Driving Daimler’s Fuel Cell NECAR 4
By Ron Cogan
Green Car testers had the opportunity to closely follow the NECAR (New Electric Car) fuel cell development program at Daimler, and then DaimlerChrysler, over many years. At times the industry’s most high-profile hydrogen program, the NECAR’s development seemed to gather significant momentum in a very short period in the early- to mid-1990s. The progression from using a commercial step van as the NECAR’s initial platform to moving on to a standard minivan was advancement enough. Then, DaimlerChrysler made a real statement by incorporating its hydrogen fuel cell powertrain in a tiny Mercedes A-Class. This article is reprinted verbatim from Green Car Journal’s July 1999 issue to share the editors’ perspective on how far DaimlerChrysler had progressed with its fuel cell technology.
DRIVING DAIMLERCHRYSLER’S NECAR 4
ORIGINALLY PUBLISHED JULY 1999 Make no mistake about it: Driving DaimlerChrysler’s NECAR 4 fuel cell concept is a significant step up from riding as a passenger in its predecessor, the NECAR 3. While both concepts are based on the tiny Mercedes-Benz A-Class, the latest iteration has lost the loud air compressor whine inherent in the older version, creating the kind of near-silent cabin one expects when driving an electrically powered vehicle.
Another significant difference is that DaimlerChrysler is now confident enough in its high-tech product’s driveability to allow someone besides a Daimler engineer behind the wheel. This is not always the case with proof-of-concept vehicles. Green Car editors had previously experienced the NECAR 2, 3, and 4 variants during ride-along sessions in Germany as Daimler’s fuel cell development program progressed.
The break from tradition occurred in a recent U.S. rollout of the NECAR 4, attendant with press demonstrations in Washington, D.C., and in Los Angeles and Sacramento, Calif. Green Car testers drove the NECAR 4 at both West Coast events and found its fuel cell powered performance quite comparable to internal combustion engine drive in acceleration and handling, and importantly, in comfort.
Green Car editors rode along in the NECAR 2 several years ago in Berlin, and the NECAR 3 last year at Daimler-Benz’ headquarters in Stuttgart, Germany. In both instances, Daimler staff drove and verbally walked observers through the experience. One of the most significant technical nuggets gleaned from that adventure – other than the realization that Daimler is serious in its effort to be the world leader in fuel cell research, development, and innovation – was that the air compressor noise inside the cab was so loud that a rear seat passenger had trouble hearing the Daimler driver talking. This developmental issue has now been resolved.
The NECAR 4, which boasts more interior room than the NECAR 3 due to packaging efficiencies, is powered by liquid hydrogen stored in a cryogenic cylinder beneath the floor of the rear cargo area. Storage space is compromised in the rear but legroom in the back seat is surprisingly generous and comfortable. The fuel is processed by a proton exchange membrane (PEM) fuel cell.
The fuel cell’s power output has increased 40 percent over that of the NECAR 3 without a commensurate increase in fuel cell system weight. Engineers at DBB Fuel Cell Engines GmbH – the joint subsidiary formed by DaimlerChrysler, Ballard Power Systems, and Ford Motor Co. – also have managed to squeeze 30 percent more energy from the same size fuel cell system as the one used in the previous fuel cell powered NECAR 2 variant. Daimler claims that energy density (the amount of energy generated per unit of weight) has been increased by 15 percent in the NECAR 4.
NECAR 4’s roots date back to 1994 when Daimler-Benz introduced the NECAR 1, a veritable rolling laboratory in the form of a commercial van with a fuel cell power unit weighing in at more than 360 pounds. This early fuel cell system required the entire cargo area of the Mercedes-Benz van, allowing enough room for only a driver and front-seat passenger.
Two years later the fuel cell power unit’s size was significantly reduced and integrated into a Mercedes V-Class vehicle – with a resultant look similar to a conversion van – leaving room for up to six passengers. NECAR 2 had a top speed of 68 mph and a range of 148 miles.
NECAR 3 emerged on the scene in 1997 after Daimler had introduced its NEBUS fuel cell bus. This third generation fuel cell vehicle boasted a platform change to the smallish A-Class and an onboard hydrogen gas production system using methanol. By using methanol as fuel, an onboard reformer separates hydrogen from the other gas molecules, leaving no residual particulates, oxides of nitrogen, or sulfur dioxide. Although this method does create some emissions, it still results in emitting 30 percent less carbon dioxide than conventional gasoline fuel cars.
While the current NECAR 4 does use liquid hydrogen as its fuel, this is a temporary concession to providing substantial enough driving range to allow the NECAR 4’s use in field trials with the State of California. DaimlerChrysler makes it no secret that it intends to pursue methanol as its fuel of choice for the mid-term.
Want to know more about fuel cell vehicles? Be sure to check out these articles on GreenCar.com:
VW Conjures Up a Hydrogen Powered Microbus
Honda FCX Clarity and Home Hydrogen Fueling Stations
GM and Honda Hydrogen Fuel Cell Vehicles
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