Analysis and characterization of a marine turbocharger’s unstable performance

Author(s):  
Nikolaos Alexandros Vrettakos

In this article, the results of an extended set of experiments on a turbocharged four-stroke marine diesel engine are presented. By modifying the engine’s intake manifold and injecting compressed air into it, it was possible to raise the pressure downstream of the turbocharger’s compressor and force it into unstable operation. Tests were performed through the entire operating envelope of the engine. Depending on the operating mode of the engine (steady state, transient) and the operating load, it was possible to identify different forms of compressor instability. The equipment used enabled the creation of detailed profiles of engine and turbocharger performance. By applying time- and frequency-domain analysis tools, the measurements were utilized to characterize the extent and form of instability taking place at each operating point of the engine. The results and correlations made along with remarks on the instrumentation used during the experiments can be used to provide quantitative input for surge control–oriented models and the development of control systems for surge avoidance and mitigation. Moreover, they will be used as experimental reference for the validation of a surge model-engine simulation code combination.

1999 ◽  
Vol 43 (04) ◽  
pp. 201-217
Author(s):  
P. Chesse ◽  
B. Inozu ◽  
P. Roy ◽  
X. Tauzia ◽  
J. F. Hetet

This paper describes a diesel engine simulation code, named SELENDIA, jointly developed by EcoleCentrale de Nantes, France, and the University of New Orleans. The adopted models for steady-state and transient response simulation are briefly introduced in addition to various validation results. The capabilities of the code are illustrated by a study regarding the transient response of a sequentially turbocharged marine diesel engine as well as the simulation of engine performance under extreme conditions and the investigation of engine pollutant emissions.


2004 ◽  
Vol 41 (03) ◽  
pp. 95-101
Author(s):  
P. Chesse ◽  
D. Chalet ◽  
X. Tauzia ◽  
J. F. Hetet ◽  
B. Inozu

This paper presents a marine diesel engine simulation code designed for real-time performance. The main novelty is that the various equations are derived from the laws of thermodynamics, thus guaranteeing qualitatively accurate predictions and allowing for easy use with any type of engine. The code is based on the "filling and emptying" method with various simplifications to achieve real-time performance. A number of failure models were added to interface the code with a propulsion training application. This was done in order to educate crews on failure detection and the management of emergencies.


Author(s):  
Ioannis Vlaskos ◽  
Ennio Codan ◽  
Nikolaos Alexandrakis ◽  
George Papalambrou ◽  
Marios Ioannou ◽  
...  

The paper describes the design process for a controlled pulse turbocharging system (CPT) on a 5 cylinder 4-stroke marine engine and highlights the potential for improved engine performance as well as reduced smoke emissions under steady state and transient operating conditions, as offered by the following technologies: • controlled pulse turbocharging, • high pressure air injection onto the compressor impeller as well as into the air receiver, and • an electronic engine control system, including a hydraulic powered electric actuator. Calibrated engine simulation computer models based on the results of tests performed on the engine in its baseline configuration were used to design the CPT components. Various engine tests with CPT under steady state and transient operating conditions show the engine optimization process and how the above-mentioned technologies benefit engine behavior in both generator and propeller law operation.


Author(s):  
J. K. Woodard ◽  
G. E. Johnson ◽  
R. L. Lott

Abstract The design of a turbocharged, gasoline fueled, four-stroke engine is considered with the goal of selecting design and operating variables to minimize fuel consumption. The development of the engine simulation code and the effect of model assumptions on the results are presented. The optimization includes constraints on detonation, exhaust emissions, and torque. Variables are bounded to assure the validity of the simulation. A number of observations about the interaction between the thermo-fluid model and the nonlinear programming algorithm are made and general strategies to enhance the optimization under such circumstances are discussed. The method is illustrated by exploring the design of a turbocharged Buick V-6 engine on an IBM PC/AT personal computer. Stock design variables, and operating variables that provided a design away from the constraints imposed by torque, emission, and detonation were chosen as the starting point for the optimization. Application of the optimization strategy resulted in an 18 percent reduction in predicted fuel consumption at 50 miles per hour. Significant specific recommendations included a reduction in combustion chamber volume, an increase in intake manifold pressure, an increase in intake duration, a decrease in exhaust duration, and relatively small changes in valve geometry. The paper clearly demonstrates that it is feasible to do relatively sophisticated engineering design and optimization on personal computers, and it sets the stage for further work in this area.


