Happy sunday everyone, hope you are all enjoying the weekend? Without wasting much of your time, let me go straight to the point.

I have heard a lot of people especially car users complaining about using the AC in their cars simply because it consumes extra fuel.

The question is, does using AC in the car consumes extra fuel? If yes, how? Let's hear your opinion on this......

Babs015:
Happy sunday everyone, hope you are all enjoying the weekend? Without wasting much of your time, let me go straight to the point.

I have heard a lot of people especially car users complaining about using the AC in their cars simply because it consumes extra fuel.

The question is, does using AC in the car consumes extra fuel? If yes, how? Let's hear your opinion on this......

Yes it does.

Generally most cars have been caliberated to take the extra load of the AC and thus for a new cars, you may not feel the difference in the fuel consumption. But as time goes on, and your engine begins to lose power due to wear and tear ( and possibly poor maintenance), the AC load will come to tell on your fuel. Cos the engine will automatically rev a little higher to adequately carry the AC load.

Same thing as when you have a fully loaded car compared to when you're the only one driving.

New or old, AC puts extra load on the engine, and it will consume more fuel to avoid stalling. However, the bigger the engine, the lower the fuel consumption difference.

Last week, I drove a Toyota corolla to Enugu. Due to my itinerary, I had to follow the Owerri route to Enugu.

I took off from Lagos with 45ltrs of petrol. my windows were wound down cos I didn't need the AC that early in the morning but on getting to Benin, the low fuel warning light came on. I was disappointed cos the corolla is not known for high fuel consumption. I pulled out my scanner and scanned the power train even though the CEL was not on and got no codes.

I bought another 45ltrs of fuel in Benin. This time, I needed the AC cos the weather had warmed up. I got to Enugu on half tank of fuel despite taking a longer route and using the AC.

Using the AC would demand more fuel but driving with your windows down will demand much more.

DECOtech:
Last week, I drove a Toyota corolla to Enugu. Due to my itinerary, I had to follow the Owerri route to Enugu.

I took off from Lagos with 45ltrs of petrol. my windows were wound down cos I didn't need the AC that early in the morning but on getting to Benin, the low fuel warning light came on. I was disappointed cos the corolla is not known for high fuel consumption. I pulled out my scanner and scanned the power train even though the CEL was not on and got no codes.

I bought another 45ltrs of fuel in Benin. This time, I needed the AC cos the weather had warmed up. I got to Enugu on half tank of fuel despite taking a longer route and using the AC.

Using the AC would demand more fuel but driving with your windows down will demand much more.

Did you read the topic at all

Pls confirm and re-post

DECOtech:
Last week, I drove a Toyota corolla to Enugu. Due to my itinerary, I had to follow the Owerri route to Enugu.

I took off from Lagos with 45ltrs of petrol. my windows were wound down cos I didn't need the AC that early in the morning but on getting to Benin, the low fuel warning light came on. I was disappointed cos the corolla is not known for high fuel consumption. I pulled out my scanner and scanned the power train even though the CEL was not on and got no codes.

I bought another 45ltrs of fuel in Benin. This time, I needed the AC cos the weather had warmed up. I got to Enugu on half tank of fuel despite taking a longer route and using the AC.

Using the AC would demand more fuel but driving with your windows down will demand much more.

. I have learnt something new and important today so, winding down on highway takes more fuel even higher than when you have AC on.

chidooh1:
. I have learnt something new and important today so, winding down on highway takes more fuel even higher than when you have AC on.

yea, he is right, physics. the air entering will be holding back, like some one wearing agbada and running, you know the wind will blow out the cloth and it will be holding him back, whereas on a smart cloth....easily.
more over, am not always comfortable the wind blowing at high speed.

There are lot to what contribute to the rate of fuel consumption in different vehicles. Driving habits is part of it, miles covered per gallon of fuel has been confirmed to be more on a long distance road without Traffic while less in a stop and go. Some drivers are found of trying to maintain a speed if 100 to 140km/hr without the application of cruise control thereby smashing on accelerator pedal at all time once they notice a slight deceleration in speed not knowing that the more the pedal is depressed the more the fuel injected into the cylinder and in some instances the fuel is waisted away due to excess unused fuel. While driving on a long distance it s advisable the Windows are wound up in order to prevent the vehicle being occupied with air which makes the vehicle to act as is if is carrying extra load.

DGD1:


yea, he is right, physics. the air entering will be holding back, like some one wearing agbada and running, you know the wind will blow out the cloth and it will be holding him back, whereas on a smart cloth....easily.
more over, am not always comfortable the wind blowing at high speed.

