How does regen work?
More Turbo
Joined: Nov 2005
Posts: 698
Likes: 4
From: Rural Northern California
Sure, I'll explain.
The goal of 'regeneration' is to burn off particulate matter trapped in the diesel particulate filter (DPF) of the exhaust system by using extreme heat.
Active Regeneration occurs when sensors before and after the DPF measure a buildup of particulates inside the filter matrix which are beginning to restrict exhaust flow. Once a threshold is reached, an active regeneration will commence by injecting diesel directly into the exhaust system.
The big difference between the Ford and the D-max is that Ford does not use the extra injector in the exhaust system. Instead, during the exhaust stroke of the engine (when the exhaust valves open to dump the burned combustion gasses down the exhaust pipe), extra fuel is injected and flows down the exhaust system. The fuel combusts either along the way to or at the DOC. The D-max injector is right before the DOC...so two ways of accomplishing the same thing. The DOC (diesel oxidation converter) is basically a catalytic converter for diesel engines which serves to increase heat.
The 2017 Ford, unfortunately, gives no warning or messages or indicators that an "active regeneration" is occurring. Previous generations would warn that an active regeneration had started, although they would never tell when one was completed.
Passive regen is the same as on a Duramax or Cummins. When towing a very heavy load, working the engine hard, exhaust gas temps may reach high enough temps to burn off particulates trapped in the DPF without injecting any additional diesel fuel. This is a natural process and requires no electronic intervention.
During and immediately after an active regen, the truck will smell like its on fire. A brand new truck experiencing its first few regens will smell worse than one that has already had 5 or 10 regens. It kind of breaks-in like the motor. Don't park on or near combustibles during or right after a regen.
Idle speed does not change during regeneration, but the engine has a slightly different tone if you listen for it. The turbo boost gauge becomes much more responsive during an active regeneration - more boost than usual is applied to help compensate for any power loss. Watching the gauge is one way to tell if a regen is occurring. Finally, fuel economy will drop considerably, as obviously extra fuel is being used.
Active regens will pause while stopped in traffic, and re-start automatically once you get moving above 4mph again.
Hopefully that helps.
The goal of 'regeneration' is to burn off particulate matter trapped in the diesel particulate filter (DPF) of the exhaust system by using extreme heat.
Active Regeneration occurs when sensors before and after the DPF measure a buildup of particulates inside the filter matrix which are beginning to restrict exhaust flow. Once a threshold is reached, an active regeneration will commence by injecting diesel directly into the exhaust system.
The big difference between the Ford and the D-max is that Ford does not use the extra injector in the exhaust system. Instead, during the exhaust stroke of the engine (when the exhaust valves open to dump the burned combustion gasses down the exhaust pipe), extra fuel is injected and flows down the exhaust system. The fuel combusts either along the way to or at the DOC. The D-max injector is right before the DOC...so two ways of accomplishing the same thing. The DOC (diesel oxidation converter) is basically a catalytic converter for diesel engines which serves to increase heat.
The 2017 Ford, unfortunately, gives no warning or messages or indicators that an "active regeneration" is occurring. Previous generations would warn that an active regeneration had started, although they would never tell when one was completed.
Passive regen is the same as on a Duramax or Cummins. When towing a very heavy load, working the engine hard, exhaust gas temps may reach high enough temps to burn off particulates trapped in the DPF without injecting any additional diesel fuel. This is a natural process and requires no electronic intervention.
During and immediately after an active regen, the truck will smell like its on fire. A brand new truck experiencing its first few regens will smell worse than one that has already had 5 or 10 regens. It kind of breaks-in like the motor. Don't park on or near combustibles during or right after a regen.
Idle speed does not change during regeneration, but the engine has a slightly different tone if you listen for it. The turbo boost gauge becomes much more responsive during an active regeneration - more boost than usual is applied to help compensate for any power loss. Watching the gauge is one way to tell if a regen is occurring. Finally, fuel economy will drop considerably, as obviously extra fuel is being used.
Active regens will pause while stopped in traffic, and re-start automatically once you get moving above 4mph again.
Hopefully that helps.
I appreciate your taking the time to write this up, an excellent explanation of where we are today with regeneration and how DEF is used to reduce NOx emissions.
A couple of additional questions...
1. Is the pressure differential pre and post particulate filter the only stimulus for regen or are there other factors (like timers or amount of fuel consumption) that can initiate the regen cycle in the 6.7 Ford?
2. Is any form of exhaust gas recirculation (EGR) used in the Ford 6.7 to reduce NOx?
My knowledge of regen needs serious updating but for those that are even newer to the subject I bookmarked this video a few years back when I was trying to learn about it. The video is old, long and slow but has some good early basic info on regen. The discussion on how EGR is used to reduce NOx starts at about 14:50.