2014 ◽  
Vol 663 ◽  
pp. 336-341 ◽  
Author(s):  
Mohd Farid Muhamad Said ◽  
Zulkarnain Abdul Latiff ◽  
Aminuddin Saat ◽  
Mazlan Said ◽  
Shaiful Fadzil Zainal Abidin

In this paper, engine simulation tool is used to investigate the effect of variable intake manifold and variable valve timing technologies on the engine performance at full load engine conditions. Here, an engine model of 1.6 litre four cylinders, four stroke spark ignition (SI) engine is constructed using GT-Power software to represent the real engine conditions. This constructed model is then correlated to the experimental data to make sure the accuracy of this model. The comparison results of volumetric efficiency (VE), intake manifold air pressure (MAP), exhaust manifold back pressure (BckPress) and brake specific fuel consumption (BSFC) show very well agreement with the differences of less than 4%. Then this correlated model is used to predict the engine performance at various intake runner lengths (IRL) and various intake valve open (IVO) timings. Design of experiment and optimisation tool are applied to obtain optimum parameters. Here, several configurations of IRL and IVO timing are proposed to give several options during the engine development work. A significant improvement is found at configuration of variable IVO timing and variable IRL compared to fixed IVO timing and fixed IRL.


Author(s):  
Gianmario L. Arnulfi ◽  
Carlo Cravero ◽  
Martino Marini

Natural gas carrying from production sites to users’ facilities is made by marine shipping in liquid phase or by terrestrial pumping in gaseous phase through long pipelines. In the latter case several storage stations are distributed along the pipeline nets to move the natural gas from its deposits to users’ terminals. Storage stations are set up to compensate seasonal fluctuations of the consumer demand versus methane supply, storing the gas in various kinds of reservoirs. In most of such plants centrifugal compressors are used, where the energy and the time that a complete charge takes are affected by the operation scheduling of the compressor from the minimum to the maximum storage levels. While the pressure in the reservoir enforces the instant operation pressure, the flow rate is limited within a quite wide range. Here an in-house code, based on the lumped parameter approach and a quasi-steady dynamics, is applied to a complete charge. The natural gas behavior is modeled by the pseudo-ideal gas in order to get a fair accuracy keeping the usual gas dynamics equations. The compression path has been parameterized and a multi objective optimization, embedding the simulation code, has been implemented to find the most suitable management of the compression station for the minimization of time and energy. The most significant paths are analyzed to pick out the effects of the compression strategy.


2002 ◽  
Vol 39 (01) ◽  
pp. 21-28
Author(s):  
Kevin Logan ◽  
Bahadir Inozu ◽  
Philippe Roy ◽  
Jean-Francçois Hetet ◽  
Pascal Chesse ◽  
...  

Automated monitoring systems are now the standard on most large vessels; however, few are equipped with diagnostic systems. This paper presents new developments in the area of fault diagnosis based on intelligent software agents. The research objective was to design an agent capable of continuous real-time machine learning by using an artificial neural network known as the cerebellar model articulation controller (CMAC). An engine simulator that can model both normal and faulty engine operations was used to develop the learning system controller in a flexible and cost-efficient manner. This paper provides a description of the selected CMAC, a brief overview of the real-time engine simulator and its integration with the learning system as well as a few results.


Author(s):  
G. Papalambrou ◽  
N. P. Kyrtatos

This paper addresses the reduction of smoke emissions and improvement of load acceptance in a turbocharged marine diesel engine, during transient operation involving rapid load increases. Model Predictive Control (MPC) provided the optimal quantity of injected air in the engine while minimizing smoke density (opacity), with constraint not to exceed a limit in intake manifold pressure, in order to avoid surge in the compressor. System identification methods were used to determine control models at various operating points of the engine. Transient response experiments were performed on a full-scale marine diesel test engine on a transient test bed, using real-time MPC configuration. Results comparing the opacity under air injection model predictive control with the standard engine operation without air injection, during the same transient, show reduction in opacity level while avoiding surge.


2004 ◽  
Vol 126 (1) ◽  
pp. 92-101 ◽  
Author(s):  
S. Campanari ◽  
L. Boncompagni ◽  
E. Macchi

This paper investigates energy savings and economic aspects related to the use of microturbine generators in commercial buildings either for cogeneration electricity+heat or for trigeneration (electricity, heat and cold). In all calculations, reference is made to a 25kWel-class commercial microturbine generator (MTG), tested by the authors. Various plant schemes are considered, based on one or several MTG sets. The possibility of generating heat and/or cold also by an electrically driven inverse-cycle air-to-water heat pump/chiller system is also considered. Calculations are based on the simulation code TRIGEN developed by the authors. The code provides detailed energy, economic and emission yearly balances. The plant operating mode is optimized in each time interval. The results indicate that, due to large load variations, (i) the optimum turbine nominal output is in the range of about 70% of the electric peak demand, (ii) energy savings are marginal, (iii) advantages related to splitting the overall capacity on more than one unit are marginal, and (iv) the addition of an absorption machine improves the plant economics.


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