Diesel Particulate Filter Regeneration with On-Board Produced Hydrogen-Rich Gas

Lead Research Organisation: University of Birmingham
Department Name: Mechanical Engineering

Abstract

The proposed research is part of a research study on the development of a diesel engine emissions reduction system with enhanced performance by utilisation of hydrogen produced on-board by exhaust gas fuel reforming. The research is motivated by the requirement of diesel engines to meet future emission regulations and by the potential of on-board exhaust gas fuel reforming to provide a way of improving diesel combustion and emissions as well as increasing the efficiency of diesel engine aftertreatment devices.The system targets are to achieve HC, CO and particulate matter (PM) emissions reduction of >90% using a diesel oxidation catalyst (DOC) and a diesel particulate filter (DPF), respectively, and NOx reduction of >70% using lean NOx catalyst technology (HC-SCR or NH3-SCR or NOx trap). The system will have to be cost effective (i.e. use of base metal catalyst or reduced precious metal catalyst content) and should operate without the need of specific engine map development.Specifically, the purpose of the present proposal is to extent the scientific knowledge on PM aftertreatment assisted by reformate addition that will allow successful integration of the DPF and reforming technologies.The study unfolds into two main parts: i) investigation of the use of reformate to promote the soot oxidation and hence improve the DPF regeneration at low exhaust gas temperatures (Brunel University) and ii) investigation of the improvement of DPF regeneration by soot oxidation with NO2 achieved through promotion of the low temperature NO to NO2 conversion rates in a DOC situated upstream of the DPF by addition of small quantities of reformate (University of Birmingham).By extending the understanding of the fundamental processes occurring during NO oxidation and filter regeneration, new catalysts and catalytic systems will be designed and guidelines for the further stages of the research programme towards a full working diesel engine - fuel reformer - aftertreatment system will be developed.

Publications

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Gill S (2011) Analysis of reformed EGR on the performance of a diesel particulate filter in International Journal of Hydrogen Energy

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Lau C (2011) Biogas upgrade to syn-gas (H2-CO) via dry and oxidative reforming in International Journal of Hydrogen Energy

 
Description The major long term challenge for the automotive industry is the substantial reduction of greenhouse gas emissions (i.e. CO2) with a simultaneous reduction in all other regulated emissions. Although local pollutant emissions (specifically NOx, CO, HC and soot) are already being addressed through the use of aftertreatment systems and higher quality fuels, new emission standards that have been enforced are more stringent, especially on NOx and particulate matter (PM) emissions and CO2 . The diesel particulate filter technology has been established as a favourable method and a necessity for the control of diesel PM emissions.

In an ongoing work we are in the stage of developing a diesel engine emissions reduction system with enhanced performance by utilising hydrogen produced on-board in an exhaust gas assisted diesel fuel reformer. This type of fuel reforming process involves the on-board generation of hydrogen-containing gas by direct catalytic interaction of hydrocarbon fuels with engine exhaust gases.

The initial aim of this work was to design a fuel reformer-Continuously Regenerated Trap (CRT)- diesel particulate filter (DPF) system. The produced reformate (i.e. H2-rich gas), was introduced continuously into the DOC part of the CRT-DPF or directly to the catalyst coated DPF, when required (i.e. low load, low exhaust temperatures) in small concentrations in order to enhance NO to and NO2 oxidation. Results using a CRT-DPF aftertreatment system showed promotion of the NO to NO2 oxidation over the DOC is achieved, at low hydrogen additions (i.e. 500 - 2000 ppm). The increased NO2 concentration in the exhaust improved the soot oxidation at low temperatures and helped in maintaining a soot free DPF, as seen from the temperature changes and pressure drop trends along the filter. This leads to improved engine fuel consumption and reduced CO2 as less fuel is required for the DPF regeneration.

Experimental investigation of the effects of hydrogen addition on the periodic regeneration of a DPF not coated with catalyst was also carried out. These tests were performed at different temperatures with addition of metered quantities of hydrogen or simulated reformate to the exhaust gas flow upstream of the DPF. The results indicated that addition of quantities of hydrogen that result in hydrogen concentrations in the DPF feed gas in the range of 3-4 % (vol.) was required to assist the combustion of the accumulated soot by increasing the temperature.

