ABSTRACT
Engine downsizing has been shown as an effective means to reduce the vehicle’s fuel consumption but the full potential of engine downsizing is limited by the knocking combustion at boosted operations and the presence of pumping loss at part load conditions. In this work, an electro-mechanical valvetrain system named iVT (intelligent Valve Technology) by Camcon was used to investigate how the independently controlled variable valve timing and duration can be applied to minimise the knocking combustion by altering the effective compression ratio (ECR) at high load via Early Intake Valve Closure (EIVC) or Late Intake Valve Closure (LIVC), as well as reducing the pumping loss at part load. In particular, the effect of different valve lifts with fixed valve timings and constant duration was studied on the pumping loss, combustion process and emissions. The results show that fuel consumption was reduced up to 2.5% using iVT system compared to the baseline valve profile at 9bar net IMEP.
