Study on transient emission spikes reduction of a heavy-duty diesel engine equipped with a variable intake valve closing timing mechanism and a two-stage turbocharger

Zhou, Xiaobo; Liu, Erxi; Sun, Dezeng; Su, Weifeng

doi:10.1177/1468087417748837

Cited by 13 publications

(8 citation statements)

References 34 publications

(49 reference statements)

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“…The combination of EGR and LIVC helped to improve the NO x -soot trade-off relation [13,14]. Similarly, Zhou et al [17] achieved a reduction in particle matter emissions by 32.9%, with a small increase in NO x by applying LIVC strategy and an optimal control of the VGT (Variable Geometry Turbine) and EGR during realistic transient conditions.…”

Section: Intake Valve Closing (Ivc)mentioning

confidence: 90%

Development of a Variable Valve Actuation Control to Improve Diesel Oxidation Catalyst Efficiency and Emissions in a Light Duty Diesel Engine

et al. 2020

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Growing interest has arisen to adopt Variable Valve Timing (VVT) technology for automotive engines due to the need to fulfill the pollutant emission regulations. Several VVT strategies, such as the exhaust re-opening and the late exhaust closing, can be used to achieve an increment in the after-treatment upstream temperature by increasing the residual gas amount. In this study, a one-dimensional gas dynamics engine model has been used to simulate several VVT strategies and develop a control system to actuate over the valves timing in order to increase diesel oxidation catalyst efficiency and reduce the exhaust pollutant emissions. A transient operating conditions comparison, taking the Worldwide Harmonized Light-Duty Vehicles Test Cycle (WLTC) as a reference, has been done by analyzing fuel economy, HC and CO pollutant emissions levels. The results conclude that the combination of an early exhaust and a late intake valve events leads to a 20% reduction in CO emissions with a fuel penalty of 6% over the low speed stage of the WLTC, during the warm-up of the oxidation catalyst. The same set-up is able to reduce HC emissions down to 16% and NOx emission by 13%.

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Section: Intake Valve Closing (Ivc)mentioning

confidence: 90%

Development of a Variable Valve Actuation Control to Improve Diesel Oxidation Catalyst Efficiency and Emissions in a Light Duty Diesel Engine

et al. 2020

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“…The combination of EGR and LIVC helped to improve the NO x -soot trade-off relation. 10,11 Similarly, Zhou et al 14 achieved a reduction in particle matter emissions by 32.9% with a small increase in NO x by applying LIVC strategy and an optimal control of the variable geometry turbine (VGT) and EGR during realistic transient conditions.…”

Section: Introductionmentioning

confidence: 99%

Diesel engine optimization and exhaust thermal management by means of variable valve train strategies

Arnau

Martín

Plá

et al. 2020

International Journal of Engine Research

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Due to the need to achieve a fast warm-up of the after-treatment system in order to fulfill the pollutant emission regulations, a growing interest has arisen to adopt variable valve timing technology for automotive engines. Several variable valve timing strategies can be used to achieve an increment in the after-treatment upstream temperature by increasing the residual gas amount. In this study, a one-dimensional gas dynamics engine model has been used to carry out a simulation study comparing several exhaust variable valve actuation strategies. A steady-state analysis has been done in order to evaluate the potential of the different strategies at different operating points. Finally, the effect on the after-treatment warm-up, fuel economy and pollutant emission levels was evaluated over the worldwide harmonized light vehicles test cycle. As a conclusion, the combination of an advanced exhaust (early exhaust valve opening and early exhaust valve closing) and a delayed intake (late intake valve opening and late intake valve closing) presented the best trade-off between exhaust temperature increment and fuel consumption, which achieved a mean temperature increment during low-speed phase of the worldwide harmonized light vehicles test cycle of 27 °C with a fuel penalty of 6%. The exhaust valve re-opening technique offers a worse trade-off. However, the exhaust valve re-opening leads to lower nitrogen oxide (29% less) and carbon monoxide (11% less) pollutant emissions.

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“…Still, despite their advantages, Diesel engines are one of the major atmospheric pollutant contributors, such as NOx and particulate matter (PM). The aforementioned concerns have motivated policy makers and engine manufacturers to introduce more rigid and strict emission regulations [2,3]; among them, water-emulsified fuels can simultaneously reduce both NOx and PM emissions [4] without increasing cost.…”

Section: Introductionmentioning

confidence: 99%

A simple model for breakup time prediction of water-heavy fuel oil emulsion droplets

Fostiropoulos

Strotos

Νikolopoulos

et al. 2021

International Journal of Heat and Mass Transfer

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Immiscible heavy fuel-water (W/HFO) emulsion droplets inside combustion chambers are subjected to explosive boiling and fragmentation due to the different boiling point between the water and the surrounding host fuel. These processes, termed as either puffing or micro-explosion, are investigated with the aid of a CFD model that solves the Navier-Stokes and energy conservation equations alongside with three sets of VoF transport equations resolving the formed interfaces. The model is applied in 2-D axisymmetric configuration and it is valid up to the time instant of HFO droplet initiation of disintegration, referred to as breakup time. Model predictions are obtained for a wide range of pressure, temperature, water droplet surface depth and Weber number; these are then used to calibrate the parameters of a fitting model estimating the initiation breakup time of the W/HFO droplet emulsion with a single embedded water droplet. The model assumes that the breakup time can be split in two distinct temporal stages. The first one is defined by the time needed for the embedded water droplet to heat up and reach a predefined superheat temperature and a vapor bubble to form; while the succeeding stage accounts for the time period of vapor bubble growth, leading eventually to emulsion droplet break up. It is found that the fitting parameters are ±10% accurate in the examined range of 𝑊𝑒 <220, 𝑇 <2000 K, 𝑃 <140 bar and 𝛿 < 0.15.

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Study on transient emission spikes reduction of a heavy-duty diesel engine equipped with a variable intake valve closing timing mechanism and a two-stage turbocharger

Cited by 13 publications

References 34 publications

Development of a Variable Valve Actuation Control to Improve Diesel Oxidation Catalyst Efficiency and Emissions in a Light Duty Diesel Engine

Development of a Variable Valve Actuation Control to Improve Diesel Oxidation Catalyst Efficiency and Emissions in a Light Duty Diesel Engine

Diesel engine optimization and exhaust thermal management by means of variable valve train strategies

A simple model for breakup time prediction of water-heavy fuel oil emulsion droplets

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