The whole EGR "business"

Before electronic engines the pyro was an essential gauge in the NA truck that you watched religiously. However you are still wrong about EGR and EGT. Even the dang wikipedia article contradicts you.

 

Show me the wiki link. Propably some "internet expert" wrote it. I read real books.

 

I think he's talking about the link I posted at the top of the thread. I don't have a dog in this temperature stuff, because I don't have a clue, but I think a pyrometer is still a pretty normal factory gauge over here. Might not be totally necessary, but it sure makes it easier to see when you've got a CAC or boot starting to leak.

 

It's correct except the "EGR increases the amount of PM that must be dealt with and reduces the exhaust gas temperatures". "Reduces exhaust gas temperatures" is wrong especially when they earlier said "Particulate matter (mainly carbon) that is not burned in the power stroke is wasted energy." That wasted energy makes higher EGTs.

 

Pyro gauges are not standard. About all you have not is the high exhaust temp lamp for DPF equipped trucks.

But Lenny you are applying petrol concepts to a diesel engine and you just can't do that. Many many changes were made on euro engines to raise engine temperatures to improve thermal efficiency with SCR equipped trucks. It sounds like you have experience with an EGR truck... Which for europe puts you in one of the trucks that do not use SCR. But you higher exhaust temps are not from EGR (you also mentioned retarded timing which would not increase exhaust temperatures). The statement wasted energy makes higher exhaust temperatures makes absolutely no sense., if you don't have a catalyst converting soot to heat (DOC-the first stage of a DPF)

 

Many many changes were made on euro engines to raise engine temperatures to improve thermal efficiency with SCR equipped trucks.

Engine temperature and combustion temperature are not same as exhaust gas temperature.

you also mentioned retarded timing which would not increase exhaust temperatures

Try to ###### timing and watch your EGTs rise.

The statement wasted energy makes higher exhaust temperatures makes absolutely no sense.

Where is the energy going? Soot means uncomplete burn, it still burns when exhaust valve opens. Burning in exhaust ports and manifold raises EGTs. Soot can also mean not enough air, excess air cools EGTs.

 

egr systems get clogged up . thers nothing inherently wrong with egr, its the specific system that gets carboned up or has problems heating the fuel or bypass fuel too much, some tard with a bs in engineering and a 3 piece suit designs a system with these little 1/4" passages, lol and then at 300,000 miles your systems plugged up , or they use bypass fuel for cooling so if you have 30 gallons in you tank you fuel ends up at 200 degrees. thers nothign wrong with emissions equipment , the ######### just take a car systemn that runs 30 miles to the store and copy it for atruck thats expected to go 600,000 miles with only oil + filters.

 

EGR coolers on trucks use engine coolant not fuel. Also they are not tiny little 1/4" passages.

Don't compare automotive technology to heavy duty trucks, the scale is quite a bit different.

 

Brian, you don't seem to understand what makes a diesel sound like a diesel.
The distinctive "diesel" sound that you believe is an explosion can be toned down to utter silence just by changing the injector pulse from a single pulse to a multi-pulse per cycle event. It isn't the type of fuel, but rather it's archaic dispursement. Have a listen to the new Paccar MX, or better yet, the new 2011 Ford Powerstroke diesel. They are almost totally silent. You will find in the very near future that injector technology will have all diesel engines running as quiet and a Honda Accord.
Also, there is no "reaction" in the DPF. It isn't a catalyst, but merely a substrate filter element that is periodically cleaned by added fuel and raising the EGTs.

There is no need to go into a disection of the EGR process, other than to try to explain a very complex way of administering a crude and archaic ############ that is easily understood by someone who doesn't know.
Thank God SCR is now used in America.

 

Actually I do but I wasn't going to go into the complexities of explaining exactly why it is that a diesel cycle doesn't have the wavefront requirements that a spark ignition engine requires in order to run efficiently. It easier to explain as an explosion. And your right the fuel doesn't mater as you can run gasoline in a "diesel" cycle engine, but the compression has to be substantially lower (LNG/CNG/etc).

As for the DPF. There is in fact a catalyst inside a DPF. Sometimes it is two discreet entities but most often it is just noble metals plated to the DPF substrate. When you catastrophically overheat the DPF you will get platinum and palladium either dripping from the bottom or shooting out the pipe in weed burners. Oxidation is a reaction, by adding a catalyst the reaction can happen at a lower temperature allowing for things such as passive regenerations.