The Future Heavy-duty Engine -  Basic Engine Concept for Maximum CO2 Reduction

Horvath, Andreas; Seitz, Hans Felix; Gelter, Juergen; Raser, Bernhard

doi:10.1007/s38313-020-0276-9

Cited by 4 publications

(1 citation statement)

References 5 publications

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“…In combination with a highly efficient turbo-charging system and increased boost pressure, the Miller cycle improves efficiency over a wide load range without increasing soot emissions. 9,10 In addition, the Miller cycle also lowers engine-out NOx emissions, 2,5,9,11 which positively affect the inherent efficiency-NOx trade-off of CI engines. Third, more recent publications focus on the interaction of a CI engine with a VVT and its exhaust aftertreatment system (ATS).…”

Section: Introductionmentioning

confidence: 99%

A method to quantify the advantages of a variable valve train for CI engines

Moretto,

Hänggi,

Omanovic

et al. 2023

International Journal of Engine Research

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Today’s CI engines are subject to strict regulations of pollutant emissions and ambitious fuel consumption targets. Therefore, the interaction between the engine and the exhaust aftertreatment system (ATS) has become increasingly important. Numerous studies have shown that a variable valve train (VVT) improves the interaction between engine and ATS. However, most of these studies either quantify the advantage on a specific engine or only present complex CFD models, such that the results are not easily transferable to different engines. Thus, engine manufacturers cannot directly use these results to assess the advantage of various VVT strategies for their engines. In this paper, we propose a cycle-discrete cylinder model based on first principles which allows to simulate various VVT strategies. In contrast to present methods based on CFD, the proposed cylinder model can be realized with the equations presented. Furthermore, the model is identified with measurement data of an engine without a VVT. A separate engine, which is retrofitted with a fully VVT, is used to validate the proposed modeling approach. Using the identified model in combination with a mean-value model of the air path, we are able to simulate the effects of early intake valve closing, early exhaust valve opening, and cylinder deactivation for a complete CI engine that has no VVT installed. The model is then used to highlight the advantage of a VVT for two scenarios at part-load operation. At cold start, where the temperature of the ATS must be increased quickly, variable valve timing achieves higher enthalpy flows to the ATS while also lowering engine-out NOx emissions when compared to a standard engine strategy. If the ATS is at the operating temperature, cylinder deactivation achieves significantly higher enthalpy flows which prevents the ATS from cooling down. In addition, cylinder deactivation also lowers fuel consumption and engine-out NOx emissions.

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Section: Introductionmentioning

confidence: 99%

A method to quantify the advantages of a variable valve train for CI engines

Moretto,

Hänggi,

Omanovic

et al. 2023

International Journal of Engine Research

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Future Sustainable Transport Fuels for Indian Heavy Duty Vehicles

Dev

2022

Energy, Environment, and Sustainability

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Effects of Multiple Injection Strategies on Heavy-Duty Diesel Energy Distributions and Emissions Under High Peak Combustion Pressures

et al. 2022

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Peak combustion pressures (PCP) are increased in heavy-duty diesel engines to obtain higher thermal efficiency. Fuel injection strategy has been a major measure to improve the combustion and emissions of diesel engines. But most existing work of multi-injection strategies was not limited by PCP or was conducted under lower PCP (∼15 MPa). In this study, an experimental study is conducted to further improve the understanding of injection strategies on engine performance under a relative higher peak combustion pressure at 20 MPa. The four tested injection strategies are single main injection, pilot-main injection, main-post injection, and pilot-main-post injection. The effects of PCP on brake thermal efficiency (BTE) and other engine performances are also investigated under the same NOx emissions conditions. Results indicate that more advanced injection timing can obtain higher BTE, while the injection pressure has less effects on BTE as it is higher than 120 MPa. For double-injection, the smaller interval on pilot-main or main-post and the less pilot or post mass improves BTE and emissions. The PCPs are linearly correlated to the BTE, peak average temperature, and peak pressure rise rate (PRR), and the increment of BTE, peak average temperature, and peak PRR are about 0.3%, 30 K, and 0.1 MPa/CA for every 1 MPa increase in PCP, respectively. This also means that the improvement on BTE by the increase of PCP imparts greater thermal and mechanical loads on engine materials and components. At 20 MPa PCP, based on the optimized injection strategies, the BTE of all four strategies is about 42.8%, and the peak PRR of all four strategies is about 0.8 MPa/CA. At a given NOx emission of 17.4 g/kWh and approximate 20 MPa PCP, all four injection strategies have minor effects on distribution of fuel energy and emissions. Therefore, it can be concluded that the injection strategies have fewer effects on BTE and emissions at the higher peak combustion pressure of 20 MPa; the main purpose of injection strategies is to reduce the peak PRR or reach the potentially required temperature for aftertreatment devices.

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The Future Heavy-duty Engine - Basic Engine Concept for Maximum CO2 Reduction

Cited by 4 publications

References 5 publications

A method to quantify the advantages of a variable valve train for CI engines

A method to quantify the advantages of a variable valve train for CI engines

Future Sustainable Transport Fuels for Indian Heavy Duty Vehicles

Effects of Multiple Injection Strategies on Heavy-Duty Diesel Energy Distributions and Emissions Under High Peak Combustion Pressures

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