Characterization Of Engine Control Authority On Hcci Combustion As The High Load Limit Is Approached

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Characterization of Engine Control Authority on HCCI Combustion as the High Load Limit is Approached

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ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (16 download)

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Book Synopsis Characterization of Engine Control Authority on HCCI Combustion as the High Load Limit is Approached by :

Download or read book Characterization of Engine Control Authority on HCCI Combustion as the High Load Limit is Approached written by and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: While the potential emissions and efficiency benefits of homogeneous charge compression ignition (HCCI) combustion are well known, realizing the potentials on a production intent engine presents numerous challenges. In this study we focus on characterizing the authority of the available engine controls as the high load limit of HCCI combustion is approached. The experimental work is performed on a boosted single-cylinder research engine equipped with direct injection (DI) fueling, cooled external exhaust gas recirculation (EGR), and a hydraulic valve actuation (HVA) valve train to enable the negative valve overlap (NVO) breathing strategy. Valve lift and duration are held constant while phasing is varied in an effort to make the results as relevant as possible to production intent cam-based variable valve actuation (VVA) systems on multi-cylinder engines. Results presented include engine loads from 350 to 650 kPa IMEPnet and manifold pressure from 98 to 190 kPaa at 2000 rpm. It is found that in order to increase engine load to 650 kPa IMEPnet, it is necessary to increase manifold pressure and external EGR while reducing the NVO duration. Both NVO duration and fuel injection timing are effective means of controlling combustion phasing, with NVO duration being a coarse control and fuel injection timing being a fine control. NOX emissions are low throughout the study, with emissions below 0.1 g/kW-h at all boosted HCCI conditions, while good combustion efficiency is maintained (>96.5%). Net indicated thermal efficiency increases with load up to 600 kPa IMEPnet, where a peak efficiency of 41% is achieved. Results of independent parametric investigations are presented on the effect of external EGR, intake effect of manifold pressure, and the effect of NVO duration. It is found that increasing EGR at a constant manifold pressure and increasing manifold pressure at a constant EGR rate both have the effect of retarding combustion phasing. It is also found that combustion phasing becomes increasingly sensitive to NVO duration as engine load increases. Finally, comparisons are made between three commonly used noise metrics (AVL noise meter, ringing intensity (RI), and maximum pressure rise rate (MPRR)). It is found that compared to the AVL noise meter, RI significantly underestimates combustion noise under boosted conditions.

An Experimental Characterization of HCCI/DI Mixed-mode Operation Utilizing External Mixture Formation in a 2.5 Liter Common Rail Diesel Engine

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Author : Joel Michael Cowgill
Publisher :
ISBN 13 :
Total Pages : 338 pages
Book Rating : 4.:/5 (212 download)

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Book Synopsis An Experimental Characterization of HCCI/DI Mixed-mode Operation Utilizing External Mixture Formation in a 2.5 Liter Common Rail Diesel Engine by : Joel Michael Cowgill

