Turbine and exhaust ports thermal insulation impact on the engine efficiency and aftertreatment inlet temperature

Luján, José Manuel; Serrano, José Ramón; Diesel, Bárbara

doi:10.1016/j.apenergy.2019.02.043

Cited by 27 publications

(19 citation statements)

References 40 publications

(38 reference statements)

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“…Unfortunately, the most critical emission is methane as it has a high reaction barrier which leads to rather poor reaction rates over platinum or palladium oxidation catalysts, especially at lower catalyst temperature levels 58 such as we see here. Exhaust port and turbine insulation, which is not used here, may help to improve the thermal situation, 61 but this approach alone will not solve the problem. There are some approaches being discussed in the scientific community to enable efficient catalytic methane oxidation at lower temperatures, for example, the use of zeolites, 62,63 graphene confinements 64 or electric fields, 65 but no solution is yet commercially available.…”

Section: Resultsmentioning

confidence: 99%

Efficient light-duty engine using turbulent jet ignition of lean methane mixtures

Soltic

Hilfiker

Hänggi

2019

International Journal of Engine Research

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Diesel engines use diffusion-controlled combustion of a high-reactivity fuel and offer high efficiencies because they combine lean combustion with a high compression ratio. For low-reactivity fuels such as gasoline or natural gas, premixed combustion is used, which leads to lower efficiency levels as usually stoichiometric combustion is combined with lower compression ratios. Trying to apply diesel-like process parameters to low-reactivity fuels inevitably leads to problems with classical spark ignition systems as they are not able to establish robust flame propagation for such hard-to-ignite conditions. One possibility to enable fast combustion for diluted mixtures at high pressure levels is to establish ignition in a prechamber and ignite the charge of the main combustion chamber using the turbulent jets exiting the prechamber. In this study, the experimental results of a prechamber-equipped four-cylinder natural gas engine with 2 L displacement are discussed in detail. In the majority of the engine map, auxiliary fueling is used in the prechamber and a global air–fuel equivalence ratio λ is set to 1.7. At full load, a λ of 1.5 is applied without auxiliary prechamber fueling. The experiments show that such a setup is able to achieve brake efficiency levels of above 45% while maintaining peak brake mean effective pressure levels above 20 bar. At high load conditions, cylinder pressure levels at ignition timing achieve more than 80 bar and cylinder peak pressures of around 180 bars occur. The technology proved to enable robust and very fast combustion at comparably low NOx levels. A remaining challenge for the on-road use of such a technology is the reduction of the methane emissions at lean conditions.

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Section: Resultsmentioning

confidence: 99%

Efficient light-duty engine using turbulent jet ignition of lean methane mixtures

Soltic

Hilfiker

Hänggi

2019

International Journal of Engine Research

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“…On the other hand, the turbocharger and ATS sub-models available in GT-POWER were replaced by dedicated user-functions available in OpenWAM [32], which is an open-source gas dynamics software developed by CMT-Motores Térmicos [33]. The turbocharger sub-model was applied aimed at a more precise simulation of the heat transfer [34] and the mechanical losses [35] in the turbocharger thus contributing to improving the prediction of the temperature at the turbine outlet [31].…”

Section: Modelling Toolsmentioning

confidence: 99%

“…The gas composition at the DOC inlet and outlet was measured by a Horiba Mexa 7100 gas analyser and AVL 439 opacimeter. A detailed calibration of the engine model is provided in [31]. The predictive capabilities of the engine model were improved by specific sub-models.…”

Section: Introductionmentioning

confidence: 99%

Late Fuel Post-Injection Influence on the Dynamics and Efficiency of Wall-Flow Particulate Filters Regeneration

