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Ptero · 10-01-2010, 12:33 AM

Those who understand what we actually burn in our engines will find some value here:

Title: Predicting the behavior of a lean-burn hydrogen-enhanced engine concept
Author: Ivanic, Åziga, 1978-
Other Contributors: Massachusetts Institute of Technology. Dept. of Mechanical Engineering.
Advisor: John B. Heywood.
Department: Massachusetts Institute of Technology. Dept. of Mechanical Engineering.
Publisher: Massachusetts Institute of Technology
Issue Date: 2004
Abstract:
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(cont.) Lean operation of a spark ignition (SI) internal combustion engine (ICE) offers attractive performance incentives. Lowered combustion temperatures inhibit formation of nitrogen oxides (NOx), while reduced intake manifold throttling minimizes pumping losses leading to higher efficiency. These benefits are offset by the reduced combustion speed of lean mixtures, which can lead to high cycle-to-cycle variation and unacceptable engine behavior characteristics. Hydrogen-enhancement can suppress the undesirable consequences of lean operation by accelerating the combustion process, thereby extending the "lean limit." Hydrogen would be produced on-board the vehicle with a fuel reforming device. Since operating an engine in the lean regime requires a significant amount of air, boosting is required. Hydrogen is also an octane enhancer, enabling operation at higher compression ratios, which results in a further improvement in engine efficiency. The focus of this thesis is on the modeling aspect of the lean boosted engine concept. Modeling provides a useful tool for investigating different lean boosted concepts and comparing them based on their emissions and fuel economy. An existing architectural concept has been tailored for boosted, hydrogen-enhanced, lean-bum SI engine. The simulation consists of a set of Matlab models, part physical and part empirical, that have been developed to simulate performance of a real ICE. The model was calibrated with experimental data for combustion and emissions in regards to changes in air/fuel ratio, load and speed, and different reformate fractions. The outputs of the model are NOx emissions and brake specific fuel consumption (BSFC) maps along with the cumulative NOx emissions and fuel economy for the urban
and highway drive cycles.
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Description: Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004.
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Includes bibliographical references (p. 90-91).
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http://dspace.mit.edu/bitstream/hand...pdf?sequence=1
6.314Mb PDF

10-01-2010, 12:33 AM	#17 (permalink)
Ptero Hydrogen Nut Join Date: Oct 2008 Location: California Posts: 152 Smart Car ForTwo Pure - '08 Smart Fortwo Pure stripped 90 day: 51.35 mpg (US) BMW 750iL V12 - '90 BMW V12 90 day: 26.4 mpg (US) Wildfire 250C - '08 Shandong Pioneer 250C Thanks: 2 Thanked 33 Times in 22 Posts	Those who understand what we actually burn in our engines will find some value here: Title: Predicting the behavior of a lean-burn hydrogen-enhanced engine concept Author: Ivanic, Åziga, 1978- Other Contributors: Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Advisor: John B. Heywood. Department: Massachusetts Institute of Technology. Dept. of Mechanical Engineering. Publisher: Massachusetts Institute of Technology Issue Date: 2004 Abstract: -------------------------------------------------------------------------------- (cont.) Lean operation of a spark ignition (SI) internal combustion engine (ICE) offers attractive performance incentives. Lowered combustion temperatures inhibit formation of nitrogen oxides (NOx), while reduced intake manifold throttling minimizes pumping losses leading to higher efficiency. These benefits are offset by the reduced combustion speed of lean mixtures, which can lead to high cycle-to-cycle variation and unacceptable engine behavior characteristics. Hydrogen-enhancement can suppress the undesirable consequences of lean operation by accelerating the combustion process, thereby extending the "lean limit." Hydrogen would be produced on-board the vehicle with a fuel reforming device. Since operating an engine in the lean regime requires a significant amount of air, boosting is required. Hydrogen is also an octane enhancer, enabling operation at higher compression ratios, which results in a further improvement in engine efficiency. The focus of this thesis is on the modeling aspect of the lean boosted engine concept. Modeling provides a useful tool for investigating different lean boosted concepts and comparing them based on their emissions and fuel economy. An existing architectural concept has been tailored for boosted, hydrogen-enhanced, lean-bum SI engine. The simulation consists of a set of Matlab models, part physical and part empirical, that have been developed to simulate performance of a real ICE. The model was calibrated with experimental data for combustion and emissions in regards to changes in air/fuel ratio, load and speed, and different reformate fractions. The outputs of the model are NOx emissions and brake specific fuel consumption (BSFC) maps along with the cumulative NOx emissions and fuel economy for the urban and highway drive cycles. -------------------------------------------------------------------------------- Description: Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2004. -------------------------------------------------------------------------------- Includes bibliographical references (p. 90-91). -------------------------------------------------------------------------------- http://dspace.mit.edu/bitstream/hand...pdf?sequence=1 6.314Mb PDF