高端汽车制造商的顶级车型正在遭遇大滑坡，因此在推出新车的时候，各大制造商都想方设法赋予车辆更奢华的配置和更尖端的科技。

在2015年法兰克福车展上，宝马揭开了全新7系的面纱，直接对战梅赛德斯奔驰S级与奥迪A8等车型。尽管使用在跑车上的碳纤维材料还未在轿车中普及使用，但2016年的宝马7系向人们展示了这一方向，7系的底盘使用了强化碳纤维制作，坚固程度堪比钢结构。宝马将这一混合材料称为“碳内核”。

车门、行李厢盖、悬架、制动和车轮部件都是用铝合金制作，为车身结构减轻了15%的重量。

“这种将碳纤维结构与钢材、铝材、镁和塑料相结合的做法使750i xDrive比旧版车型轻了130 kg (287 磅)，”宝马研发委员会成员Klaus Frolich指出。“轻量化设计总共实现了200 kg (440 磅)的减重，这样我们可以为车辆添加更多的舒适与安全配置。这让7系成为了该级别中最轻的豪华轿车。”

从外部来看，7系新添的一系列主动设计使车身外壳的形状与空气流动更为流畅。其中包括格栅百叶窗和前翼子板上的垂直进气口。前者的作用相当于一块“空气挡幕”，可将气流导向轮罩拱的外侧，而后者则是一个“呼吸器”，可将空气直接吸入前轮罩拱。这些主动设计加上密封的车身底座一共可减少15%的气动阻力。

7系的前方与后方都安装了自调平空气悬架。在上陡坡的时候，驾驶员可以手动将车辆抬升20 mm (0.8 英寸)，而在高速行驶时，车辆会自动降低10 mm (0.4 英寸)以减小阻力。

主动防倾杆是一个在SUV上越来越常见的装置，它的作用是车辆转弯时先松开车轮，再减少车身倾斜。新7系上使用的防倾杆可在车辆直线行驶时，让每个角落的悬架对路面磕碰实现独立反应，不会互相干涉。只有在转弯时，防倾杆才会发挥它的本来作用——减少车身倾斜。

此外，7系还有一个可变速率转向架和主动后转向系统，它们也为操纵性能的提升做出了贡献。

其他技术呢？比如远程控制自动泊车技术？“这一技术可以让汽车自动进出车库或停车场，而驾驶员无需用方向盘操纵” ，Frolich解释道。驾驶员则使用宝马新推出的“显示钥匙”（Display Key），它的外观是一个小型的智能手机。驾驶员可以用它来启动车辆，查看锁门状态和服务通知等信息。新7系将于今年秋天登陆经销商，届时还不会带有远程控制泊车系统。但他补充道，这一技术不用等多久便会推出。

Frolich自信地邀请客户试用7系上全新推出的姿势控制系统。这是车载信息娱乐系统中的一个界面，可读取该方向上的驾驶员的各种姿势，并判断驾驶员是否试图控制某个功能，如听收音机和使用电话等。考虑到宝马语音控制系统和iDrive界面在过去的市场反应褒贬不一，这个新的姿势识别电脑系统性能如何，还需进一步观察。

宝马对其标志性的iDrive信息娱乐系统界面进行了进一步升级。10年来，宝马一直坚称指纹会弄脏触屏，但今年它终于在控制旋钮之外加上了触屏输入。

具有1个10频道、1400 W扩音器与16个扬声器的Bowers & Wilkins钻石环绕式音响系统，可让车内乘客充分沉浸在音乐中。此外，7系还采用了一个全新的平视显示仪。该设备可将信息以图像的方式投射在挡风玻璃上，投射画面比旧系统大75%，图像质量与呈现细节也更加完善。

宝马公布了美国市场上7系的三种传动系统：750i将使用一台445马力(332-kW)的双涡轮4.4 L V8发动机，740i将使用一台320马力(239-kW) 的3.0 L双涡轮直列式6缸发动机，而740e将采用由一台258马力(192-kW)2.0 L双涡轮直列式4缸发动机与83 kW电机组成的插电式混合动力系统。混动系统的总输出功率为243 kW。三辆车都搭载了八速自动变速箱。

V8发动机采用“热V”设计，意味着一对霍尼韦尔双涡轮增压器位于V字中间。新一代发动机的压缩率为10.5:1，比旧款高了0.5。冷却系统也得到了优化，一个由地图控制的水泵让水流朝着气缸盖和气缸组两个方向流动。冷启动时，系统流量被限制在正常水平的10%，这样可使机身更快地升温。

直列式6缸发动机为全铝材结构，具备可变阀门正时和汽油直接喷射等功能，运行顺畅且功率强大。

插电式混合动力版740e的锂离子电池组可在不使用燃油的情况下确保75 mph (120 km/h)的驾驶速度，纯电动行驶里程高达23英里(37 km)。可采用的充电方式包括标准家用电源、公共充电桩，和宝马的i Wallbox。宝马声称该车的最大效率为112 mpg。

此外，宝马还将在全球市场推出730d，它将搭载一台265马力(198-kW)、52 mpg的3.0 L直列式6缸柴油发动机。

作者：Dan Carney

来源：SAE《汽车工程杂志》

翻译：SAE 上海办公室

BMW lightens 7 Series, but bulks up on tech

Prestige car manufacturers are trading body blows among their top-segment models, with each ladling on more lavish content and more cutting-edge technology with each new introduction.