Download or read book An Experimental Characterization of HCCI/DI Mixed-mode Operation Utilizing External Mixture Formation in a 2.5 Liter Common Rail Diesel Engine written by Joel Michael Cowgill and published by . This book was released on 2007 with total page 338 pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In order to meet future emissions requirements for internal combustion engines, continuing advances in emission reduction techniques are imperative. A method for in-cylinder emissions reduction currently being investigated quite extensively is Homogeneous Charge Compression Ignition (HCCI). An engine operating in pure HCCI combustion is capable of reducing NOx and PM emissions to near zero levels. However, HCCI engines are typically limited to low and mid-load operation due to high cylinder pressure-rise-rates associated with compression ignition of a homogeneous charge. One method of extending this operating range, investigated in this work, is the combination of HCCI combustion with standard CIDI combustion in a mixed-mode operating scheme. This method combines the emissions benefits of HCCI combustion with the high efficiency operation of standard Diesel combustion. Steady-state engine operating conditions are explored in pure HCCI and HCCI/DI mixed-mode operation and compared to baseline operating conditions of standard CIDI in a production 2.5L common rail Diesel engine. In this work, homogeneous mixture preparation is performed utilizing an external atomization device. In preliminary characterization, the effects of HCCI ratio, EGR ratio and DI timing are explored and the advantages of mixed-mode operation is verified over that of standard CIDI Diesel combustion. Following definition of the most important combustion control parameters, a comprehensive sensitivity analysis of EGR ratio, DI timing, engine speed and engine load is also conducted in mixed-mode operation with a focus on the effects of engine out emissions and combustion characteristics. Additionally, the limits of HCCI operation in this particular engine are also explored in order to define a baseline location for the transition to mixed-mode operation. In order to truly ascertain the benefits of mixed-mode combustion, results of mixed-mode operation are contrasted against manufacturer's engine maps for NOx and PM emissions as well as fuel consumption. The results of rough optimization illustrate that significant reduction in NOx emissions are possible with reasonable PM emissions easily eliminated with a current generation DPF. Fuel consumption is also found to be significantly reduced in most mixed-mode cases where up to 15 percent reductions are possible in the operating range considered. This fuel consumption decrease is also found to extend to pure HCCI operation and close to 10 percent reductions are discovered between operating speeds of 1500 and 2500 RPM at slightly more than 2 bar BMEP engine load. To set the stage for further research, basic transient operation is also investigated. With a firm grasp and understanding of steady-state operating conditions, control of the transition between pure HCCI, mixed-mode and pure CIDI combustion schemes can be explored. The basic structure of this control format includes pure HCCI operation at low-loads, mixed-mode operation in mid-loads and standard CIDI operation at high-loads. In this work, HCCI operation is found to be relatively insensitive to engine speed; however, increases in engine speed may affect the load threshold conditions at which these transitions occur.

Advanced Combustion for Sustainable Transport

Author : Avinash Kumar Agarwal
Publisher : Springer Nature
ISBN 13 : 9811684189
Total Pages : 367 pages
Book Rating : 4.8/5 (116 download)

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Book Synopsis Advanced Combustion for Sustainable Transport by : Avinash Kumar Agarwal

Download or read book Advanced Combustion for Sustainable Transport written by Avinash Kumar Agarwal and published by Springer Nature. This book was released on 2021-12-12 with total page 367 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is based on advanced combustion technologies currently employed in internal combustion engines. It discusses different strategies for improving conventional diesel combustion. The volume includes chapters on low-temperature combustion techniques of compression-ignition engines which results in significant reduction of NOx and soot emissions. The content also highlights newly evolved gasoline compression technology and optical techniques in advanced gasoline direct injection engines. the research and its outcomes presented here highlight advancements in combustion technologies, analysing various issues related to in-cylinder combustion, pollutant formation and alternative fuels. This book will be of interest to those in academia and industry involved in fuels, IC engines, engine combustion research.

Examination of the High Load Limit of an HCCI Engine

Author : Nathan Charles Anderson
Publisher :
ISBN 13 :
Total Pages : 72 pages
Book Rating : 4.:/5 (247 download)

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Book Synopsis Examination of the High Load Limit of an HCCI Engine by : Nathan Charles Anderson

