A new hybrid system could yield fuel economy improvements as high as 10 per cent.
When the second-generation GM Hybrid System is applied to a four-cylinder common rail diesel the fuel economy improvements are achieved along with a corresponding reduction in emissions according to Maurizio Cisternino, the GM powertrain Europe advanced engineering hybrid innovation manager.
During a presentation at the US Department of Energy’s 2010 Direction in Engine Efficiency and Emissions Research Conference he spoke about an internal study that included test-bed experimental engine work and vehicle tests using an Opel/Vauxhall Corsa with a 1.3litre diesel 95hp Euro 5 engine with manual transmission. The activities looked into the optimisation of hybrid control and calibration strategies including: start/stop functionality; start/stop activation strategy; enhancement of vehicle transient performance; and drivability subjective assessment in coast and brake regeneration modes.
The testing revealed a general improvement of CO and HC emissions thanks to the decrease in engine idling time. There was also a reduction in exhaust emissions thanks to lower generation and quicker DOC light off.
Furthermore, nitrogen oxide emissions improved by 13 per cent when the EGR functionality was mated to the hybrid functionality, while electric assist also helped to reduce emissions.
Now GM will continue it’s testing in an attempt to evaluate the synergies of mild hybrid technology with a turbocharger for optimal turbo-charging; as well as lower temperature EGR; and a valve deactivation for energy recovery.
