Diesel Particulate Filter - Wish List

[shimon340]

Hello

DPF issues affect all manufacturers and indeed they are there due to the increasingly stringent emissions regulations.

Different manufacuturers handle the DPF system and info given to the customer via the manual and the dashbaord differently. Having worked on these systems and reviewed a number, Volvo's setup is very good.

However, low speed town driving is not a good combination with a DPF. It will clog and will only partially regenerate in service hence why you get the "DPF full" message and the need to firstly drive in a certain way (certain vehicle parameters met) for the in service regeneration to begin and then continue doing so until the procedure ends. Failing to do that, the system will note the degree of filter saturation and the lack of successful in service regenerations and required a bespoke engine programme called a "forced regeneration" ie done by a dealer.

As a manufacturer, the product needs to be in the market to be used by a range of people. Not everyone is mechanically minded. Also, something I once heard was remember how daft the average person is and then recall that half the population are more daft!

The idea of the "% full" DPF display is a good one giving customers the oppotunity to manually start a regeneration themselves at whatever % they like. But again, how many engineering minded customers are there? NB remember the in service regeneration uses a post-combustion fuel dosing to increase fuel vapour in the exhaust to then burn off the particulates in the exhaust. Indeed, the "oven at 600deg" is something we used to do on prototype DPFs. Thats the temperature the carbon particulates oxidise/ignite. Self cleaning ovens work the same way. Ash will be left in the DPF from the fuel and oil additives but NB DPF vehicles have specific engine oil and fuel additives are moving away from inorganic content ie reducing the ash content.

In many ways the DPF design is immature technology and not as yet perfect for its application. But, this affects all manufacturers and was a solution to short timeframe given to meet new emissions targets.

S