# Anatomy of a DPF regen



## bostonboy (Apr 8, 2015)

I was thinking of getting that unit what do you think of it? pros & cons please thanks This is what I have been looking at the cts 2

Edge Insight cts 2 84130 Ford GMC Chevy Dodge Authorized Distributor | eBay


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## Aussie (Sep 16, 2012)

Why doesn't the Chevy come with a "drive me hard" light like the Holden CTD does? When it comes on you just drive keeping the engine over 2,000rpm until the light goes out, job done. By the way, mine has only come on once in 36K.


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## obermd (Mar 3, 2012)

Aussie said:


> Why doesn't the Chevy come with a "drive me hard" light like the Holden CTD does? When it comes on you just drive keeping the engine over 2,000rpm until the light goes out, job done. By the way, mine has only come on once in 36K.


Because some idiot would interpret "drive me hard" as instructions to ignore traffic and traffic laws, get into an accident, and then file a lawsuit against GM.


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## diesel (Jun 8, 2013)

bostonboy said:


> I was thinking of getting that unit what do you think of it? pros & cons please thanks This is what I have been looking at the cts 2
> 
> Edge Insight cts 2 84130 Ford GMC Chevy Dodge Authorized Distributor | eBay


I got the older one it's just called the Edge Insight CTS which is about $100 cheaper than the one you posted. It works well and I am glad I bought it. Can't really think of any cons.


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## diesel (Jun 8, 2013)

Aussie said:


> Why doesn't the Chevy come with a "drive me hard" light like the Holden CTD does? When it comes on you just drive keeping the engine over 2,000rpm until the light goes out, job done. By the way, mine has only come on once in 36K.


I really wish it did. It would save people unnecessary trips to the dealer. I wonder if the VW TDI's have it.


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## oilburner (Jun 13, 2013)

diesel ...... how many miles between regens??


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## diesel (Jun 8, 2013)

oilburner said:


> diesel ...... how many miles between regens??


I haven't paid attention to that piece of data yet. It was really strange to me, the past couple days the gauge stayed at 10 grams soot for like 400 miles. Before that 3-9 went extremely fast, even a couple miles per gram. Then from 11-15 it was like 50 miles per gram. I don't think the soot grams are very accurate. I'd estimate between 600-800 miles between regens.


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## verstohlen (Mar 21, 2015)

Just completed one. Had a feeling it was gonna occur, hit 21 Soot g yesterday and was gonna see if it hit 22 before it started and it didn't. On my way home after work I stopped at a gas station to get a drink. I looked at my monitor and had already dropped 2 grams just cruising 55 light driving. So I left it running and I got back to the car and at idle it burnt two more. But my DPF Stat PID read off, so I switched it out for some EGT's and watched that In comparison with reduction in grams. I dropped into 5th going 75 for a bit but temps remained pretty close as cruising 6th same speed surprisingly. My regen took a bit longer than 8min, had to take some back roads past my house before she was done. 

Edit: looking back at Edge manual, and as I figured when DPF stat said off, and the alert indicator had R flashing on and off ocassionally, that was nice.


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## diesel (Jun 8, 2013)

I just had a regen happen in stop and go traffic. I made a long, boring video but can't seem to upload it at the moment. Basically the DPF Stat would turn off while I was driving slowly, however the grams of soot would continue to drop. It looks like the regens can happen even when you are driving slowly.

The stranger part of this is that It only took 200 miles or so to get up to 18 grams. The it stayed on 18 grams for 500 miles. It stayed on 19 grams for 250 miles. For the first time, it went up to 20 before it started a regen. I got just under 1000 miles in between regens this past time. I got a little nervous when it got to 20 because it never went that far before, since I have been observing.


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## IndyDiesel (May 24, 2015)

A few weeks ago I was seriously considering purchasing a Cruze Diesel, 14 or 15, when I was doing my research I stopped and test drove a 15, I asked the Service Manager about the Regen, the sales guy didn't really know much ( go figure), but he did get me to service manager, he printed off the tech specs from Chevrolet for me, I think I still have them. As I recall for it to complete you needed to be going 30 mph for a short period of time, maybe 15 min or so. I will double check but that is what I recall. Also looked at Passat and Jetta and they have customers that drive short distances and owner doesn't understand how the regen works and sometimes it goes into limp mode as well. I am waiting for the 17 diesel, hoping it has the regen on the on board screen so it is easier to monitor. Probably wishful thinking.


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## Tomko (Jun 1, 2013)

I'm not aware of any diesel passenger vehicle that comes from the factory with a regen indicator.


