Experimental Investigation Of Transient Rcci Combustion In A Light Duty Diesel Engine
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Experimental Investigation Of Transient Rcci Combustion In A Light Duty Diesel Engine
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Author :
language : en
Publisher:
Release Date : 2013
Experimental Investigation Of Transient Rcci Combustion In A Light Duty Diesel Engine written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
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.
Experimental Investigation Of Transient Operation And Low Temperature Combustion In A Light Duty Diesel Engine
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Author :
language : en
Publisher:
Release Date : 2012
Experimental Investigation Of Transient Operation And Low Temperature Combustion In A Light Duty Diesel Engine written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2012 with categories.
Detailed and highly time resolved experimental measurements were used to characterize the effects of transient operation on the performance of a light duty diesel engine, and to identify the physical processes responsible for transient-specific combustion behavior. The engine response to transient events varied with the size and type of transition and the combustion strategy used, but the underlying processes were similar in all cases. Differences in the response rate of the fuel and air systems caused large variations in the equivalence ratio of the combustion charge during transient events. For moderate to low load conditions, this was primarily due to the discrepancy between the instantaneous intake air flow rate and the composition of the intake charge caused by storage of exhaust gas in the EGR system. This effect was particularly significant for early injection LTC operation due to higher EGR rates and greater dependence of combustion phasing on intake charge composition. Individual combustion cycles during transient events were compared to steady state operation at the same speed and load to quantify the differences in physical conditions. The greatest effect on combustion and emissions was due to differences in intake charge composition, which varied significantly between transient and steady state operation. The response time of the common rail pressure also contributed to transient behavior in situations where the target pressure varied with changes in speed or load. During larger load transitions, thermal inertia of the engine system had a significant effect on emissions, particularly UHC, but did not influence the combustion phasing or heat release rate. The characteristic rates of change of the charge gas, fluid, and physical component temperatures in response to speed or load transitions were much slower than those of other variables such as pressures or flow rates, and were consistent with concurrent variations in engine-out emissions levels. Numerous mechanisms by which thermal inertia could affect emissions formation were identified, including variation of the intake manifold charge gas temperature, in-cylinder heat transfer, and changing physical properties of the fuel.
Experimental Investigation Of Fuel Reactivity Controlled Compression Ignition Rcci Combustion Mode In A Multi Cylinder Light Duty Diesel Engine
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Author :
language : en
Publisher:
Release Date : 2011
Experimental Investigation Of Fuel Reactivity Controlled Compression Ignition Rcci Combustion Mode In A Multi Cylinder Light Duty Diesel Engine written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2011 with categories.
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.
Combustion For Power Generation And Transportation
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Author : Avinash Kumar Agarwal
language : en
Publisher: Springer
Release Date : 2017-01-20
Combustion For Power Generation And Transportation written by Avinash Kumar Agarwal and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-01-20 with Technology & Engineering categories.
This research monograph presents both fundamental science and applied innovations on several key and emerging technologies involving fossil and alternate fuel utilization in power and transport sectors from renowned experts in the field. Some of the topics covered include: autoignition in laminar and turbulent nonpremixed flames; Langevin simulation of turbulent combustion; lean blowout (LBO) prediction through symbolic time series analysis; lasers and optical diagnostics for next generation IC engine development; exergy destruction study on small DI diesel engine; and gasoline direct injection. The book includes a chapter on carbon sequestration and optimization of enhanced oil and gas recovery. The contents of this book will be useful to researchers and professionals working on all aspects on combustion.
Characteristics And Control Of Low Temperature Combustion Engines
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Author : Rakesh Kumar Maurya
language : en
Publisher: Springer
Release Date : 2017-11-03
Characteristics And Control Of Low Temperature Combustion Engines written by Rakesh Kumar Maurya and has been published by Springer this book supported file pdf, txt, epub, kindle and other format this book has been release on 2017-11-03 with Technology & Engineering categories.
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. .