Download or read book Examination of the High Load Limit of an HCCI Engine written by Nathan Charles Anderson and published by . This book was released on 2008 with total page 72 pages. Available in PDF, EPUB and Kindle. Book excerpt: The implementation of homogenous charge compression ignition (HCCI) to gasoline engines is constrained by many factors. This work examines constrains imposed by nitric oxide (NOx) emission and by the need to maintain a minimum catalyst temperature on HCCI operation. Then the nature of the approach to high load limit was examined for three fuels with very different behavior. An engine simulation was used to examine constrains imposed by NOx emission and by catalyst temperature requirement. The valve timing in a HCCI engine using NegativeValve-Overlap (NVO) was varied in the simulation to control the operating point. The engine speed and intake pressure (turbocharged mode) were varied. The High Load Limit (HLL) was attained when the NOx emission reached the regulated level for a Partial-Zero-Emissions-Vehicle (PZEV). This occurred when the engine was running at the lowest speed and the highest intake pressure. Unreasonably large residual fraction was required to achieve the NOx limit unless a three-way catalyst is used. The engine behavior in the operating trajectory to the HLL was examined by using two Primary Reference fuels (PRF60 and PRF90) and a fuel blended from refinery feed stock. The latter fuel had Extremely Low Aromatic and Olefin content and is referred to as the ELAO fuel. For PRF60 (the knock prone fuel), the Maximum Pressure Rise Rate (MPRR) increased with increase in load (by reduction of residual). The HLL was attained when the MPRR reached a pre-determined level of 5MPa/ms. For PRF90 (the knock resistant fuel), however, the MPRR decreased with increase in load, and the HLL was constrained by ignition failure. For the ELAO fuel, the MPRR first increased and then decreased with increase in load. The HLL was thus constrained by ignition failure. Thus depending on the fuel properties, there could be very different engine behaviors in the approach to the HLL of HCCI operation.

Cost, Effectiveness, and Deployment of Fuel Economy Technologies for Light-Duty Vehicles

Author : National Research Council
Publisher : National Academies Press
ISBN 13 : 0309373913
Total Pages : 812 pages
Book Rating : 4.3/5 (93 download)

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Book Synopsis Cost, Effectiveness, and Deployment of Fuel Economy Technologies for Light-Duty Vehicles by : National Research Council

Download or read book Cost, Effectiveness, and Deployment of Fuel Economy Technologies for Light-Duty Vehicles written by National Research Council and published by National Academies Press. This book was released on 2015-09-28 with total page 812 pages. Available in PDF, EPUB and Kindle. Book excerpt: The light-duty vehicle fleet is expected to undergo substantial technological changes over the next several decades. New powertrain designs, alternative fuels, advanced materials and significant changes to the vehicle body are being driven by increasingly stringent fuel economy and greenhouse gas emission standards. By the end of the next decade, cars and light-duty trucks will be more fuel efficient, weigh less, emit less air pollutants, have more safety features, and will be more expensive to purchase relative to current vehicles. Though the gasoline-powered spark ignition engine will continue to be the dominant powertrain configuration even through 2030, such vehicles will be equipped with advanced technologies, materials, electronics and controls, and aerodynamics. And by 2030, the deployment of alternative methods to propel and fuel vehicles and alternative modes of transportation, including autonomous vehicles, will be well underway. What are these new technologies - how will they work, and will some technologies be more effective than others? Written to inform The United States Department of Transportation's National Highway Traffic Safety Administration (NHTSA) and Environmental Protection Agency (EPA) Corporate Average Fuel Economy (CAFE) and greenhouse gas (GHG) emission standards, this new report from the National Research Council is a technical evaluation of costs, benefits, and implementation issues of fuel reduction technologies for next-generation light-duty vehicles. Cost, Effectiveness, and Deployment of Fuel Economy Technologies for Light-Duty Vehicles estimates the cost, potential efficiency improvements, and barriers to commercial deployment of technologies that might be employed from 2020 to 2030. This report describes these promising technologies and makes recommendations for their inclusion on the list of technologies applicable for the 2017-2025 CAFE standards.

Characteristics and Control of Low Temperature Combustion Engines

Author : Rakesh Kumar Maurya
Publisher : Springer
ISBN 13 : 3319685082
Total Pages : 553 pages
Book Rating : 4.3/5 (196 download)

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Book Synopsis Characteristics and Control of Low Temperature Combustion Engines by : Rakesh Kumar Maurya

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. .

