Introductory study of variable valve actuation for pneumatic hybridization

Sasa Trajkovic*, Per Tunestål, Bengt Johansson, Urban Carlson, Anders Höglund

*Corresponding author for this work

Research output: Contribution to conferencePaperpeer-review

25 Scopus citations


Urban traffic involves frequent acceleration and deceleration. During deceleration, the energy previously used to accelerate the vehicle is mainly wasted on heat generated by the friction brakes. If this energy that is wasted in traditional IC engines could be saved, the fuel economy would improve. One solution to this is a pneumatic hybrid using variable valve timing to compress air during deceleration and expand air during acceleration. The compressed air can also be utilized to supercharge the engine in order to get higher load in the first few cycles when accelerating. A Scania D12 single-cylinder diesel engine has been converted for pneumatic hybrid operation and tested in a laboratory setup. Pneumatic valve actuators have been used to make the pneumatic hybrid possible. The actuators have been mounted on top of the cylinder head of the engine. A pressure tank has been connected to one of the inlet ports and one of the inlet valves has been modified to work as a tank valve. The goal has been to test and evaluate 2 different modes - compression mode (CM) where air is stored in an air tank during deceleration and air-motor mode (AM) where the previously stored pressurized air is used for accelerating the vehicle. This paper also includes an optimization of the CM.

Original languageEnglish (US)
StatePublished - Dec 1 2007
Event2007 World Congress - Detroit, MI, United States
Duration: Apr 16 2007Apr 19 2007


Other2007 World Congress
Country/TerritoryUnited States
CityDetroit, MI

ASJC Scopus subject areas

  • Automotive Engineering
  • Safety, Risk, Reliability and Quality
  • Pollution
  • Industrial and Manufacturing Engineering


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