Engine combustion.

[dej(Jed)]

Did anyone ever notice how a tractor pulls better as the cool wet evening air is absorbed into the engine? Do you suppose that was becasue of the cooling effect of the water enriched air or because of the extra Oxygen from the water(2H20)? If gasoline and diesel(Carbon/Hydrogen Combinations) don't break down chemically when they are ignited, then where does the C0, C02, SO, S02 and Nox come from? I was told in another post that there is no chemical breakdown and I was just looking for some other opinions?

 

[IaGary]

Part of it is an illusion.

When it's dark you just think or feel like you are going faster than what you are.

I have GPS on my planter and I always find myself going slower at nite but feel like I am going faster than what I was during the day.

Gary

 

[dej(Jed)]

Good point.......

 

[Anonymous-0]

Cool air is more more dense "Heavier" than warm air so it has more oxygen per a set volume that is drawn into the engine.
This is why drag cars go faster on cool days and also the reason for the intercooler on a turbo diesel engine. The intercooler helps release the heat from the air charge after it gets compressed and heated by the turbocharger.

 

[dej(Jed)]

Okay, so the oxygen content goes up somewhat, enriching the mixture and making it burn hotter and better. Just what I thought. Thanks.

 

[JDemaris]

I've noticed several climatic situations where stuff worked better.

At our Deere dealership - we had a fleet of rental diesel tractors. All sat outside, and none had block heaters. We had a few odd days where it could be near zero degrees and just about all would start right up - with no ether. Most other days it would have to be over 30 degrees F - along with ether in some. I always wondered if it had something to do with moisture, atmospheric pressure, etc. Whatever it was or is - I don't know. It still happens with my own stuff at times.

One other situation - my 65 Chevelle SS. If driven real easy, it can get around 16 MPG. 327, Holley 600 carb, Crane mild cam, headers, Muncie four-speed, etc. Once, we were coming home on a 150 mile trip and it was a cold dense fog and light rain the whole way. Just about cold enough to freeze, but not quite. The fog was so dense the air WAS a sort of suspended rain. We got 21 MPG on that trip - and I can't account for it. Normally, I'd never drive that car in weather like that - so I've never had a repeat.

 

[thurlow]

I reckon I never noticed "how a tractor pulls better as the cool wet evening air is absorbed into the engine"; maybe I've just not been paying attention (diesel engines). It's been about 40 years since I ran a gasoline powered tractor, so maybe I've forgotten............

 

[farmer boy]

Fuel has to break down chemically or you would end up with the same thing afterwards. Right? As far as I know all fuels are hydrocarbons and when mixed with oxygen it will create CO2 and H2O. These are the results when you have the correct amount of oxygen. The incorrect amount of oxygen can yield something like CO2 but with less oygen which is where you get carbon monoxide. It will also yield carbon which is the black stuff. If an engine were to get the right amount of oxygen then you could sit in a shed with a car running without having to worry about carbon monoxide poisoning. You would run out of oxygen though. Yes it would make sense that it would pull better at night due to air having a higher density which would mean more oxygen. Now that I think of it why can't the re arrange the whole thing, minus the oxygen and get fuel again? All of the atoms are still there just in different molecular compounds

 

[Anonymous-0]

I remember in the mid 50's I worked for a farmer who had a 30 Massey Harris, with a continental engine. We pulled a 2-14's case plow with it. all day it pulled in 2nd gear and could not hack it in 3rd. When the sun went down you could shift to 3rd, and keep on trucking. The only change was the air. Same field, same tractor, same plow, and same driver.

Thanks
Iowa Bob

 

[Gene Dotson]

No, DEJ, A richer mixture runs cooler. I can lean my airplane to about 1450 degrees, which is best power, but have to enrich it to 1400 degrees to prevent damage.
Water vapor in the air reduces engine power. Water vapor is essentially steam so does not expand within the engine as liquid water does. Humid air is less dense than dry air and will produce less power as the water replaces some of the oxygen.
Cooler air is the primary cause of more power in the evening hours... Gene

 

[Anonymous-0]

Farmer boy, the reason you can't reverse the whole thing and make gas or diesel out of CO2 and O2 is because the burning of the fuel gives off all that energy to plow your field and to reverse that reaction it would take the same amount of energy that burning the fuel gives off. So basically it wouldnt be worthwhile even if it could be done.

 

[Anonymous-0]

This link covers it pretty well.
Temp / humidity VS HP

 

[Brian G. NY]

I think there is a big difference between water vapor and steam. I admit I know practically nothing about physics but it would "seem" to me that injecting water vapor into a firing cylinder might cause it to immediately "flash"
into steam and increase the the power exerted on the piston as steam has hundreds of times as much volume as water.
Of course many things that "seem" to make sense to me have no validity in real life whatsoever!
LOL

 

[Anonymous-0]

I've also noticed that, and always wondered if it was my imagination from getting tired or what. When I was running a big New Holland 4 wheel drive with a disk ripper it would pull better at night, and the RPM's wouldn't drop as much when I'd drop the ripper back in after turning around. It made sense to me that colder air made more power...apparently I'm not crazy.

 

[farmer boy]

Yeah. I kinda thought that it would take massive amounts of energy to rearrange the moceular structure. Oh well, I tried.

 

[Anonymous-0]

That's what I always thought. "It's all in my head" kinda thing. But after listening to the sound of the engine all day in the same field, and hearing how it reacts to extra load...it just seemed stronger after the sun went down and the air cooled off. Never paid any attention to the speedometer reading, but the engine sure did "feel" like it had more power.

 

[buickanddeere]

Rest assured that the bond between the hydrogen and oxygen in water is strong enough that they are not broken when going through the combustion chamber.
If water came apart that easy. Every superheated steam boiler would blow apart from an oxygen/hydrogen explosion.
Bonding free oxygen TO something is easy enough. Happens at room temperature to iron.
Cool air is denser so more lbs of air can pass through per engine rotation.

 

[Aaron Ford]

My grandfather found out about density and temperature during the shuttle raids over Regensburg and Shweinfurt. When fueled at Knettishall, England there was more than enough fuel to make it to North Africa. However, fueling in the hotter climate of North Africa the tanks would not hold enough to get them back. His plane crashed in the rolling hills of England several miles short of the runway. As it was a planned ditch, the crew and the watermelons they brought back from North Africa were unharmed, however the plane was a complete loss.

My little truck runs better in dry weather. Did this since it was new. Valves won't rattle as quick at RPM. Not sure why.

Aaron