Change search
ReferencesLink to record
Permanent link

Direct link
Flow effects due to valve and piston motion in an internal combustion engine exhaust port
KTH, School of Engineering Sciences (SCI), Mechanics, Fluid Mechanics of Industrial Processes. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).ORCID iD: 0000-0001-7715-863X
Northwestern Polytechnical University. (National Key Laboratory of Aerodynamic Design and Research)
KTH, School of Engineering Sciences (SCI), Mechanics. KTH, School of Industrial Engineering and Management (ITM), Centres, Competence Center for Gas Exchange (CCGEx).ORCID iD: 0000-0001-7330-6965
2015 (English)In: Energy Conversion and Management, ISSN 0196-8904, E-ISSN 1879-2227, Vol. 96, 18-30 p.Article in journal (Refereed) Published
Abstract [en]

Performance optimization regarding e.g. exhaust valve strategies in an internal combustion engine is often performed based on one-dimensional simulation investigation. Commonly, a discharge coefficient is used to describe the flow behavior in complex geometries, such as the exhaust port. This discharge coefficient for an exhaust port is obtained by laboratory experiments at fixed valve lifts, room tem- peratures, and low total pressure drops. The present study investigates the consequences of the valve and piston motion onto the energy losses and the discharge coefficient. Therefore, Large Eddy Simulations are performed in a realistic internal combustion geometry using three different modeling strategies, i.e. fixed valve lift and fixed piston, moving piston and fixed valve lift, and moving piston and moving valve, to estimate the energy losses. The differences in the flow field development with the different modeling approaches is delineated and the dynamic effects onto the primary quantities, e.g. discharge coefficient, are quantified. Considering the motion of piston and valves leads to negative total pressure losses during the exhaust cycle, which cannot be observed at fixed valve lifts. Additionally, the induced flow structures develop differently when valve motion is taken into consideration, which leads to a significant disparity of mass flow rates evolving through the two individual valve ports. However, accounting for piston motion and limited valve motion, leads to a minor discharge coefficient alteration of about one to two percent. 

Place, publisher, year, edition, pages
Elsevier, 2015. Vol. 96, 18-30 p.
Keyword [en]
Internal combustion engines, Fuel economy, Turbocharged engines, Exhaust gas energy, Large Eddy Simulation
National Category
Fluid Mechanics and Acoustics
Research subject
Vehicle and Maritime Engineering
URN: urn:nbn:se:kth:diva-161210DOI: 10.1016/j.enconman.2015.02.058ISI: 000353729200003ScopusID: 2-s2.0-84924262331OAI: diva2:794013
Swedish Energy Agency

QC 20150311

Available from: 2015-03-10 Created: 2015-03-10 Last updated: 2015-11-17Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopusSciencedirect

Search in DiVA

By author/editor
Semlitsch, BernhardMihaescu, Mihai
By organisation
Fluid Mechanics of Industrial ProcessesCompetence Center for Gas Exchange (CCGEx)Mechanics
In the same journal
Energy Conversion and Management
Fluid Mechanics and Acoustics

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 88 hits
ReferencesLink to record
Permanent link

Direct link