# Regeneration Question



## Roadburner440 (Dec 29, 2013)

I remember about a week or so ago someone posting up a diagram of the exhaust and SCR system. Was looking for that to try and get my answer but using the search function I haven't been able to find it.. Been reading up about the regeneration process, and apparently there are two ways for the car to inject fuel during a regen. So what I was wondering was if our cars inject extra fuel into the cylinders on the exhaust stroke, or if there is a seperate diesel injector ahead of the DPF doing the injection during regen? Guess on the Duramax GM goes with the injecting fuel into the cylinders on the exhaust stroke method, but searching all over the web has led to no mention on how it is done on the Cruze.

I will say with the Volt that is one thing the GM engineers got right. We had a "maintenance mode" that would occur on the Volt if the gas engine had not been run in 42 days. However 24 hours prior the car would give you a message on the Mylink saying that it needed to do this in the next 24 hours, and would give you the option to accept/decline so that way you could run it when it was most efficient/convenient to do so. Not only that you could plan it. I don't know why they did not do a similar thing with the DPF regeneration on the Cruze TD. At some point before a normal regen occurs it could just pop up with a message X amount of miles ahead of time, and warn you so that way you could plan a longer drive if need be. Not having a light or any other indication seems to make no sense, and just leaves me with a lot of questions about it.


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## Tomko (Jun 1, 2013)

There is no extra injector. It is done in a similar way to Duramax. 

You propose an interesting idea. The problem is that a regen is triggered by a sensor - not by a time counter as with volt - therefore it would not be able to give a valid warning as to how many miles or hours are needed before a regen could occur. Only the status of the sensor to indicate that a regen is impending. 

At the end of the day, GM appears to take the view that regens should be seamless to the operator. And that the less information given, the more routine that function is to the operator.


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## MilTownSHO (Oct 9, 2013)

Interesting idea, let you know when a regen is going to be needed and pick when it starts (for example when you know you will be cruising on the freeway for awhile.)


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## Roadburner440 (Dec 29, 2013)

That is unfortunate. Reading about how the diesel strips oil from the cylinder walls when injected in to the cylinders that way during a regen is sort of worrisome. I will trust that the engineers knew what they were doing though.

I do realize that the regeneration isn't calender based. However in one of the Duramax tuner videos the guy had EFI Live hooked up and it had a gram count for soot in the DPF. He was saying it regens when there is around 21 grams or so of soot in the DPF. So my line of thinking was to just have a trigger at say 19 or 20 grams for that message to pop up saying you need a regen soon. Accept/decline like in the Volt, and it hits that 21 gram level it will just regen automatically like normal without giving you the option of declining. Which is what the Volt does if you decline for that 24 hour period for the engine maintenance mode. Seems to me that would have been the smarter thing for them to do but time will tell. I just hope all of these emissions bugs get ironed out, but in the mean time just going to do what I can to try and learn about the system.


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## Tomko (Jun 1, 2013)

I take your point - but it would potentially interfere with the EPA rating should someone initiate a regen when it was close to necessary but not absolutely necessary. 

Again, GM is trying to market this as a seamless transition from gasoline. So introducing a new thought process could send Susie homemaker into an anxiety filled moment that would not end well for her husband.


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## boraz (Aug 29, 2013)

http://www.cruzetalk.com/forum/201-...scussion/83745-p24c6-code-4.html#post13731057



5 O'Clock Charlie said:


> Yeah, it's a pretty complicated system ..... I bought a set of the manuals, mostly because I hate not knowing how something works and so I can't get bullshited at the dealer. But luckily 11 months and 34000 km without a snag !
> 
> Here's a snapshot of all the components in the exhaust system.
> 
> View attachment 109273


.


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## grs1961 (Oct 23, 2012)

The DPF system has been used for passenger vehicles in the rest of world for quite a while now, my diesel Cruze was built five years ago, and is ticking along quite nicely at +80 000km, thank you.

It seems to be the fear of the unknown, and the "people here won't buy diesel cars"[1] hangover that gets people worried, although GM USA's occasionally slipshod build process doesn't help.

1 - Of *course* they won't buy them if you *don't* supply them. I explained that to an exec from an un-named automotive company some decades ago, and had to be restrained from getting a LART[2] to ensure the message got through.

2 - Luser Attitude Re-adjustment Tool, at a previous employer I was presented with on that was a limb that had fallen from a Red Gum Tree, it need no modification to be thoroughly intimidating!


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## Roadburner440 (Dec 29, 2013)

Thank you Boraz. Is exactly what I was looking for, and explains why I couldn't find it. Thought it was its own titled thread and wasn't looking for that title. I don't have an issue with the DPF system, and did a little research on it before buying the car and seen it has been in use on other vehicles for awhile. Just want to make sure I do what I can to ensure the car lasts for as long as possible with as few issues as possible. Intend on driving it till the wheels fall off which is part of the reason I sprung for the CTD instead of a gas like others in my family.


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## nascarnate326 (Jun 9, 2014)

We have yet to see anything about rejen. How often does it happen? We have just under 8k on it. 

I intend to drive it like we do any other car.


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## revjpeterson (Oct 2, 2013)

nascarnate326 said:


> We have yet to see anything about rejen. How often does it happen? We have just under 8k on it.
> 
> I intend to drive it like we do any other car.


There is no instrument panel light or DIC message to indicate regens. The first few regens after new can be identified by an odor that is similar to burning plastic as some protective coatings burn off of the exhaust components, but otherwise, the only way to identify a regen is by noticing the subtle changes in the car's behavior, such as decreased fuel economy for approximately 15-20 miles, and a fan that might run after the engine is shut down. Incomplete regens will simply restart when the engine reaches the appropriate operating conditions during the next drive cycle. In the event a regen is interrupted too many times or the need for the regen becomes too urgent, you will see a message in the DIC that instructs you to keep driving above a certain speed until it completes. 

The regens on this car have been kept as subtle as possible (seemingly by design to avoid confusing people new to Diesels or scaring off potential buyers with the higher learning curve), so identifying them is mostly a matter of being familiar with your vehicle and its behavior. They occur approximately every 500-800 miles, so you have probably had nearly a dozen of them during your time of ownership without even noticing.


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## rleist (Oct 9, 2014)

Folks, any aftermarket solutions available to indicate when regen is happening? I know some of the tuners for the duramax will indicate it. And could have sworn my 2011 duramax had an extra injector. Thanks.


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## Scott M. (Apr 23, 2013)

I haven't found any yet. Edge CTD will monitor soot though. 22 grams of soot initiates a regen.


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## PanJet (Jun 18, 2013)

rleist said:


> Folks, any aftermarket solutions available to indicate when regen is happening? I know some of the tuners for the duramax will indicate it. And could have sworn my 2011 duramax had an extra injector. Thanks.


I believe you're correct. The earlier LMM Duramax ('07.5-'10) was the first Duramax with a DPF, and it did not have an extra injector, but I'm pretty sure an extra injector was added to the LML Duramax ('11-current).


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