Managing EGR for MPG

[rh77]

Originally Posted by MetroMPG

Simplest (for testing) would be the exhaust tip at the back of the car, and a long *** hose back to the front

But make certain to let the neighbors know that you're not trying to commit suicide or else expect the whole brigade to show up.

RH77

[MetroMPG]

I was under the impression you couldn't really do that any more with a modern car in good condition. One of the ways of the 3-way catalyst is to rid the exhaust of the carbonium monoxodyl.

Still, the neighbours might not know this, so the brigade may show up anyway.

I wonder if they'd chase you down the highway while doing tests...

[rh77]

Originally Posted by MetroMPG

I wonder if they'd chase you down the highway while doing tests...

LOL...

I'm still pretty sure that the exhaust byproducts will bind to the body's Oxygen molecules and render the same effects...but I'll have to check on that...not with testing, that's for sure!

RH77

[rh77]

OK, the advent of the advanced CATs will slow the process, but there is always unburned fuel present which does it.

From the American College of Chest Physicians.

If inclosed in a garage, the o2 ratio will cause emission levels to increase because the car is using up the oxygen, so more fuel is added until it stalls -- by that time it's too late. If the car isn't breathing by that point, neither would the victim.

RH77

[Sludgy]

Originally Posted by MetroMPG

I was under the impression you couldn't really do that any more with a modern car in good condition. One of the ways of the 3-way catalyst is to rid the exhaust of the carbonium monoxodyl.

Of course, there is another insidious chemical in automobile exhaust: dihydrogen monoxide. Historically, more people have been killed by this chemical than any other. This is a FACT.

Where is EPA, NHTSA and OSHA on this issue?????

[rh77]

Originally Posted by Sludgy

Of course, there is another insidious chemical in automobile exhaust: dihydrogen monoxide. Historically, more people have been killed by this chemical than any other. This is a FACT.

Where is EPA, NHTSA and OSHA on this issue?????

OMG, I just looked it up -- it turns out that it's the main component in Cancer cells, people use it on their yards, and it's even been found in bottled drinks!



RH77

[omgwtfbyobbq]

MetroMPG, from what I've gathered, the appropriate amount of EGR reduces peak flame temperatures/NOx during combustion because it minimizes the amount of oxygen in the combustion chamber, but it has limits because if too much exhaust/heat goes back into the cylinder, the fuel will ignite on it's own after hot spots start to develop. So it's a fine line to walk so to speak, fuel with higher octane allows for more EGR, which reduces pumping losses by a proportional amount while resisting detonation that would happen if gasoline was used.

Originally Posted by Wikipedia

Reduced heat rejection. Lowered peak combustion temperatures not only reduces NOx formation, it also reduces the loss of thermal energy to combustion chamber surfaces, leaving more available for conversion to mechanical work during the expansion stroke.

[MetroMPG]

I wonder what makes higher cylinder temperatures: lean burn, or high rates of EGR.

[omgwtfbyobbq]

It probably depends in head/cylinder design. I've seen Honda mention swirl during lean burn so they don't get hot spots in the cylinder, and EGR may be able to have the same effect, but in either event, the limiting factor is how much heat can be released in the cylinder before the fuel starts detonating, which should be pretty lose wrt lean burn/EGR in any given engine design.

[rh77]

Originally Posted by omgwtfbyobbq

It probably depends in head/cylinder design. I've seen Honda mention swirl during lean burn so they don't get hot spots in the cylinder, and EGR may be able to have the same effect, but in either event, the limiting factor is how much heat can be released in the cylinder before the fuel starts detonating, which should be pretty lose wrt lean burn/EGR in any given engine design.

I'm thinking that the ignition timing will be retarded with the added heat -- and depending on if the vehicle has a knock sensor. If I understand correctly, if you use the proper fuel and introduce more EG, power will decrease, and FE increase? I'm guessing that the temp of the engine would continue to increase with the lean burn and require heavy-duty cooling.

RH77