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Does A Car Consume More Fuel When The AC Is On HI Than On LO - Car Talk (2) - Nairaland

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Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by doskie(m): 6:26am On Apr 11, 2016
ogbiwa:
Pls I've been asking this question for sometime now. Does fuel consumption on AC vary with the various LO, MID HI AC levels or it consumes same amount once the AC is switched on regardless of the level. However i think my engine power changes as I either increase or reduce my AC. Auto gurus abeg food don done.
experiment it yourself.
buy fuel, run ac on lo and see how long it last.. do the same with it on hi making sure you cover the same distance, same quantity of fuel and same load ( number of people and goods)
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by kuntash: 6:26am On Apr 11, 2016
Now ,

Let's do small practical ..

You crank the engine , put on the AC , after a while , disconnect the fan blower while the compressor is still working ....

You would discover in no time that the evaporator would be caked with ice ...and the thermostat would usually do it's job and shuts off the compressor ....

The more air that blows thru the evaporator that prevents that caking of ice the longer the compressor stays working ..



Does that make any sense ?
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by tete7000(m): 6:29am On Apr 11, 2016
Sunymoore:
No! Because, a car compressor is either mechanically on or off, so setting it to hight is only increasing the blowers speed, and that will cause slight fuel consumption, because the fan is an electrical component, so running at high speed will make it to use more power from the alternator, thus increasing your fuel consumption with slight margin...
So, in summary is No! Due to negligible increase in fuel consumption...

Slight increase over a long distance or over a long period of time in an holdup becomes significant. Did you think of this?
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by seaga: 6:44am On Apr 11, 2016
No Ac on high doesn't increase fuel consumption .It's that simple.when you switch on your Ac the belt and compressor pulley adjust so as to make the compressors roller active.So what makes it consume more fuel is simply more load the compressor generates while active irrespective of what you do on your dash it's still the same ,everyother thing is electrical and it's the evaporator (located behind your dashoard at the very center )that now conditions the temperature.Besides when Ac is on high is just the blowers rotating speed you increase pushing out the moist the compressors generates through the hoist faster.To buttress this, check car owner's manual it's stated that your car will consume more when Ac is on and not mentioned if you change the fan speed. That notion is really absurd and silly. undecided
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by NigerianScholar: 6:52am On Apr 11, 2016
ogbiwa:
Pls I've been asking this question for sometime now. Does fuel consumption on AC vary with the various LO, MID HI AC levels or it consumes same amount once the AC is switched on regardless of the level. However i think my engine power changes as I either increase or reduce my AC. Auto gurus abeg food don done.
Dont mind some people. Putting your ac on ' HI' just consumes battery. Because d fan wuld b rolling faster. Just like putting on d car when when the engine is not running. You are only stressing d battery.
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by NigerianScholar: 6:53am On Apr 11, 2016
honmusa:

You already know the answer that increasing your AC level is like putting more load on your engine which is equivalent to more fuel consumption .Your ECU will need step up your engine performance to keep your engine from stalling which is why you will definitely feel the drag on your engine the more with AC at the highest level.

U r rong
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by joey150(m): 6:54am On Apr 11, 2016
what the op should have done was carry out a real time test himself while driving.. Then google search your results from that test online to see if its true.

But trust Nigerians.... We want everything done for us in this modern age.
Same reason we dont have any functioning research centers in this country.

And yes...more ac=more load. Higher temp=more running time for the ac . so higher temp=higher fuel consimption. (since we talking ac(cooling)..it should be lower temp) am trying to make it easier to understand.
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by Sunymoore(m): 6:56am On Apr 11, 2016
tete7000:


Slight increase over a long distance or over a long period of time in an holdup becomes significant. Did you think of this?
Of course, but dont forget, air drag caused by relatively high speed on a long distance will consume more fuel than AC..
That of hold up might be possible, but still the amount that will be consumed is not going to break a neck, because no excess horsepower is added to the engine
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by OKorowanta: 7:01am On Apr 11, 2016
Nice thread.car wahala too plenti.
Had a completely flat tire on Friday on third mainland bridge.
Imagine!
Dat kind lagoon view.
Thank god for one of those guys dat ply d road with bikes looking out for pipo with such discomfort.

1 Like

Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by seaga: 7:03am On Apr 11, 2016
To the doubting Thomas,stop that argument it is silly.Now op when you get into your car switch your Ac on high ,then press the Ac button off ,you will realise the blower is still blowing high whereas the compressor is idle, so that means it's electrical not mechanical

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Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by Osyxcel(m): 7:13am On Apr 11, 2016
NigerianScholar:

Dont mind some people. Putting your ac on ' HI' just consumes battery. Because d fan wuld b rolling faster. Just like putting on d car when when the engine is not running. You are only stressing d battery.

You really need to get informed.

