Audi Sets New Lap Record For Cars With Diesel Engines
Audi has set a new lap record for diesel-powered cars around the German Sachsenring race track. The vehicle used was the 2014 Audi RS 5 TDI competition concept, which managed to complete a run around the 3.6 km (2.2-mile) course in 1 minute 35.35 seconds, besting the previous record by 1.87 seconds. Powering the car was an innovative twin-turbo six-cylinder that gets an additional boost from an electrically driven compressor.
Behind the wheel was professional racer Nicki Thiim, who drove the Audi on its record-breaking run as part of Sachsenring Record Day, an event organized by Michelin and the German magazine Auto Bild Sportscars. The achievement echoes similar success attained earlier in the spring, when the German publication Sport Auto brought the RS 5 concept to Hockenheim and posted the quickest lap in the mag’s history for a diesel-powered car.
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Why it matters
Originally debuting last summer in conjunction with the 25th anniversary of the TDI engine, the RS 5 TDI concept has been developed extensively for the race track. It currently uses a 3.0-liter V-6 boosted by twin turbochargers and an electrically driven compressor to produce 435 horsepower and a heady 590 pound-feet of torque. This muscle enables a sprint to 60 mph in four seconds flat, while 200 km/h (124.3 mph) is achieved in less than 16 seconds.
The RS 5 TDI concept has been developed extensively for the race track.
Other innovations in the vehicle include the use of various exotic lightweight materials, such as carbon-fiber-reinforced polymer (CFRP) in the hood, aluminum doors, and an exhaust composed mostly of titanium. In the cockpit, more CFRP is used in the bucket seats, while the rear bench was eliminated. Thinner glass and a polymer material are used for the windows. The result is a vehicle that weighs an impressive 241 kg (531.3 pounds) less than the standard road-going model.
Of course, the main focus of the project is the diesel engine and its electric turbine. While the two snails do their work the old-fashioned way, drawing from the exhaust gases to compress the intake charge, the electric turbine requires no spool-up time, yielding better low-end response and helping the turbos get down to business. The compressor utilizes a small electric motor running at 7 kW to spin a turbine to 72,000 rpm within a mere 250 milliseconds, offering a good deal of boost as soon as the hammer is dropped.
By comparison, old-school high-output turbocharged engines have turbo lag, making throttle modulation more of an on/off switch. Superchargers are an alternative form of forced induction, offering better response, but typically don’t provide the same levels of output and create parasitic loss on the drivetrain. By combining the electric compressor and two turbos, Audi gets the best of both worlds.
The compressor uses a 48-volt electrical sub-system to power it. Audi says this sub-system is a key component to its electrification strategy, as it enables “rapid transfer of large amounts of electrical energy, and so it is excellently suited for use with the electrically driven compressor.”
Audi is well known for its innovations in the realm of sporty oil-burners. The make was the first to popularize turbo-diesel engines at the 24 Hours of Le Mans, bringing its 2006 audi R10 TDI out to compete in the prestigious endurance race in 2006.
Audi is well known for its innovations in the realm of sporty oil burners.
While it wasn’t the first diesel to make an appearance at Le Mans (that honor goes to the Delettrez Diesel entered by Jean and Jacques Deleterrez in 1949, which had a 4.4-liter six-cylinder), it was the first diesel to win the event. And win it did – over and over again, taking top honors every year after its introduction until it was replaced by the R15 in 2009. It should be noted that the R10 also won its maiden race at the 2006 12 Hours of Sebring.
Over the last few years, diesels have hit the performance sector in a big way. Cars like the 2014 Porsche Panamera Diesel, 2014 Alpina D3 Bi-Turbo, and 2014-2015 Maserati Ghibli are just a few examples of sporting vehicles stuffed with diesel engines. With efficiency being a major selling point that will only become more relevant as time goes on, diesel power will undoubtedly provide several solutions for those looking to get a speed fix. Complementing this will be tech like Audi’s compressor and electrical subsystem, both of which the automaker says will enter series production soon.
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