FIA电动方程式赛车第二赛季于2015年10月17日在中国北京启动，奥迪跑车团队的独家技术伙伴ABT舍弗勒已准备好展示其全新的全电动传动系统。

“为了决定是使用1台电机还是2台电机，以及使用几速的变速箱，我们进行了大量计算。最后我们决定，使用1个电机、1个三速变速箱、以及符合法规要求的中央差速器，以实现最佳性能，”舍弗勒执行CEO兼首席技术官Peter Gutzmer教授表示。“”

Gutzmer以及其他参与开发世界首个全电动车赛道的人员，在第二场季前赛的测试期间接受了《汽车工程杂志（Automotive Engineering）》的采访。季前赛将在位于英格兰多宁顿堡的著名景点——多宁顿公园赛道举行。

在2014-15年的首次赛季中，无论在欧洲、亚洲还是美洲的赛道上，参赛的40辆碳纤维/铝制单体壳底盘单座赛车全部搭载了麦克拉伦的传动系统。在2015-16赛季中，尽管所有电动方程式赛车依然使用威廉姆斯先进工程公司的28 kW·h储能电池，但是每个团队都可以自行选择传动系统。

FIA电动方程式锦标赛通讯专家Andrew Van De Burgt表示，10个车队中有8个不愿继续使用第一赛季的传动系统，该系统使用的是 Hewland Engineering的五速换档拨片序列式齿轮箱。这8个团队选择与技术专家合作，以开发一款全新的传动系统。

“目前参赛的变速箱从一速到五速都有。在去年比赛的启动环节中，个个参赛队成绩水平比较类似，因为大家使用的是同样的变速箱。而今年变速箱各不相同，因此我们可以看到截然不同的启动风格，” Van De Burgt表示。

从噪音角度看，由于变速箱和电机发生了变化，因此声音也会不一样。“你可以瞬间听出哪一辆是ABT/舍弗勒的车，因为它比其他车响得多。你也可以听出马恒达队、龙之队和文图里队的车，因为它们非常安静。因此，今年的赛车听起来会很不一样，”Van De Burgt表示。

ABT舍弗勒的奥迪团队希望通过更换传动系统，继续保持上一赛季的冠军成绩（共9个奖位），该系统使用的是一台纯电动电机，能够提供比去年更高的效率和扭矩。

Gutzmer表示，舍弗勒电机比2014-15赛季中使用的麦克拉伦电机轻了57-lb (26-kg) ，后者加速至62 mph (100 km/h)需要3秒。“重量真的轻了很多。整个系统都是新的。但包括转子在内的部件都已经其他商用车和赛车中使用过，”Gutzmer表示。

这台三速手动变速箱是由Hewland按照舍弗勒的要求生产的，比去年的更坚硬、更紧凑。“我们将注意力全都放在效率提升和实现最大扭矩上，这台三速变速箱在这两方面上都比上一季的五速变速箱更出色，”Gutzmer表示。“我们认为，这台三速变速箱将是整个传动系统的制胜法宝。”

舍弗勒传动系统的另一大研究重心在于热效率的提升。

“如果你将电池的一部分能量仅仅用在克服导线、电机和其他地方的电阻上，那么这将造成巨大的浪费，因为你在驾驶的时候不能使用这些能量。我们将传动系统的热效率提高了3%，而且在某些驾驶情况下还能达到8%。这是一个很大的进步，因为这让电池的使用变得更为合理，”Gutzmer强调。

ABT舍弗勒奥迪团队的赛手Lucas di Grassi表示，能源管理至关重要。上一赛季中，比赛认证用的锂电池功率限定在为200 kW以内，比赛时最高可达150 kW，最大可用能量为28 kW·h。

“今年赛季的认证功率没有变化，但比赛时的功率限值改成了170 kW，比上一赛季高了20 kW，最大储能则保持不变。因此，除了提高电机功率之外，还得提高它的效率，因为加速时消耗的能量将会更多，”di Grassi表示。

Gutzmer说，来自舍弗勒、ABT和奥迪车队的技术专家都参与了软件程序的重新编写，“这样做不仅可以彻底改变车辆的行为，而且还能对变速箱和电机进行调谐。”

Di Grassi的队友Daniel Abt表示，赛车的后悬架也进行了相应修改。“因为首先改变的是电机和变速箱，所以悬架上的连接点也必须更改。我们更换了弹簧、缓冲器，所以后悬架也是全新的。”

赛手Daniel Abt 的比赛工程师Jacky Eeckelaert称，这些修改共同造就了一辆性能更出色的赛车。Eeckelaert 在2014-15赛季中担任di Grassi 的比赛工程师，他表示，“如果将今年和去年的数据进行比较，可以清楚地看到，新车的传动系统不仅更出色，而且底盘及整体的动力学性能也更好。”

Van De Burgt称，尽管车队不能在2015-16赛季开始前透露这台全电动传动系统的深入技术细节，但随着比赛的进展，将会披露更多信息。“让人们相信，电动方程式锦标赛中使用的技术将会在未来的公路车辆上应用，这种带有推广效应的展示，对我们来说非常重要。”

在电动方程式锦标赛中登场的各种传动系统解决方案，展示了未来电动汽车的无限可能，车队主管Hans-Jurgen Abt表示。“最好的技术通常都来自于赛车。在第二赛季中，舍弗勒等赛车制造商将展示出他们的最大能耐。”

作者：Kami Buchholz

来源：SAE《汽车工程杂志》

翻译：SAE 上海办公室

Schaeffler's electric powertrain primed for FIA Formula E racing

The second season of FIA Formula E begins in Beijing, China on October 17, 2015, with the ABT Schaeffler Audi Sport team’s exclusive technology partner ready to demonstrate its novel all-electric powertrain.

