Multidimensional modeling of the effect of Exhaust Gas Recirculation (EGR) on exergy terms in an HCCI engine fueled with a mixture of natural gas and diesel

Jafarmadar, Samad; Nemati, Peyman; Khodaie, Rana

doi:10.1016/j.enconman.2015.08.014

Cited by 35 publications

(11 citation statements)

References 33 publications

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“…FLT analysis does not recognize irreversibilities across systems' components, thus it provides limited insight for ICE optimal control. A large number of studies [2,3,4,5,6,7,8,9,10,11,12,13,14] have analyzed SLT in ICEs. Figure 1 illustrates a summary of the ICE studies in the literature based on the exergy and SLT.…”

Section: Introductionmentioning

confidence: 99%

“…As shown in Figure 1, depending on the use of exergy in ICEs, studies can be categorized into three main groups: (i) system analysis, (ii) design optimization, and (iii) controls. The first group consists of exergy analysis for (a) whole engine [2,3,4,5], (b) combustion phasing [6,7], (c) closed engine cycle [8,9,10,13], (d) combustion process [15,11,16], and (e) exhaust heat recovery [17,18,19]. For instance in [3], application of the SLT and its equations have been provided for different types of internal combustion engines and their subsystems (e.g., turbocharger, inlet and exhaust manifolds).…”

Section: Introductionmentioning

confidence: 99%

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Optimal exergy-based control of internal combustion engines

et al. 2016

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Exergy or availability is defined as the maximum useful work during a process. This metric has been used to analyze and understand loss mechanisms of Internal Combustion Engines (ICEs). In this paper, an optimal control method based on exergy is introduced for transient and steady state operation of ICEs. First, an exergy model is developed for a single cylinder Ricardo engine. The ICE exergy model is based on the Second Law of Thermodynamics (SLT) and characterizes irreversibilities. Such quantifications are not identified in the First Law of Thermodynamics (FLT) analysis. For steady-state operation of the ICE, a set of 175 different operating conditions is used to construct the SLT efficiency maps. Two different SLT efficiency maps are generated depending on the applications whether work, or Combined Power and Exhaust Exergy (CPEX) is the desired output. To include transient ICE operation, a model to predict exergy loss/destruction during engine transients is developed. The sources of exergy destruction/loss are identified for a Homogeneous Charge Compression Ignition (HCCI) engine. Based on the engine operating conditions (i.e., steady-state or transient) SLT efficiency contour maps or predicted exergy losses are determined at every given engine load. An optimization algorithm is proposed to find the optimum combustion phasing to maximize the SLT efficiency. Application of the optimization algorithm is illustrated for combustion phasing control. The results show that using the exergy-based optimal control strategy leads to an average of 6.7% fuel saving and 8.3 % exergy saving compared to commonly used FLT based combustion control in which a fixed combustion phasing (e.g., 8 • aT DC) is used.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimal exergy-based control of internal combustion engines

et al. 2016

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“…Restricted dead state is described as a condition in which the mixture would be at T 0 , P 0 and is the actual chemical composition of the mixture but true dead state is defined as a state in which the mixture would be at T 0 , P 0 and a composition equal to air. 48 Chemical availability is divided into oxidation availability, reduction availability, and diffusion availability. 36 Therefore, the total chemical availability is:…”

Section: Second-law Equation Analysismentioning

confidence: 99%

Availability analysis on combustion of n-heptane and isooctane blends in a reactivity controlled compression ignition engine

Mohebbi

Reyhanian

Ghofrani

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part D:

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Unfortunately, energy demands and destruction of the environment from uncontrolled manipulation of fossil fuels have increased. Climate change concerns have resulted in the rapid use of new, alternative combustion technologies. In this study, reactivity controlled compression ignition (RCCI) combustion, which can simply be exploited in internal combustion (IC) engines, is investigated. To introduce and identify extra insightful information, an exergy-based study was conducted to classify various irreversibility and loss sources. Multidimensional models were combined with the primary kinetics mechanism to investigate RCCI combustion, incorporating the second law of thermodynamics. The n-heptane, a highly reactive fuel, was supplied by direct injection into the cylinder, whereas premixed fuel was supplied through the intake port in an isooctane/n-heptane RCCI engine. For five n-heptane increments (5%, 7.5%, 15%, 25%, and 40%) and six different exhaust gas recirculation (EGR) rates (0%, 10%, 20%, 30%, 40%, and 50%), accumulation of different exergy terms was calculated. The results show that as EGR introduction increases from 0% to 50%, the exergy destruction increases from 21.1% to 28.9%. Furthermore, the value of exhaust thermomechanical exergy decreases from 18.4% to 14.4% of the mixture fuel chemical exergy. Among the five different high reactive fuel mass regimes, the 40% n-heptane mass fraction has the major heat transfer exergy owing to its advanced CA50 that exerts a unique influence on cylinder charge temperature of heat transfer layer. The utilization efficiency of exhaust in RCCI is less affected by the variation of reactive fuel mass fraction by contrast; it will significantly influence heat transfer availability. This study revealed that with increasing reactive fuel (n-heptane) from 7.5% to 40% the irreversibility decreased from 28.6% to 25.8% and the second law efficiency first increased from 43.2% to 44.6% at 15% n-heptane then decreased to 42.9% at 40% n-heptane.

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“…Homogenous charge compression ignition (HCCI) mode of combustion is an alternative combustion strategy for conventional diesel engine that offers the potential to high power output with significantly reduced exhaust emissions of NO x and Particulate matter [1,2]. HCCI engines encounter low temperatures during the combustion, producing high levels of emissions of HC and CO [3].…”

Section: Introductionmentioning

confidence: 99%

A Numerical Study on the Effects of Exhaust Gas Recirculation Temperature on Controlling Combustion and Emissions of a Diesel Engine running on HCCI Combustion Mode

Rather

Wani

2018

International Journal of Automotive Science and Technology

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In this study a comprehensive study is carried out numerically on a single cylinder four-stroke Diesel engine operating in homogenous charge compression ignition (HCCI) mode of combustion for the effects of exhaust gas recirculation (EGR) temperature and percentage on the combustion and emission characteristics. An advanced version of ANSYS IC Engine FORTE coupled with highly efficient and detailed pre-defined industry standard chemical kinetics CHEMKIN is used to solve the chemical reaction mechanism and species thermodynamic data. The analysis was carried out at three different EGR temperatures of 363K, 404K and 513K for 10%, 20% , 30%, 40% and 50% EGR each. The results predicted that the combustion ignition timing is advanced by increasing the EGR temperature. The effect of low EGR temperature is predominant at higher percentages of EGR. It was also found that the CO and UHC levels nearly kept constant with an increase in EGR temperature the NOx levels increase linearly with an increase in EGR temperature. The HCCI combustion in diesel engine can be controlled by adjusting the temperature and mass percentage of exhaust gas recirculation while retaining lower NOx emissions and very little increase in CO and unburnt hydrocarbons.

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Multidimensional modeling of the effect of Exhaust Gas Recirculation (EGR) on exergy terms in an HCCI engine fueled with a mixture of natural gas and diesel

Cited by 35 publications

References 33 publications

Optimal exergy-based control of internal combustion engines

Optimal exergy-based control of internal combustion engines

Availability analysis on combustion of n-heptane and isooctane blends in a reactivity controlled compression ignition engine

A Numerical Study on the Effects of Exhaust Gas Recirculation Temperature on Controlling Combustion and Emissions of a Diesel Engine running on HCCI Combustion Mode

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