These days, it's almost impossible to write about a new car without using "ZF" somewhere in the text. It's not for our lack of proper noun skills, but for the overwhelming fact that ZF–short for Zahnradfabrik, or literally "gear factory"—has its 8HP eight-speed automatic transmission in nearly every automaker's portfolio. But ZF Friedrichshafen, on its way to becoming the second biggest parts supplier in the car industry, has more tricks up its transfer case than adding ever more forward ratios, and we explore some of them here.
For starters, ZF would like to cap the gear competition at nine. It also is planning to revolutionize rear suspensions on compact cars with a simpler, more elegant design cut from composite materials. We spoke to Bryan Johnson, ZF North America's communications director, to learn why we'll be typing the letters Z and F even more.
Car and Driver: This concept suspension—a transverse leaf spring that also locates the rear wheels – is quite different from the torsion-beam and trailing-arm suspensions favored by most manufacturers in this price point. It reminds us of the Corvette's transverse leaf spring setup. Why go this route?
Bryan Johnson: In a conventional chassis, a complex control arm and spring concept ensures optimal road holding, so the wheel-guiding transverse spring was designed to assume this task in a single component. The transverse spring assumes the control arm function as well as damping and load-carrying tasks. This component integration reduces the complexity of the axle and makes it much easier to install. In addition, fewer components mean less weight.
This is enabled by the extremely light and elastic GRP (glass reinforced plastic) which, when properly designed, can outperform the strength of high-strength steel. At the same time, the material can also be designed with very elastic characteristics—a positive aspect of its extremely flexible structure. The original design of this concept was made for a small city car that would require a smaller powertrain or electric motor.
C/D: Are you also looking into composite springs, like Audi has done?
BJ: We're investigating composite springs and shocks, lightweight aluminum shock tubes. It's coming. You have to build the vehicle around it. You can't just put it in there. It has to really be a development that's part of the new vehicle design. Every change on every property you make here has an adverse relation to something else.
C/D: At least it was easy for automakers upgrading to the new eight-speed auto.
BJ: Our eight-speed is the exact same size as our six-speed. We did that purposely so our customers could switch mid-cycle. Other than a technical application engineering of the electronics, mechanically we had very little we had to change, so driveshafts could stay the same, mounting points could stay relatively the same.
C/D: Ford just introduced the first light-duty 10-speed on the 2017 Raptor. Is ZF going up another gear?
BJ: There's potential for it, but the problem is that with every gear you add, every speed you add, you get more weight, space, and friction. So fuel economy goes down, efficiency goes down. From a ZF perspective, we think eight and nine is probably pretty sufficient. At some point, you're adding commercial gears, not efficiency gears. So, if a customer calls and wants to have a 10-speed, we'll make one. But is it the most efficient, best-performing transmission? It might not be.
C/D: Are you still on track with your expansion of the South Carolina plant?
BJ: The structure is done, we're still adding equipment. We'll be at 1.6 million transmissions total [annual capacity] by the end of 2015.
- Ratios Galore: A Deep Look at ZF's 9-speed Automatic
- ZF Jointly Developing Energy-Recovery Suspension System
- Audi's New Composite Coil Spring Shaves Weight, Enhances "Vibrational Comfort"
C/D: How much of those transmissions get exported?
BJ: All the Jaguar Land Rover stuff is exported, Chrysler is local, Honda is local. We still supply BMW in Germany. But it has to do with a lot of things. You have existing contracts, existing prices, the assembly line is already set up with existing product. It's very difficult to come up with a real logic behind some of this.
from Car and Driver Blog http://ift.tt/nSHy27
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