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Def is injected after the engine and into the exhaust. Hints diesel exhaust fluid. It will in no fashion affect fuel economy. What will affect fuel economy is and not limited to. Fuel quality, your foot, air temp, engine temp, stop and go vs highway driving, If your in a regen.. that’s a big one… how loaded you have the car, dirty air filter, oil weight, tire pressure but def does not help propel the vehicle in any fashion so it can not help or hurt mpg. Plus. The tank last right at 10k miles. Who here keeps up with a 10k avg mpg? And rests every full up and tries something different? Please don’t spread bad info. Check ISO 22241 and you will learn about def and how it works


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Indirectly I believe it may actually or more correctly stated, nox2 directly measures nox levels and allows for a more precise urea dosing control based on the conversion efficiency of the catalyst and this allows the engine to run leaner and achieve better fuel economy.

Def Platinum, who knows. But the scr system is designed to always maximize the conversion factor to meet emissions and burning less fuel ie: better mileage, is a part of it.
 

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Indirectly I believe it may actually or more correctly stated, nox2 directly measures nox levels and allows for a more precise urea dosing control based on the conversion efficiency of the catalyst and this allows the engine to run leaner and achieve better fuel economy.

Def Platinum, who knows. But the scr system is designed to always maximize the conversion factor to meet emissions and burning less fuel ie: better mileage, is a part of it.
There is no fuel trim feedback from the nox sensors. The closest your gonna get is if it seeing the egr is needed more to meet emissions and that harms economy. But still. Def fluid is not going to help economy . That’s in your driving habits and the driving conditions at that given time. Def is 100% an after thought to fix the problem. If you have a scanner you can watch the nox drop with egr. Egr works great at lowering combustion temps to lower nox but it’s not perfect by any means. We all know egr downside. def is there only to scrub what the egr couldn’t prevent in the first place. Now it does work the other way around. You are heavy footed and the def system is working harder to keep nox to a min and you will consume more def. But buying a “premium” def will do you no better than that off brand so long as it meets the iso 22241. Here is some more info



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There is no fuel trim feedback from the nox sensors. The closest your gonna get is if it seeing the egr is needed more to meet emissions and that harms economy. But still. Def fluid is not going to help economy . That’s in your driving habits and the driving conditions at that given time. Def is 100% an after thought to fix the problem. If you have a scanner you can watch the nox drop with egr. Egr works great at lowering combustion temps to lower nox but it’s not perfect by any means. We all know egr downside. def is there only to scrub what the egr couldn’t prevent in the first place. Now it does work the other way around. You are heavy footed and the def system is working harder to keep nox to a min and you will consume more def. But buying a “premium” def will do you no better than that off brand so long as it meets the iso 22241. Here is some more info



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Interesting.

I'll agree to disagree, to a point.

A properly working SCR will allow minimum exhaust and provide maximum fuel efficiency. Any one part of the system will effect both.

The systems effectiveness allows diesel engines to be tuned and optimized toward maximum fuel efficiency, while the SCR systems are highly efficient at treating the engine-out exhaust.

The SCR system uses an daptive strategy similar to long-term fuel trim (LTFT) and is used to determine the duty cycle that the DEF injector should be operated at. Since there are numerous variables that can affect the amount of DEF that is injected for a given duty cycle, the table is always being rewritten to maximize NOx conversion efficiency thus maximizing fuel economy.

I agree 100% on the platinum but if they indeed state increased fuel economy then they would be liable if it didn't deliver and I'd be surprised if any certifying agency would put their name on it.

EGR, ugh.
 

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Interesting.

I'll agree to disagree, to a point.

A properly working SCR will allow minimum exhaust and provide maximum fuel efficiency. Any one part of the system will effect both.

The systems effectiveness allows diesel engines to be tuned and optimized toward maximum fuel efficiency, while the SCR systems are highly efficient at treating the engine-out exhaust.

The SCR system uses an daptive strategy similar to long-term fuel trim (LTFT) and is used to determine the duty cycle that the DEF injector should be operated at. Since there are numerous variables that can affect the amount of DEF that is injected for a given duty cycle, the table is always being rewritten to maximize NOx conversion efficiency thus maximizing fuel economy.

I agree 100% on the platinum but if they indeed state increased fuel economy then they would be liable if it didn't deliver and I'd be surprised if any certifying agency would put their name on it.

EGR, ugh.
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Read the advertisement again.

It doesn't say that it will increase fuel economy.

It states that it will prevent a decrease in fuel economy. There is a difference.

This is done by keeping the scr cat cleaner and not becoming clogged.

This can happen on short trips where the scr cat doesn't get up to a good temp. Thr Def will crystallize and clog thr scr cat.

Note that this is much more likely happen in a Diesel passenger car vs a big rig kenworth. It happened to my Diesel cruze...

Jeff
 

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Read the advertisement again.

It doesn't say that it will increase fuel economy.

It states that it will prevent a decrease in fuel economy. There is a difference.

This is done by keeping the scr cat cleaner and not becoming clogged.

This can happen on short trips where the scr cat doesn't get up to a good temp. Thr Def will crystallize and clog thr scr cat.

Note that this is much more likely happen in a Diesel passenger car vs a big rig kenworth. It happened to my Diesel cruze...

Jeff
Now that makes more sense. I was not going to argue any more about it. Yes. That is not an issue on Class 8 but they do over dose for one reason or another. I did have a hung open doser and it filled a Decomposition pipe lol. What a mess…. Def is water soluble and if crafty, you can remove the scr and simply was it out. I don’t have that issue with mine bc I drive 55 miles one way to work and it’s all 65+ for 50 of it.

P.s. thanks for clarifying my miss understanding.


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