DPF - Fire in a can!
A diesel particulate filter (DPF) is a device designed to remove diesel particulate matter or soot from the exhaust gas of a diesel engine. DPF regeneration is the process of burning off the trapped particles so that when the residue emerges, it’s less harmful.
DPF regen process should automatically happen at highway speeds. Sometimes it’s quite passive, seeing as the exhaust heats up and the DPF becomes a little furnace of its own accord. This is called passive regeneration.
All DPFs have a differential pressure sensor that measures the pressure difference across the DPF. As that pressure drop increases, the car knows the filter is getting more and more blocked - because more pressure difference equals more particle load and resistance to flow. Most vehicles in this instance would pre-determined blockage levels and then trigger an active regeneration.
If the driving conditions are right, for example driving at more than about 80km/h on high gear this would typically result in a successful regen, but if you're stuck in traffic in the suburbs, the filter continues to fill up. It throws a warning light and put the car into limp mode.
Towing the vehicle to a dealership for a manual regeneration in a service bay can possibly resolve the issue but it's very very expensive. At Melbourne Euro we have approved chemicals and special software to perform Adaptation on Measured Soot and Calculated Soot levels in order to force a successful DPF regeneration.
EGR - The Diesel that's not fully burned let's try to burn it again!
In Diesel engines, Exhaust Gas Recirculation (EGR) is a nitrogen oxide (NOx) emissions reduction technique. EGR works by recirculating a portion of an engine's exhaust gas back to the engine cylinders. This dilutes the O2 in the incoming air stream and provides gases inert to combustion to act as absorbents of combustion heat to reduce peak in-cylinder temperatures. NOx is produced in high-temperature mixtures of atmospheric nitrogen and oxygen that occur in the combustion cylinder, and this usually occurs at cylinder peak pressure. EGR is a great idea in theory and works great on petrol engines, but on a diesel engine, it can be self-destructive!
Due to the higher combustion temperatures in diesel, larger clearances between pistons, piston rings and bores are required to accommodate for the expanding and contracting of these parts, which is why these motors are prone to excessive blow-by.
Blow-by is the result of pressure building up within the crankcase by the downward force of the pistons. This pressure forces air back up the cylinder and past the gaps between the piston rings and cylinder wall and into the intake chamber.
This blow-by contains traces of engine oil and as the oil gets older, it gets dirtier, heavier and is also diluted with diesel fuel. Combine this mixture in the intake and then add extremely high exhaust temperatures from the recirculating exhaust gasses and you have created diesel “soot”. With the high exhaust temps, the oily blow-by is baked onto the walls of the intake system and over time, you can imagine what happens.
At Melbourne Euro we have the right equipment to replace or clean EGR, adapt EGR valves and actuators to ECU and prevent the vehicle from going into limp mode.
AdBlue - The magical fluid that makes nitrogen oxide disappear!
AdBlue is a Diesel Exhaust Fluid (DEF) and is used to reduce the amount of air pollution created by a diesel engine. Specifically, DEF is an aqueous urea solution made with 32.5% urea and 67.5% deionized water. DEF is consumed in selective catalytic reduction (SCR) that lowers the concentration of nitrogen oxides (NOx) in the diesel exhaust emissions from a diesel engine.
This system relies on the addition of an additive injected into the exhaust stream to lower vehicle emissions. The Adblue injection rate is constantly changing and is controlled by the vehicle's ECU. The amount of Adblue injected is based on many different parameters. these include engine speed, engine load, engine temperature, exhaust gas temperature and exhaust catalyst temperatures.
The additional injection of this Adblue increases the running cost of the vehicle making it unpopular with the vehicle operators. The use of AdBlue fluid on these vehicles gives the vehicle operators major problems should AdBlue not be available in their location, and when the vehicle detects a problem with the Adblue system or if the AdBlue fluid is not used then the vehicle automatically enters a special reduced power mode or completely dead. This mode remains until either the AdBlue system is repaired or bypassed.
At Melbourne Euro we have the right tools, knowledge and experience to resolve any AdBlue problem and get your vehicle running again.
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