Evaluating the efficiency of Diesel Particulate Filters in high-duty vehicles: field operational testing in Portugal

The higher fuel economy allowed by diesel engines in comparison with Otto cycle based engines drove them to a progressive lead in vehicle fleet shares, especially within high-duty fleets, during last years. However, diesel engines have also other less welcome properties such as considerable tailpipe Particulate Matter (PM) emissions that contribute to adverse health effects and also to ecosystems and built heritage degradation. This burden requires straightforward mitigation measures and one of the most frequent in Europe has been the operational use of particle traps in a great diversity of fleets, in particular captive ones. These captive fleets account for an important percentage of annual mileage in urban areas. Nevertheless there’s a lack of information on filters efficiency under real operational conditions as also of an affordable and easily accessible method for doing this evaluation, since the typical methodology for testing particle traps is used only for homologation purposes. Aiming to operationally test Diesel Particulate Filters (DPF) performances using different engine types and emission technologies (EURO standards) tests were implemented in a total of 12 vehicles equipped with 4 different commercially available wall-flow DPF. These tests were done in the two largest Portuguese metropolitan areas, Lisbon and Oporto. Several opacity measurements using the free acceleration test were performed with and without the filter installed for at least 200 running hours per vehicle. Other relevant data (such as fuel consumption) were recorded for evaluating also other possible secondary effects on the vehicle performance. Results indicate an average reduction of 92% in opacity, while no significant changes in fuel consumption and engine power were registered. Conclusions highlight not only the adequacy of the filters tested for PM reduction as well as an inexpensive methodology with potential for ensuring its efficiency in high-duty vehicle fleets real-world operation.

The authors’ team wishes to acknowledge the role of all the partners involved in these DPF systems operational tests, which made all this process possible. Our gratitude to: Camprovis, Dinex, Pirelli, ANTRAM – Associação Nacional de Transportadores Públicos Rodoviários de Mercadorias; ANTROP – Associação Nacional de Transportadores Pesados de Passageiros; AutoChavemor – Inspecções Técnicas de Veículos Automóveis, S.A.; CML – Câmara Municipal de Lisboa; Controlauto, Controlo Técnico Automóvel S.A.; Inspauto – Inspecção de Veículos, Lda.; Inspezalves – Centro Técnico de Inspecções Periódicas a Automóveis, Lda.; IMTT – Instituto de Mobilidade e Transportes Terrestres; Maiambiente – Empresa Municipal do Ambiente da Maia; MasterTest – Inspecção de Veículos (Maia); RL – Rodoviária de Lisboa; STCP – Sociedade de Transportes Colectivos do Porto; TAS Portugal, S.A.; TBOM (Santa Iria de Azóia); TIBA – Transportadora Ideal do Bairro de Alcântara, Lda.; TRACAR – Transportes de Carga e Comércio, SA; Transportes Sardão, S.A. and TST – Transportes Sul do Tejo.

published