Go Back   EcoModder Forum > EcoModding > The Unicorn Corral
Register Now
 Register Now
 


Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 12-15-2020, 01:37 AM   #11 (permalink)
EV convert
 
oil pan 4's Avatar
 
Join Date: Jul 2011
Location: NewMexico (USA)
Posts: 9,415

Sub - '84 Chevy Diesel Suburban C10
SUV
90 day: 19.5 mpg (US)

camaro - '85 Chevy Camaro Z28

Riot - '03 Kia Rio POS
Team Hyundai
90 day: 30.21 mpg (US)

Bug - '01 VW Beetle GLSturbo
90 day: 26.43 mpg (US)

Sub2500 - '86 GMC Suburban C2500
90 day: 11.95 mpg (US)

Snow flake - '11 Nissan Leaf SL
SUV
90 day: 141.63 mpg (US)
Thanks: 226
Thanked 3,082 Times in 2,405 Posts
Yeah natural gas engines do some weird stuff.

__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 12-15-2020, 08:51 PM   #12 (permalink)
It's all about Diesel
 
cRiPpLe_rOoStEr's Avatar
 
Join Date: Oct 2012
Location: Porto Alegre, Rio Grande do Sul, Brazil
Posts: 9,568
Thanks: 0
Thanked 1,130 Times in 995 Posts
Quote:
Originally Posted by Isaac Zachary View Post
I don't know if this is possible for gasoline vapor, but I read once somewhere on the all-knowing internet that propane (and natural gas) engines can run much leaner than liquid gasoline engines.
I'm not so used to LPG as a motor fuel, since it's actually only allowed in my country for forklifts and other material-handling equipment not really meant to operate on public roads, but the first vehicle with automatic transmission I drove had been upfitted to also run on CNG besides gasoline. It's possible to run leaner on CNG, since its anti-knock properties are better even than ethanol. But with an excessively lean AFR, power goes down considerably.


Quote:
This also allows for kind of a diesel-like throttling where you can run super lean, keep the throttle valve wide open and adjust throttle by means of introducing more gas (gas as in propane).
It's not so simple to get such a Diesel-like operation, as it remains relying on the spark ignition. It might be also dependent on which generation the CNG conversion kit is based, or if the engine is converted to dedicated-CNG which might enable some different approaches with a stepper motor and a so-called "mixer" instead of a carburettor.


Quote:
On another note, wouldn't the air also have to be very hot to keep the gasoline completely vaporized and dry?
A hotter air intake would eventually require more gasoline to keep its charge cool enough to prevent knocking.


Quote:
Otherwise wouldn't some of the gasoline just condense back into small droplets in the intake charge?
With a colder intake, a smaller amount of gasoline evaporates. Considering the modern engines fitted with EFI, they set a lower AFR exactly to keep the engine at its standard operating temperatures. Notice it in a rainy day, the fuel consumption usually goes down due to the colder air with more moisture on it
  Reply With Quote
Old 12-22-2020, 01:46 PM   #13 (permalink)
Master EcoModder
 
aerohead's Avatar
 
Join Date: Jan 2008
Location: Sanger,Texas,U.S.A.
Posts: 12,784
Thanks: 20,500
Thanked 6,307 Times in 3,907 Posts
anyone

Quote:
Originally Posted by 2016 Versa View Post
I was on You Tube a couple days ago and saw people who claimed to be running their engines strictly on gas vapors from homemade vaporizers. I was just wondering if anyone here has ever tired this and what their outcome was. I can see where it might work but, some of the homemade systems I was seeing didn't look like they would be very safe and some looked like downright fire hazards.
Lindsey published a booklet, with at least a dozen examples, including the 'famous' FISH and POGUE carburetors.
A careful reading leads to the revelation that the carburetors CAN remarkably improve mpg, if you 'push' the car up to 35-mph, start it, then drive 35-mph ( because that's all they it will do ), until you're ready to stop.
__________________
Photobucket album: http://s1271.photobucket.com/albums/jj622/aerohead2/

Last edited by aerohead; 12-22-2020 at 01:47 PM.. Reason: typo
  Reply With Quote
Old 12-22-2020, 02:13 PM   #14 (permalink)
High Altitude Hybrid
 
Join Date: Dec 2020
Location: Gunnison, CO
Posts: 565

Avalon - '13 Toyota Avalon HV
90 day: 41.06 mpg (US)

Prius - '06 Toyota Prius
Thanks: 363
Thanked 187 Times in 138 Posts
Quote:
Originally Posted by cRiPpLe_rOoStEr View Post
A hotter air intake would eventually require more gasoline to keep its charge cool enough to prevent knocking...

With a colder intake, a smaller amount of gasoline evaporates. Considering the modern engines fitted with EFI, they set a lower AFR exactly to keep the engine at its standard operating temperatures. Notice it in a rainy day, the fuel consumption usually goes down due to the colder air with more moisture on it
I think my question is what's the dewpoint for gasoline in air? Let's say you're going for a stoichiometric AFR. What temperature would the air have to be in order to assorb all that gasoline?

