Go Back   EcoModder Forum > EcoModding > General Efficiency Discussion
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 04-01-2015, 12:26 AM   #101 (permalink)
Master EcoModder
 
Join Date: Jan 2012
Location: United States
Posts: 1,237

spyder2 - '00 Toyota MR2 Spyder
Thanks: 74
Thanked 201 Times in 149 Posts
Quote:
Originally Posted by ever_green View Post
Yeah the new stratified charge lean burn Hondas might help, but the new Prius can get pretty good mileage on highway without lean burn. Therefore I personally don't see the point.
Well, lean burn is better than cooled EGR like I mentioned for attaining complete combustion. Of course, the biggest problem is getting rid of the NOx, and the current NOx traps are not a good solution.

Since you've experimented with this, do you mind sharing your fueling tables? I'm thinking about getting a BRZ and I'm super excited to fiddle with the ECU (that is, lean burn!). Just to get an idea of how lean you can go at what speed.

  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 04-01-2015, 04:46 PM   #102 (permalink)
Master EcoModder
 
ever_green's Avatar
 
Join Date: May 2011
Location: Toronto
Posts: 260

Blueberry - '17 Mazda Mazda3 GS
90 day: 31.65 mpg (US)

EVO - '08 Mitsubishi Evolution MR
90 day: 22.95 mpg (US)
Thanks: 8
Thanked 76 Times in 31 Posts
Quote:
Originally Posted by serialk11r View Post
Well, lean burn is better than cooled EGR like I mentioned for attaining complete combustion. Of course, the biggest problem is getting rid of the NOx, and the current NOx traps are not a good solution.

Since you've experimented with this, do you mind sharing your fueling tables? I'm thinking about getting a BRZ and I'm super excited to fiddle with the ECU (that is, lean burn!). Just to get an idea of how lean you can go at what speed.
Standard Subaru ecu does not allow you to go leaner than 14.68 Afr or lambda 1.0 in closed loop. What you have to do is induce a fulltime open loop behavior and then have the Maf sensor underestimate airflow by reduce Maf scaling. This is a lot of work as it requires you to reduce the engine load scale across the board in ecu or else it will think there is less cylinder pressure than actually is and run too much timing (this is just one example). Also on the BRZ I highly doubt this is feasible. The direct injection and firing angle tables are extremely confusing and I wouldn't dare tinker with it.
  Reply With Quote
Old 04-01-2017, 04:37 PM   #103 (permalink)
Master EcoModder
 
Join Date: Dec 2014
Location: Radium Springs, NM
Posts: 322

Ford XLT Naked - '14 Ford F-150 XLT
90 day: 15.04 mpg (US)

Ford G-4 with Stinger - '14 Ford F-150 4X4 Super Crew XLT
90 day: 19.8 mpg (US)

Ford Stealth G-4 - '14 Ford F-150 4X4 Super Crew XLT
90 day: 17.78 mpg (US)

XLT Towing Keystone 5th wheel trailer - '14 Ford Keystone 5th Wheel XLT
90 day: 9.71 mpg (US)

Trip 2015 C Max Energi - '15 Ford C Max Energi SWP
90 day: 38.2 mpg (US)

Local 120 volt 2015 C-Max Energi - '15 Ford C-Max Energy SEL
90 day: 55.65 mpg (US)

Local 240 volt 2015 C-Max Energi - '15 Ford C Max Energi SLE
90 day: 58.39 mpg (US)

Energi - '15 Ford C Max Energi
90 day: 101.26 mpg (US)
Thanks: 2
Thanked 411 Times in 196 Posts
I owned a Honda VX for a while (traded it in because it did not have an AC) and the damn thing worked as advertised. We got 55 mpg routinely and sometimes more. Car drove and ran like a sports car if you got on it.
__________________




  Reply With Quote
Old 08-29-2017, 02:19 PM   #104 (permalink)
Panther140
 
Join Date: Jul 2017
Location: Wisconsin
Posts: 46
Thanks: 17
Thanked 6 Times in 5 Posts
The reasons are as follows:
- Combustion stability is too low when running lean (engine knock and/or pre-ignition is caused)
- NOx generation is too high
- Power is decreased
__________________
2007 Silverado 1500 2wd flex fuel with active fuel management. 33" Nitto Terra Grappler tires. 2.5" motofab front end leveling kit.
  Reply With Quote
Old 08-29-2017, 07:04 PM   #105 (permalink)
EcoModding Apprentice
 
ar5boosted's Avatar
 
Join Date: Jun 2017
Location: Sydney
Posts: 110
Thanks: 8
Thanked 19 Times in 16 Posts
Quote:
Originally Posted by pgfpro View Post
To me, their lean burn engine looks like a direct-injection Engine judging by the diagram.

Quote:
Originally Posted by ever_green View Post
What you have to do is induce a fulltime open loop behavior and then have the Maf sensor underestimate airflow by reduce Maf scaling.
Any blog write-ups on that ?

Quote:
Originally Posted by pgfpro View Post
This is a lot of work as it requires you to reduce the engine load scale across the board in ecu or else it will think there is less cylinder pressure than actually is and run too much timing (this is just one example).
I was watching this video. They show it being done on a spreadsheet.

https://youtu.be/kBk0KudOVAg after about 4:20

Using pattern-matching algorithms, I'm really confident that this could be done in software with some type of blanket-algorithm. (True, I don't value car engines like I used to :-) )

Translated into young peoples language, "like a facebook bot? or iPhone app?" but I mean some type of spreadsheet macro or script code.