So it was for BMW at the 2015 Frankfurt Motor Show, where it pulled the cover off its 7 Series and released it to take on the Mercedes-Benz S-Class and Audi A8. We may not have yet reached the day when carbon-fiber chassis seen in sports cars have proliferated among these sedans, but the 2016 7 Series offers a step in that direction with a chassis featuring significant carbon-fiber reinforcement to a mostly steel structure. BMW terms this hybrid materials approach “carbon core.”

The car’s doors and trunk lid are aluminum, and use of that metal in the suspension, brakes, and wheels slashes unsprung weight by 15%.

“Its innovative combination of carbon-fiber structures with steel, aluminum, magnesium, and plastic means that the 750i xDrive is 130 kg (287 lb) lighter than the previous model,” noted Klaus Frolich, BMW Board Member for Research and Development. “Lightweight design measures adding up to roughly 200 kg (440 lb) have enabled us to integrate additional comfort and safety features,” he said. “This ensures that the 7 Series is the lightest luxury sedan in its segment.”

Outside, the body shell is smoothed and airflowed aided by active measures such as grille shutters, an “air curtain” that steers airflow past the side of the wheel arch, while “air breathers” direct air into the front wheel arches through vertical intakes in the front fenders. These measures, along with a sealed underbody, contribute to a 15% reduction in aerodynamic drag.

Front and rear self-leveling air suspension lets drivers manually raise the car by 20 mm (0.8 in) when approaching steep entrances and automatically lowers is by 10 mm (0.4 in) when driving at highway speeds for reduced drag.

An active anti-roll bar is a feature increasingly seen on SUVs because it permits disconnection for wheel articulation when driving off road, then returns to its normal function of reducing body lean in turns on road. The new 7 Series uses one so it can disconnect the bar when the car is driving in a straight line to let each corner’s suspension respond to bumps individually, without affecting the others. When turning, the anti-roll bar returns to its normal function.

The 7 Series also has a variable ratio steering rack and active rear steering, which combine to provide improved maneuverability.

What else? How about remote control self-parking? “This means the vehicle can maneuver itself in and out of a garage or parking spot without the driver behind the wheel,” Frolich explained. The driver will use BMW’s new Display Key, which appears to combine the appearance of a small smartphone with functions such as starting, the car’s lock status, and even service notifications. Remote-control parking will not be available when cars reach dealers this fall, but is scheduled to follow soon afterward, he added.

Frolich boldly invited customers to try the 7 Series’ new gesture-control system, an interface for the car’s infotainment systems that reads the driver’s gesticulating in its direction and interprets that to control functions like radio and phone. Considering the mixed record of voice command systems and BMW’s iDrive interface, it is worrisome to consider what gestures the computer system might induce.

BMW continues to refine its signature iDrive infotainment interface, finally combining touch screen inputs with its control knob despite a decade of insisting that fingerprints make touch screens undesirable.

A Bowers & Wilkins Diamond surround sound system features a 10-channel, 1400-W amplifier and 16 speakers to immerse occupants in sound. Meanwhile a new headup display projects information for the driver with an image on the windshield that is 75% larger than the previous system, with improved image quality and detail.

BMW has announced three U.S. gasoline drivetrains for the 7 Series; a 445-hp (332-kW) twin-turbo 4.4-L V8 for the 750i, a 320-hp (239-kW) 3.0-L twin-turbo inline six for the 740i, and a 258-hp (192-kW) 2.0-L twin-turbo inline four and 83 kW electric motor plug-in hybrid-electric combination in the 740e. The hybrid's total system output is 243 kW. All three cars use eight-speed automatic transmission.

The V8 is a hot-vee design, nesting a pair of Honeywell twin scroll turbos in the valley of its vee. Compression for this iteration of the engine climbs a half-point to 10.5:1, with cooling optimized with separate flow to the heads and cylinder liners determined by a map-controlled water pump. System flow can be restricted to 10% of normal for faster warmup on cold starts.

BMW is debuting a new inline-six for 2016 featuring all-aluminum construction, variable valve timing, and direct gasoline fuel injection for a good combination of smoothness and power.

The plug-in hybrid 740e has a lithium-ion battery pack that can propel the car with no fuel consumption at speeds as high as 75 mph (120 km/h) or for distances as far as 23 mi (37 km). Charging is via standard household current, public charging station or BMW’s i Wallbox. BMW claims maximum efficiency of 112 mpg for the plug-in hybrid

Global markets will also enjoy the 730d, a 265-hp (198-kW) 3.0-L, 52-mpg fuel-sipping 3.0-L inline six-cylinder diesel.