Diesel Starting: A Mathematical Model

Gardner, Timothy; Henein, Naeim A.

doi:10.4271/880426

Cited by 27 publications

(14 citation statements)

References 25 publications

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“…Friction modeling in transient simulation codes has, almost, always in the past (with a few notable exceptions [13][14][15][16][17][18]) been applied in the form of mean fmep relations, remaining constant for every degree crank angle in each cycle in the model simulation; thus, the effect of real friction torque on the model's predictive capabilities was limited. This is primarily attributed to the scarcity-complexity of detailed, per degree crank angle, friction simulations.…”

Section: Introductionmentioning

confidence: 99%

“…He also proposed application of the mean fmep equation at each computational step rather than each cycle. Gardner and Henein [15], as regards engine starting, and Tuccilo et al [16] gave some preliminary transient results adopting the semi-empirical RezekaHenein [19] friction model. Ciulli et al [18] developed 3 friction models of various complexity and incorporated them in a simplified dynamic simulation.…”

Section: Introductionmentioning

confidence: 99%

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Evaluation of Various Dynamic Issues During Transient Operation of Turbocharged Diesel Engine with Special Reference to Friction Development

Rakopoulos¹,

Giakoumis²,

Dimaratos³

2007

SAE Technical Paper Series

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The modeling of transient turbocharged diesel engine operation appeared in the early seventies and continues to be in the focal point of research, due to the importance of transient response in the everyday operating conditions of engines. The majority of research has focused so far on issues concerning thermodynamic modeling, as these directly affect heat release predictions and consequently performance and pollutants emissions. On the other hand, issues concerning the dynamics of transient operation are often disregarded or over-simplified, possibly for the sake of speeding up program execution time. In the present work, an experimentally validated transient diesel engine simulation code is used to study and evaluate the importance of such dynamic issues. First of all, the development of various forces (piston, connecting rod, crank and main crankshaft bearings) is computed and illustrated in order to evaluate the importance of abrupt load increases on the bearings durability. The usual approximation of the connecting rod being considered as equivalent to two masses (one reciprocating with the piston and the other rotating with the crank) is put into test. The same holds true for another usual assumption, i.e. the crankshaft being considered as sufficiently rigid. In this work, the engine crankshaft is analyzed in detail with the instantaneous torsional angle between engine and load taken into account. Thus, details are provided concerning the development of crankshaft torsional deformation during transients. The main part of the paper focuses on the development and contribution of various friction components during turbocharged diesel engine transients. This is accomplished via the use of a recently proposed detailed friction model. Mean fmep (friction mean effective pressure) modeling is found to considerably underestimate actual friction around firing TDC, leading to lower speed droops for abrupt load increases. The piston rings assembly contribution is dominant for the particular engine, due to its high number of piston rings and its relatively low crankshaft speed. The model can be used to investigate such interesting cases as the effect of engine oil temperature on engine transient response, or the variation of oil film thickness during a cycle or a transient event.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Evaluation of Various Dynamic Issues During Transient Operation of Turbocharged Diesel Engine with Special Reference to Friction Development

Rakopoulos¹,

Giakoumis²,

Dimaratos³

2007

SAE Technical Paper Series

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“…They advanced to filling and emptying modeling [3,28], while investigating also the fundamental aspect of combustion and friction deterioration during transients [12]. Professor Henein's research group at the Wayne State University pioneered in the late eighties the study concerning engine starting based on phenomenological in-cylinder modeling [29,30]. Later, they included detailed fuel droplets and film evaporation sub-models [31,32].…”

Section: Historical Overviewmentioning

confidence: 99%

“…With the notable exceptions from only five research groups [29,30,[39][40][41]44,45,69,88,146], friction modeling in transient simulation codes has always, in the past, been used in the form of 'mean fmep' relations, remaining constant for every degree crank angle in each cycle in the model simulation. This may be attributed to the fact that friction does not affect the heat release rate (and thus the interior engine 'indicating' properties and exhaust emissions) but only the crankshaft energy balance; the latter one being, nonetheless, essential for correct transient predictions.…”

Section: Frictionmentioning

confidence: 99%

“…This may be attributed to the fact that friction does not affect the heat release rate (and thus the interior engine 'indicating' properties and exhaust emissions) but only the crankshaft energy balance; the latter one being, nonetheless, essential for correct transient predictions. Detailed friction (as well as blow-by) simulations are met in starting models [29,30], as these losses are particularly pronounced during cold start engine conditions.…”

Section: Frictionmentioning

confidence: 99%

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Review of Thermodynamic Diesel Engine Simulations under Transient Operating Conditions

Rakopoulos¹,

Giakoumis²

2006

SAE Technical Paper Series

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Study and modeling of transient operation is an important scientific objective. This is due to the fact that the majority of daily vehicle driving conditions involve transient operation, with non-linear situations experienced during engine transients. Thus, proper interconnection is needed between engine, governor, fuel pump, turbocharger and load. This paper surveys the publications available in the open literature concerning diesel engine simulations under transient operating conditions. Only those models that include both full engine thermodynamic calculations and dynamic powertrain modeling are taken into account, excluding those that focus on control design and optimization. Most of the attention is concentrated to the simulations that follow the filling and emptying modeling approach. A historical overview is given covering, in more detail, research groups with continuous and consistent study of transient operation. One of the main purposes of this paper is to summarize basic equations and modeling aspects concerning in-cylinder calculations, friction, turbocharger, engine dynamics, governor, fuel pump operation, and exhaust emissions during transients. The various limitations of the models are discussed together with the main aspects of transient operation (e.g. turbocharger lag, combustion and friction deterioration), which diversify it from the steady-state. Some of the most important findings in the field during the last 30 years are presented and discussed. The survey extends to special cases of transient diesel engine simulation, such as second-law analysis, response when the turbocharger compressor experiences surge, and whole vehicle performance. Several methods of improving transient response are also mentioned, based on the various simulations. An easy-to-read tabulation of all research groups dealing with the subject, that includes details about each model developed and engines/parameters studied, is also provided at the end of the paper.

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Diesel Starting: A Mathematical Model

Cited by 27 publications

References 25 publications

Evaluation of Various Dynamic Issues During Transient Operation of Turbocharged Diesel Engine with Special Reference to Friction Development

Evaluation of Various Dynamic Issues During Transient Operation of Turbocharged Diesel Engine with Special Reference to Friction Development

Review of Thermodynamic Diesel Engine Simulations under Transient Operating Conditions

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