Progress through Turbo
A new power era in the DTM: the 2019 season rings in the fielding of modern turbo engines in the popular touring car series. Audi has developed and built a new high-efficiency power plant for this purpose – and in doing so, achieved another technological milestone in its successful turbo history in motor racing that began nearly 40 years ago.
2,000 NEW PARTS
Audi developed every single one of the total of some 2,000 assembly components of its new turbo engine from scratch. The turbocharged four-cylinder inline power plant was built according to the new Class 1 regulations coming into effect in 2019. The compact front engine is longitudinally mounted in the 2019 model generation of the Audi RS 5 DTM.
1,000 HOURS OF RIG TESTING
After some 1,000 hours of rig testing and about two and a half years of development time, the new DTM turbo engine of the brand with the four rings is ready to race. Before being installed in the racing car, every engine that will compete in the eight RS 5 DTM cars in 2019 is run through a break-in programme on the test rig for another two to three hours, a performance check and various functional tests.
In powertrain and engine development, Audi uses three types of test rigs: on the one-cylinder rig, only one cylinder of the future engine is tested. These tests are focused on the combustion process and friction performance. The full new engine is developed on the engine dyno, and on the suspension test bench the new engine, in combination with the entire drive system of the vehicle, is run as realistically as possible.
EXTRA OUTPUT OF SOME 30 HORSEPOWER
Starting in the 2019 season, the DTM will race with a ‘push-to-pass’ system for the first time. This means that every driver can push a button to boost the engine output of his racing car for five seconds, for instance in overtaking manoeuvres. Specifically, ‘push-to-pass’ boosts engine power by some 30 horsepower.
CHARGE PRESSURE OF 3.5 BAR
The turbocharger of Audi’s new DTM engine operates with a maximum absolute pressure of 3.5 bar. The underlying technical principle: by means of a turbine, driven by the engine’s exhaust gases, the intake air is compressed at a higher ratio. As a result, more of it is sent to the combustion chambers of the cylinders. This extra amount of combustible air produces extra output.
The new Class 1 regulations of the DTM are geared to maximum engine efficiency. Just like with production vehicles, the challenge is to extract the maximum from the available amount of fuel by using an internal combustion engine with a high compression ratio and very good efficiency. Accordingly, Audi developed a new high-efficiency engine for the DTM. It has to comply with the following rules: a maximum of 95 kilograms – a maximum of 100 kilograms when the ‘push-to-pass’ system is used – of fuel (RON 98) per hour may flow towards the engine.
85 KILOGRAMS TIPPING THE SCALES
Audi’s new DTM engine weighs 85 kilograms. As a result, the four-cylinder turbo unit is a lightweight engine because it tips the scales at 63 kilograms less than the naturally aspirated V8 power plant (148 kg) that was used previously.
LASTING FOR 6,000 KILOMETRES
As in the past, a DTM engine has to last for a full season – in other words 18 races in 2019. Consequently, Audi designed the engine for mileage of some 6,000 kilometres. More than 100 horsepower of additional output and the higher torque mean additional loads acting on the entire powertrain, plus: a four-cylinder engine generally generates higher vibrations than a V8 unit for example.
2 IMPORTANT ROLES
Ulrich Baretzky (Head of Engine Development) and Stefan Dreyer (Head of Powertrain Development) are the engineers at Audi who are responsible for the concept design of the new DTM engine.
For Ulrich Baretzky (64), a mechanical engineer from Straubing and successful chief developer of many Audi racing engines for more than 30 years, the new power plant marks another technological highlight:
“The new DTM engine has an extremely low specific consumption, which is now in ranges that used to be typical for diesel engines. In terms of weight and lightweight design – especially in the context of avoiding CO2 emissions – we’re pointing out a few approaches that will hopefully find their way into future road-going vehicles as well – just like in the case of our first TFSI for Le Mans and the TDI. The internal combustion engine still has a long future and complements electric mobility really well. There’s still a lot of potential for further development.”
Stefan Dreyer (45), a mechanical engineer from Stuttgart and successful in many racing projects with Audi Sport for 20 years, emphasises the positive sporting effects of this new engineering design: “We’re happy and proud to be able to start a new DTM era with the new engine. I’m convinced that we’ll be able to deliver the most spectacular touring car racing of all time for the fans and customers.”
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