Your battery doesn't do anything once your car is started. The alternator generates all the electrical energy needed once the car is on (including charging the battery). The only time your battery will work while the car is running is when your alternator is bad and that will kill your battery.

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Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by leuelliot(m): 7:19am On Apr 11, 2016
all dis one na big big talk, my car go soon make petrol extinct. d tin de consume less fuel with A/C on sef cry
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by martineverest(m): 7:24am On Apr 11, 2016
kuntash:


Partially correct especially for vehicles with bad or faulty thermostats ....

The regulation of the working of the compressor is directly proportional to the rate @ which the cabin evaporator condenses ....which in turn is altered by the fan speeds
" evaporator Condenses": Never heard of that before
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by AsanwaKC(f): 7:28am On Apr 11, 2016
yes it does, just like increasing load on your generator. more fuel will be consumed
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by martineverest(m): 7:38am On Apr 11, 2016
kuntash:
Now ,

Let's do small practical ..

You crank the engine , put on the AC , after a while , disconnect the fan blower while the compressor is still working ....

You would discover in no time that the evaporator would be caked with ice ...and the thermostat would usually do it's job and shuts off the compressor ....

The more air that blows thru the evaporator that prevents that caking of ice the longer the compressor stays working ..



Does that make any sense ?
don't also forget that without the blower, those ice will melt( when the thermostat stops the compressor);thus, the car gets wet
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by FTBoi: 7:43am On Apr 11, 2016
seaga:
To the doubting Thomas,stop that argument it is silly.Now op when you get into your car switch your Ac on high ,then press the Ac button off ,you will realise the blower is still blowing high whereas the compressor is idle, so that means it's electrical not mechanical
but it's only when the compressor is on you feel the sudden jerk of power drain in the engine. but with just the blower on, you wouldn't notice anything. i've experienced that many times......it's funny how people come here to tell otherwise..
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by slap1(m): 7:46am On Apr 11, 2016
Siena:


With the older magnetic clutch-type compressor (fixed displacement) once the clutch is engaged, the engine will use a bit more fuel. Altering the temperature setting will NOT increase fuel consumption, however altering the blower speed will affect fuel consumption marginally, due to more voltage being drawn, and therefore more load on the engine via the crank-driven alternator.

With the later clutchless-type compressor (variable displacement) fuel consumption is proportional to temperature setting. This is because it has the pistons mounted on a swash plate. Altering the temperature alters the angle of the swash plate from shallow to steep, with the steepest angle giving more piston swept volume, and therefore more load on the engine. Altering the blower speed will have a marginal effect on fuel consumption as in the older system.

The Igwe has spoken! cheesy
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by professore(m): 7:50am On Apr 11, 2016
So increasing/reducing the level of the A/C has no implication on the compressor but on the blower (blower fan) nice.
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by hucienda: 7:59am On Apr 11, 2016
Siena:


With the older magnetic clutch-type compressor (fixed displacement) once the clutch is engaged, the engine will use a bit more fuel. Altering the temperature setting will NOT increase fuel consumption, however altering the blower speed will affect fuel consumption marginally, due to more voltage being drawn, and therefore more load on the engine via the crank-driven alternator.

With the later clutchless-type compressor (variable displacement) fuel consumption is proportional to temperature setting. This is because it has the pistons mounted on a swash plate. Altering the temperature alters the angle of the swash plate from shallow to steep, with the steepest angle giving more piston swept volume, and therefore more load on the engine. Altering the blower speed will have a marginal effect on fuel consumption as in the older system.

wow.. Looks like you're a Mechanical Engineer.. Man wey sabiii! Prof on Vehicle Matters.. #HatsOff
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by MyX1: 8:06am On Apr 11, 2016
Osyxcel:


You really need to get informed.

Your battery doesn't do anything once your car is started. The alternator generates all the electrical energy needed once the car is on (including charging the battery). The only time your battery will work while the car is running is when your alternator is bad and that will kill your battery.
How factual is this Info?
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by crackhouse(m): 8:11am On Apr 11, 2016
@op, u have done a bad job by bringing this issue here. I bet u, u will be more confused after this issue must have been thrashed out here. Just be ready for the "I too knows" to invade ur thread and put more confusion on your head.
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by ogmaskman: 8:12am On Apr 11, 2016
SammyGyang:
No. Once the compressor picks, it consumes same amount of fuel whether it's on "HI" or "LO". That's what a lot of Nigerians fail to understand.

I do not agree with you sir. The compressor shuts down faster with the fan on low. This means that the fuel consumption is reduced compared to when the car blower is on high which delays shut down of the compressor. Note that the blower fan blows the air thru the evaporator into the cabin. The compressor on the other hand responds to the level of coolness of the evaporator. the evaporator cools faster with the blower on low, which means faster shut down. with the blower on hi, the evaporator takes more time to cool. The longer it takes to cool the evaporator the longer it takes the compressor to shut down. As you know, the longer it takes the compressor to shut down the more fuel it consumes. As far as the compressor is on, the engine responds appropriately.

