Experience of Fitting London Black Cabs with Fuel Borne Catalyst Assisted Diesel Particulate Filters - Part 2 Non-Regulated Emissions Measurements

Forthcoming emissions legislation is driving the passenger car manufacturers towards the fitting of Diesel Particulate Filters (DPFs) as original equipment. In areas with a particular problem such as heavily congested city centres, retrospective legislation has also been introduced, for example in Hong Kong and Tokyo. Legislation mandating the retrofitting of DPFs obviously has an immediate effect on particulate emissions. Other authorities are thus investigating the efficacy of such measures.

However with the increasing use of DPF technology concerns are now being raised over some currently unregulated emissions such as ultra fine particulate and NO₂, although total particulate mass and oxides of nitrogen are regulated.

To add to the data base for such issues a programme of work was run using London Black Cabs. Four cars were fitted with a DPF, an on-board dosing system to meter a fuel borne catalyst (FBC) into the fuel and a data logger to monitor the DPF performance. Emissions measurements were taken before and after fitting the DPF. The cars were then run on the road conducting normal taxi duties.

This paper presents an analysis of the results of some non-regulated emissions testing including particle size analysis and NO_X speciation. A companion paper describes the results of the regulated emissions testing plus the operation aspects of the programme.