Go Back   EcoModder Forum > EcoModding > Hypermiling / EcoDriver's Ed
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 11-07-2015, 11:45 AM   #61 (permalink)
EcoModding Apprentice
 
Join Date: May 2012
Location: Vallentuna, Sweden
Posts: 129

Phantom Blot (Spökplumpen in swedish) - '75 Saab 96 V4
90 day: 52.77 mpg (US)
Thanks: 17
Thanked 55 Times in 30 Posts
A completely different proof of concept may be a crazy vehicle class we have here in Sweden, the "A-tractors". An A-tractor is originally a normal passenger car, usually a larger RWD. It can also be a 4x4 pickup or even a big truck. The A-tractors are modified for a maximum speed of 30 km/h (around 20 mph) by adding an extra gearbox. The body must be modified so it can't carry lugguage or more than one passenger. The purpose of an A-tractor is to be a cheap "engine" for towing trailers or agricultural tools. As tractor it's allowed to drive by a 15 year with only a quite simple license. (minimum age for car licence in Sweden is 18 years). -Guess you can see now who the average owner of an A-tractor is? Yes, most A-tractor drivers are 15+ teenage boys who don't like to freeze their ass off on a two-wheel moped in the winters. The standard A-tractor is a Volvo 740/940, modified to look like a pickup.

There's A LOT of cheeting with these A-tractors, not only to make them go faster, but also to save fuel. Maximum speed is limitid by gear ratio with the engine running on MAXIMUM speed! For a 2.3 liter Volvo petrol engine this means 5000 rpm at 30 km/h (aprox 20 mph)! Exept for a crazy fuel consumption you have to replace the engine every month or so... Here we talk about 20-40 litres per 100 km!
You simply can't use a street legal A-tractor unless it's a low rpm diesel.

Most A-tractors are therefor illegal with unrestricted gearbox. Some boys drive way to fast but most of them stay below 50 km/h (30 mph). Still these vehicles consume serious ammounts of fuel, often MORE than they did as normal passenger cars. The reason is that there the low engine load at low speed makes combustion seriously inefficient no matter what gear you use. Going 30-50 km/h instead of 70-100 km/h will make almost any car consume a lot more fuel. Obviously it's not pumping losses and friction that is the main reason, it's entirely about engine load. To go slow, you should have a smaller engine!

Diesels are a lot better for slow vehicles and my guess the reason they perform better at low rpm's is the fact that they inject fuel multiple times during each power stroke. In a petrol engine, the entire charge is set on fire at once, increasing heat transfer losses at low rpm's.

__________________
1975 Saab 96 V4, carburetted stock engine. Usually below 4,5 L100 = above 53 mpg (us) by Burn & Glide with engine shut-off. http://ecomodder.com/forum/em-fuel-l...vehicleid=8470
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 11-10-2015, 02:32 AM   #62 (permalink)
EcoModding Lurker
 
Join Date: Jul 2015
Location: USA
Posts: 9
Thanks: 2
Thanked 0 Times in 0 Posts
Question

Thanks to all who have posted on this thread. As a hypermiling novice, it has been a real eye-opener for me. My car is equipped with MPG gauges (instant and average) and a tachometer, but I was wondering if I could use my ScanGauge2 to help determine the optimum rate of acceleration. For example, from reading this thread, I gather I could use the Loop Status gauge to avoid enrichment during acceleration, but could someone help me understand how to use other parameters to determine optimum acceleration, such as Throttle Position Sensor (TPS) or Engine Loading (LOD)?
  Reply With Quote
Old 11-13-2015, 06:24 AM   #63 (permalink)
Master EcoModder
 
Join Date: Jan 2012
Location: United States
Posts: 1,510

spyder2 - '00 Toyota MR2 Spyder
Thanks: 94
Thanked 295 Times in 230 Posts
I would not worry too much about it, just try your best to stay out of open loop, and don't deliberately accelerate slowly. You'll be operating the engine in a relatively efficient way if you do that, and will have gotten most of the possible gains.
  Reply With Quote
The Following User Says Thank You to serialk11r For This Useful Post:
PaleMelanesian (11-16-2015)
Old 11-13-2015, 07:20 AM   #64 (permalink)
2005 Insight
 
Join Date: Aug 2015
Location: Forest Lake, Minnesota
Posts: 23
Thanks: 0
Thanked 7 Times in 6 Posts
Open Loop good and bad?

