# Thermal dynamics - Metals on Engine Components

1. May 30, 2012

### ZCHondaCRX91

I have some car engine related questions, but basically just physics.

-Do different specific heat capacities have anything to do with how certain materials resist heat? I know that on some engine compartments there is gold wrapping because it resists heat best, but it has a low specific heat capacity. I know the higher the heat capacity the more energy is needed to increase the temperature.

-What are the best metals or materials that resist heat? For example in an engine compartment where the underhood temperature fairly warm, what materials for the intake components would resist heat best so the IAT won't increase too much?

-Are there plastics or rubbers that resist heat more than metals?

-Is that the correct way to say it, "resists heat?" If you have two containers filled with water, with the same mass and thickness, but different materials, and are placed in a oven for the same amount of time. Then when you measure the temperature in both containers and in one the water is a lower temperature than the other, would you say that material resists heat better?

I want to learn, but can't find any clear answers for these specific questions. Any help is very much appreciated. Thanks.

2. May 31, 2012

### ZCHondaCRX91

250 views, no answers? If you know of something I should read please let me know. Thanks.

3. May 31, 2012

### 256bits

The parts of your car, such as under the hood, have a shiny material to reflect the heat and basically nothing to do with heat capacity. Between the shiny and hood is some insulation to further resist the heat as you say to keep the hood a little bit cooler.

A material has heat capacity and thermal resistance. You could say that insulation has a higher thermal resistance.

A container which has a higher thermal resistance will allow the temperature of the water in your oven example to rise less quickly than the other container, if you would plot temperature of the water versus time. Eventually though after a certain long enough period of time the water in both containers would be the same all other things considered equal.

4. May 31, 2012

### ZCHondaCRX91

Thank you, that makes sense.

5. May 31, 2012

### pa5tabear

Have you heard of thermal diffusivity?

It's a dimensionless quantity (no units) which combines density, heat capacity, and thermal conductivity. I can't link yet, but the wikipedia page explains more.

A material with a low thermal diffusivity would "resist heat".

6. May 31, 2012

### ZCHondaCRX91

No, didn't know that. Will do some reading on that. Thank you.