U r very intelligent,not like some.

DECOtech:
Last week, I drove a Toyota corolla to Enugu. Due to my itinerary, I had to follow the Owerri route to Enugu.

I took off from Lagos with 45ltrs of petrol. my windows were wound down cos I didn't need the AC that early in the morning but on getting to Benin, the low fuel warning light came on. I was disappointed cos the corolla is not known for high fuel consumption. I pulled out my scanner and scanned the power train even though the CEL was not on and got no codes.

I bought another 45ltrs of fuel in Benin. This time, I needed the AC cos the weather had warmed up. I got to Enugu on half tank of fuel despite taking a longer route and using the AC.

Using the AC would demand more fuel but driving with your windows down will demand much more.

It will takes a wise one to understand an utterance of a wise one.

DECOtech:
Last week, I drove a Toyota corolla to Enugu. Due to my itinerary, I had to follow the Owerri route to Enugu.

I took off from Lagos with 45ltrs of petrol. my windows were wound down cos I didn't need the AC that early in the morning but on getting to Benin, the low fuel warning light came on. I was disappointed cos the corolla is not known for high fuel consumption. I pulled out my scanner and scanned the power train even though the CEL was not on and got no codes.

I bought another 45ltrs of fuel in Benin. This time, I needed the AC cos the weather had warmed up. I got to Enugu on half tank of fuel despite taking a longer route and using the AC.

Using the AC would demand more fuel but driving with your windows down will demand much more.

You have said it all, and that's the truth.
I was explaining this simple phenomenon to some persons and they were like "what's this dude saying?"

chillex8:


Did you read the topic at all

Pls confirm and re-post

Headmaster, You want me to teach physics word to word, abi? are you sure you were able to comprehend what I posted? Cos I'm sure I did not derail the thread.

City driving -windows down. Highway driving- windows up. My reason is this.
For a few minutes (or hours) each day when we do our Iyana Ipaja- Lekki runs, our AC compressor is going flat out, taking power from the engine and in addition both the internal blowers and the electric condenser fans are working hard to cool the car down, causing the alternator to work hard to power them and loading the engine further. Windows down definetely eliminates this need. But if this same car is then used for a long journey,let's say Lagos to Abuja, after perhaps ten minutes, once the internal temperature is reduced comfortably, the AC throttles itself back – its done the hard work, now it only needs to keep the car cool and so now the fuel consumption returns to a much more acceptable level. That's why our ACs seem cooler on long distances than in city driving. Its less stressed, so the engine is also less stressed as well, giving an overall efficient performance. If however, you are still bothered about your consumption rate which may range from negligible to ubiquitous, you may, regardless of driving condition, roll up your glasses and cut off the AC, using only the fan. That way you get the economy and a feeling of comfort. Personally, windows up, AC or not, city or highway. Can't stand dust in car.

disloman:
U r very intelligent,not like some.

thanks.

Wats cruise control

DECOtech:
Last week, I drove a Toyota corolla to Enugu. Due to my itinerary, I had to follow the Owerri route to Enugu.

I took off from Lagos with 45ltrs of petrol. my windows were wound down cos I didn't need the AC that early in the morning but on getting to Benin, the low fuel warning light came on. I was disappointed cos the corolla is not known for high fuel consumption. I pulled out my scanner and scanned the power train even though the CEL was not on and got no codes.

I bought another 45ltrs of fuel in Benin. This time, I needed the AC cos the weather had warmed up. I got to Enugu on half tank of fuel despite taking a longer route and using the AC.

Using the AC would demand more fuel but driving with your windows down will demand much more.

I think one MythBusters episode confirmed this. Above a certain speed (think 90km/hr) a car with the windows down, would burn more fuel because of the poor aerodynamics and consequent wind drag.

Driving in traffic with ac on is a major fuel sucker, especially on a hot afternoon. Ironically that is the most important time to use ur ac because of he hot weather. U might end up using 2 times the amount of fuel in a 2 hours drive in traffic depending on driving condition. On the highway however, it is different, again depending on driving conditions. U will use more fuel if u have a heavy foot and like to accelerate and then brake all the time. U will use less fuel if u take things easy and use ur cruise control on freeways.

abatically:
Driving in traffic with ac on is a major fuel sucker, especially on a hot afternoon. Ironically that is the most important time to use ur ac because of he hot weather. U might end up using 2 times the amount of fuel in a 2 hours drive in traffic depending on driving condition. On the highway however, it is different, again depending on driving conditions. U will use more fuel if u have a heavy foot and like to accelerate and then brake all the time. U will use less fuel if u take things easy and use ur cruise control on freeways.

