"Porsche: The long wait for the crankshaft"
(7 March 2014)
Porsche had to change the firing order in the development of V4-in turbos 919 hybrid: Availability of the new crankshaft limited test operation a somewhat
About 500 hp coming from the V4-Turbo, another 250 hp from the hybrid systems
(Motor-Total) - Porsche is on the way in the new season of the World Endurance Championship (WEC). When Auto Show in Geneva, the sports car manufacturer before not only the current version of the 911 RSR for the GTE Pro class, but the star of the booth was the Porsche 919 Hybrid, with Porsche in Le Mans 17 Wants to conquer overall victory. "The idea of the car in Geneva was a special moment," says Porsche LMP1 project manager Fritz Enzinger in conversation with 'Motor-Total'.
"There were two and a half years of intensive work. First there was just the decision of Porsche, then we have two or three people in Weissach started with the simulations. Now you have the buildings, the shops, the great simulator and over 200 people in project - that's great, "says the Austrians. "We had to plan, draft, rollout and all the tests. Then if the car will be officially presented, which is obviously something very special."
With pride Enzinger looks on the finished vehicle. "This is my baby, absolutely. It has no name yet," he laughs at the sight of the 919 hybrid in the final design. The "baby" had to learn to walk. This has been possible, although it in the growth phase between rollout on 12 June 2013 and an important test in Portimao last December were problems again and again. Annoying vibrations of the new 2.0-liter V4 turbos mounted deep worry lines.
Vibrations make testing difficult at first
"You learn precisely in such situations more clearly. Was important that we recognize immediately that there are problems. We then made changes. However, the implementation of these things is defined by the delivery times of those parts that you must have changed" , Enzinger explained in retrospect. "There were parts of it that have a delivery time of 16 weeks. Was clear to us that we have to cope somehow with our existing engine in testing to the delivery of components. That was quite difficult with these vibrations."
"We had to solve these problems of vibration and a few other things. It was less pleasant to drive," Neel Jani does not mince his words. "You can already ride. It was not that us the car is immediately flown apart. However, it is difficult for us drivers. After some time, you have no feeling. Besides, it would be in a race over six or even 24 hours However, so that break or wear off the parts would. "
Great responsibility: Fritz Enzinger leads the LMP1 project of Porsche
"In the meantime it is very good. Bahrain was a great test because we did 1000 km per day. Theme vibrations is done, there is no more," added the Swiss. "The Portimao test was a very important step. Nevertheless, were the tests that we had before, never worthless," says Timo Bernhard. "When I take the stand from the rollout, then has since done so much infinite. Steps were very, very large. There were never two tests at the same level, we always had new parts."
"Crucially, as the parts were finally installed and the engine was started for the first time that the vibrations were completely gone. That was the Portimao test in December. Since each has only once breathed vigorously. That was great," says Enzinger about the breakthrough in the development of the new engine, which makes 500 horsepower - plus more than 250 hp of two hybrid systems in the 919, which drive the front axle.
New firing order: waiting for the crankshaft
"It was really true that we had to change the firing order which meant that we needed new components -. Among other things, a new crankshaft, which is the time of Delivery precisely at 16 weeks," says the head of Porsche LMP1. "Since then you have just two or three months a few possibilities. One has with life, what you have., We have taken measures to minimize the vibrations and oscillations., But it's just then only a hermaphrodite."
Although the strong vibrations of the V4 Turbos prevented a proper test run for months, so one never really presented the basic concept of the engine in question. A short-term change to a V6 turbo was never an option. "No, there was never such thoughts. We were always confident that we cope with it after the changes," said Enzinger. "The decision for the four-cylinder was already occupied by various experiments. These, we did not move away."
Porsche 919 Hybrid LMP1 and Audi R18 e-tron Quattro diesel hybrid testing at Sebring International Raceway
"I remember how we had installed the modified engine in Portimao on Friday night because everybody was curious huge Then he was let -.., And suddenly the vibrations were not only less, but they were gone," the Austrians describes the great relief in December. "Steps have since become definitely larger. Vibrations really affect the entire system greatly. During the renovation we can make normal test mode. The mileages during the tests are now highly accurate. Now it is really fun because it goes well forward."
In the center of further testing the reliability of the setup, the optimal use of the fuel and the operation of the hybrid systems are available with a total of eight rich megajoules in memory. "Let's see how to run further tests. We are this week in Sebring, then end of the month in France," says Enzinger, whose team is testing simultaneously with rival Audi in Florida. "And if we now meet in Sebring, or somewhat later in France to Audi, really makes no difference."
http://www.motorsport-total.com/wec/news/2014/03/porsche-das-lange-warten-auf-die-kurbelwelle-14030701.html