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Valve Timing for Control of Oxides of Nitrogen (NOx)
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English
Abstract
Three engine camshaft approaches to the reduction of oxides of nitrogen were investigated: increased valve overlap, variable camshaft timing, and variable valve overlap. The interaction of these systems with emissions, fuel consumption, and power was evaluated on a dynamometer engine. The effects of air-fuel ratio and exhaust backpressure were also reported. Results of the dynamometer study were verified with vehicle tests.
Oxides of nitrogen levels of 1.2-2.0 g/mile were attained through camshaft design with acceptable drivability on the 1970 federal test procedure.
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Citation
Freeman, M. and Nicholson, R., "Valve Timing for Control of Oxides of Nitrogen (NOx)," SAE Technical Paper 720121, 1972, https://doi.org/10.4271/720121.Also In
References
- Benson J. D. Stebar R. F. “Effects of Charge Dilution on Nitric Oxide Emission from a Single-Cylinder Engine.” Paper 710008 SAE Automotive Engineering Congress Detroit January 1971
- Meacham G. B. Kirby “Variable Cam Timing as an Emission Control Tool.” Paper 700673 SAE Automotive Engineering Congress Detroit January 1971
- “Control of Air Pollution from New Motor Vehicles and New Motor Vehicle Engines,” Federal Register 23 108 June 4 1968
- “Control of Air Pollution from New Motor Vehicles and New Motor Vehicle Engines.” Federal Register 35 219 November 10 1970
- Engine Terminology and Nomenclature SAE J604c. SAE Recommended Practice, SAE Handbook
- Daniel W. A. “Engine Variable Effects on Exhaust Hydrocarbon Formations (Single Cylinder Engine Study with Propane as Fuel).” SAE Transactions 76 paper 670124
- Siewart R. M. “How Individual Valve Timing Events Affect Exhaust Emissions.” Paper 710609 SAE Mid-Year Meeting Montreal June 1971