Does d fan speed also have an effect on d fuel consumption?
Cos I used to a drive a 1.6L volkswagen bora and I noticed acceleration used to be faster at d lowest fan speed as against when it is in 3 or 4 wc is d highest.
I once voiced this opinion to a friend who is a mechanic and he was like once d compressor is on,d fan speed has little or no effect on d movt and fuel consumption but I was of a diff opinion cos I know d car used to drag for longer b4 picking up speed when it's on d highest fan speed.

In city driving with an average speed of about 25km/hr, you will use more fuel with the ac on. The extra fuel will depend on the engine size, outside temperature, driving style and overall engine condition.
Ac increases the load on an engine which in turn increases the amount of fuel injected into the cylinders. Your compressor, fan and blower all add load to your alternator which transfers that load to your engine. That increase in load leads to increase in fuel consumption. On v6 and v8 cars, this extra load is negligible and as such the extra fuel required is equally low. On 4 cylinder engines, the extra load tells. If you plug a scanner with a live reading, you can actually see your load go up and your mpg go down.
On the highway however, it is more efficient to use the ac at speeds above 80km/hr. At this speed and above, wind drag will rob you of fuel economy if your windows are down. But with the windows up and ac on, your car will be aerodynamically efficient and your condenser will cool even better requiring less effort from your compressor and condenser fan which in turn will mean less load on your alternator and engine.
I hope I made sense.

this is informative. thanks Op.

dokyOloye:
Does d fan speed also have an effect on d fuel consumption?
Cos I used to a drive a 1.6L volkswagen bora and I noticed acceleration used to be faster at d lowest fan speed as against when it is in 3 or 4 wc is d highest.
I once voiced this opinion to a friend who is a mechanic and he was like once d compressor is on,d fan speed has little or no effect on d movt and fuel consumption but I was of a diff opinion cos I know d car used to drag for longer b4 picking up speed when it's on d highest fan speed.

More fan speed will demand more energy from your engine but the ecu will compensate for this by raising your engine performance inform of increasing your throttle position to counterbalance the effect.however if you are experiencing drag in your engine performance at high fan speed,try to perform tune up on your throttle body and idle .

I hold unto this point..... (winding down on highway takes more fuel even higher than when you have AC on)

Now i know,,,, Thanks guys....

CC: DECOtech, abatically ....

abatically:
Driving in traffic with ac on is a major fuel sucker, especially on a hot afternoon. Ironically that is the most important time to use ur ac because of he hot weather. U might end up using 2 times the amount of fuel in a 2 hours drive in traffic depending on driving condition. On the highway however, it is different, again depending on driving conditions. U will use more fuel if u have a heavy foot and like to accelerate and then brake all the time. U will use less fuel if u take things easy and use ur cruise control on freeways.

What is cruise control? Is the same thing as Over Drive off/on? What is purpose of Overdrive off/on?

nickxtra:
What is cruise control? Is the same thing as Over Drive off/on? What is purpose of Overdrive off/on?

Cruise control and overdrive on/off are 2 different things. Overdrive on/off is used to prevent the car from selecting the highest gear. For example, if ur car is 4 speed automatic, having overdrive off will prevent the car from shifting to the 4th gear, that is it won't shift past gear 3. It will let the car hold on to lower gears until high rev than in overdrive. Useful when going up a hill and ur car loses power at higher gears, having overdrive off will let the car maintain lower gears until ur rpm is higher.

Cruise control on the other hand is useful on highway especially when there are less cars on the road. It let's u maintain a predefined speed without having to press the accelerator, this greatly helps improving ur fuel economy. It can only be activated at about 60km/hr upwards. The switch is always located on the steering wheel, (some Camry models have it beside the steering where the turn signal is). Let's say u want to maintain a speed of 100km/hr, once u get to that speed, activate ur cruise control, then remove ur leg from the accelerator. The car will drive itself, the ecu will input the right gear and rpm to maintain that speed. All u have to do is steer, u only have to press the brake when necessary, but once u press the brake, the cruise is reset and u have to set it again. However, if u have adaptive cruise control, then ur car will control both acceleration and braking for u once it senses a car in front of u depending on the set distance, all u have to do is steer. Don't try this in city driving though.

abatically:


Cruise control and overdrive on/off are 2 different things. Overdrive on/off is used to prevent the car from selecting the highest gear. For example, if ur car is 4 speed automatic, having overdrive off will prevent the car from shifting to the 4th gear, that is it won't shift past gear 3. It will let the car hold on to lower gears until high rev than in overdrive. Useful when going up a hill and ur car loses power at higher gears, having overdrive off will let the car maintain lower gears until ur rpm is higher.

