DVSA has raised the potential to identify via annual testing any removal of or damage to the diesel particulate filter (DPF) fitted to many heavy vehicles. That work could also lead to the detection of tampered-with or defective exhaust gas recirculation (EGR) valves.
Such scope has been publicised in details shared on the Agency’s Moving On blog around its vision and strategy for vehicle testing.
A consultation on the testing process for light vehicles earlier identified that particulate number (PN) testing could be introduced there, and it “could equally apply to heavy vehicles,” says Head of Vehicle Testing Policy Gordon Thomson.
The Agency previously said that PN testing provides “an effective means of identifying removed or damaged DPFs, with significant advantages over current testing methods,” although Mr Thomson notes that thoughts of introducing the process to the vehicle test regime are at an early stage.
The current vehicle test measures smoke density but not the size or quantity of particles. PN testing would enable DVSA “to determine if the vehicle’s emission control system is working as designed – including if a DPF has been damaged or removed,” adds Mr Thomson.
When questioned on how PN testing would sit with EGR function, a DVSA spokesperson says that it would be primarily to check the correct working of the DPF.
“However, as part of the pilot, we will be looking to establish how engine temperature and other factors, such as a defective or tampered-with EGR valve, may influence the result,” they add.
DVSA’s Categorisation of Vehicle Defects manual describes absent or modified emission control equipment as worthy of a delayed prohibition when detected.
The piloting of PN testing for light and heavy vehicles is at “an early stage,” says Mr Thomson, and the exercise will “ensure that any decision on whether to go ahead is as informed as possible.” The impact on vehicle operators and authorised testing facilities (ATFs) will form part of considerations around permanent adoption.
Meanwhile, DVSA is exploring whether driver assist systems could be brought into scope of testing to determine whether they are functioning properly, “ahead of our work on self-driving vehicles,” adds Mr Thomson.
In addition, a review of the “evidence and opportunities” around vehicle testing for operators that are members of Earned Recognition is still to begin, Mr Thomson adds. It follows a call for evidence on the subject that closed in June.
