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Reduction of Fresh Charge Losses by Selective Exhaust Gas Recirculation (SEGR) in Two-Stroke Engines
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Abstract
It has been well understood that the loss of fresh charge during scavenging process is the principal cause for high specific fuel consumption (sfc) and unburned hydrocarbon (HC) emissions in two stroke, spark ignition engines. A new concept of ‘Selective Exhaust Gas Recirculation (SEGR) has been developed for reduction of these fresh charge losses.
Investigations into the history of fresh charge losses in the exhaust showed that the HC concentration is maximum around top-dead-centre. Recirculation of the portion of the exhaust gases corresponding to the period it contains maximum HC concentration is the basis of SEGR. This could be accomplished by crank case suction. The SEGR system required a recirculation probe in the exhaust connected to the top of transfer passage through a one-way valve. Induction of the fresh charge was similar to that in the conventional engine.
Besides the concept, the paper will discuss the effect of air-fuel ratio, spark-timings and recirculation ratio on performance and emissions. The results compared with and without SEGR showed upto 34% reduction in HC emissions accompanied with about 12% improvements in sfc.
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Saxena, M., Mathur, H., and Radzimirski, S., "Reduction of Fresh Charge Losses by Selective Exhaust Gas Recirculation (SEGR) in Two-Stroke Engines," SAE Technical Paper 891806, 1989, https://doi.org/10.4271/891806.Also In
References
- Davis C.W. “Fuel Injection and Positive Ignition, A Basis for Improved Efficiency and Economy” SAE Trans. 69 120 1961
- Yamagishi G. Sato T. Iwasa H. “A Study of Two-Stroke Cycle Petrol Injection Engine for Exhaust Gas Purification” SAE paper No. 720195
- Vieilledent E. “Low Pressure Electronic Fuel Injection System for Two-Stroke Engines” SAE paper No. 780767
- Yui S. Ohinishi S. “New Concept of Stratified Charge Two-Stroke Engine Yui and Ohinishi Combustion Process (Y O C P)” SAE paper No. 690468
- Kataoha K. Hirako Y. “Improvement Combustion and Clean Exhaust Gas of a Two-Cycle Gasoline Engine With Charge Stratification” Inst. Mech. Engg., C93/75 113 118
- “Pneumatic Fuel Injection Spurs Two-Stroke Revival” Automotive Engineering 1986 94 74
- Duret P. Ecomard A. Audinet M. “A New Two-Stroke Engine With Compressed Air Assisted Fuel Injection for High Efficiency Low Emissions Applications” SAE paper No. 880176
- Batoni G. “An Investigation into the Future of Two-Stroke Motorcycle Engine” SAE paper No.78071
- Blair G.P. Hill B.W. Miller A.J. Nickell S.P. “Reduction of Fuel Consumption of a Spark Ignition Two-Stroke Cycle Engine” SAE paper No. 830093
- Ohinishi S. Sonk Hong JO Pan Do Jo Kato S. “Multilayer Stratified Scavenging (MULS)-A New Scavenging Method for Two-Stroke Engine” SAE paper No. 840420
- Saxena M. Kumar R. Radzirairski S. “Reduction of Mixture Short-Circuiting in Two-Stroke SI Engines: A Novel Design of Intake System” Paper No.B-6, IX NCICEC, IIP Dehradun, India Nov. 1985
- Saxena M. Mathur H.B. Radzi-mirski S. “A Stratified Charging Two-Stroke Engine for Reduction of Scavenged-Through Losses” Small Engine Technology Conference Milwaukee, USA Sept. 1989