TODAY 20 JUN Exclusive Audi News

...International Motor Show. Ever since, the brand with the four rings has continued to increase its lead and set many milestones. Since 1989, Audi has produced over five million TDI engines and is now marketing a wide range of leading-edge power units. They combine great propulsive power, sporty driving enjoyment and exemplary efficiency, and demonstrate that this technology also holds great potential for the future. Audi has been building diesel engines for over 30 years, the first of which was a five-cylinder unit with swirl-chamber injection that made its debut in 1978. 11 years later, the brand made a technological breakthrough that revolutionized the diesel market. Under the abbreviation TDI, direct injection, turbocharging and totally electronic engine management were combined to create an entirely new dimension of powertrain technology.

Since then, the Audi brand’s engineering advances have propelled diesel engines to an undreamed-of technological boom and overwhelming market success. The TDI from Audi had put an end once and for all to the old diesel image as “lame, loud, and dirty” and turned it into the opposite. Today nearly every automaker includes this technology in its program.

“20 years of TDI means 20 years of progress and dynamic change, sporty power and efficiency,” says Michael Dick, Member of the Board of Management for Technical Development at AUDI AG.

“The TDI has been a key factor contributing to the advance of our brand into the premium segment. It has become the world’s most successful efficiency technology that is unsurpassed in the relation of power output to fuel efficiency."

The father of the Audi brand’s TDI technology is Richard van Basshuysen, who recognized its enormous efficiency potential with the 1973 oil crisis still fresh in mind. As the pioneer of this technology, he pushed through the development of the electronically controlled diesel engine with turbocharged direct injection despite considerable resistance.

“The program was launched in 1976,” says van Basshuysen. “What we set out to achieve was to develop an internal combustion engine with the lowest possible fuel consumption. We checked out all conceivable concepts all the way to a two-stroke diesel engine, and in the process analyzed and improved diverse injection and combustion methods.” Among other awards, van Basshuysen received the highly prestigious Ernst Blickle Prize in the year 2000 for his “achievements with regard to the design and development of the direct-injection diesel engine for the passenger car.”

One of his employees from those early days is Richard Bauder, who now heads the Audi company’s diesel engine development.

“One of the big breakthroughs was the dual-spring injection-nozzle holder, which allowed the pre-injection of smaller fuel amounts. The result was smoother combustion and improved acoustics – the fundamental requirements for use in passenger cars."

The first TDI was a huge success right from the start. When installed in the third-generation Audi 100, the five-cylinder engine’s 2,461 cc displacement achieved 88 kW and 265 Nm of torque, the latter at 2,250 rpm. A distributor-type injection pump sprayed the fuel into the combustion chambers.

A pioneering achievement: Top speed of nearly 200 km/h, fuel consumption of 5.7 l/100 km

As the engine went into production in the Audi 100 Avant late in 1989, its muscular power marked the dawning of a new era. At that time, diesel engines were considered economical and durable but rather dull performers. However, with a top speed of nearly 200 km/h, the Audi 100 2.5 TDI propelled its way into the ranks of fast touring sedans, also featuring enormous acceleration from zero and amazing fuel economy of 5.7 litres of diesel fuel/100 km – established in line with the valid standards at the time. What’s more, the car’s travel range between refills was very generous.

In the midsize class too, TDI engines from Audi began to triumph. Starting in 1991, the Audi 80 was powered by a four-cylinder, 1.9-litre diesel unit that delivered 66 kW and 182 Nm. Four years later, an upgraded version with 81 kW was added. The increase in power was mainly due to the use of a new turbocharger with adjustable guide blades on the exhaust side: The so-called VTG charger with variable turbine geometry enabled torque to be boosted smoothly and promptly, even from very low engine speeds.

In 1993, the brand with the four rings converted its entire diesel program to TDI engines, and then in 1994 Audi took the next step: The five-cylinder unit was upgraded to 103 kW. A six-speed transmission became the production model, and for the first time the TDI was combined with permanent all-wheel drive – in the first TDI quattro. With 290 Nm of torque at 1,900 rpm, 208 km/h top speed and 9.9 seconds for the standard acceleration test from standstill, this car almost instantly became a sensation. The TV spot with the question “Where’s the tank?” made it legendary: The A6 TDI covered a distance of up to 1,300 kilometres on a single tank of fuel.