I have 2005 Insight MT no IMA and need Open Loop clarification.

Example : I noticed if i lift and coast IN GEAR the scan gauge reads Open Loop. It stays in Open Loop till RPM drops Below 1200-1400RPM.
Isn't this the fuel injectors shutting off?

Judging by previous post if I accelerate too hard then the opposite is ture - Open Loop means it is Dumping excessive fuel?
  Reply With Quote
Old 11-13-2015, 08:34 AM   #65 (permalink)
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: Vermont
Posts: 4,130

Gaptooth (retired) - '00 Honda Insight
Team Honda
Gen-1 Insights
90 day: 54.26 mpg (US)

Such Fit - '07 Honda Fit Sport
90 day: 41.27 mpg (US)

Connect - '15 Ford Transit Connect XL
90 day: 23.4 mpg (US)

K-sight - '00 Honda K-sight
Team Honda
90 day: 44.31 mpg (US)
Thanks: 1,933
Thanked 1,738 Times in 1,118 Posts
If you don't have the IMA, there's little reason to coast in-gear unless you're intentionally using the engine to decelerate. Better to drop it in neutral and use a kill switch in most cases.

I suppose that's also "open loop", but the open loop generally refers to those times before the engine is fully warmed up, and near-WOT, where it's not shooting for 14.7:1 AFR and is instead going for a richer and less efficient mixture.
  Reply With Quote
Old 11-13-2015, 09:21 AM   #66 (permalink)
Rat Racer
 
Fat Charlie's Avatar
 
Join Date: May 2011
Location: Route 16
Posts: 4,109

Al the Third, year four - '13 Honda Fit Base
Team Honda
90 day: 42.9 mpg (US)
Thanks: 1,742
Thanked 1,888 Times in 1,224 Posts
Quote:
Originally Posted by skrotbil View Post
... help determine the optimum rate of acceleration.
Optimum is determined after the fact. The car is a closed system, but it operates in the real world. Outside conditions take what the car does and turn that into real numbers, so what is optimum in one place at one time in particular traffic and weather conditions and in a particular gear won't be optimum if you change any of those things.

YMMV, as it were.

Fun, huh?

I tried using load and throttle % back when I started, even instant gph. I ended up settling on instant, short trip and tank mpg. Theoretical efficiency inside the block is moot if it's not being applied well.
__________________

Quote:
Originally Posted by sheepdog44 View Post
Transmission type Efficiency
Manual neutral engine off.100% @MPG <----- Fun Fact.
Manual 1:1 gear ratio .......98%
CVT belt ............................88%
Automatic .........................86%

  Reply With Quote
Old 11-13-2015, 11:34 PM   #67 (permalink)
EcoModding Lurker
 
Join Date: Jul 2015
Location: USA
Posts: 9
Thanks: 2
Thanked 0 Times in 0 Posts
I have a 2015 Toyota with 6-speed automatic 2AR-FE engine. In addition to Eco Drive mode, it is also equipped with an Eco Driving Indicator. Quoting from the manual: "During Eco-friendly acceleration, Eco Driving Indicator Light will turn on. When acceleration exceeds Zone of Eco driving, the light turns off."

Following suggestions of others in this thread, I started monitoring Engine Load (LOD) on my ScanGauge, trying to accelerate steadily with a target load of around 80%, but each time I do so, the Eco Driving Indicator light goes out, telling me I have exceeded Eco-friendly acceleration. To stay within the so-called Zone of Eco acceleration, I have to accelerate very slowly and gently.