Maximizing Power Output in Homogeneous Charge Compression Ignition (HCCI) Engines and Enabling Effective Control of Combustion Timing

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Author : Samveg Saxena
Publisher :
ISBN 13 :
Total Pages : 238 pages
Book Rating : 4.:/5 (785 download)

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Book Synopsis Maximizing Power Output in Homogeneous Charge Compression Ignition (HCCI) Engines and Enabling Effective Control of Combustion Timing by : Samveg Saxena

Download or read book Maximizing Power Output in Homogeneous Charge Compression Ignition (HCCI) Engines and Enabling Effective Control of Combustion Timing written by Samveg Saxena and published by . This book was released on 2011 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt: Homogeneous Charge Compression Ignition (HCCI) engines are one of the most promising engine technologies for the future of energy conversion from clean, efficient combustion. HCCI engines allow high efficiency and lower CO2 emission through the use of high compression ratios and the removal of intake throttle valves (like Diesel), and allow very low levels of urban pollutants like nitric oxide and soot (like Otto). These engines, however, are not without their challenges, such as low power density compared with other engine technologies, and a difficulty in controlling combustion timing. This dissertation first addresses the power output limits. The particular strategies for enabling high power output investigated in this dissertation focus on avoiding five critical limits that either damage an engine, drastically reduce efficiency, or drastically increase emissions: 1) ringing limits, 2) peak in-cylinder pressure limits, 3) misfire limits, 4) low intake temperature limits, and 5) excessive emissions limits. The research shows that the key factors that enable high power output, sufficient for passenger vehicles, while simultaneously avoiding the five limits defined above are the use of: 1) high intake air pressures allowing improved power output, 2) highly delayed combustion timing to avoid ringing limits, and 3) using the highest possible equivalence ratio before encountering ringing limits. These results are revealed by conducting extensive experiments spanning a wide range of operating conditions on a multi-cylinder HCCI engine. Second, this dissertation discusses strategies for effectively sensing combustion characteristics on a HCCI engine. For effective feedback control of HCCI combustion timing, a sensor is required to quantify when combustion occurs. Many laboratory engines use in-cylinder pressure sensors but these sensors are currently prohibitively expensive for wide-scale commercialization. Instead, ion sensors made from inexpensive sparkplugs are proposed for sensing combustion timing. Ion sensing, however, is unreliable under certain HCCI conditions. The dissertation presents two strategies for improving the usefulness of ion sensors in HCCI engines: 1) the use of tiny fractions of metal-acetate fuel additives that expand the useful range of ion sensors, and 2) the use of ion sensors for detecting excessive ringing that must be avoided in HCCI engines. These two innovative research efforts make ion sensors viable for sensing combustion characteristics across the full range of HCCI operation, making them effective for use in engine control systems. In summary, this Ph. D dissertation addresses two important technical challenges facing HCCI engines: power output limits, and difficulty in sensing combustion characteristics for control applications. The strategies proposed in this dissertation research bring HCCI engines closer to widespread commercialization allowing vehicles to operate with significantly higher efficiency and with cleaner emissions.

DI-HCCI Engine Control System Development

Author : Kushal Narayanaswamy
Publisher :
ISBN 13 :
Total Pages : 226 pages
Book Rating : 4.:/5 (89 download)

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Book Synopsis DI-HCCI Engine Control System Development by : Kushal Narayanaswamy

Download or read book DI-HCCI Engine Control System Development written by Kushal Narayanaswamy and published by . This book was released on 2006 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt:

HCCI Combustion

Author :
Publisher :
ISBN 13 :
Total Pages : 5 pages
Book Rating : 4.:/5 (684 download)

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Book Synopsis HCCI Combustion by :

