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Go Back   TDIClub Forums > VW TDI Discussion Areas > TDI Power Enhancements

TDI Power Enhancements Discussions about increasing the power of your TDI engine. i.e. chips, injectors, powerboxes, clutches, etc. Handling, suspensions, wheels, type discussion should be put into the "Upgrades (non TDI Engine related)" forum. Non TDI vehicle related postings will be moved or removed. Please note the Performance Disclaimer.

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Old August 31st, 1999, 05:10   #1
SkyPup
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Default VW DIESEL HISTORY

THE DEVELOPMENT OF THE VOLKSWAGEN TURBOCHARGED DIRECT INJECTION (TDI) DIESEL ENGINES

This story is about the development of the first diesel engines at VOLKSWAGEN AND AUDI, which led to the first totally electronically controlled turbocharged diesel engine produced by Audi for incorporation in the AUDI 100 passenger car in 1990. This 5-cylinder AUDI TDI is the forerunner of the modern day Volkswagen TDI. The story covers parts of the early development of the first passenger car diesel engines leading up to the AUDI 5-cylinder. This story will be continued and updated as time goes on. Future installments will include the developments made through the production of the A3 TDI engine as well as the A4 TDI in the future, including the technological achievements of direct high pressure fuel injection and electronic vehicle management.

In the fall of 1976, Volkswagen introduced its first 4-cylinder Diesel engine, a swirlchamber design with a stroke of 80mm and a bore of 76.5mm, giving a displacement of 1471cc. The nominal power was 50HP at 5,000 rpm. Two years later, in 1978, the development of a 5 and 6-cylinder Diesel engine was completed. All 4,5,and 6 cylinder Diesels used the same combustion system. Thus, in addition to the powerplants for the Volkswagen Rabbit and Dasher vehicles, Diesel engines became available for the AUDI 5000 and the Volkswagen Truck. Since 1979, the 6-cylinder Diesel engine has been sold to VOLVO for a passenger car application.

In the fall of 1980 the engine displacement of the 4-cylinder was increased by lengthening the engine stroke from 80.0 to 86.4mm. Nominal power was increased to 40Kw or 54HP at 4,800 rpm with the maximum torque of l02Nm at 2,000 rpm. At this time, the longer stroke required a new connecting rod design and the distance between the connecting rod bolts was increased to 61.5mm. The piston pin diameter was also increased from 22 to 24mm. The small end bearing became a common part with the future 5 and 6ócylinder Diesel engines.

The last development of the naturally aspirated Diesel engine was concluded in early 1981 with an application to the Volkswagen Transporter and MicroBus. Engine power had been changed to 37Kw at 4,200 rpm. The demand for this naturally aspirated Diesel engine increased significantly so that in the first six months of 1981, 2,600 naturally aspirated Diesel engines were produced every day which represented 40% of the total production of water cooled engines in the Volkswagen Corporation.

MAIN DESIGN FEATURES:

The 4-cylinder Turbocharged Diesel Engine was designed as the powerplant for 5 vehicle models of VOLKSWAGEN AUDI production. The engine is transversely mounted in the Rabbit and Jetta vehicles. The engine is mounted longitudinally across the front axle in the Dasher, Quantum, and Audi 4000. Because of different space restrictions in the engine compartments, the turbocharger unit is mounted in two different locations. The power and torque are identical in both instances, nominal power is 51Kw or 7OHP at 4,500 rpm with maximum torque of 133Nm at 2,600 rpm. The engine displacement of 1599cc results from a bore of 76.5mm and a stroke of 86.4mm. The compression ratio is 23:1.
The turbocharger unit is adapted to small displacement Diesel engines. Turbochargers from Garrett Air Research and Kuhnle Koop and Kausch (KKK) are used. The turbine housing material has been optimized for the high exhaust temperatures encountered. In the case of excessive boost pressure, the wastegate opens and the turbine receives only a portion of the hot exhaust gases while the remainder flow directly into the exhaust pipe. As a result, turbine and impeller speed are reduced and the designed boost pressure is maintained. Turbocharger boost pressure begins to develop at 1,400 rpm and is regulated with a maximum wastegate movement of 10mm. At 0.6 bar the wastegate actuator remains closed, at 0.8 bar the wastegate actuator is opened one half maximum at 5mm, and at 1.0 bar the wastegate actuator is opened the full 10mm, thereby regulating the boost pressure to about 0.8 bar throughout the turbochargers operational range. Boost pressure development of the turbocharger allows a Pressure Ratio (P2/Pi) of 1.1 at 1,400 rpm, 1.3 at 2,000 rpm, 1.5 at 3,000 rpm, and 1.7 maximum at 4,000 rpm. This corresponds to a full load boost pressure of 0.8 bar from 2,220 rpm to 3,750 rpm. Being as the turbo boost pressures were held to an average max. of 0.8 bar, a charge air cooler (intercooler) was not needed to lower the intake air temperature. Turbine inlet and exhaust temperatures did not exceed 820 degrees C. at maximum load.

The oil circuit had to be adapted to the specific needs of the engine because of the higher thermal loading due to the turbocharger. In addition to conventional pressurized lubrication, oil lines with upwards directed jets are mounted in the crankcase at each cylinder to provide additional cooling of the piston bottoms. Also, the oil cooling and lubricating the turbocharger flows back into the oil pan via a flexible tube. Oil pump capacity has been increased 15% as well. The special oil cooling adapted to the piston bottoms has resulted in lowering the critical piston temperatures by approximately 30 degrees C. Because of the turbocharging also causing higher exhaust valve temperatures about 100-150 degrees C. higher than normal aspirated Diesel, a better exhaust valve material was applied as well as for the valve seats.

