All Wheel Drive Adds Safety And Performance With No Mileage Penalty

Time was when all wheel drive systems increased fuel consumption by 10 to 20 percent and sometimes more. But today’s e-axles — components that use electric motors to turn the wheels instead of driveshafts and mechanical differentials — are making all wheel systems that doesn’t eat up a lot of extra gasoline more affordable.

BMW i8 features electronic all wheel drive

We always think that manufacturers makes most of the components in the cars they sell, but in fact, all car makers rely on outside suppliers for major systems. Some build dashboards, seats and interior trim. Others supply wheels, tires, and brakes. GKN is a large supply house that specializes in electronically controlled electric axles for passenger cars and SUVs. Digital controls permit the amount of power supplied by each electric motor to be precisely controlled. That can add stability to a family sedan on slippery roads or make a sports car turn in more aggressively on the track.

Electronic axles from GKN are featured in such diverse cars as the Jeep Renegade, Fiat 500X, Land Rover Evoque, Porsche 918 Spyder, BMW i8 and Volvo XC90 plug-in hybrid. The upcoming Ford Focus RS, Lincoln Continental and Cadillac XT5 will also uses electric all wheel drive systems provided by GKN. “The new systems reduce the impact AWD has on fuel economy,” GKN’s Ray Kuczera told the Detroit Free Press recently.

E-axles permit advanced torque vectoring. That’s a very popular buzz word in the automotive world these days, but there are two vastly different kinds of torque vectoring systems. One applies brake pressure to any wheel that is experiencing slippage. Kucera says such systems are wasteful, because they allow a driven wheel to receive more power than it can handle. Some of that excess power then has to be turned into heat by the brake. His company’s electronic all wheel drive system sends only the amount of power each individual wheel can handle without spinning and no more.

GKN systems are significantly lighter and less bulky than the mechanical systems they replace. They can even be programmed to shut off completely when not needed but reactivate themselves instantly when requried. That helps limit any fuel economy penalty from having all wheel drive. Robert Willig, president of GKN’s driveline business in the Americas, says “E-axles are the key to AWD growth going forward, even past the upcoming fuel economy requirements.” It’s entirely possible that the car you drive will have an electronic all wheel drive system in the very near future.

Steve Hanley

Closely following the transition from internal combustion to electricity. Whether it's cars, trucks, ships, or airplanes, sustainability is the key. Please follow me on Google + and Twitter.