Fuel efficient and powerful technology with a future. [fimg=right]http://www.cleanmpg.com/photos/data/501/2010_Audi_A3_-_1_6L_TDI_on_Day_1.jpg[/fimg]Wayne Gerdes - CleanMPG - Nov. 20, 2009 Lone 1.6L equipped Audi A3 in Norway while crossing the European continent from north to south at over 70 mpgUS! Audi is celebrating the 20th birthday of TDI technology In the fall of 1989, the Audi 100 2.5 TDI – the first Audi with a direct-injection turbocharged diesel engine – was exhibited at the Frankfurt Auto Show. Ever since, the four rings has continued to set reach new milestones. Since 1989, Audi has produced over five million combining excellent power and exemplary efficiency. Audi has been building diesel engines for over 30 years, the first of which was a five-cylinder unit with prechamber injection that made its debut in 1978. 11 years later, a technological breakthrough revolutionized the diesel market. Under the abbreviation TDI, direct injection, turbocharging and totally electronic engine management were combined to create an entirely new 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 has put an end to the old diesel image as “lame, loud, and dirty”. Today nearly every automaker includes this technology in its model lineup in Europe. “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 Bauder, who continues to head the company’s diesel engine development to this day. The program was launched in 1976 with the 1973 oil crisis still fresh in mind, as Bauder reports. “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. One of our 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.” TDI success By offering 120 HP and 195 Lb-Ft. of torque from a 2.5L five-cylinder TDI engine, the third-generation Audi 100 was an instant success. The engine made its debut in the Audi 100 Avant. At that time, diesel engines were considered economical and durable but rather dull performers. The TDI equipped Avant had a top speed 124 mph placing it squarely into the ranks of performance touring sedans of its day while providing its owners 41.3 mpgUS combined from the older European Drive Cycles. In the midsize segment, TDI engines from Audi began to triumph as well. Starting in 1991, the Audi 80 was powered by a four-cylinder, 1.9-L TDI that delivered 90 HP and 134 lb-ft of torque. Four years later, an upgraded version with 110 HP was added. The increase in power was due to the use of a new for its time, exhaust side variable vane turbocharger. The VTG (variable turbine geometry) enabled torque to be boosted smoothly and promptly from very low engine RPMs. In 1993, Audi converted its entire diesel program to TDI engines, and in 1994 Audi took the next step. The five-cylinder unit was upgraded to 140 HP. A six-speed transmission was standard and for the first time, the TDI was combined with permanent all-wheel drive in the TDI Quattro. With 214 lb-ft of torque at 1,900 rpm, a top speed of 129 mph and 9.8 seconds to 60 mph, the Quattro was an instant sensation. A TV spot with the question “Where’s the tank?” made it legendary: The A6 TDI covered a distance of up to 808 miles on a single tank of fuel. 1997: The first V6 TDI in a passenger car In 1997 Audi initiated another revolution – with the debut of the world’s first V6 TDI in a passenger car. With a four-valve cylinder head, the 2.5L unit delivered 150 HP and 229 lb-ft of torque. Two years later this was followed by the first V8 TDI from Audi. Installed in the A8 with a first, common rail injection. The 3.3L unit offered 224 HP and 354 lb-ft of torque which drove the A8 to a top speed of 150 mph top speed along with quieter operation. Another important new solution was developed for the four. In 2000, a new high-pressure injection system, whose integrated pump/nozzle elements generated 30,000 psi boosted output to 115 HP and later to 130 HP. In the compact class, Audi set another milestone in 2001: The A2 1.2L TDI achieved an average fuel consumption of 78.7 mpgUS combined on the older drive cycles. The compact A2 with its lightweight aluminum body featured a three-cylinder diesel engine with 1.2L displacement. A derivation from its big brother, the 1.4L TDI, it generated 61 HP and 103 lb-ft of torque. The A2 3L TDI was the world’s first five-door car with fuel economy greater than 78.5 mpgUS combined and remains so to this day. In 2003, Audi produced a more powerful cousin of its 1.9L TDI in the shape of the 2.0L TDI. The New generation 3.0L TDI Even in larger engines, Audi was advancing its technological prowess. In 2003, a 4.0L V8 with 275 HP was introduced using new technical enhancements for the V engines. The 3.0L engine with an output of 224 HP was equipped with common rail technology and innovative piezo-electric injectors. These can inject very small doses of fuel, and with their extremely fast opening and closing nature can deliver multiple separate pre-, main- and post-injections. When a voltage is applied to piezo crystals, they slightly expand in a fraction of a millisecond. In the injector, several hundred tiny piezo