DPF removal and MOT failure - going beyond a visual check?

Sportacus

I found this statement on a government website:




https://mattersoftesting.blog.gov.uk/inspecting-diesel-particulate-filters/


"the inspection will initially be restricted to a visual examination for the presence of a DPF "


This implies that the check will become more than visual. Any thoughts if this would likely be plugging in to the ECU and checking the DPF status, or adding a new emissions check to measure the increased particulates?

gilbert_and_sullivan

I suspect any self respecting MOT tester would be able to tell from tapping the DPF canister whether it was empty or not, so if it echoes like an empty bucket expect it to fail.

Thats assuming the MOT tester gives a toss one way or another.

Would require some serious electronics to interrogate the system so i can't see that for some time.

Anyone who is really bothered could do as the hot hatch lads do with decats and slip a functioning DPF on for the test and remove once tested.

Meself, i can't be bothered with Diesels any more, far too complicated and troublesome.

Sportacus

yeah, they used to be great though. What are taxi firms using these days? They must have no end of trouble if using diesels, given the stop-start nature of taxi driving.

welfayre

I'd say it will more likely be an additional emissions check as no diagnostic machine is capable of reading every vehicle make/model and it would be unfeasable for MOT stations to buy a different machine for every vehicle.

I know the Euro 6 standards start to come into effect from September 2014 - September 2015 so maybe there will be a more definitive answer to your question in the information on that?

Iceweasel

I think it's inevitable that the test will be amended in future to check for a fully functioning DPF rather than just an empty box.

As for taxis - why would they have any problem?

Most taxis are never cold - just like delivery vans.

Stop/start is not the problem - it's school run type short journeys and then sitting for several hours before another short journey that means the engine never completes a re-cycle that blocks up the DPF.

Sportacus

but a London taxi will rarely get above 30mph, not hot enough to burn off the soot, and I can't believe regens are any good for the engine at all (adding fuel to the oil). I suspect the big companies might have agreements with DPF cleaning firms like ceramex. If I was a London taxi driver I'd be looking seriously at the Prius, and also the Leaf.

Iceweasel

I think that once a re-gen has started the temperature is raised anyway and all that you need to do is not switch off.

The speed of the vehicle at the time is of little importance I think.

But you may well be right that they have a contract with a DPF cleaning company just as buses and heavy trucks do.

welfayre

Most vehicles have a set procedure for regeneration, usually you need to be driving at high revs (3000rpm or more) for 30-60mins uninterupted. You can force regen some with a diagnostic machine while stationary but again they have conditions such as coolant temp above 90 and exhaust temp above 200, which is relatively hard to maintain while not moving.

Incedently it may not be problem in the future. I read an article recently that said BMW, VW and Merc were really struggling to make a diesel engine capable of meeting Euro emissions targets and that if they continue to increase targets they may not offer a diesel option on vehicles under 2L

atrixblue.-MFR-.

My kia proceed 2013 model regens at speeds over 20mph if the coolant and engine temp are at normal optimum temps i don't turn the engine off or use stop start on short trips usually, and if you stop it will continue the cycle, even if start stop is enabled the ecu will override the start stop feature and turn it off, (hence why people driving the GDI-D diesel version of kia's thinks the start stop kicks in when it wants), when start stop isn't kicking in in my proceed when its enabled and im on average trip or long one with regular stops at junctions etc, ill give it some welly and give it clean out and the stop start will kick back in. i will also do a long trip once a week up the motor way usually a 80-100 mile round trip to keep things balanced.


i know when i have stopped a regen when i get out the car and it smells like burning underneath not quite brake heat smell not quite clutch burn (no i don't ride or burn the clutch) quite honestly say it smells like you've left the ceramic frying pan void of any oil or food on the hob for while.

rev_henry

Sportacus wrote: »

but a London taxi will rarely get above 30mph, not hot enough to burn off the soot, and I can't believe regens are any good for the engine at all (adding fuel to the oil). I suspect the big companies might have agreements with DPF cleaning firms like ceramex. If I was a London taxi driver I'd be looking seriously at the Prius, and also the Leaf.

London taxi drivers (not minicabs) are ONLY allowed to have the TX traditional black cab style vehicle or the Mercedes Vito. Both of which I imagine have been designed to allow the DPF to regenerate round town somehow.

Shaolin_Monkey

welfayre wrote: »

Most vehicles have a set procedure for regeneration, usually you need to be driving at high revs (3000rpm or more) for 30-60mins uninterupted. You can force regen some with a diagnostic machine while stationary but again they have conditions such as coolant temp above 90 and exhaust temp above 200, which is relatively hard to maintain while not moving.

Incedently it may not be problem in the future. I read an article recently that said BMW, VW and Merc were really struggling to make a diesel engine capable of meeting Euro emissions targets and that if they continue to increase targets they may not offer a diesel option on vehicles under 2L

I've seen > 2000 rpm and 20 minutes stated in a manual. 3000 rpm is pretty high for a diesel engine and running at an hour like that would take some doing.