Download or read book High Efficiency RCCI Combustion written by and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental investigation of the pragmatic limits of Reactivity Controlled Compression Ignition (RCCI) engine efficiency was performed. The study utilized engine experiments combined with zero-dimensional modeling. Initially, simulations were used to suggest conditions of high engine efficiency with RCCI. Preliminary simulations suggested that high efficiency could be obtained by using a very dilute charge with a high compression ratio. Moreover, the preliminary simulations further suggested that with simultaneous 50% reductions in heat transfer and incomplete combustion, 60% gross thermal efficiency may be achievable with RCCI. Following the initial simulations, experiments to investigate the combustion process, fuel effects, and methods to reduce heat transfer and incomplete combustion reduction were conducted. The results demonstrated that the engine cycle and combustion process are linked, and if high efficiency is to be had, then the combustion event must be tailored to the initial cycle conditions. It was found that reductions to engine heat transfer are a key enabler to increasing engine efficiency. In addition, it was found that the piston oil jet gallery cooling in RCCI may be unnecessary, as it had a negative impact on efficiency. Without piston oil gallery cooling, it was found that RCCI was nearly adiabatic, achieving 95% of the theoretical maximum cycle efficiency (air standard Otto cycle efficiency).

Download or read book High Efficiency Low Emissions RCCI Combustion by Use of a Fuel Additive written by Derek Splitter and published by . This book was released on 2010 with total page 15 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book High Power Output Operation of RCCI Combustion written by and published by . This book was released on 2015 with total page 219 pages. Available in PDF, EPUB and Kindle. Book excerpt: A computational investigation of methods to extend the upper limit of power output of reactivity controlled compression ignition (RCCI) engines was performed. The study utilized two approaches. The first approach is to increase the engine speed while maintaining a medium load. The second approach is to operate at higher loads without changing the engine speed. Iso-octane and n-heptane were used to represent the low-reactivity fuel and high-reactivity fuel, respectively. A light-duty diesel engine was modeled for the high speed dual-fuel RCCI combustion study. With high-speed operation several benefits were identified. Firstly, the peak pressure rise rates (PPRR), both crank angle-based and time-based, were reduced compared to those with low-speed operation. Secondly, at high speed the NO formation residence time became short, leading to reduced NOx emissions. Lastly, a frictional penalty analysis of high-speed operation using the Chen-Flynn model was conducted, which showed only 0.5 bar FMEP increase compared to that at low-speed. These findings indicate that high-speed RCCI is a very promising path for high-power output operation. For the high-load operation study use of dual direct-injectors was explored in order to direct-inject both fuels. Analysis of the optimum injection strategy revealed two main physical mechanisms enabling high-load operation with dual direct-injectors. The first exploited local evaporative cooling from the iso-octane injection, which delayed the iso-octane ignition. The second mechanism was related to the shorter chemical residence time of the iso-octane due to its late delivery into the cylinder. It was also noted that n-heptane's role as an ignition source could not be achieved with just iso-octane. Finally, the co-axial injector location assumption was removed by using an actual dual-injector layout. Unlike results with the co-axial injector design, the actual dual-injector layout exhibited soot and CO emission problems. In order to attempt to accommodate off-center injector locations, various injector hole patterns were tested. Although these unconventional injector hole patterns improved the emissions, it is concluded that the development of a co-axial dual-fuel injector is imperative in order to achieve clean RCCI combustion at high load.

