circular base flange at end of exhaust?

Nero

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Alright, I'm laying on my favorite couch, and full off of Costco pizza, so it's time to type this out.

So for diesels, emissions started being mandated by the epa in 2002 to reduce NOx, which stands for nitrogen oxide, which is by definition, gases-nitric oxide (NO), which is a colourless, odourless gas and nitrogen dioxide (NO2), which is a reddish-brown gas with a pungent odour.

NOx is bad, because even in small quantities, it is harmful to your upper respiratory tract and can lead to asthma and other lung diseases. It also attaches to Ozone molecules, thus breaking it down even further.

So in 2002 for diesels to reduce NOx, they introduced Exhaust Gas Recirculation (EGR) which introduces inert gasses to the combustion cycle, which in turn lowers combustion temperatures, which lowered NOx. Took care of a majority of it and it ran that way until 2007. It is designed that EGR only operates typically under motoring, cruising, or idling conditions. Power demand like accelerating or pulling loads, it's supposed to be closed. So the old rumor of 'it lowers power output' is for the most part a half cop out from those who don't understand it.

In 2007 the EPA, being the big brother they are, said NO MORE BLACK SMOKE. So thus the Diesel Particulate Filter (DPF) Was designed. It works in conjunction with the Diesel Oxydation Catalyst (DOC) which is essentially a giant catalytic converter right before the DPF.
This device does have the potential to reduce fuel economy, and in more cases than not, does. The DPF and DOC work by all of the airborne soot particles coming out of the exhaust are caught in the DPF. The DPF is essentially a wall flow-through trap design of ceramic material. Think of a catalytic converter, except it looks like a checker board. Each pinhole is a soot trap.

So what happens when it gets full? That's when the engine has to do a regeneration. There's two kind of regens, passive and active. Passive occurs when the exhaust is able to get hot and maintain it's temperature based off of just it's operating condition. Driving for miles at a steady speed on the freeway is a good way to achieve this.
Active regeneration is when the engine computer has to take over and force hotter exhaust. How that work? Well, during the exhaust stroke, raw fuel is injected into the exhaust stream, either via the fuel injectors, or an extra fuel injector that exists just after the turbo before the down pipe.

This raw fuel goes through the DOC, which creates a chemical reaction called Plasma gasification, where the exhaust jumps up from about 600-700F, to anywhere between 1100-1300F. This hot exhaust literally bakes the soot caught in the DPF until it cooks it down to ash and releases gasses. I forget what gasses it releases. I think it's oxygen and nitrogen molecules.

Early in it's developments, DPF and regen systems sucked butt. They did slowly get better over the years, and not rarely have issues. As long as you don't idle your truck. Seriously, even without emission controlled engines, idle is the killer of engines.

So anyways, it ran this way until EPA was like oh hey these guys let's mess with them and make things more strict. So in 2010 diesels had to lower their NOx even more, because EGR just wasn't cutting it. Thus came along the Selective Catalyst Reductor (SCR) system and everyone's favorite, diesel exhaust fluid (DEF)

So these are actually a little neat to me, just because of the science that went into it. So the DEF is injected into the exhaust stream right after the DPF into a swirling type device to really mix it up, then it enters the SCR, where the vaporized Def fluid reacts with the SCR material and literally rips the molecules of NOx apart, until you have individual nitrogen molecules, and oxygen molecules. They also have NOx sensors at the turbo outlet and SCR outlet, to determine the efficiency of them.

Sure, over the years they've had their own fair share of issues, leaky lines, quality sensor issues, all sorts of stuff. But as things progress, they've gotten way better as well. I now see trucks pushing 700k miles with all original emission parts on them. Sure, maybe a replacement sensor here or there but that's it.

Mind you, this is all industrial diesel stuff, not Ford or Chevy's stuff. And don't get me started with Cat, and how they decided they wanted to run a giant glow plug to get their super heat... Part of the reason they pulled out of the over the road market.

Anyways, my thumbs hurt. Time for a drink.
:cheers:
 

KansasIDI

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Alright, I'm laying on my favorite couch, and full off of Costco pizza, so it's time to type this out.

So for diesels, emissions started being mandated by the epa in 2002 to reduce NOx, which stands for nitrogen oxide, which is by definition, gases-nitric oxide (NO), which is a colourless, odourless gas and nitrogen dioxide (NO2), which is a reddish-brown gas with a pungent odour.

NOx is bad, because even in small quantities, it is harmful to your upper respiratory tract and can lead to asthma and other lung diseases. It also attaches to Ozone molecules, thus breaking it down even further.

So in 2002 for diesels to reduce NOx, they introduced Exhaust Gas Recirculation (EGR) which introduces inert gasses to the combustion cycle, which in turn lowers combustion temperatures, which lowered NOx. Took care of a majority of it and it ran that way until 2007. It is designed that EGR only operates typically under motoring, cruising, or idling conditions. Power demand like accelerating or pulling loads, it's supposed to be closed. So the old rumor of 'it lowers power output' is for the most part a half cop out from those who don't understand it.

In 2007 the EPA, being the big brother they are, said NO MORE BLACK SMOKE. So thus the Diesel Particulate Filter (DPF) Was designed. It works in conjunction with the Diesel Oxydation Catalyst (DOC) which is essentially a giant catalytic converter right before the DPF.
This device does have the potential to reduce fuel economy, and in more cases than not, does. The DPF and DOC work by all of the airborne soot particles coming out of the exhaust are caught in the DPF. The DPF is essentially a wall flow-through trap design of ceramic material. Think of a catalytic converter, except it looks like a checker board. Each pinhole is a soot trap.

