fraz91 wrote:I've actually got my bluetooth OBDII adapter set to give me a readout on when the EGR is actually in operation (only what's commanded, not the actual). The EGR is closed under full open throttle (so full acceleration and full engine braking), but is open the rest of the time. How far it's open depends upon the boost pressure, and the more the boost goes up, the more the EGR closes.
There's no possible way for the EGR to push clean air through the exhaust to give better emissions. If this was the case, then the exhaust would have a breather on it at the start that sucked cold and clean air through to make the emissions look better.
coxy47 wrote:Wow that took me a long time to write. Fraz is right about how the egr operates but it was never intended to push clean air through the system so that the exhaust gases are leaner. See my previous post
Well mostly right, the egr will open at idle at least in the ML . As the egr valve opens the throttle closes mostly so that exhaust gases are not pushed back through the intake system.
odie602r wrote:... and all that was going through my mind was 'is 16% increase in fuel usage a fair trade for no carbon in the manifold' ...
(BTW, I have now successfully tee-ed in a one way valve on MAP sensor line, thanks srb. Road trip tomorrow, so see if that restores the economy).
fraz91 wrote:I've actually got my bluetooth OBDII adapter set to give me a readout on when the EGR is actually in operation (only what's commanded, not the actual). The EGR is closed under full open throttle (so full acceleration and full engine braking), but is open the rest of the time. How far it's open depends upon the boost pressure, and the more the boost goes up, the more the EGR closes.
There's no possible way for the EGR to push clean air through the exhaust to give better emissions. If this was the case, then the exhaust would have a breather on it at the start that sucked cold and clean air through to make the emissions look better.
Tony wrote:Lets remind our selves why the EGR system in in place.
Basically the idea is to feed lower oxygen exhaust gas into the intake.
Our diesel EGR systems are designed to lower combustion temperature resulting in reducing emissions of NOx. This makes combustion less efficient and compromising economy and power. Diesel EGR as we are all aware increases soot production, this has been overcome in some cases with diesel particulate filters. (Has me buggered why the smaller diesels haven't adopted the idea) The EGR systems can also add abrasive contaminants and increase engine oil acidity, which in turn can reduce engine life.
FACT.......Engine manufacturers have refused to release real details of the effect of EGR on fuel economy, the EPA regulations of 2002 that led to the introduction of cooled EGR were associated with a 3% drop in engine efficiency.
What we see is lower Nox production with lower combustion temps, more fuel, more soot and higher EGTs
I find it fascinating some of us see higher fuel usage due to the EGR removal. More a tuning issue no doubt.
odie602r wrote:... and all that was going through my mind was 'is 16% increase in fuel usage a fair trade for no carbon in the manifold' ...
(BTW, I have now successfully tee-ed in a one way valve on MAP sensor line, thanks srb. Road trip tomorrow, so see if that restores the economy).
odie602r wrote:... and all that was going through my mind was 'is 16% increase in fuel usage a fair trade for no carbon in the manifold' ...
(BTW, I have now successfully tee-ed in a one way valve on MAP sensor line, thanks srb. Road trip tomorrow, so see if that restores the economy).
coxy47 wrote:Fair point. I'm definitely wrong on that one. My apologies.
I do apologise if I've said anything else wrong as well in my previous few posts. It's not exactly unlikely I'd much rather be corrected then continue to be wrong while thinking I'm right.
srb wrote:I also have my Ultra gauge setup to see the EGR open and shut percentages. Mine is usually 100% open when I first start up in the mornings, then slowly shuts to around 45 - 69% driving around town. It does fluctuate with stop start driving and like you said it closes completely under full acceleration and engine braking. And it also opens up 100% at highway speeds. It's interesting to see it work under different conditions ay.
sierra wrote:srb wrote:I also have my Ultra gauge setup to see the EGR open and shut percentages. Mine is usually 100% open when I first start up in the mornings, then slowly shuts to around 45 - 69% driving around town. It does fluctuate with stop start driving and like you said it closes completely under full acceleration and engine braking. And it also opens up 100% at highway speeds. It's interesting to see it work under different conditions ay.
Srb,
I asked Fraz91 the same question.
When you say the EGR being open or closed and the % do you mean the EGR valve that lets the cooled exhaust in or the throttle valve that limits the air?
sierra wrote:odie602r wrote:... and all that was going through my mind was 'is 16% increase in fuel usage a fair trade for no carbon in the manifold' ...
(BTW, I have now successfully tee-ed in a one way valve on MAP sensor line, thanks srb. Road trip tomorrow, so see if that restores the economy).
No, 16% higher fuel consumption isn't a fair trade, especially since most of us seem to have gained better economy and earlier boost.
I'm pleased you're trying the one way valve mod and looking forward to hearing how it works out. I'm sure srb made it clear which way around it goes, which is critical.
If you still have lousy fuel consumption you could try disconnecting the throttle valve for a tank to see what effect that has?
You can use the scanguage to remove the CEL if it irritates you but it shouldn't do any more than that and give you a lumpy shut down, less engine braking too.
odie602r wrote:Man, that's frustrating, that's for sure. Most people put in the blank and get an improvement - I put it in and it goes the other way. Still can't understand why it would do different things with different Triton's. I fill up the tank tomorrow and will see true economy again then, but it hasn't brought a smile to my face yet. Is there any logical reason why it isn't constant on every vehicle?
Yeah, I'm pretty sure the one way valve is the right way around - so that the direction of air is into the vacuum hose.
If fuel economy is still around 11L/100kms I'll slide the EGR blank out for the return trip and directly compare. Won't pull the throttle valve yet for two reasons 1. Don't know where it is 2. The scan gauge hasn't arrived yet
Do I need to block the one way valve in MAP line if I slide out the EGR blank for the return trip?
Ben
Users browsing this forum: No registered users and 18 guests