An increase in stiffness between the cylinder head and the engine block as well as a change in the tightening procedure were essential modifications for the turbochargered Diesel engine. Cylinder head bolts are increased from 11mm to 12mm along with deck thickness. Extensive testing was done to optimize the cylinder head gasket in conjunction with the cylinder block modifications. The cylinder head gasket has to give reliable sealing for combustion pressures up to 130 bar with a sealing land of only 6mm. The cylinder block and head were also designed to withstand combustion pressures of up to 130 bar. The limiting value for turbocharger boost pressure on a diesel engine is peak compression pressure, which has been limited to 130 bar on this engine.

This four cylinder VW AUDI TURBOCHARGED DIESEL engine was superceded by the AUDI 5-CYLINDER 2.5 LITER TURBO DIESEL in 1990 for introduction in the AUDI 100. This engine is the first engine to be built using electronically controlled turbocharged diesel engine management to include electronic throttle pedal and BOSCH VE VP-34 distributor fuel pump under control of the BOSCH ECU. On the AUDI 5-cylinder Turbo diesel a KKK K-16 turbocharger with integral wastegate ensured the buildup of boost pressures even at low operating rpms. This assisted in the good engine response to the accelerator. A charge air cooler (intercooler) was introduced to lower the intake air temperature due to higher boost pressures. The intercooler reduces intake air temperatures by a maximum of 70 degrees C. and its thermal efficiency has been established at 80% with only 80mbar pressure loss throughout.



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99 JETTA TDI HERR WETTERAUER TORQUEMEISTER
98 KAFER WETT SPEKTAKULARE TURBOKOMPRESSOR
97 KTM 620 ADVENTURE RALLY PARIS-DAKAR SUPER THUMPER
ICH LEBE MEIN TECHORAD VW TDI'S MIT DIREKTEINSPRITZER TURBOKOMPRESSOR

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Old August 31st, 1999, 05:25   #2
Dieselworld
Veteran Member
 
Join Date: Mar 1999
Location: Atlanta, GA USA
Fuel Economy: 55 mpg Hwy
Default Re: VW DIESEL HISTORY

Wonderful info!!

This kind of info is what makes this forum a great source of info. Sad to say but most of the content lately on this forum is just idle "chat room talk" not good technical info.

Please post more!!!

Chow
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Old August 31st, 1999, 06:01   #3
SkyPup
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Default Re: VW DIESEL HISTORY

Thanks Russell, I am working on it, it is alot of work, but I'll try to keep adding engineering and technical info to it as I work it up to include the A3-A4 TDI's. It will be primarily a engine design development description, not a whole car thing. I plan to turn it over to Fred to post for historical reference aspects.
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Old August 31st, 1999, 17:37   #4
cdub
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Join Date: Aug 1999
Location: Nassau County, Long Island
Default Re: VW DIESEL HISTORY

Fantastic info SkyPup! Anyone seen anything on the new V6 TDI in Europe? A (relative) "big block" diesel in the Passat may be just the ticket for a lot of American buyers heretofore afraid of diesel. Come on VWoA!

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SeaDub!
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Old August 31st, 1999, 18:07   #5
Ric Woodruff
BANNED, Ric went to Coventry.
 
Join Date: Feb 1999
Default Re: VW DIESEL HISTORY

A "big block" diesel will do absolutely nothing to change mericans "fear" of diesels... keep dreaming like I do.

[This message has been edited by SkyPup (edited September 01, 1999).]
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Old August 31st, 1999, 19:03   #6
mickey
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Default Re: VW DIESEL HISTORY

You want to repeat that please, Ric?

-mickey

p.s. I've said it before: Americans aren't stupid when it comes to diesels, just ignorant. Ignorance can be cured. It'll take time, but we'll get there.
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Old September 1st, 1999, 05:44   #7
SkyPup
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Default Re: VW DIESEL HISTORY

Actually the American BIG THREE dimwits are trying to get in on the diesel act in a BIG way, via Detroit Diesel, Cummins, and Isuzu in oreder to put some big block muscle in their SUVs. The only way to increase mileage in a 10,000-12,000 pound automobile is to use the most efficient engine design in the world - DIESEL, just like in real trucks. I bet it won't be long before these gas sucking V-8 and V-10 and V-12 motors are history, as they well should be. BTW, the BIG THREE are trying hard to get this through the the EPA and the fuel refinery people too, it is their only salvation for the future and they know it.
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Old September 1st, 1999, 06:41   #8
SkyPup
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Default Re: VW DIESEL HISTORY

P.S. RIC'ster, how you can manage to mess up a good thread like this? Perhaps this is the most informative thread to be on this Forum in quite some time now and you screw it up. Do you think you could practice a little more discretion on what to mess up and what not to mess up. In fact, why don't you edit that mess not and get rid of it.

In case you or anyone else is wondering why, I am NOT going to allow this PERFORMANCE FORUM go the chat room way of some other boards on FRED's TDI PAGE. Try to keep the information here cleaner here, please.

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99 JETTA TDI HERR WETTERAUER TORQUEMEISTER
98 KAFER WETT SPEKTAKULARE TURBOKOMPRESSOR
97 KTM 620 ADVENTURE RALLY PARIS-DAKAR SUPER THUMPER
ICH LEBE MEIN TECHORAD VW TDI'S MIT DIREKTEINSPRITZER TURBOKOMPRESSOR

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