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Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
The objective of the University consortium was to investigate the fundamental processes that determine the practical boundaries of Low Temperature Combustion (LTC) engines and develop methods to extend those boundaries to improve the fuel economy of these engines, while operating with ultra low emissions. This work involved studies of thermal effects, thermal transients and engine management, internal mixing and stratification, and direct injection strategies for affecting combustion stability. This work also examined spark-assisted Homogenous Charge Compression Ignition (HCCI) and exhaust after-treatment so as to extend the range and maximize the benefit of Homogenous Charge Compression Ignition (HCCI)/ Partially Premixed Compression Ignition (PPCI) operation. In summary the overall goals were; Investigate the fundamental processes that determine the practical boundaries of Low Temperature Combustion (LTC) engines; Develop methods to extend LTC boundaries to improve the fuel economy of HCCI engines fueled on gasoline and alternative blends, while operating with ultra low emissions; and Investigate alternate fuels, ignition and after-treatment for LTC and Partially Premixed compression Ignition (PPCI) engines.
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
The objective of the University consortium was to investigate the fundamental processes that determine the practical boundaries of Low Temperature Combustion (LTC) engines and develop methods to extend those boundaries to improve the fuel economy of these engines, while operating with ultra low emissions. This work involved studies of thermal effects, thermal transients and engine management, internal mixing and stratification, and direct injection strategies for affecting combustion stability. This work also examined spark-assisted Homogenous Charge Compression Ignition (HCCI) and exhaust after-treatment so as to extend the range and maximize the benefit of Homogenous Charge Compression Ignition (HCCI)/ Partially Premixed Compression Ignition (PPCI) operation. In summary the overall goals were; Investigate the fundamental processes that determine the practical boundaries of Low Temperature Combustion (LTC) engines; Develop methods to extend LTC boundaries to improve the fuel economy of HCCI engines fueled on gasoline and alternative blends, while operating with ultra low emissions; and Investigate alternate fuels, ignition and after-treatment for LTC and Partially Premixed compression Ignition (PPCI) engines.
Author: Rakesh Kumar Maurya Publisher: Springer ISBN: 3319685082 Category : Technology & Engineering Languages : en Pages : 553
Book Description
This book deals with novel advanced engine combustion technologies having potential of high fuel conversion efficiency along with ultralow NOx and particulate matter (PM) emissions. It offers insight into advanced combustion modes for efficient utilization of gasoline like fuels. Fundamentals of various advanced low temperature combustion (LTC) systems such as HCCI, PCCI, PPC and RCCI engines and their fuel quality requirements are also discussed. Detailed performance, combustion and emissions characteristics of futuristic engine technologies such as PPC and RCCI employing conventional as well as alternative fuels are analyzed and discussed. Special emphasis is placed on soot particle number emission characterization, high load limiting constraints, and fuel effects on combustion characteristics in LTC engines. For closed loop combustion control of LTC engines, sensors, actuators and control strategies are also discussed. The book should prove useful to a broad audience, including graduate students, researchers, and professionals Offers novel technologies for improved and efficient utilization of gasoline like fuels; Deals with most advanced and futuristic engine combustion modes such as PPC and RCCI; Comprehensible presentation of the performance, combustion and emissions characteristics of low temperature combustion (LTC) engines; Deals with closed loop combustion control of advanced LTC engines; State-of-the-art technology book that concisely summarizes the recent advancements in LTC technology. .
Author: Prabhat Ranjan Jha Publisher: ISBN: Category : Electronic dissertations Languages : en Pages : 313
Book Description
It's crucial to use advanced combustion strategies to increase efficiency and decrease engine-out pollutants because of the compelling need to reduce the global carbon footprint. This dissertation proposes dual fuel low-temperature combustion as a viable strategy to decrease engine-out emissions and increase the thermal efficiency of future heavy-duty internal combustion (IC) engines. In dual fuel combustion, a low reactivity fuel (e.g. methane, propane) is ignited by a high reactivity fuel (diesel) in a compression-ignited engine. Generally, the energy fraction of low reactivity fuel is maintained at much higher levels than the energy fraction of the high reactivity fuel. For a properly calibrated engine, combustion occurs at lean and low-temperature conditions (LTC). This decreases the chances of the formation of soot and oxides of nitrogen within the engine. However, at low load conditions, this type of combustion results in high hydrocarbon and carbon monoxide emissions. The first part of this research experimentally examines the effect of methane (a natural gas surrogate) substitution on early injection dual fuel combustion at representative low loads of 3.3 and 5.0 bar BMEPs in a single-cylinder compression ignition engine (SCRE). Gaseous methane fumigated into the intake manifold at various methane energy fractions was ignited using a high-pressure diesel pilot injection at 310 CAD. Cyclic combustion variations at both loads were also analyzed to obtain further insights into the combustion process and identify opportunities to further improve fuel conversion efficiencies at low load operation. In the second part, the cyclic variations in dual fuel combustion of three different low reactivity fuels (methane, propane, and gasoline) ignited using a high-pressure diesel pilot injection was examined and the challenges and opportunities in utilizing methane, propane, and gasoline in diesel ignited dual fuel combustion, as well as strategies for mitigating cyclic variations, were explored. Finally, in the third part a CFD model was created for diesel methane dual fuel LTC. The validated model was used to investigate the effect of methane on diesel autoignition and various spray targeting strategies were explored to mitigate high hydrocarbon and carbon monoxide emissions at low load conditions.