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## Just Rick (Jun 23, 2015)

I know the Aust version don't have them 

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## Aussie (Sep 16, 2012)

Tomko said:


> I'm not aware of any diesel passenger vehicle that comes from the factory with a regen indicator.


The Holden Cruze diesel has a light that comes on when you need to finish a regen. We call it the drive me hard light. The manual says that if this light comes on to keep driving and keep the engine above 2,000rpm till the light goes out. In 37,000km this has only happened to me once and took about 10 minutes to go out.


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## Cruzator (Dec 31, 2014)

Here is a little info I got from ShopKey Pro website. May be TMI, but gives some mileage stats for regen, etc.

Particulate Matter Sensor (PMS) 
The PM sensor determines the amount of the particulates (soot) in the diesel exhaust gas exiting the tailpipe by monitoring the collection efficiency of the DPF and to aid in OBD-II emission diagnostics.
The PM sensor is similar to the heated oxygen sensor with a ceramic element but also includes an individually calibrated control unit. The PM sensor sensing element includes two comb-shaped inter-digital electrodes, a heater and a positive temperature coefficient (PTC) resistor for temperature measurement.
The operation of the PM sensor is based on the electrical conductivity characteristic of the soot. As the exhaust gas flows over the sensing element, soot is absorbed in the combs between the electrodes, eventually creating a conductive path. When the path is formed, it generates a current based on the voltage being applied to the element. The measurement process continues until a preset current value is reached. To avoid misleading readings, the sensor operates on a "regenerative" principle, where the soot is cleaned off by heating up the element to burn off the carbon, before the measurement phase begins. The amount of regenerations is based on vehicle strategy; when the amount of regeneration is reached, the cumulative current readings are used to determine the amount of soot concentration in the exhaust gas and thus the collection efficiency of the DPF.
The PM sensor is operated in 3 successive modes:


Standby mode after power-up to ensure protective heating. On power-up, the control unit starts the heating process to avoid condensation of liquids on the sensing element. Presence of liquid can cause thermal shock during the heating process, resulting in damage to the ceramic element. Regeneration is not initiated until the dew point temperature has been exceeded.
Regeneration mode is conducted before each measurement to ensure a soot free sensing element. Before starting measurements, absorbed soot is burned off the sensing element by heating it up; this ensures each measurement start off at the same condition. Regeneration is conducted for a pre-determined period of time based on soot level.
Measurement mode is when soot is actively collected on the sensing element. The sensor heater is deactivated during measurement, so the temperature on the element is equivalent to that of the exhaust gas. Voltage is applied until a preset 12 micro-amp current threshold is achieved due to increasing current as the soot builds up on the element. The time from the end of the regeneration to reach the threshold is used to calculate the concentration of soot in the exhaust gas.
 Differential Pressure Sensor (DPS) 
Pressure connections at the DPF inlet and outlet allow the DPS to measure the pressure drop across the diesel particulate filter. This pressure drop increases as trapped soot collects in the cells of the DPF during vehicle operation. The rate at which soot collects varies with the power demands placed on the engine. If left unchecked, the increasing backpressure will eventually result in a drivability problem. There are two sensing elements in the DPS; one for the upstream side of the DPF and the other for the downstream side. Pressure from each side of the DPF is applied to the bottom side of a silicon diaphragm in each sensing element; atmospheric pressure is applied to the top side of each diaphragm. Relative pressure differences in each sensing element is converted to a voltage (V1 & V2). The difference in these voltages is sent to the ECM. As the DPF becomes clogged, the pressure on the upstream side increases because of back pressure due to the restriction of the exhaust gas flow through the DPF.
Normal DPF Regeneration 
Over time, the soot trapped on the cell walls acts to restrict exhaust flow through the DPF reducing its effectiveness as well as reducing engine efficiency. This restriction in exhaust flow produces a pressure drop across the DPF that increases as the once porous cell walls become saturated with trapped soot. A DPS monitors the pressure drop across the DPF and provides the ECM with a voltage signal proportional to soot buildup. Once soot buildup reaches a specified limit, (usually around 22 - 25 grams) as signaled by the increased pressure drop across the DPF, the ECM commands a regeneration event to burn-off the collected soot during normal vehicle operation. Regeneration events occurring during vehicle operation are known as normal regenerations as they occur automatically and without driver knowledge. In general, the vehicle will need to be operating continuously at speeds above 48 km/h (30 mph) for approximately 20-30 minutes for a full and effective regeneration to complete.
The frequency of normal DPF regeneration is a function of the engine run time, miles driven and fuel consumed since the last regeneration event. Under normal operating conditions, the normal DPF regeneration is initiated after approximately 85 gallons of fuel used or a maximum distance traveled of 2009 km (1250 miles.) To initiate a normal DPF regeneration event, the ECM commands additional fuel via post-injection in order to create the additional exhaust heat in the DOC necessary to promote regeneration and burn-off the collected soot.
During regeneration exhaust temperatures may exceed 550°C (1, 022°F) due to the rapid catalytic combustion of soot within the DPF. Conversely, under low engine speed or light loads, exhaust temperatures may be too low to promote proper regeneration. To protect the DPF catalyst from thermal damage due to excessive soot combustion or from sulfate poisoning at low temperatures, the ECM monitors EGT sensors upstream and downstream of the DPF during regeneration. If the vehicle is slowed to idle speed during a normal DPF regeneration, the engine may maintain an elevated idle of 800 RPM until the DPF is cooled to a calibrated temperature.
Should the EGT sensors indicate that regeneration temperatures have exceeded a calibrated threshold, regeneration will be temporally suspended until the sensors return to a normal temperature. If regeneration temperatures fall below a calibrated threshold, regeneration is terminated and a corresponding DTC is set in the ECM.
Under most conditions, the soot collected within the DPF burns off during normal regeneration cycles. Periodic regeneration prevents the buildup of soot from reaching a level where its burn-off could produce damaging high temperatures within the DPF. Vehicles operated at prolonged low speed or low loads where normal regeneration does not occur will eventually reach a high soot load condition. When the increased pressure drop across the DPF is detected by the DPS, the ECM illuminates the DPF lamp in the instrument cluster and sends a Clean Exhaust Filter message to the driver information center (DIC). The owner manual diesel supplement describes how the vehicle should be driven in order to enable normal regeneration.


