a substance diffused or suspended in the air, esp. one normally liquid or solid : dense clouds of smoke and toxic vapor | chemical vapors.
• Physics a gaseous substance that is below its critical temperature, and can therefore be liquefied by pressure
MTraveler is correct in his explanation.
As for the difference between “vapor” and “tiny droplets,” gas “vapor” is individual gas molecules that are not longer glommed together (glom being the technical term ;-)). “Tiny droplets” are gas in liquid form, being lots of gas molecules glommed together.
As MTraveler explained, the droplet form is much denser than vapor form, so droplets are better than vapor for introducing a quantity of gasoline into the cylinder.
I wasn’t being serious about the “tiny droplets” vs. “vapor.” In the end a vapor is basically tiny droplets. But that might come down to what you want to say “tiny” and “droplet” means. Follow it to really nail it down and you’ll end up with the astronomers trying to figure out whether or not Pluto is a planet. It was just a goofy, off-hand comment.
No Robert, you don’t want to heat the air to vaporize the gas, power is all about getting the most pounds of air and gas into the cylinder. If you heat it you directly reduce the amount of air and fuel, and therefore power.
^ Correct. But I do NOT want power. I want efficiency. Would be interesting to know if power would be too little.
Power and efficiency are two sides of the same coin. Power comes from volumetric efficiency. Lose one, lose the other. That’s why increasing the compression ratio increases power and efficiency.
Cigroller, no, vapor is not tiny droplets. Vapor is individual molecules that are no longer loosely bonded to other molecules in a liquid phase.
You might say a “mist” is a dispersion of many tiny droplets, but “vapor” is not.
You can mess with the induction process all you want, heat, cold, vapor, gas, whatever…These things were worked out long ago and there is little efficiency to be gained in this area…
The latest improvement in efficiency has come from 9 to 1 compression to 11 to 1 compression, as reflected in the new Mustangs with their astounding performance and fuel mileage…Somehow, Direct Injection allows for this compression increase by avoiding spark knock or detonation…
Smaller engines with lighter reciprocating mass, engines designed to minimize heat loss, here is where they will achieve the new fuel mileage standards…
jesmed - sorry, but it eventually comes down to playing with language. We did not invent the phases of matter. But we have to invent all of the language that goes along with it.
If you want to get down to brass tacks, then you are actually incorrect according to the way chemists/physicists describe things. You might be thinking of a gas - because a vapor is actually in a dual phase of liquid/gas. The whole liquid/vapor/gas thing is - in reality - quite complicated.
I don’t actually care. It was just meant to be a crack in the middle of the conversation.
@jesmed is technically correct. Vapor is created when a liquid eVAPORates. It is described by the ‘vapor-liquid equilibrium’ that occurs at that particular combination of pressure, temperature, and air/hydrocarbon concentration.
“Heathe gasoline and air. You have abundant waste heat available.”
Welcome to the wonderful world of diesels!
Diesels operate by heating the air (via high combustion pressures) and then spraying the fuel into the hot air.
Diesels operate by heating the air (via high combustion pressures) and then spraying the fuel into the hot air.Heat the air beforentering the cylinder to enable more gasoline fumes to be absorbed. Air is also heated in the gasolinengine cylinder through its compression. Just not enough to cause combustion.
Nope, if you heat the air before it goes in to the cylinder it expands, less gas, less power, less efficiency…capiche?
Nope, if you heat the air before it goes in to the cylinder it expands, less gas, less power, less efficiency...capiche?Correct. Heat enough to aid gasolinevaporation into that air.
Let’s try another approach - carmakers have been managing engine heat for decades to optimize fuel vaporization, with hot water passages, air heat devices for warmups, and exhaust heat risers, all to help vaporize the gas during warmup of the car back in the carburetor era. Do you think they’ve suddenly gone ignorant, unable to come up with what would be a simple technique, if it was actually worthwhile?
I think not.
Do you think they've suddenly gone ignorant, unable to come up with what would be a simple technique, if it was actually worthwhile?Correct. They would find what gives them the greatest efficiency and therefore advantage over the competition.
Did any try toptimize fuel economy before the 1970s?
Nope. But 1970 was 42 years ago. A lot has changed in the last 42 years. A whole lot of engineering now goes into fuel efficiency. Has since Jimmy Carter.
Getting enough fuel into an ICE has never been a problem…the 14 to 1 air / fuel ratio is easy to achieve without resorting to extraordinary means…
Most of the time power needs to be restricted by the throttle, not by the laws of physics…
"Did any try toptimize fuel economy before the 1970s? "
Yes indeed! Google MobilGas Economy Run. This was a mileage contest using professional drivers and factory tuned cars that ran during the late 1940’s and 1950’s…Many of those big old Tuna Tankers, supposedly bone stock, could achieve 25MPG or more in the hands of these professionals…
1952 Mobilgas Economy Run Results
Class [By Price Range] Make & Model Ton Miles Per Gallon* Miles Per Gallon Starting Order
A Ford Mainline 6 53.8551 25.4634 14
Studebaker Champion 52.4444 27.8220 5
Plymouth Cranbrook 49.0433 23.5220 20
Ford Mainline 8 48.1744 22.1492 18
Chevrolet Styleline 42.8915 20.5714 12
B Kaiser Deluxe 53.6094 24.6480 24
Studebaker Commander V-8 52.9854 25.5968 22
C Mercury Monterey** 59.7118 25.4093 13
Studebaker Land Cruiser V-8 53.5586 25.3832 27
D Hudson Wasp 47.7830 20.4638 8
Chrysler Windsor 45.9798 19.3599 2
E DeSoto Firedome 8 “6 Passenger” 54.7368 21.2777 29
Hudson Hornet 49.8816 20.8274 15
Hudson Commodore 8 48.8516 20.3973 4
Packard 200 44.9930 19.2278 3
F Chrysler Saratoga 49.1762 19.0237 28
Packard 300 40.8065 16.4211 1
G Lincoln Capri 58.9085 22.3562 17
Chrysler Imperial 52.1844 19.0802 6
H Chrysler Saratoga “8 Passenger” 50.5729 17.6520 9
Packard 400 43.1400 16.9509 16
DeSoto Firedome 8 “8 Passenger” Automatically disqualified - obtained fuel from unofficial refueling station 23
I Chrysler Crown Imperial 53.1736 16.2362 10
Special Lightweight 4-Cylinder Class Henry J - Corsair 4 51.3749 30.8558 19
Special Lightweight 6-Cylinder Class Plymouth Concord 47.0250 23.0797 25
Henry J - Corsair 6 44.8908 26.3676 7
DNS Nash Ambassador 21
Nash Rambler 26
Nash Statesman 11
*Ton Miles Per Gallon = ((Gross Vehicle Weight in Tons * Miles Traveled)/Gallons Consumed), Winning Metric Until 1959
**Sweepstakes [Ultimate] Winner - Mercury Monterey
Average All Cars - 22.0057 Miles Per Gallon
Average All Cars - 49.9901 Ton Miles Per Gallon
Average Speed All Cars - 40.846 MPH
^ Thank you.
Varied winds, humidity, density altitude, etc. creates too manyariables with all of those vehicles.
Was that Mercury Monterey the most “accidentally” aerodynamic?
There has always been a subculture interested in high mileage, but the automotive manufacturers in general did not spend engineering dollars on achieving high mileage prior to the 70’s. None of us really cared much about the cost of gas back then. Heck, stations even used to give away free items (such as drinking glasses) to attract customers.