TDI ENGINE & FUEL ECONOMY

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The New 1.9L TDI UltraModern Diesel Engine in North America

With the introduction of the New Beetle, Jetta IV, and Golf IV with the newly designed A4 chassis into the North American market, Volkswagen is offering the next generation of the 1.9L TDI engine. The 1.9L TDI engine has been completely redesigned for the New Beetle as well as all other models in the newly defined A-platform chassis, which includes the new Golf, the new Jetta, the Audi A3, and the Skoda Oktavia. Several evolutionary changes have been made to the TDI concept to further improve its emissions, efficiency and performance for North America. Emissions performance is improved with increased fuel injection pressure, optimized fuel injectors, calibration modifications, EGR cooling, refined piston ring placement, and reduced crevice volume in the combustion chamber. Efficiency is improved with a new oil pump and water pump to include a modified oil circuit to reduce friction and increase oil pressure buildup especially for cold starting. A new vertical oil filter has been installed for ease of maintenance with a fully incineratable cartridge for recycling. A new cylinder head cover is installed with an integrated oil separator to minimise oil consumption. Performance and efficiency of the new TDI engine is much improved with the addition of a Garrett GTVNT15 variable geometry turbocharger, which increases torque at lower engine speeds while preserving performance at higher engine speeds. The engine/gearbox assembly has also been reinforced with the introduction of pendulum engine mounting support to reduce vibration.

Modifications for the American Market differing from Europe

The basic engine for use in Europe had to be modified for the American market and further developments incorporated to satisfy conditions as these:
-Stringent emission limits applying to diesel engines in California
-OBDII diagnostic with digital trouble codes integrated with Siemens 80C167 microprocessor containing 16/32bit extended instruction set for communication with CAN bus communication system
-Special topographical and climatic useage conditions relative to North America
-Subquality fuels and lubricants with unfavorable properties for diesel injection pump Bosch Model VE VP 37 distributor pump operating pressure 850 bar

The full load values of the American market TDI is achieved by Volkswagen to deliver a torque of 149Nm at 1,000rpm and reaches its maximum value of 210Nm at 1,900rpm. Of particular note are the low full-load smoke emissions and specific fuel consumption values of less than 200 g/kWh. The implementation of technical software improvements in the BOSCH ECU made it possible to meet US and Canadian emission requirements with minimum loss of power as compared to the European TDI version. An extremely high level of efficiency is achieved at part load with a specific fuel consumption of 197 g/kWh making the TDI one of the most fuel efficient engines of its class. Particularly economical driving is possible in the low part-load range which is frequently used in practice where only 350g of diesel fuel is consumed per kilowatt-hour at an engine speed of 2,000rpm and a mean effective pressure of 2 bar. Maximum output of 66kW at 3,750 rpm is attained with a volumetric efficiency of 34.8 kW/! at a maximum mean effective pressure of 14 bar. Piston speed is rated at 12.7 m/s maximum rpms.


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99 JETTA TDI HERR WETTERAUER TORQUEMEISTER
98 KAFER WETT SPEKTAKULARE TURBOKOMPRESSOR
97 KTM 620 ADVENTURE RALLY PARIS-DAKAR SUPER THUMPER
 
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SkyPup

Guest
The fuel map in the BOSCH ECU programmed at the Volkswagen factory shows that the maximum economy of the TDI engine is reached just slightly above the maximum torque production rpms or right between 1,900-2,000rpm for all those out there searching for the maximum mileage possible. Keeping engine rpms in this range will result in the lowest possible fuel comsumption per distance traveled.
 
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SkyPup

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Anyone wishing to order a copy of this SAE paper, here is the description:

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Document Number: 981950
Title: The New Diesel Engine in the New Beetle

Meeting Where Presented:
Future Transportation Technology Conference & Exposition, August 1998, Costa Mesa, CA, USA, Session: Diesel Engines for Trucks and Cars in 2004


Author(s):
D. Bosch - Volkswagen AG
S. Hunkert - Volkswagen AG
U. Dorges - Volkswagen AG
G. Goergens - Volkswagen AG
J. Liang - Volkswagen AG
 
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