Download or read book HCCI Combustion written by and published by . This book was released on 2001 with total page 5 pages. Available in PDF, EPUB and Kindle. Book excerpt: Homogeneous charge compression ignition (HCCI) is a new combustion technology that may develop as an alternative to diesel engines with high efficiency and low NOx and particulate matter emissions. This paper describes the HCCI research activities being currently pursued at Lawrence Livermore National Laboratory and at the University of California Berkeley. Current activities include analysis as well as experimental work. On analysis, we have developed two powerful tools: a single zone model and a multi-zone model. The single zone model has proven very successful in predicting start of combustion and providing reasonable estimates for peak cylinder pressure, indicated efficiency and NOX emissions. This model is being applied to develop detailed engine performance maps and control strategies, and to analyze the problem of engine startability. The multi-zone model is capable of very accurate predictions of the combustion process, including HC and CO emissions. The multi-zone model h as applicability to the optimization of combustion chamber geometry and operating conditions to achieve controlled combustion at high efficiency and low emissions. On experimental work, we have done a thorough evaluation of operating conditions in a 4-cylinder Volkswagen TDI engine. The engine has been operated over a wide range of conditions by adjusting the intake temperature and the fuel flow rate. Satisfactory operation has been obtained over a wide range of operating conditions. Cylinder-to-cylinder variations play an important role in limiting maximum power, and should be controlled to achieve satisfactory performance.

Hcci and Cai Engines for the Automotive Industry

Author : H Zhao
Publisher : Elsevier
ISBN 13 : 184569354X
Total Pages : 557 pages
Book Rating : 4.8/5 (456 download)

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Book Synopsis Hcci and Cai Engines for the Automotive Industry by : H Zhao

Download or read book Hcci and Cai Engines for the Automotive Industry written by H Zhao and published by Elsevier. This book was released on 2007-08-02 with total page 557 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 and CAI engines for the automotive industry presents the state-of-the-art in research and development on an international basis, as a one-stop reference work. The background to the development of HCCI / CAI engine technology is described. Basic principles, the technologies and their potential applications, strengths and weaknesses, as well as likely future trends and sources of further information are reviewed in the areas of gasoline HCCI / CAI engines; diesel HCCI engines; HCCI / CAI engines with alternative fuels; and advanced modelling and experimental techniques. The book provides an invaluable source of information for scientific researchers, R&D engineers and managers in the automotive engineering industry worldwide. Presents the state-of-the-art in research and development on an international basis An invaluable source of information for scientific researchers, R&D engineers and managers in the automotive engineering industry worldwide Looks at one of the most promising engine technologies around

High Efficiency, Low Emissions Homogeneous Charge Compression Ignition (HCCI) Engines

Author :
Publisher :
ISBN 13 :
Total Pages : 103 pages
Book Rating : 4.:/5 (962 download)

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Book Synopsis High Efficiency, Low Emissions Homogeneous Charge Compression Ignition (HCCI) Engines by :

Download or read book High Efficiency, Low Emissions Homogeneous Charge Compression Ignition (HCCI) Engines written by and published by . This book was released on 2010 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: This is the final report of the High Efficiency Clean Combustion (HECC) Research Program for the U.S. Department of Energy. Work under this co-funded program began in August 2005 and finished in July 2010. The objective of this program was to develop and demonstrate a low emission, high thermal efficiency engine system that met 2010 EPA heavy-duty on-highway truck emissions requirements (0.2g/bhp-hr NOx, 0.14g/bhp-hr HC and 0.01g/bhp-hr PM) with a thermal efficiency of 46%. To achieve this goal, development of diesel homogenous charge compression ignition (HCCI) combustion was the chosen approach. This report summarizes the development of diesel HCCI combustion and associated enabling technologies that occurred during the HECC program between August 2005 and July 2010. This program showed that although diesel HCCI with conventional US diesel fuel was not a feasible means to achieve the program objectives, the HCCI load range could be increased with a higher volatility, lower cetane number fuel, such as gasoline, if the combustion rate could be moderated to avoid excessive cylinder pressure rise rates. Given the potential efficiency and emissions benefits, continued research of combustion with low cetane number fuels and the effects of fuel distillation are recommended. The operation of diesel HCCI was only feasible at part-load due to a limited fuel injection window. A 4% fuel consumption benefit versus conventional, low-temperature combustion was realized over the achievable operating range. Several enabling technologies were developed under this program that also benefited non-HCCI combustion. The development of a 300MPa fuel injector enabled the development of extended lifted flame combustion. A design methodology for minimizing the heat transfer to jacket water, known as precision cooling, will benefit conventional combustion engines, as well as HCCI engines. An advanced combustion control system based on cylinder pressure measurements was developed. A Well-to-wheels analysis of the energy flows in a mobile vehicle system and a 2nd Law thermodynamic analysis of the engine system were also completed under this program.

