Development of a Novel Passive Top–Down Uniflow Scavenged Two-Stroke Gdi Engine
Experimental Thermal and Fluid Science 34 (2010) 217–226
Contents lists available at ScienceDirect
Experimental Thermal and Fluid Science journal homepage: www.elsevier.com/locate/etfs
Development of a novel passive top–down uniflow scavenged two-stroke GDI engine
G. Ciccarelli *, Steve Reynolds, Phillip Oliver
Mechanical and Materials Engineering, Queen’s University, Kingston, Ontario, K7P 2M4 Canada
a r t i c l e
i n f o
a b s t r a c t
The design and performance characteristics of a novel top–down uniflow scavenged gasoline direct-injection two-stroke engine are presented. The novelty of the engine lies in the cylinder head that contains multiple check valves that control scavenging airflow into the cylinder from a supercharged air plenum. When the cylinder pressure drops below the intake plenum pressure during the expansion stroke, air flows into the cylinder through the check valves. During compression the cylinder pressure increases to a level above the intake plenum pressure and the check valves close preventing back-flow into the intake plenum. The engine head design provides asymmetrical intake valve timing without the use of poppet valves and the associated valve-train. In combination with an external Roots-type supercharger that supplies the plenum and exhaust ports at the bottom of the cylinder wall, the novel head provides top–down uniflow air scavenging. Motoring tests indicated that the check valves seal and the peak pressure is governed by the compression ratio. The only drawback observed is that valve closing is delayed as the engine speed increases. In order to investigate the valve dynamics, additional tests were performed in an optically-accessible cold flow test rig that enabled the direct measurement of valve opening and closing time under various conditions. Ó 2009 Elsevier Inc. All rights reserved.
Article history: Received 11 September 2008 Received in revised form 26 October 2009 Accepted 27 October 2009
Keywords:
Contents lists available at ScienceDirect
Experimental Thermal and Fluid Science journal homepage: www.elsevier.com/locate/etfs
Development of a novel passive top–down uniflow scavenged two-stroke GDI engine
G. Ciccarelli *, Steve Reynolds, Phillip Oliver
Mechanical and Materials Engineering, Queen’s University, Kingston, Ontario, K7P 2M4 Canada
a r t i c l e
i n f o
a b s t r a c t
The design and performance characteristics of a novel top–down uniflow scavenged gasoline direct-injection two-stroke engine are presented. The novelty of the engine lies in the cylinder head that contains multiple check valves that control scavenging airflow into the cylinder from a supercharged air plenum. When the cylinder pressure drops below the intake plenum pressure during the expansion stroke, air flows into the cylinder through the check valves. During compression the cylinder pressure increases to a level above the intake plenum pressure and the check valves close preventing back-flow into the intake plenum. The engine head design provides asymmetrical intake valve timing without the use of poppet valves and the associated valve-train. In combination with an external Roots-type supercharger that supplies the plenum and exhaust ports at the bottom of the cylinder wall, the novel head provides top–down uniflow air scavenging. Motoring tests indicated that the check valves seal and the peak pressure is governed by the compression ratio. The only drawback observed is that valve closing is delayed as the engine speed increases. In order to investigate the valve dynamics, additional tests were performed in an optically-accessible cold flow test rig that enabled the direct measurement of valve opening and closing time under various conditions. Ó 2009 Elsevier Inc. All rights reserved.
Article history: Received 11 September 2008 Received in revised form 26 October 2009 Accepted 27 October 2009
Keywords:
References: [1] J.B. Heywood, E. Sher, The Two-Stroke Cycle Engine, Taylor & Francis, Philadelphia, 1999. [2] Stan D. Shawcross, C. Pumphrey, D. Arnall, A five-million kilometre, 100-vehicle fleet trial, of an air-assist direct fuel injected, automotive 2-stroke engine, Presented at SAE World Congress. Detroit, US, 2000. [3] D. Blundell, J. Turner, P. Duret, J. Lavy, J. Oscarsson, G. Emanuelsson, J. Bengtsson, T. Hammarstroem, M. Perotti, R. Kenny, G. Cunningham, Design and evaluation of the ELEVATE two-stroke automotive engine, SAE Paper 200301-0403, 2003. [4] Y. Moriyoshi, M. Arai, J. Katsuta, K. Morikawa, Performance tests of reverse uniflow-type two-stroke gasoline DI engine, Presented at SAE Small Engine Technology Conference & Exposition, Graz, Austria, 2004. [5] M. Tazerout, O. Le Corre, S. Rousseau, TDC determination in IC engines based on the thermodynamic analysis of the temperature–entropy diagram, Presented at the SAE International Spring Fuels & Lubricants Meeting. Dearborn, MI, USA, 1999. [6] P. Oliver, S. Reynolds, G. Ciccarelli, Flowbench calibration of a numerical model for a novel uniflow-scavenged two-stroke GDI engine, Presented at SAE Power Train Conference, Toronto, 2006. [7] J.B. Heywood, Internal Combustion Engine Fundamentals, McGraw-Hill, 1988.