Two-part modelling approach for ship engine simulations

2015 ◽  
Author(s):  
M. Godjevac ◽  
P. de Vos ◽  
H. Zhou ◽  
C. Thiem
Keyword(s):  
Mean Value ◽  
Propulsion System ◽  
Component Model ◽  
First Principle ◽  
Transient Conditions ◽  
Ship Propulsion ◽  
Engine Model ◽  
Component Models ◽  
Modelling Approach

When simulating a ship propulsion system, it is often required to evaluate various characteristics of a ship propulsion system and the selected modelling approach changes according to the goal of the simulation. For example, data-based models are sufficient for simulations of steady state conditions while first principle models are more suitable for transient conditions. Additionally, it is often necessary to compare different propulsion configurations. For component models, this might require different modelling approaches to describe various performances and/or different sets of parameters used to describe different propulsion configurations. Even though there are various databases of ship component models, none of them allows the user to change the modelling approach or pre-set values of parameters used to describe the component models. In order to allow the changing of the modelling approach together with the parameters of the component models, a novel two-part modelling approach is proposed in this paper. The proposed approach separates the component model into two parts: process and parametric part. By adjusting the process part of the component model, the modelling approach can easily be changed. And by adjusting the parametric part of the component model, it is possible to adjust the component’s characteristics and accommodate different configurations. In this investigation, a mean value first principle diesel engine model has been selected as a case study to demonstrate the flexibility of the proposed approach. As shown in the paper, the proposed approach allows the user to combine the benefits of a first principle model with the accuracy of the data based models. Additionally, the functional mock-up interface (FMI) standard has been used in the investigation to show that the proposed approach can be used in different software environments.

First Principle-Based Control Oriented Model of a Gasoline Engine

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Ahmed Yar ◽  
A. I. Bhatti ◽  
Qadeer Ahmed
Keyword(s):  
Mathematical Model ◽  
Gasoline Engine ◽  
Mean Value ◽  
First Principle ◽  
Unified Framework ◽  
Engine Model ◽  
Proposed Model ◽  
Suitable Form ◽  
Speed Fluctuations ◽  
The Mathematical Model

A first principle based-control oriented gasoline engine model is proposed that is based on the mathematical model of the actual piston and crankshaft mechanism. Unlike conventional mean value engine models (MVEMs), which involve approximating the torque production mechanism with a volumetric pump, the proposed model obviates this rather over-simplistic assumption. The alleviation of this assumption leads to the additional features in the model such as crankshaft speed fluctuations and tension in bodies forming the mechanism. The torque production dynamics are derived through Lagrangian mechanics. The derived equations are reduced to a suitable form that can be easily used in the control-oriented model. As a result, the abstraction level is greatly reduced between the engine system and the mathematical model. The proposed model is validated successfully against a commercially available 1.3 L gasoline engine. Being a transparent and more capable model, the proposed model can offer better insight into the engine dynamics, improved control design and diagnosis solutions, and that too, in a unified framework.

Cyclic torque imbalance detection in gasoline engines using a uniform second-order sliding mode observer

2019 ◽  
Vol 233 (13) ◽  
pp. 3515-3527 ◽  
Author(s):  
Raheel Anjum ◽  
Aamer Iqbal Bhatti ◽  
Ahmed Yar ◽  
Qadeer Ahmed
Keyword(s):  
Sliding Mode ◽  
Research Work ◽  
Angular Speed ◽  
Mean Value ◽  
Second Order ◽  
Sliding Mode Observer ◽  
First Principle ◽  
Engine Torque ◽  
Engine Model ◽  
Second Order Sliding Mode

Engine torque imbalance is a wide-ranging problem which is caused due to variance of the combustion mixture in the engine cylinder. In this research work, cyclic torque imbalance detection is carried out by formulating a uniform second-order sliding mode observer using the First Principle–based Engine Model. Oscillations in the crankshaft angular speed were modeled in the novel First Principle–based Engine Model, which were suppressed in the Mean Value Engine Models. Cyclic torque imbalance is simulated at multiple instances by varying the injected fuel mass. Estimation of the net piston force is carried out for cyclic torque imbalance detection using rotational dynamics of the engine model. This force is treated as unknown input to the torque production subsystem of the model. Cyclic torque imbalance detection is validated using the GT-Power engine model. Variations in the cyclic torque were detected proximate to actual values which demonstrated validity of the proposed technique.

