Increasing EGR flow for better mileage

[Cobb]

I met up with JimE one day who had an Insight EGR on the bench. I have been meaing to modify it so the valve is always open and take a spin around the block to see how it impacts.

I imagine with a honda hybrid it would help regardless as mo throttle would equal mo assist with the Insight design. Kind of the reverse of a prius which would go from electric to gas, but Ive been fooled before by modern technology

I can say the newer insight is much more drivable with it blocked off and I lost 3 mpg doing so.

[oil pan 4]

Originally Posted by Cobb

I met up with JimE one day who had an Insight EGR on the bench. I have been meaing to modify it so the valve is always open and take a spin around the block to see how it impacts.

Expect rough idle and stalling.
Typical fun symptoms of a stuck open EGR.

[christofoo]

Hmm. I'm on the lookout for a throttle-loss-reduction method for the masses.

After reading the opening post it occurs to me that some kind of active EGR control system add-on might qualify, but I've got a question I want to throw out:

Would such a thing be considered tampering with an emissions control system, and thus be illegal?

If the answer is yes, I think a longer answer is that if emissions were not physically increased, presumably such a device could get tested and receive clearance with the EPA as an aftermarket device. (Although from my point of view regulatory clearance requirement is undesirable, if it's avoidable.)

(Sorry for the side-track.)

[RobertISaar]

i can attest to that....

GM's "digital" EGR setup used from the late 80s-1995 that have 3 solenoids to make a combintation of 8 flow rates(without accounting for the change in flow from manifold and exhaust pressure), if i command on the smallest solenoid at idle, there's quite a stumble, eventually gets close to it's normal idle characteristics. medium solenoid, large RPM dip, almost enough to stall the engine. usually won't get close to it's idle stability, fuel mixture noticably off due to the O2 sensor running into it's correction limit. then you trigger the large solenoid... usually stalls, but if it doesn't it idles horribly.

[christofoo]

Originally Posted by MetroMPG

PS: anyone planning to mess with EGR will need an MPGuino or equivalent to properly measure the effects on fuel consumption.

The ScanGauge will not report fuel consumption properly under high EGR concentrations for the same reason it doesn't work well with lean burn.

I think the EGR enters via intake manifold, but the MAF sensor is upstream, i.e. in the snorkel. If so the ScanGauge should be accurate regardless of EGR manipulation. Is that right?

[RobertISaar]

how does the scanguage calculate fuel economy?

two possible methods, one of which is significantly better than the other but requires more information.

method 1 is estimating fuel injected based on airflow readings from the MAF sensor and the target air/fuel ratio.

method 2 is calculating fuel injected based on injector pulsewidth, RPM, injector flowrate, number of injectors and injection scheme to create a fuel flowrate in gallons per hour.

guess which one is more accurate?

[christofoo]

Originally Posted by RobertISaar

how does the scanguage calculate fuel economy?

two possible methods, one of which is significantly better than the other but requires more information.

method 1 is estimating fuel injected based on airflow readings from the MAF sensor and the target air/fuel ratio.

method 2 is calculating fuel injected based on injector pulsewidth, RPM, injector flowrate, number of injectors and injection scheme to create a fuel flowrate in gallons per hour.

guess which one is more accurate?

Scangauge uses MAF. MPGuino uses injector pulsewidth, and is more accurate generally, and significantly more accurate on lean-burn engines.

[oil pan 4]

Originally Posted by christofoo

Hmm. I'm on the lookout for a throttle-loss-reduction method for the masses.

Get people to buy more diesels.

[christofoo]

Originally Posted by oil pan 4

Get people to buy more diesels.

Apples and oranges. 1) New equipment vs retrofit, or minor retrofit vs gut (sorry if I wasn't clear on intent, aiming at fleet, not new). 2) Still not the same (potential) category as petrol in smog emission terms (SULEV/PZEV), broadly speaking, although there's some buzz about even cleaner diesels on the horizon. Diesel Zone | Car Talk "Cars labeled with California's Ultra-Low Emission Vehicle ("ULEV") and Super Ultra-Low Emission Vehicle ("SULEV") standards both pollute less than the new diesels."

[Teemo]

Hello!

Anyone tried out the cooled EGR system in practice on (gasoline engine)?

I modified my car yesterday to test it out: The cooled exhaust gas is taken from near the end of the exhaust pipe and runs through the installed pipe to the intake manifold.
Test car is 1990 passat with 2.0 doch engine.
Currently I do have no regulator valve for the egr. I just pinch the hose with clamp to get the desired flow. I have adjusted so that the car is still able to idle, opened up the idle screw fully. Bad that this engine have mechanical injection, so there is no easy way to measure the fuel consumpion(mpguino). I will take longer trip some day soon and lets see if I notice some fuel saving.