The plastics industry is looking to expand its real estate under the car hood, trying to convince North American automakers to use thermoplastics in valve covers in place of the existing metal components.
A little more than half of the cars made in Western Europe use thermoplastics for the covers, but in North America metal is the material of choice.
Convincing engineers here to make a switch may not be easy or sudden, but the change is beginning to take hold.
``I think it will take the same route the intake manifold did in that [the plastic manifold] was a long time in coming, but now it is accepted everywhere,'' said Wilfred Lehr, managing director of Mann+Hummel GmbH's automotive original equipment division and a member of the Mann+Hummel board.
The covers are known by a variety of names depending on the type of engine involved - rocker covers, cam covers and cylinder head covers. All involve the same location on the engine, covering the top of the cylinder head to keep oil from spurting into the rest of the engine compartment.
Mann+Hummel, which makes the covers in Europe, estimates 51 percent of them are thermoplastics there. The typical plastics variety, made of glass and mineral-filled nylon, has 13 percent of the global market.
In the United States, however, thermoplastics do not even rank a full percentage point in usage, although thermoset plastics claim 37 percent of covers.
The North American thermoplastics usage number is expected to climb to 4 percent within two years. DaimlerChrysler AG is backing the first high-volume use of thermoplastics for valve covers with its decision to use DuPont's Minlon reinforced nylon on six-cylinder versions of its 2004 Chrysler Town & Country, Caravan and Grand Caravan minivans.
``The momentum is coming into North America,'' said Rhodia SA's Jean-Claude Steinmetz. Steinmetz, the executive overseeing Rhodia's automotive industry programs, was interviewed at the Society of Automotive Engineers 2004 World Congress in Detroit.
``You can really see how these are going to fit in,'' he said.
The selling point for the covers hinges on molders' ability to integrate features that metal systems cannot.
``Engineers want to see a one-for-one comparison, but then you lose some of the benefits of plastics,'' said Claude Mathieu, president and chief executive officer of Mann+Hummel USA Inc., the Portage, Mich.-based North American unit of the Ludwigsburg, Germany-based M+H.
The covers can come complete with integrated crankcase ventilation system as well as clips and connectors for the multiple hoses and wires within the engine compartment. The design can offer up acoustic or aesthetic performance as well.
Mann+Hummel also has looked at ways to add an air cleaner to the system.
Diesel engines may be able to combine the valve covers and the intake manifold in one complete thermoplastic system.
The further the integration goes, the more Lyon, France-based Rhodia expects suppliers will demand from their material. The company has been positioning its Technyl Star polyamide for use with under-the-hood component makers that need to get more out of the plastics, while also improving processing numbers.
``We're in the period where there is more pressure on the systems and the suppliers are looking to optimize those systems, and they can't mold it any further with plain old polyamide,'' Steinmetz said.
Any major boost in thermoplastics use on North American engine programs may be a few years away, though. Mann+Hummel is bidding on contracts now for production slated for 2007-08, according to Rick Dishaw, director of sales and business development for Mann+Hummel USA.
