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Journal ArticleDOI

Influence of high rates of supplemental cooled EGR on NOx and PM emissions of an automotive HSDI diesel engine using an LP EGR loop

TL;DR: In this article, a low-pressure EGR loop is implemented on a standard 2.0 l automotive high-speed direct injection (HSDI) turbocharged diesel engine to study the influence of high rates of supplemental cooled EGR on NOx and PM emissions.
Abstract: Previous experimental studies on diesel engine have demonstrated the potential of exhaust gas recirculation (EGR) as an in-cylinder NOx control method. Although an increase in EGR at constant boost pressure (substitution EGR) is accompanied with an increase in particulate matter (PM) emissions in the conventional diesel high-temperature combustion (HTC), the recirculation of exhaust gases supplementary to air inlet gas (supplemental EGR) by increasing the boost pressure has been suggested as a way to reduce NOx emissions while limiting the negative impact of EGR on PM emissions. In the present work, a low-pressure (LP) EGR loop is implemented on a standard 2.0 l automotive high-speed direct injection (HSDI) turbocharged diesel engine to study the influence of high rates of supplemental cooled EGR on NOx and PM emissions. Contrary to initial high-pressure (HP) EGR loop, the gas flow through the turbine is unchanged while varying the EGR rate. Thus, by closing the variable geometry turbine (VGT) vanes, higher boost pressure can be reached, allowing the use of high rates of supplemental EGR. Furthermore, recirculated exhaust gases are cooled under 50°C and water vapour is condensed and taken off from the recirculated gases. An increase in the boost pressure at a given inlet temperature and dilution ratio (DR) results in most cases an increase in NOx emissions and a decrease in PM emissions. The result of NOx–PM trade-off, while varying the EGR rate at fixed inlet temperature and boost pressure depends on the operating point: it deteriorates at low load conditions, but improves at higher loads. Further improvement can be obtained by increasing the injection pressure. A decrease by approximately 50% of NOx emissions while maintaining PM emission level, and brake specific fuel consumption can be obtained with supplemental cooled EGR owing to an LP EGR loop, compared with the initial engine configuration (HP moderately cooled EGR). Copyright © 2008 John Wiley & Sons, Ltd.
Citations
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Journal ArticleDOI
TL;DR: In this paper, a comprehensive investigation of different approaches applying to biodiesel fueled engine like biodiesel additives, exhaust gas recirculation (EGR), water injection (WI), emulsion technology (ET), injection strategy modification, simultaneous technologies (ST), combustion chamber geometry modification and low temperature combustion (LTC) mode is performed.
Abstract: Due to the shortage of the conventional fossil fuels and air pollution from combustion, new, sustainable and cleaner fuel resources are urgently required. Biodiesel has been introduced as a potential and alternative fuel for years. Biodiesel can be produced from different sources such as vegetable oils, animal fat, waste oil, etc. All of them are renewable and do not affect the food security. When biodiesel is used as a fuel resource for diesel engines, the performance and emission characteristics such as brake thermal efficiency (BTE), brake specific fuel consumption (BSFC) and brake power are almost maintained while hydrocarbons (HC), carbon monoxide (CO), and particulate matter (PM) is decreased significantly. However, higher NOx concentration is observed. This disadvantage of using biodiesel or biofuels in general is improved in recent years. The purpose of this work is to do a comprehensive investigation of different approaches applying to biodiesel fueled engine like biodiesel additives, exhaust gas recirculation (EGR), water injection (WI), emulsion technology (ET), injection strategy modification, simultaneous technologies (ST), combustion chamber geometry modification and low temperature combustion (LTC) mode. By the way, the impacts of these technologies on engine performance and emission characteristics are summarized. Upon the comparison, using LTC mode is more efficient and feasible than the others. It can reduce both NOx and PM emissions simultaneously by up to 95% and 98%, respectively, while engine performance is slightly reduced. Looking inside the LTC mode, the most efficient model is the reactivity controlled compression ignition (RCCI) combustion system. Applying RCCI combustion model might lead to the increase of CO and HC emissions, but this issue can be easily solved by using some available technologies.

238 citations

Journal ArticleDOI
01 Sep 2010-Energy
TL;DR: In this paper, an experimental study conducted on a modern high speed common-rail automotive Diesel engine in order to evaluate the effects on combustion and pollutant emissions of water injected as a fine mist in the inlet manifold is presented.