Control and Robustness Analysis of Homogeneous Charge Compression Ignition Using Exhaust Recompression

Author : Hsien-Hsin Liao
Publisher : Stanford University
ISBN 13 :
Total Pages : 201 pages
Book Rating : 4.F/5 ( download)

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Book Synopsis Control and Robustness Analysis of Homogeneous Charge Compression Ignition Using Exhaust Recompression by : Hsien-Hsin Liao

Download or read book Control and Robustness Analysis of Homogeneous Charge Compression Ignition Using Exhaust Recompression written by Hsien-Hsin Liao and published by Stanford University. This book was released on 2011 with total page 201 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been an enormous global research effort to alleviate the current and projected environmental consequences incurred by internal combustion (IC) engines, the dominant propulsion systems in ground vehicles. Two technologies have the potential to improve the efficiency and emissions of IC engines in the near future: variable valve actuation (VVA) and homogeneous charge compression ignition (HCCI). IC engines equipped with VVA systems are proven to show better performance by adjusting the valve lift and timing appropriately. An electro-hydraulic valve system (EHVS) is a type of VVA system that possesses full flexibility, i.e., the ability to change the valve lift and timing independently and continuously, making it an ideal rapid prototyping tool in a research environment. Unfortunately, an EHVS typically shows a significant response time delay that limits the achievable closed-loop bandwidth and, as a result, shows poor tracking performance. In this thesis, a control framework that includes system identification, feedback control design, and repetitive control design is presented. The combined control law shows excellent performance with a root-mean-square tracking error below 40 [Mu]m over a maximum valve lift of 4 mm. A stability analysis is also provided to show that the mean tracking error converges to zero asymptotically with the combined control law. HCCI, the other technology presented in this thesis, is a combustion strategy initiated by compressing a homogeneous air-fuel mixture to auto-ignition, therefore, ignition occurs at multiple points inside the cylinder without noticeable flame propagation. The result is rapid combustion with low peak in-cylinder temperature, which gives HCCI improved efficiency and reduces NOx formation. To initiate HCCI with a typical compression ratio, the sensible energy of the mixture needs to be high compared to a spark ignited (SI) strategy. One approach to achieve this, called recompression HCCI, is by closing the exhaust valve early to trap a portion of the exhaust gas in the cylinder. Unlike a SI or Diesel strategy, HCCI lacks an explicit combustion trigger, as autoignition is governed by chemical kinetics. Therefore, the thermo-chemical conditions of the air-fuel mixture need to be carefully controlled for HCCI to occur at the desired timing. Compounding this challenge in recompression HCCI is the re-utilization of the exhaust gas which creates cycle-to-cycle coupling. Furthermore, the coupling characteristics can change drastically around different operating points, making combustion timing control difficult across a wide range of conditions. In this thesis, a graphical analysis examines the in-cylinder temperature dynamics of recompression HCCI and reveals three qualitative types of temperature dynamics. With this insight, a switching linear model is formulated by combining three linear models: one for each of the three types of temperature dynamics. A switching controller that is composed of three local linear feedback controllers can then be designed based on the switching model. This switching model/control formulation is tested on an experimental HCCI testbed and shows good performance in controlling the combustion timing across a wide range. A semi-definite program is formulated to find a Lyapunov function for the switching model/control framework and shows that it is stable. As HCCI is dictated by the in-cylinder thermo-chemical conditions, there are further concerns about the robustness of HCCI, i.e., the boundedness of the thermo-chemical conditions with uncertainty existing in the ambient conditions and in the engine's own characteristics due to aging. To assess HCCI's robustness, this thesis presents a linear parameter varying (LPV) model that captures the dynamics of recompression HCCI and possesses an elegant model structure that is more amenable to analysis. Based on this model, a recursive algorithm using convex optimization is formulated to generate analytical statements about the boundedness of the in-cylinder thermo-chemical conditions. The bounds generated by the algorithm are also shown to relate well to the data from the experimental testbed.

