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  1. #1
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    Default Cape Town's Diesel Smoke Detectors

    Communique from the City of Cape Town as issued by its Mayco: Health doctor.

    With more than 6000 diesel vehicles emissions tested in the previous financial year, the specialised testing unit is ensuring that motorists keep their emissions in check.

    The emission of dark smoke from vehicles that are using public roads is a contravention of the City’s Air Quality Management By-law.

    The unit was constituted as part of the City’s air quality management plan. It is tasked with ensuring that heavy-duty diesel vehicles comply with the prescribed emission rates.

    Pollution from motor vehicles remains the biggest challenge to ambient air quality. With the continued deterioration in operating conditions of the passenger rail network, many commuters have been forced to rely upon private or public motorised transport. This has further worsened congestion on the road network, but has also resulted in an increase in vehicular emissions.

    In the last financial year, the unit tested 6 268 vehicles, of which just seven failed. Testing statistics were impacted by the hard lockdown from April until June 2020.

    ‘Vehicle emissions are one of the biggest factors impacting air quality, particularly the dark emissions from diesel-powered vehicles. By having the emissions testing unit on hand, the City is able to tackle this issue proactively. However, this is not a punitive exercise – vehicle owners are given an opportunity to fix any problems identified first, and only if they remain non-compliant, is stronger action taken. The unit, through its work, also helps fleet owners keep their vehicles in a good condition,’ said the City’s Mayoral Committee Member for Community Services and Health, Councillor Zahid Badroodien.

    Emissions testing is done at the roadside, in a safely demarcated area, in collaboration with the Cape Town Traffic Service.

    Drivers are requested to put their vehicles in neutral, after which the vehicle temperature is checked. The actual test begins when the driver, or the testing officer, accelerates the vehicle to cut off point, several times, to check the emissions.

    Once the official is satisfied that there are no dark smoke emissions from the vehicle, a certificate of compliance is handed to the driver.

    The City has a range of monitoring and evaluation systems and processes to detect and act on air pollution. This includes an air quality monitoring network that is managed by the Scientific Services Air Quality Laboratories. The network consists of 42 analysers at 13 ambient air quality monitoring stations located across the city. Currently, a process is under way to replace ageing analysers.

    Five years ago, the City also installed a high-powered camera monitoring network on the antennae located on Tygerberg Hills. The Air Quality Management Unit has access to live feeds from this network, which allows for remote monitoring of dark smoke emissions.

    We are satisfied with the rate of compliance, especially considering that when this testing was first started around the turn of the century, the non-compliance rate was at nearly 20 percent. Apart from the proactive testing, factors such as improved engine technology, fleet maintenance and fuel reformulation have also played a role in the increased compliance rates.

    ‘Cape Town is also clearly making an impact, as we have other municipalities conducting visits to assess our programme. Most recently, we had delegates from the eMalahleni Municipality in Mpumalanga join the testing unit to see how things are done,’ added Councillor Badroodien.

    How can the public assist?
    · By ensuring that their vehicles are in sound mechanical condition, and that any excess emissions be addressed timeously
    · By limiting the time spent in their vehicles, where possible, and considering carpooling or alternative modes of transport
    · By reporting vehicles emitting dark smoke to the City’s Air Quality Management Unit on 021 590 5200 during office hours
    · Complaints need to include the details of the person reporting the incident, as well as the details of the offending vehicle (make and registration number), time, date and location of the offence and the direction the vehicle was travelling in
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  2. #2
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    Default Re: Cape Town's Diesel Smoke Detectors

    Ek self het nog nooit een enkele voertuig wat ek besit het tot by die limiter gerev nie. Daar is nie 'n manier tjoppa. Gaan soek vir jou 'n ander kar om te rev.

