i30 Owners Club
GOT PROBLEMS OR ISSUES? => DIESEL => Topic started by: bryand on July 11, 2013, 12:44:42
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Has anybody succeeded in using OBDII software to monitor the state of their Diesel Particulate Filter? Ideally, I want to know when it is about to start a regeneration cycle, but any measurements would be helpful. The objective is to modify my driving style to avoid DPF regeneration entirely or reduce it to a minimum.
Of the things I can already measure and log over the OBDII, which of these might indicate something about DPF state, and how?:
- RPM
- Instantaneous MPG
- Instantaneous CO2 production
- Air:Fuel ratio
- Exhaust Gas recirculation (%)
- Turbo boost
- Accelerator Pedal depression (%)
Any thoughts or pointers welcome. (What I really want is exhaust gas temperature, but that's not reported by my dongle).
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I guess that you need to monitor the pressure drop across the DPF which is an indication of the amount of particulates building up in the filter.
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I wouldn't think you would be able to monitor the DPF with an OBD II really as its not an engine part as such, but like Alan said if you could it would probably be something to do with back pressure building up in the exhaust which would trigger it.
I dont think there would be a sensor for the exhaust gas temperature as they usually stick a rod or some sort in the exhaust pipe to get readings.
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Instantaneous MPG would be an indicator, however, because it is instantaneous, you would need to observe a continuous increase for a period of time in order to conclude DPF is occurring.
You can't change your driving style to avoid DPF regenerations as particulates are a part of diesel combustion, no matter how you drive. Switching the engine off does have the desired effect, but is not conducive to efficient travel. :undecided:
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The objective is to modify my driving style to avoid DPF regeneration entirely or reduce it to a minimum.
I am surprised Alan didn't say this (but I'm sure he thought it) ...
DPF regeneration is a necssary evil (if you have a DPF) If it doesn't happen fairly regularly then the DPF will need manual cleaning or replacement (at a high cost)
So if you are unlucky enough to have one fitted (still not the case in Aussie delivered i30's as far as I am aware) then you just have to cop it sweet.. :disapp:
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Will be good to know when is happen to keep driving to finish cleaning.
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I just had a quick search around and apparently you can remove the DPF and it will still be legal and pass the MOT according to this article but it was published a 2 yrs ago, so if it does go belly up u can get it removed instead of forced regeneration which will cost at least twice as much.
http://www.carmagazine.co.uk/Community/Car-Magazines-Blogs/Chris-Chilton-Blog/Are-diesel-particulate-filters-more-trouble-than-theyre-worth/ (http://www.carmagazine.co.uk/Community/Car-Magazines-Blogs/Chris-Chilton-Blog/Are-diesel-particulate-filters-more-trouble-than-theyre-worth/)
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You can't change your driving style to avoid DPF regenerations as particulates are a part of diesel combustion, no matter how you drive.
From what I have read on here, driving long enough at motorway speeds (70 MPH, 2300 RPM+) encourages 'passive regeneration' because the DPF gets hot enough to burn off the soot in normal (albeit fast ) driving. This would avoid the active regeneration where extra fuel is used to increase exhaust temperatures and burn the soot off.
What I want to do is optimise my driving style to maximise the amount of passive regeneration. I think variations in the passive/active balance account for some of the variations in MPG reported by UK i30 diesel owners.
In a general sense, I don't like DPFs because the convert solid carbon (soot) into something we are trying to get rid of - carbon dioxide. There's only so much carbon in a litre of diesel, so it comes out as unburnt hydrocarbons; carbon monoxide; carbon dioxide or soot. So I'm glad to hear I can legally remove the DPF if necessary, and get the car remapped at the same time.
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Your theory works if you have ultimate control over when and where you choose to drive. Most people have to mix motorway driving with suburbia due to work commitments and there begins the build up of particulates. Even our retired member, Alan Ho, can not avoid DPF regenerations in his vehicle.
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Luckily, I more or less do have that control: I live within walking distance of work, on the edge of a small town.
My objective is to minimise fuel-guzzling active regenerations by trying to arrange for conditions where passive regeneration can happen as much as possible. If that doesn't work, I'll seriously consider a DPFectomy.
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I'll seriously consider a DPFectomy.
