Can the Scangauge do this?

[suspectnumber961]

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So what is the Scangauge LOD equivalent of..."100 BMEP" on this chart?



Looks like 2K rpm or a bit lower is about the right place for mpg....

[jakobnev]

It looks like around 70.

[ShadeTreeMech]

Remember, that particular map is good only for the particular car it was created from.

But the article did point out the reasoning behind the pulse and glide technique and why it works so well.

My question is, if having the throttle partly open creates a scenario where the engine isn't in its high efficiency area due to a bit too much vacuum sucking the efficiency downhill, why not add additional exhaust gas to lower the amount of vacuum? (sorry, couldn't resist the pun) The spent exhaust gas would be inert and not create more power, while lowering the manifold vacuum and the associated pumping losses.

And while the scanguage can give you detailed information, it doesn't have a simple LED to alert you to a poor efficiency condition. I would think that little device would be quite a nice fuel saver though.

[euromodder]

Weird explanation of P&G.
Pulsing, then lifting the throttle, i.e. using DFCO ?
That combining 2 wasteful conditions


The Island of Great Fuel Economy, is the island of high BSFC.
Great if you need the power, but usually, like at constant speed, you don't.

I'll happily trade high BSFC conditions for low load, low rpm conditions.
35-45% @ 2000 rpm gives me best real FE.

[mwebb]

..."I'll happily trade high BSFC conditions for low load, low rpm conditions.
35-45% @ 2000 rpm gives me best real FE."...

since you have a diesel engine ....
under that condition your system is most likely operating with around 50% EGR ...
and
your system probably does not have a throttle plate
( if it does have a throttle plate it mostly uses it to create a better difference in pressure between intake and exhaust to enhance EGR flow )
so it always operates at a much higher VE volumetric efficiency than systems that have gasoline engines and throttle plates .

apples and bananas
=================================
Scan Gauge does show real time Fuel economy , just drive while monitoring real time fuel economy to maximize your own results
different
but same end results , you get better fuel economy , use what you have .
if you do not have scan gauge , do not buy it , as ultra gauge and OBDguino or MPGuino can show real time FE
for MUCH less money .
same results for less expenditure

[suspectnumber961]

So here is the BSFC for the 2.0L Zetec engine...an earlier version than mine...but about as close as I'm going to get.



Conclusions?

* looks like ~2000 rpm is most efficient...or where to expect best mpg...though the useful range is probably from 1500 to 2500?

* I have an auto...so it might be hard to keep it in the most efficient area as far as rpm vs LOD?

In real world driving maybe 1700 to 2300 might be most efficient? Which is where I typically drive it. I also run around 45-50 mph most of the time....which puts it in this efficient range in OD.

Gonna be hard to get it into the 120-140 Brake Torque area.....car will go into open loop with some encouragement....

Not really seeing any way to improve driving technique...maybe putting it in neutral when coasting up to stop signs?

Supposedly...higher LOD is more efficient (discounting drivetrain losses?)...meaning I COULD run it up to speed at 2500 rpm and then cruise with a light foot?

Here is a conversion chart for NMs vs LOD...BSFC chart is for another engine....



So most efficient would be 75-85 LOD....but in the real world anything above 50 LOD (up to 85 LOD) and under 2500 rpm would be in the sweet spot???

[tjts1]

Originally Posted by suspectnumber961

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^^^
The fuel smart article posted by the OP is very interesting. I suggest everybody reads it. The way this site interprets the link is unfortunate. There is also a part 2.
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[suspectnumber961]

Below is another version of the Zetec BSFC chart with actual observed LOD numbers roughly translated into torque in NMs. Engine warm on level ground.

From bottom left to top right...


- 42-45 LOD.... cruise in OD at 45 mph and ~ 1800 rpm...seems to be the best mpg area

- 50-54 LOD (24 TPS).... acceleration at a mostly steady 2000 rpm...how I've been driving below 40 mph where the trans shifts into OD

- 66-70 LOD (28-32 TPS).... acceleration at 2200 to 2700 rpms...according to the "BSFC theory"...this type of acceleration SHOULD be more efficient...and more fun? Even funner and more efficient should be in the 2500 to 3000 rpm range?

IF the extra drive train friction losses (auto trans) are offset by the increased efficiency?

The 3rd (oval shape...2200 to 2700 rpms) option would only be used up to 40 mph...where the car shifts into OD...then the pedal would be feathered as usual for best mpg...and the LOD/RPM would drop down to the lower left line.