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t vago 06-09-2013 03:37 PM

EGR experiment (Increase EGR flow for fuel economy)
 
Reference: Increasing EGR flow for better mileage

Today, I modified my EGR system - hopefully for better fuel economy.

First, I took some measurements of my EGR valve. I had a spare EGR valve assembly from a very similar Chrysler engine, so I partially dissected it. The valve controls consist of a solenoid, and a plunger-style potentiometer to measure the solenoid position. The engine computer reads the position of the EGR solenoid (thus, the position of the valve itself), then sends a variable width 128 Hz pulse to the solenoid to open or close the valve to a desired percentage. It goes without saying the the engine computer completely shuts the valve when the engine is idling, at full deceleration, or at moderate (or above) acceleration.

The potentiometer varies along a 2.7k ohm value, and there appears to be a 490 ohm resistance in line with the wiper. Not too concerned about that, though.

Once I got the values, I spliced in a 1 kohm resistor, along with about 3 feet of extra wire, into the EGR sensor supply wire. This willl have the effect of reducing the voltage that the potentiometer sees, thus also reducing the apparent position of the EGR solenoid. The engine computer should then increase the EGR position to compensate.

Looking at the FSM, there does not appear to be any rationality testing for the EGR system. Basically, the EGR valve can pop a code for "No voltage to potentimeter," "Potentiometer shorted to ground," "Potentiometer shorted to supply voltage," or the generic "EGR system not responding." In other words, splicing in the 1 kohm resistor should not pop any codes.

I tested the EGR system with my trusty Snap-on MT2500, and it still responds normally. It's amusing to cause the car engine to start idling horribly when the EGR system is commanded to kick in... Heh. I will take a test drive shortly, and will report my initial feedback here, at some point in the near future.

pete c 06-09-2013 03:50 PM

I am a far cry from any sort of expert on modern engine control systems, but, I wonder if this will cause issues with things as the TPS position will be different from what it thinks it should be.

My guess is that you may have some drivability issues around town but, not so much at steady state cruise on the highway. Maybe wiring things so you could switch between the standard setup and a modified one would be possible once you have attained cruising speed. Perhaps even use a variable resistor so you could fine tune it as you drive.

Good luck with it.

t vago 06-09-2013 08:55 PM

Initial feedback: #@$%^%$&$%^#$

Of course, the car kicked out a P0404 code, meaning that the EGR position sensor performance is faulty. Also, after about 5 minutes of operation, the EGR system got commanded to a continuous duty cycle of 0%. I think the engine computer is not liking that resistor in series with the sensor power wire.

I must tackle this from a different direction, it would seem.

Quote:

Originally Posted by pete c (Post 375624)
I am a far cry from any sort of expert on modern engine control systems, but, I wonder if this will cause issues with things as the TPS position will be different from what it thinks it should be.

I am not sure this will be the case, at least with the TPS. MAP sensor readings might, however, cause the engine computer to throw another code.

Quote:

Originally Posted by pete c (Post 375624)
My guess is that you may have some drivability issues around town but, not so much at steady state cruise on the highway. Maybe wiring things so you could switch between the standard setup and a modified one would be possible once you have attained cruising speed. Perhaps even use a variable resistor so you could fine tune it as you drive.

Yah, that's a good question. I'm not sure this mod is even allowable for my car.

Quote:

Originally Posted by pete c (Post 375624)
Good luck with it.

Thanks! heh...

pete c 06-09-2013 10:20 PM

Sounds like that damn engine computer is a little too smart for its own good. It looks at the various inputs, does the math and says something is screwy. This job sounds like it will require the ability to actually modify the computer's code. Maybe you can get away with smaller changes. Rather than the fixed resistor you added, you could try a variable. Start it at 0 Ohms and slowly increase it, a bit at a time.

Good luck with that! You'll need it.

t vago 06-09-2013 10:41 PM

Yah, I will likely next go with the variable resistor route. I just have to find a small variable resistor (<= 1k ohm or so).

