scholarly journals Development and Validation of 4 Stroke Marine Diesel Engine Numerical Model

2020 ◽  
Vol 3 (3) ◽  
pp. 359-372
Author(s):  
Vladimir Pelić ◽  
Tomislav Mrakovčić ◽  
Ozren Bukovac ◽  
Marko Valčić

Increasing demands on energy efficiency and environmental acceptance are being imposed on marine propulsion plants. The fulfilment of the conditions set by the MARPOL Convention, Annex VI, regarding the emissions from exhaust gases of marine diesel engines is of particular interest. This paper presents the development and validation of a zero-dimensional, single-zone diesel engine numerical model. Presented numerical model is based on the law of conservation of energy and mass and solving the resulting differential equations. The single-zone model will serve as the basis for a model where the cylinder space is divided into two or three zones during combustion. In this way, the multi-zone model will allow the modelling of nitrogen oxide emissions with satisfactory accuracy. Validation of the diesel engine model was carried out for the Wärtsilä 12V50DF 11700 kW motor designed to drive a synchronous alternator. Obtained results and deviations of certain parameters in the operation of the engine with respect to the data obtained from the measurements on the test bed, are more than satisfactory regarding complexity of the numerical model. This confirmed the usability of the model for research purposes to optimize the marine diesel engine.

Author(s):  
Huan Tu ◽  
Hui Chen

In actual operation process of a ship, the engine-propeller-hull is an integrated system with internal coupling effects, and thus there is a close interaction between the diesel engine propulsion system operation conditions and the ship manoeuvring motions. The propulsion system can experience large power fluctuation during manoeuvring, with considerable torque increase with regard to the stabilized value in straight course. However, the diesel engine propulsion system behaviour and ship manoeuvrability are usually studied separately as they are considered to belong to different disciplines. Thus, it is difficult to reflect the actual operating characteristics of the propulsion system and ship manoeuvring motion under coupled conditions in actual operation. To investigate the interaction between the propulsion system behaviour and the manoeuvrability of a large containership, this paper proposed a multi-disciplinary ship mobility model capable of coupling the marine diesel engine model and the ship manoeuvring model. In the engine model, the mean value modelling approach was adopted to simulate the two-stroke marine diesel engine considering the fact that it can capture the performance of the engine sub-systems including scavenging receiver, exhaust gas receiver, turbocharger, etc. In the manoeuvring model, the MMG-based method was used to simulate the ship manoeuvring motion with three degrees-of-freedom. The engine model and manoeuvring model were coupled through the propeller model that transferring propeller speed and torque between the two models. The coupled model was validated against the engine shop test data and the sea trial results. By applying this coupled model, a series of simulations of turning circle manoeuvres under various scenarios were performed. The simulation results presented the dynamic response of engine internal sub-systems during turning circle manoeuvring, explained the effect of the torque limiter on engine performance and ship manoeuvring motion, and analyse the influence of different propulsion system control strategies on the ship turning circle manoeuvrability. Although the presented case study has been validated on a specific ship, most of the discussed models have a general application.


Author(s):  
D. C. Lee ◽  
J. D. Yu

Under steady state condition, unstable torsional vibration normally does not occur in shafting systems using 4stroke diesel engine due to hysteresis damping of shafting system and relative damping of standard fitted damper. However, the unstable torsional vibration occurs on marine propulsion shafting systems due to slippage of a multi-friction clutch installed between increasing gear box and shaft generator. To identify this unstable vibration and make proper counter measure, the simulation for transient torsional vibration using the Newmark method is introduced in this paper. The mechanism of this unstable vibration is verified by vibration and noise measurements of the shafting system.


2021 ◽  
Author(s):  
Marcin Zacharewicz ◽  
Tomasz Kniaziewicz

The paper presents the results of model and empirical tests conducted for a marine diesel engine fueled by a blend of n-butanol and diesel oil. The research were aimed at assessing the usefulness of the proprietary diesel engine model in conducting research on marine engines powered by alternative fuels to fossil fuels. The authors defined the measures of adequacy. On their basis, they assessed the adequacy of the mathematical model used. The analysis of the results of the conducted research showed that the developed mathematical model is sufficiently adequate. Therefore, both the mathematical model and the computer program based on it will be used in further work on supplying marine engines with mixtures of diesel oil and biocomponents.


2018 ◽  
Vol 8 (12) ◽  
pp. 2489 ◽  
Author(s):  
Yu Ding ◽  
Congbiao Sui ◽  
Jincheng Li

The marine diesel engine combustion process is discontinuous and unsteady, resulting in complicated simulations and applications. When the diesel engine is used in the system integration simulation and investigation, a suitable combustion model has to be developed due to compatibility to the other components in the system. The Seiliger process model uses finite combustion stages to perform the main engine combustion characteristics and using the cycle time scale instead of the crank angle shortens the simulation time. Obtaining the defined Seiliger parameters used to calculate the engine performance such as peak pressure, temperature and work is significant and fitting process has to be carried out to get the parameters based on experimental investigation. During the combustion fitting, an appropriate mathematics approach is selected for root finding of non-linear multi-variable functions since there is a large amount of used experimental data. A direct injection marine engine test bed is applied for the experimental investigation based on the combustion fitting approach. The results of each cylinder and four-cylinder averaged pressure signals are fitted with the Seiliger process that is shown separately to obtain the Seiliger parameters, and are varied together with these parameters and with engine operating conditions to provide the basis for engine combustion modeling.