Download or read book A Pathway to Higher Efficiency Internal Combustion Engines Through Thermochemical Recovery and Fuel Reforming written by Flavio Dal Forno Chuahy and published by . This book was released on 2018 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dual fuel reactivity controlled compression ignition (RCCI) combustion is a promising method to achieve high efficiency with near zero NOx and soot emissions; however, the requirement to carry two fuels on-board has limited practical applications. Advancements in catalytic reforming have demonstrated the ability to generate syngas (a mixture of CO and hydrogen) from a single hydrocarbon stream. The reformed fuel mixture can then be used as a low reactivity fuel stream to enable RCCI out of a single parent fuel. Beyond enabling dual-fuel combustion strategies out of a single parent fuel, fuel reforming can be endothermic and allow recovery of exhaust heat to drive the reforming reactions, potentially improving overall efficiency of the system. Previous works have focused on using reformed fuel to extend the lean limit of spark ignited engines, and enhancing the control of HCCI type combustion. The strategy pairs naturally with advanced dual-fuel combustion strategies, and the use of dual-fuel strategies in the context of on-board reforming and energy recovery has not been explored. Accordingly, the work presented in this dissertation attempts to fill in the gaps in the current literature and provide a pathway to "single" fuel RCCI combustion through a combination of experiments and computational fluid dynamics modeling. Initially, a system level analysis focusing on three common reforming techniques (i.e., partial oxidation, steam reforming and auto-thermal reforming) was conducted to evaluate the potential of reformed fuel. A system layout was proposed for each reforming technique and a detailed thermodynamic analysis using first- and second-law approaches were used to identify the sources of efficiency improvements. The results showed that reformed fuel combustion with a near TDC injection of diesel fuel can increase engine-only efficiency by 4% absolute when compared to a conventional diesel baseline. The efficiency improvements were a result of reduced heat transfer and shorter, more thermodynamically efficient, combustion process. For exothermic reforming processes, losses in the reformer outweigh the improvements to engine efficiency, while for endothermic processes the recovery of exhaust energy was able to allow the system efficiency to retain a large portion of the benefits to the engine combustion. Energy flow analysis showed that the reformer temperature and availability of high grade exhaust heat were the main limiting factors preventing higher efficiencies. RCCI combustion was explored experimentally for its potential to expand on the optimization results and achieve low soot and NOx emissions. The results showed that reformed fuel can be used with diesel to enable RCCI combustion and resulted in low NOx and soot emissions while achieving efficiencies similar to conventional diesel combustion. Experiments showed that the ratio H2/(H2+CO) is an important parameter for optimal engine operation. Under part-load conditions, fractions of H2/(H2+CO) higher than 60% led to pressure oscillations inside the cylinder that substantially increased heat transfer and negated any efficiency benefits. The system analysis approach was applied to the experimental results and showed that chemical equilibrium limited operation of the engine to sub-optimal operating conditions. RCCI combustion was able to achieve "diesel like" system level efficiencies without optimization of either the engine operating conditions or the combustion system. Reformed fuel RCCI was able to provide a pathway to meeting current and future emission targets with a reduction or complete elimination of aftertreatment costs. Particle size distribution experiments showed that addition of reformed fuel had a significant impact on the shape of the particle size distribution. Addition of reformed fuel reduced accumulation-mode particle concentration while increasing nucleation-mode particles. When considering the full range of particle sizes there was a significant increase in total particle concentration. However, when considering currently regulated (Dm>23nm) particles, total concentration was comparable. To address limitations identified in the system analysis of the RCCI experiments a solid oxide fuel cell was combined with the engine into a hybrid electrochemical combustion system. The addition of the fuel cell addresses the limitations by providing sufficient high grade heat to fully drive the reforming reactions. From a system level perspective, the impact of the high frequency oscillations observed in the experiments are reduced, as the system efficiency is less dependent on the engine efficiency. From an engine perspective, the high operating pressures and low reactivity of the anode gas allow reduction of the likelihood of such events. A 0-D system level code was developed and used to find representative conditions for experimental engine validation. The results showed that the system can achieve system electrical efficiencies higher than 70% at 1 MWe power level. Experimental validation showed that the engine was able to operate under both RCCI and HCCI combustion modes and resulted in low emissions and stable combustion. The potential of a hybrid electrochemical combustion system was demonstrated for high efficiency power generation

Download or read book HCCI and CAI Engines for the Automotive Industry written by Hua Zhao and published by CRC Press. This book was released on 2007-09-10 with total page 562 pages. Available in PDF, EPUB and Kindle. Book excerpt: Homogeneous charge compression ignition (HCCI)/controlled auto-ignition (CAI) has emerged as one of the most promising engine technologies with the potential to combine fuel efficiency and improved emissions performance, offering reduced nitrous oxides and particulate matter alongside efficiency comparable with modern diesel engines. Despite the considerable advantages, its operational range is rather limited and controlling the combustion (timing of ignition and rate of energy release) is still an area of on-going research. Commercial applications are, however, close to reality. HCCI a.