And if that doesn't work, I got a similar EGR valve sitting right beside me. The EGR valve in the car is driven by a pulse-width modulated 128 Hz signal. I'll hook the spare EGR valve up to the engine computer, piggyback the solenoid driver signal into a small microcontroller (likely a Microcore-11, since I have a few of them here that are gathering dust), and use that to drive the actual EGR valve. The microcontroller would then read the variable resistor, and multiply the EGR PWM signal by some percentage determined by the variable resistor.

t vago 06-10-2013 01:04 PM

I could not find any potentiometers smaller than 5k ohms at Radio Shack, and was not willing to wait around for Digi-Key/Mouser to ship me one.

So, I put a 1-pin weatherpack connector on the wire extension I installed yesterday, then installed a 1-pin weatherpack jumper with a 220 ohm resistor on it. Now, I can very quickly switch between stock and added resistance. Hopefully, the 220 ohm resistor will be small enough to be acceptable by the engine computer. If not, I might as well go to plan B above, because I just don't see that it's possible to get any sort of meaningful increase with anything smaller than 220 ohms.

I've added the below table in an attempt to illustrate the # increase in EGR valve opening with the added resistance. "Stock" is what the engine computer would get if it commanded the EGR valve open at a certain percentage, without the added resistance in-line with the position sensor. With the feedback from the valve position sensor with the added in-line resistance, the EGR valve would open to the "modified" percentage value.

% EGR Opening, Stock and with 220 ohm resistor added
StockModified
0.00.0
5.05.4
10.010.8
15.016.2
20.021.6
25.027.0
30.032.5
35.037.9
40.043.3
45.048.7
50.054.1
55.059.5
60.064.9
65.070.3
70.075.7
75.081.1
80.086.6
85.092.0
90.097.4
95.0100.0
100.0100.0

Daox 06-10-2013 01:49 PM

Very cool. I've wanted to do this for a while with my Paseo, but never had the time. Looking forward to seeing how it works out!

AndrzejM 06-10-2013 02:54 PM

Interesting thread. Subscribed :)

t vago 06-11-2013 02:17 AM

Feedback after a 120+ mile commute to and from work: Eh... Maybe?

The engine computer seems to be satisfied with the 220 ohm resistor. There were a few instances where the engine computer appeared to double-check the EGR valve position, both to and from work. However, it did not throw any code, nor does it have a pending code.

If I am to believe the trip fuel consumed figure of 2.24 gallons consumed, on my return leg commute, then it would appear to be that I somehow got 27.1 MPG on that 60.6 mile leg. This would be better than the 24 MPG I would otherwise get on this leg. However, many things occurred which call this figure into question - namely, it rained (so the road was wet for most of the commute), heavier-than-normal 1 AM traffic proved to be somewhat of a challenge, and the turnpike section was completely under construction (forcing me to slow down to below 60 MPH). (side note - You know, Rt 8 well and truly needs to be resurfaced, and has needed it for several years now, but they decided instead to resurface the far left lane of I-80 - which had just gotten resurfaced last year! @$#%#^$)

AndrzejM 06-11-2013 03:11 AM

So maybe that's a good moment for A-B-A test? ;-)

samwichse 06-11-2013 11:17 AM

You might need to make this mod switchable from the driver's seat.

At least on Hondas, I believe right after start the ECM commands full open then full closed to the valve and sets whatever the wiper pot reads as full open/closed values... a sort of recalibration each time its started. If yours does something similar, you might need to splice in a switch to your resistor circuit so you can turn it on after starting.

t vago 06-11-2013 11:53 AM

Quote:

Originally Posted by samwichse (Post 375862)
You might need to make this mod switchable from the driver's seat.

At least on Hondas, I believe right after start the ECM commands full open then full closed to the valve and sets whatever the wiper pot reads as full open/closed values... a sort of recalibration each time its started. If yours does something similar, you might need to splice in a switch to your resistor circuit so you can turn it on after starting.

I've given it quite a bit of thought, and might end up putting in a toggle switch today or tomorrow. To be honest, I don't know if the engine computer only does a start-up recal, or if it continually monitors the sensor circuit for errors.

I have also bought an MPGuino, and will be installing that once it arrives. I'm not terribly trusting of my UltraGauge's MPG readout right now.