Investigation Of Rcci Operation With Customized Pistons In A Light Duty Multi Cylinder Engine Using Dieseline
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Author :
language : en
Publisher:
Release Date : 2016
Investigation Of Rcci Operation With Customized Pistons In A Light Duty Multi Cylinder Engine Using Dieseline written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
In an attempt to increase efficiency and lower critical and highly regulated emissions (i.e., NOx, PM and CO2) many advanced combustion strategies have been investigated. Most of the current strategies fall into the category of low temperature combustion (LTC), which allow emissions mandates to be met in-cylinder along with anticipated reduction in cost and complexity. These strategies, such as homogeneous charge compression ignition (HCCI), premixed charge compression ignition (PCCI), partially premixed combustion (PPC) and reactivity controlled compression ignition (RCCI), use early injection timings, resulting in a highly lean charge with increased specific heat ratios to improve thermal efficiency and reduce PM emissions. Lower combustion temperatures also avoid the activation of NOx formation reactions. However, the lean air/fuel ratio decreases fuel oxidation rates of CO and HC and, due to longer ignition delays with high peak pressure rise rate (PPRR) and heat release rates (HRR), confines the engine’s operating loads and speeds. A strategy to reduce these negative effects of LTC is RCCI, which generally uses two fuels with different reactivities in order to optimize ignitability and equivalence ratio stratification. It has demonstrated improvements in efficiency and low NOx and PM emissions by utilizing in-cylinder fuel blending, while the simultaneous optimization of fuel reactivity results in increased engine operating space. The current work investigates Reactivity Controlled Compression Ignition (RCCI) combustion in a light-duty multi-cylinder engine over steady-state and transient operating conditions using also fast exhaust sampling emissions equipment for UHC, NO and PM measurements. A “single-fuel ” approach for RCCI combustion was studied using port-injected and direct-injected (DI) cetane improved gasoline with custom designed, 15.3:1 compression ratio, pistons. In addition, experiments were conducted using mixtures of gasoline and diesel, i.e., “dieseline”, as the high reactivity fuel. The experiments were performed over a broad selection of “ad hoc” load and speed points in order to examine performance and emission effects of a less reactive DI fuel mixture to in turn reduce the need for a second fuel. This work also helps to demonstrate the requirements for high levels of boost in a multi-cylinder engine during RCCI operation. Comparisons were also made to an HCCI/GCI like combustion strategy using similar gasoline/diesel fuel blends.
Experimental Investigation Of Gasoline Compression Ignition Combustion In A Light Duty Diesel Engine
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Author :
language : en
Publisher:
Release Date : 2013
Experimental Investigation Of Gasoline Compression Ignition Combustion In A Light Duty Diesel Engine written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
Due to increased ignition delay and volatility, low temperature combustion (LTC) research utilizing gasoline fuel has experienced recent interest [1-3]. These characteristics improve air-fuel mixing prior to ignition allowing for reduced emissions of nitrogen oxides (NOx) and soot (or particulate matter, PM). Computational fluid dynamics (CFD) results at the University of Wisconsin-Madison's Engine Research Center (Ra et al. [4, 5]) have validated these attributes and established baseline operating parameters for a gasoline compression ignition (GCI) concept in a light-duty diesel engine over a large load range (3-16 bar net IMEP). In addition to validating these computational results, subsequent experiments at the Engine Research Center utilizing a single cylinder research engine based on a GM 1.9-liter diesel engine have progressed fundamental understanding of gasoline autoignition processes, and established the capability of critical controlling input parameters to better control GCI operation. The focus of this thesis can be divided into three segments: 1) establishment of operating requirements in the low-load operating limit, including operation sensitivities with respect to inlet temperature, and the capabilities of injection strategy to minimize NOx emissions while maintaining good cycle-to-cycle combustion stability; 2) development of novel three-injection strategies to extend the high load limit; and 3) having developed fundamental understanding of gasoline autoignition kinetics, and how changes in physical processes (e.g. engine speed effects, inlet pressure variation, and air-fuel mixture processes) affects operation, develop operating strategies to maintain robust engine operation. Collectively, experimental results have demonstrated the ability of GCI strategies to operate over a large load-speed range (3 bar to 17.8 bar net IMEP and 1300-2500 RPM, respectively) with low emissions (NOx and PM less than 1 g/kg-FI and 0.2 g/kg-FI, respectively), and low fuel consumption (gross indicated fuel consumption
Experimental And Computational Investigation Of Dual Fuel Diesel Natural Gas Rcci Combustion In A Heavy Duty Diesel Engine
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Author :
language : en
Publisher:
Release Date : 2018
Experimental And Computational Investigation Of Dual Fuel Diesel Natural Gas Rcci Combustion In A Heavy Duty Diesel Engine written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2018 with categories.
Abstract : Among the various alternative fuels, natural gas is considered as a leading candidate for heavy-duty applications due to its availability and applicability in conventional internal combustion diesel engines. Compared to their diesel counterparts natural gas fueled spark-ignited engines have a lower power density, reduced low-end torque capability, limited altitude performance, and ammonia emissions downstream of the three-way catalyst. The dual fuel diesel/natural gas engine does not suffer with the performance limitations of the spark-ignited concept due to the flexibility of switching between different fueling modes. Considerable research has already been conducted to understand the combustion behavior of dual fuel diesel/natural gas engines. As reported by most researchers, the major difficulty with dual fuel operation is the challenge of providing high levels of natural gas substitution, especially at low and medium loads. In this study extensive experimental and simulation studies were conducted to understand the combustion behavior of a heavy-duty diesel engine when operated with compressed natural gas (CNG) in a dual fuel regime. In one of the experimental studies, conducted on a 13 liter heavy-duty six cylinder diesel engine with a compression ratio of 16.7:1, it was found that at part loads high levels of CNG substitution could be achieved along with very low NOx and PM emissions by applying reactivity controlled compression ignition (RCCI) combustion. When compared to the diesel-only baseline, a 75% reduction in both NOx and PM emissions was observed at a 5 bar BMEP load point along with comparable fuel consumption values. Further experimental studies conducted on the 13 liter heavy-duty six cylinder diesel engine have shown that RCCI combustion targeting low NOx emissions becomes progressively difficult to control as the load is increased at a given speed or the speed is reduced at a given load. To overcome these challenges a number of simulation studies were conducted to quantify the in-cylinder conditions that are needed at high loads and low to medium engine speeds to effectively control low NOx RCCI combustion. A number of design parameters were analyzed in this study including exhaust gas recirculation (EGR) rate, CNG substitution, injection strategy, fuel injection pressure, fuel spray angle and compression ratio. The study revealed that lowering the compression ratio was very effective in controlling low NOx RCCI combustion. By lowering the base compression ratio by 4 points, to 12.7:1, a low NOx RCCI combustion was achieved at both 12 bar and 20 bar BMEP load points. The NOx emissions were reduced by 75% at 12 bar BMEP while fuel consumption was improved by 5.5%. For the 20 BMEP case, a 2% improvement in fuel consumption was achieved with an 87.5% reduction in NOx emissions. At both load points low PM emissions were observed with RCCI combustion. A low NOx RCCI combustion system has multiple advantages over other combustion approaches, these include; significantly lower NOx and PM emission which allows a reduction in aftertreatment cost and packaging requirements along with application of higher CNG substitution rates resulting in reduced CO2 emissions.
