Volkswagen has announced the first long-range test drive of its innovative HY.POWER fuel-cell car. On the same mountainous journey, Volkswagen also successfully tested a high-tech Jetta Turbo Direct Injection diesel using a super-clean synthetic diesel called SunFuelÂ®. 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 companion vehicle on the test was a Volkswagen Bora TDI (known as Jetta in the U.S.) 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 Bora 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.
The Volkswagen Bora 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 6,500-foot high Simplon Pass linking France with Italy for this severe test. 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 Bora 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 Bora. The objective was satisfied in full during the journey.
But that was not all. The Bora 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. In other words, the fuel cell is able to convert chemical energy in the form of an oxidation process directly into electrical energy. This is why we speak of “cold combustion” because no ignition or other form of flame is needed, and the “exhaust” consists of nothing more than water vapor.
Almost all fuel cells currently on the market use a type of membrane that is relatively expensive to manufacture. The Bora 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 second innovation that exceeded expectations was the installation of two “supercaps” in the prototype. These are high-efficiency electrical energy storage devices that can be used to supply the traction motor with up to 30 additional kilowatts of power for short periods — for example, rapid acceleration when climbing a steep mountain pass. Volkswagen and PSI have thus taken a big step toward the long-term objective of making fuel-cell vehicles suitable for day-to-day use, fun to drive, and producing them at a price that the average consumer can afford. Viewed in this light, the Bora HY.POWER wrote the opening words in a new chapter of automobile history when it crossed the Simplon Pass.