Packaging heat-sensitive components in an underhood environment can be a challenge for design engineers. Specialist coating company Zircotec has just conducted what it terms “independent testing by one of the U.K.’s leading test and development centers” to confirm that the use of advanced flame-sprayed ceramic coatings can reduce heat transfer by up to 26.7%. This led to a surface temperature reduction at the exhaust manifold of up to 136ºC (245ºF), according to the company.
Flame-sprayed ceramic coatings were originally developed by the nuclear energy industry and are used by Formula One and other race teams. Now, Zircotec is supplying several OEMs, including Koenigsegg.
“We are also developing applications for improving catalyst light-off times and the performance of diesel particulate filters, which require exhaust gas temperatures to remain high,” said the supplier’s Technical Director, Andy McCabe. “The independent testing program was instigated to demonstrate the effectiveness of the coating on a V8 gasoline engine fitted with two sets of manifolds; one in standard condition, the other with a zirconia-based coating.”
The manifolds were encapsulated to simulate underhood airflow conditions, and testing was conducted on an engine dynamometer, simulating various driving conditions and road speeds.
“We wanted to present trusted, independent data, and the results demonstrate how effective the Zircotec solution is in these environments. The results clearly demonstrate that the Zircotec-coated exhaust manifold transmits significantly less heat to its surroundings than the uncoated standard part, reducing heat transfer at all the different loads and simulated road speeds of 35 mph and 70 mph,” stated McCabe. “Significantly, for harsher applications, the greatest gains were achieved when the loads and speeds were at their highest.”
In addition to the thermal barrier properties, the coating is more durable than traditional wrap, is easily packaged, and provides a fit-and-forget solution for a variety of vehicles, added McCabe.
The Zircotec process can coat most metals, and a recently developed innovation also allows carbon-fiber composites to be coated.