2017 ◽  
Vol 194 ◽  
pp. 55-70 ◽  
Author(s):  
Yuanyuan Tang ◽  
Jundong Zhang ◽  
Huibing Gan ◽  
Baozhu Jia ◽  
Yu Xia

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
Nikolaos-Alexandros Vrettakos

The operation during compressor surge of a medium speed marine diesel engine was examined on a test bed. The compressor of the engine's turbocharger was forced to operate beyond the surge line, by injecting compressed air at the engine intake manifold, downstream of the compressor during steady-state engine operation. While the compressor was surging, detailed measurements of turbocharger and engine performance parameters were conducted. The measurements included the use of constant temperature anemometry for the accurate measurement of air velocity fluctuations at the compressor inlet during the surge cycles. Measurements also covered engine performance parameters such as in-cylinder pressure and the impact of compressor surge on the composition of the exhaust gas emitted from the engine. The measurements describe in detail the response of a marine diesel engine to variations caused by compressor surge. The results show that both turbocharger and engine performance are affected by compressor surge and fast Fourier transform (FFT) analysis proved that they oscillate at the same main frequency. Also, prolonged steady-state operation of the engine with this form of compressor surge led to a non-negligible increase of NOx emissions.


2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Runzhi Wang ◽  
Xuemin Li ◽  
Yufei Liu ◽  
Wenjie Fu ◽  
Shuang Liu ◽  
...  

A novel control scheme based on multiple model predictive functional control (MMPFC) is proposed to solve the cumbersome and time-consuming parameters tuning of the speed controller for a marine diesel engine. It combines the MMPFC with traditional PID algorithm. In each local linearization, a first-order plus time delay (FOPTD) model is adopted to be the approximate submodel. To overcome the model mismatches under the load disturbance conditions, we introduce a method to estimate the open-loop gain of the speed control model, by which the predictive multimodels are modified online. Thus, the adaptation and robustness of the proposed controller can be improved. A cycle-detailed hybrid nonlinear engine model rather than a common used mean value engine model (MVEM) is developed to evaluate the control performance. In such model, the marine engine is treated as a whole system, and the discreteness in torque generation, the working imbalance among different cylinders, and the cycle delays are considered. As a result, more reliable and practical validation can be achieved. Finally, numerical simulation of both steady and dynamic performances of the proposed controller is carried out based on the aforementioned engine model. A conventional well-tuned PID with integral windup scheme is adopted to make a comparison. The results emphasize that the proposed controller is with stable and adaptive ability but without needing complex and tough parameters regulation. Moreover, it has excellent disturbance rejection ability by modifying the predictive multimodels online.


2013 ◽  
Vol 655-657 ◽  
pp. 98-104
Author(s):  
Hai Yan Wang ◽  
Lei Chen ◽  
Ji An

For matching various working condition of ship propulsion system, a modified mean value model of a large-scale low-speed directly reversible marine diesel engine is put forward. A starting and braking torque module is added to the conventional model. A new friction model which considers static friction is adopted. So, the new model can run smoothly across all propulsion working condition, such as starting, running, braking, reversing, etc. The dynamic simulation models of propeller running across four quadrants and ship longitudinal motion are given too. The 5S60MC marine diesel engine equipped on a 76000DWT bulk carrier is taken as an example. The simulation results show that steady data of diesel are in good accordance with test-bed data, and dynamic data match to ship sea trial data in crash stop condition. The best is to read these instructions and follow the outline of this text.


Author(s):  
George A. Livanos ◽  
George N. Simotas ◽  
George G. Dimopoulos ◽  
Nikolaos P. Kyrtatos

The dynamic behavior of a typical four-stroke, medium-speed, marine diesel engine driving a Controllable Pitch Propeller (CPP) is investigated during ship maneuvering including fast propeller pitch changes. A modular model has been developed in Simulink/Matlab for the simulation of the dynamics of ship propulsion. The developed model considers the ship propulsion system as a set of three main modules: the engine, the propeller and the ship hull. The developed ship propulsion dynamics model has been validated with a wide range of experimental data from a 500 kW test engine (MAN B&W 5L16/24), coupled to a four quadrant electric brake (AEG), installed at the test-bed of the Laboratory of Marine Engineering of the National Technical University of Athens (NTUA/LME). The model was then used for the investigation of marine diesel engine behavior during load changing including some extreme maneuvering case scenarios such as Crash Stop, Full Astern and Full Ahead maneuvers. The resulting ship propulsion model is a reduced order model, which can easily be used for detailed studies such as engine-control during fast transient loadings, with accuracy and small computational cost.


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