Nov 24 2008
Modern diesels are cleaner than ever before. To show how efficient they are, the latest generation made its debut recently on the racetrack proving that even in full race driving conditions diesel vehicles can remain clean and green ... and highly fuel- efficient!
The clean, highly efficient VW Jetta TDI Diesels using a Bosch 'common-rail fuel injection system' with fast, precise Bosch piezoelectric fuel injectors, battle for position at Lime Rock, CT
Thirty new VW Jetta Diesel TDIs, powered by 2.0-liter, four-cylinder engines that produce 170 hp and 258 lb.-ft. of torque, tackled some of the top road racing courses in North America during the Volkswagen Jetta Diesel TDI Cup, a multi-race series of basically stock Jetta 'clean diesels' racing at major road tracks from Lime Rock to Road Atlanta.
"What we have here are virtually stock diesel passenger cars that raced hard throughout the summer and fall, averaging fuel mileage in the mid- twenties and running absolutely clean under very tough full road race conditions," said Wolfgang Hustedt, Motorsports Manager for Bosch, which supplies the advanced fuel system that helps make these vehicles fuel efficient and 'green.'
'Common Rail' - Key to Efficiency
The heart of these clean, highly efficient engines is a Bosch common-rail fuel injection system that uses fast, precise Bosch piezoelectric fuel injectors, instead of a traditional mechanical system. Diesel fuel is pressurized along a "common rail" for delivery to electronically activated injectors for each cylinder. This technology permits higher injection pressures, which better atomize the fuel, enhance performance and make it easier to control pollution.
"This is the stock setup for the VW Jetta Diesel TDI - basically the same engine and car any motorist would get if he picks one up and takes it home - with the addition of racing ABS brakes and suspension," Hustedt said. "This advanced diesel technology allows the vehicle to become the first automobile to meet the world's most stringent emission control standards - California's Tier II, Bin 5," he added.
Fast Acting Injectors Play a Big Role
The latest common rail system relies on highly precise rapidly switching piezo injectors, which have 75 percent fewer moving components and mass, allowing them to switch at double the speed of previous solenoid-valve injectors. This allows the piezo injectors to significantly lower diesel emissions, increase the achievable engine power and noticeably lower engine noise - depending on the specifics of the engine.
"The Jetta TDI diesels operating with this system are very powerful with lots of torque in addition to high fuel efficiency and very low emissions - and they are very quiet," Hustedt said.
"In older diesel engines, the fuel management system was almost entirely mechanical," Hustedt said. "Higher pressures in the new electronically controlled systems allow injectors to deliver finer atomization of the fuel, while improving combustion efficiency and lowering particulate emissions."
To help make it 'green,' in addition to the sophisticated Bosch fuel system components, the Jetta also uses a Noxstorage catalyst, which is basically a reservoir that temporarily holds the noxious emissions like a particulate filter, until they can be burned off during one of the engine cycles.