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AVL Aggressively Downsized Diesel Engine

AVL made a concept for an even more extreme downsizing approach for the next generation of powertrains by further reducing the engine size to 1.0L using a 3 cylinder concept with a specific power rating of 80 kW/L

AVL Solution

Significant CO2 reduction in NEDC
  • Potential of 7% reduction depending on vehicle weight and DeNOx stategy

Same performance & driveability as K9K 1.5L
  • Performance targets fulfilled with 190 bar PFP design limit
  • Base engine structure capable for the high mechanical and thermal loads

EU 6 Emissions compliance
  • Euro 6 emissions feasible with NOx aftertreatment

Comparable NVH behaviour to K9K 1.5L
  • No balancer shaft required in combination with AVL mounting concept
  • NVH remains a challenge for the 3 cylinder engine in larger cars in view of the torque fluctuations


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AVL Approach

AVL and Renault worked closely together to define a suitable diesel hybrid powertrain concept for EU6 emission limits. The consequences for the base engine design of such an aggressive downsizing approach were established by means of a design study supported by simulation. Key criteria for such a powertrain are to satisfy customer expectations for performance and driveability, as well as to keep the NVH behavior of the selected 3-cylinder engine configuration close to that of the traditional 4-cylinder engine reference base.
The structural concept of this high power engine is based on a peak firing pressure limit of 190 bar. 2- and 4-valve per cylinder concepts are evaluated with regard to their effects on performance, emissions, fuel consumption and cost. The combustion and EGR-system is defined with respect to EU6 emission compliance, taking into consideration DPF and NOx after treatment technologies.


  • Significant CO2 reduction in NEDC
  • Same performance and driveability as K9K 1.5L engine
  • EU 6 Emissions compliance
  • Comparable NVH behavior to K9K 1.5L engine

Boundary conditions

  • Potential for electrification for start-stop, recuperation and boosting
  • Consideration of MT and DCT
  • Beneficial technology cost – ratio
  • Production commonality with existing K9K engine


International Viennese Engine Symposium 2010

The CO2 Challenge: Aggressive Downsizing for HSDI Diesel – Engine Concept Definition

Author(s) AVL: Dr. Helfried Sorger, Michael Howlett, Wolfgang Schnider, Norbert
Ausserhoffer, Dr. Peter Bartsch, Michael Weißbäck