Warmer engine but cooler fuel?

 

Hotter is better (to a point).  Thats why alot of new car thermostats are 205 F.  Supposedly, smokey yunick had some experimental engine where the fuel was heated too to improve economy. 

the new technology is amazing, too

 

I do not think there is any one answer, due to all the differences in engines, and fuel systems.
My general thinking is the warmer the engine, the less the fuel/air mixture is wasted bringing the combustion chamber up to the combustion temperature, and can be put into power. I think the fact that we need to richen up the mixture when the engine is cold (Choke), helps support my thinking.

Why did all the automakers get away from air cooled engines? I think its a combination of weight savings, and better drivability with fuel injection, which is hard to do with air cooled engines. I bet if you look into it, most air cooled engines have more weight per HP produced.

  Thats my 2cents

 

I do not think there is any one answer, due to all the differences in engines, and fuel systems.
My general thinking is the warmer the engine, the less the fuel/air mixture is wasted bringing the combustion chamber up to the combustion temperature, and can be put into power. I think the fact that we need to richen up the mixture when the engine is cold (Choke), helps support my thinking.

Why did all the automakers get away from air cooled engines? I think its a combination of weight savings, and better drivability with fuel injection, which is hard to do with air cooled engines. I bet if you look into it, most air cooled engines have more weight per HP produced.

Thats my 2cents

explain porsche's success making lots of power with a air cooled engines

cold air makes denser fuel air charge ,more power,but more fuel used .
hot air makes leaner , less power
warm air is the happy medium , power & fuel economy.

 

explain porsche's success making lots of power with a air cooled engines

Better yet, explain why they did not keep the idea after so long.

 

Better yet, explain why they did not keep the idea after so long.

1938-1998 is not long? seems like a good long run to me ,
And that's a lot longer run than other water cooled engines

 

1938-1998 is not long? seems like a good long run to me ,
And that's a lot longer run than other water cooled engines

You are reading things that I did not say. I asked "why they did not keep the idea after so long. "The answer is that for economy, power, and engine longevity you need better control of engine temps then can be done with air cooled engines. I think its BMW that has the computer controlled thermostat, giving different engine temps for different conditions, Which itself speaks volumes as to the importance of engine temps.

There is still many air cooled engines made, but none of them are known for economy. My welder has a Wisconsin 4 cyll air cooled engine in it, its 1/2 the cubes of a 318, but over 2/3 the weight.

 

You are reading things that I did not say. I asked "why they did not keep the idea after so long. "The answer is that for economy, power, and engine longevity you need better control of engine temps then can be done with air cooled engines. I think its BMW that has the computer controlled thermostat, giving different engine temps for different conditions, Which itself speaks volumes as to the importance of engine temps.

There is still many air cooled engines made, but none of them are known for economy. My welder has a Wisconsin 4 cyll air cooled engine in it, its 1/2 the cubes of a 318, but over 2/3 the weight.

you're kidding right ? the Porsche /vw air cooled engines were reliable ,fuel efficient and made plenty of power in a low cc displacement and lightweight .
It also costs less in maintenance than a water cooled .
Look at most motorcycles -air cooled
Very few are strictly water cooled

I didn't read it wrong , you may have wrote it wrong , but your point still makes little sense

the major draw back in air cooled cars is the heating systems suck ,
And emission hydro carbon output is high,
That was reason they changed .
To pass today's high emissions standards .
and properly maintained air cooled will outlast a water cooled engine and at less cost !

 

  Ok, to get past this, and back on track, I'll agree with you, what ever your point is.

 

Air cooled engines on road vehicles are falling out of favor due to emissions.  The temperature of the combustion chamber fluctuates more with an air cooled engine rather an a liquid cooled.  More and more bikes are going to water cooling or oil-air cooling adn it's due to emissions and nothing else.  Compared to the air cooled engines they replaced, with bikes the liquid cooled engine of comparable horsepower is heavier in weight, has the issue of finding a place to mount the radiator/s and is more complex when you consider the water pump, thermostat and such.  They do tend to be quieter and don't have the fin ring (noise) some air cooled engines have.