“We did a lot of calculations because we needed to decide on one or two electric motors and the number of transmission gears. A single electric motor and a three-speed transmission in combination with the [rules-required] central differential is what we determined would be the best package for achieving optimal results,” said Prof. Dr.-Ing Peter Gutzmer, Deputy CEO and Chief Technology Officer forSchaeffler AG.

Gutzmer and others involved in the world’s first all-electric racing circuit spoke withAutomotive Engineering during preseason two testing at the renowned Donington Park Racing Circuit in Castle Donington, England.

In the 2014/2015 inaugural season, all 40 carbon-fiber/aluminum monocoque chassis single-seat cars ran a standardized McLaren Applied Technologies powertrain on street courses in Europe, Asia, and the Americas. Although each Formula E racecar still uses a Williams Advanced Engineering-supplied battery with 28 kW·h of stored energy, each team could elect to run a unique powertrain in the 2015/2016 season.

Andrew Van De Burgt, FIA Formula E communications specialist, said eight of the 10 race teams chose not to stay with the season-one powertrain package that featured a Hewland Engineering five-speed paddle shift sequential gearbox. The eight teams opting to develop and homologate a new powertrain did so via partnering with technology specialists.

“We literally have everything from a single-speed to a five-speed transmission. Last year, the [race] starts were pretty uniform because everyone had the same transmission. Now with this vast difference in transmission technology, we could see a really big difference in the way they start,” Van De Burgt said.

From a noise perspective, there’s been a sonic sound shift from the first season because of the transmission and motor changes. “You can instantly tell the Abt/Schaeffler car because it’s much louder than the other cars. And you can tell the Mahindra, Dragon, and Venturi [team] cars because they’re really quiet. So there’s an audible difference this year,” said Van De Burgt.

The ABT Schaeffler Audi Sport team hopes to top last season’s nine podium finishes with the switch to a new powertrain that spotlights an electric motor that is more efficient and provides more torque than the predecessor.

Schaeffler’s electric motor drops double-digits in weight compared to the 57-lb (26-kg) McLaren Electronic Systems-supplied motor that propelled a 2014/2015 season racecar from 0 to 62 mph (100 km/h) in 3 seconds, according to Gutzmer. “It is a really significant weight savings. The whole system is new. But the components that we are using, including the rotor, have been approved already in other applications, [namely] commercial vehicles and motorsports,” said Gutzmer.

The three-speed transmission is being produced by Hewland to Schaeffler specifications. This new manual transmission is stiffer and more compact. “We were really focused on efficiency and maximum torque, and the three-speed transmission allows much more than last season’s five-speed transmission,” said Gutzmer. “We think the three-speed transmission is a success factor for this powertrain.”

Another focal point of the Schaeffler-developed powertrain was thermal efficiency.

“If you are taking energy out of the battery and using it just for resistance in the wirings, in the motor, and in other areas, that means a loss of power in terms of what you’re unable to use while driving the car. We improved the powertrain’s thermal efficiency in the 3% range, and it could be up to 8% better in certain driving situations. That’s a big step because it’s really important to be smart about battery usage,” Gutzmer emphasized.

Team ABT Schaeffler Audi Sport driver Lucas di Grassi said power management is vital. Last season each driver had 200 kW of power for qualifying and 150 kW of maximum power during a race from the Li-ion battery with maximum usable energy of 28 kW·h.

“The energy for qualifying remains the same, but we’re now allowed to use 170 kW in the race, so that’s a 20-kW increase over last season from the same amount of energy. So basically apart from making a motor that delivers more power, it has to be more efficient because when you accelerate, you’re using more energy,” said di Grassi.

Technical specialists from Schaeffler, ABT, and Audi Sport were involved in rewriting software code, according to Gutzmer. “It was done to alter the complete driving behavior of the car, and also was done to address the tuning of the transmission and the electric motor,” Gutzmer said.

Di Grassi’s teammate said a revised rear suspension rounds out the racecar alterations. “It starts with having a different motor and gearbox, so the connection points from the suspension change. We have different springs, different dampers, so the rear-end is all-new components,” said Daniel Abt.

All the modifications equal a better racecar, according to Jacky Eeckelaert, race engineer for driver Daniel Abt. “When we compare the data from this year to the data from last year, it’s clear the car is more competitive in terms of the powertrain and also in terms of the chassis/vehicle dynamics,” said Eeckelaert, who was the race engineer for di Grassi in the 2014/2015 season.

According to Van De Burgt, even though teams are hesitant to divulge in-depth technical details in advance of 2015/2016 racing, more information on the different all-electric powertrains is likely to be revealed as the second season progresses. “It’s very, very important for us to show a trickle-down effect from the technology that’s being used in Formula E to the technology that’s going to be used on the road cars of the future,” said Van De Burgt.

The various powertrain solutions featured in Formula E shine a bright light on what’s possible with future electrified vehicles, according to team owner Hans-Jurgen Abt. “All the good things come from motorsports normally. And now in season two it starts with Formula E and the participating manufacturers, like Schaeffler, who want to show the potential of what they can do.”

Author: Kami Buchholz

Source: SAE Automotive Engineering Magazine