how did 2004.5+ meet emissions w/o EGR?

[NPauli]

So I'm new here, shopping for my first diesel, and eyeing a 5. 9 Mega Cab. I start doing my homework, and am surprised to learn that there's no apparent EGR system (no plumbing, no cooler, no valve) on the engine to help meet 2004 EPA emissions.



BUT...



I worked in CAT engine development from ~ 2004-2007, and distinctly remember some competitive engine tear-downs and some "yeah Cat, boo Cummins" marketing stuff coming out showing all the nasty soot deposits left by our competitors' EGR systems.



On to the questions...



Did Cummins do internal EGR for 2004 emissions? By internal EGR, I mean messing with the valve timing so that more of the exhaust stays in the cylinder.



On a related note, does anyone have a feel for which would be worse for fuel economy, durability, oil life, etc. : internal EGR or external cooled EGR (what DMAX and International did).

 

[jelag]

The Cummins engine as it was built in those years was clean enough to work without the EGR system... remember that EGR is to reduce NOX.....

EGR was a system designed to allow some of the exhaust gas to go back to the combustion chamber... in doing so... the exhaust gas would take up space in the combustion chamber... . this would lower combustion chamber temperatures by there being a smaller amount of air/fuel in the combustion chamber... .

Before EGR there was 100% air/fuel to burn... with EGR say there is 85% air/fuel and 15% inert gas (exhaust)... because of the smaller charge in the same space a smaller combustion would occur and thus less heat... .

On an engine working hard... close to WOT (wide open throttle) the exhaust gas contains too much heat for EGR to function... the heat would turn the engine parts that handle the gas red hot... which would cause failure of those parts... EGR coolers were designed to lower the gas temperature... .

When EGR is designed correctly and functioning as it should it doesn't lower mpg and can contribute to engine life... because when it's working there is smaller combustion and less shock on the engine...

The same process could be obtained by caring a bottle of inert gas on the frame of the truck and injecting it at the correct time... . the problem than is the extra weight from the cylinder and to cost to fill the cylinder when it was empty. .

 

[mattymac]

third inj event, better flowing head, cat, cam timing (I think) im sure theres some others but those are a few of the biggies

 

[JasonCzerak]

Mine won't pass emissions anymore. the little puff at startup and haze won't qualify anymore...



:-laf:-laf:-laf



But yeah. the Cummins motor didn't need EGR or VG turbo for all 5. 9 motors to keep compliance (this is up to 07). 07. 5 is a different story.

 

[steved]

Actually, from another thread on this forum, our trucks are EGR engines... the 600 just did the dirty work inside the head without the need for a separate EGR valve.

You don't need an EGR valve to be and EGR engine.

 

[cerberusiam]

Did Cummins do internal EGR for 2004 emissions? By internal EGR, I mean messing with the valve timing so that more of the exhaust stays in the cylinder.

Yes they did. Valve timing, third injection event, and a small turbo hot side housing, and programming all contributed to make what Cummins billed as "in-cylinder EGR solution". Starting with the 600 series engines in 04. 5 they all had the same setup. The earlier CR's with 2 events had retard valve timing and injection timing and some of the same overlap but no where near as aggressive as the later engines.



As for durability, any time you introduce particulates back into the engine and restrict the complete combustion of the fuel mixture, which is what is happening, you impact oil life and to an extent engine life. The trade off is cooler combustion temps which will add to engine life. Its a trade off on several different levels.

 

[JasonCzerak]

Actually, from another thread on this forum, our trucks are EGR engines... the 600 just did the dirty work inside the head without the need for a separate EGR valve.



You don't need an EGR valve to be and EGR engine.

Please explain. diagrams would be nice.

 

[steved]

Yes they did. Valve timing, third injection event, and a small turbo hot side housing, and programming all contributed to make what Cummins billed as "in-cylinder EGR solution". Starting with the 600 series engines in 04. 5 they all had the same setup. The earlier CR's with 2 events had retard valve timing and injection timing and some of the same overlap but no where near as aggressive as the later engines.

Please explain. diagrams would be nice.

I think he just did???

 

[JasonCzerak]

I think he just did???

ohh ok. I over looked that one and it didn't click. . That's what I though. for some reason I though he was saying there are some valve and loops and what not with in the head to recirculate.

 

[steved]

ohh ok. I over looked that one and it didn't click. . That's what I though. for some reason I though he was saying there are some valve and loops and what not with in the head to recirculate.

It is a "perceived" EGR system... basically it burns everything in the exhaust using the 3rd injection event for added fuel.