As for coolant temp, the colder it is, the worse the fuel economy.  I remember when 160 degrees was the norm, then 180, then 195 and now many are 205-210.  The best fuel economy I ever got with my water cooled bike was on the 2007 trip.  Ambient temperatures averaged 100-110F day after day and my bike was running hotter than a firecracker.  I had to scrounge up a 3 ring binder, TV antenna, wire, nail and a rock to fashion a shroud to force more air into the radiator to keep the red light from going off.  And with my air cooled bike, I could average 40-42 mpg day after day, but run in steady rain where the water cools the engine down and keeps it cool, mileage would routinely drop to 22-24 mpg.  When the rain quit and the road dries, back to 40+.

As for air temp with normal coolant temps, back in the days of the 60 mph interstate speed limit, I would run my D150, 318, 2bbl and 3,21 axle to Chicago and back, a 820 mile round trip.  I made that trip plenty of times and in the summer I'd average 17, in the winter 16 mpg year after year (figures were actual, corrected due to inaccurate speedo-odo).  Just my experiences, although I must admit that I've always been kind of anal about keeping track of fuel consumption on any vehicle.

 

In my mind I think that a warmer overall engine temperature will improve fuel economy because it allows for better combustion.

HMMMM Greg, your mind is definitely not a terrible thing.

What it all comes down to, when the engine is warmer, it creates more power per unit of fuel simply because less heat from combustion is transferred into the block and heads.

Would anyone care to argue with me about this, Kendall? Under "pressure", I could always "expand" upon the subject if necessary.

 

HMMMM Greg, your mind is definitely not a terrible thing.

What it all comes down to, when the engine is warmer, it creates more power per unit of fuel simply because less heat from combustion is transferred into the block and heads.

Would anyone care to argue with me about this, Kendall? Under "pressure", I could always "expand" upon the subject if necessary.

I'd like to see a lego diorama on how warm engines produce better fuel economy.

From what I gather- warmer fuel is more efficient. Fuel is warmed

I find it hard to believe air cooleds last longer than water cooleds. Lot of water cooleds out there with >1 million miles of many varieties. I could believe there's no weight savings or efficiency advantages- though wouldn't be surprised if there was more consistency.

 

Cooler fuel has traditionally led to better atomization and more power.  What has suddenly changed about that or have racers had that wrong for the past 60 years?

 

But is more power more economical? 

You need to have carb, or intake heat to help vaporize the fuel before it enters the combustion chamber. You cannot argue that cold engines need a richer fuel/ air mixture (Ie, a choke). Too cold gasoline will not vaporize fully, allowing raw fuel to enter the combustion chamber, which will not burn.

 

I thought that was the point of "atomization".

verb (used with object), atomized, atomizing.
1.
to reduce to atoms.
2.
to reduce to fine particles or spray.
3.
to destroy (a target) by bombing, especially with an atomic bomb.
verb (used without object), atomized, atomizing.
4.
to split into many sections, groups, factions, etc.; fragmentize:
Critics say the group has atomized around several leaders.

 

The effect of temperature is a trade off between fuel density (cold) and atomization. When it's colder, you get more fuel. However, efficiency comes when you can burn it better, so when it's warmer it will be more volatile exposing more surface area to oxygen.

Ideally, you would have very cold fuel under high pressure for maximal atomization (exposing more surface area for combustion). That's one of the reasons diesel engines have been more economical in mpg (aside from higher energy content).  This is also why you're now seeing GDI engines - the higher injection pressures lets it atomize better (in addition to reducing fuel mix reversion, etc).

 

I'd like to see a lego diorama on how warm engines produce better fuel economy.

All you'll see is a steaming kaleidoscopic pile of melted and charred ABS plastic and even sooner if Kendall fails to lubricate it again, 85.

 

Referring back to the orginal question....