So what happens when it gets full? That's when the engine has to do a regeneration. There's two kind of regens, passive and active. Passive occurs when the exhaust is able to get hot and maintain it's temperature based off of just it's operating condition. Driving for miles at a steady speed on the freeway is a good way to achieve this.
Active regeneration is when the engine computer has to take over and force hotter exhaust. How that work? Well, during the exhaust stroke, raw fuel is injected into the exhaust stream, either via the fuel injectors, or an extra fuel injector that exists just after the turbo before the down pipe.

This raw fuel goes through the DOC, which creates a chemical reaction called Plasma gasification, where the exhaust jumps up from about 600-700F, to anywhere between 1100-1300F. This hot exhaust literally bakes the soot caught in the DPF until it cooks it down to ash and releases gasses. I forget what gasses it releases. I think it's oxygen and nitrogen molecules.

Early in it's developments, DPF and regen systems sucked butt. They did slowly get better over the years, and not rarely have issues. As long as you don't idle your truck. Seriously, even without emission controlled engines, idle is the killer of engines.

So anyways, it ran this way until EPA was like oh hey these guys let's mess with them and make things more strict. So in 2010 diesels had to lower their NOx even more, because EGR just wasn't cutting it. Thus came along the Selective Catalyst Reductor (SCR) system and everyone's favorite, diesel exhaust fluid (DEF)

So these are actually a little neat to me, just because of the science that went into it. So the DEF is injected into the exhaust stream right after the DPF into a swirling type device to really mix it up, then it enters the SCR, where the vaporized Def fluid reacts with the SCR material and literally rips the molecules of NOx apart, until you have individual nitrogen molecules, and oxygen molecules. They also have NOx sensors at the turbo outlet and SCR outlet, to determine the efficiency of them.

Sure, over the years they've had their own fair share of issues, leaky lines, quality sensor issues, all sorts of stuff. But as things progress, they've gotten way better as well. I now see trucks pushing 700k miles with all original emission parts on them. Sure, maybe a replacement sensor here or there but that's it.

Mind you, this is all industrial diesel stuff, not Ford or Chevy's stuff. And don't get me started with Cat, and how they decided they wanted to run a giant glow plug to get their super heat... Part of the reason they pulled out of the over the road market.

Anyways, my thumbs hurt. Time for a drink.
:cheers:
Even our modern CAT equipment at my work throws emissions codes right and left. Terrible.

Our Peterbilt OTR trucks have emissions systems, one of them is temperamental, but the other 3 act fine. They are all X15 Cummins.

Our Dodge trucks are pretty good at eating DEF pumps, and clogging lines. They don’t seem to have much sensor problems with the DEF, but other electronics on the trucks frequently go Dodgy… lol
 

Nero

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See that's funny to me, cause Chrysler is the one that provides all the emissions stuff, minus the egr valve, on dodges.

Cat got out of the market because they want to engineer all their own stuff, and postponed it because off-road didn't require emissions... Until recently. Even large 50kw trailer generators have full emissions now. But they're all the very new stuff that runs well.
 

Jesus Freak

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DEF smells like a Tom cat got a hold of your truck. I'm all about my tom cats on the farm, but I really don't want to infuse them into my mechanicing.
 

KansasIDI

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See that's funny to me, cause Chrysler is the one that provides all the emissions stuff, minus the egr valve, on dodges.

Cat got out of the market because they want to engineer all their own stuff, and postponed it because off-road didn't require emissions... Until recently. Even large 50kw trailer generators have full emissions now. But they're all the very new stuff that runs well.
Runs good when it runs but breakdowns are super frequent with our newer CAT equipment. Talkin 2016-2023
 

KansasIDI

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DEF smells like a Tom cat got a hold of your truck. I'm all about my tom cats on the farm, but I really don't want to infuse them into my mechanicing.
That DEF is gross. Sticky smelly corrosive crap
 

IDIBRONCO

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DEF smells like a Tom cat got a hold of your truck. I'm all about my tom cats on the farm, but I really don't want to infuse them into my mechanicing.

That DEF is gross. Sticky smelly corrosive crap
I'll agree with both of these. The only time that I was behind several dump trucks that were burning it, my eyes burned and it took my breath away. That's the same effects of breathing in exhaust from a vehicle that's burning antifreeze. It's the reason why I call it poison. If it affects a person that way, it CAN'T be good to breathe.
 

KansasIDI

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I’d way rather breathe in diesel smoke. Especially from our IDIs, their exhaust gives off a scent that gives me
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Nero

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I'd rather breathe in none of them.
On another note, each diesel does smell different. I've noticed the 2008-2009 Cummins ism smells like off cinnamon to me.
 

KansasIDI

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I'd rather breathe in none of them.
On another note, each diesel does smell different. I've noticed the 2008-2009 Cummins ism smells like off cinnamon to me.
Yes I’m joking. But, these IDIs just have a certain smell… and I don’t mind it
 

chillman88

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The only smell I miss is the old gassers with no cats. One of the guys at work was warming up his old Harley and it brought back some good memories!
 

typ4

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You can thank the EPA , an agency that was implemented for industrial/ manufacturing emission control , for all of the vehicle problems. I was told they targeted the automotive/ consumer truck , Over the road theatre because they knew they could tax them to generate revenue.
Since the big industrialists could buy "credits" to pollute. AKA the clunker fiasco.
This info came from a reliable , as reliable as any gov emp could be .
Revenue that does nothing for emissions.
A messed up "clean air" vehicle pollutes more that any proper older one.
 

Nero

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That's fairly accurate.
You know who pollutes the most? Shipping boats and airplanes, by 30x as much as OTR trucks. But are we doing anything about those? Nope.
 

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