Parametric investigation of particulate matter emissions in a gasoline direct injection engine using computational fluid dynamics modelling

ABSTRACT

The effects of start of injection (SOI) timing, spark ignition (SI) timing and exhaust gas recirculation (EGR) rate on particulate matter (PM) emissions in a gasoline direct injection engine are examined through computational fluid dynamics modelling. Varying SOI timing entails compromising between longer mixing time and lower fuel impingement. Delaying the optimal SOI timing by 20 crank angle degree (CAD) results in a 78% increase in number density and a threefold-increase in mass density. PM control benefits from retarding SI timing which prolongs mixing time and shortens soot residence time. A 10 CAD delay from the SI timing at 25 CAD before top dead centre reduces number density and mass density by 65% and 57%, respectively. EGR renders the in-cylinder condition unfavourable for PM formation despite the overall increase in equivalence ratio. For 10% EGR rate, a drop of 547 K in peak temperature decreases number density by 24%. However, mass density increases by a 1.7 factor due to high particle growth species availability.

KEYWORDS:

• CFD
• GDI engine
• particulate matter

Acknowledgments

The Ministry of Higher Education (MOHE) Malaysia is gratefully acknowledged for the financial support towards the study under the Fundamental Research Grant Scheme (FRGS) FRGS/1/2014/TK01/UNIM/01/1.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Ministry of Higher Education, Malaysia [FRGS/1/2014/TK01/UNIM/01/1].

Notes on contributors

Jing Yang Tan

Jing Yang Tan graduated with a PhD in engine research from University of Nottingham Malaysia. He is currently attached to Dyson Malaysia.

Fabrizio Bonatesta

Fabrizio Bonatesta graduated with a PhD in engine research from Nottingham University, UK, and between 2006 and 2008 worked as a Research Fellow for the Engine Research Group there. Between 2008 and 2010, Dr Bonatesta worked as a Senior R&D Engineer at Eminox Ltd, in charge of the CFD function which provided support in the design and optimisation of after-treatment technologies for OEM HD diesel engines. Since 2010, Dr Bonatesta is a permanent member of academic staff at Oxford Brookes University.

Hoon Kiat Ng

Hoon Kiat Ng is Professor of Mechanical Engineering and Head of the Department of Mechanical, Materials and Manufacturing Engineering, University of Nottingham Malaysia. He served as the head of the Energy, Fuel and Power Technology research division, academic champion of the aerospace priority area and the founding deputy director of the Asia Aerospace City Research and Technology Centre.

Suyin Gan

Suyin Gan is currently a Professor of Chemical Engineering at the Department of Chemical and Environmental Engineering, University of Nottingham Malaysia. Prof. Gan works in a wide range of interdisciplinary experimental and computational activities within the central theme of energy and fuels. This includes biofuel cum biomass processing technologies, combustion and emissions as well as environmental remediation.