Also considering installing some sort of MAF sensor, and building a circuit to convert MAF to MAP. The increased EGR valve opening is causing MAP sensor readings to be somewhat higher than normal, causing the engine computer to pull back ignition timing, which would explain why my UltraGauge now reports spectacularly awful instantaneous MPG readings (11 MPG - 12 MPG) when I am slowly (<40 MPH) going up inclines. It used to report something along the lines of 18-20 MPG.

t vago 06-13-2013 09:27 AM

A few updates:

The UltraGauge did indeed show a highly inaccurate average fuel economy figure. As was mentioned in this post, one should not rely on a ScanGauge or UltraGauge for noting fuel economy due to this sort of mod. This leads to the next update...

The MPGuino should hopefully ship today. If so, I'll install it next week.

First fillup since I did the EGR sensor modification. The results are shown below:

Date/Time
Miles
EngRunTime
Gallons
AvgSpeed (MPH)
FE (MPG)
FE (L/100km)
%diff
Notes
2013.06.05 12:41
334.4
06:06
14.011
54.8
23.9
9.9
2013.06.09 16:19
337.9
07:02
14.333
48.0
23.6
10.0
-1.2
2013.06.13 01:48
398.7
07:13
15.415
55.3
25.9
9.1
7.7
+EGR Mod


I think that a 7.7% increase in fuel economy is not bad.

I'm still considering installing a MAF sensor, and creating a circuit that will obtain a MAP signal for the engine computer. However, I'm also considering moving my IAT sensor so that it will be before my intake heater. This should maybe provide what I want to do, which is to advance ignition timing. Remember, a higher-than-normal EGR will require that ignition timing be advance to compensate for the higher amount of inert gas inside the combustion chamber.

AndrzejM 06-13-2013 09:40 AM

I have EGR which is working just as an on/off valve so your solution won't help me but thanks for sharing! Maybe I'll run a second pipe and second EGR valve someday? I know that Berta had much worse FE when EGR valve stayed closed all the time. So maybe there's some potential. Good to know!

Daox 06-13-2013 10:12 AM

Keep in mind that diesels and gas engines react differently to increasing EGR flow. For gas engines its almost always a good thing (unless you dillute the mixture so much that you get misfires or an incomplete burn). For diesels, balancing EGR is much more tricky. While it can increase efficiency, it generally does not. However, it almost always decreases NOx emissions in both engine types.

Thanks a ton for testing this out t vago. Still looking forward to seeing more results.

maxc 06-13-2013 04:36 PM

On my 1997 f150 I increase the sensor return voltage from the dpfe so the computer advances the timing. With a relay/resister in parallel turned on by the egr. 20 more miles too tank.

mikeyjd 06-13-2013 09:34 PM

7% seems promising
 
Quote:

Originally Posted by t vago (Post 376186)
A few updates:

The UltraGauge did indeed show a highly inaccurate average fuel economy figure. As was mentioned in this post, one should not rely on a ScanGauge or UltraGauge for noting fuel economy due to this sort of mod. This leads to the next update...

The MPGuino should hopefully ship today. If so, I'll install it next week.

First fillup since I did the EGR sensor modification. The results are shown below:

Date/Time
Miles
EngRunTime
Gallons
AvgSpeed (MPH)
FE (MPG)
FE (L/100km)
%diff
Notes
2013.06.05 12:41
334.4
06:06
14.011
54.8
23.9
9.9
2013.06.09 16:19
337.9
07:02
14.333
48.0
23.6
10.0
-1.2
2013.06.13 01:48
398.7
07:13
15.415
55.3
25.9
9.1
7.7
+EGR Mod


I think that a 7.7% increase in fuel economy is not bad.

I'm still considering installing a MAF sensor, and creating a circuit that will obtain a MAP signal for the engine computer. However, I'm also considering moving my IAT sensor so that it will be before my intake heater. This should maybe provide what I want to do, which is to advance ignition timing. Remember, a higher-than-normal EGR will require that ignition timing be advance to compensate for the higher amount of inert gas inside the combustion chamber.

good work ^

t vago 06-14-2013 11:49 PM

Update

I relocated the IAT sensor from its original position, after the intake air heater and before the throttle body, to before the intake air heater. I think this should provide the proper amount of extra spark advance that will compliment the EGR resistor mod.