Download or read book High Load Reactivity Controlled Compression Ignition RCCI Combustion in a Heavy Duty Engine written by Newell Grant Allen and published by . This book was released on 2014 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Reactivity Controlled Compression Ignition RCCI Combustion written by and published by . This book was released on 2012 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Premixed Compression Ignition (PCI) strategies are promising methods to achieve low engine out NOx and soot emissions and high efficiency. However, PCI strategies have failed to see widespread implementation due to difficulties controlling the heat release rate and lack of an adequate combustion phasing control mechanism. In this research, a dual fuel reactivity controlled compression ignition (RCCI) concept is proposed to address these issues. In the RCCI strategy, two fuels with different auto ignition characteristics are blended inside the combustion chamber. Combustion phasing is controlled by the relative ratios of these two fuels and the combustion duration is controlled by spatial stratification between the two fuels. The study has three primary sections. The first section highlights the development of the RCCI strategy using computational fluid dynamics (CFD) modeling. The second section uses CFD modeling and metal engine experiments to evaluate the performance and emissions characteristics of RCCI combustion. The metal engine experiments confirm that RCCI operation is possible over a wide range of conditions with near zero levels of NOx and soot emissions. Additionally, it is found that RCCI is able to achieve very high indicated efficiency (greater than 50%) by lowering heat transfer losses and improving the control over the combustion phasing and burn duration. The third section uses optical engine experiments to validate model predictions and provide a fundamental explanation for the processes controlling RCCI combustion. The results of the optical engine experiments clarify the mechanisms controlling the RCCI energy release. Chemiluminescence imaging shows that RCCI features a reaction zone that appears to grow by the appearance of small auto ignition pockets. The fuel tracer fluorescence imaging shows that the ignition locations correspond to the regions with the lowest primary reference fuel (PRF) number and highest equivalence ratio. The rate of reaction zone growth is then controlled by the level of stratification in equivalence ratio and PRF number. Kinetics modeling based on the fuel tracer fluorescence imaging shows that the PRF number has the largest effect on the rate of reaction zone growth.

Download or read book Experimental Investigation of Transient RCCI Combustion in a Light Duty Diesel Engine written by and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Low Temperature Combustion (LTC) is currently being researched as a way to reduce problematic emissions (i.e., NOx and PM) from compression-ignition engines while maintaining high fuel efficiency. One of the primary types of LTC is Premixed Compression Ignition (PCI), with some examples of PCI being homogeneous charge compression ignition (HCCI), premixed charge compression ignition (PCCI), reactivity controlled compression ignition (RCCI) and partially premixed combustion (PPC). These LTC strategies use early fuel injections to allow sufficient time for air/fuel mixing before combustion. By increasing the amount of air/fuel premixing, NOx and PM emissions can be lowered due to the reduced local and global equivalence ratios. The lean nature of PCI also maintains high thermal efficiency due to the reduced heat transfer losses from the reduced peak combustion temperatures. However, too much air/fuel premixing can lead to rapid energy release rates, limiting the operation space for PCI. To combat this problem, the combustion strategy of interest for the study, RCCI, uses fuel reactivity gradients to increase combustion duration (i.e., reduce the energy release rate) and phasing control, thereby increasing the engine operating space for PCI operation. Previous tests [1-7] have shown promising results for petroleum-based fuels with RCCI. Recent work at Oak Ridge National Laboratory (ORNL) has shown how blends of biofuels with petroleum fuels can improve RCCI combustion performance [8,9] The work sets out to examine biofuel performance over a wide engine operating space both at steady-state and transient operating conditions with RCCI combustion. It is hoped to demonstrate the capability and effects of using bio-derived fuels in place of conventional petroleum-derived fuels for advanced combustion strategies under real-world operating conditions. In RCCI operation, blends of biodiesel and ethanol fuels will be investigated to examine the fuel effects on the combustion event.

Download or read book Alternative Fuels and Advanced Vehicle Technologies for Improved Environmental Performance written by Richard Folkson and published by Woodhead Publishing. This book was released on 2022-07-27 with total page 800 pages. Available in PDF, EPUB and Kindle. Book excerpt: Alternative Fuels and Advanced Vehicle Technologies for Improved Environmental Performance: Towards Zero Carbon Transportation, Second Edition provides a comprehensive view of key developments in advanced fuels and vehicle technologies to improve the energy efficiency and environmental impact of the automotive sector. Sections consider the role of alternative fuels such as electricity, alcohol and hydrogen fuel cells, as well as advanced additives and oils in environmentally sustainable transport. Other topics explored include methods of revising engine and vehicle design to improve environmental performance and fuel economy and developments in electric and hybrid vehicle technologies. This reference will provide professionals, engineers and researchers of alternative fuels with an understanding of the latest clean technologies which will help them to advance the field. Those working in environmental and mechanical engineering will benefit from the detailed analysis of the technologies covered, as will fuel suppliers and energy producers seeking to improve the efficiency, sustainability and accessibility of their work. Provides a fully updated reference with significant technological advances and developments in the sector Presents analyses on the latest advances in electronic systems for emissions control, autonomous systems, artificial intelligence and legislative requirements Includes a strong focus on updated climate change predictions and consequences, helping the reader work towards ambitious 2050 climate change goals for the automotive industry

