Evaluation of Valve Train Variability in Diesel Engines

Ratzberger, Reinhard; Kraxner, Thomas; Pramhas, Jochen; Hadl, Klaus; Eichlseder, Helmut; Buergler, Ludwig

doi:10.4271/2015-24-2532

Cited by 15 publications

(5 citation statements)

References 18 publications

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“…8,29,30 This is mainly attributed to the lower in-cylinder mass resulted from the delayed intake valve closing (IVC) timing, leading to a lower in-cylinder heat capacity. The experimental and numerical study by Ratzberger et al 31 demonstrated the potential of an early exhaust valve opening (EEVO) and a LIVC for exhaust thermal management. Garg et al 32 experimentally examined the influence of in-cylinder charge control via early and late IVC events at a low engine load.…”

Section: Introductionmentioning

confidence: 99%

Miller cycle combined with exhaust gas recirculation and post–fuel injection for emissions and exhaust gas temperature control of a heavy-duty diesel engine

Guan

Pedrozo

Zhao

et al. 2019

International Journal of Engine Research

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Miller cycle has been shown as a promising engine strategy to reduce in-cylinder nitrogen oxide (NOx) formation during the combustion process and facilitate its removal in the aftertreatment systems by increasing the exhaust gas temperature. However, the level of NOx reduction and the increase in exhaust gas temperature achieved by Miller cycle alone is limited. Therefore, research was carried out to investigate the combined use of Miller cycle with other advanced combustion control strategies in order to minimise the NOx emissions and the total cost of ownership. In this article, the effects of Miller cycle, exhaust gas recirculation, and post-injection were studied and analysed on the performance and exhaust emissions of a single cylinder heavy-duty diesel engine. A cost–benefit analysis was carried out using the corrected total fluid efficiency, which includes the estimated urea solution consumption in the NOx aftertreatment system as well as the fuel consumption. The experiments were performed at a low load of 6 bar net indicated mean effective pressure. The results showed that the application of a Miller cycle–only strategy with a retarded intake valve closing at −95 crank angle degree after top dead centre decreased NOx emissions by 21% to 6.0 g/kW h and increased exhaust gas temperature by 30% to 633 K when compared to the baseline engine operation. This was attributed to a reduction in compressed gas temperature by the lower effective compression ratio and the in-cylinder mass trapped due to the retarded intake valve closing. These improvements, however, were accompanied by a fuel-efficiency penalty of 1%. A further reduction in the level of NOx from 6.0 to 3.0 g/kW h was achieved through the addition of exhaust gas recirculation, but soot emissions were more than doubled to 0.022 g/kW h. The introduction of a post-injection was found to counteract this effect, resulting in simultaneous low NOx and soot emissions of 2.5 and 0.012 g/kW h, respectively. When taking into account the urea consumption, the combined use of Miller cycle, exhaust gas recirculation, and post-injection combustion control strategies were found to have relatively higher corrected total fluid efficiency than the baseline case. Thus, the combined ‘Miller cycle + exhaust gas recirculation + post-injection’ strategy was the most effective means of achieving simultaneous low exhaust emissions, high exhaust gas temperature, and increased corrected total fluid efficiency.

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Section: Introductionmentioning

confidence: 99%

Miller cycle combined with exhaust gas recirculation and post–fuel injection for emissions and exhaust gas temperature control of 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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“…Variable valve actuation (VVA) offers an alternative approach to increasing the EGT as well as a number of other benefits. Ratzberger et al 19 carried out an experimental and numerical study to evaluate the ability of an early exhaust valve opening (EEVO) and a late intake valve closing (LIVC) for exhaust thermal management. An increase in EGT was realized by LIVC; however, the dropped pressure and temperature at the start of combustion led to poor combustion stability and problematic unburnt HC emission.…”

Section: Introductionmentioning

confidence: 99%

Exploring alternative combustion control strategies for low-load exhaust gas temperature management of a heavy-duty diesel engine

