The branch of physical science that deals with heat.
Relations between heat and other forms of energy (such as mechanical, electrical, or chemical energy), and the relationships between all forms of energy.
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Questions tagged [thermodynamics]
7 questions
23
votes
3 answers
Why does a gas engines torque and horsepower curve always meet at 5252 RPM?
I'm watching a TV show called Tech Garage and they just made the claim that an engines torque and horsepower curves always meet at 5252 RPM. Assuming this is true, why does this happen? Is it something designed into engines, or is it just how the…
cdunn
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votes
4 answers
What exactly is a catalytic converter and why does it need to operate within a certain range?
I heard here that a catalytic converter needs to operate within a certain "chemical range" otherwise it will generate unnecessary heat.
What exactly is a catalytic converter?
How does it work?
What is their purpose on a car?
Are they necessary…
Max Goodridge
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10
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9 answers
Why is it that when supercharging, it's preferred to compress the input, rather than pull a vacuum on the exhaust?
It's a strange dilemma, but if the power of an engine is determined by the difference in pressure between the combustion chamber and the exhaust, it should follow that turbocharging should be equally effective pumping air out the exhaust, than in…
tuskiomi
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7
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1 answer
Why no exhaust gas turbine generator in hybrid vehicles?
I found something interesting on Wikipedia today: a hybrid turbocharger. This is a device that charges a battery with an exhaust gas turbine, and at the same time operates an air compressor using the battery to pack more air into the engine. As a…
juhist
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4
votes
1 answer
Thermocouple vs Thermostat
Why don't modern engines use a thermocouple (electronic temperature sensor) instead of a (wax element) thermostat?
voices
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2
votes
1 answer
Tire Pressure Monitors during very cold temperatures
As outside temperature decreases by 10 degrees Fahrenheit, tire pressure decreases 1 psi. However, in very cold temperatures of -10 degrees Fahrenheit, the vehicle TPMS indicates low pressure but the tire pressure is at the normal pressure. Has…
Paul
1
vote
2 answers
Cast iron vs aluminium engine blocks
From what I can tell by reading, aluminium engine blocks are more thermally efficient than cast iron blocks - but it also seems that aluminium is more thermally conductive than iron.
That seems counterintuitive to me. How come an engine that…
Erik
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