Intake Air Sensor relocation
http://www.tom-viki.com/spgm/gal/Car...1306140000.jpg

Air Filter Box, Modified with Intake Air Heater - Top View
http://www.tom-viki.com/spgm/gal/Car...1306140001.jpg

Air Filter Box, Modified with Intake Air Heater - Bottom View
http://www.tom-viki.com/spgm/gal/Car...1306140002.jpg

Dummy IAT sensor in original IAT spot
http://www.tom-viki.com/spgm/gal/Car...1306140003.jpg

Induction system, showing Intake Air Heater coolant hoses (and oil catch can)
http://www.tom-viki.com/spgm/gal/Car...1306140004.jpg

AndrzejM 06-17-2013 03:13 AM

Nice setup you have! Haven't seen such a creative air intake heater. Good job! :thumbup:

ECONORAM 08-24-2014 12:20 PM

Another thing that might work for sending a cooler air signal to the PCM is adding a 4.7k ohm resistor to the intake temp wire. I think it's worth a 20* drop in reading.

oil pan 4 08-24-2014 01:34 PM

Wow that's pretty slick how you put the heater core in your air cleaner.

Here is a little idea I had for reusing a diesel EGR cooler:
http://ecomodder.com/forum/showthrea...ler-29085.html

t vago 08-25-2014 09:14 AM

I decided against wiring in a resistor in-line with my IAT sensor, only because I wanted to have a reasonably accurate IAT reading on my UltraGauge.

I have been giving a lot of thought, lately, to retrofitting an EGR system to my truck's engine, since it currently does not have one. It has a cylinder head that has the EGR hole drilled (I had to fabricate and install a block-off plate). I'd just have to get the plumbing, and probably drill a large hole in the intake manifold for the EGR pipe. After that, I'd have to program an Arduino or something to control the EGR valve.

Just remembered - the truck's IAT sensor is positioned after its intake heater. I may have to relocate its sensor, too.

pgfpro 08-25-2014 10:38 AM

Nice work and a great write up!!!:thumbup::thumbup:

old jupiter 08-29-2014 01:15 AM

What an interesting concept! Mixing an inert gas (exhaust gases) with your fresh intake charge to increase fuel efficiency! And more is better?!! Say, why not just run your engine on argon or dry ice??!!

Why do you guys think the factory cuts off the EGR during WOT, when you need the most power out of the air-fuel charge for passing, merging, etc., ??

Why do you think racers of every kind do everything they can to PREVENT exhaust gas dilution of the fresh intake cycle, and have been doing this for maybe ninety years? Why do you think the fire department has inert gases like CO2 in their fire EXTINGUISHERS? But you are going to show us how to get more power and fuel efficiency from a gallon of gasoline by COOLING the fire in your heat-engine. Well, when you figure it out, there are a bunch of multi-million dollar NASCAR teams that will pay you very well for your discovery. :rolleyes:

EGR is for emissions. Period. If the car makers had not been ordered to find ways to reduce photochemical smog (which they decided to do by cooling the burn), there would be no EGR systems on our engines. If the carmakers had been ordered to prioritize the increase the fuel efficiency of cars above everything else including emissions, there would be no EGR systems.

Yes, if you block off the EGR passages (or if the valve plugs with carbon), your engine very likely will run worse. This is NOT because EGR makes an engine run better, but because when EGR is added to an engine, the ignition curve and fuel system calibration are altered to work with the EGR. Basically, because the air/fuel charge is polluted with exhaust gases it burns cooler and slower, therefore the ignition has to be advanced to start the fire sooner. If you blank off the EGR (which is what other folks would do to get more fuel efficiency or power or some combination of the two) you are left with an excessively-advanced ignition, yes, the engine certainly will run worse (until you re-curve for the new conditions).

