Combustion models for the future

Audi SQ5: Fuel consumption (combined*) in l/100 km: 8.5–8.1CO₂ emissions (combined*) in g/km: 222–211
Information on fuel/power consumption and CO₂ emissions with ranges depending on the selected equipment of the vehicle.
Only consumption and emission values according to WLTP and not according to NEDC are available for the vehicle.
Audi SQ5: Fuel consumption (combined*) in l/100 km: 8.5–8.1CO₂ emissions (combined*) in g/km: 222–211
Information on fuel/power consumption and CO₂ emissions with ranges depending on the selected equipment of the vehicle.
Only consumption and emission values according to WLTP and not according to NEDC are available for the vehicle.
Audi still plans to sell around 60 to 70 percent of its vehicles with a combustion engine in 2025. This figure reflects a combination of consumer demand and statutory requirements. Audi aims to continue giving its customers a premium driving experience. At the same time, engines will need to comply with the prevailing emissions legislation and help reduce CO₂ and other emissions.
Technical advances mean lower emissions
The brand with the four rings uses sophisticated exhaust aftertreatment systems to comply with ever lower emission limits. As well as featuring internal engine measures, the latest gasoline and diesel engines meet the tough requirements by specifically focusing on efficient, technically advanced exhaust emission control systems. On TDI and TFSI engines, particulate filters complement catalytic exhaust aftertreatment.
Technologies such as twin dosing are used in exhaust aftertreatment. Over 90 percent of the nitrogen oxides from diesel engines is then converted across a wide temperature and operating range.

Thanks to this technology, in 2020 the new Audi SQ5 TDI for example already easily undercut the limit values of the “Euro 6d ISC-FCM AP” emission standard that took effect on January 1, 2021. Thanks to a new intercooling system, the engine’s emission control function is also activated more quickly.
The combustion process itself can also be optimized by increasing the injection pressure, for instance. Efficient cooling techniques maintain a constantly high performance combined with high fuel economy and low emissions. New materials such as pistons made from forged steel instead of aluminum reduce thermal losses without bringing any weight disadvantages.



Mild hybrid system: lower CO₂ and fuel consumption but superior driving pleasure
As well as its measures to improve the combustion process and exhaust aftertreatment, Audi is systematically rolling out the mild hybrid system for its combustion engines. This form of partial electrification not only cuts CO₂ emissions and fuel consumption by up to 0.7 liters per 100 kilometers. In combination with an electric powered compressor it also makes the power unit more responsive. The plan is for every Audi combustion engine – entry-level models excepted – to be partially electrified by 2025, either as a plug-in hybrid or with a mild hybrid system.
Platform principle and common parts approach for reduced complexity
With emissions legislation becoming increasingly rigorous, the cost of reducing emissions will also rise in the coming years. Audi can compensate for this trend in three ways.
First, the Company is giving a sharper focus to its range of combustion engines without creating gaps in the offering. For example, over recent years the Company has significantly scaled back the number of engine and transmission versions.
Audi is also championing the platform principle: A basic engine can be modified using additional components or identical components made from materials that exhibit varying degrees of robustness, to cover a range of performance categories. That avoids the need to develop completely new engine versions every time.
In addition, as many common parts as possible are used within each performance category and across the various evolutionary stages of an engine family. In the case of Audi’s top-selling engine, the EA888 inline gasoline version, the developers have achieved a common parts content of 70 to 80 percent across the three performance categories. Over the coming years (up until 2025) this engine will be installed some 13 million times in various VW Group models. The scope for leveraging cost savings with common parts is correspondingly high.