Evaluation of massive exhaust gas recirculation and Miller cycle strategies for mixing-controlled low temperature combustion in a heavy duty diesel engine

Benajes, Jesús; Molina, Santiago; Novella, Ricardo; Belarte, Eduardo

doi:10.1016/j.energy.2014.04.083

Cited by 48 publications

(30 citation statements)

References 29 publications

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“…NOx reduction achieved with a Miller cycle strategy was limited primarily due to the small 347 impact on the in-cylinder flame temperature, as reported by Benajes et al [49]. The use of EGR can effectively curb NOx emissions but the fuel conversion efficiency could 352 be compromised when introducing EGR to Miller cycle operation at high engine loads.…”

Section: Test Conditionsmentioning

confidence: 99%

Variable valve actuation–based combustion control strategies for efficiency improvement and emissions control in a heavy-duty diesel engine

Guan

Pedrozo

Zhao

et al. 2019

International Journal of Engine Research

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High nitrogen oxide levels of the conventional diesel engine combustion often requires the introduction of exhaust gas recirculation at high engine loads. This can adversely affect the smoke emissions and fuel conversion efficiency associated with a reduction of the in-cylinder air-fuel ratio (lambda). In addition, low exhaust gas temperatures at low engine loads reduce the effectiveness of aftertreatment systems necessary to meet stringent emissions regulations. These are some of the main issues encountered by current heady-duty diesel engines. In this work, variable valve actuation–based advanced combustion control strategies have been researched as means of improving upon the engine exhaust temperature, emissions, and efficiency. Experimental analysis was carried out on a single-cylinder heady-duty diesel engine equipped with a high-pressure common-rail fuel injection system, a high-pressure loop cooled exhaust gas recirculation, and a variable valve actuation system. The variable valve actuation system enables a late intake valve closing and a second intake valve opening during the exhaust stroke. The results showed that Miller cycle was an effective technology for exhaust temperature management of low engine load operations, increasing the exhaust gas temperature by 40 °C and 75 °C when running engine at 2.2 and 6 bar net indicated mean effective pressure, respectively. However, Miller cycle adversely effected carbon monoxide and unburned hydrocarbon emissions at a light load of 2.2 bar indicated mean effective pressure. This could be overcome when combining Miller cycle with a second intake valve opening strategy due to the formation of a relatively hotter in-cylinder charge induced by the presence of internal exhaust gas recirculation. This strategy also led to a significant reduction in soot emissions by 82% when compared with the baseline engine operation. Alternatively, the use of external exhaust gas recirculation and post injection on a Miller cycle operation decreased high nitrogen oxide emissions by 67% at a part load of 6 bar indicated mean effective pressure. This contributed to a reduction of 2.2% in the total fluid consumption, which takes into account the urea consumption in aftertreatment system. At a high engine load of 17 bar indicated mean effective pressure, a highly boosted Miller cycle strategy with exhaust gas recirculation increased the fuel conversion efficiency by 1.5% while reducing the total fluid consumption by 5.4%. The overall results demonstrated that advanced variable valve actuation–based combustion control strategies can control the exhaust gas temperature and engine-out emissions at low engine loads as well as improve upon the fuel conversion efficiency and total fluid consumption at high engine loads, potentially reducing the engine operational costs.

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Section: Test Conditionsmentioning

confidence: 99%

Variable valve actuation–based combustion control strategies for efficiency improvement and emissions control in a heavy-duty diesel engine

Guan

Pedrozo

Zhao

et al. 2019

International Journal of Engine Research

View full text Add to dashboard Cite

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“…The Miller cycle has been proposed as another solution to comply with NOx regulations. This method is based on a decrease of the combustion temperatures by reducing the effective compression ratio through the air management settings [9,10]. The main disadvantage of this method is that it implies a worsening of engine performance.…”

Section: Introductionmentioning

confidence: 99%

Combustion noise analysis of partially premixed combustion concept using gasoline fuel in a 2-stroke engine

