Turning the Corner

It used to be that expensive luxury cars were the first to receive the newest technology. It was true with air bags, sunroofs, antilock brakes and automatic transmissions. Today, those features are readily available — or in some cases, standard equipment — on inexpensive as well as moderately priced vehicles.

Electrically-assisted steering, however, is different. At the lower end of the market, especially in Europe, a growing number of new vehicles are coming equipped with electrically-assisted steering to reduce weight, simplify underhood packaging and improve fuel economy.

It's not on the new BMW flagship 7-series, but European buyers will find the feature on small, high-volume vehicles: the Fiat Punto and Stilo, the Renault Megane, Volkswagen Lupo and the new Mini. Japanese vehicles equipped with electrically-assisted steering include the Honda S2000 and Toyota Prius hybrid.

In North America, the 2002 Saturn Vue sport/utility vehicle will be so equipped when production begins later this year. The Ford Ranger already is available with electrically-assisted steering.

A flood of new vehicles with the technology will reach consumers in the coming years. TRW Automotive Inc., the world's No.1 steering system supplier, estimates that electrically-assisted steering, which was exceedingly hard to find two years ago, will help pilot one of every two new cars by 2010.

Delphi Automotive Systems Corp. estimates that 10% of new vehicles in North America will be so equipped by 2003.

TRW and Delphi say they have several active programs with North American automakers. In Europe, ZF Lenksysteme GmbH, already a major steering supplier, becomes even more formidable in this emerging market with its recent Robert Bosch GmbH joint venture. ZF supplies the system for the new Mini.

Other competitors hoping to capitalize on the growth include Siemens VDO Automotive, Continental AG and Japan's top steering system producer, Koyo Seiko, which supplies the system on the Vue.

Electrically-assisted steering comes in two forms — fully electric power steering (EPS) and electrically powered hydraulic steering (EPHS).

With conventional hydraulic power steering, a pump mounted to the engine provides the power necessary to turn the wheels.

With EPHS, the pump is removed from the engine, drastically reducing parasitic losses. Energy losses can be significant, as hydraulic steering draws power even when driving in a straight line. Instead, with EPHS a small motor drives the pump, and an electronic control unit drives the motor, providing power only when needed. The drive belt, pulleys and torque sensor are eliminated, and hoses become less expensive.

With EPS, the pump is eliminated entirely, as are the hoses and fluid. Instead, a computer-controlled electric motor provides the rack with all the power necessary, on demand.

On the cost side, the automaker assembles the multi-piece conventional hydraulic system. With EPS and EPHS, the OEM saves labor costs because the supplier ships a fully assembled steering system, ready for installation into the vehicle. Delphi says its system can save OEMs 3.5 minutes in vehicle assembly time.

EPHS can save 85% of the energy consumed by a normal hydraulic steering system, which translates into a 3% to 4% fuel economy improvement, or about 1.1 mpg, says Rex Struble, TRW's product business director for steering and suspension. With EPS, energy savings climb to about 90%, with an additional 0.5% improvement in fuel economy, Mr. Struble says.

The system still works if the engine stalls, making it ideal for gas-electric hybrid vehicles. “There's a strong customer pull because of that,” Mr. Struble says. The product is best suited for smaller, lighter vehicles because they require less power to turn the front wheels.

New for '02, TRW supplies EPS for the Stilo and Megane, which together represent $900 million in new business. TRW expects more than $1 billion in annual sales for electrically-assisted steering systems by 2006.

Continental's mission is not to become a supplier of complete steering systems but to integrate the electronic controls for steering with that of the brakes and suspension — the so-called “electronic chassis.”

With its acquisition earlier this year of Temic, Continental now has the electronics expertise to advance this “networking” approach to include passive safety systems as well. Air bags, for instance, can be deployed sooner if valuable information about braking or loss of vehicle control can be communicated more quickly, says Wolfgang Ziebart, who heads Continental's Automotive Systems Div.

Delphi currently produces its E-Steer electric power steering system in Cadiz, Spain (for Punto and Lupo 3L TDI), and plans to start production in early 2003 in the U.S. at its Saginaw, MI, plant. The system will be available on a “fairly high-volume” U.S. vehicle in 2004 and several more contracts in the U.S. and Europe are likely by 2005, says Larry Tomczak, Delphi's director of electrical steering systems. He says Delphi is considering another E-Steer plant in Europe.

About 80% of new Puntos sold are requested with E-Steer, he says. A popular feature is a switch that allows for stiffer feel on the highway and easier handling in the city.

At the end of this long path of steering innovation lies steer-by-wire, in which the mechanical connection is severed between the road wheels and the steering wheel. “This is a critical system, and we have to ensure that what we offer will exceed expectations,” Mr. Tomczak says. “There's still a lot of testing to get done.”

7-series Showcases Kolbenschmidt Pierburg Technology

THIONVILLE, France — BMW AG may be famous for it world-class powertrains, but the company tapped a German supplier, Kolbenschmidt Pierburg AG, for its considerable component and engineering expertise in developing two new gasoline engines for the all-new for '02 7-series flagship.

BMW's 3.6L and 4.4L V-8s will feature two KP components never before used on production vehicles: a continuously variable air intake manifold and a two-stage variable oil pump. Also for the 7-series engines, KP will supply the aluminum engine blocks, secondary air system (for reduced emissions), aluminum pistons, exhaust flap (for noise reduction), bearings and electric fuel pump. KP executives discussed the BMW business with American journalists visiting KP's plant here before the start of the Frankfurt Motor Show.

KP was first to market several years ago with an “active” air intake manifold for Audi AG. More recently, KP supplied Audi with a V-8 manifold equipped with two flaps that open and close depending on driving conditions. By varying the lengths of the intake runners, the three-stage manifold provides more responsive air flow and makes for a more optimized torque curve.

With the 7-series, KP has a patented new technology that allows the length of the intake runners to be infinitely variable. Based on engine speed, the inner manifold turns on a shaft so that the length of the scroll-shaped intake runners is constantly changing, says Wolfgang Reuter, managing director of the Pierburg air supply and pump business.

The principle is simple: the shorter the runner length, the higher the torque. The engine controller governs the system and tells it what runner length is necessary. An electric motor turns the shaft, but the system runs only when engine speed changes. The system is intended for gasoline engines.

KP began producing the new manifold two months ago at its plant in Nettetal, Germany.

KP offered its two-stage variable oil pump to BMW to eliminate energy losses normally associated with mechanical oil pumps, which normally run off the crankshaft whenever the engine is operating.

The new oil pump is equipped with two rotor sets, controlled by a hydraulic actuator, that switch on and off based on driving conditions. When an engine is started, for instance, both rotor sets are running, pumping maximum oil through the engine, Mr. Reuter says.

During normal driving, one rotor set idles because the other can pump sufficient oil through the engine. At high-rpm, even less oil pumping is needed, so one rotor set idles and the other partially idles.
— Tom Murphy