EGR VALVE: when is it open and what makes it shut?
#1
EGR VALVE: when is it open and what makes it shut?
I have a couple questions regarding the EGR valve.
I'm curious to know if the EGR valve shuts off above a certain rpm. It seems that if I highway cruise below 3000rpm I can get between 27-30mpg but if I go past that threshold the fuel economy drops down to around 23-25mpg.
Does the EGR valve shut off above a certain rpm?
Thanks in advance!
Jon
I'm curious to know if the EGR valve shuts off above a certain rpm. It seems that if I highway cruise below 3000rpm I can get between 27-30mpg but if I go past that threshold the fuel economy drops down to around 23-25mpg.
Does the EGR valve shut off above a certain rpm?
Thanks in advance!
Jon
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#8
This also would correlate with the percentage of EGR that is normally recycled back to the intake charge. Now there are many factors that come into play with the limits of EGR but typically 15% is the most EGR that can be back into an engine running on gasoline. Above that number you start seeing your hydrocarbon emissions going through the roof because of incomplete combustion & random misfires.
What I'd like to do is explore the limits of EGR by either going to a stepper motor driven EGR valve, like those on other Mitsubishi vehicles and having the factory ECU modified to control it. There are some worthwhile dividends to be paid by getting better control of EGR.
I know it's not a Prius but we could all stand to get a few more miles out of a tank of gas.
On a side note, those who run E85 could really boost their fuel economy being that you can run upwards of 40% EGR without pissing off combustion.
Jon
#9
Evolved Member
iTrader: (18)
Interesting concept, it looks like our cars have a simple EGR system. I don't know if the open loop tables have anything to do with EGR, but maybe raising the load threshold to stay in closed loop at a higer load may keep the egr on over 3k rpm.
toyota manuals always seem more educational than others http://www.autoshop101.com/forms/h61.pdf
toyota manuals always seem more educational than others http://www.autoshop101.com/forms/h61.pdf
#10
EvoM Guru
iTrader: (50)
This should provide the info to allow you to figure out the drop in mileage:
https://www.evolutionm.net/forums/sh....php?p=5474289
You might have to do a little logging to figure out exactly what's happening.
https://www.evolutionm.net/forums/sh....php?p=5474289
You might have to do a little logging to figure out exactly what's happening.
Last edited by mrfred; Mar 29, 2008 at 08:48 PM.
#11
This should provide the info to allow you to figure out the drop in mileage:
https://www.evolutionm.net/forums/sh....php?p=5474289
You might have to do a little logging to figure out exactly what's happening.
https://www.evolutionm.net/forums/sh....php?p=5474289
You might have to do a little logging to figure out exactly what's happening.
NOTE TO SELF: READ ALL ECUFLASH THREADS!
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