Plastic Fantastic

The high cost of oil is hitting motorists hard in the pocket. But carmakers are looking at fuel economy from a very different perspective – regulators within both Europe and the US are tabling tough new laws designed to curb CO2 emissions.

The EC has drafted legislation aimed at reducing average fleet CO2 emissions from new passenger cars from today’s level of 160g/km to 130g/km by 2012, a reduction of 19%. In the US, regulators are looking for a 4.5% improvement in Corporate Average Fuel Efficiency (CAFE) performance each year until 2015, when it wants to see passenger cars averaging 35.7mpg (15.2km/l).

Achieving these targets will require a whole raft of new technologies, but one weapon in the armoury will be a renewed focus on weight reduction. And plastics will play a key part.

One of the key challenges will be to reverse the trend for cars to grow with each generation. Jean-Claude Steinmetz, vice president for the automotive and transport market at Rhodia points out that average vehicle weight increased over the period from 1995-2005 period from 1,100kg to 1,300kg.

More specifically, he says the first Volkswagen Golf weighed 750kg. Today’s Golf weighs 1,400kg. “36% of emissions are due to weight. If 20% weight can be saved, it means 10-12g/km less CO2 emission,” he says.

Steinmetz believes a greater use of plastics could still cut around 35kg from vehicle exterior parts, 22kg from the engine compartment, and 63kg off the structure of a vehicle.

Expanded PP foam producer JSP also emphasises the emissions saving potential of plastics. It claims that the use of its foams in seating systems, for instance, can reduce weight by up to 35% – or 10kg per car.

“A 10 kg weight saving in a car that sells over 100,000 units annually and has a kerb weight of 1,200 kg is the equivalent of reducing the environmental impact of its production by over 800 cars a year,” says JSP Europe chief operating officer Paul Compton. “On an average car that’s a reduction of over 20,000 tonnes of CO2 annually.”

A review of sustainability carried out by Johnson Controls Interiors also underlines the critical role of weight reduction. It calculates that 77% of green house gases (GHG) occur during the usage phase of a vehicle, with fuel extraction, processing and distribution accounting for 11%, manufacturing 9.5%, resource extraction and transportation 3.4%, and end-of-life disposal 0.13%.

Faurecia’s CEO for automotive parts Yann Delabriere told EPN sister magazine Automotive News Europe that weight reduction is now a top priority. “We have been discussing weight for years, but not with the same cost consciousness,” he says.

Faurecia’s product portfolio – seating, cockpits, bumpers and exhaust systems – accounts for around 16% of the weight of a typical vehicle, so scope for it to influence vehicle weight is huge. “If we account for 16% of the weight of a car and the car weighs 1.2 tonnes, then our products represent about 190kg. If we reduce this by up to 20%, that means about 38kg,” he says.

Plastics headlamps and body panels have been a key contributor to weight reduction over the past decade– while also improving design flexibility. That combination of benefits is now ready to transfer to the vehicle’s glazing.

Sabic Innovative Plastics European automotive market director Derek Buckmaster estimates that replacing the side and rear glass on all the passenger vehicles on the road in Europe today with PC alternatives could reduce fuel consumption by around 2,100m litres a year and CO2 emissions by around 5.2m tonnes.

And US envirommental strategy group GreenOrder calculated that the Qarmaq concept SUV developed by Sabic IP together with Hyundai to showcase the potential of PC glazing resulted in a 60kg weight saving.

It is unlikely that Renault chose PC for the rear quarterlights and screen on the limited edition road-going version of its high performance Megane F1 Team R26 car to reduce emissions, but the weight saving it achieved – 5.7kg per car – shows what can be realised through the use of polymers.