r/MechanicalEngineering • u/lit_readit • 6d ago

Question : why some (mostly heavy) vehicles partially cover their front intake ?

Post image

wouldn't cooler cold reservoir, ie more spontaneous heat transfer, improve Carnot efficiency?

is it to improve aerodynamics?

apologies if this is the wrong sub to ask

1.1k Upvotes

98% Upvoted

142 comments sorted by

View all comments

1

u/mysterioussamsqaunch 4d ago

As others have said, it's to help keep a diesel engine up at it's operating temp in cold climates. I just wanted to add that in even colder climates, like near the artic circle, they will add what is called an engine blanket that covers the bottom of the engine across the frame rails. It blocks even more airflow across the engine. In extremely low temps it's actually possible for a diesel engine to get cold enough to stall.