AC compressor and throttle logic
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More Turbo
Joined: Mar 2022
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AC compressor and throttle logic
On a diesel, take my 2021 6.7 for example, with the AC on does the compressor disengage when flooring the throttle? How about part throttle over a certain RPM? This has me curious as to if the compressor run regardless of throttle position or RPM vs a wear perspective on the compressor. Merging for a quick blast to 3k rpms vs pulling heavy and running 2500-3,000rpm for 40 minutes straight. Should I switch off the AC when getting on it?
Cargo Master
Joined: Apr 2021
Posts: 2,017
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From: Texas
mine will turn off recirc if i am at around 65 and mash the go pedal firmly but not to the floor to pass, on a two lane road. it will be at 85 pretty darn quick to go around.
not sure what the logarithm is to drive ac compressor off momentarily but i imagine like most vehicles its depends on many variables as in foot speed to wot or 3/4 , and road speed plus engine power demanded
my wifes edge drops it off if you pass on two lane and press the throttle to floor then it comes back as soon as you let up , but recirc stays off for a minute or so i seems as you smell outside heat for a minute
in the psd i dont notice of ac clutch cuts off, only the recirc changes. not sure why as engine does not develop vacuum to drive the accessories
not sure what the logarithm is to drive ac compressor off momentarily but i imagine like most vehicles its depends on many variables as in foot speed to wot or 3/4 , and road speed plus engine power demanded
my wifes edge drops it off if you pass on two lane and press the throttle to floor then it comes back as soon as you let up , but recirc stays off for a minute or so i seems as you smell outside heat for a minute
in the psd i dont notice of ac clutch cuts off, only the recirc changes. not sure why as engine does not develop vacuum to drive the accessories
Mountain Pass
Joined: Dec 2020
Posts: 207
Likes: 171
The A/C compressor cycles based on pressure and evaporator temp. The compressor is the same for most gas & Diesel engines, so 1) 3000 rpm is not over revving the compressor, that's cruising speed w/ gas, 2) if you would over rev, the high limit pressure would shut it off to prevent damage, 3) with a 1000 lb/ft of torque, I think the diesel can handle the added load of the compressor.
Don't worry about it
Don't worry about it
Tuned
Joined: Oct 2006
Posts: 449
Likes: 40
I would guess that it may not engage above a certain RPM to save the clutch on the A/C compressor. It's also not uncommon for a/c to be shut off on full throttle (I had a Camaro and I believe this was mentioned in the owners manual). There might be a cut out above a certain RPM (above a certain RPM might cause a cycling on and off rate that would not be acceptable).
Do a/c clutches work as on and off or are they now variable like the fan clutch? The fan clutch is a viscous coupling, like a torque converter.
Do a/c clutches work as on and off or are they now variable like the fan clutch? The fan clutch is a viscous coupling, like a torque converter.
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