How Important Are Heat Shields For Automobile Exhaust System ?

There are  highest quality reflective heat shields on the market, they can  shield up to 90% of radiant heat. With use a 1/4" thick ceramic inner pad sandwiched between heavy duty foil and bound together with a stainless steel mesh at the edges. By binding the edges with this mesh, we create greater flexibility and a more rugged product. This heat shields withstand 1100°F continuous radiant heat and 500°F of direct contact. All are not designed for direct contact with exhaust systems, Heat shield is intended for wrapping around air boxes, electrical boxes, air conditioning components, or used as a catalytic converter and muffler heat shield.

So now if you have already Cataytic Convertors in the system , definitely the temperatures in terms of radiations can be great and there by risk of inflammation situations. if the road to vehicle gap is low , it can easily melt tar on the road More over these high temperatures in Exhaust gas after treatment systems causes Nox emissions to reduce , so the heat can be around 500 to 800 degree centrigrade . Magnesium based catalyst convertors have around 1000 to 1300 centigrade withstand capacity, Especially Nox components need these temperature to be low. So all in all these shields definitely provide the reasonable comfort of heat transfer not only to the people in the box , but definitely the protection to the components in the surrounding , of exhast systems . Engines with pilot and small injections after combustion (Called scavenging techniques) the continuous radiant heat is high and near engine there are lot of other electronics and actuators which need this heat shields. The heat shields basically fall into the category of HEAT protection systems. So protection of components surrounding a 1000 deg centrigage makes them VERY IMPORTANT. They can be of aluminium where they reflect the heat but not absorb to make the design cheap and as these are plates , they should flexible there aluminium has been quiet a good choice.

Shape and structural design can be done and found  with FEM calculations ( Radiation equations of heat distribution , stefan boltzman laws with wall thermal radiations lay a fundamental ground to design )  to identify the heat holes and then modify and optimize the use of heat shields to reduce costs and save space.

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