2009 Volkswagen Jetta TDI SportWagon and Volkswagen Tiguan (H2 Fuel Cell) HyMotion Prototype Preview
By Carey Russ
While Japanese and American automakers tout gasoline-electric hybrids as the solution for high fuel economy, Europeans, represented in the US by the Germans, see diesel as the way. And, with the availability of low-sulfur diesel fuel, the newest generation of clean diesels will be sold throughout the country for model year 2009. Yes, even in California and states that follow its lead in emissions requirements.
But beyond hydrocarbon-based fuels, be they gasoline, diesel, or natural gas, lies hydrogen. Hydrogen is the most common element in the universe. Unfortunately, that's because most of the hydrogen in the universe is locked up in stars and interstellar gas clouds - not exactly useful resources for vehicle fuel. Most of the hydrogen on Planet Earth is locked up in water, molecules of which are made of two hydrogen atoms and one oxygen atom. However, persuading a water molecule to break apart currently requires more energy than could be released using that hydrogen. And that energy has to come from somewhere - which, in practical current terms means a fossil fuel-burning power plant. Not much of a reduction in dependence on fossil fuels there.... Hydrogen is currently most commonly extracted from hydrocarbons - like oil and natural gas. Both are better used directly, or with less refining, as fuel themselves than as mass hydrogen sources.
So the path to independence from fossil fuels has a way to go yet. That has not prevented nearly every automaker in the world from development of hydrogen fuel cell-powered electric vehicles. Why fuel cells instead of batteries? A fuel cell can be filled with hydrogen in a similar manner to filling the fuel tank of a car with gasoline or diesel. Unlike a battery pack, there is no wait for charging. And the only waste product of a fuel cell is water.
The negatives? Fuel cells are expensive. They have been in use quite a while, in, for one example, satellites. Not reasonably-prices consumer items. And early fuel cells required considerable care and large cooling systems. Refinement has taken place, and a fuel cell system can easily fit into a car today. There are fuel cell vehicles currently on the road. Besides experimental vehicles from many manufacturers, Honda has just made the futuristic-looking FCX Clarity available for "beta-test" lease in "select Southern California areas." Move over, Prius, the Clarity is the new darling of the Hollywood green set. Why "select Southern California areas" besides the obvious Hollywood connection?
Because that's where Honda's US base is, so they can keep a close eye on the vehicles. More importantly, there is a hydrogen-refueling infrastructure in the LA Basin. A small one, so Clarity drivers won't be going too far from home, but infrastructure nonetheless. There are also hydrogen filling stations in the San Francisco area, and in Sacramento, the state capital (and home of the California Air Resources Board). But outside of a few metropolitan areas? Zilch. Fuel cell vehicles are not quite practical transportation at the moment.
Volkswagen has been working on fuel cells for a while now, and recently showed its latest development to the American press in San Francisco, CA. The Tiguan HyMotion is based, obviously, on VW's new Tiguan crossover,which has ample room for the fuel cell stack and its associated cooling system in the engine compartment. A lithium-ion battery pack stores energy generated during regenerative braking, and can add an assist to the fuel cell stack when required. The fuel cell stack is capable of 107 horsepower, with up to 134 hp available with battery assistance. Hydrogen is stored under 700 bar (10,000 psi) pressure in a tank underneath the rear of the rear seat and the front of the cargo area made of the same carbon-fiber/kevlar material used for jet fighter fuel tanks. The tank stores 3.2 kilograms of hydrogen, approximately the equivalent of 3.2 gallons of gasoline. Mileage, according to VW, works out to the equivalent of 42 to 62 mpg, considerably more than a gasoline-powered front-wheel drive Tiguan.
The Tiguan HyMotion is an experimental vehicle. It runs, but it didn't run the day I looked at it. There was a rumor that members of the press would be able to drive it, or at least ride in it, but then it was announced that a software problem prevented the vehicle from running... on the other hand, trust anyone to drive a multi-million dollar experimental vehicle in San Francisco traffic? Um, this is a city where red lights are considered advisory, and often ignored. Where pavement can look more like the Rubicon Trail than actual pavement. And where traffic can sometimes move at the speed of twenty feet an hour. Plus thirty or so journalists and one vehicle? Look up "komodo dragon feeding scrum" to see what that can look like...
Volkswagen sees fuel cell component durability and, most importantly, a functional fueling infrastructure as the greatest challenges before bringing a fuel cell vehicle to market. Tank size and range are also issues. When fuel is readily available, VW will be ready. But they suspect that could still be a decade away.
Meanwhile, VW diesels are back. More specifically, Jetta diesels, in both sedan and Sport Wagen body styles will be available nationwide this Fall. And there was a Jetta TDI sedan available for testing, so I braved the traffic and availed myself.
The adjectives that come to mind are "refined", "quiet", and, especially, "torquey". Other than a slight hesitation off idle as the turbo spooled up - which could easily be compensated for by use of a manual transmission instead of the automatic in this particular vehicle, and which wasn't really a serious issue - it was nearly perfect. I'd take the TDI drivetrain over the 2.5-liter gasoline engine - or even VW's lovely 2.0-liter gasoline direct-injection turbo.
Gasoline-electric hybrids make sense in city driving and stop-and-go commute traffic, but offer little advantage at speed on the highway. Diesels shine on the open road, with 45 to 50 mpg available easily from a car the Jetta's size. If you must commute (don't say you like it, I know you're lying) then a hybrid will do. If you can connive to miss the worst of the traffic, you'll do better with a diesel.