I like your style
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Yesterday I drove back from Cumbria via the M6, M6 Toll and M42 - covering a distance of 183 miles of which 162 miles were on the motorways. It was 20.20 when we set off and 22.55 when we arrived home. Average speed for the whole journey was thus 71 mph. Traffic on the motorways was light and I was able to constantly cruise at 80 to 85 mph (128 to 136 kph). After 133 miles on the motorway I noticed that the fuel consumption had increased - the DPF was regenerating 263 miles after the previous regeneration which occurred on the motorway on the way up. The car was heavily laden with 2 up, a lot of luggage and all the shopping management had crammed in - plus some heavy granite rocks she was bringing home for our garden rockery. I had maintained a consistent high speed and the engine had been worked hard - especially at the north end of the motorway where there are a lot of inclines. Despite this hard work the DPF still felt the need for a good cough with the attendant significant effect on economy. This is not the first time I have noticed this and I have come to the conclusion that the i30 DPF regenerates every 250 to 280 miles regardless of how you drive.
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So it seems to fly in the face of the fact they put out about diesels being good on mpg and on the environment
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Yesterday I drove back from Cumbria via the M6, M6 Toll and M42 - covering a distance of 183 miles of which 162 miles were on the motorways. It was 20.20 when we set off and 22.55 when we arrived home. Average speed for the whole journey was thus 71 mph. Traffic on the motorways was light and I was able to constantly cruise at 80 to 85 mph (128 to 136 kph). After 133 miles on the motorway I noticed that the fuel consumption had increased - the DPF was regenerating 263 miles after the previous regeneration which occurred on the motorway on the way up. The car was heavily laden with 2 up, a lot of luggage and all the shopping management had crammed in - plus some heavy granite rocks she was bringing home for our garden rockery. I had maintained a consistent high speed and the engine had been worked hard - especially at the north end of the motorway where there are a lot of inclines. Despite this hard work the DPF still felt the need for a good cough with the attendant significant effect on economy. This is not the first time I have noticed this and I have come to the conclusion that the i30 DPF regenerates every 250 to 280 miles regardless of how you drive.
I wouldn't be surprised if its been programmed in to the ECU to do that as a fail safe, just in case people mainly do short runs.
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Well, I've made some progress, by discovering that the OBDII PID "Catalyst temperature Bank 1 Sensor 2" is available on the i30.
Now can anybody confirm that the object inside the silver sleeve in the photo is indeed the cat? If so, it's very close to the DPF, so monitoring the cat temperature could be a surrogate for the DPF temperature. That will only confirm that a DPF regeneration cycle has already begun, of course, not that it's about to happen.
(http://i58.photobucket.com/albums/g280/cobrd/i30/isthisthecat.jpg)
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No it's not the cat.
Here are some pics of catalytic converters. They are usually housed in a sealed casing.
http://photobucket.com/images/Catalytic+Converter/?page=1 (http://photobucket.com/images/Catalytic+Converter/?page=1)
More pics, notice in pic 4 the converter and forward of that two similar pipes like your pic. Pic 3 is the converter.
http://www.audizine.com/forum/showthread.php/445871-SSAC-Exhaust-Flex-pipes-Cats-V-bands-INSTALLED-Pics-inside (http://www.audizine.com/forum/showthread.php/445871-SSAC-Exhaust-Flex-pipes-Cats-V-bands-INSTALLED-Pics-inside)
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OK so having had some success with tracking down regeneration using OBDII, I thought I would try to summarise some of what we've all learnt. My thanks to the other contributors whose stuff I have incorporated (and hopefully acknowledged)
DPFs: what do we know?
The Kia/Hyundai 1.6L diesel uses a Catalysed Particulate Filter (CPF) i.e. a catalytic converter bolted to the output of the turbo at the back of the engine, with a Particulate Filter in the bottom 2/3rds of the CPF canister, as shown below.
(http://i58.photobucket.com/albums/g280/cobrd/i30/context.jpg)
[source: http://www.engine-expo.com/forum_2009/pdfs/day2/5_sunghwan_cho.pdf (http://www.engine-expo.com/forum_2009/pdfs/day2/5_sunghwan_cho.pdf) slide 25]
So if you were going to remove the CPF, you would have to remove the whole shebang and replace it with just a catalytic converter. This is precisely what some performance aftermarket exhausts do. You would also have to remap the engine so it didn’t try to regen a non-existent CPF.
Close-coupled DPFs don’t use magic liquid, just heat to remove soot.
Passive regeneration takes place above 2250 RPM, minimising soot build-up. My observations of the Catalyst temperature reading available over the OBD suggests that you need to be travelling at 60 MPH in 6th to reach 400°C, and over 70 MPH to reach 500°C.
An active regen cycle takes about 20 minutes and involves extra injections per power stroke:
• A pre-injection to quieten it down;
• Then the main quantity and
• two post-burn doses which get flushed out into the DPF.
