A Methodology to Mimic Cycle to Cycle Variations and to Predict Knock Occurrence through Numerical Simulation

Millo, Federico; Rolando, Luciano; Pautasso, E.; Servetto, Emanuele

doi:10.4271/2014-01-1070

Cited by 20 publications

(14 citation statements)

References 19 publications

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“…The co-simulation includes dSPACE Automotive Simulation Models (ASM) for driver and vehicle dynamics, a SimulationX transmission model, a GT-POWER internal combustion engine model, and a MATLAB Simulink power net model. 10…”

Section: System Overviewmentioning

confidence: 99%

Electric torque assist and supercharging of a downsized gasoline engine in a 48V mild hybrid powertrain

Xia

Griefnow

Tidau

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part D:

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48V systems enable not only mild hybrid functionalities such as recuperation or torque assist by a belt-driven starter generator (BSG), but also electrification of accessories and the engine boosting system. To maximize the powertrain efficiency, a proper layout of the electrified system and an optimized distribution of the electric power during transient operation is essential. In this study, a vehicle co-simulation of a conventional powertrain with a downsized turbocharged gasoline engine is extended by a 48V system with an electric compressor (eC) and a BSG. The control functions of the eC and BSG are based on a state-of-the-art vehicle application and calibrated for transient operating conditions. The engine model, which is built using a one-dimensional crank angle resolved approach in GT-POWER, has been validated with measurement data and is used to predict the interaction between the eC and the engine air path. The investigations using the simulation platform show that the 48V eC and the BSG can significantly improve the fuel effïciency if the electric energy consumption is initially neglected. However, when considering the electric energy consumption within the vehicle co-simulation, efficient operation is particularly depending on driver torque demand, the battery state-of-charge and charging effïciency. Hence, intelligent operating strategies are necessary to take advantage of the better torque response and improve fuel consumption at the same time.

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Section: System Overviewmentioning

confidence: 99%

Electric torque assist and supercharging of a downsized gasoline engine in a 48V mild hybrid powertrain

Xia

Griefnow

Tidau

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part D:

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“…When modeling the cyclic varied in-cylinder combustion, a functional description ranging from determinism to randomness is needed [13]. The Wiebe function, a frequently used equation, is chosen to simulate combustion [17].…”

Section: B Combustion Modelmentioning

confidence: 99%

“…For example, a statistical analysis of the cyclic combustion event is explained from view of physics [11], and experimental analyses on cyclic variation have also been provided [12]. In addition, attempts at modeling the cyclic transient in the cylinder state have been proposed in [13], which focus on the cyclic variation influence of the residual gas fraction.…”

Section: Introductionmentioning

confidence: 99%

Simulation of knock probability in an internal combustion engine

Shen

2018

Phys. Rev. E

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In spark-ignition internal combustion engines, fluctuations of the in-cylinder pressure trace and the tendency of combustion knock are usually different from one cycle to another. These cycle-to-cycle variations are affected by the initial state at ignition time and the subsequent burning. The occurrence of the phenomena is unpredictable, and their stochastic nature offers challenges in the optimization of engine control strategies. In this paper, a simulator providing a series of cycle-to-cycle varied in-cylinder pressures is introduced. The Wiebe function and Livengood-Wu integration are used to describe the determinacy of combustion. Various means, including the Markov chain, are introduced to express the stochastic quantities during combustion. In addition, the combustion of a given knock probability is simulated.

