Do higher combustion temperatures mean better fuel efficiency?

[CManT1914]

Correct me if I'm wrong, but do higher combustion temperatures mean a more efficient burn? I know the hotter the engine, the more power is lost, but wouldn't you gain some fuel efficiency? There's got to be a reason Ford designed our cars to run around 210*. Emissions right? If I were to let the car run at 210 consistently as opposed to 180 like I have been, wouldn't it get better gas mileage? Just a thought...

 

[illwood]

Chris, I think it's more of a question of exhaust emissions than fuel efficiency.

I would imagine that your cooler running engine should get slightly more MPG because the motor is making more power so you don't have to rev it as much or give it more gas to keep a constant speed under load.

Where I believe the hotter engine, the burn tends to remove NOxs and whatever else they measure for emissions (maybe it's better for the cats).

 

[AznStanger3v]

Chris, I think it's more of a question of exhaust emissions than fuel efficiency.

I would imagine that your cooler running engine should get slightly more MPG because the motor is making more power so you don't have to rev it as much or give it more gas to keep a constant speed under load.

Where I believe the hotter engine, the burn tends to remove NOxs and whatever else they measure for emissions (maybe it's better for the cats).

Burning hotter makes MORE oxides of nitrite. That is why we have an EGR that takes inert gases and sends them into the combustion chamber during cruising to displace some of the air to keep temps down and improve gas mileage while reducing NOx levels. phew, say that without stopping.

 

[illwood]

Burning hotter makes MORE oxides of nitrite. That is why we have an EGR that takes inert gases and sends them into the combustion chamber during cruising to displace some of the air to keep temps down and improve gas mileage while reducing NOx levels. phew, say that without stopping.

Makes sense, but isn't emissions why Ford has our cars running at 210* factory?

There has to be something reduced at the tailpipe for there to be a good reason.

 

[CManT1914]

Makes sense, but isn't emissions why Ford has our cars running at 210* factory?

There has to be something reduced at the tailpipe for there to be a good reason.

I believe emissions are the reasons Ford set the fans to not come on until 210 or wherever it's at (mine would never get above 210 before I wired my fan switches, leading me to believe the fan turned on automatically at 210, but I'm not sure). I was just wondering if there are any fuel efficiency gains from running at this temperature. It would not make sense for me to be running around the street burning more fuel just to be running at 180.

 

[stud4u13]

haveing your car run cooler will make it run more rich and thus waste gas. BEcause your ECT is reading cool so it tells the computer to dump more gas to bring temps up. Depending on how much gas is being dumped could make your car start to lose power also due to running to rich. If you have cats then they get clogged up and also create a restriction in the exhaust also reducing power. So running that cold may not be the best idea depending on how stock you engine is

 

[HISSIN50]

Actually when the car is near optimal (per its programming, not our desires) temps, it can lean out in order to bring temps up (lean causes heat). And since the car is for all intents are purposes 'hot', some leanness wont cause stalling like it would on a cold motor.

I like to keep the ECT at 178+ on the fox (that is when the ECT recognizes full CL, even though the O2's have long since lit off and are allowing fuel to be trimmed). I would like to keep the SN cooler (I am doing all that I can), but in 110* temps, it wants to run at 205-210*F.