Systematic Investigation of a Large Two-Stroke Engine Crankshaft Dynamics Model

Tsitsilonis, Konstantinos-Marios; Theotokatos, Gerasimos; Xiros, Nikolaos I.; Habens, Malcolm

doi:10.3390/en13102486

Cited by 8 publications

(12 citation statements)

References 45 publications

(90 reference statements)

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“…The vibration of the crankshaft [44,45] during the measurement was not analyzed as the conditions are quasi-static. Due to the character of reaction forces, we did not discuss either any vibration model or any issues of structural dynamics of reciprocating engines [46][47][48][49][50]. The entire adjustment process is controlled by a computer-based monitoring application.…”

Section: Crankshaft Geometry Measuring Methodsmentioning

confidence: 99%

Method to Increase the Accuracy of Large Crankshaft Geometry Measurements Using Counterweights to Minimize Elastic Deformations

et al. 2020

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Large crankshafts are highly susceptible to flexural deformation that causes them to undergo elastic deformation as they revolve, resulting in incorrect geometric measurements. Additional structural elements (counterweights) are used to stabilize the forces at the supports that fix the shaft during measurements. This article describes the use of temporary counterweights during measurements and presents the specifications of the measurement system and method. The effect of the proposed solution on the elastic deflection of a shaft was simulated with FEA, which showed that the solution provides constant reaction forces and ensures nearly zero deflection at the supported main journals of a shaft during its rotation (during its geometry measurement). The article also presents an example of a design solution for a single counterweight.

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Section: Crankshaft Geometry Measuring Methodsmentioning

confidence: 99%

Method to Increase the Accuracy of Large Crankshaft Geometry Measurements Using Counterweights to Minimize Elastic Deformations

et al. 2020

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“…This is due to the non-linearities introduced primarily by the large reciprocating and rotating masses of the engine's piston assembly. 43,66 It is observed that the measured ICT data sufficiently match the ICT from the extended model deployed within the inverse problem method. As shown in Figure 5(b), the residuals between these ICT variations fluctuate at approximately two orders of magnitude less than the measured ICT data, which demonstrates a very small difference.…”

Section: Individual Case Studies Analysismentioning

confidence: 84%

“…This larger system of equations is therefore solved using the a piecewise Linear Time-Invariant (LTI) system solver, which is the default solver for the direct model. 43 _…”

Section: Extended Direct Crankshaft Dynamics Modelmentioning

confidence: 99%

A novel method for in-cylinder pressure prediction using the engine instantaneous crankshaft torque

Tsitsilonis

Theotokatos

2021

Proceedings of the Institution of Mechanical Engineers, Part M:

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Current practices of condition assessment in large marine engines are largely based on the measurement of cylinder pressure using external kits, which poses challenges due to sensors synchronisation and durability issues, as well as the inability to perform continuous monitoring. For addressing these challenges, this study aims at developing a novel method to solve the inverse problem of predicting the pressure variations in all engine cylinders, by using the Instantaneous Crankshaft Torque (ICT) measurement for large internal combustion engines. This method is developed by considering the Initial Value Problem (IVP) technique along with the integration of a direct crankshaft dynamics model incorporating the sensitivity parameters and stability criteria calculation based on the Lyapunov Exponent (LE) as well as a state-of-the-art Nonmonotone Self-Adaptive Levenberg-Marquardt (NSALMN) optimisation algorithm. The method is tested for a number of case studies using different combustion models based on the Weibe and sigmoid functions, as well as for healthy, degraded and faulty engine conditions. The derived results demonstrate adequate accuracy exhibiting a maximum error of 0.3% in the prediction of the mean peak in-cylinder pressure. The analysis of the calculated sensitivity parameters resulted in the identification of the parameters that significantly impact the solution, thus providing improved insights for selecting the developed method settings. The developed method renders the continuous and non-intrusive in-cylinder pressures monitoring feasible, by using a permanently installed shaft power metre sensor with higher sample rates.

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“…This model can be used as a dynamic excitation in simulation tests of torsional vibrations of crankshafts with a torsional vibration damper. The application of an excitation similar in nature to the real one will make it possible to fine-tune the damper parameters on the basis of a computer simulation [ 13 , 14 ].…”

Section: Introductionmentioning

confidence: 99%

Modeling the Influence of Engine Dynamics on Its Indicator Diagram

Deuszkiewicz

Dziurdź

Fabiś

2021

Sensors

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This article presents a proposal to describe the pressure changes in the combustion chamber of an engine as a function of the angle of rotation of the crankshaft, taking into account changes in rotational speed resulting from acceleration. The aim of the proposed model is to determine variable piston forces in simulation studies of torsional vibrations of a crankshaft with a vibration damper during the acceleration process. Its essence is the use of a Fourier series as a continuous function to describe pressure changes in one cycle of work. Such a solution is required due to the variable integration step during the simulation. It was proposed to determine the series coefficients on the basis of a Fourier transform of the averaged waveform of a discreet open indicator diagram, calculated for the registration of successive cycles. Recording of the indicative pressure waveforms and shaft angle sensor signals was carried out during tests on the chassis dynamometer. An analysis of the influence of the adopted number of series coefficients on the representation of signal energy was carried out. The model can also take into account the phenomenon of work cycle uniqueness by introducing random changes in the coefficients with magnitudes set on the basis of determined standard deviations for each coefficient of the series. An indispensable supplement to the model is a description of changes in the engine rotational speed, used as a control signal for the PID controller in the simulation of the load performed by the dynamometer. The accuracy of determining the instantaneous rotational speed was analyzed on the basis of signals from the crankshaft position angle sensor and the piston top dead center (TDC) sensor. Limitations resulting from the parameters of digital signal recording were defined.

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Systematic Investigation of a Large Two-Stroke Engine Crankshaft Dynamics Model

Cited by 8 publications

References 45 publications

Method to Increase the Accuracy of Large Crankshaft Geometry Measurements Using Counterweights to Minimize Elastic Deformations

Method to Increase the Accuracy of Large Crankshaft Geometry Measurements Using Counterweights to Minimize Elastic Deformations

A novel method for in-cylinder pressure prediction using the engine instantaneous crankshaft torque

Modeling the Influence of Engine Dynamics on Its Indicator Diagram

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