It's a good conversation, so keep going.
__________________
2003 Renault Scenic - 30% more power with no loss in fuel economy.
1991 Toyota GT4 - more economical before ST215W engine-swap.
previous: Water-Injected Mitsubishi ~33% improved.
future - probably a Prius

Last edited by ar5boosted; 08-29-2017 at 07:21 PM..
  Reply With Quote
Old 08-29-2017, 07:16 PM   #106 (permalink)
home of the odd vehicles
 
rmay635703's Avatar
 
Join Date: Jun 2008
Location: Somewhere in WI
Posts: 2,631

Silver - '10 Chevy Cobalt XFE
Thanks: 219
Thanked 416 Times in 314 Posts
Cool

NOx can react in a fuel cell to make electricity, I wonder why they don't just do that
  Reply With Quote
Old 08-29-2017, 09:09 PM   #107 (permalink)
Ecomuggler
 
Xist's Avatar
 
Join Date: Jun 2012
Location: Mesa, AZ
Posts: 5,262

Chorizo - '00 Honda Civic HX, baby! :D
90 day: 40.43 mpg (US)

Mid-Life Crisis Fighter - '99 Honda Accord LX
90 day: 33.7 mpg (US)
Thanks: 3,179
Thanked 891 Times in 665 Posts
RMay, do you have a source for that? I just get stuff about Bloom Box, which does not mention NOx.

Google does not even bother asking "Do you mean box?"
  Reply With Quote
Old 08-31-2017, 01:10 AM   #108 (permalink)
EcoModding Lurker
 
Join Date: Feb 2008
Location: Washington
Posts: 32
Thanks: 0
Thanked 3 Times in 3 Posts
Quote:
Originally Posted by ar5boosted View Post
To me, their lean burn engine looks like a direct-injection Engine judging by the diagram.
The Honda one (HLSI on that diagram) is port-injected. I think part of what drove Honda to develop this was that they could keep using lean-burn after emissions standards kept them out of cars. They have a bunch of 4-stroke lean-burn outboards, for example.
  Reply With Quote
Old 08-31-2017, 01:22 AM   #109 (permalink)
It's all about Diesel
 
cRiPpLe_rOoStEr's Avatar
 
Join Date: Oct 2012
Location: Porto Alegre, Rio Grande do Sul, Brazil
Posts: 5,605
Thanks: 0
Thanked 534 Times in 479 Posts
Even running lean-burn, port-injection is expected to decrease the NOx emissions compared to direct-injection. Particulate matter emissions, which plagues Diesels and has become an issue for spark-ignited direct-injection too, is another reason for some engines to retain port-injection.
  Reply With Quote
Old 11-07-2017, 06:19 PM   #110 (permalink)
i should weld
 
Join Date: Apr 2017
Location: A hilly area in Western Canada
Posts: 21
Thanks: 1
Thanked 0 Times in 0 Posts
Send a message via Skype™ to ellenor2000
Quote:
Originally Posted by cujet View Post
Those who have aftermarket, stand-alone engine management computers have done some interesting things with lean operation on very modern engines.

Lean operation requires more throttle opening, and the throttle by wire can compensate without driver input. Driveability issues are minimized with such setups.

My current "fun" car is a 2004 Turbo S2000 with stand-alone ECU, 8.8/1 compression, 19.5Lbs boost. It does not run lean under light loads, and does not return very good MPG's. (about 20) . My plan is to re-map the ECU for 17/1 operation under light loads. Those that have done this see overall increases to 25 to 27MPG.

It's my understanding that modern direct injection engines have been configured to operate smoothly at much leaner A/F ratio's. And coupled with high compression, can achieve BSFC numbers almost 25% better than the very same engine operated at stoic.





Take a look at the lower picture. That's my 1971 Cessna 177RG. I'm operating it in very lean mode! (GAMI injectors and other tweaks) I'm achieving a solid 25MPG at 125MPH. I promise, there is no tailwind and I'm actually climbing in this pic. What I do is lower the RPM to 1900-2000, pull throttle to 17 inches manifold pressure and lean it to it loses significant power and misfires a touch, then richen it just a touch. I then fiddle with the controls to achieve a bit less than 5 gallons per hour fuel flow. (the gauge is just to the right of my iPad)

Note: in non lean operation, the same speeds consume about 8GPH.



Look at the airspeed indicator, 113MPH at 4500 feet. That's 125 true airspeed. (remember, the higher you go, the lower the airspeed indicator is for a given speed, due to thin air)
Twentyfive miles per gallon at what, 180km/h? I hope you're able to run UL fuel... If so, that's impressive. If not, LL is leaded and not what we want. Get a conversion to 92UL done and show us your fuel economy running on UL.

That's f'ing impressive

__________________
2002 Ford F-150 XL, rear wheel drive, with the 4.2L V6. "Seemingly low CoG" according to one of my instructors.

80s Ford Ranger 4 wheel drive, with an engine with more blowby than actual expansion. Not officially mine yet, waiting for the plough to come off. Problems: brakes cacked, front diff & axles blown, no C-diff in 4H/4L, engine is a crying child with terminal oil loss which I want to fix, frame rust.
  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com