Dollnstein

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (163 download)

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Book Synopsis Dollnstein by :

Download or read book Dollnstein written by and published by . This book was released on 1974 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

HCCl Combustion

Author :
Publisher :
ISBN 13 :
Total Pages : 10 pages
Book Rating : 4.:/5 (682 download)

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Book Synopsis HCCl Combustion by :

Download or read book HCCl Combustion written by and published by . This book was released on 2001 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt: Homogeneous charge compression ignition (HCCI) is a new combustion technology that may develop as an alternative to diesel engines with high efficiency and low NOx and particulate matter emissions. This paper describes the HCCI research activities being currently pursued at Lawrence Livermore National Laboratory and at the University of California Berkeley. Current activities include analysis as well as experimental work. On analysis, we have developed two powerful tools: a single zone model and a multi-zone model. The single zone model has proven very successful in predicting start of combustion and providing reasonable estimates for peak cylinder pressure, indicated efficiency and NOX emissions. This model is being applied to develop detailed engine performance maps and control strategies, and to analyze the problem of engine startability. The multi-zone model is capable of very accurate predictions of the combustion process, including HC and CO emissions. The multi-zone model has applicability to the optimization of combustion chamber geometry and operating conditions to achieve controlled combustion at high efficiency and low emissions. On experimental work, we have done a thorough evaluation of operating conditions in a 4-cylinder Volkswagen TDI engine. The engine has been operated over a wide range of conditions by adjusting the intake temperature and the fuel flow rate. Satisfactory operation has been obtained over a wide range of operating conditions. Cylinder-to-cylinder variations play an important role in limiting maximum power, and should be controlled to achieve satisfactory performance.

Control Strategies for HCCI Mixed-Mode Combustion

Author :
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (727 download)

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Book Synopsis Control Strategies for HCCI Mixed-Mode Combustion by :

Download or read book Control Strategies for HCCI Mixed-Mode Combustion written by and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Delphi Automotive Systems and ORNL established this CRADA to expand the operational range of Homogenous Charge Compression Ignition (HCCI) mixed-mode combustion for gasoline en-gines. ORNL has extensive experience in the analysis, interpretation, and control of dynamic engine phenomena, and Delphi has extensive knowledge and experience in powertrain compo-nents and subsystems. The partnership of these knowledge bases was important to address criti-cal barriers associated with the realistic implementation of HCCI and enabling clean, efficient operation for the next generation of transportation engines. The foundation of this CRADA was established through the analysis of spark-assisted HCCI data from a single-cylinder research engine. This data was used to (1) establish a conceptual kinetic model to better understand and predict the development of combustion instabilities, (2) develop a low-order model framework suitable for real-time controls, and (3) provide guidance in the initial definition of engine valve strategies for achieving HCCI operation. The next phase focused on the development of a new combustion metric for real-time characterization of the combustion process. Rapid feedback on the state of the combustion process is critical to high-speed decision making for predictive control. Simultaneous to the modeling/analysis studies, Delphi was focused on the development of engine hardware and the engine management system. This included custom Delphi hardware and control systems allowing for flexible control of the valvetrain sys-tem to enable HCCI operation. The final phase of this CRADA included the demonstration of conventional and spark assisted HCCI on the multi-cylinder engine as well as the characterization of combustion instabilities, which govern the operational boundaries of this mode of combustion. ORNL and Delphi maintained strong collaboration throughout this project. Meetings were held on a bi-weekly basis with additional reports, presentation, and meetings as necessary to maintain progress. Delphi provided substantial support through modeling, hardware, data exchange, and technical consultation. This CRADA was also successful at establishing important next steps to further expanding the use of an HCCI engine for improved fuel efficiency and emissions. These topics will be address in a follow-on CRADA. The objectives are: (1) Improve fundamental understanding of the development of combustion instabilities with HCCI operation through modeling and experiments; (2) Develop low-order model and feedback combustion metrics which are well suited to real-time predictive controls; and (3) Construct multi-cylinder engine system with advanced Delphi technologies and charac-terize HCCI behavior to better understand limitations and opportunities for expanded high-efficiency operation.