Cruise control on the other hand is useful on highway especially when there are less cars on the road. It let's u maintain a predefined speed without having to press the accelerator, this greatly helps improving ur fuel economy. It can only be activated at about 60km/hr upwards. The switch is always located on the steering wheel, (some Camry models have it beside the steering where the turn signal is). Let's say u want to maintain a speed of 100km/hr, once u get to that speed, activate ur cruise control, then remove ur leg from the accelerator. The car will drive itself, the ecu will input the right gear and rpm to maintain that speed. All u have to do is steer, u only have to press the brake when necessary, but once u press the brake, the cruise is reset and u have to set it again. However, if u have adaptive cruise control, then ur car will control both acceleration and braking for u once it senses a car in front of u depending on the set distance, all u have to do is steer. Don't try this in city driving though.

Thanks for the info....

DECOtech:
Last week, I drove a Toyota corolla to Enugu. Due to my itinerary, I had to follow the Owerri route to Enugu.

I took off from Lagos with 45ltrs of petrol. my windows were wound down cos I didn't need the AC that early in the morning but on getting to Benin, the low fuel warning light came on. I was disappointed cos the corolla is not known for high fuel consumption. I pulled out my scanner and scanned the power train even though the CEL was not on and got no codes.

I bought another 45ltrs of fuel in Benin. This time, I needed the AC cos the weather had warmed up. I got to Enugu on half tank of fuel despite taking a longer route and using the AC.

Using the AC would demand more fuel but driving with your windows down will demand much more.

Spot on Sir!

Why ur car consumed more fuel with ur windows wound down was due to AERODYNAMIC DRAG effect!

kayswag100:


AERODYNAMIC DRAG effect!

I understand that. Just that the difference was so glaring.

DGD1:


yea, he is right, physics. the air entering will be holding back, like some one wearing agbada and running, you know the wind will blow out the cloth and it will be holding him back, whereas on a smart cloth....easily.
more over, am not always comfortable the wind blowing at high speed.

Aerodynamics

abatically:


Cruise control and overdrive on/off are 2 different things. Overdrive on/off is used to prevent the car from selecting the highest gear. For example, if ur car is 4 speed automatic, having overdrive off will prevent the car from shifting to the 4th gear, that is it won't shift past gear 3. It will let the car hold on to lower gears until high rev than in overdrive. Useful when going up a hill and ur car loses power at higher gears, having overdrive off will let the car maintain lower gears until ur rpm is higher.

Cruise control on the other hand is useful on highway especially when there are less cars on the road. It let's u maintain a predefined speed without having to press the accelerator, this greatly helps improving ur fuel economy. It can only be activated at about 60km/hr upwards. The switch is always located on the steering wheel, (some Camry models have it beside the steering where the turn signal is). Let's say u want to maintain a speed of 100km/hr, once u get to that speed, activate ur cruise control, then remove ur leg from the accelerator. The car will drive itself, the ecu will input the right gear and rpm to maintain that speed. All u have to do is steer, u only have to press the brake when necessary, but once u press the brake, the cruise is reset and u have to set it again. However, if u have adaptive cruise control, then ur car will control both acceleration and braking for u once it senses a car in front of u depending on the set distance, all u have to do is steer. Don't try this in city driving though.

Wao! This is great. Thanks very much. Pls does my Nissan Primera 1999 has the cruise control? Where is located?

nickxtra:
Wao! This is great. Thanks very much. Pls does my Nissan Primera 1999 has the cruise control? Where is located?

No , sorry to burst your bubble

What you need to understand about car airconditioner and fuel consumption http://101carsense..com/2012/12/air-conditioner-fuel-consumption.html

Babs015:
Happy sunday everyone, hope you are all enjoying the weekend? Without wasting much of your time, let me go straight to the point.

I have heard a lot of people especially car users complaining about using the AC in their cars simply because it consumes extra fuel.

The question is, does using AC in the car consumes extra fuel? If yes, how? Let's hear your opinion on this......

It all depends on the speed of the car .Taken from SAE data collated from different sources,
at high speed above 80 km / hr ,if the window is down, the aerodynamic drag increases exponentially relatively to low speed condition , hence fuel efficiency will have decreased by high margin when compared to using ac.
However at low speed or cruising speed , the power produces by the engine is low relative to high speed power , hence the engine need to work harder to maintain the extra load imposed by the ac compressor which hit more on your fuel consumption.
By this fact , you should know the condition when to use your ac if you are mindful on reducing your trip to gas station.