BMW has been offering some intriguing glimpses of its future direction in a wide range of new product announcements over the past couple of weeks. But a common theme can be found in all of them.
BMW is building cars with smaller engines that provide adequate power which they then supplement that with additional ‘power adders’, turbos, Vision EfficientDynamics multiple source power train. (In a more pedestrian vein, that’s what Chevy is doing with the Volt.), and now mention of an F1 type Kinetic Energy Recovery System (KERS) in the next M5.
But, regardless of engine size, for BMW performance comes first. Think of this mantra, maximize performance when requested, minimize consumption when not.
With the direct injected turbo six cylinder and V8 models (as well as turbo three, four, and six cylinder diesels), BMW has managed to retain step up power levels in step down fuel consumption levels. Now they will move onto moving smaller engines in bigger platforms and supplement them with electrical energy. That was the vision of the Vision EfficientDynamics. And now the next M5 may lead the way with the integration of that vision into production M vehicles.
The new M5 receives a version of KERS utilizing super capacitors. The super capacitor is an electric double-layer capacitor which can have energy densities thousands of times greater than normal capacitors. Super capacitors can also be recharged quickly, transferring what otherwise would be heat energy in the braking process to stored electrical energy. The notion is that they can store quite a bit of energy, but it is released in a brief surge which can then be ‘refilled’ quickly.
The KERS functionality will be implemented in the transmission most likely. BMW partnered with several other manufacturers to implement hybrid capabilities in a transmission over the past several years. The ZF eight speed automatic used in the 5er Gt and new 5er can be mated to a torque convertor or an electronic wet clutch so there is some possibility that this will be the core of the 8-speed DCT used on the M5.
Another technology mentioned to be utilized in BMWs is ‘press hardening’. Currently most stamping operations occur with cold blanks pressed in dies. Press hardening takes pre-heated blanks, presses them while hot in a controlled atmosphere and then cools them. It changes the micro-structure of the material, enhancing the strength of the material being pressed. This allows you to use less material for equal strength, or by using the same amount of material, to significantly increase strength. BMW seems to build ’space frame’ vehicles with a large percent of the exterior skin hung, unstressed, on the unibody. Enhancing the strength of the unibody and reducing the weight of the cosmetic panels is appealing (annealing? ; -).
So, the goal is light weight, strengthened materials, reduced power consumption from internal systems (alternator, a/c, steering and eventually brakes), maximize reuse of what would be heat energy (regenerative brakes, the KERS, and scavenging heat from the exhaust using a thermal reactor as in the Vision EffecientDynamics), then supplement the base power train with enough energy to provide BMW like acceleration.
It’s a brave new world!
Author: Hugo Becker
Source: http://www.bmwblog.com/2009/12/21/bmws-brave-new-world/