Gasoline Engine HCCI Combustion

Author : Daniel Dahl
Publisher :
ISBN 13 : 9789173856867
Total Pages : 183 pages
Book Rating : 4.8/5 (568 download)

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Book Synopsis Gasoline Engine HCCI Combustion by : Daniel Dahl

Download or read book Gasoline Engine HCCI Combustion written by Daniel Dahl and published by . This book was released on 2012 with total page 183 pages. Available in PDF, EPUB and Kindle. Book excerpt:

The Role of Fuel in Determining the High Load Limit of Controlled Auto-ignition Engines

Author : Amir Gamal Maria
Publisher :
ISBN 13 :
Total Pages : 99 pages
Book Rating : 4.:/5 (426 download)

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Book Synopsis The Role of Fuel in Determining the High Load Limit of Controlled Auto-ignition Engines by : Amir Gamal Maria

Download or read book The Role of Fuel in Determining the High Load Limit of Controlled Auto-ignition Engines written by Amir Gamal Maria and published by . This book was released on 2009 with total page 99 pages. Available in PDF, EPUB and Kindle. Book excerpt: Controlled Auto-Ignition (CAI) engines have the potential to increase fuel economy while lowering nitrogen oxide and soot emissions. One hurdle that is currently being faced is the engine's inability to operate at high loads due to a large Maximum Pressure Rise Rate (MPRR). To address this issue, this research has been focused on analytically determining the optimum fuel that can be used in a CAI engine to reduce the MPRR and extend the high load limit. The strategy is to use the fuel ignition characteristics to maximize the impact of stratification on reducing the MPRR with sequential ignitions. To quantify the impact of the selected fuel on the high load limit, the fuel's ignition delay curve under constant volume conditions, as a function of the initial concentration and temperature was used. A parametric model of the fuel chemistry was created so that different functional dependences of the ignition delay curve could be produced through adjustment of the model parameters. Then, the ignition delay curve was parameterized, and various artificial fuels were created. The artificial fuels were then tested in an engine simulation under different operating conditions and temperature distributions. The results from the engine simulations provide insight into the characteristics of the optimum fuel ignition delay time versus temperature relationship. As expected, the conclusions depend on the initial boundary conditions applied; particularly the initial cylinder temperature distribution. With a constant temperature applied to the entire charge, the MPRR is reduced when ignition occurs in the Negative Temperature Coefficient (NTC) region. When ignition occurs in the NTC region, the radical concentration in the later stages of the combustion process is reduced, which reduces the MPRR. When an initial quadratic temperature distribution is applied, different regions of the combustion chamber can ignite at different periods, hence reducing the MPRR. However, ignition in the NTC region negates this positive effect, and should therefore be avoided. The functional dependency of the ignition delay time versus initial temperature for the optimum fuel must therefore be created based on the expected initial charge temperature distribution.