Audi engineers have intensively further developed the new 3.0 TDI diesel engine for the European market. In the new Audi A5 and Q5 models, the V6 diesel outputs 210 kW (286 hp) as well as 620 N·m (457lb-ft) of torque (this engine version is not yet for sale. Since it still lacks an overall type approval, it is not subject to Directive 1999/94/EC), the latter from 1,500 to 3,000 revolutions per minute.
The six-cylinder engine has a displacement of 2,967 cm3 (bore x stroke 83.0 x 91.4 millimeters (3.3 x 3.6 in)). As with all V engines from Audi, its two banks lie at a 90-degree angle from one another. Inside the cylinder crankcase, made of high-strength cast iron with vermicular graphite, a balancer shaft rotates in order to reduce engine vibrations and to improve acoustics. The ignition pressure reaches the 200 bar mark over wide areas of the characteristic map.
The strict lightweight concept from Audi used for the crankshaft, the cylinder heads and the cylinder crankcase increases efficiency. Another aspect which plays a role here is reduced friction at the piston rings and pins thanks to the special cylinder wall coating. The use of a performance-regulated oil pump is also economically beneficial.
|Audi recalls 24,000 cars in Europe with Euro 5 TDI engines|
|Audi has detected anomalies in the NOx emissions in certain driving conditions of approximately 24,000 cars of the A7 and A8 model series with TDI diesel engines certified to EU5.|
|For several months now, Audi has been systematically investigating the emissions of a large number of engine-transmission combinations in certain driving conditions. The latest analyses of A7 and A8 automobiles of model years 2010 through 2013 with V6 and V8 engines certified according to the EU5 emission standard have revealed that in certain situations, NOx emissions are between 20 and 100 percent above the limit.|
|In some situations, engine speed is unfavorably influenced by the transmission software, which can have a negative impact on the engine’s emissions. Audi has agreed with Germany’s Federal Motor Transport Authority that it will actively approach the relevant customers and recall the affected cars. 14,000 of those 24,000 cars are registered in Germany. The recall is likely to start in July 2017. As only a software update will be installed, the time required for the work on the cars will be about 30 minutes.|
The thermal management system segregates the circuits of the cylinder crankcase and cylinder heads from one another and supplies each with coolant after a cold start so as to bring the engine oil quickly up to its operating temperature. The cylinder heads have two-part water jackets for needs-based cooling. The oil cooler is integrated in the coolant flow of cylinder heads as needed.
The common-rail system generates up to 2,000 bar of injection pressure. The piezo injectors with their eight-hole nozzles can perform up to nine injections per work cycle.
To optimize the air flow and the fuel mixture preparation, the intake ports (one each for swirl and the other for charging) and the exhaust ports have been modified relative to the predecessor engine. Both ports have lower flow resistance. The engine thereby acquires more spontaneous response characteristics and an even more homogeneous buildup of power.
The 3.0 TDI turbocharger operates with 2.3 bar relative boost pressure. The variable turbine geometry (VTG) is designed for low-loss flow. The low-pressure exhaust gas recirculation (EGR) removes the exhaust gas only downstream from the particulate filter and sends it through a radiator, for driving the turbocharger with the full exhaust-gas mass flow especially at medium and high loads.
The two emission control components are positioned very close to the engine. The first component is a large NOC oxidation catalytic converter (NOx oxidation catalyst). It stores nitrogen oxides until it is full.
It is cleaned by enriching the fuel-air mixture in the engine. To minimize the related extra fuel consumption, the NOC kicks in especially at low exhaust temperatures. Once the operating temperature is reached, the second module of the system—the SCR-coated diesel particulate filter—takes care of NOx conversion during intercity and highway driving (i.e. in the moderate rpm range).
The further developed 3.0 TDI is prepared for mild hybridization, as first introduced in mass production by Audi in 2017 for the A8. (Earlier post.) The 48-volt vehicle electrical system, which here powers a belt alternator starter (BAS), can also provide the energy for an electric powered compressor (EPC). It supports the turbocharger when starting off and accelerating from low engine speeds, with the benefits of high spontaneity and elasticity for customers.