Guan

Zhao

Ban

et al. 2018

International Journal of Engine Research

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6The employment of aftertreatment systems in modern diesel engines has become indispensable 7 in order to meet the stringent emissions regulations. However, a minimum exhaust gas 8 temperature (EGT) of approximately 200°C must be reached to initiate the emissions control 9 operations. Low load engine operations usually result in relatively low EGT, which lead to 10 reduced or no exhaust emissions conversion. In this context, this study investigated the use of 11 different combustion control strategies to explore the trade-off between EGT, fuel efficiency 12 and exhaust emissions. 13 14The experiments were carried out on a single cylinder common rail heavy-duty diesel engine 15 at a light load of 2.2 bar indicated mean effective pressure. Strategies include the late intake 16 valve closure (LIVC) timing, intake throttling, late injection timing (Tinj), lower injection 17 pressure (Pinj), and internal exhaust gas recirculation (iEGR) as well as external EGR (eEGR) 18 were investigated. Results showed that the use of eEGR and lower Pinj were not effective in 19 increasing EGT. Although the use of late Tinj could result in a higher EGT, the delayed 20 combustion phase led to the highest fuel efficiency penalty. Intake throttling and iEGR allowed 21 for an increase in EGT by 42°C and 52°C at the expense of 7.2% and 17% fuel consumption 22 penalties, respectively. In comparison, LIVC strategy achieved the best trade-off between EGT 23 and ISFC, increasing the EGT by 52°C and the fuel consumption penalty by 5.3% while 24 reducing NOx and soot emissions simultaneously. When the IVC timing was delayed to after 25 -107 CAD ATDC, however, the combustion efficiency deteriorated, and hence very high HC 26 and CO emissions. This could be overcome by combining iEGR with LIVC to increase the in-27 cylinder combustion temperature for a more complete combustion. The results demonstrated 28 that the "LIVC + iEGR" strategy can be the most effective means, increasing the EGT by 62°C 29 with small penalty in the fuel consumption of 4.6% and soot emission reduction by 85%. 30 Meanwhile, maintaining high combustion efficiency as well as low HC and CO emissions of 31 diesel engines. 32 Keywords 33 Heavy-duty diesel engine, variable valve actuation, late intake valve closing, internal EGR, 34 exhaust temperature, exhaust emissions 35 36 42 combustion produces a large amount of particulate matter (PM) in the fuel rich burning region 43 and high concentration of nitrogen oxide (NOx) in the high temperature zones [1]. In order to 44 meet the Euro VI or equivalent emission regulations of 0.4 g/kW•h NOx and 0.010 g/kW•h PM 45 [2], significant reduction of these pollutants by in-cylinder combustion technologies and 46 emission control aftertreatment systems are required. 47 48 Advanced combustion modes such as Homogeneous Charge Compression Ignition (HCCI), 49 Pre-mixed Charge Compression Ignition (PCCI), and Low Temperature Combustion (LTC) 50 are able to achieve a reduction in NOx and soot simultaneously, through reducing the peak in-51...

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“…These conflicting demands require a precisely optimized combustion system and underline the need of a holistic approach. To achieve a rapid engine and EAS warm-up several approaches can be applied: Internal measures such as valve train variabilities with an early exhaust valve opening [6] or an intake valve re-opening [7] help to increase the exhaust gas temperature during cold run. Furthermore, the use of thermal barrier coatings and dedicated combustion modes contribute to a faster engine warm-up [8,9].…”

Section: Introductionmentioning

confidence: 99%

Cold emission optimization of a diesel- and alternative fuel-driven CI engine

Nenning

Eichlseder

Egert

2021

Automot. Engine Technol.

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This paper deals with the emission optimization of a compression ignition (CI) engine during cold ambient operation. Hence, in the present study, the effect of different injector nozzle geometries and pilot injection strategies, but also the influence of intake swirl, rail pressure, exhaust gas recirculation (EGR) as well as EGR cooling on the emission behavior during cold run are investigated. Therefore, test bed experiments under steady-state cold conditions are conducted on a state-of-the-art CI single cylinder research engine (SCRE) with approximately 0.5 l swept volume representing the typical passenger car (PC) cylinder size. The cold charge air temperature of down to −8 $$^{\circ }\hbox { C}$$ ∘ C and a low engine coolant and lube oil temperature represent a cold run close to reality. For emulating the higher friction of a typical 4-cylinder PC engine during cold run, the indicated mean effective pressure (IMEP) is increased according to a specifically developed equation and the turbocharger main equation is solved permanently to adjust the gas exchange loss. To take account of a potential future tightening of emission legislation, in addition to limited exhaust gas emissions, non-limited emissions such as carbonyls are measured as well. Since alternative fuels are able to make a significant contribution to the defossilisation of transportation, an oxygen-containing fuel, consisting of 100 % renewable blend components (HVO, ethers and alcohols) and fulfilling the EN 590 legislation is investigated under the same cold conditions in addition to the research on conventional diesel fuel.

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Evaluation of Valve Train Variability in Diesel Engines

Cited by 15 publications

References 18 publications

Miller cycle combined with exhaust gas recirculation and post–fuel injection for emissions and exhaust gas temperature control of a heavy-duty diesel engine

Miller cycle combined with exhaust gas recirculation and post–fuel injection for emissions and exhaust gas temperature control of a heavy-duty diesel engine

Exploring alternative combustion control strategies for low-load exhaust gas temperature management of a heavy-duty diesel engine

Cold emission optimization of a diesel- and alternative fuel-driven CI engine

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