Quote:
Originally Posted by orbiter
I understand however that all modern diesels do not use a standard DPF and some manufacturers, possibly some Fords, do not remove particulates by burning off the filter deposits, but instead an additive is automatically squirted into the exhaust over a period of time to remove deposits. This additive has to be topped up as a service item. I presume this complies with the latest Euro regs.
Meanwhile, perhaps older euro 3 dieselsare cars that will become more desirable because they are more economical all things considered?
Probably just wishful thinking!
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The additive is held in a separate tank on my V50 just over the axle. When a minimum qty of fuel is put into tank, a measured amount of additive is added to the fuel.
My understanding of this is that it increases exhaust gas temperatures to aid regeneration. My car is a 55 plate 2.0d E4, but as already stated, E3 engines didn't have a DPF and associated control.
There is a pressure differential sensor that measure across the DPF and when the DPF is sensed as being different at input to output, the ecu triggers regeneration.
Under this condition, half the amount of fuel or throttle, is used to make the engine run hotter.
However, newer engines 2.0D may not have a type of DPF filter that requires additive as I believe that there are two types of design for a DPF.
This is the same as the D5 and 2.4D engines where hotter exhaust temperatures negate the need to artificially increase the temp with additive in the fuel.
The type of system employed on my car is the same as the 1.6D so at 75k miles the complete DPF is replaced as a service item.
Interestingly VW and BMW must use a different type of DPF as their cars do not replace the DPF as Volvo do on their smaller engines. Keen observers will note that all VWs emit smoke, some BMW's do but to a lesser degree and all Volvo 2.0 E4 with additive system are smoke free with clean tailpipes.
Incidently, the ford Focus, that uses the same engine in the 2.0ltr, can be ordered with or without DPF.
My car has done 109k miles now and been fully serviced by Volvo. I've never had any issues with the dpf itself, but the pressure differential sensor has been replaced twice as it has caused ecu to trigger limp home mode.
I also believe that it probably affects fuel economy, partly because ecu may be given wrong signals from time to time, but also because the engine wil not breath as well as one with a free flowing exhaust.
To all of you owners that only do a small mileage, my advice would be to take the car down the motorway once in a while. It's good for the exhaust system as a whole, not just the DPF.