HOUSTON (ICIS)--Automobiles for the 2012 model year exceeded the emission standards set by the US Environmental Protection Agency (EPA), according to a report released on Friday, but automakers will need to adopt new materials to continue to meet the yearly reductions in the standards.
The emission standard under the Corporate Average Fuel Economy (CAFE) programme for 2012 light-duty vehicles was 296 g/mile (184 g/km). With credit transfers across fleets and credits for air conditioning improvements and flex fuel vehicles, overall performance for 2012 vehicles was 286 g/mile, 9.8 g/mile lower than the standard, according to the report.
The real-world emission rate was 376 g/mile for 2012 vehicles, a 22 g/mile decrease from 2011 vehicles. Average fuel economy was 23.6 miles/gal (10.0 km/litre), 1.2 miles/gal higher than 2011 vehicles, according to the report.
To meet the 2012 standards, automakers incorporated engine and transmission technologies, including gasoline direct injection, variable valve timing and continuously variable transmissions, the report said.
Vehicle weight, one of the most important parameters determining fuel economy, has been nearly flat since 2004. Weight declined to an average 3,977 lb (1,803 kg) for 2012 vehicles, a drop of only 150 lb from 2011 vehicles. Preliminary data suggest average weight could rise for 2013 vehicles, the report said.
The emission standard in the CAFE programme for 2013 vehicles is set for 286 g/mile and continues to drop through 2025 to 163 g/mile, according to EPA figures.
Automakers will have to consider incorporating new materials to reduce vehicle weight to meet future CAFE standards – 2025 standards are 44% lower than those in 2012.
Already aluminium content of vehicles has been increasing at about 5% a year for the past decade, according to a 2013 analyst report by Barclay's. Ford introduced an aluminium 2015 F-150 pickup truck, which is 700 lb lighter than a steel version would be.
High performance plastics, resins and foams can also replace steel and other high-weight components of vehicles. For example, Dow Chemical developed structural adhesives that can replace welds and rivets, further reducing the weight of a vehicle.
The American Chemistry Council (ACC) earlier this month released a roadmap to help automakers collaborate with plastics and polymer composite suppliers on lighter vehicles.
Tyres have become more fuel efficient, with a move away from standard tyres made of emulsion styrene butadiene rubber (SBR) to high-performance tyres made with solution SBR. New cars are often equipped with such tyres, and several tyre manufacturers offer them in the US as replacement tyres.
With some vehicle models already taking advantage of new materials and technologies, the EPA estimates 28% of 2013 vehicles could meet the 2016 CAFE standard if all incorporate air conditioning improvements. The bulk of that percentage is non-hybrid gasoline vehicles, although diesel, hybrids and electric vehicles are also represented, according to the EPA.
About 5% of 2013 vehicles could meet the 2025 CAFE standards, all of which are hybrids or electric vehicles, the EPA said.