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The ESX3: getting 72 mpg and closer to real-life affordability thanks to product, process, and material innovations.

DCX‘s PNGV Journey

Arguably, one of the primary reasons why Daimler bought Chrysler was because of the damned clever designers and engineers in Auburn Hills, people whose imaginations are running on all cylinders. . .

Arguably, one of the primary reasons why Daimler bought Chrysler was because of the damned clever designers and engineers in Auburn Hills, people whose imaginations are running on all cylinders. . .or perhaps on some alternative power plants. From the original LH vehicles to the current PT Cruiser, these folks aren’t just pushing the envelope, they’re redefining it. So as work proceeds at all of the Big Three companies on trying to develop vehicles that meet the efficiency and capability goals set by the Partnership for a New Generation of Vehicles (PNGV), it isn’t surprising that DaimlerChrysler (DCX)is coming up with creative approaches.

They rolled out the ESX in 1996. In 1998, it was the ESX2. And this year, they’ve created the ESX3.

To be sure, there are incremental improvements in the technology. But one of the vexing issues with creating high-mileage (the PNGV goal is 80 mpg; ESX3 gets 72 mpg), family-sized vehicles is that because there is plenty of know-how and capacity existing to design, engineer and produce lower-mileage vehicles, the developing vehicles just cost a whole lot more than even, perhaps, the most environmentally correct consumer is likely to part with. Tom Gale, DCX executive vice president-Product Development and Design, said, “At DaimlerChrysler, we always have our eye on the consumer. While we’ve achieved tremendous gains in fuel efficiency with the ESX3”—the ESX2 achieved 70 mpg; the ESX eked out 55 mpg—“we’ve put that technology in a dynamic design that is clean and safe, that has the comfort, utility and performance consumers demand—and is closing in on affordability.”

Cutting Down Costs. With regard to costs, they’ve moved in more than increments. The accountants had calculated that the 1996 ESX would cost the consumer $60,000 more than a conventional car. By 1998, the ESX2 had a potential sticker that was somewhat less shocking: a differential of $15,000. The ESX3 is getting a whole lot closer to conventional financing: a difference of about $7,500 compared to, say, an Intrepid. (Of course, the way that gas prices are going of late, a 72-mpg full-size car that retails for $7,500 above a gasoline-powered vehicle may not seem so expensive.)

Not surprisingly, materials are making a major difference in terms of the efficiency of the ESX3.

Making a Mybrid. First, under the hood there is what they’re calling a “mybrid” powertrain (which sounds a whole lot better than “mild hybrid electric”). This has three elements: a three-cylinder, 1.5-liter, direct-injected diesel engine. This is all-aluminum, block and head. It weighs less than 250 lb. The engine, built by Detroit Diesel, is mated with an electric motor system developed by Delphi Automotive Systems that has a peak-power rating of 15 kW. The air-cooled motor weighs 76 lb. Then there is a battery. Batteries have been a problem for alternative vehicles for the simple reason that they generally have a bad power-to-weight ratio: they weigh a lot and don’t have long-lasting oomph. But the ESX3 has a lithium-ion battery pack from French supplier SAFT that weighs in at 106 lb., has a voltage of 165 V, and provides a peak power of 21 kW.

Elastomers play an important part in the suspension system. Tenneco Automotive (which is also supplying GM and Ford with suspension systems for their PNGV-approaching vehicles) has engineered what it is calling the Elastomeric Torsional Axle: instead of conventional springs and the associated mounts and brackets, there are simple, patented elastomeric spring elements that can be tuned for ride and handling.

The exhaust system, which contains an integrated supplemental heat exchanger, is aluminum; it was developed by Arvin Industries.

Sparse But Safe. Then there is the “sparseframe” (as noted, these DCX folks are clever, even in their lexicon). This describes lightweight, thin, aluminum tubular sections that are combined with structural foam and injection-molded thermoplastic body sections. A few notable aspects. One is that there are far fewer pieces making up an ESX3 body than that of a conventional car: 12 versus something on the order of 100. It should weigh 46% less than the conventional, and cost 15% less to manufacture than a metal body. The vehicle meets all federal safety standards. (The physical ESX3 isn’t built with injection-molded thermoplastic: Metalcrafters (Fountain Valley, CA) crafted the concept with thermosets.)

Note that this isn’t just speculative technology, or something that’s developed because it is something that can be developed. Some of the plastics technology that the DCX engineers are working with on the concepts is being used for a thermoplastic hardtop that will be available on as many as 5,000 of the 2001 model year Jeep Wrangler. Why just tops and not entire thermoplastic bodies? Because they are still working on ways to provide a high-gloss surface color without paint.

The glass, from PPG Industries, is solar-reflective: the objective is to minimize the amount of heating and cooling required as HVAC can be power drains.

Green Inside. Inside the car, the interior, primarily provided by Johnson Controls (JCI), there are plenty of plastics, as is the case with conventional cars today. Among the plastics employed are a recyclable expanded polypropylene (EPP) that’s used for the instrument panel. The headliner substrate is a polyethylene terephthalate (PET), a widely recycled material. There is a proprietary material used for the door panels called EcoCor that, according to JCI sources, “contains significant amounts of fiber recycled from consumer and industrial uses.”

The front seats that JCI is providing for the ESX3, called TechLight, are, as their name implies, light, thanks to the use of tubular aluminum frames and aluminum cushion pans.

The ESX3 tips the scales at just 2,250 lb.; it is more than 80% recyclable.

In 1993, what was then Chrysler, GM, Ford, and the U.S. government started on the PNGV road. They’re supposed to arrive at the end on the road in 2004, when PNGV production prototypes are to be ready. Whether that happens or not, it is clear that many of the technology developments will find their way into vehicles of all types and sizes—including those that aren’t mybrid-powered and that lack sparseframes.—GSV

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