Ford Ecostars on the Highway

Today, we take the advanced batteries that power electric vehicles for granted. Lithium-ion batteries, which followed advanced lead-acid and nickel-metal hydride, is mainstream. Many exotic EV battery technologies were tried over the years, including the sodium-sulfur battery in Ford’s Ecostar.

Early electric vehicle efforts took many forms, with automakers striving to compress the learning curve in order to meet California’s impending 1998 zero emission vehicle mandate. While a few automakers like Honda developed their electric vehicle programs around all-new designs, most turned to electrifying existing car, truck, minivan, or SUV platforms. Some were recognizable models sold in the U.S. Others, like Ford’s Ecostar, were built on platforms sold only abroad. The Ecostar was unique in many respects, not the least of which was its use of an experimental sodium-sulfur “hot” battery, which provided exceptional on-board energy. Ultimately, this battery didn’t make the cut and was abandoned, although the Ecostar itself still shines as one of the era’s true stars. This article shares details of Ford’s Ecostar program and is presented as it originally ran in Green Car Journal’s December 1993 issue.

Excerpted from December 1993 Issue: It was just over a year ago when Ford debuted its Ecostar electric vehicle to the skeptical motoring press in Los Angeles, Calif. The unusual vehicle, based on the automaker’s European Escort Van built in Britain at Ford’s Halewood, Merseyside, manufacturing facility, seemed normal enough at first blush. But its powertrain made it the most unique vehicle ever to hit Hollywood’s Sunset Strip.

Green Car Journal editors who drove the Ecostar found it to be an extremely capable EV, perhaps the best to date. But there were a few small glitches including an occasional drivetrain shudder and a degree of inverter noise. A recent test drive in a more refined Ecostar example illustrates just how far Ford has come in its electric vehicle project. The only two glitches we had noted were conspicuously gone, and the Ecostar drove better than ever.

“The shudder was an interaction between the drive system and the mechanical system it was driving, creating a resonance,” Ford’s Bob Kiessel told Green Car Journal. “What we had to do was compensate for that resonance. It’s all done electronically.” Evolutionary changes in the controller also eliminated the high-pitched noise noted on the earlier drive. The Ecostar’s gauges and diagnostics were also working this time around, a simple matter of more time spent dialing in the EV’s many functions and subsystems.

During this most recent drive, we were aware of a significant amount of tire noise making its way to the cabin. Because this also created its own unique resonance, it was cited by some drivers as motor noise, a suggestion that Kiessel denies. Even so, he offers that improvements are in the works.

“We’re testing a next-generation motor-transaxle that cuts the noise level down by an order of magnitude,” Kiessel shares. Tire noise will be engineered out, at least to a greater degree, as R&D work on the Ecostar continues.

There was a reason for the Ecostar’s recent coming out party. Ford has completed a number of the Ecostar examples it began assembling in June and was preparing to deliver them to fleets for real world testing over a 30-month period. Fleets taking delivery: Southern California Edison (Los Angeles, Calif.); Pacific Gas & Electric (San Francisco, Calif.); Allegheny Power (Frederick, Md.); Commonwealth Edison (Chicago, Ill.); Detroit Edison (Detroit, Mich.); and the U.S. Dept. of Energy (Washington, D.C.).

Ecostars now being driven on U.S. highways are milestone vehicles in that they’re the first to travel under power of advanced batteries. The 37 kWh, 780-pound sodium-sulfur battery, built by ABB (Heidelberg, Germany) for Ford, allows the 3100-pound Ecostar to achieve a conservative Federal Urban Driving Schedule range of 100 miles. Acceleration on the highway is brisk enough to meet daily driving needs. Ford estimates 0-60 mph acceleration at about 16.5 seconds, in the realm of a Volkswagen EuroVan powered by a 2.5-liter inline 5-cylinder engine. Top speed is cited as 75 mph.

Once the entire 105 vehicle fleet is fielded in the U.S., Mexico, and Europe, it’s expected that Ford will get plenty of feedback on how these vehicles perform and how they can be fine-tuned for the real market.

“This vehicle is a learning tool for us in several different ways,” says Kiessel, “from a design standpoint to an engineering skills standpoint, and from a supplier development standpoint to market development and service. It’s a probe to learn. What we’re trying to do is focus on the things that will help us make better electric vehicles in the future.”