Volkswagen Touran EcoFuel Natural Gas Car

Natural gas is growing in popularity in many regions of the world, including Germany where natural gas vehicles (NGVs) are served by over 700 natural gas stations now in operation. This focus on natural gas will continue with 1,000 stations planned by the end of 2007 and a total of 1300 by 2008. Ultimately, the goal is 12 miles (20 kilometers) or less between natural gas refueling stations.

The German government supports natural gas with substantially lower taxes, just a few percent of the rates for diesel and gasoline. When compared on an equivalent energy basis, natural gas costs about half as much as gasoline and about 70 percent as much as diesel. Energy providers and municipalities also subsidize NGV purchases.

Addressing this market, Volkswagen offers its popular Touran EcoFuel MPV, and now an EcoFuel taxi variant. Powered by a 109 horsepower, 2-liter four-cylinder engine, VW calls this a “quasi-monovalent” natural gas powerplant because it runs on either compressed natural gas (CNG) or gasoline. We just call it bi-fuel and convenient, since switching to gasoline is automatic when the CNG tanks are empty.

Since the engine has a 13.5:1 compression ratio for optimum efficiency when running on CNG, this must be compensated for when running on gasoline. VW deals with this higher compression by backing off on ignition timing and throttle valve setting during gasoline operation. The engine is normally started on CNG except at temperatures below 59-degrees F, when gasoline is used. The Touran EcoFuel has a range of 192 miles on natural gas, which is stored in four underfloor tanks to retain full cargo capacity and seven occupant seating. Generous-sized lines and valves enable fast and quiet refueling comparable to that of a gasoline vehicle.

The Touran has top speed of 112 mph. When the EcoFuel engine is operated in natural gas mode it generates 80 percent less carbon monoxide than a comparable gasoline engine. Nitrogen oxides are reduced by 80 percent and hydrocarbons by 73 percent. It gets an average of 41 mpg on natural gas.

Green Car editors had the opportunity to test drive the Touran EcoFuel in Spain and found it to provide a very seamless driving experience, as one would expect from Volkswagen. Those on the commercial side are also accommodated since the same bi-fuel engine is also offered in the VW Caddy EcoFuel commercial van.