You can vaporize as much gasoline as it will boil. But just like a tea kettle that's on the stove, once the steam (vapor) hits the cooler air it forms liquid droplets (the white "steam" that you can see coming out of the whistle). If the air saturates with gasoline the same thing will happen, much of the vapor will transition back into liquid droplets, which you could have gotten the same effect with a good fuel injection nozzle.

The air will have to have a minimum temperature in order to contain purely vaporized gasoline. Any cooler and you get droplets. But how hot would it have to be? Adding more gasoline to cool the intake charge wouldn't help efficiency at this point.

In other words, you boil gasoline in a vaporizer to get gasoline vapor
>but the air is too cool to keep that gasoline as a vapor, so it turns back into droplets, which should defeat the purpose of vaporizing the gasoline in the first place,
>so now you have to heat up the air too so it can hold more vapor without saturating and causing gasoline to condensate back into liquid,
>But now you have a hot dry charge of stoichiometric air and gasoline vapor that causes detonation, knock and maybe even other such problems.
>So the solution is to add more gasoline, which now puts us at a rich AFR, which wouldn't lower the intake charge temperature because no more gasoline can now evaporate because we are at the dew point already, but at least it will evaporate during combustion and hopefully cool the combustion process enough to prevent detonation.
  Reply With Quote
Old 12-23-2020, 05:04 PM   #15 (permalink)
It's all about Diesel
 
cRiPpLe_rOoStEr's Avatar
 
Join Date: Oct 2012
Location: Porto Alegre, Rio Grande do Sul, Brazil
Posts: 9,568
Thanks: 0
Thanked 1,130 Times in 995 Posts
Quote:
Originally Posted by Isaac Zachary View Post
You can vaporize as much gasoline as it will boil. But just like a tea kettle that's on the stove, once the steam (vapor) hits the cooler air it forms liquid droplets (the white "steam" that you can see coming out of the whistle). If the air saturates with gasoline the same thing will happen, much of the vapor will transition back into liquid droplets, which you could have gotten the same effect with a good fuel injection nozzle.
The pressure increase during compression stroke, and the direct proportion between pressure and temperature, is more likely to avoid the gasoline vapors to condense back into liquid, as long as the mixture is not excessively rich.
  Reply With Quote
The Following User Says Thank You to cRiPpLe_rOoStEr For This Useful Post:
Isaac Zachary (12-23-2020)
Old 12-23-2020, 06:27 PM   #16 (permalink)
High Altitude Hybrid
 
Join Date: Dec 2020
Location: Gunnison, CO
Posts: 565

Avalon - '13 Toyota Avalon HV
90 day: 41.06 mpg (US)

Prius - '06 Toyota Prius
Thanks: 363
Thanked 187 Times in 138 Posts
Quote:
Originally Posted by cRiPpLe_rOoStEr View Post
The pressure increase during compression stroke, and the direct proportion between pressure and temperature, is more likely to avoid the gasoline vapors to condense back into liquid, as long as the mixture is not excessively rich.
That gives me an idea! If under experiment we find that the intake temperature has to be higher to keep the fuel vaporized then this could be used in conjunction with a miller cycle engine.

However, then the ability to keep the fuel vaporized could change depending on throttle.
__________________
  Reply With Quote
Old 12-24-2020, 04:00 AM   #17 (permalink)
Master EcoModder
 
Stubby79's Avatar
 
Join Date: Sep 2012
Location: Victoria, BC
Posts: 1,745

Firefly EV - '98 Pontiac Firefly EV
90 day: 107.65 mpg (US)

Little Boy Blue - '05 Toyota Echo
90 day: 33.35 mpg (US)

BlueZ - '19 Nissan 370Z Sport
90 day: 17.19 mpg (US)
Thanks: 75
Thanked 570 Times in 425 Posts
The greater the vacuum, the lower the boiling/vaporizing point, in theory...plus there's engine heat...I doubt you'll have to be worried about it condensating. Except maybe if your engine is dead cold and you've used heat to make it vaporize quicker in the first place. A temporary state, at best.
  Reply With Quote
The Following User Says Thank You to Stubby79 For This Useful Post:
Isaac Zachary (12-24-2020)
Old 12-24-2020, 04:36 PM   #18 (permalink)
It's all about Diesel
 
cRiPpLe_rOoStEr's Avatar
 
Join Date: Oct 2012
Location: Porto Alegre, Rio Grande do Sul, Brazil
Posts: 9,568
Thanks: 0
Thanked 1,130 Times in 995 Posts
Quote:
Originally Posted by Isaac Zachary View Post
If under experiment we find that the intake temperature has to be higher to keep the fuel vaporized then this could be used in conjunction with a miller cycle engine.
There is a Brazilian ethanol-powered Volkswagen-based car which resorted to an intake heater in order to avoid the usage of gasoline for cold starts, and it used only one glowplug mounted on the intake elbow. That glowplug was of the same type fitted to the 1.6L EA827 Diesel.

  Reply With Quote
The Following User Says Thank You to cRiPpLe_rOoStEr For This Useful Post:
Isaac Zachary (12-24-2020)
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com