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“…BSG: Belt Starter Generator; eSC: electric SuperCharger. The maximum T3 was increased from 930 • C to 980 • C, assuming the adoption of an enhanced turbocharger system capable to withstand to exhaust gas temperatures up to 980 • C. Furthermore, a refined knock control, capable of fully exploiting the engine torque potential until the knock limited spark advance was also adopted, as reported by Millo et al[28].3.ST-MHEV: an electrified powertrain concept (P0 architecture), featuring the same Lambda-1 engine presented in 2 (1.4 L Stoich.) and integrating a 48 V BSG.…”

mentioning

confidence: 99%

“…The ECMS defines the optimum powersplit at each time step by minimizing an instantaneous cost function. As described by Millo et al [28], an equivalent fuel consumption can be associated with the use of electrical energy: under the hypothesis of charge sustaining condition, this fuel consumption is equivalent to the fuel flow required by the ICE to re-establish the battery SoC at the previous level. The battery equivalent fuel As far as the EMS is concerned, in this work the Equivalent Consumption Minimization Strategy (ECMS) [25] technique was adopted.…”

mentioning

confidence: 99%

Numerical Investigation of 48 V Electrification Potential in Terms of Fuel Economy and Vehicle Performance for a Lambda-1 Gasoline Passenger Car

et al. 2019

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Real Driving Emissions (RDE) regulations require the adoption of stoichiometric operation across the entire engine map for downsized turbocharged gasoline engines, which have been so far generally exploiting spark timing retard and mixture enrichment for knock mitigation. However, stoichiometric operation has a detrimental effect on engine and vehicle performances if no countermeasures are taken, such as alternative approaches for knock mitigation, as the exploitation of Miller cycle and/or powertrain electrification to improve vehicle acceleration performance. This research activity aims, therefore, to assess the potential of 48 V electrification and of the adoption of Miller cycle for a downsized and stoichiometric turbocharged gasoline engine. An integrated vehicle and powertrain model was developed for a reference passenger car, equipped with a EU5 gasoline turbocharged engine. Afterwards, two different 48 V electrified powertrain concepts, one featuring a Belt Starter Generator (BSG) mild-hybrid architecture, the other featuring, in addition to the BSG, a Miller cycle engine combined with an e-supercharger were developed and investigated. Vehicle performances were evaluated both in terms of elasticity maneuvers and of CO 2 emissions for type approval and RDE driving cycles. Numerical simulations highlighted potential improvements up to 16% CO 2 reduction on RDE driving cycle of a 48 V electrified vehicle featuring a high efficiency powertrain with respect to a EU5 engine and more than 10% of transient performance improvement.Energies 2019, 12, 2998 2 of 21 gases at a higher level, eliciting a further enrichment of the mixture. What is more, the use of mixture enrichment (i.e., moving from a stoichiometric to rich combustion) while cooling the in-cylinder charge and the exhaust gases, increases the CO emissions during high engine load operation, as highlighted by Clairotte et al. [3]. Moreover, future Regulation may prescribe a conformity factor for CO [4] limiting the exploitation of the fuel enrichment and pushing the development of the gasoline engines towards stoichiometric operation [5,6]. This aim can be achieved with the adoption of different powertrain technologies, like cooled exhaust manifold, high temperature resistant turbine as well as water injection, Miller cycle and advanced turbocharging, as explained by Glahn et al. [6].On the other hand, concerning the greenhouse emissions, the average fleet target value for CO 2 has been set to be 95 g/km from 2021 [7], measured according to the new Worldwide Harmonized Light-Duty Vehicles Test Procedure (WLTP) and correlated to the value of the New European Driving Cycle (NEDC). Moreover, recently the European Parliament and the Council adopted Regulation (EU) 2019/631 [8] setting CO 2 emission performance standards for new passenger cars in the EU for the

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A Methodology to Mimic Cycle to Cycle Variations and to Predict Knock Occurrence through Numerical Simulation

Cited by 20 publications

References 19 publications

Electric torque assist and supercharging of a downsized gasoline engine in a 48V mild hybrid powertrain

Electric torque assist and supercharging of a downsized gasoline engine in a 48V mild hybrid powertrain

Simulation of knock probability in an internal combustion engine

Numerical Investigation of 48 V Electrification Potential in Terms of Fuel Economy and Vehicle Performance for a Lambda-1 Gasoline Passenger Car

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