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## Cruzator (Dec 31, 2014)

I had a regen happen yesterday. It was a 22 grams before it started (may of jumped to 23, but I didn't catch it). It ran for 12 miles on the highway (had a couple of minutes of stop time at one stop light). Dropped down to 2 when it completed. I, too, am curious how long it will go between regens. Do thiese things "make oil" like the for 6.4? I noticed my oil is a little overfull the last time I checked it, but I think it was overfull some when I got it back from the dealer from it's "free" oil change. Maybe I should drain some out. What is the opinion? How much is too much over full?


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## Robby (Mar 1, 2013)

I will guess, regarding oil level, that the dealer put five full quarts in rather than the 4.75qt specification.

This will show as about a 1/8" overfill on the stick…..although there will be some disagreement, 1/8" likely will cause no harm.
I would caution the dealer on the next service though…..Chevrolet sent a bulletin out, back when the Diesel was introduced, reminding dealers to avoid overfilling because of the heightened potential of a 'runaway'.

As the engine wears, specifically rings, way down the mileage road, the potential of a runaway with any amount of overfill increases……unlikely for your young, still tight, engine.

You mentioned an engine 'Making' oil.
This is a situation more specific to gasoline engines used for short trip, rarely fully warmed up, driving.
The short trips don't allow the engine to heat the oil enough to burn off the moisture (condensation) that occurs inside the engine as it warms up……most condensation is a result of normal ring blow by that occurs as internal parts haven't expanded fully yet.
The condensation is held in suspension by the oil…..as the cycle repeats, the oil level will rise…..but it is a mix of moisture and oil.
This is why oil changes are far more important on a short haul car…..also known as 'Severe' service……gotta get that evil mix out of the crankcase before the oil cannot hold any more moisture in suspension……water is a lousy lubricant.

Todays lesson,
Rob


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## diesel (Jun 8, 2013)

Some more info for those following this thread. I finally got to see what happens when you interrupt regens in progress, with some reasonable driving in between. basically it picks up where it left off. I stopped it at 13 grams and then again at 8 with city driving in between. it does not need highway driving to complete a regen. 

i also noticed that if i am at a stop, put it in neutral and rev to 2000 RPMS, it will re-initiate the regen. you don't even need to be moving.


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## diesel (Jun 8, 2013)

Cruzator said:


> I had a regen happen yesterday. It was a 22 grams before it started (may of jumped to 23, but I didn't catch it). It ran for 12 miles on the highway (had a couple of minutes of stop time at one stop light). Dropped down to 2 when it completed. I, too, am curious how long it will go between regens. Do thiese things "make oil" like the for 6.4? I noticed my oil is a little overfull the last time I checked it, but I think it was overfull some when I got it back from the dealer from it's "free" oil change. Maybe I should drain some out. What is the opinion? How much is too much over full?


I posted a while back about my oil being overfilled even when i added 4.75 quarts. i ended up draining out a cup of oil just to be safe.