When a DPF regen cycle is going, the turbo vanes are wide open and the EGR valve is shut, so no EGR is happening.
During a regen cycle we can expect OBDII monitoring to show:
• Catalyst Temperature – significantly higher than normal
• Exhaust Gas Recirculation (EGR) – should be at minimum value (4.71%) = OFF
The Catalyst Temperature is reported on OBDII as “Catalyst Temperature Bank 1 Sensor 2”, and has been observed to range from 110°C to 540°C in normal, spirited driving.
This is monitored whilst driving using Torque Pro running on an Android smartphone whichg is being fed with OBDII data from a VGate Bluetooth dongle (£25 on eBay). When the Cat B1 S2 value gets to more than 575°C, you’re in regen territory.
(http://i58.photobucket.com/albums/g280/cobrd/i30/49932cab-d466-4cd9-9143-f0d70dd79c28.jpg)
This image below is from an eBay advert for an i30 CPF and shows the whole thing (it’s about the size of a Rugby ball).
It seems plausible that the pipework feeds two sides of a differential pressure sensor which can trigger a regen cycle. However the evidence from members suggests that regens triggered by distance are more common.
My OBDII temperatures come from one of the two sensors shown - probably the one between the catalytic converter at the top and the DPF at the bottom of the canister.
(http://i58.photobucket.com/albums/g280/cobrd/i30/CPF_labelled.jpg)
How frequently does it need a regen?
My guess is that the same CPF is used on all three flavours of the 1.6 Kia/Hyundai diesel (90, 115 and 128 HP versions). It would be logical if the higher-powered versions filled their DPF canisters more quickly than the less powerful engines, and hence regen more often.
So from the Hyundai and Kia forums we get:
AlanHo 128 HP Hyundai Regen every 260 miles
SportWagon 115 HP Kia Regen every 300 miles
neoto 90 HP Hyundai Regen every 435 miles
So is the Hyundai CPF simply too small to hold a sensible amount of soot before it needs to regen?
How hot does it need to be?
“Catalyzed Diesel Particulate Filters (CDPF) are designed not only to achieve collection efficiencies of 90% or greater in terms of mass (over 95% when expressed as number of ultra fine particles), but also to burn off the collected particulate matter into carbon dioxide and water…The incorporation of a catalytic coating in CDPFs lowers the temperature at which particulate matter burns. To achieve this auto-ignite and the sustained combustion of collected particulate matter CDPFs must attain a minimum temperature of approximately 250°C”.
[source: http://www.tdciforum.co.uk (http://www.tdciforum.co.uk), quoted in http://www.honestjohn.co.uk/faq/diesel-particulate-filters/, (http://www.honestjohn.co.uk/faq/diesel-particulate-filters/,) 19/7/13]
“Only a portion of the particulates are converted to carbon dioxide during passive regeneration and due to chemical reaction this process is only effective within the temperature range of 250°C to 500°C. Above this temperature range the conversion efficiency of the particulates into carbon dioxide subsides as the temperature of the filter increases.
Active regeneration takes approximately 20 minutes to complete. The first phase is to raise the temperature of the filter to particulate combustion temperature of 500°C.
In the second phase the temperature is raised to 600°C, the optimum particulate combustion temperature. This temperature is maintained for 15 to 20 minutes to ensure complete incineration of the particulates captured in the filter. The incinerated particulates produce carbon dioxide and water.”
“Temperature before the turbocharger inlet must remain below 830°C for turbocharger protection.
Close-coupled catalyst in-brick temperatures must not exceed 800°C and exit temperature must remain below 750°C”
[source: “DPF Use and Regeneration – For Technophiles” by AlanHo https://www.i30ownersclub.com/forum/index.php?topic=13595.msg149163#msg149163 (https://www.i30ownersclub.com/forum/index.php?topic=13595.msg149163#msg149163) ]
Rules of thumb
“Needs to run at > 2,250 RPM for > 45 minutes every month.”
“During the regeneration, the fuel consumption is higher for about 2-3l/100km”
[source: neoto reply #1 in https://www.i30ownersclub.com/forum/index.php?topic=13595.msg149163#msg149163 (https://www.i30ownersclub.com/forum/index.php?topic=13595.msg149163#msg149163) ]
If the car needs an ACEA C3 oil, it’s got a CPF. [source: i30 owner’s manual]
Using diagnostics
You can use OBDII diagnostics to show when a regen cycle is happening. I didn’t manage to log the start of a cycle, but the end is flagged by EGR turning back on from the fully-off state during the regen cycle, and the Catalyst temperature drops by about 200 °C:
(http://i58.photobucket.com/albums/g280/cobrd/i30/3e43b545-47af-4f13-b126-a449248e6c03.jpg)
I'm happy to be corrected on any of this, but it makes sense to me. I'll try to catch the start of the next regen cycle on my car and see what is triggering it. The attached document describes the PIDs which I can log with my OBDII setup (on a 2011 FD i30 Comfort).