2000mc 08-29-2014 01:35 AM

Old Jupiter - I don't think anyone is trying to make more power, but would expect to have less power. It's just an inert gas that you make your own supply of. By adding an inert gas, you then draw in less air, and require less fuel by the same ratio of fresh air you are able to displace. From a fuel efficiency stand point, egr makes your engine act like a smaller displacement engine

RustyLugNut 08-29-2014 01:37 AM

Old Jupiter,

Your assessment is entirely correct. However, there is one area extra EGR can be beneficial to overall power and economy. IF the torque output at cruise can be maintained with increased EGR and the same fuel load and the consequently greater throttle opening, the pumping losses at cruise can be reduced. This is after all one of the advantages of the diesel engine over the spark ignition engine.

Running an engine in lean burn can provide much the same effect.

2000mc 08-29-2014 01:41 AM

Entirely correct, except.... Who thought more egr helps power?

t vago 08-29-2014 10:05 AM

Quote:

Originally Posted by RustyLugNut (Post 442913)
But . . .

From his viewpoint, he is entirely correct. Jupiter equates greater power per unit of fuel as greater efficiency as is logical - all else being equal. EGR will not do that unless the gain comes from the aforementioned reduction in pumping losses and a possible increase of combustion speed if the EGR is kept hot. From our viewpoint, reduction of losses (the same as increasing power) per unit of fuel used was not in his discussion. His allusion to increased EGR gaining power was used in the negative as a way to drive home his point.

So... in other words, he's fixated on one aspect of fuel economy, to the detriment of all else.

Quote:

Originally Posted by RustyLugNut (Post 442913)
But, as far as his questioning of the use of EGR for economy boost, he is right.

And how do you propose to show how he is right? Especially as you're enamoured of much-more-questionable methods of increasing fuel economy, than to lower cruising intake vacuum by the introduction of an inert gas.

Quote:

Originally Posted by RustyLugNut (Post 442913)
Tvago is going to need more complete control of his fuel system as he moves forward.

If and when that happens, I'll get to it. Until then, the stock adaptive engine computer seems to be up to the task.

t vago 08-29-2014 10:21 AM

Quote:

Originally Posted by old jupiter (Post 442903)
What an interesting concept! Mixing an inert gas (exhaust gases) with your fresh intake charge to increase fuel efficiency! And more is better?!! Say, why not just run your engine on argon or dry ice??!!

How much fuel does a gasoline spark-ignition engine require, just to develop and maintain an intake vacuum? Why do you think that BMW and others pursue a production version of intake valve throttling?

Quote:

Originally Posted by old jupiter (Post 442903)
Why do you guys think the factory cuts off the EGR during WOT, when you need the most power out of the air-fuel charge for passing, merging, etc., ??

Because ecomodders here constantly do passing, merging, WOT runs, and other things that require full engine output. Riiiiiiiiiiiiiiiiiiiiight.

Quote:

Originally Posted by old jupiter (Post 442903)
Why do you think racers of every kind do everything they can to PREVENT exhaust gas dilution of the fresh intake cycle, and have been doing this for maybe ninety years?

Helpful hint: We're not racers.

Quote:

Originally Posted by old jupiter (Post 442903)
Why do you think the fire department has inert gases like CO2 in their fire EXTINGUISHERS?

Helpful hint: We're not trying to douse combustion altogether.

Quote:

Originally Posted by old jupiter (Post 442903)
But you are going to show us how to get more power and fuel efficiency from a gallon of gasoline by COOLING the fire in your heat-engine.

No. I'm trying to reduce the amount of non-propulsion work my heat engine has to do.

In the meantime, try to explain to me exactly what is accomplished by creating and maintaining an intake manifold vacuum in a gasoline spark-combustion engine. I'll be right here, waiting.

Quote:

Originally Posted by old jupiter (Post 442903)
Well, when you figure it out, there are a bunch of multi-million dollar NASCAR teams that will pay you very well for your discovery. :rolleyes:

Go back to your buddies at DakotaRT.com, and talk about how you and your buddies smoked that Viper the other day.

Quote:

Originally Posted by old jupiter (Post 442903)
EGR is for emissions. Period. If the car makers had not been ordered to find ways to reduce photochemical smog (which they decided to do by cooling the burn), there would be no EGR systems on our engines.

