Gas or Diesel ?

[TC]

It's a measure of the particulates (black stuff) that are coming out of the tail pipe. Even when you can't see it a calibrated light or laser can measure the particulates and check the opacity of the exhaust. With the new'ish NOx controls, it won't be long before places like CA start measuring NOx on diesels like they do cars, if they don't already.

I went through emissions with a diesel VW Rabbit that I used to own, the thing was just pumping out smoke like nobodies business, the guy at the test station thought for sure I was going to fail, but when the results came in it has 0 Opacity........ Funny thing is I had just been in there 20 minutes before and failed miserably, I just ran back to the shop, adjusted the fuel delivery on the injection pump and ran back and had it tested...... So much for the Emission Station's advice to take it to a diesel mechanic.....

[TheSilverBuick]

Dan can you explain what Opacity is??, that is what the Emissions people here test Diesel for........

It's a measure of the particulates (black stuff) that are coming out of the tail pipe. Even when you can't see it a calibrated light or laser can measure the particulates and check the opacity of the exhaust. With the new'ish NOx controls, it won't be long before places like CA start measuring NOx on diesels like they do cars, if they don't already.

[TC]

if I was just a customer ...I would buy a d max ....but they are more trouble than gas engines and everything costs a lot more

thanks to the nanny state ...there are no gas big blocks

This statement is somewhat BS, I have an '06 Duramax, have had no problems at all with it....... LBZ baby!!!!......

[TC]

Joe's got it. The urea goes thru the NoX adsorber and causes a catalytic reaction so what leaves the adsorber has nothing to do with the urea (or Diesel fuel) that went in. The whole point of the NoX regeneration is to turn whatever is on the surface of the adsorber into benign components (N2 and H2O). This clears off the surface of the adsorber so it can grab whatever comes down the pipe next.

A bit of Diesel education. Compared to an Otto-cycle engine, Diesels make little unburned HC and not much CO and they can be eliminated with a fairly conventional catalyst. The particulate matter can be cleaned up easily with a Diesel particulate filter (DPF) - these have been in use for many years and you've seen them at an indoor tractor pull on the tractor that pulls back the sled (otherwise the arena gets filled with smoke). The cat and the DPF can easily be combined and in fact they work better when they are.

NoX is made in large quantities in a Diesel and it's the hard one to reduce. NoX is generated as a result of high combustion chamber temps, pressure, and time. Diesels have lots of temp and pressure and relatively lots of time given the slow engine RPMs so they make lots of NoX. EGR helps, especially when it's cooled. But to get it to "safe" levels (always an argument about what's "safe") requires some sort of aftertreatment. Diesel NoX does not catalyze (that is, convert to benign substances when exposed to certain noble metals - I don't know why Otto cycle NoX does and Diesel NoX doesn't) so the best way to handle it (given current technology) is to hold it and regenerate the holding medium. The best technology available today is the adsorber - an aBsorber holds the controlled substance in the pores of the substrate while and aDsorber holds it on the surface. Anyhow, it has to be cleaned off with catalytic action and that can be triggered with either Diesel fuel or urea.

There - wasn't that simple!? I spent WAY too many years of my life messing with this stuff.

Dan

Dan can you explain what Opacity is??, that is what the Emissions people here test Diesel for........

[milner351]

Jim - GM killed the 8.1? I thought you could still get that in the over 8500gvw stuff?

The Ford V10 lives on - but only in the Econoline heavies.

[SpiderGearsMan]

if I was just a customer ...I would buy a d max ....but they are more trouble than gas engines and everything costs a lot more

thanks to the nanny state ...there are no gas big blocks

[SpiderGearsMan]

they took compression out for less noise ....but the engineers raised the boost

[Deaf Bob]

Thanks Joe and Dan.. Makes sense now..

[DanStokes]

Finally, the urea (35% in deionized water) reacts with the NOx in the exhaust to cause a chemical reaction to produce Nitrogen and and H2O. Saying it's cow piss in the tank is like saying you wrap your sandwich in crude oil because you use plastic wrap.