BSFC maps would seem to suggest otherwise, but as I have no specific map for this engine, I've done as Fat Charlie suggested and ditched the LOD and TPS gauges and just monitor the instant MPG on my car's display and try to adjust my driving accordingly. Trying to monitor LOD, TPS, LP, and MPG, I sometimes forget to watch the CAR in front of me.
  Reply With Quote
Old 11-14-2015, 07:20 AM   #68 (permalink)
Master EcoModder
 
Join Date: Sep 2009
Posts: 5,927
Thanks: 877
Thanked 2,019 Times in 1,302 Posts
Don't think I would want to trade miles per gallon for miles per front end sheet metal.

regards
mech
  Reply With Quote
Old 11-14-2015, 06:28 PM   #69 (permalink)
Rat Racer
 
Fat Charlie's Avatar
 
Join Date: May 2011
Location: Route 16
Posts: 4,109

Al the Third, year four - '13 Honda Fit Base
Team Honda
90 day: 42.9 mpg (US)
Thanks: 1,742
Thanked 1,888 Times in 1,224 Posts
Ignore what the car tells you, with its Zone Of Stupidity.

Don't even watch the gauges too closely- you're not trying to hit a moving needle, you're trying to get to work. Take each acceleration event as a whole: I gave it this much gas, got to that speed, and it did this to my trip mpg. Instant mpg will be horrible while accelerating hard, but that's okay. What matters is what you do with it overall.
__________________

Quote:
Originally Posted by sheepdog44 View Post
Transmission type Efficiency
Manual neutral engine off.100% @MPG <----- Fun Fact.
Manual 1:1 gear ratio .......98%
CVT belt ............................88%
Automatic .........................86%

  Reply With Quote
Old 11-14-2015, 09:30 PM   #70 (permalink)
Intermediate EcoDriver
 
Mustang Dave's Avatar
 
Join Date: May 2009
Location: Northern Arizona - It's a DRY cold..
Posts: 667

Trigger - '07 Ford Mustang V6 Premium Coupe
Team Mustang
Sports Cars
90 day: 30.66 mpg (US)

Big Red (retired) - '89 Ford F-250 4wd Custom
90 day: 18.13 mpg (US)

Big Red II - '13 Ford F-150 FX4
Pickups
90 day: 19.66 mpg (US)
Thanks: 162
Thanked 127 Times in 100 Posts
Quote:
Originally Posted by Fat Charlie View Post
Ignore what the car tells you, with its Zone Of Stupidity.

Don't even watch the gauges too closely- you're not trying to hit a moving needle, you're trying to get to work. Take each acceleration event as a whole: I gave it this much gas, got to that speed, and it did this to my trip mpg. Instant mpg will be horrible while accelerating hard, but that's okay. What matters is what you do with it overall.
Well stated. Acceleration is bad for fuel economy. Try not to waste too much time accelerating.
When driving home from work, I enter I-40 eastbound on an up-hill on-ramp. I don't drive with an egg on the accelerator; I drive with a deck of cards under it. I push the accelerator to achieve 100% load on my Ultra Gauge without going into open-loop enrichment. I shift at 2500 RPM. Instantaneous MPG is about 6.9 MPG in 3rd gear; 9.9 MPG in 4th gear; and 13 MPG in 5th gear while accelerating to 65 MPH. I set cruise control @ 65 MPH while still on the on-ramp. Driving in town and in rural neighborhoods, I generally shift at 1500-2000 RPM - still accelerating @ 80-100% load. I know I'm doing a few things wrong, but 32+ MPG (6 month average) isn't THAT bad for a 4.0 liter Ford Mustang.

__________________
Fuel economy is nice, but sometimes I just gotta put the spurs to my pony!



Quote:
Originally Posted by thatguitarguy View Post
Just 'cuz you can't do it, don't mean it can't be done...
Quote:
Originally Posted by elhigh View Post
The presence of traffic is the single most complicating factor of hypermiling. I know what I'm going to do, it's contending with whatever the hell all these other people are going to do that makes things hard.

Last edited by Mustang Dave; 11-15-2015 at 02:38 AM..
  Reply With Quote
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