Probably - then again, it's a moot point, because the car makers WERE ordered to find ways to reduce photochemical smog. It's a good thing, too, since that's some nasty stuff.

Quote:

Originally Posted by old jupiter (Post 442903)
If the carmakers had been ordered to prioritize the increase the fuel efficiency of cars above everything else including emissions, there would be no EGR systems.

You do not know that - Given 1970s technology, EGR might still have been a way to increase fuel economy.

Quote:

Originally Posted by old jupiter (Post 442903)
Yes, if you block off the EGR passages (or if the valve plugs with carbon), your engine very likely will run worse.

How is this related to having a controlled increase in EGR flow?

Helpful hint: Engines generally run a lot worse when there is an uncontrolled EGR flow.

Quote:

Originally Posted by old jupiter (Post 442903)
This is NOT because EGR makes an engine run better, but because when EGR is added to an engine, the ignition curve and fuel system calibration are altered to work with the EGR. Basically, because the air/fuel charge is polluted with exhaust gases it burns cooler and slower, therefore the ignition has to be advanced to start the fire sooner.

Ignition also has to be advanced to compensate for high intake vacuum. Why is that?

Quote:

Originally Posted by old jupiter (Post 442903)
If you blank off the EGR (which is what other folks would do to get more fuel efficiency or power or some combination of the two) you are left with an excessively-advanced ignition, yes, the engine certainly will run worse (until you re-curve for the new conditions).

Riiiiight. And all of those mass-produced engine tuners out there (you know, like Hypertech or SuperChips or Diablo) don't seek to deliberately advance ignition curves to improve engine performance. Tell ya what - you stay out of my discussion here, and I'll won't interject my uninformed opinion in any of your discussions that you start here. Fair deal?

t vago 08-29-2014 10:38 AM

One more thing - this goes both to the two individuals above who obviously did not read through this thread, as well as any of their misguided defenders. If EGR modification isn't going to increase fuel economy, then how do you explain this?

Quote:

Originally Posted by t vago (Post 376186)
First fillup since I did the EGR sensor modification. The results are shown below:

Date/Time
Miles
EngRunTime
Gallons
AvgSpeed (MPH)
FE (MPG)
FE (L/100km)
%diff
Notes
2013.06.05 12:41
334.4
06:06
14.011
54.8
23.9
9.9
2013.06.09 16:19
337.9
07:02
14.333
48.0
23.6
10.0
-1.2
2013.06.13 01:48
398.7
07:13
15.415
55.3
25.9
9.1
7.7
+EGR Mod


I think that a 7.7% increase in fuel economy is not bad.


old jupiter 08-29-2014 11:24 AM

Quote:

Originally Posted by 2000mc (Post 442909)
Entirely correct, except.... Who thought more egr helps power?

Well, I assumed (always a risk) that on a fuel economy site everybody wants to put to good use every BTU that a gallon of gas has to move us as far as possible down the road. I'm not a professional writer, and undoubtedly could have been more clear; I'm glad that Rusty got it.

Maybe "power" is some sort of red flag word here, creating images of hairy-armed, semi-literate rednecks burning rubber with their wildly-cammed big-block '60s muscle-cars. But the power in a gallon of gas can be used in many other ways; I really do share your interest in using that potential as frugally as reasonably possible.

At the same time, it should not escape the notice of y'all that racers and other motorsport people, from pre-depression board track races to the present day, are largely responsible for a lot of power-improving techniques that are basic to the fuel-efficiency you want. Cold-air intake ducts, low-restriction air filters, high-atomization from better carburetor boosters and fuel injectors, low restriction intake tracts that help keep fuel in suspension, porting that promotes swirl and tumble (in 4-valve heads), high compression abetted by ever-improving piston crown to combustion chamber conformation and effective squish areas, quick rise-time high-energy long-duration ignition systems, better ring seal and oil control, better coolant flow to avert detonation-promoting hot-spots, ceramic coatings to reduce unwanted heat losses, dozens of machine shop techniques particularly including ones such as platform-honing with torque plates to improve ring-seal, better bearing materials and shapes, precision balancing, low-friction roller-element valve trains that permit better cam lobe shaping, low restriction and wave-tuned exhaust systems, . . . . all these and more are racing engine-building techniques equally useful to eco-modders.