Multi-Fidelity Kriging-Based Optimization of Engine Subsystem Models With Medial Meshes

2018 ◽  
Author(s):  
Hau Kit Yong ◽  
Leran Wang ◽  
David J. J. Toal ◽  
Andy J. Keane ◽  
Felix Stanley
Keyword(s):  
Optimum Design ◽  
Computational Cost ◽  
Optimization Approach ◽  
Engine Model ◽  
Solid Models ◽  
Medial Surfaces ◽  
First Time ◽  
Kriging Approach ◽  
Modelling Approach

Engine subsystem models are not commonly used in design optimization studies as it is computationally expensive to solve these models for a large number of iterations. To reduce the computational cost of such optimizations, a novel multi-fidelity Kriging-based optimization approach is proposed that uses shell FEMs to provide a low-fidelity response and solid FEMs to provide a high-fidelity response. This marks the first time that shell and solid models are used together in a multi-fidelity surrogate modelling approach. The shell FEMs are generated from medial surfaces that are extracted from solid component geometries in a semi-automatic manner. This approach is applied to a case study for optimizing the intercasing subsystem from the CRESCENDO whole engine model. The results show that the optimum design found by the multi-fidelity Kriging approach was on par with the optimum design found by a single-fidelity Kriging approach using only solid FEMs which is more than twice as expensive to run. The shell and solid FEMs were also shown to be well-correlated such that optimization studies employing only the shell FEMs by themselves could generate designs that are feasible with respect to the design constraints imposed on the solid model.

Fuel consumption and emission reduction of marine lean-burn gas engine employing a hybrid propulsion concept

2021 ◽  
pp. 146808742110163
Author(s):  
Sadi Tavakoli ◽  
Kamyar Maleki Bagherabadi ◽  
Jesper Schramm ◽  
Eilif Pedersen
Keyword(s):  
Fuel Consumption ◽  
Emission Reduction ◽  
Maximum Load ◽  
Combustion Efficiency ◽  
Propulsion System ◽  
Lean Burn ◽  
Transient Conditions ◽  
Hybrid Propulsion ◽  
Engine Model ◽  
Hybrid Configuration

As the emission legislation becomes further constraining, all manufacturers started to fulfill the future regulations about the prime movers in the market. Lean-burn gas engines operating under marine applications are also obligated to enhance the performance with a low emission level. Lean-burn gas engines are expressed as a cleaner source of power in steady loading than diesel engines, while in transient conditions of sea state, the unsteadiness compels the engine to respond differently than in the steady-state. This response leads to higher fuel consumption and an increase in emission formation. In order to improve the stability of the engine in transient conditions, this study presents a concept implementing a hybrid configuration in the propulsion system. An engine model is developed and validated in a range of load and speed by comparing it with the available measured data. The imposed torque into the developed engine model is smoothed out by implementing the hybrid concept, and its influence on emission reduction is discussed. It is shown that with the hybrid propulsion system, the NOX reduces up to 40% because of the maximum load reduction. Moreover, eliminating the low load operation by a Power Take In during incomplete propeller immersion, the methane slip declines significantly due to combustion efficiency enhancement.

PID-LIKE FLC FOR FOUR CYLINDERS MEAN VALUE GASOLINE ENGINE MODEL IN IDLE MODE

2018 ◽  
Vol 09 (02) ◽  
pp. 114-130
Author(s):  
Mohammed Hassan ◽  
◽  
Muslim Abdali ◽  
Keyword(s):  
Gasoline Engine ◽  
Mean Value ◽  
Idle Mode ◽  
Engine Model ◽  
Four Cylinders

Investigation of a New Approach to Predict Water Quality Extremes with a Case Study of Chemical Determinands in Stream Water

1991 ◽  
Vol 24 (6) ◽  
pp. 25-33
Author(s):  
A. J. Jakeman ◽  
P. G. Whitehead ◽  
A. Robson ◽  
J. A. Taylor ◽  
J. Bai
Keyword(s):  
Water Quality ◽  
Stream Water ◽  
Probability Distributions ◽  
Management Strategies ◽  
Hybrid Modelling ◽  
Trend Model ◽  
Environmental Extremes ◽  
Modelling Approach

The paper illustrates analysis of the assumptions of the statistical component of a hybrid modelling approach for predicting environmental extremes. This shows how to assess the applicability of the approach to water quality problems. The analysis involves data on stream acidity from the Birkenes catchment in Norway. The modelling approach is hybrid in that it uses: (1) a deterministic or process-based description to simulate (non-stationary) long term trend values of environmental variables, and (2) probability distributions which are superimposed on the trend values to characterise the frequency of shorter term concentrations. This permits assessment of management strategies and of sensitivity to climate variables by adjusting the values of major forcing variables in the trend model. Knowledge of the variability about the trend is provided by: (a) identification of an appropriate parametric form of the probability density function (pdf) of the environmental attribute (e.g. stream acidity variables) whose extremes are of interest, and (b) estimation of pdf parameters using the output of the trend model.

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