ac
July-12th-2002, 12:47 PM
#4
Protege Enthusiast
Join Date: Nov 2001
Location: Hamilton, ON
Posts: 323
Originally posted by chikoo
find an open highway.
stop your AC.
cruise at a constant speed and RPM.
start your AC.
observe the engine RPM.
It will have dropped a bit, like 100 rpm.
find an open highway.
stop your AC.
cruise at a constant speed and RPM.
start your AC.
observe the engine RPM.
It will have dropped a bit, like 100 rpm.
Stocker.
July-12th-2002, 01:18 PM
#5
Protege Owner
Join Date: Oct 2001
Posts: 731
Stocker is pretty much 100% right on, but I think that the original post intended to say that if you do not change your accelerator position it will, indeed, drop the RPM of the engine. You need to add a little more gas to maintain a constant RPM once you add any load to the engine.
Just like anything else that loads the engine there is going to be some energy required to run it, that just translates into less energy (HP) to the crank.
I had heard of someone working on a system that during WOT running would clutch the AC system AND the alternator to remove the load during acceleration... once you backed off WOT it would re-engage the alternator and AC compressor. Interesting idea, though I wonder how much the alternator saps off...
Just like anything else that loads the engine there is going to be some energy required to run it, that just translates into less energy (HP) to the crank.
I had heard of someone working on a system that during WOT running would clutch the AC system AND the alternator to remove the load during acceleration... once you backed off WOT it would re-engage the alternator and AC compressor. Interesting idea, though I wonder how much the alternator saps off...
July-12th-2002, 01:29 PM
#6
I am TEH W1N!!!
Join Date: Jan 2002
Location: Calgary, Alberta, Canada
Posts: 2,076
Originally posted by JJB
...I had heard of someone working on a system that during WOT running would clutch the AC system AND the alternator to remove the load during acceleration... once you backed off WOT it would re-engage the alternator and AC compressor. Interesting idea, though I wonder how much the alternator saps off...
...I had heard of someone working on a system that during WOT running would clutch the AC system AND the alternator to remove the load during acceleration... once you backed off WOT it would re-engage the alternator and AC compressor. Interesting idea, though I wonder how much the alternator saps off...
July-14th-2002, 11:31 PM
#7
Certified Sick Individual
Join Date: Mar 2002
Location: Houston, TX.
Posts: 1,141
Kind of cool that your AC does both shutting off at WOT and cycling to minimize the amount of fuel you lose while running it. Thats why its a good reason to move the thermostat rather than the fan when you are using your climate control system. Moving the thermostat reduces AC cycles, moving the fan just consumes electricity, which your alternator is already making in excess anyway.
July-15th-2002, 02:07 AM
#8
Protege Owner
Join Date: Oct 2001
Posts: 731
Originally posted by kc5zom
Moving the thermostat reduces AC cycles, moving the fan just consumes electricity, which your alternator is already making in excess anyway.
Moving the thermostat reduces AC cycles, moving the fan just consumes electricity, which your alternator is already making in excess anyway.
In many cases the fans are a single winding motor. This means it can only run at a single speed proportional to the voltage into it. The speed is the controlled by changing the volatge, and this is usually done by using dump resistors... so that on "low" you dump most of the energy into the resistors and on "high" you just feed the fan full voltage.