Download or read book Experimental Investigation of Fuel Reactivity Controlled Compression Ignition RCCI Combustion Mode in a Multi Cylinder Light Duty Diesel Engine written by and published by . This book was released on 2011 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: An experimental study was performed to provide the combustion and emission characteristics resulting from fuel-reactivity controlled compression ignition (RCCI) combustion mode utilizing dual-fuel approach in a light-duty, multi-cylinder diesel engine. In-cylinder fuel blending using port fuel injection of gasoline before intake valve opening (IVO) and early-cycle, direct injection of diesel fuel was used as the charge preparation and fuel blending strategy. In order to achieve the desired auto-ignition quality through the stratification of the fuel-air equivalence ratio (), blends of commercially available gasoline and diesel fuel were used. Engine experiments were performed at an engine speed of 2300rpm and an engine load of 4.3bar brake mean effective pressure (BMEP). It was found that significant reduction in both nitrogen oxide (NOx) and particulate matter (PM) was realized successfully through the RCCI combustion mode even without applying exhaust gas recirculation (EGR). However, high carbon monoxide (CO) and hydrocarbon (HC) emissions were observed. The low combustion gas temperature during the expansion and exhaust processes seemed to be the dominant source of high CO emissions in the RCCI combustion mode. The high HC emissions during the RCCI combustion mode could be due to the increased combustion quenching layer thickness as well as the -stratification at the periphery of the combustion chamber. The slightly higher brake thermal efficiency (BTE) of the RCCI combustion mode was observed than the other combustion modes, such as the conventional diesel combustion (CDC) mode, and single-fuel, premixed charge compression ignition (PCCI) combustion mode. The parametric study of the RCCI combustion mode revealed that the combustion phasing and/or the peak cylinder pressure rise rate of the RCCI combustion mode could be controlled by several physical parameters premixed ratio (rp), intake swirl intensity, and start of injection (SOI) timing of directly injected fuel unlike other low temperature combustion (LTC) strategies.

Download or read book Characteristics and Control of Low Temperature Combustion Engines written by Rakesh Kumar Maurya and published by Springer. This book was released on 2017-11-03 with total page 553 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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. .

Download or read book Modeling and Control of Maximum Pressure Rise Rate in RCCI Engines written by and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : Low Temperature Combustion (LTC) is a combustion strategy that burns fuel at lower temperatures and leaner mixtures in order to achieve high efficiency and near zero NOx emissions. Since the combustion happens at lower temperatures it inhibits the formation of NOx and soot emissions. One such strategy is Reactivity Controlled Compression Ignition (RCCI). One characteristic of RCCI combustion and LTC com- bustion in general is short burn durations which leads to high Pressure Rise Rates (PRR). This limits the operation of these engines to lower loads as at high loads, the Maximum Pressure Rise Rate (MPRR) hinders the use of this combustion strategy. This thesis focuses on the development of a model based controller that can control the Crank Angle for 50% mass fraction burn (CA50) and Indicated Mean Effective Pressure (IMEP) of an RCCI engine while limiting the MPRR to a pre determined limit. A Control Oriented Model (COM) is developed to predict the MPRR in an RCCI engine. This COM is then validated against experimental data. A statistical analysis of the experimental data is conducted to understand the accuracy of the COM. The results show that the COM is able to predict the MPRR with reasonable accuracy in steady state and transient conditions. Also, the COM is able to capture the trends during transient operation. This COM is then included in an existing cycle by cycle dynamic RCCI engine model and used to develop a Linear Parameter Varying (LPV) representation of an RCCI engine using Data Driven Modeling (DDM) approach with Support Vector Machines (SVM). This LPV representation is then used along with a Model Predictive Controller (MPC) to control the CA50 and IMEP of the RCCI engine model while limiting the MPRR. The controller was able to track the desired CA50 and IMEP with a mean error of 0.9 CAD and 4.7 KPa respectively while maintaining the MPRR below 5.8 bar/CAD.

Download or read book MODEL BASED CONTROL OF AN RCCI ENGINE written by and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract : Reactivity controlled compression ignition (RCCI) is a combustion strategy that offers high fuel conversion efficiency and near zero emissions of NOx and soot which can help in improving fuel economy in mobile and stationary internal combustion engine (ICE) applications and at the same time lower engine-out emissions. One of the main challenges associated with RCCI combustion is the difficulty in simultaneously controlling combustion phasing, engine load, and cyclic variability during transient engine operations. This thesis focuses on developing model based controllers for cycle-to-cycle combustion phasing and load control during transient operations. A control oriented model (COM) is developed by using mean value models to predict start of combustion (SOC) and crank angle of 50% mass fraction burn (CA50). The COM is validated using transient data from an experimental RCCI engine. The validation results show that the COM is able to capture the experimental trends in CA50 and indicated mean effective pressure (IMEP). The COM is then used to develop a linear quadratic integral (LQI) controller and model predictive controllers (MPC). Premixed ratio (PR) and start of injection (SOI) are the control variables used to control CA50, while the total fuel quantity (FQ) is the engine variable used to control load. The selection between PR and SOI is done using a sensitivity based algorithm. Experimental validation results for reference tracking using LQI and MPC show that the desired CA50 and IMEP can be attained in a single cycle during step-up and step-down transients and yield an average error of less than 1.6 crank angle degrees (CAD) in the CA50 and less than 35 kPa in the IMEP. This thesis presents the first study in the literature to design and implement LQI and MPC combustion controllers for RCCI engines.

