Effects of Exhaust Gas Recirculation on Particulate Morphology for a Light-Duty Diesel Engine

Zhu, Jingyi; Lee, Kyeong

doi:10.4271/2005-01-0195

Cited by 14 publications

(15 citation statements)

References 17 publications

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“…Also relevant are the findings of Desantes et al [44] who have studied the effect of post injection on particle size distribution. Other researchers [46,47,48] have studied the effect of pilot injection, EGR fraction and fuel properties on size distribution. Such studies are also increasingly being performed by SI engine researchers [49], and are expected to increase as direct injected SI with turbocharging gains popularity.…”

Section: Introductionmentioning

confidence: 99%

“…Many researchers have examined simplified air-handling models have been proposed for control of transient emissions [32,33,34,35,36,37]. PN research, transient or steady state, is a relatively new area of research and hence investigators [38,39,40,41,42,43,44,45,46,47,48] have primarily focused their efforts at measuring transient particle size distributions, characterizing it, and studying sensitivities. Liu et al [38,39,40] have shown how transient engine parameters affect both size and concentration of emitted particles and how these are different from corresponding steady state emissions.…”

Section: Introductionmentioning

confidence: 99%

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Reduction of Transient Particulate Matter Spikes with Decision Tree Based Control

Brahma

2012

SAE Int. J. Engines

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Decision trees have been proposed as a basis for modifying table based injection to reduce transient particulate spikes during the turbocharger lag period. It has been shown that decision trees can detect particulate spikes in real time. In well calibrated electronically controlled diesel engines these spikes are narrow and are encompassed by a wider NO x spike. Decision trees have been shown to pinpoint the exact location of measured opacity spikes in real time thus enabling targeted PM reduction with near zero NO x penalty. A calibrated dimensional model has been used to demonstrate the possible reduction of particulate matter with targeted injection pressure pulses. Post injection strategy optimized for near stoichiometric combustion has been shown to provide additional benefits. Empirical models have been used to calculate emission tradeoffs over the entire FTP cycle. An empirical model based transient calibration has been used to demonstrate that such targeted transient modifiers are more beneficial at lower engine-out NO x levels.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reduction of Transient Particulate Matter Spikes with Decision Tree Based Control

Brahma

2012

SAE Int. J. Engines

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“…[24][25][26][27][28][29] The current work, in contrast with all these studies, focuses on the challenges of real-time opacity spike detection during the turbocharger lag period and the causative difficulties of estimating the volumetric efficiency and the cylinder-to-cylinder variation and proposes a simple solution for production diesel engines. PN research, transient or steady state, is a relatively new area of research and hence investigators [30][31][32][33][34][35][36][37][38][39][40] have primarily focused their efforts on measuring the transient particle size distributions, characterizing these distributions, and studying sensitivities. Liu et al [30][31][32] have shown how the transient engine parameters affect both the size and the concentration of emitted particles and how these are different from corresponding steady state emissions.…”

Section: Introductionmentioning

confidence: 99%

A decision-tree-based approach to smoke spike detection in a heavy-duty diesel engine

Brahma

2012

Proceedings of the Institution of Mechanical Engineers, Part D:

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Smoke spikes occurring during transient engine operation have detrimental health effects and increase fuel consumption by requiring more frequent regeneration of the diesel particulate filter. This paper proposes a decision tree approach to real-time detection of smoke spikes for control and on-board diagnostics purposes. A contemporary, electronically controlled heavy-duty diesel engine was used to investigate the deficiencies of smoke control based on the fuel-to-oxygenratio limit. With the aid of transient and steady state data analysis and empirical as well as dimensional modeling, it was shown that the fuel-to-oxygen ratio was not estimated correctly during the turbocharger lag period. This inaccuracy was attributed to the large manifold pressure ratios and low exhaust gas recirculation flows recorded during the turbocharger lag period, which meant that engine control module correlations for the exhaust gas recirculation flow and the volumetric efficiency had to be extrapolated. The engine control module correlations were based on steady state data and it was shown that, unless the turbocharger efficiency is artificially reduced, the large manifold pressure ratios observed during the turbocharger lag period cannot be achieved at steady state. Additionally, the cylinder-to-cylinder variation during this period were shown to be sufficiently significant to make the average fuel-to-oxygen ratio a poor predictor of the transient smoke emissions. The steady state data also showed higher smoke emissions with higher exhaust gas recirculation fractions at constant fuel-to-oxygen-ratio levels. This suggests that, even if the fuel-to-oxygen ratios were to be estimated accurately for each cylinder, they would still be ineffective as smoke limiters. A decision tree trained on snap throttle data and pruned with engineering knowledge was able to use the inaccurate engine control module estimates of the fuel-to-oxygen ratio together with information on the engine control module estimate of the exhaust gas recirculation fraction, the engine speed, and the manifold pressure ratio to predict 94% of all spikes occurring over the Federal Test Procedure cycle. The advantages of this non-parametric approach over other commonly used parametric empirical methods such as regression were described. An application of accurate smoke spike detection in which the injection pressure is increased at points with a high opacity to reduce the cumulative particulate matter emissions substantially with a minimum increase in the cumulative nitrogrn oxide emissions was illustrated with dimensional and empirical modeling.