    Maar om op 'n ordentelike manier toets is ek meer as bereid om my samewerking te gee.
    Last edited by hbannink; 2021/04/18 at 03:50 AM. Reason: Edit to add
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  3. #3
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    Default Re: Cape Town's Diesel Smoke Detectors

    My understanding of the attached text in the first post is that this is aimed at "heavy vehicles" which to me means big trucks. I doubt a normal bakkie or SUV is the vehicle this is aimed at.
    As an "aside" to reving a modern ECU controlled motor. I had a claim against a Fiat dealership for a damaged engine after a cambelt change. They claimed I'd over rev'ed the motor causing the cambelt to jump a tooth or 2 causing the damage. I was able to prove that the motor had never been rev'ed to the limiter by downloading the data from the ECU the records any red line incidents. These could be revs, temperature and any other important parameter. Turned out that the cam pulley nut wasn't correctly torqued allowing the sligh chatter of the pulley to shear the woodruff key.
    Free reving any engine to it's limiter will cause damage. That is why a dyno has load rollers that the drivetrain must work against.
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    Default Re: Cape Town's Diesel Smoke Detectors

    If you don't have a limiter or a tachometer?

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    Default Re: Cape Town's Diesel Smoke Detectors

    Will pay to see these guys test a truck with straight pipes going up the back of the cab...

  6. #6
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    Default Re: Cape Town's Diesel Smoke Detectors

    "heavy-duty diesel vehicles" is my understanding. That is, my tiny motor has never been pulled over for this reason.

    The other point seems to be they have to be belching "dark smoke".

    I know that my ECU logs trouble codes. I haven't found where it logs red line incidents - interested to know which OBDII code will retrieve it.

    I haven't tried testing for a limiter.

    If it helps, the testing equipment looks like this. They'd need a very tall ladder to reach up pipes behind the cab.
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  7. #7
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    Default Re: Cape Town's Diesel Smoke Detectors

    Quote Originally Posted by Butch Dassie View Post
    "heavy-duty diesel vehicles" is my understanding. That is, my tiny motor has never been pulled over for this reason.

    The other point seems to be they have to be belching "dark smoke".

    I know that my ECU logs trouble codes. I haven't found where it logs red line incidents - interested to know which OBDII code will retrieve it.

    I haven't tried testing for a limiter.

    If it helps, the testing equipment looks like this. They'd need a very tall ladder to reach up pipes behind the cab.
    The diagnostic equipment that we used for the overspeed logs was the Fiat unit. I had a friend that was in management at Fiat head office and he believed my story was more credible than the dealerships version. The Fiat diagnostic box and software had a few functions that I couldn't access with the publicly available software that I had.
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  9. #8
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    Default Re: Cape Town's Diesel Smoke Detectors

    I will not pass with my mapped td5..........
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    Default Re: Cape Town's Diesel Smoke Detectors

    I'm remapped and fuelling more now (with a slight increase in EGT), but no noticeable dark smoke.
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    Default Re: Cape Town's Diesel Smoke Detectors

    Quote Originally Posted by Sam vd Merwe View Post
    I will not pass with my mapped td5..........
    The one map that got put on my Td5 increased the black smoke and fuel consumption as well as boost over pressure problems when towing. I then loaded the map I got from Biltong here on the forum. No smoke anymore, good performance and no over boost problems.
    If the fueling is done correctly in the map you shouldn't have excessive black smoke and still have good power.
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    Default Re: Cape Town's Diesel Smoke Detectors

    Me and him got the same map. Under 1500rpm with foot flat its smoking
    Quote Originally Posted by Paul#25 View Post
    The one map that got put on my Td5 increased the black smoke and fuel consumption as well as boost over pressure problems when towing. I then loaded the map I got from Biltong here on the forum. No smoke anymore, good performance and no over boost problems.
    If the fueling is done correctly in the map you shouldn't have excessive black smoke and still have good power.
    Four wheels move the body,
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    Default Re: Cape Town's Diesel Smoke Detectors

    In the diesel motor, you have about 20% excess oxygen in the chamber. Most mappers will exploit this to the maximum resulting in over fuelling at times, such as when not under full load. There's usually a balance point between more fuel for more performance, yet not over fuelling with the resulting black smoke.

    A slight bit more fuel can result in better fuel economy, but this is due to the driver not feeling they have to hit the accelerator as hard.
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    Default Re: Cape Town's Diesel Smoke Detectors

    Good day Guys

    Since u guys are in the know about diesel engines

    Are the wear and tear factors the same as in a petrol engine?