177 citations

Journal ArticleDOI
TL;DR: In this article, the impact of different NOx mitigation technologies on biodiesel-fueled diesel engine performance and emissions is analyzed critically and different methods of their implementation are shown, and the results show that using low temperature combustion (LTC) is more efficient and promising than the others because of its capability to reduce both NOx and particulate matter (PM) emissions simultaneously without significant penalties with regard to engine performance.

135 citations


Cites background from "Influence of high rates of suppleme..."

  • ...Exhaust gas recirculation (EGR) So far, EGR has been the most frequently mentioned NOx mitigation technology for diesel engines fueled with both diesel and biodiesel [112–120]....

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Journal ArticleDOI
01 Nov 2011-Fuel
TL;DR: In this paper, an experimental study is conducted on a modern automotive 1.5l HSDI Diesel engine while injecting a water-in-diesel emulsion (WDE) with a volumetric water-to-fuel ratio of 25.6%.

125 citations

Journal ArticleDOI
TL;DR: In this article, a literature review on previous proposed strategies in order to reduce the emissions of diesel engines is presented, which includes combustion management, fuel additives and after-treatment technology.
Abstract: The present study is a literature review on previous proposed strategies in order to reduce the emissions of diesel engines. In this review, the results of effective strategies include; combustion management, fuel additives and after-treatment technology which are reported in various research studies are discussed. The overall results showed that using one strategy can not reduce all the emissions of diesel engines. However, employing several strategies simultaneously can reduce all the diesel engine emissions. The result from a survey showed that the best proposed solution for reduction of diesel engine pollutants is using biofuels, which consist of a combination of diesel, biodiesel and ethanol. Furthermore, synthesis of metal-based nano-catalysts must be used in these fuels; engines with turbocharger must be used and high compression ratio along with the increase of fuel injection pressure must be considered. Furthermore, exhaust gas recirculation (EGR) system must be deployed in engine for ensuring in the minimization of pollutants; diesel oxidation catalyst (DOC), elective catalytic reduction (SCR) and also diesel particulate filter (DPF) must be utilized.

99 citations

References
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Proceedings ArticleDOI
TL;DR: In this paper, the authors examined the effect of ambient gas density and fuel vaporization on the penetration and dispersion of diesel sprays over a gas density range spanning nearly two order of magnitude.
Abstract: Ambient gas density and fuel vaporization effects on the penetration and dispersion of diesel sprays were examined over a gas density range spanning nearly two order of magnitude. This range included gas densities more than a factor of two higher than top-dead-center conditions in current technology heavy-duty diesel engines. The results show that ambient gas density has a significantly larger effect on spray penetration and a smaller effect on spray dispersion than has been previously reported. The increased dependence of penetration on gas density is shown to be the result of gas density effects on dispersion. In addition, the results show that vaporization decreases penetration and dispersion by as much as 20% relative to non-vaporizing sprays; however, the effects of vaporization decrease with increasing gas density. Characteristic penetration time and length scales are presented that include a dispersion term that accounts for the increased dependence of penetration on ambient density. These penetration time and length scales collapse the penetration data obtained over the entire range of conditions examined in the experiment into two distinct non-dimensional penetration curves: one for the non-vaporizing conditions and one for the vaporizing conditions. Comparison of the two nondimensional penetration curves to a theoretical penetration correlation for non-vaporizing sprays helped isolate and explain the effects of droplets and vaporization on penetration. The theoretical penetration correlation was derived using the penetration time and length scales and simple model for a non-vaporizing spray that has been previously presented in the literature. The correlation is in good agreement with the non-vaporizing data from this experiment and other commonly quoted penetration data sets. It also provides a potential explanation for much of scatter in the penetration predicted by various correlations in the literature.

965 citations

Proceedings ArticleDOI
05 Mar 2001

821 citations

Journal ArticleDOI
TL;DR: In this paper, a conceptual model based on in-cylinder soot and combustion measurements was used to explain the trends seen in exhaust particulate emissions and showed that diesel engine emissions control involves multi-injection combustion strategies which are transforming the picture of diesel combustion rapidly into a series of low temperature, stratified charge, premixed combustion events where NO x formation is avoided by leaning the mixture or increasing air entrainment prior to ignition.

747 citations

Journal ArticleDOI
TL;DR: In this paper, the paths and limits to reduce NOx emissions from Diesel engines are briefly reviewed, and the inevitable uses of EGR are highlighted, as well as new concepts regarding EGR stream treatment and EGR hydrogen reforming.

678 citations

Proceedings ArticleDOI
01 Feb 1979

668 citations