And it doesn't stop with engines; who you think first came up with air-dams and full fender skirts and "full moon" wheel covers to make a car more aero-slippery? You might even thank the racing community for the excellent braking and handling of modern cars. You think the car company engineers did that without a push? Hardly. After WW2, when stock car racing gained popularity in the late-'40s/early '50s, car company executives began taking trips to the (mostly Deep South) races to cheer on their cars. What they saw was their cars wrecked and drivers killed because brakes faded, spindles broke, suspensions collapsed, transmissions and drivelines fell apart. The suits went home and immediately demanded re-designed components that would stand up to the stresses of competition. Racers paid in blood for the capabilities that production cars began to have in the early and mid-'50s.

old jupiter 08-29-2014 11:29 AM

Uh, got a little carried away there. Anyway, if you aren't interested in power, you're certainly going in the right direction. Keep adding EGR and "reducing pumping losses," and soon you'll have that butterfly in your carb or throttle-body wide-open . . . you'll have to because you'll be making so little of that power you don't care about.

Daox 08-29-2014 11:34 AM

The beauty of EGR in this day and age is its electronic and programmable. So, you can have the best of both worlds. You can have the throttle at WOT with tons of EGR pumping in for good fuel economy, or you can close it and get good power. Why does it have to be one or the other? Many OEMs are using a large amount of EGR in their engines to improve fuel economy, yet power isn't sacrificed. Case in point, the new skyactiv engines use a LOT of EGR and still produce great power, and yeah, you get good emissions too. Win win win in my book.

2000mc 08-29-2014 12:40 PM

Quote:

Originally Posted by t vago (Post 442970)
One more thing - this goes both to the two individuals above who obviously did not read through this thread

I don't know that they didn't read it, but somehow took home a completely different message. I considered making a few similar posts to what you just had, but there seemed to be some sort of serious miscommunication going on. It's like we use the same words, but use and define them so differently, that if they were to speak another language and I put it through google's translator, responded back through the translator, and then posted that. That we would likely communicate as clearly if not better

t vago 08-29-2014 02:28 PM

Quote:

Originally Posted by Daox (Post 442980)
The beauty of EGR in this day and age is its electronic and programmable. So, you can have the best of both worlds. You can have the throttle at WOT with tons of EGR pumping in for good fuel economy, or you can close it and get good power. Why does it have to be one or the other? Many OEMs are using a large amount of EGR in their engines to improve fuel economy, yet power isn't sacrificed. Case in point, the new skyactiv engines use a LOT of EGR and still produce great power, and yeah, you get good emissions too. Win win win in my book.

Yah - When I go to retrofit my truck's engine with an EGR valve, it's going to be one of them electronically controlled valves that are common on late model Chryslers. You know, like the one in the Karen-mobile that was the original focus of this thread.

With the truck, though, since it didn't come with EGR to begin with, I don't have to worry much about throwing an EGR-related code. I can program an Arduino Uno to PWM the EGR valve's solenoid coil, and use the EGR valve's position potentiometer to provide feedback. I will try to get the valve to go wide open during light to moderate cruise, and then shut when the brake pedal is pressed, or when throttle position goes above a certain point. The Arduino Uno should be ideal for the prototype, and I can then construct a custom PCB using an AtMega328, once all the bugs are hammered out of the prototype.

MetroMPG 08-29-2014 02:59 PM

Quote:

Originally Posted by old jupiter (Post 442977)
Maybe "power" is some sort of red flag word here...

That's a bit of a misconception. Poke around here a bit more and you'll discover plenty of crossover between power/racing and fuel economy enthusiasm. Lots of owners of "fun" weekend cars + modified-for-efficiency daily drivers.