If you have EFI, and your coolant temp sensor is bad (usually read way low) then the ECM will stay in warm-up mode and pound through fuel. BTDT 

 

Cooler fuel has traditionally led to better atomization and more power. What has suddenly changed about that or have racers had that wrong for the past 60 years?

To my thinking that has to do with the inherent cooling of the intake tract and an overall denser charge. High compression race motors can get away with it, or take advantage of it if you will, because the high squeeze preheats the mixture prior to ignition, with the vaporization of the fuel droplets taking place in the chamber instead of the intake tract. Vapor fuel takes up more space in the intake than liquid droplets do, one of the problems associated with making power on propane. {BTU's aside}

No fuel taking up space in the intake combined with the higher compression ratios {some are 10+ now} is where a lot of today's engine efficiency comes from. That and computer micro management. I think another reason manufacturers raised engine temps is because of the aluminum heads/blocks used now days. A cool dense charge and a hot chamber is the idea.

Who'da thunk we'd ever see 700+ hp and 20+ mpg from an American V8?

 

Cooler fuel has traditionally led to better atomization and more power. What has suddenly changed about that or have racers had that wrong for the past 60 years?

Is that what it is, or is it preventing vapor lock and maintaining consistency?

 

That's what they have claimed for years for cool cans, carb spacers and other similar parts.

 

All you'll see is a steaming kaleidoscopic pile of melted and charred ABS plastic and even sooner if Kendall fails to lubricate it again, 85.

Sheesh, you bring it up over and over and over again, yet you still won't tell us what would change. I tell you that your line of thinking is impossible, yet you never have a response. You just ignore it, and bring it up again later.

 

Sheesh, you bring it up over and over and over again, yet you still won't tell us what would change. I tell you that your line of thinking is impossible, yet you never have a response. You just ignore it, and bring it up again later.

You seem to have a mighty selective memory there, Thalzheimer. How many times did I tell you if the spider gears exhibit excessive friction or otherwise bind up for any reason, the differential will act like either a limited slip or a locker?

 

I'll spell it out.

In the example we've discussed in the past (straight ahead travel, to keep it simple) and in the example of my Lego model......

The wheels are directly connected to the side gears. Do you know and understand this?
Therefore, if both wheels (left and right) are going the same speed and they both have traction, both side gears are rotating at the exact same speed as each other as well as the whole diff assembly.
If the side gears are rotating at the same speed, then the spider gears CANNOT rotate! They stay in place (which one could argue is acting like a locker....but not really) but not because of a lack of lube or any binding, it is because both wheels have traction and therefore will be turning the same speed.

When in a turn, then the side gears are going different speeds and THEN the spider gears will slowly turn but it is still only biasing power to each wheel, not sending it all to one and none to the other. That only happens when one wheel loses traction.

You could put as much lube of any kind of your choosing on a spider gear, and it is still not going to spin if both wheels are going the same speed, it can't, it physically cannot. No way, no how. If you still believe it can, attempt to explain yourself.

 

I'll spell it out.

In the example we've discussed in the past (straight ahead travel, to keep it simple) and in the example of my Lego model......

The wheels are directly connected to the side gears. Do you know and understand this?
Therefore, if both wheels (left and right) are going the same speed and they both have traction, both side gears are rotating at the exact same speed as each other as well as the whole diff assembly.
If the side gears are rotating at the same speed, then the spider gears CANNOT rotate! They stay in place (which one could argue is acting like a locker....but not really) but not because of a lack of lube or any binding, it is because both wheels have traction and therefore will be turning the same speed.

When in a turn, then the side gears are going different speeds and THEN the spider gears will slowly turn but it is still only biasing power to each wheel, not sending it all to one and none to the other. That only happens when one wheel loses traction.

You could put as much lube of any kind of your choosing on a spider gear, and it is still not going to spin if both wheels are going the same speed, it can't, it physically cannot. No way, no how. If you still believe it can, attempt to explain yourself.

I cant help but agree with these cold, hard facts. Facts are stubborn things... - John Adams