1D Engine Simulation Approach for Optimizing Engine and Exhaust Aftertreatment Thermal Management for Passenger Car Diesel Engines by Means of Variable Valve Train (VVT) Applications

Deppenkemper, Kai; Özyalcin, Ibrahim Can; Ehrly, Markus; Pischinger, Stefan; Bergmann, Dirk; Schönen, Markus

doi:10.4271/2018-01-0163

Cited by 12 publications

(8 citation statements)

References 3 publications

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“…Recent studies carried out by Deppenkemper et al 7 found that in an engine with similar specifications, the light-off temperature of the DOC is around 200 °C according to an averaged space velocity of 57,700 L/h during the WLTC. 7 Other authors like Guardiola et al 29 take this temperature as a reference for the DOC light-off temperature. In order to evaluate the temperature downstream the DOC, a catalyst model 25 has been included into the engine model.…”

Section: Resultsmentioning

confidence: 99%

“…6 Delaying the IVO event reduces valve overlap, leading to a very low or insignificant backflow into intake manifold. Deppenkemper et al 7 found, using a one-dimensional (1D) engine model, that if the IVO is delayed up to the beginning of the intake stroke, the velocity at which the air enters into the cylinder will be higher due to the lower pressure inside the cylinder. This increase in inlet air velocity enhances in-cylinder turbulence, which improves the mixing process, resulting in lower HC emissions.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Resultsmentioning

confidence: 99%

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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“…Delaying the IVO (LIVO) event reduces valve overlap, leading to a very low or insignificant backflow into intake manifold. Deppenkemper et al [9] found, using a one-dimensional engine model, that if the IVO is delayed up to the beginning of the intake stroke, the velocity at which the air enters into the cylinder will be higher due to the lower pressure inside the cylinder. This increase in inlet air velocity enhances in-cylinder turbulence, which improves the mixing process, which results in lower HC emissions.…”

Section: Intake Valve Opening (Ivo)mentioning

confidence: 99%

“…The faster the light-off temperature (defined as the temperature at which the conversion efficiency reaches 50%) in the catalyst is reached, the faster the efficient oxidation of CO and HC, and the oxidation of NO to NO 2 , is achieved. This light-off temperature is considered to be around 200 • C according to an averaged space velocity of 57,700 L/h during the WLTC [9,31]. The decrease in DOC-out NO 2 may have a negative effect on downstream NO x abatement, specially at temperatures below 250 • C, such as those at engine start up [32].…”

Section: Model Validation At Transient Operating Conditionsmentioning

confidence: 99%

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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“…Kai D. et al tested several VVT variants (exhaust cam phasing, late intake valve opening, Miller, second exhaust event, cylinder deactivation) as promising heating strategies. These heating strategies are finally compared to conventional heating measures to demonstrate their potentials in terms of faster after-treatment light-off with increased conversion efficiencies and benefits in CO 2 emissions [10].…”

Section: Introductionmentioning

confidence: 99%

Investigation on the Effects of Internal EGR by Variable Exhaust Valve Actuation with Post Injection on Auto-ignited Combustion and Emission Performance

Cho

Lee

2018

Applied Sciences

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Variable valve mechanisms are usually applied to a gasoline combustion engine to improve its power performance by controlling the amount of intake air according to the operating load. These mechanisms offer one possibility of resolving the conflict of objectives between a further reduction of raw emissions and an improvement in fuel efficiency. In recent years, variable valve control systems have become extremely important in the diesel combustion engine. Importantly, it has been shown that there are several potential benefits of applying variable valve timing (VVT) to a compression ignition engine. Valve train variability could offer one option to achieve the reduction goals of engine-out emissions and fuel consumption. The aim of this study was to investigate the effects on part load combustion and emission performance of internal exhaust gas recirculation (EGR) by variable exhaust valve lift actuation using a cam-in-cam system, which is an electronically variable valve device with a variable inside cam retarded to about 30 degrees. Numerical simulation based on GT-POWER has been performed to predict the NO x reduction strategy at the part load operating point of 1200 rpm in a four-valve diesel engine. A GT-POWER model of a common-rail direct injection engine with internal EGR was built and verified with experimental data. As a result, large potential for reducing NO x emissions through the use of exhaust valve control has been identified. Namely, it is possible to utilize heat efficiently as recompression of retarded post injection with downscaled specification of the exhaust valve rather than the intake valve, even if the CIC V1 condition with a reduction of the exhaust valve has a higher internal EGR rate of about 2% compared to that of the CIC V2 condition.

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1D Engine Simulation Approach for Optimizing Engine and Exhaust Aftertreatment Thermal Management for Passenger Car Diesel Engines by Means of Variable Valve Train (VVT) Applications

Cited by 12 publications

References 3 publications

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

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

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

Investigation on the Effects of Internal EGR by Variable Exhaust Valve Actuation with Post Injection on Auto-ignited Combustion and Emission Performance

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