Further optimization of NOx emissions under the EU 6d regulation

Krüger, Michael; Bareiss, Stefan; Kufferath, Andreas; Naber, Dirk; Ruff, D.T.; Schumacher, H.

doi:10.1007/978-3-658-25939-6_68

Cited by 6 publications

(4 citation statements)

References 1 publication

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“…To prepare to meet future challenges, the influence of a hybrid drive system will have to be considered much more carefully, and the EAS will have to be improved still further. Primarily, this statement refers to the use of mainly passively operated LNTs with a minimum number of purges [37], since this use increases both CO 2 and CH 4 emissions. Secondarily, it also refers to, e.g., external air pumps that are used to condition the EAS before starting the engine.…”

Section: Discussionmentioning

confidence: 99%

Current experimental developments in 48 V-based CI-driven SUVs in response to expected future EU7 legislation

Kühberger

Wancura

Nenning

et al. 2021

Automot. Engine Technol.

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In this paper, we describe experimental developments in an Exhaust Aftertreatment System (EAS) used in a four-cylinder Compression Ignition (CI) engine. To meet the carbon dioxide (CO$$_\mathrm {2}$$ 2 ) fleet limit values and to demonstrate a clean emission concept, the CI engine needs to be further developed in a hybridized, modern form before it can be included in the future fleet. In this work, the existing EAS was replaced by an Electrically Heated Catalyst (EHC) and a Selective Catalytic Reduction (SCR) double-dosing system. We focused specifically on calibrating the heating modes in tandem with the electric exhaust heating, which enabled us to develop an ultra-fast light-off concept. The paper first outlines the development steps, which were subsequently validated using the Worldwide harmonized Light-duty vehicles Test Cycle (WLTC). Then, based on the defined calibration, a sensitivity analysis was conducted by performing various dynamic driving cycles. In particular, we identified emission species that may be limited in the future, such as laughing gas (N$$_\mathrm {2}$$ 2 O), ammonia (NH$$_\mathrm {3}$$ 3 ), or formaldehyde (HCHO), and examined the effects of a general, additional decrease in the limit values, which may occur in the near future. This advanced emission concept can be applied when considering overall internal engine and external exhaust system measures. In our study, we demonstrate impressively low tailpipe (TP) emissions, but also clarify the system limits and the necessary framework conditions that ensure the applicability of this drivetrain concept in this sector.

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Section: Discussionmentioning

confidence: 99%

Current experimental developments in 48 V-based CI-driven SUVs in response to expected future EU7 legislation

Kühberger

Wancura

Nenning

et al. 2021

Automot. Engine Technol.

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“…17,28 Further, the use of variable geometry turbochargers is also found to be helpful to increase the exhaust gas enthalpy during cold start. 29 It is worthwhile to mention that for the upcoming very stringent heavy-duty NO x emission regulation, the aftertreatment device conversion efficiency has to be greater than 97 and 99.3%, respectively, to achieve 0.02 g/bhp-h NO x levels during the cold and hot portions of the FTP cycle even after reducing engine-out NO x . 30 The greater challenge here is that the NO x must fall below stricter emission standards, along with higher engine efficiency.…”

Section: Conventional Combustion Limitations and Solutionsmentioning

confidence: 99%

“…49 The various technologies that can be explored include SCR systems with advanced low temperature conversion, 17,233 advanced urea dosing at low temperatures via gaseous ammonia dosing, heating the dosing nozzle to assist in rapid atomization and improved traps for NO x to address cold start emissions. 17 The engine hardware measures that can be explored to increase exhaust gas enthalpy include variable geometry turbochargers 29 and dynamic cylinder deactivation. 28…”

Section: Directions For Future Workmentioning

confidence: 99%

Prospective fuels for diesel low temperature combustion engine applications: A critical review

Krishnasamy

Gupta

Reitz

2020

International Journal of Engine Research

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Low Temperature Combustion (LTC) strategies are most promising to simultaneously reduce oxides of nitrogen (NOx) and soot emissions from diesel engines along with offering higher thermal efficiency. Commercial wide spread implementation of diesel LTC strategies requires several challenges to be addressed, including lack of precise ignition timing control, widening the narrow operating load ranges and reducing high unburned fuel emissions. These challenges can be addressed through modifications in the engine or fuel design or both. The timing and rate of combustion in several LTC strategies are controlled primarily by the chemical kinetics of the fuel. Since, diesel fuel reactivity and volatility are tailor-made to perform well under conventional diesel combustion conditions, its application in LTC poses several problems, as highlighted in this paper. Hence, it is important to identify suitable alternative fuels for the different diesel LTC strategies. The published literature on LTC over the past 25 years is critically analyzed to discuss the evolution of the different diesel LTC strategies, their operability limits, the challenges and the controlling parameters for each strategy. This is followed by in-depth analysis of the role of the fuel and the fuel requirements for each strategy. Further, the importance of adopting a hybrid surrogate modeling approach to enable numerical simulation of diesel LTC is highlighted. A novel attempt of relating various diesel low temperature combustion (LTC) strategies based on the approach followed to achieve positive ignition dwell through different injection strategies, utilizing high exhaust gas recirculation (EGR), and dual fuels is presented. The need for replacing diesel with alternative liquid fuels in LTC strategies is presented by highlighting the fundamental problems associated with diesel fuel characteristics. The review concludes by suggesting potential alternative fuels for various diesel LTC strategies and provides directions for future work to address the challenges facing compression ignition LTC operation.

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“…The ICE we use for our investigations serves as a platform for research purposes at Robert Bosch GmbH [42]. The test subject is an inline four-cylinder light-duty diesel engine for passenger cars that is equipped with a direct injection system.…”

Section: Test Subjectmentioning

confidence: 99%

A stochastic design optimization methodology to reduce emission spread in combustion engines

Mourat

Eckstein

Koch

2020

Automot. Engine Technol.

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This paper introduces a method for efficiently solving stochastic optimization problems in the field of engine calibration. The main objective is to make more conscious decisions during the base engine calibration process by considering the system uncertainty due to component tolerances and thus enabling more robust design, low emissions, and avoiding expensive recalibration steps that generate costs and possibly postpone the start of production. The main idea behind the approach is to optimize the design parameters of the engine control unit (ECU) that are subject to uncertainty by considering the resulting output uncertainty. The premise is that a model of the system under study exists, which can be evaluated cheaply, and the system tolerance is known. Furthermore, it is essential that the stochastic optimization problem can be formulated such that the objective function and the constraint functions can be expressed using proper metrics such as the value at risk (VaR). The main idea is to derive analytically closed formulations for the VaR, which are cheap to evaluate and thus reduce the computational effort of evaluating the objective and constraints. The VaR is therefore learned as a function of the input parameters of the initial model using a supervised learning algorithm. For this work, we employ Gaussian process regression models. To illustrate the benefits of the approach, it is applied to a representative engine calibration problem. The results show a significant improvement in emissions compared to the deterministic setting, where the optimization problem is constructed using safety coefficients. We also show that the computation time is comparable to the deterministic setting and is orders of magnitude less than solving the problem using the Monte-Carlo or quasi-Monte-Carlo method.

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Further optimization of NOx emissions under the EU 6d regulation

Cited by 6 publications

References 1 publication

Current experimental developments in 48 V-based CI-driven SUVs in response to expected future EU7 legislation

Current experimental developments in 48 V-based CI-driven SUVs in response to expected future EU7 legislation

Prospective fuels for diesel low temperature combustion engine applications: A critical review

A stochastic design optimization methodology to reduce emission spread in combustion engines

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