The aim of the project was expanded and the ignition characteristics, combustion process and exhaust gas emissions from the engine operation on dual fuel (diesel and reformate) at low load engine operation, were examined. The incorporation of a diesel oxidation catalyst Pt/Al2O3 in the engine exhaust for the oxidation of NO, CO and H2 has also been investigated. Significant improvements in the engine NOx-Smoke trade-off and gaseous fuel (H2 - CO) utilization were obtained without penalty in fuel consumption, when reformate used for combustion. The incorporation of a Pt/Al2O3 oxidation catalyst in the engine exhaust can utilise both H2 and CO emission to promote the NO to NO2 oxidation in the engine exhaust.
Exploitation Route As explained in the exploitation section, the work is currently under consideration from industry (i.e. automotive related OEMs and tier suppliers). The systems that are currently under development have potential to be used directly by the industrial partners who supported the initial work (i.e. EPSRC funded) but also the industrial partners (including Ford, Jaguar Land Rover, Johnson Matthey, Cambustion, Revolve, ITM), part of large consortium in a joint project funded by TSB. Furthermore other potential users are the engine and aftertreatment catalyst manufacturers and researchers that will be able to use the obtained results and systems to develop future automotive catalysts and engine systems. This in turn will benefit the society and the environment due to reduced exhaust emissions. As controlling of diesel engine emissions is receiving increasing attention of research by almost all the automotive companies in the world, it would be beneficial to the UK economy if the proposed techniques in the present proposal come into production first by the UK industry. As described in the exploitation part of the proposal stage it was estimated that the techniques researched and demonstrated in this project will finally reach industry prototype state in a few years time. Currently outcomes of this research work are under further research and development with industry. More specifically this has been considered as a work package in a TSB funded project where Birmingham is partners in a consortium of 2 OEM's (Ford and Jaguar Land Rover), 1 catalyst manufacturer (Johnson Matthey was also the industrial partner in the original EPSRC funded project) and 3 more SME's. This implies that significant exploitation of the technology through active promotion by world leading in their fields industrial partners is under way as part of their commercial business development within the automotive industry.
Findings will also be used in a new EU funded project will 14 partners, including Industry and partners from USA.
Sectors Chemicals,Education,Energy,Environment,Transport

 
Description There is a range of findings that have been documented in Journal Publications and peer reviewed conferences. The findings have also been presented to the industrial partners supported or involved during the research. In addition the findings have been presented to other academic collaborators and industrial partners. After the end of the EPSRC grant the idea attracted interest from industry. The idea formed a wor package in a TSB proposal that was funded "project name CREO" , was led by Ford Motor Company with partners including Jaguar land Rover, Johnson Matthey, Cambustion, Revolve, ITM Power and two more univeresitites. The system still under investigation by the OEM's but there are still challenges to overcome. The outcome of this research has also been used by other researchers to aid them with experimental studies, development studies and modelling. Findings have also been presented in lecture to BEng and MEng students.
First Year Of Impact 2012
Sector Education,Energy,Environment,Transport
Impact Types Societal,Economic

 
Description Industry funded project
Amount £125,000 (GBP)
Organisation Johnson Matthey 
Department Johnson Matthey Technology Centre
Sector Private
Country United Kingdom
Start 10/2010 
End 10/2016
 
Description Industry funding
Amount £12,000 (GBP)
Organisation Virgin Rail Group 
Sector Private
Country Unknown
Start 04/2015 
End 08/2015
 
Description Industry funding
Amount £15,000 (GBP)
Organisation G-Volution 
Sector Private
Country United Kingdom
Start 03/2014 
End 05/2014
 
Description Ford Motor Company 
Organisation Ford Motor Company
Country United States 
Sector Private 
PI Contribution Knowledge transfer from our research into their products, advice on systems they are developing.
Collaborator Contribution In kind contribution such as modern engines, engine components, other hardware for engine control, man power, advice on research guidelines
Impact - Scientific Publications - Innovate UK project (CREO) - Disciplines involved: Chemistry, Engineering, Environmental Science, Physics.
Start Year 2010
 
Description Johnson Matthey Plc 
Organisation Johnson Matthey
Country United Kingdom 
Sector Private 
PI Contribution Research to inform the company in understanding the effect of gaseous and particulate emissions on the after treatment systems designed by the Company. Our research has helped the company to improve their products when required but also has helped them to improve their experimental facilities in developing their catalysts. Our work has also helped the company to understand how some of their catalysts are performing under realising conditions seen in an engine environment. We have generated new knowledge that transferred to the company to understand the nature of the emissions from modern engine but also from alternative sustainable fuels.
Collaborator Contribution The partner has contributed through in-kind and cash contribution to support the experimental work. They have also provided us with knowledge and advice on the catalysts and chemistry side of the project.
Impact There are several outputs that are currently in review or in preparation. So far we have published the following one. -Bogarra-Macias, M., Herreros-Arellano, J., Tsolakis, A., York, A. et al., "Reformate Exhaust Gas Recirculation (REGR) Effect on Particulate Matter (PM), Soot Oxidation and Three Way Catalyst (TWC) Performance in Gasoline Direct Injection (GDI) Engines," SAE Int. J. Engines 9(1):2016, doi:10.4271/2015-01-2019. - Poster presentation with title "On-bard Reforming Effect in PM for GDI engines" that led in winning and Award for the best poster in the SAE2014 International Powertrain, Fuels&Lubricants. - Johnson Matthey Academic Conference 2014 and 2015, poster presentations - Future power train conference, Solihull February 2015, Title: Study of PM and Gaseous Emissions in GDI engine Using On-bard Reforming
Start Year 2008
 
Description International Workshop (Bonn, Germany) 
Form Of Engagement Activity Participation in an activity, workshop or similar
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact Workshop on technologies that can improve emissions from road transport vehicles. This was a two hours interactive workshop.
Year(s) Of Engagement Activity 2016
URL http://www.emission-control-gasoline.com/MM