Download or read book Dual fuel Reactivity Controlled Compression Ignition RCCI with Alternative Fuels written by and published by . This book was released on 2013 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This research will demonstrate that Reactivity Controlled Compression Ignition (RCCI) has several advantages over other LTC concepts in regards to fuel flexibility and combustion controllability. RCCI is a dual-fuel partially premixed combustion concept. In this strategy, a low reactivity fuel, such as gasoline or an alcohol fuel, is premixed via port fuel injection (PFI) and a high reactivity fuel, such as diesel fuel, is direct injected (DI) during the compression stroke. Once it was clear that dual-fuel RCCI operation had great potential in terms of combustion controllability, which is a great challenge for LTC strategies, the study focused on alternative fuels with RCCI combustion. The light-duty engine was used to study two different fuel combinations: gasoline/diesel and methanol/diesel. In addition to the fuels comparison, a modified piston bowl geometry was studied and compared to the stock re-entrant bowl. The modified piston featured a wide/shallow bowl with a matched geometric compression ratio to the stock piston of ~17.3. Using the modified piston, the gross indicated efficiency of RCCI combustion was significantly improved at light loads due to increases in combustion efficiency and decreases in heat transfer losses. At higher loads the modified piston also performed better than the stock piston, but the improvements were not as significant. The final portion of this research looks at the effects of cetane improvers on gasoline, ethanol, and methanol's fuel reactivity and the implications for RCCI combustion. In all three base fuels it was found that 2-ethylhexyl nitrate is more effective at increasing fuel reactivity (i.e., suppressing the octane number) compared to di-tert-butyl peroxide. However, 2-ethylhexyl nitrate has a potential disadvantage due its nitrate group, which can manifest itself as NOx emissions in the exhaust. The relationship between the fuel-bound nitrate group and the engine-out NOx emissions was extensively characterized. It was also observed that methanol's response to cetane improvers was better than that of ethanol, in spite of the fact that they have similar reactivities in their neat form.

Download or read book Natural Gas Engines written by Kalyan Kumar Srinivasan and published by Springer. This book was released on 2018-11-03 with total page 419 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the various advanced reciprocating combustion engine technologies that utilize natural gas and alternative fuels for transportation and power generation applications. It is divided into three major sections consisting of both fundamental and applied technologies to identify (but not limited to) clean, high-efficiency opportunities with natural gas fueling that have been developed through experimental protocols, numerical and high-performance computational simulations, and zero-dimensional, multizone combustion simulations. Particular emphasis is placed on statutes to monitor fine particulate emissions from tailpipe of engines operating on natural gas and alternative fuels.

Download or read book Advanced Engine Diagnostics written by Avinash Kumar Agarwal and published by Springer. This book was released on 2018-11-07 with total page 253 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book describes the discusses advanced fuels and combustion, emission control techniques, after-treatment systems, simulations and fault diagnostics, including discussions on different engine diagnostic techniques such as particle image velocimetry (PIV), phase Doppler interferometry (PDI), laser ignition. This volume bridges the gap between basic concepts and advanced research in internal combustion engine diagnostics, making it a useful reference for both students and researchers whose work focuses on achieving higher fuel efficiency and lowering emissions.

Download or read book Low temperature Combustion and Autoignition written by M.J. Pilling and published by Elsevier. This book was released on 1997-11-27 with total page 823 pages. Available in PDF, EPUB and Kindle. Book excerpt: Combustion has played a central role in the development of our civilization which it maintains today as its predominant source of energy. The aim of this book is to provide an understanding of both fundamental and applied aspects of low-temperature combustion chemistry and autoignition. The topic is rooted in classical observational science and has grown, through an increasing understanding of the linkage of the phenomenology to coupled chemical reactions, to quite profound advances in the chemical kinetics of both complex and elementary reactions. The driving force has been both the intrinsic interest of an old and intriguing phenomenon and the centrality of its applications to our economic prosperity. The volume provides a coherent view of the subject while, at the same time, each chapter is self-contained.