Two separate regulation changes are challenging commercial vehicle manufacturers; emissions standards are driving exhaust temperatures up while safety legislation is demanding a reduction in temperatures.
As a result, thermal management specialist, Zircotec, is developing new solutions, including ceramic coatings, for several manufacturers.
deal with a uniquely difficult combination of exhaust system challenges
Internal exhaust temperatures are expected to rise from 500°C to 700°C, while the maximum external surface temperature, currently as high as 480°C, could be mandated down to just 70°C.
Internal exhaust temperatures are being increased to improve emissions performance ahead of tighter future standards, while external temperatures must be reduced to meet safety legislation and packaging needs.
“Heat management is easy if the only requirement is to reduce heat loss and you have enough space to install sufficient insulation; however, that just isn’t the case in most applications,” said Zircotec Group Sales Director, Graeme Barette.
“Conventional insulation would typically need to be up to 70mm thick to achieve the thermal barrier performance required. There is not room for such a thickness even with commercial vehicles, without re-routing the exhaust and introducing knock-on effects that compromise other systems and overall packaging, to say nothing of the cost involved.”
Zircotec is partnering with a leading vehicle manufacturer and exhaust component suppliers to investigate ways to integrate ThermoHold, the company’s ceramic based heat shield coating, within the exhaust manifold.
Prototypes have been produced by the manifold supplier at their facilities and early trials and the associated test results have been “very promising,” according to Zircotec.
Another key industry focus is on the thermal management of after-treatment systems to significantly improve conversion efficiency.
By using thermal barrier technology inside and around the DPF (Diesel Particulate Filter) and catalyst, the internal gas temperature can be increased, ensuring that heat is delivered and focussed where it is most needed, while simultaneously reducing external heat transmission. Zircotec is working with another customer on the insulation of a modular catalyst unit.
Zircotec, a specialist heat management company, was formally part of the UK Atomic Energy Authority, and is based near Oxford.
Its expertise in thermal barrier technologies was originally developed for the nuclear industry and many of its scientists and engineers have remained with Zircotec since its nuclear origins.
The company’s products include: plasma-sprayed thermal barrier coatings; exhaust system coatings; inlet manifold coatings; heat shield materials; wear resistant, anti-corrosion and aesthetic coatings; ceramic coatings and metal coatings for carbon composites and high-temperature plastics; and specialist plasma-sprayed ceramic products.