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## revjpeterson (Oct 2, 2013)

Cruzator said:


> I had a regen happen yesterday. It was a 22 grams before it started (may of jumped to 23, but I didn't catch it). It ran for 12 miles on the highway (had a couple of minutes of stop time at one stop light). Dropped down to 2 when it completed. I, too, am curious how long it will go between regens. Do thiese things "make oil" like the for 6.4? I noticed my oil is a little overfull the last time I checked it, but I think it was overfull some when I got it back from the dealer from it's "free" oil change. Maybe I should drain some out. What is the opinion? How much is too much over full?





Robby said:


> You mentioned an engine 'Making' oil.
> This is a situation more specific to gasoline engines used for short trip, rarely fully warmed up, driving.
> The short trips don't allow the engine to heat the oil enough to burn off the moisture (condensation) that occurs inside the engine as it warms up……most condensation is a result of normal ring blow by that occurs as internal parts haven't expanded fully yet.
> The condensation is held in suspension by the oil…..as the cycle repeats, the oil level will rise…..but it is a mix of moisture and oil.
> This is why oil changes are far more important on a short haul car…..also known as 'Severe' service……gotta get that evil mix out of the crankcase before the oil cannot hold any more moisture in suspension……water is a lousy lubricant.


I think there is also another potential factor to a rising oil level in our Diesels, which would be fuel dilution due to cylinder wash during the re-gen process. Because our engines inject the fuel into the cylinder on the exhaust stroke rather than having an extra injector in the exhaust, there is the potential that unburned fuel can get into the crankcase oil. I remember reading about this when our Diesels were introduced, and people were expressing concern that the re-gen method could result in this. I also remember it being discussed in an oil analysis thread at some point. I wouldn't think this should be enough to cause a visible rise in oil level, though, unless there were an excessive number of re-gens during an oil change or something was out of order.


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## KpaxFAQ (Sep 1, 2013)

Yep if you get a real uoa other than blackstone, I guarentee you all have some fuel in your oil at the end of the interval. It's just the nature of the regen process


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## Robby (Mar 1, 2013)

diesel said:


> I posted a while back about my oil being overfilled even when i added 4.75 quarts. i ended up draining out a cup of oil just to be safe.


I helped a friend perform a oil change on his diesel Cruze some time ago…….don't like that drain plug one bit with the holes firing the oil sideways and what.

However, once it almost stopped dripping I took the plug completely out and probably drained an additional ten or more ounces out of the pan.
I speculate this too could end up making the engine slightly overfilled if using the 4.75 specification since the service manual does not call for full removal of the plug.

Just a thought,
Rob


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## BlueTopaz (Aug 25, 2012)

Robby said:


> I helped a friend perform a oil change on his diesel Cruze some time ago…….don't like that drain plug one bit with the holes firing the oil sideways and what.
> 
> However, once it almost stopped dripping I took the plug completely out and probably drained an additional ten or more ounces out of the pan.
> I speculate this too could end up making the engine slightly overfilled if using the 4.75 specification since the service manual does not call for full removal of the plug.
> ...


This is why I'm looking at getting the Fumoto Valve for mine.


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## Cruzator (Dec 31, 2014)

revjpeterson said:


> I think there is also another potential factor to a rising oil level in our Diesels, which would be fuel dilution due to cylinder wash during the re-gen process. Because our engines inject the fuel into the cylinder on the exhaust stroke rather than having an extra injector in the exhaust, there is the potential that unburned fuel can get into the crankcase oil. I remember reading about this when our Diesels were introduced, and people were expressing concern that the re-gen method could result in this. I also remember it being discussed in an oil analysis thread at some point. I wouldn't think this should be enough to cause a visible rise in oil level, though, unless there were an excessive number of re-gens during an oil change or something was out of order.


 Very well put. That was the "making oil" I was refering to.


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## vwgtiglx (Jun 13, 2013)

Cruzator said:


> Very well put. That was the "making oil" I was refering to.


This oil dilution was a problem in the Mazda 6 diesel in Australia/New Zealand. Mazda's solution to the problem was to change the gradations/length of the dipstick. I thought "how clever of them", why didn't I think of that? I guess Mazda now finally, just recently, gave up on the idea of bringing the car over here, due to emission certification issues.


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## money_man (Feb 25, 2014)

Mazda claimed to have a 16:1 compression gas engine coming out in North America for 2015-2016. Obviously that didn't work either. The bonus was better efficiency and no spark plugs, could, wires


Sent from the sexy electrician


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## Aussie (Sep 16, 2012)

Found this.

Mazda eyes 18:1 petrol compression - motoring.com.au


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