disks are stacked on top of each other, and the expansion of this stack is transferred directly to the injection needle. Piezo injectors can produce precisely regulated increases in pressure and a uniform combustion process. This advance has brought engine NVH into the region of gasoline engines. Another innovation was a particulate filter to clean the exhaust. In 2007/2008 the new four-cylinder 2.0L TDI was equipped with a common rail system including piezo injectors. In 2009 this became the standard technology in all of its diesel engines. Richard Bauder proudly exemplifies what has been achieved to date: “In 1989 we started out with 13,230 psi of injection pressure; today we’re at 29,400 psi. During this period, our TDI units have increased by more than 100 percent in power output and 70 percent in torque compared to the same displacement of previous generation TDI’s. At the same time, emissions have been reduced by 98 percent.” In the past 20 years, the Audi has produced more than five million TDI engines. Taking all makes into account, the TDI principle today powers over 50% of all vehicles in Europe today. The TDI units marketed by Audi today are clean, efficient, dependable, refined, comfortable, and powerful. In motorsport, the world’s toughest test lab, they are proving how closely efficiency and dynamics are related. [fimg=left]http://www.cleanmpg.com/photos/data/501/Audi_R15_Peugeot_908.jpg[/fimg]An Audi R15 TDI leading its arch rival, the Peugeot 908 HDi at the 2009 12-hours of Sebring The R10 TDI whose V12 diesel engine delivers more than 650 HP, has won the Le Mans 24 Hours three times in a row starting in 2006. Its successor, the R15 TDI with a V10 TDI turbo-diesel engine, has been earning top rankings right from its debut in 2009. In production cars, the 2.0L TDI with up to 170 HP and 258 lb-ft. of torque is another athletic engine. It delivers power and refinement, and thus lends brilliance to the dynamic TT and the TT Roadster. The lightweight, mainly aluminum bodies of this model series contribute to its superior driving performance: The TT Coupé, with Quattro permanent all-wheel drive accelerates to 60 in under 7.5 seconds with a top speed of 140 mph. more importantly, it does so while offering its owners a 44.4 mpgUS combined rating on the NEDC. Improving fuel economy Diesel engines thanks to their thermodynamic properties utilize a given fuels energy content especially well. Adding to that efficiency, technologies from Audi’s modular efficiency platform further amplify this effect. Intelligently managed subsystems such as a demand-controlled oil pump consume less energy. Sophisticated production methods reduce friction within the engine. In many TDI units, laser beams are used to perfectly smooth down the cylinder paths. This makes them last even longer, further reduces oil consumption and reduces stresses at the piston rings, which decreases friction as well as fuel consumption. In addition to the engines, start-stop and regenerative braking systems, lightweight aluminum body design, LED lights, highly efficient A/C system and even economical route guidance in the navigation system contribute to an Audi TDI’s high fuel economy. Owing to this abundance of cutting-edge technology, the 2.0L TDI in the A4 puts out 136 HP while offering its owners a 51.1 mpgUS combined rating on the NEDC. The 1.6L TDI, which will be included in the A3 model lineup in 2010, delivers 105 HP yet is rated at an 61.9 mpgUS combined on the NEDC with a correspondingly low 99 g/km CO2 output. During the recent Audi Efficiency Challenge A to B, a tour of Europe covering more than 2,599 miles, the two A3 1.6L TDI’s averaged 71.3 mpgUS while the larger A4 2.0L TDI averaged 53.5 mpgUS. Such endurance tests are a tradition at Audi. The first Audi 100 TDI models traversed the European continent achieving sensationally low fuel consumption as well as long distances traveled between refills. The future - Audi clean diesel 20 years after the market launch of the TDI, Audi is continuing to expand its lead and is positioning itself for the future. Its innovative clean diesel technology converts NOx into harmless nitrogen and water. The 3.0L TDI clean diesel engine meets the strictest exhaust emission limits in the United States as well as the Euro 6 limits announced for 2014. It is today propelling both the Q7 and the A4. In the medium term, Audi is relying on second-generation biofuels including sunfuel. These fuels use the residues of energy plants – not merely their fruits, as is the case in current versions of biodiesel. During combustion, they emit as much carbon dioxide as they have consumed from the atmosphere during their growth. Independently of this, Audi will continue to further reduce fuel consumption of its fleet of vehicles – with a target of 20 percent below its 2007 level by 2012. The potential inherent in the TDI is far from exhausted. In the past 20 years, Audi has written a tremendous success story with this engine concept and will continue to do so well into the next decade.