    Valve stem seals piston rings etc?

    I ask coz i have seen black smoke and white smoke from some diesel engines

    Do they mean the same as for petrol engines

    Black - Over fueling

    White - Valve stem seals or piston rings

    How does 1 determine if a diesel engine is still in good condition, this is before purchasing of second hand diesel vehicles.

    If seen many many especially bakkies and double cabs over 300 -400 thousand ks on odometer. and diesel engins are expensive to fix.

    cheers

  15. #14
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    Default Re: Cape Town's Diesel Smoke Detectors

    I'm fairly new to diesels, but I'll start hoping others will correct me or add.

    In general, diesel motors are subjected to higher boost and compression and thus, often already have forged pistons and heavier journals, etc. For this reason, they often outlast piston motors.

    Black smoke (unburnt fuel, soot) is the same – usually over fuelling, but can also indicate no cat / DPF

    White smoke usually indicates water (and usually a slight bit of lube oil) has found its way into the combustion chamber and is being turned into steam. Check the head gasket and head for any cracks. It can also indicate water in the fuel. White smoke at start-up can be expected on cooler mornings due, but it is due to condensation.

    Blue smoke can be due to clogged or restricted engine breather system, but is usually caused by engine oil burning with the fuel. The usual cause is warn valve stem seals and less so, broken piston rings.

    Compression and leak down tests are good tests.
    Last edited by Butch Dassie; 2021/04/19 at 08:15 AM.
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  16. #15
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    Default Re: Cape Town's Diesel Smoke Detectors

    Quote Originally Posted by Butch Dassie View Post
    I'm fairly new to diesels, but I'll start hoping others will correct me or add.

    In general, diesel motors are subjected to higher boost and compression and thus, often already have forged pistons and heavier journals, etc. For this reason, they often outlast piston motors.

    Black smoke (unburnt fuel, soot) is the same – usually over fuelling, but can also indicate no cat / DPF

    White smoke usually indicates water (and usually a slight bit of lube oil) has found its way into the combustion chamber and is being turned into steam. Check the head gasket and head for any cracks. It can also indicate water in the fuel. White smoke at start-up can be expected on cooler mornings due, but it is due to condensation.

    Blue smoke can be due to clogged or restricted engine breather system, but is usually caused by engine oil burning with the fuel. The usual cause is warn valve stem seals and less so, broken piston rings.

    Compression and leak down tests are good tests.
    In diesel engines I have also known white smoke to be caused by fuel starvation.
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  18. #16
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    Default Re: Cape Town's Diesel Smoke Detectors

    Not clear to me what the "pollutants" are? Any particulates, NOx, unburnt hydrocarbons, CO?

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    Default Re: Cape Town's Diesel Smoke Detectors

    As I assume you mean pollutants in reference to this thread, then referring to the City of Cape Town's Air Quality Management By-Law of 2016 and as amended, it states that "air pollutant includes any dust, smoke, fumes or gas that causes or may cause air pollution" where ‘‘air pollution means any change in the environment caused by any substance emitted into the atmosphere from any activity, where that change has an adverse effect on human health or wellbeing or on the composition, resilience and productivity of natural or managed ecosystems, or on materials useful to people, or will have such an effect in the future".

    If I may divulge slightly from this, catalytic converter (CAT), is designed to filter the exhaust gases. By forcing the exhaust gases through the walls between the channels, 85% of the particulate matter (PM10, hydrocarbon combustion by-product and unburnt fuel, soot, black carbon) is trapped / deposited on the walls, so reducing (30% to 95%) the amount of "air pollution". High sulphur content diesel produces more particles. Once the DPF reaches a certain level of ‘saturation’, usually 45%, it performs a regeneration cycle (DPF regen) to burn off the particulate matter inside the filter. This produces even finer diesel particulate matter, which is better able to penetrate lung tissue potentially resulting in an even worse health issue. PM10 can be coughed out, but PM1 can reach the bottom of one’s lungs and remain there. PM1 is undetected by black smoke MOT sniffers. Germany’s TUV (MOT) has decided against DPFs (at least it had the last time I looked at this).
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