsche’s motorsports program. If you start talking about green racing, he shrugs with his eyes and doesn’t quite conceal his disdain. Green racing may no longer be oxymoronic, but it’s also a phrase that’s easy to tap into by sloganeering or a mere switch to new fuel blends.

“Our car is orange because that is the color of the material that covers the cable for our hybrid system,” he says of the new Porsche GT3 R Hybrid. “It’s not green!”

Having committed to the idea of environmentally better performance and efficiency, Porsche unabashedly showed the colors of the Hybrid at the annual 24-hour race at the Nurburgring on Sunday against a field deeply endowed with rival production car manufacturers as well as the private entries that show up by the dozens. When the race took the green flag, 198 cars roared off into Turn One of the Grand Prix circuit before switching over to the long journey on the legendary Nordschleife, where one lap comprises 14 miles.

It ended in tears and smiles for the lads from Weissach. Their car blew its combustion engine while leading at the 22-hour mark. Having led from the wee hours versus the factory Audi R8’s, BMW M3’s and a surprising Ferrari 430 GTC from Hankook Team Farnbacher, there was deep disappointment in the Porsche garage – for about an hour.

Then it sunk in. Their new baby had proven the efficacy of hybrid racing with technology that can be transferred to production vehicles. “Next year, I’m going to build an electric engine for the rear axles!’ joked one of the Porsche engineers for the car with traditional motive power in the back and electric motors/generators on the front axles.

I was invited by Porsche to the Nurburgring to get a close-up look at the Hybrid, which is a traditional production-based 911 GT3 R with some unique technology installed between the front wheels and on the floorpan where a passenger might ordinarily sit. The electric motors that alternately works as a generator span almost the full length between the front wheels. They are connected to a “hybrid box” which captures the charge in the front trunk of the 911. The box is connected by those orange cables to the floor-mounted flywheel sitting next to the driver.

Working as generators under braking, the electric motors supply enough drag to help slow the car down. After the maximum electrical charge has been produced and transfered to the “hybrid box,”  then stored in the composite flywheel, the electric generators are disengaged and the braking system returns to full use of the mechanical stopping method of discs and calipers. The driver then discharges the energy stored in the flywheel, which sustains enough RPM to provide a charge for six to eight seconds, by pulling a small paddle on the steering wheel

The Williams Grand Prix Engineering-built flywheel revs up from 28,000 RPM to 40,000 when fully charged. When the system is directed to work in reverse as the driver pulls the paddle on the steering wheel with his fingers, the energy sustained by the flywheel is converted back to an electrical charge and sent back through the “hybrid box” in the front trunk through those orange cables, then transferred to the electric motors between the front wheels. The result is roughly 120 kilowatts of power instantly applied through the two front wheels. Combined with the 480 horsepower already available from the flat-six Porsche engine in the rear, the car briefly becomes a formidable all-wheel drive machine.

Driver Richard Leitz estimated that he used the electric motors 25 times per lap in the race. “We didn’t wait until it was fully charged sometimes,” he said. “We used it for more power going up the hills and for overtaking other cars. Also, we could short shift while using it to get better mileage.”

This is a complicated system that delivers performance benefits that are adjustable according to both how the car is set up and how the driver elects to use the instant torque and power of a charged flywheel. The net effect was a heavier car at the 14-mile Nurburgring that went 10 laps on one tank of 120 liters of fuel versus competitors who managed either eight or nine.

One downside to the equation is the extra weight of those electrical engines up front – although Leitz said it helped to balance the sometimes tail-happy, rear-engined Porsches.

“The weight balance we get in the front was really good,” he said. Also, the electric motors in generator mode produce resistance if they are used on straightaways to generate power by briefly engaging them via a push of the “Rekup” button on the dash.

The system’s complication is another downside. None of the engineers at Porsche thought either the weight or the resistance of the electric motors when engaged on the straights as generators caused any problem for the engine. But one of their normally bullet-proof flat-sixes had a rare internal failure.

There are some big, long challenging hills through the forest at the Nurburgring, which invariably lives up to its legendary status. Led by Kristen, Porsche’s biggest uphill battle with the GT3 R Hybrid will be getting rule makers outside of Germany – i.e. at Le Mans – to shift the focus in endurance racing to fuel efficiency to stay relevant.

Kristen is in favor of a system that measures the energy in different forms of fuel – gas, isobutanol, ethanol, diesel or hydrogen, for example – and limits everyone to the same amount of energy from these fuel sources. “What is the message you are trying to give to the public?” he said. “You need to focus on the total amount of energy and the flow of energy (in the pits),” he said. In other words, inefficiency would leave people behind in performance.

At the Nurburgring, Porsche’s hybrid trailed one of the powerful Audi R8 LMS after the first 11 hours. But the Audi departed with mechanical failure deep in the night when the fires leap higher and higher at the multitude of hillside campsites in an otherwise dark forest. With three hours remaining, repairs had to be made to an exhaust header on the leading Porsche (another unusual event for its combustion engine). But the hybrid led from the factory BMW M3 GT2 by four minutes and 25 seconds once back out of the garage. The BMW drivers, the eventual winners, were able to match the lap times of the GT3 R Hybrid, but trailed because their V-8 had needed more frequent pit stops.

The race suggested performance as well as efficiency can be part of the equation with hybrids in endurance racing – as the story unfolded in Formula One last year when the teams of McLaren and Ferrari won races in the latter half of the year under power from Kinetic Energy Reovery Systems.

Just as he shrugs off the green debate in favor of a strong technical commitment, Kristen shrugs off the possibility of sports car races becoming efficiency runs without enough competition to hold fans’ attention. His company, of course, envisions a future building street cars with over 400 horsepower that can also switch to electric-only mode for driving in inner cities where combustion engines have been banned.

It remains to be seen how much of the future of racing involves producing performance and effiency, whichever way you color it. At the Nurburgring, Porsche declared which direction it is headed.

Quote of the Week: American Leh Keen finished second at the Nurburgring in the Hancook Team Farnbacher Ferrari, but not without incident in the heavy traffic.  “When you get up behind somebody at night they can’t see (because of the trailing headlights),” he said. “The slow cars are incredibly slow, some of them 80 miles an hour slower. It’s so dangerous. The worst part was when it went from night to day when the fog was coming in. The track started getting slippery and everybody was flying off left and right. I was just being a little more careful. But I was already alongside a BMW and he just whacked the car. It was a huge hit. We were over 100 miles an hour fender to door. I was on the right side so I was set up for the next righthand corner and I didn’t go off. But it left a big doughnut on the door.”

See ya…at the races!

– Jonathan Ingram can be reached at jingram@racintoday.com

Jonathan Ingram | Senior Writer, RacinToday.com Monday, May 17 2010
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