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Challenges and Solutions for modern Gasoline Engine Applications
Both the future test cycles and more fuel-efficient transmission and electrification concepts are shifting the ICE operation towards higher engine loads. Whereas in the past, FE measures with Gasoline Engines were mainly concentrated on the reduction of throttle losses, in future the extension of the sweet spot area becomes decisive. Consequently, a complete re-evaluation of existing technologies as well as new technology approaches are required also in view of the simultaneously aggravated limits for pollutant emissions.
Highly differentiated market demands will result in an increasing differentiation of specific power between “Top Performance / Image Concepts” heading up to 200 kW /l and “Fuel Economy Concepts” targeting a minimum BSFC of 200 g/kWh. In spite quite different boundaries, various base elements like knock resistant combustion systems, highly efficient charging devices, optimized friction, etc. can be utilized both for highest power and for best efficiency.
Based on fixed valve lift and compression ratio, the engines can offer either high performance or high efficiency. Miller / Atkinson Cycle not only provides an extended expansion, but also a very cost efficient variation of effective displacement. This enables a new philosophy for engine families – power differentiation less by geometric displacement and boost pressure but more by the degree of “Millerization” and the geometric compression ratio.
This also enhances the trend from “Maximum Downsizing” towards “Rightsizing”. Extreme high specific power levels will be just applied to enlarge the power range within existing engine families and packaging constraints but less for mainstream fuel economy improvement. High efficiency engines will concentrate not only on load shift by downsizing but will stronger balance geometric displacement and minimum BSFC.
Most decisive for cost effective FE solutions is the comprehensive integration of future Gasoline Engines into the complete powertrain allocating the variability required to comply with future fuel economy legislation in the respectively most cost effective way: from a “Fully Flexible Combustion Engine” towards a “Fully Flexible Powertrain”.
Highly differentiated market demands will result in an increasing differentiation of specific power between “Top Performance / Image Concepts” heading up to 200 kW /l and “Fuel Economy Concepts” targeting a minimum BSFC of 200 g/kWh. In spite quite different boundaries, various base elements like knock resistant combustion systems, highly efficient charging devices, optimized friction, etc. can be utilized both for highest power and for best efficiency.
Based on fixed valve lift and compression ratio, the engines can offer either high performance or high efficiency. Miller / Atkinson Cycle not only provides an extended expansion, but also a very cost efficient variation of effective displacement. This enables a new philosophy for engine families – power differentiation less by geometric displacement and boost pressure but more by the degree of “Millerization” and the geometric compression ratio.
This also enhances the trend from “Maximum Downsizing” towards “Rightsizing”. Extreme high specific power levels will be just applied to enlarge the power range within existing engine families and packaging constraints but less for mainstream fuel economy improvement. High efficiency engines will concentrate not only on load shift by downsizing but will stronger balance geometric displacement and minimum BSFC.
Most decisive for cost effective FE solutions is the comprehensive integration of future Gasoline Engines into the complete powertrain allocating the variability required to comply with future fuel economy legislation in the respectively most cost effective way: from a “Fully Flexible Combustion Engine” towards a “Fully Flexible Powertrain”.
Tematyka artykułu: Pomiary i kontrola emisji
Autor: Hubert Friedl
Współautor(zy): Dr. G. Fraidl, Dr. P. Kapus