 

[KHelfrich]

I talked to a guy at cummins when I was interviewing for a job there and asked him about the cummins 600 cause that is whats in my dad's truck and why the fuel milage sucks. this guy was an engineere that was in on the launch of the 600 and of the new 6. 7 he told me that what they did to lower the NOx was a different injector spray and piston dish along with different programing. he told me to get good milage all I would have to do is change the injectors and pistons to ones from the 305/555 engine and the the ecm from a 305/555 motor and the latest progam would have the best fuel economy

 

[p-Bar]

It is a "perceived" EGR system... basically it burns everything in the exhaust using the 3rd injection event for added fuel.

the third event keeps the Cat hot so it can do it's job

 

[KHelfrich]

from what the guy at Cummins told me the third event does not happen very often. I thought that was what killed the fuel economy but he said it rarely fires the third spray

 

[CKelley1]

ok here is what you have to do to correct most of the in cylinder egr, first you have to correct the timing, the best and cheapest way is to get a smarty jr with 4. 0 software and set it on tow, next and not so cheap is to change the cam to a pdr cam next a turbo back exhaust and last a cfm+ and grid heater delete, the smarty advances all three pulses the same amount wich helps a lot on the third pulse but not enough to get all of what could be. every time i get a chance to talk with one of the venders about soft ware change to do this i am told they are spending more time on the 6. 7 and that is on the back burner . the mods i mentioned will lower egt by about 100* and increase mpg by four miles per gallon, it also makes for a smooth torque curve

 

[AH64ID]

Like most have said, yes it adjusts the valve timing for EGR. . The 3rd injection event is not a constant event and it also is part power and part emissions. In addition to this the injection timing has been retarded, which may reduce combustion temps and cylinder pressure. . but it really reduces power and increases EGT's...

If someone where to "export" there truck and not want the emissions anymore the best thing to do would be to advance the timing, I recommend Smarty Jr, ditch the kitty, and put a PDR or Helix Cam in. Those things would increase power, mileage, oil life, and decrease EGT's.

 

[WCounts]

I don't believe the 04. 5-07 cr has any kind of egr. Cummins states egr was not used in these engines. They used a ecm controlled waste gate turbo with a very small turbine housing that spools quickly when needed. These are some of the quickest spooling turbos. Also the ecm is programed to limit fueling by ramping along with boost. This along with the big cat allowed the Cummins to pass emissions at that time. The thing I hated the most about my 04. 5 was the built in lag. Smarty does a good job of taking care of this allong with a few other things. There are a few new 07 5. 9s still on the dealers lots but they don't have the rebates the 08s have.

 

[CKelley1]

the 04. 5 to 07. 5 does indeed have in cylinder egr

. check with cummins they have a long article describing how it works and this is what causes the black oil also

 

[WCounts]

The only way to have egr is exhaust gasses have to find there way back into the cylinder. On a turbo charged engine the only way would be to route some exhaust gasses into the intake side. With the intake pressurized there's no way for the exhaust gasses to be sucked in from the exhaust side. During valve overlap the manifold pressure will evacuate the exhaust gasses.

Billy

 

[cerberusiam]

The only way to have egr is exhaust gasses have to find there way back into the cylinder. On a turbo charged engine the only way would be to route some exhaust gasses into the intake side. With the intake pressurized there's no way for the exhaust gasses to be sucked in from the exhaust side. During valve overlap the manifold pressure will evacuate the exhaust gasses.

Billy

Your complicating things way too much, the simplest way to do EGR is just not evacuate all the combustion charge on the exhaust stroke. Engine manufactures have been doing this for 30 years.



Its even easier with a turbo charged engine as you can somewhat control the amount of oxygen depleted charge that is reatained by adjusting the exhaust valve opening and overlap, and, the amount of back pressure created by the turbo. Keep in mind the boost to drive pressure ratio runs about 1:1. 2 all the time and will peak at 1:2 when the 3rd event is triggered.



With this design the valve overlap never fully scavneges the cylinder on intake and the amount of exchange decreases as the drive pressure increases. Simple, cheap, effective.



FYI, Cummins calls it "in-cylinder EGR" in all their documentation, so yes Cummins acknowledges the 600 series engines have EGR. Even the 03-04 engines have somewhat the same setup with overlap, delayed timing, and drive pressure but it was enhanced with the 3rd event and the valve timing for the later engines to meet EPA and CARB requirements.

 

[WCounts]

So I guess when you install a after market turbo with a less restrictive turbine housing you reduce egr to a degree. Any engine will have some exhaust gasses left in the cylinder. It's just imposible to get all exhaust gasses out. So all engines have some amount of egr.

Billy