Author: James S Harris Publisher: ISBN: Category : Electronic dissertations Languages : en Pages : 0
Book Description
Internal combustion engines are a key aspect of society, and their continued use poses challenges from an environmental standpoint since they emit pollutant and greenhouse gas emissions. This dissertation focuses on experimental analysis of dual-fuel low temperature combustion (LTC), which can be used as a strategy to reduce engine-out emissions and increase engine efficiencies. Dual fuel LTC uses two different fuels, a high reactivity fuel (HRF) and a low reactivity fuel (LRF). The HRF has a higher cetane number than the LRF, which allows for easier auto-ignition in compression ignition engines. Dual fuel engines also utilize high air to fuel ratios to achieve LTC. This, combined with early injection timings of the HRF, helps to reduce oxides of nitrogen (NOx) emissions. At low load conditions, this is a problem since higher cycle-to-cycle variations can increase pollutants such as unburned hydrocarbons (UHC) and carbon monoxide (CO). To combat this, a firm understanding of dual fuel LTC is required, as well as a strategy for reducing the cycle-to-cycle variations. The first part of this work further identifies a combustion heat release 'transformation region' across different HRF injection timings wherein in-cylinder conditions arise that are conducive for ultra-low NOx emissions. This phenomenon occurs for different IC engine platforms and different fueling combinations. An experimental analysis, 0D chemical kinetic analysis, and 3D computation fluid dynamic (CFD) analysis were combined to elucidate the underlying causes for this phenomenon. The local stratification level of the fuel/air mixture was identified as the likely cause of combustion heat release transformation with changing HRF injection timing. The second part of the present work builds upon the findings of the first part by utilizing local stratification to mitigate cycle-to-cycle variations that are present at low loads. A framework of experiments was formulated for both a low engine load of 5 bar gross indicated mean effective pressure (IMEPg) and a high load of 15 bar IMEPg, wherein an injection strategy concept termed Spray TArgeted Reactivity Stratification (STARS) was utilized using both diesel and Polyoxymethelene-dimethyl-ether (POMDME) as HRFs. A steep decrease in UHC and CO emissions (> 80% reductions) as well as improved engine operation stability were demonstrated using both HRFs with dual fuel LTC at 5 bar IMEPg. Further, potential for emissions mitigation and efficiency improvement are discussed, as well as differences in the experimental results shown between the differing HRFs.
Author: United States. Congress. House. Committee on Appropriations. Subcommittee on Department of the Interior and Related Agencies Publisher: ISBN: Category : United States Languages : en Pages : 592
Author: Publisher: ISBN: Category : Languages : en Pages :
Book Description
The key to overcome Low Temperature Combustion (LTC) load range limitations in reciprocating engines is based on proper control over the thermo-chemical properties of the in-cylinder charge. The studied alternative to achieve the required control of LTC is the use of two separate fuel streams to regulate timing and heat release at specific operational points, where the secondary fuel is a reformed product of the primary fuel in the tank. It is proposed in this report that the secondary fuel can be produced using exhaust heat and Thermo-Chemical Recuperation (TCR). TCR for reciprocating engines is a system that employs high efficiency recovery of sensible heat from engine exhaust gas and uses this energy to transform fuel composition. The recuperated sensible heat is returned to the engine as chemical energy. Chemical conversions are accomplished through catalytic and endothermic reactions in a specially designed reforming reactor. An equilibrium model developed by Gas Technology Institute (GTI) for heptane steam reforming was applied to estimate reformed fuel composition at different reforming temperatures. Laboratory results, at a steam/heptane mole ratio less than 2:1, confirm that low temperature reforming reactions, in the range of 550 K to 650 K, can produce 10-30% hydrogen (by volume, wet) in the product stream. Also, the effect of trading low mean effective pressure for displacement to achieve power output and energy efficiency has been explored by WVU. A zerodimensional model of LTC using heptane as fuel and a diesel Compression Ignition (CI) combustion model were employed to estimate pressure, temperature and total heat release as inputs for a mechanical and thermal loss model. The model results show that the total cooling burden on an LTC engine with lower power density and higher displacement was 14.3% lower than the diesel engine for the same amount of energy addition in the case of high load (43.57mg fuel/cycle). These preliminary modeling and experimental results suggest that the LTC-TCR combination may offer a high efficiency solution to engine operation. A single zone model using a detailed chemical kinetic mechanism was implemented in CHEMKIN and to study the effects of base fuel and steam-fuel reforming products on the ignition timing and heat release characteristics. The study was performed considering the reformed fuel species composition for total n-heptane conversion (ideal case) and also at the composition corresponding to a specific set of operational reforming temperatures (real case). The computational model confirmed that the reformed products have a strong influence on the low temperature heat release (LTHR) region, affecting the onset of the high temperature heat release (HTHR). The ignition timing was proportionally delayed with respect to the baseline fuel case when higher concentrations of reformed gas were used. For stoichiometric concentration of RG, it was found that by increasing the proportion of reformed fuel to total fuel (RG), from 0% to 30%, the amount of energy released during the LTHR regime, or HR{sub L}, was reduced by 48% and the ignition timing was delayed 10.4 CA degrees with respect to the baseline fuel case. For RG composition corresponding to certain operational reforming temperatures, it was found that the most significant effects on the HCCI combustion, regarding HR{sub L} reduction and CA50 delay, was obtained by RG produced at a reforming temperature range of 675 K-725 K.
Author: United States. Congress. House. Committee on Appropriations. Subcommittee on Department of the Interior and Related Agencies Publisher: ISBN: Category : United States Languages : en Pages : 596
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Author: Rakesh Kumar Maurya
Author: Prabhat Ranjan Jha
Author: James S Harris
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Author: United States. Congress. House. Committee on Appropriations. Subcommittee on Department of the Interior and Related Agencies
Author: United States. Office of Fossil Energy
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Author: 
Author: United States. Congress. House. Committee on Appropriations. Subcommittee on Department of the Interior and Related Agencies