For years automakers have been directing their energy towards delivering smaller displacement powerplants, but new research is now suggesting this is actually increasing the CO2 and NOx levels.
It appears automakers such as Renault, Volkswagen and others are starting to again scale up their engines in order to lower the environmental impact after years of downsizing their engines in hopes of reducing emissions. The larger engine displacement movement has come to light in the wake of Volkswagen’s Dieselgate scandal, which also cast a shadow on the unrealistic testing procedures. These were done at impractically moderate temperatures and speeds and didn’t show that in real-world settings the smaller displacement engines, both gasoline and diesel, actually polluted more than some larger displacement versions.
“The techniques we’ve used to reduce engine capacities will no longer allow us to meet emissions standards,” said head of powertrain at Nissan-Renault, Alain Raposo, on the sidelines of the Paris Motor Show. “We’re reaching the limits of downsizing.” For example, Volkswagen has delivered a 1.6-liter replacement for its 1.4-liter three-cylinder diesel in cars like the Polo, while Renault has decided to increase by 10 percent the 1.6-liter R9M diesel engine, which was introduced new in 2011.