Many car systems shift to electricity to boost fuel economy

David Sedgwick,Crain staff (AN)

Detroit, Michigan -- The line between hybrid vehicles and conventional gasoline-powered vehicles is blurring.

To boost fuel economy and performance, automakers are adding many features - such as power steering, stop-start engine systems and oil and water pumps - that run on electricity.

These features originally were intended for electric vehicles and hybrids, but now are being adapted to conventional gasoline-powered vehicles, too.

The goal: Improve fuel economy by minimising energy loss that occurs when vehicle accessories are powered by belt drives connected to the engine.

Gasoline-powered vehicles also are starting to get regenerative brakes, which convert thermal energy into electricity to recharge the starter battery.

Among the leaders in the effort is BMW AG, which is rolling out these and other technologies under its EfficientDynamics fuel-saving program.

BMW has introduced electric-powered oil pumps, engine coolant pumps and steering systems. Now it plans to add regenerative brakes and stop-start systems to all its vehicles, and it is developing some gee-whiz computer controls to improve their efficiency.

GM's approach

Mass-market automakers are adopting a similar approach. For example, General Motors has significantly upgraded its mild hybrid technology and reintroduced it as eAssist.

Features of eAssist, which will be available on the 2012 Buick LaCrosse and Regal and 2013 Chevrolet Malibu, include stop-start systems, and regenerative brakes that recharge a small lithium ion battery.

The lithium ion battery, in turn, provides power to the stop-start system, reducing the starter battery's workload. The separate starter battery on the three cars is a traditional 12-volt lead-acid unit.

When the vehicle accelerates, the lithium ion battery provides extra power to the wheels via a motor that doubles as the car's alternator and starter motor. A drive belt connects the alternator-starter to the crankshaft. The battery and alternator-starter alone cannot power the wheels; they only provide an assist.

To GM, eAssist is attractive because it is much cheaper than a hybrid powertrain.

"Consumers want fuel economy," says Buick spokesman Nick Richards. "But it's an economic decision, and the cost [of a full hybrid] holds them back. So we didn't redesign the entire vehicle around the powertrain."

The 2013 Malibu with eAssist gets an estimated 38 mpg on the highway, vs. 33 for the standard 2011 base Malibu.

These electrical devices have created demand for upgraded engine control units and sophisticated software to manage the electrical system.

Next big thing that wasn't

The Buick LaCrosse's regenerative brakes recharge a lithium-ion battery located in the back of the car. By contrast, BMW's system recharges the vehicle's starter battery.

But one feature that automakers are not clamoring for is a 42-volt electrical system. A few years ago, automotive engineers proposed a standardised high-voltage electrical system to handle all the electrical accessories under development.

Automakers rejected the idea because they would have to redesign vehicle electrical systems and accessories.

"It was going to be the next big thing, but it never happened," said Ford spokesman Richard Truett. "You can't use standard wires and connectors, because you don't want sparks flying around."

Indeed, the electrical accessories listed below are gaining popularity because they don't require automakers to redesign entire vehicles from scratch.

From Automotive News (A Crain publication)