Fuel consumption and emission reduction by using a CVT in series with conventional multi-speed transmission

Fuel economy is a growing concern for both manufacturers within the automotive sector and consumers. Increasing government legislation is driving towards greener vehicles with reduced CO2 and NOx emissions and greater fuel economy, especially within urban environments. Manufacturers use new technologies in their powertrain systems to tackle these problems. This paper simulates and evaluates the performance of using a half toroidal CVT in series with a conventional multi-speed transmission, by analysing different shifting strategies to optimise fuel consumption and NOx emissions over the NEDC using this novel approach. The results show an 8.83% increase in fuel economy and up to an 11.34% reduction in NOx emissions is possible using this arrangement. The introduction of CVT adds a further 1.18% increase in fuel economy and 3.59% decrease in NOx emissions. The paper concludes that this novel arrangement should be considered by automotive manufacturers as a solution for improvements to powertrain technology.