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Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by MyX1: 8:18am On Apr 11, 2016
ogmaskman:


I do not agree with you sir. The compressor shuts down faster with the fan on low. This means that the fuel consumption is reduced compared to when the car blower is on high which delays shut down of the compressor. Note that the blower fan blows the air thru the evaporator into the cabin. The compressor on the other hand responds to the level of coolness of the evaporator. the evaporator cools faster with the blower on low, which means faster shut down. with the blower on hi, the evaporator takes more time to cool. The longer it takes to cool the evaporator the longer it takes the compressor to shut down. As you know, the longer it takes the compressor to shut down the more fuel it consumes. As far as the compressor is on, the engine responds appropriately.
GBAAAAAAAAAAMMMMMM!
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by eseoghene144: 8:23am On Apr 11, 2016
No difference with my car
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by donciccio: 8:34am On Apr 11, 2016
Siena:


With the older magnetic clutch-type compressor (fixed displacement) once the clutch is engaged, the engine will use a bit more fuel. Altering the temperature setting will NOT increase fuel consumption, however altering the blower speed will affect fuel consumption marginally, due to more voltage being drawn, and therefore more load on the engine via the crank-driven alternator.

With the later clutchless-type compressor (variable displacement) fuel consumption is proportional to temperature setting. This is because it has the pistons mounted on a swash plate. Altering the temperature alters the angle of the swash plate from shallow to steep, with the steepest angle giving more piston swept volume, and therefore more load on the engine. Altering the blower speed will have a marginal effect on fuel consumption as in the older system.

Siena! Siena!! Siena!!! Why have you forsaken us? Can't believe you're still on this platform. Good to hear from the father of automobile. But next time present a layman's explanation too. Anyway, we're waiting for you to postulate some automobile laws.
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by achu442(m): 8:46am On Apr 11, 2016
I no like too much argument.
Put 20 litres of fuel,Drive from Lagos to Ore with your AC on High

THEN

Do the same while coming back with your AC on low and check the amount of fuel consumed.

Practical answers.

1 Like

Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by ricki: 9:12am On Apr 11, 2016
Worst sef it consumes more fuel when stationary(not moving) tok less wen ac is on....
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by niquidanner(m): 9:13am On Apr 11, 2016
Yes it does consume fuel..i can say this due to the experience I have using Toyota.The Compressor one the vehicle is a start and stop process,meaning once the gas freeze for sometime it stops for few seconds then starts again..thus in this process it puts more load on your engine and that makes it consume more fuel...

Now answering your Question

If the fan speed is placed on Low,the compressor works for about 50 seconds before its stops,if its MID,its works longer before it stops and same thing applied to HI.The load is placed on the engine and Yes it does consume more fuel

1 Like

Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by clintino700(m): 9:25am On Apr 11, 2016
Just like saying when someone is shouting and when talking on a low(normal) tune.. Saying the same amount of energy is been consumed during these two actions...

I.e more fuel tends to be consumed when the AC is been increased!!!
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by Freeman50(m): 9:42am On Apr 11, 2016
ogbiwa:
Pls I've been asking this question for sometime now. Does fuel consumption on AC vary with the various LO, MID HI AC levels or it consumes same amount once the AC is switched on regardless of the level. However i think my engine power changes as I either increase or reduce my AC. Auto gurus abeg food don done.
when the car Ac is on, the speed of the car won't to be active unlike when the Ac is off. The higher the Ac the higher fuel it consumes. You will understand better for instance, when you might have powered a refrigerator with a generator, consumes more unlike when lesser appliances are powered with generator.
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by 100Cents: 9:55am On Apr 11, 2016
ogbiwa:
Pls I've been asking this question for sometime now. Does fuel consumption on AC vary with the various LO, MID HI AC levels or it consumes same amount once the AC is switched on regardless of the level. However i think my engine power changes as I either increase or reduce my AC. Auto gurus abeg food don done.

The HI MID and LOW indicators are controlling the AC fan which control the speed at which cold air is blown into the car.

So a higher turn on the knob will consume slightly higher energy than a lower turn. Even the OX standing fans at home change the sound of your mini generating set when you high them.
Re: Does A Car Consume More Fuel When The AC Is On HI Than On LO by richard870(m): 10:03am On Apr 11, 2016
ogbiwa:
Pls I've been asking this question for sometime now. Does fuel consumption on AC vary with the various LO, MID HI AC levels or it consumes same amount once the AC is switched on regardless of the level. However i think my engine power changes as I either increase or reduce my AC. Auto gurus abeg food don done.
Ofcourse, cuz it speeds up the combustion rate of the engine due to its thermal nature
A good example is wot happens wen u plug a pressing Iron....sudden reduction in the gleam of the light right? Dats exactly wot happens wen ur car Ac is on. It speeds up the rate of engine combustion

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