Joe's got it. The urea goes thru the NoX adsorber and causes a catalytic reaction so what leaves the adsorber has nothing to do with the urea (or Diesel fuel) that went in. The whole point of the NoX regeneration is to turn whatever is on the surface of the adsorber into benign components (N2 and H2O). This clears off the surface of the adsorber so it can grab whatever comes down the pipe next.

A bit of Diesel education. Compared to an Otto-cycle engine, Diesels make little unburned HC and not much CO and they can be eliminated with a fairly conventional catalyst. The particulate matter can be cleaned up easily with a Diesel particulate filter (DPF) - these have been in use for many years and you've seen them at an indoor tractor pull on the tractor that pulls back the sled (otherwise the arena gets filled with smoke). The cat and the DPF can easily be combined and in fact they work better when they are.

NoX is made in large quantities in a Diesel and it's the hard one to reduce. NoX is generated as a result of high combustion chamber temps, pressure, and time. Diesels have lots of temp and pressure and relatively lots of time given the slow engine RPMs so they make lots of NoX. EGR helps, especially when it's cooled. But to get it to "safe" levels (always an argument about what's "safe") requires some sort of aftertreatment. Diesel NoX does not catalyze (that is, convert to benign substances when exposed to certain noble metals - I don't know why Otto cycle NoX does and Diesel NoX doesn't) so the best way to handle it (given current technology) is to hold it and regenerate the holding medium. The best technology available today is the adsorber - an aBsorber holds the controlled substance in the pores of the substrate while and aDsorber holds it on the surface. Anyhow, it has to be cleaned off with catalytic action and that can be triggered with either Diesel fuel or urea.

There - wasn't that simple!? I spent WAY too many years of my life messing with this stuff.

Dan

[SuperBuickGuy]

Was one better than the other (6.2 6.5) ? The truck has a new 6.5 in it,the body only has about 40k on it. The PO was a GM mechanic and did the swap.

not really

[joebogey]

Dan- I haven't read up on the source for the Cruze just yet, but it's not offered in a long roof. The longroof Jetta comes in fully loaded under $30k, not sure what your budget is.

As for the CSI, seems unless it was branded Honda or Toyota it never did so well. Just in my immediate family we've had '84 Rabbit diesel (265k miles & counting), '85 Golf diesel (retired with 160k miles after an accident), '86 Golf diesel (140k miles & counting), '88 Jetta gas (95k totaled in an accident), '89 Jetta diesel (130k miles and counting), '95 Jetta gas (145k miles and counting), and '13 Beelte diesel (just a baby). Then there's the half dozen or more between extended family and friends. If maintained properly, haven't had a issue.

Finally, the urea (35% in deionized water) reacts with the NOx in the exhaust to cause a chemical reaction to produce Nitrogen and and H2O. Saying it's cow piss in the tank is like saying you wrap your sandwich in crude oil because you use plastic wrap.

[TheSilverBuick]

Damn, we should get cats, birds, dogs, deer, cows, horses, etc etc etc etc to stop pissing into the wind.

[moparmaniac07]

Ok how about: why is urine injected into the engine/exhaust?
Why not WATER? or water/alky?

Water won't react chemically with the whatever exhaust particle the EPA is currently focused on.

[moparmaniac07]

Mazda is bringing out a "low compression" (14:1) Diesel sedan (626/mazda6) later this year - no exhaust aftertreatment whatsoever, and no DEF

I'm betting the aftermarket will soon have "DEF Delete kits" for "off road use only" if they don't already.

Didn't read anything after this yet, but there already are "DEF delete" programs. One of the programmer companies is getting fined or sued by the EPA for it. I want to say Edge, but I don't think that's it.

Wouldn't a lower CR lower fuel economy as well? Just to get lower PPM per gallon, but use more gallons to do it, in turn spewing out more particulate matter.

[TC]

Ok how about: why is urine injected into the engine/exhaust?
Why not WATER? or water/alky?

Bob it's not injected into the motor it is injected after the motor into the exhaust system, where combustion is not really going on, which makes one wonder how much of the Urine is burnt off and how much makes it into the atmosphere for us to breath......