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“…As the engine load increased during diesel operation, the primary diameter decreased slightly. The growth of primary particle depends on the competition between oxidation and nucleation [38,39]. The average diameter of the primary particle measured under stoichiometric and fuel rich condition were 14.7 nm and 14.8 nm respectively.…”

Section: Cascade Impactormentioning

confidence: 99%

“…Zhu et al investigated the effects of exhaust gas recirculation (EGR) on morphology of PM emitted from a light-duty diesel engine [39]. A rapid prototyping electronic control system (RPECS) was developed to operate a 1.7 liter light duty engine at various EGR rates under different conditions (i.e.…”

Section: Dmsmentioning

confidence: 99%

An Investigation of Diesel PM Particle Morphology Using TEM and SEM

Vedula¹

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This research investigates the effect of engine load and combustion mode on the size, shape and microstructure of PM particles of two diesel engines using a scanning mobility particle sizer (SMPS), and electron microscopes including scanning electron microscope (SEM) and transmission electron microscope (TEM). The effect of engine load on the morphology of PM particle was investigated using a 2004 MACK MP7-355E heavy-duty diesel engine. The effect of combustion mode on the morphology of the PM particles was preliminarily examined using 2005 Opel 1.9 L light-duty diesel engine. The SEM images were processed using ImageJ V: 1.44o software to obtain a set of parameters based on the projected area. These include the maximum length, maximum width, project area equivalent diameter, shape descriptor, fractal dimension, and the size of primary PM particles. The TEM images were processed to obtain the micro-structure and chemical composition of PM particles. The SEM images obtained in this research revealed the diverse morphology of PM particles formed in heavy-duty diesel engine. The operation at low load tends to form small sphere-like PM particles compared to medium and high load operation featured with large and chain-like PM particles. The projected area equivalent diameter of PM particles observed was in the range of 43.7 to 167.4 nm and 66.4 to 688 nm for operation at 20% and 100% load respectively. The PM particles smaller than 43 nm observed using SMPS were not observed using SEM methods. The projected area equivalent diameter of PM particles from the light duty engine during PCCI mode was smaller in size compared to the PM particles observed under normal operation. The fractal dimension of this heavy-duty diesel engine observed was 1.82, indicating spherical PM particles. The fractal dimension for the light duty engine was 1.65 and 1.7 for the traditional diesel and PCCI mode, respectively, indicating more spherical particles during PCCI mode. The TEM images were processed to obtain the compositions and microstructure of the PM particles. The PM particles observed contain mainly carbon as well as inorganic and metallic elements such as Ca, Mg, Zn, P and Si from engine oil, Al and Fe from engine wear, and S from fuel and lubricating oil. The compositions of PM particles were also found to vary significantly from particle to particle observed under identical operating conditions indicating the random burning of lubrication oil droplets and its effect on the formation of PM particles. The microstructure of primary particles from the heavy duty diesel engine exhibited two types of

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Effects of Exhaust Gas Recirculation on Particulate Morphology for a Light-Duty Diesel Engine

Cited by 14 publications

References 17 publications

Reduction of Transient Particulate Matter Spikes with Decision Tree Based Control

Reduction of Transient Particulate Matter Spikes with Decision Tree Based Control

A decision-tree-based approach to smoke spike detection in a heavy-duty diesel engine

An Investigation of Diesel PM Particle Morphology Using TEM and SEM

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