Mark
Cross-Country
Joined: Mar 2009
Posts: 51
Likes: 0
From what I read the urea and H2O freeze/thaw at the same temps so no changing of the dilution percentage occurs. Sound risky though when you know a fluid is going to freeze, then need to thaw out in a closed mechanical system.
Senior User
Joined: Jan 2005
Posts: 460
Likes: 0
I was reading in the manual that you can turn auto Regen off. Say like you are in a position where you don't want it going into Regen, but once you turn the truck off the next time you start it it goes back to auto Regen.
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Hotshot
Joined: Apr 2013
Posts: 10,118
Likes: 650
From: NH
1. Is the pressure differential pre and post particulate filter the only stimulus for regen or are there other factors (like timers or amount of fuel consumption) that can initiate the regen cycle in the 6.7 Ford?
2. Is any form of exhaust gas recirculation (EGR) used in the Ford 6.7 to reduce NOx?
Hotshot
Joined: Apr 2013
Posts: 10,118
Likes: 650
From: NH
Troverman, is it your understanding that once the truck is started in temperatures below 12 degrees F, the DEF tank "heating" (I am assuming it is electric) would kick in to thaw the DEF in the tank?
From what I read the urea and H2O freeze/thaw at the same temps so no changing of the dilution percentage occurs. Sound risky though when you know a fluid is going to freeze, then need to thaw out in a closed mechanical system.
From what I read the urea and H2O freeze/thaw at the same temps so no changing of the dilution percentage occurs. Sound risky though when you know a fluid is going to freeze, then need to thaw out in a closed mechanical system.
The tank / pump / line heaters are all electric and are controlled by the Glow Plug module. I'm not certain of the exact temp when the tank starts heating, but I'd say its safe to assume its above 12F. Wind chill from driving down the road could freeze the solution at temps above 12F in my opinion.
As I mentioned, each time you shut your truck off, the DEF pump in the tank operates in reverse for a brief period of time. This allows it to suck all the DEF which is in the line and at the dosing injector back into the storage tank. That helps prevent a solid freeze (and possible damage) of the line or injector. If your truck has sat all night and its zero degrees, you'll have a nice frozen block of DEF in the morning. The truck will start and you will be not meeting EPA emissions requirements until the heating elements can melt the DEF and injection can begin.
There are plenty of checks and sensors which notice if any component fails, including the heaters. These will render a MIL and possibly an engine reduced power / speed mode.
Hotshot
Joined: Apr 2013
Posts: 10,118
Likes: 650
From: NH
Now, it isn't difficult to 'stop' an active regen once it starts...for example, any time the vehicle is in Park, is traveling less than 4mph, or the engine is shut down all stops a regen...but it will try to resume on the next trip.
Cross-Country
Joined: Mar 2009
Posts: 51
Likes: 0
Think of DEF as a solution - the ammonia and water and blended and will freeze and unfreeze together. The ammonia obviously lowers the freezing point - otherwise, it'd be 32F.
The tank / pump / line heaters are all electric and are controlled by the Glow Plug module. I'm not certain of the exact temp when the tank starts heating, but I'd say its safe to assume its above 12F. Wind chill from driving down the road could freeze the solution at temps above 12F in my opinion.
As I mentioned, each time you shut your truck off, the DEF pump in the tank operates in reverse for a brief period of time. This allows it to suck all the DEF which is in the line and at the dosing injector back into the storage tank. That helps prevent a solid freeze (and possible damage) of the line or injector. If your truck has sat all night and its zero degrees, you'll have a nice frozen block of DEF in the morning. The truck will start and you will be not meeting EPA emissions requirements until the heating elements can melt the DEF and injection can begin.
There are plenty of checks and sensors which notice if any component fails, including the heaters. These will render a MIL and possibly an engine reduced power / speed mode.
The tank / pump / line heaters are all electric and are controlled by the Glow Plug module. I'm not certain of the exact temp when the tank starts heating, but I'd say its safe to assume its above 12F. Wind chill from driving down the road could freeze the solution at temps above 12F in my opinion.
As I mentioned, each time you shut your truck off, the DEF pump in the tank operates in reverse for a brief period of time. This allows it to suck all the DEF which is in the line and at the dosing injector back into the storage tank. That helps prevent a solid freeze (and possible damage) of the line or injector. If your truck has sat all night and its zero degrees, you'll have a nice frozen block of DEF in the morning. The truck will start and you will be not meeting EPA emissions requirements until the heating elements can melt the DEF and injection can begin.
There are plenty of checks and sensors which notice if any component fails, including the heaters. These will render a MIL and possibly an engine reduced power / speed mode.
I am going to a diesel this round due to the lack of the V10 being offered. Hopefully it won't become problematic.
Senior User
Joined: Jun 2010
Posts: 344
Likes: 5
From: Pennsylvania
As soon as there is some custom tuning available, they should be able to. But unlike my 6.0, I won't be messing with this one. Got a 96 month/100,000 mile bumper to bumper warranty on it. Not going to jeopardize that.