Quote:

At the same time, it should not escape the notice of y'all that racers ... are largely responsible for a lot of power-improving techniques that are basic to the fuel-efficiency you want. Cold-air intake
Maybe not the best first example. :) Factory warm air intakes can be found on high-efficiency car models. Not good for peak power production, but better for economy (partly for the same reason as EGR -- reduced pumping loss).

t vago 08-29-2014 03:49 PM

Quote:

Originally Posted by RustyLugNut (Post 443018)
And your work wouldn't stand up to the Unicorn Corral requirements.

By your imagination, neither would my aerocap (~10+% gain), or my intake air heater (~5% gain). However, during my last two fillups, my truck would get about 20-21 MPG while driving around at an average speed of 35 MPH. It's (revised) EPA rating is 13 MPG in the city. Explain that.

Quote:

Originally Posted by RustyLugNut (Post 443018)
Here is an example of the testing quality differences.

Am I supposed to imagine what you're trying to show as an example? Here, let me use the power of the Force to try to figure out what you're using...

Quote:

Originally Posted by RustyLugNut (Post 443018)
I don't know what your background is in the physical sciences, but increased EGR for economy gain is as much of fable and legend as HHO. Really.

Prove it.

Daox 08-29-2014 03:51 PM

Here is some proof for you:

http://www.swri.org/3pubs/ttoday/Sum...n-and-Cool.pdf

Their conclusion:

Quote:

The results showed that, by adding cooled EGR systems, it is possible to decrease fuel consumption by 5 percent to 30 percent, with the largest improvement occurring in the typical enrichment region. The results also showed that EGR can reduce knock, resulting in improved combustion phasing with a corresponding decrease in fuel consumption and exhaust temperatures. Adding EGR led to lower peak cylinder temperatures and engine heat rejection, resulting in improved thermodynamic efficiency and a reduced heat rejection requirement from the engine block. Finally, the high levels of EGR used in the study reduced CO emissions by 30 percent and NOx by up to 80 percent. The results indicate that adding high levels of EGR to gasoline engines is a very cost-effective way to reduce fuel consumption as well as emissions.

t vago 09-02-2014 10:04 PM

Quote:

Originally Posted by RustyLugNut (Post 443662)
Continue with your build, but be more realistic by saying "my data implies", since your data is hardly above scrutiny.

EGR, unlike vapor carbs and HHO and plasma plugs and other bits of nonsense, can actually save fuel. The theory is sound regarding using EGR as a fuel saver.

I'm not writing a graduate-level dissertation, here - not the least because it would waste too much of my valuable time, and certainly not to satisfy your own inflated ego as to how things "should be" done. You should be concentrating on actually showing my results to be invalid somehow, not nitpicking in an attempt to show "possible" inaccuracies and pooh-poohing at an 7.7% improvement in efficiency.

When you actually come up with something useful here at EcoModder, I'll be more inclined to consider your point of view. Otherwise, get out of my thread.

t vago 09-02-2014 10:17 PM

Quote:

Originally Posted by RustyLugNut (Post 443661)
Now, at low-load is where t vago's work might make some headway. But look at the SwRI study where they say increasing EGR results in decreasing torque output.

That's.... um.... the entire point.

Increase EGR
-> decreased torque output
-> increased throttle opening
-> lowering intake manifold vacuum
-> restoring torque output
-> saving fuel otherwise spent maintaining a higher intake manifold vacuum

Really, not that hard to understand.

Quote:

Originally Posted by RustyLugNut (Post 443661)
You will have to plot the torque requirements at a certain speed along with the throttle opening to come to the minimum cooled EGR needed. Your ignition timing will need to be adjusted accordingly. With "no throttling losses", you can gain up to 15% in efficiency, but since you are quenching your combustion and reducing your torque potential you will only see an 8% gain, though some of that gain is also due to the thermodynamic advantage of a lower peak combustion temperature lessening the heat loss to the cooling system.

8% gain is better than nothing, and is certainly well above the margin of noise. That alone justifies adding a $0.10 resistor to an existing EGR system, and justifies spending an extra $50 to add an EGR system to another engine that does not have EGR to begin with.

Quote:

Originally Posted by RustyLugNut (Post 443661)
Now, my posts on this thread have been somewhat facetious

Good to know that you're making facetious posts in my thread. Now, do something useful, or get out.


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