Implementation of a 0-D/1-D/3-D Process for the Heat Release Prediction of a Gasoline Engine in the Early Development Stage

Rota, Christian; Mustafa, Kenan; Winder, Nicholas; Osborne, Richard; Morgan, Rod; Mason, David; Heikal, Morgan

doi:10.4271/2019-01-0468

Cited by 2 publications

(39 citation statements)

References 35 publications

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“…Therefore, when the k/ε ratios are lower than the threshold value set by CTSB, the limiter has no effect on the calculation results. A more detailed explanation of the TSB can be found in [10,33,100]. A value corresponding to 0.346 was used during this research.…”

Section: Turbulence Modelling Within the Rans Cfd Frameworkmentioning

confidence: 99%

“…The effect of different engine speeds on the turbulent mixing time is shown inFigure 44. Higher engine speeds correspond to lower τt's magnitudes, which result in faster engine combustion rates[100]. The turbulent mixing time's shape at 5500rpm, against the crank angle, compared to the lower engine speed, does not show the sudden drop close to IVC timing.…”

mentioning

confidence: 92%

“…Moreover, comparing cases with similar B/S ratios (e.g Case 2 and Case5) shows that more compact engine variant result in lower in-cylinder turbulence during combustion, thus, higher τSRM profile. Thus, improvedengine knock tolerance, compared to cases with bigger bore would be predicted by the SRM[19,100].…”

mentioning

confidence: 98%

“…, the turbulent mixing time profiles, derived from CFD calculations, will result in higher engine knock tolerance for the engine cases with smaller bore[88,100,112]. The main objective of this analysis was to assess the capability of the turbulence scaling factor response to provide the SRM with correct input for different B/S ratios during the early screening of different combustion system configurations.…”

mentioning

confidence: 99%

“…A value of around 15% was selected as threshold value. Index values above the chosen threshold would result in abnormal combustion[100] (see Paragraph 4.3.6). The SRM ignition timing of each explored B/S ratios was initially held constant at -14 °CA ATDC(F), corresponding to the ignition timing of Case 1.…”

mentioning

confidence: 99%

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A process for an efficient heat release prediction at the concepts screening stage of gasoline engine development

Rota

Morgan

Mustafa

et al. 2020

International Journal of Engine Research

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In recent years, the exploration of new combustion technologies has accelerated in response to increasingly stringent emissions regulations and fuel economy demands. Virtual engineering tools, that enable the screening of novel hardware and engine calibrations at the early stage of engine development, have become imperative to meet new emission regulations. One-dimensional engine simulations are used at the start of the design of a new engine to define the overall combustion system geometries. Later, more complex three-dimensional computational fluid dynamics calculations are coupled to one-dimensional engine system codes to optimise initial concept geometries and define a system design ready for prototyping. To provide meaningful results, one-dimensional engine system codes often use empirical-based combustion models to calculate the engine burn rate. Moreover, realistic engine burn rates responses, for the entire engine map and for different calibrations, are required to provide three-dimensional computational fluid dynamics codes with correct boundary conditions during the design optimisation phase. Thus, the burn characteristic of new non-traditional combustion solution, for which little experimental data are available, needs to be initially assumed. To improve virtual development and reduce this uncertainty, the industry’s attention shifted towards quasi-dimensional combustion models capable of providing engine burn rate predictions. Within the quasi-dimensional modelling framework, turbulence models, adding extra user-input variables, are required to capture the effect of different combustion chamber geometries on the engine combustion rate. Rigorous validation of zero-dimensional turbulence models for different engine concepts and calibrations is therefore needed to enable quasi-dimensional combustion models to predict the engine burn rate. An alternative methodology, with limited dependency on previous test data, is required to enhance the exploration of novel combustion strategies and geometric architectures. An available process, based on a quasi-dimensional combustion stochastic reactor model, a one-dimensional engine system model and non-combusting three-dimensional computational fluid dynamics calculations, was used for this work. The approach uses limited non-combusting computational fluid dynamics calculations and a previously developed scaling factor response for the stochastic reactor model turbulence input ( τSRM) to quickly predict the engine rate of heat release. In this work, the scaling factor response was assessed against two different engine variants over a variety of engine operating conditions. Moreover, the same response was used to predict the effect of different bore-to-stroke ratios on the engine combustion rate and knock tolerance. Non-combusting computational fluid dynamics and one-dimensional engine system simulations have been carried out to investigate changes in turbulence characteristics due to different engine variants and bore-to-stroke ratios. It was shown that limited number of non-combusting computational fluid dynamics runs is required to characterise the in-cylinder turbulence for each explored engine variant. The scaling factor response was used to manipulate the turbulence input ( τSRM) resulting in good engine burn rates predictions for the explored engine variants and bore-to-stroke ratios. The presented methodology showed augmented predictive capabilities and has potential to move the engine development towards a less hardware dependent virtual approach, offering a practical solution for the exploration of new engine concepts.

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Section: Turbulence Modelling Within the Rans Cfd Frameworkmentioning

confidence: 99%

mentioning

confidence: 92%

mentioning

confidence: 98%

mentioning

confidence: 99%

mentioning

confidence: 99%

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A process for an efficient heat release prediction at the concepts screening stage of gasoline engine development

Rota

Morgan

Mustafa

et al. 2020

International Journal of Engine Research

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A Process for an Efficient Heat Release Prediction at Multiple Engine Speeds and Valve Timings in the Early Stage of Gasoline Engine Development

Rota

Morgan

Osborne

et al. 2019

SAE Technical Paper Series

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The increasing need for cleaner and more efficient combustion systems has promoted a paradigm shift in the automotive industry. Virtual hardware and engine calibration screening at the early development stage, has become the most effective way to reduce the time necessary to bring new products to market. Virtual engine development processes need to provide realistic engine combustion rate responses for the entire engine map and for different engine calibrations. Quasi Dimensional (Q-D) combustion models have increasingly been used to predict engine performance at multiple operating conditions. The physics-based Q-D turbulence models necessary to correctly model the engine combustion rate within the Q-D combustion model framework are a computationally efficient means of capturing the effect of port and combustion chamber geometry on performance. A rigorous method of correlating the effect of air motion on combustion parameters such as heat release is required to enable novel geometric architectures to be assessed to deliver future improvements in engine performance.A previously assessed process using a combination of a 0-D combustion Stochastic Reactor Model (SRM), provided by LOGESoft, a 1-D engine system model and non-combusting, 'cold' CFD is used. The approach uses a single baseline CFD run and a user developed scalar mixing time (τSRM) response to quickly predict the Rate of Heat Release (RoHR). In this work, the physically-based response for τSRM has been further developed to consider the effect of Variable Valve Timing (VVT) for a variety of engine operating conditions. Cold CFD and 1-D engine simulations have initially been carried out to investigate changes in Turbulent Kinetic Energy (k) and its dissipation (ε) caused by VVT changes, allowing the engine Rate of Heat Release (RoHR) to be predicted. The change in the intake flow velocity was correlated to the scalar mixing time, τSRM resulting in a good engine RoHR prediction at the explored conditions.

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Implementation of a 0-D/1-D/3-D Process for the Heat Release Prediction of a Gasoline Engine in the Early Development Stage

Cited by 2 publications

References 35 publications

A process for an efficient heat release prediction at the concepts screening stage of gasoline engine development

A process for an efficient heat release prediction at the concepts screening stage of gasoline engine development

A Process for an Efficient Heat Release Prediction at Multiple Engine Speeds and Valve Timings in the Early Stage of Gasoline Engine Development

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