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Thanks very much Bryan :goodjob2: :goodjob:
Doesn't directly affect me but many others will find it very informative :cool:
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:wss:
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:iws:
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:Agoodpost: :goodjob2: :goodjob:
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I also monitored my dpf using torque and an elm 2 obd 2 adapter, but I left the elm connected and torque running on the phone, in background, with log enabled. In this way I caught all regenerations in the last 3000km.
Before buying the elm I monitored regenerations using instantaneous fuel flow indication which, during regenerations, is not zero when decelerating.
From all monitoring I could not find the law that describes when regeneration starts. For my car it starts at random distances between 200 and 300Km (not miles). When I had incomplete regenerations, it restarted after 5 to 60Km. I had regenerations starting after driving on highway for about 1 hour or when climbing a mountain for more than 20', or even during dynamic braking. So, at least for my car, passive regeneration is not taken into consideration by ecu.
However I noticed that:
1. Regeneration takes 17' if driving on highway, but in town it can take even more than 40' because ecu tries to get 17' with temperature above 540 degrees,
2. Regeneration is suspended (temperature decreases below 300 degrees) if engine is at idle and car stopped for 4',
3. Regeneration is suspended during dynamic braking if engine rpm does not decrease but increase,
4. Regeneration is immediately resumed if engine was not shut down, speed increases and acceleration is pressed,
5. Regeneration is performed even with engine at idle,
6. Injection for regeneration (post injection) can produce power, for instance in idle, pilot and main injection quantities are reduced from 5-7mm3 (7 with AC) to <2.5mm3 and post injection is 7-8mm3,
7. Post injection is reduced during acceleration and maximum post injection was 17mm3/stroke,
8. Driving at lower rpm (higher gear) produces higher temperatures at same speed,
9. Driving at lower rpm increases fuel economy all the time, not only during regenerations.
The car has sensor to measure pressure drop on dpf. Unfortunately torque does not read it. There is a plug in for torque for Hyundai engines with a lite and a pro version. The lite version does not read dpf pressure drop. Does anyone know what sensors reads the pro version?
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AFAIK, the law of regeneration is purely determined by two sensors, one on each side of the DPF. The difference in these sensors is the initial trigger for regeneration, subject to all the other requirements being satisfied, to commence regeneration.
That's good info you've provided, nicu, post number 1, too. :goodjob2:
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I just had a quick search around and apparently you can remove the DPF and it will still be legal and pass the MOT according to this article but it was published a 2 yrs ago, so if it does go belly up u can get it removed instead of forced regeneration which will cost at least twice as much.
:link: Are diesel particulate filters more trouble than help? | Car Blogs | Car Magazine Online (http://www.carmagazine.co.uk/Community/Car-Magazines-Blogs/Chris-Chilton-Blog/Are-diesel-particulate-filters-more-trouble-than-theyre-worth/)
Not so. If the car required a DPF to obtain Type Approval then it is illegal to remove or modify it which could lead to an up to £1000 penalty.
DfT had stated that any cars that have had DPF removal will fail the MOT from February 2014.
:link: New rules for MOT to test for diesel particulate filter - Press releases - GOV.UK (https://www.gov.uk/government/news/new-rules-for-mot-to-test-for-diesel-particulate-filter)
http://tinyurl.com/ogkrqel (http://tinyurl.com/ogkrqel)
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AFAIK, the law of regeneration is purely determined by two sensors, one on each side of the DPF. The difference in these sensors is the initial trigger for regeneration, subject to all the other requirements being satisfied, to commence regeneration.
I think it's determined to trigger when the car thinks you have only few kilometers to go before your destination! :P
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:lol: :head_butt:
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AFAIK, the law of regeneration is purely determined by two sensors, one on each side of the DPF. The difference in these sensors is the initial trigger for regeneration, subject to all the other requirements being satisfied, to commence regeneration.
That's good info you've provided, nicu, post number 1, too. :goodjob2:
On Hyundai's there is a hose before and after the DPF which run to a pressure differential sensor. One hose to each side of the sensor which reads pressure difference.