commtrd

I understand that as part of an on-going effort to reduce exhaust emissions on the 2004 model year trucks with Cummins engines that they will employ exhaust gas recirculation as well as a variable ratio turbocharger. <br><br>Does anyone know how the EGR will return exhaust gasses to the engine? I am just about ready to order a truck and the salesman from Mark Roberts said that around the end of June was the last time to get a '03 ordered and after that it will be a '04 model. I read somewhere (Cummins website I think) that they were going to use EGR on the '04 engine and I don't want that. <br><br>Are there any dealers (Luke?) that may know more about this issue? I think that EGR on a diesel engine could be a real problem; depending on how it is done.

spots

Do a search on EGR on this site and you will find, I believe, that the 2004 will not have EGR before Jan 1, 2004. Basically a valve will be used to introduce inert (exhaust) back into the combustion chambers to reduce temp therefore reduce NOx. I don't know about the turbo tho. HTH<br>Also was a thread here about the misinformation about the EGR engines and Cummins on the larger engines gave a rental if they could not fix the engine in a timely manner

TON4FUN

I don't see what the big deal is about the EGR system. Every car on the street today has one. I took the EGR system off my car and it actually lowered my EGT's by about 50 degrees. Keep in mind my car is not a street car but a track only car. <br><br>What I'm wondering is if they will have to put on a vacuum pump to opererate the EGR valve and if the intake manifold is being redesigned.

commtrd

Well reducing EGT's is a good thing I reckon...but what I was concerned about is introducing exhaust gasses back into the engine and how that gets done. If it is cooled first that means the possibility of the intercooler getting plugged up with soot and carbon and the addition of extra plumbing to facilitate the gasses getting back into the engine. Also exactly where the exhaust gas is put back into the engine could be a problem. If the benefit is to be gained from cooling the mixture inside the combustion chamber to lower NOx emissions then why not just focus on greater intercooler delta T efficiency? <br><br>I guess I do not understand all there is to know about diesel engine efficiency since I am not an engineer...but there seems to be opposing ideas at work here. For example, the diesel is a compression ignition air pump. So cooling the air prior to ignition would seem to run counter to the idea of increasing the charge of air via turbocharger. I searched on the cummins website and found a deal where they showed the variable-ratio turbocharger and a short dissertation on the EGR approach to reduction of NOx emissions. They claim to have met the EPA regs on NOx emissions as of the 2002 model year on the ISB, ISX, and the ISM engines were the last to be certified in compliance by the Oct 2002 deadline. <br><br>Maybe this issue is of no concern...I just think there may be a better way than putting dirty exhaust gas back into the engine. Any comments from more knowledgeable out there?

spots

EGR gases are usually not cooled first before being introduced to the intake manifold. I don't believe you would see any outside plumbing. Most passages would be within the cyl heads and intake manifold. You might ask an engineeer about the Delta T thing you mentioned. I didn't design the engines just worked on them.<br>To answer another question: Cooler air is denser air-denser air has more oxygen in it (needed for combustion) More air plus more fuel equals more power per cubic inch or more HP/Torque for the displacement of the engine. Air is composed of 20% Oxygen, 78% Nitrogen and if I recall correctly 2% &quot;other&quot;. <br>Composition of the Atmosphere<br>Adapted from http://ess.geology.ufl.edu/ess/Notes...atmoscomp.html <br> <br>Constituent Chemical <br>Formula Molecular<br>weight Percentage of this <br>constituent in the <br>atmosphere, by volume Total mass of this <br>constituent in the whole <br>atmosphere (grams) <br>Nitrogen N2<br> 28.0134<br> 78.084 %<br> 3.866 * 1021<br> <br>Oxygen O2<br> 31.9988<br> 20.948 %<br> 1.185 * 1021<br> <br>Argon Ar<br> 39.948<br> 0.934 %<br> 6.59 * 1019<br> <br>Carbon dioxide CO2<br> 44.00995<br> 0.0315 % <br> 2.45 * 1018<br> <br>Neon Ne<br> 20.183<br> 0.001818 %<br> 6.48 * 1016<br> <br>Helium He<br> 4.0026<br> 0.000524 %<br> 3.71 * 1015<br> <br>Methane CH4<br> 16.04303<br> 0.00015 %<br> 4.3 x 1015<br> <br>Hydrogen H2<br> 2.01594<br> 0.00005 %<br> 1.8 * 1014<br> <br>Nitrous oxide N2O<br> 44.0128<br> 0.00003 %<br> 2.3 * 1015<br> <br>Carbon monoxide CO<br> 28.0106<br> 0.000012 %<br> 5.9 * 1014<br> <br>Ammonia NH3<br> 17.0306<br> 0.000001 %<br> 3 x 1013<br> <br>Nitrogen dioxide NO2<br> 46.0055<br> 0.0000001 %<br> 8.1 * 1012<br> <br>Sulfur dioxide SO2<br> 64.063<br> 0.00000002 %<br> 2.3 * 1012<br> <br>Hydrogen sulfide H2S<br> 34.080<br> 0.00000002 %<br> 1.2 * 1012<br> <br>Ozone O3<br> 47.9982<br> ~ 0.00004 % (variable)<br> ~3.3 * 1015<br> <br>Water vapor H2O<br> 18.01534<br> ~ 0.5 % (variable)<br> ~0.017 * 1021<br> <br>Total atmosphere - 28.9644 (average) - 5.136 x 1021 <br><br><br>http://othello.mech.nwu.edu/~peshkin...tmosphere.html<br><br>I think the EGR will be a non issue. VW has had a TDI with EGR for some time, and yes there have been some problems with it. Some owners disconnect the EGR. Diesel exhaust is &quot;dirtier&quot; than gasoline exhaust and this is the problem some have with EGR. Hope that clairfys some for you.

cp

EGR on diesels has been around for a while. I have an '84 300D Mercedes that has it.

From an environmental point of view, I guess it's a good thing. From an engine cleanliness standpoint, it's undesirable. It makes a mess in the intake manifold.