Auto Service World
News   February 6, 2002   by Auto Service World

Volkwagen Concludes High Altitude Alternative Fuel Test

Volkswagen has announced the first long-range test drive of its innovative HY.POWER fuel-cell car and a test of a clean diesel technology.
In addition to the hydrogen powered test, Volkswagen successfully tested a Jetta Turbo Direct Injection diesel using a super-clean synthetic diesel called SunFuel. SunFuel is a non-traditional low-sulfur fuel that can be made from renewable sources such as plants, waste products and other raw materials. Both cars were tested in the depths of winter and driven over the demanding 6,578-foot high Simplon Pass that connects Switzerland and Italy.
Together with the Paul Scherrer Institute in Zurich, Switzerland, Volkswagen developed a low-cost hydrogen fuel cell with extra high performance “supercaps,” or ultra capacitors, that can store a fuel-cell engine’s electrical energy for use during strenuous driving, such as passing on upgrades. These supercaps eliminate the need for heavy energy storage batteries that are a problem with many other experimental hydrogen vehicles being tested.
The Volkswagen HY.POWER prototype, which does not use a reformer, obtains its energy from on-board hydrogen to create a hydrogen fuel cell — fuel cells generate electricity through a chemical reaction between hydrogen and oxygen. Fuel cells that use hydrogen offer zero emissions and fuel cells that use gas with reformers offer near-zero emissions. The goal of Volkswagen Research and the energy experts at the Paul Scherrer Institute (PSI) was to test a totally new type of hydrogen fuel cell driveline at outside temperatures below the freezing point, hence the choice of the mountain pass. Below zero temperatures and steep gradients are a major challenge to a system with an electric traction motor driven by “cold combustion” of the hydrogen fuel — a more severe test than has ever been attempted before.
The Jetta HY.POWER’s electric motor is rated at 75 kW (102 bhp) and obtains its power from a fuel cell that discharges only water vapor to the atmosphere when it is in operation, continuing its ability to deliver a plentiful supply of energy to the motor. The Volkswagen prototype tackled this high mountain pass just as dynamically as a production car of similar power rating. The objective of the test was to “tune” the fuel cell driveline so that its performance and road behavior was entirely capable of matching a standard production model.
The Jetta HY.POWER incorporates two significant technical innovations. One is the new membrane used in the fuel cell. The other involves the high performance “supercap” capacitors. This was the first opportunity for this new hydrogen fuel cell driveline, which combines lower cost with greater power output, to demonstrate its capabilities in practice. The key to the progress that has been made in both important areas is the membrane located between the anode and cathode of the fuel cell. Inside the cell, hydrogen and oxygen react together through this thin membrane, with water as the by-product. This reaction creates energy.
Almost all fuel cells currently on the market use a type of membrane that is relatively expensive to manufacture. The Jetta HY.POWER, on the other hand, represents the first appearance of the new membrane developed by PSI, which performs very well and is less expensive to produce.
The companion vehicle on the test was a Volkswagen Jetta TDI (Turbo Direct Injection) diesel that used SunFuel. Volkswagen believes this fuel, which offers the lowest particulate emissions possible today, could be used in future near-zero emission fuel-cell cars that use a reformer device to convert regular gas or diesel fuel into hydrogen. Within Volkswagen’s fuel strategy, the SunFuel vehicle represents one of the first steps toward the introduction of a desirable production fuel cell car that could potentially be filled up at a local gas station.

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