et al. 2019

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Late fuel post-injections are the most usual strategy to reach high exhaust temperature for the active regeneration of diesel particulate filters. However, it is important to optimise these strategies in order to mitigate their negative effect on the engine fuel consumption. This work aims at understanding the influence of the post-injection parameters, such as its start of injection and its fuel quantity, on the duration of the regeneration event and the fuel consumption along it. For this purpose, a set of computational models are employed to figure out in a holistic way the involved phenomena in the interaction between the engine and the exhaust gas aftertreatment system. Firstly, an engine model is implemented to evaluate the effect of the late fuel post-injection pattern on the gas properties at the exhaust aftertreatment system inlet in different steady-state operating conditions. These are selected to provide representative boundary conditions of the exhaust gas flow concerning dwell time, exhaust temperature and O 2 concentration. In this way, the results are later applied to the analysis of the diesel oxidation catalyst and wall-flow particulate filter responses. The dependence of the diesel particulate filter (DPF) inlet temperature is discussed based on the efficiency of each post-injection strategy to increase the exhaust gas temperature. Next, the influence on the dynamics of the regeneration of the post-injection parameters through the change in gas temperature and O 2 concentration is finally studied distinguishing the pre-heating, maximum reactivity and late soot oxidation stages as well as the required fuel consumption to complete the regeneration process.

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“…Meng and Bai et al emphasized that the exhaust temperature is critical for DPF regeneration, and they applied experimental methods to optimize engine thermal management control strategies to achieve a specific exhaust gas temperature for DPF on PN control to meet the strict PN emission levels [9,10]. Luján and Holmer et al applied engine calibration to control the aftertreatment inlet exhaust gas temperature and used modeling and analytical methods on the literature regarding what is critical for aftertreatment in order to reach the specific exhaust gas temperatures for the best conversion efficiency [11,12] Aftertreatment packaging design is another key area of research in existing studies. Liu et al emphasized the importance of the diesel exhaust aftertreatment system design, especially the SCR system related packaging design, which affects SCR emission performance [13].…”

Section: Introductionmentioning

confidence: 99%

Research on Aftertreatment Inlet_Outlet Insulation for A Nonroad Middle Range Diesel Engine

2020

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Diesel exhaust aftertreatment systems are required for meeting China StageIV emission regulations. This paper addresses an aftertreatment system designed to meet the China StageIV emission standards for nonroad vehicle markets. It presents a comprehensive experimental research work on aftertreatment skin temperature and the radiated impact on its neighboring parts in a nonroad vehicle powered by a middle range diesel engine under aftertreatment inlet/outlet with insulation and without insulation with multiple experimental conditions, as well as validating the emission results with these two different aftertreatment configurations. According to the experimental results, it can be observed that the aftertreatment inlet/outlet with insulation and without insulation using a Diesel Oxidant Catalyst (DOC) + Diesel Particle Filter (DPF) + Selective Catalytic Reduction (SCR) scheme could both meet China StageIV emission regulations and the whole vehicle arrangement. The connection pipe is generally short between the aftertreatment and the engine turbo charger on nonroad application vehicles, which results in the exhaust gas temperature of the internal aftertreatment at each point being similar, with variation within ±2% for the aftertreatment inlet/outlet with insulation compared to the aftertreatment inlet/outlet without insulation. The aftertreatment skin temperature differences under these two configurations occur on the inlet module and outlet module, and the skin temperatures of other aftertreatment modules are little impacted. These experimental results also validate the radiation model. All aftertreatment skin temperatures are measured with different experimental conditions. In future, if considering integrating other parts like sensors on the surface of the aftertreatment, the configuration with insulation is recommended. As per the experimental results, the maximum inlet skin temperature can lower nearly 50% with insulation and the maximum outlet temperature could lower about 28% compared to the configuration without inlet/outlet insulation. If taking cost into consideration, the configuration without insulation is suggested. This research also introduces alternative solutions for different concerns for real applications. The methodology provides effective guidance and reference for future aftertreatment insulation considerations for inlet modules and outlet modules on real applications.

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Turbine and exhaust ports thermal insulation impact on the engine efficiency and aftertreatment inlet temperature

Cited by 27 publications

References 40 publications

Efficient light-duty engine using turbulent jet ignition of lean methane mixtures

Efficient light-duty engine using turbulent jet ignition of lean methane mixtures

Late Fuel Post-Injection Influence on the Dynamics and Efficiency of Wall-Flow Particulate Filters Regeneration

Research on Aftertreatment Inlet_Outlet Insulation for A Nonroad Middle Range Diesel Engine

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