Lightweight Sportscars: High Performance and High MPG
Will an HCCI hybrid come to the enthusiast's rescue?
I squirm a bit in confronting the automotive enthusiast's fundamental quandary: "What are the socio-economic implications of my chosen hobby?" Or maybe it's just "Do I have enough cash in my pocket for this fill-up?"
Let's look a bit further down the road, and see how high performance and high mpg might do more than coexist in the mid- and far-term; they might well thrive. I see several interesting intertwining threads in this: light weight, aerodynamics and hybrid technology, the last featuring a variation of HCCI, homogeneous-charge compression ignition.
Weight has a direct effect on every aspect of a car's performance, its acceleration and braking, cornering, fuel consumption, even its tire wear. What's more, the payoff of lighter weight has a multiplier effect. Lighter structures breed lighter individual components. Suspension pieces, for example, can be downsized. So can engines. (Or, better yet, retain the same one for an improved lb./bhp ratio and enhanced acceleration!)
Audi and Jaguar are already showing the way with unibody structures of aluminum. Exotics like the Ferrari Enzo, Mercedes-Benz SLR McLaren and Porsche Carrera GT go a step beyond with carbon fiber. Indeed, this material also appears in the BMW M6's roof and bumper backups as well as selective substructures of the Chevrolet Corvette Z06. It's clear that my futurist enthusiast car will exploit aluminum structures as well as specialized uses of rather more expensive (and labor- and equipment-intensive) carbon fiber.
One challenge is repairability of these innovative structures. Word has it that repair costs of some current designs are encouraging insurance companies to total cars that hitherto would have been deemed repairable. It's a matter of design methodology as well as providing the auto-repair industry with new techniques.
What about safety? It seems a dictum of physics that heavier objects damage lighter ones. On the other hand, advanced design techniques indicate that size not weight is the real determinant of crashworthiness. Crush distance, controlled deformability and energy dissipation all play roles in this. My futurist enthusiast's car, lightweight though it will be, need not be intrinsically unsafe.
I'm not so confident, though, about absolutely minimalist offerings that drive through loopholes in crash testing. By contrast, major manufacturers do considerable research and development enhancing crash survivability. Honda's Advanced Compatibility Engineering is a good example. An ACE design uses high-strength steel to redistribute the loads of frontal impacts over a wider area of the car's front structure. This enhances energy dissipation and also better handles the problems of offset or angular collisions. It adds a tad of weight, but with excellent payoff in crashworthiness.