Broatch

Margot

Novella

et al. 2016

Energy

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ElsevierBroatch Jacobi, JA.; Margot, X.; Novella Rosa, R.; Gómez-Soriano, J. (2016). Combustion noise analysis of partially premixed combustion concept using gasoline fuel in a 2-stroke engine. Energy. 107:612-624. AbstractIn the last decade, different advanced combustion concepts based on generating totally or partially premixed conditions have been investigated in CI engines with the aim of achieving lower NOx and soot emissions. Most of the drawbacks inherent to this type of combustions, such as the combustion phasing control or combustion stability, can be mitigated by combining the PPC concept fueled by gasoline and a small 2-stroke HSDI engine. However, combustion noise issue remains unsolved while it is a critical aspect due to its strong influence in the customer purchasing decision and compliance of more stringent regulations. In this work, an analysis of the combustion noise generated by PPC combustion concept is performed in order to identify the most influential parameters and to define key paths for controlling the noise level. In addition, 3D CFD simulations have been performed to further understand the combustion noise generation mechanisms. Results evidence how the strong impact of the maximum pressure time-derivative achieved during combustion process renders all other sources of noise generation irrelevant. The trade-off between combustion noise and combustion efficiency of this PPC concept has been confirmed, while the intrinsic relation between such parameters and the engine efficiency has been also evaluated.

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“…In references [16,17], deeper Miller timing over 20°CA BBDC and an EGR rate which is higher than 20% were not presented, and Jesús Benajes confirmed how Miller cycle and EGR strategies are suitable for decreasing simultaneously NOx and soot emissions down to ultra-low levels, but he did not investigate the combination of these two technologies. For the Tier III emission regulation, NOx emissions still need to be further reduced if only one of the two technologies is adopted.…”

Section: Figurementioning

confidence: 99%

“…It can be concluded that the EGR system is an essential part of an engine concept in order to fulfill IMO Tier III NOx requirements, but only one Miller IVC (20°CA BBDC) was tested in his paper. In reference [17], a 1.8 l single-cylinder diesel engine was studied by Jesús Benajes by combining direct experimental data with the detailed information on the local in-cylinder conditions obtained from 3D-CFD simulations. The research was combined to compare the 10%-16% EGR and Miller (effective compression ratio = 8~14.4) strategies respectively in terms of the emissions, efficiency and the local combustion process.…”

Section: Figurementioning

confidence: 99%

A Numerical Study on Combustion and Emission Characteristics of a Medium-Speed Diesel Engine Using In-Cylinder Cleaning Technologies

Feng

et al. 2015

Energies

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Abstract:In order to clarify the potential of internal purification methods on medium speed diesel engines to meet the IMO Tier III nitrogen oxide (NOx) emission regulations, combined 1-D engine working cycle simulation and 3-D CFD simulation were conducted to predict the performance and emissions of the engine under different valve close timings, geometric compression ratios, injection timings, and Exhaust Gas Recirculation (EGR) rates. The numerical results show that, as the inlet valve close timing is advanced, NOx is reduced by as much as 27%, but the peak of premixed combustion heat release rate is increased; this can weaken the ability to reduce NOx with the Miller cycle. Moreover, the peak of premixed combustion heat release rate is reduced when the geometric compression ratio is increased to 15.4, and linking with injection timing by delaying 6°CA can further reduce NOx by 55.3% from the baseline. Finally, over 80% NOx reduction can be achieved when the above schemes are combined with over 15% EGR. The NOx and soot can be reduced simultaneously by using moderate Miller cycle combination with moderate EGR, and the results show a large reduction of NOx and moderate reduction of soot. This can be a feasible technical solution to meet Tier III regulations.

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Evaluation of massive exhaust gas recirculation and Miller cycle strategies for mixing-controlled low temperature combustion in a heavy duty diesel engine

Cited by 48 publications

References 29 publications

Variable valve actuation–based combustion control strategies for efficiency improvement and emissions control in a heavy-duty diesel engine

Variable valve actuation–based combustion control strategies for efficiency improvement and emissions control in a heavy-duty diesel engine

Combustion noise analysis of partially premixed combustion concept using gasoline fuel in a 2-stroke engine

A Numerical Study on Combustion and Emission Characteristics of a Medium-Speed Diesel Engine Using In-Cylinder Cleaning Technologies

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