All about ADR 80/03 – with Terrain Tamer

Exhaust emissions are very much in the news of late, and different manufacturers have developed their own ways of dealing with the problem.

A diesel particle filter is one type of exhaust treatment used by vehicle manufacturers to comply with ADR 80/03 or Euro5 exhaust emission regulations. At times, this is used in conjunction with exhaust gas recirculation, catalytic convertors and variable geometry turbochargers. A number of small diesels are not yet fitted with diesel particulate filters, possibly due to the cost. Emissions on these vehicles are controlled by convertors and EGR systems. Selective catalytic reduction (SCR) We also have “diesel exhaust fluid” (urea) often known as “Adblue”, injected into the exhaust system to convert the exhaust cases to nitrogen and water.

Diesel particulate filters (DPF)

Diesel particulate filters, when fitted, are used to trap dangerous exhaust particles or “soot”, largely the product of incomplete combustion. Soot quantities vary depending on fuel quality, combustion temperature, engine load, injector condition, engine tune and condition.

Faulty EGR operation is a major contributor to exhaust emissions. Particulate emissions are produced in much larger quantities when an engine is operated at low speed, low load, and low temperature range. Under these conditions a DPF would load up prematurely, requiring a “clean out” or regeneration. There are various ways to keep a filter in good health!

Passive regeneration

First, if the vehicle is operating at the higher load range, higher rev range (2,000–3,000rpm), and the trip times are regularly one hour minimum, then “normal” regeneration is constantly occurring.

Exhaust temperatures of 500-600 degrees C are sufficient to burn out these pesky particles in the diesel particle filter, and convert them by tricky means to water and CO2, and a tiny amount of ash, which mostly accumulates in the filter body.

Vehicles with multi-speed transmissions may cruise at engine revs too low to trigger passive regeneration. It may be necessary to run for 30 minutes in a lower gear periodically to prevent problems down the track.

In some filters the accumulated ash can be cleaned out by specialist firms. Truck engines fitted with larger size filters may cover 500,000km before requiring this service!

Active regeneration

Cooler running, such as idling more than four minutes, stop/start driving, and city deliveries, all contribute to DPF blockage. The engine management unit constantly monitors inlet and outlet pressures of the DPF, and if the indication shows a fault, then an “active” regeneration is started.

To set off regeneration, the temperature in the filter needs to be artificially raised to around 600 degrees C. Manufacturers sometimes just retard the injection timing, causing raw fuel to enter the exhaust system, and the resultant burning raises the temperature high enough to completely burn the soot.

Causing an injector to operate when the exhaust valve is open is another way to introduce raw fuel into the exhaust. Some have an extra injector installed just upstream of the DPF, and use injection (when required) to begin active regeneration. The driver would be unaware of these operations, which would take about 15 minutes.

The above procedure can be inadvertently interrupted by downhill running, idling, switching off, or engine operation that causes exhaust temperature to cool down and upset the regeneration process.

The engine management will try a couple of times to reproduce the temperatures required, but will eventually give up and trigger a dash warning light.

A driver can if possible drive at 3,000rpm for 30 minutes to try to raise exhaust temperature to regenerate the filter, but if not successful should not continue to drive with the light on!

Manual regeneration

Normally done at a workshop (out in the open air) using a scan tool, and following instructions, a regen can be requested, and with scan tool and driving techniques may force a cleanout to rectify the problem.

If the trouble still exists or returns, symptoms such as limp mode being triggered, low performance, poor fuel economy, and warning lights on, then replacement of the DPF is the only option.

Now comes the hard bit. Filters range from $1,000 upwards, so don’t ignore those warning lights!

A cautionary note before discarding the DPF entirely (apart from being illegal), it has proved almost impossible to convince the ECU. that everything is ok.

If a DPF is discarded, a complete remapping of the ECU is generally required! Otherwise symptoms may continue to appear, such as constant shifting into “limp” mode, injection of raw fuel, and severe heat generation in exhaust system.

These symptoms are the result of the ECU attempting to remedy what is registered as a problem.

On some trucks there is even a “DPF missing” fault code!

Things that can show fault code or warning light:

Helpful things to do:

Run vehicle at legal speed twice weekly for at least one hour (metric).

Constant use of fuel additive (suc as Flashlube Common Rail Fuel Additive).

Keep fuel tans full.

Check engine oil for dilution or volume increase due to extra injection during active regeneration attempts.