An Experimental Investigation Of Low Temperature Combustion Regimes In A Light Duty Engine
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Author :
language : en
Publisher:
Release Date : 2016
An Experimental Investigation Of Low Temperature Combustion Regimes In A Light Duty Engine written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2016 with categories.
Abstract : A continuous investigation on the improvement of internal combustion engines is necessary due to the stringent emission and fuel economy regulations. Low Temperature Combustion (LTC) is a promising field of research since it can simultaneously reduce NOx and soot while attaining high thermal efficiencies in automotive engines. A thorough study of several LTC regimes is necessary to understand the quantitative comparison and the extent of feasibility of these regimes functioning on an automotive engine. This thesis concentrates on an experimental investigation of three different LTC modes namely Homogeneously Charged Compression Ignition (HCCI), Partially Premixed Compression Ignition (PPCI) and Reactivity Controlled Compression Ignition (RCCI) on a 2.0-liter 4-cylinder gasoline engine. A detailed experimental study of the LTC regimes with over 2,500 data points on a GM 2.0 L Ecotec engine is performed to study the relationship among the engine variables, combustion and performance characteristics. The operating range extension of the engine for lean limit and load limit while functioning in each combustion mode is discussed through operating region maps. Performance metric maps for indicated specific fuel consumption (ISFC), brake specific fuel consumption (BSFC), thermal efficiency and exhaust temperature are developed and discussed. The optimized maps are developed for each LTC regime considering the best ISFC at each speed-load condition. Moreover, the behavior of the engine for each combustion mode is investigated and discussed through the trends observed for combustion phasing (CA10, CA50, CA90 and BD) and performance metrics (IMEP, indicated thermal efficiency, combustion efficiency). The results show that the RCCI combustion mode offers the best indicated thermal efficiency of 47% among the three LTC modes. The Start of Injection (SOI) of n-heptane is found as a dominant factor in order to determine the optimal combustion phasing. The results of a comparative study indicate that HCCI is more suitable for running the engine at low loads, PPCI for low-mid loads and RCCI for mid-high loads.
Light Duty Drive Cycle Simulations Of Diesel Engine Out Exhaust Properties For An Rcci Enabled Vehicle
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Author :
language : en
Publisher:
Release Date : 2013
Light Duty Drive Cycle Simulations Of Diesel Engine Out Exhaust Properties For An Rcci Enabled Vehicle written by and has been published by this book supported file pdf, txt, epub, kindle and other format this book has been release on 2013 with categories.
In-cylinder blending of gasoline and diesel fuels to achieve low-temperature reactivity controlled compression ignition (RCCI) can reduce NOx and PM emissions while maintaining or improving brake thermal efficiency compared to conventional diesel combustion (CDC). Moreover, the dual-fueling RCCI is able to achieve these benefits by tailoring combustion reactivity over a wider range of engine operation than is possible with a single fuel. However, the currently demonstrated range of stable RCCI combustion just covers a portion of the engine speed-load range required in several light-duty drive cycles. This means that engines must switch from RCCI to CDC when speed and load fall outside of the stable RCCI range. In this study we investigated the impact of RCCI as it has recently been demonstrated on practical engine-out exhaust temperature and emissions by simulating a multi-mode RCCI-enabled vehicle operating over two urban and two highway driving cycles. To implement our simulations, we employed experimental engine maps for a multi-mode RCCI/CDC engine combined with a standard mid-size, automatic transmission, passenger vehicle in the Autonomie vehicle simulation platform. Our results include both detailed transient and cycle-averaged engine exhaust temperature and emissions for each case, and we note the potential implications of the modified exhaust properties on catalytic emissions control and utilization of waste heat recovery on future RCCI-enabled vehicles.