Optimization of a Marine Medium-Speed Engine With Multi-Injector System by 1D Predictive Simulation

2021 ◽  
Author(s):  
Dai Liu ◽  
Peng Zhang ◽  
Long Liu ◽  
Qian Xia ◽  
Xiuzhen Ma
Keyword(s):  
Diesel Engine ◽  
Thermal Efficiency ◽  
Engine Performance ◽  
Nox Emission ◽  
Combustion Model ◽  
Injection Timing ◽  
Engine Model ◽  
Medium Speed ◽  
Injector System ◽  
Marine Medium

Abstract The thermal efficiency and emission of large bore marine medium-speed diesel engine are required to be improved under the stringent legislations. A multi-injector system has been proposed in order to improve the thermal efficiency and NOx emission instantaneously. However, application of the multi-injector system increased the complexity of parameter optimization and control. To develop proper control strategy of the novel multi-injector system, a 1D engine model of the original engine configurations was developed initially, including a predictive combustion model in commercial 1D simulation program (GT-Power). After calibrated by test results and literature data under various engine loads, the engine model was modified from a central single injector engine to a multi-injector engine. On the basis of a conventional direct-injection diesel engine, another two injectors were added to the cylinder as side injectors in the model. And the fundamental combustion characteristics and engine performance of the marine medium-speed diesel engine with multi-injector are investigated under various injection quantity ratio between the central injector and side injectors. The effects of injection timing and split injection are also studied by simulation. The result indicated that the effective thermal efficiency and NOx emission of the medium speed marine diesel engine are optimized instantaneously by changing the injection strategies of the central and side injectors. Finally, the preferred injection strategy is proposed by the 1D model.

scholarly journals Optimization of Marine Medium Speed Diesel Engine Performance based on Multi-Injector System

2021 ◽  
Vol 236 ◽  
pp. 01026
Author(s):  
Dai Liu ◽  
Yingzhu Guo ◽  
Long Liu ◽  
Qian Xia ◽  
Yong Gui
Keyword(s):  
Diesel Engine ◽  
Thermal Efficiency ◽  
Fuel Injection ◽  
Engine Performance ◽  
Injection Rate ◽  
Nox Emission ◽  
Spray Angle ◽  
Medium Speed ◽  
Injector System ◽  
Marine Medium

Multi-injector system is potential to improve thermal efficiency and NOx emission of diesel engine at the same time. In order to optimize the combustion and emission of Marine medium speed diesel engine, the engine combustion with a multi-injector system is simulated and analyzed by CFD software Converge. In this research, two injectors are installed at the side of the cylinder head while the central injector is maintained. Various injection directions of side injectors and injection strategies of multi-injector system are simulated to optimize the fuel spray and combustion. The analysis results show that the spray angle of the side injector plays a key role for effective thermal efficiency improvement, since complex spray jet-jet interaction and spray impingement may deteriorate the combustion if the arrangement of spray angle was not set properly. Once the fuel injection direction has been optimized, the fuel ratio of the three injectors is optimized and improved the effective thermal efficiency with lower NOx emission. The results show that the two side injectors could increase the fuel injection rate into the cylinder, leading to high brake power and consequently increased the thermal efficiency by 1.26% and decreased the NOx emission by 16% for the best optimization.

NOx Emissions From a Diesel Engine Fueled With Natural Gas

1995 ◽  
Vol 117 (4) ◽  
pp. 290-296 ◽  
Author(s):  
Y. Tao ◽  
K. B. Hodgins ◽  
P. G. Hill
Keyword(s):  
Diesel Engine ◽  
Natural Gas ◽  
Ignition Delay ◽  
Substantial Reduction ◽  
Equilibrium Concentration ◽  
Nox Emission ◽  
Combustion Model ◽  
Injection Timing ◽  
Exhaust Pipe ◽  
Nox Emissions

The performance and emission characteristics of a single-cylinder two-stroke diesel engine fueled with direct injection of natural gas entrained with pilot diesel ignition enhancer have been measured. The thermal efficiency of the optimum gas-diesel operation was shown to exceed that of the conventional diesel at full load, but to be less at part load where the ignition delay was excessive. At high load, where the NOx emission problem is most serious, substantial reduction in NOx emission rate was obtained with delay of injection timing and also with use of exhaust gas recirculation. Measured cylinder pressures were used with a three-zone combustion model to determine ignition delay and the temperatures of the burned gas. The predicted NOx emissions based on equilibrium concentration of NO at the maximum burned gas temperature were found to correlate closely with exhaust pipe measurements of NOx.

A Study on Reducing the NOx Emission of the L21/31 Medium-Speed Marine Diesel Engine for IMO Tier Emission Legislation

2013 ◽  
Vol 291-294 ◽  
pp. 1920-1924
Author(s):  
Min Xiao ◽  
Hui Chen
Keyword(s):  
Numerical Simulation ◽  
Diesel Engine ◽  
Fuel Injection ◽  
Nox Emission ◽  
Injection Timing ◽  
Marine Diesel Engine ◽  
Nox Emissions ◽  
Variable Parameters ◽  
Medium Speed ◽  
Marine Diesel

The KIVA-3V program was used to make numerical simulation for L21/31 type of medium-speed marine diesel engine about the NOx emissions and the affection of NOx changing process on different variable parameters under the Tier Ⅱstandard. On this basis, a discussion towards the NOx emission of the model fueling with dimethyl ether (DME) to meet the Tier Ⅲ standard is offered. The results show that reducing the intake temperature, load and speed, postponing the fuel injection timing and intake lag angle properly can decrease the NOx emissions within the limits of NOx in TierⅡ standard. Comparing the results of the numerical simulation of DME and diesel fuel, the NOx emission of the former one is 60.85% of the latter one, and the NOx emission of changing variable parameters on DME engine is 35.56% of the original type of diesel engine, very close to the Tier Ⅲ.

Research on NOx Emission Characteristics of Medium Speed Diesel Engine

2013 ◽  
Vol 744 ◽  
pp. 215-218
Author(s):  
Zhong Min Liu ◽  
Jin Long Yan ◽  
Jian Feng Li
Keyword(s):  
Finite Element ◽  
High Pressure ◽  
Diesel Engine ◽  
Element Model ◽  
Nox Emission ◽  
Injection Timing ◽  
Emission Characteristics ◽  
Miller Cycle ◽  
Medium Speed ◽  
Charge Temperature

In order to research the NOx emission characteristics of the medium speed diesel engine DN8340, a finite element model is built. Calculate the influence of changing the intake charge temperature and injection timing on NOx emission, and forecast how it works to decrease the intake charge temperature and delay injection timing by the methods of Miller-cycle, oscillating cooling piston and electronic controlled high pressure common rail. The calculation result shows that Decreasing the intake charge temperature and delaying the injection timing can reduce the NOx emission to 2.22g/kWh effectively which meets the requirement of IMO TierIII.

SFC Benefit With Split Injection in Two-Stroke Diesel Engine

2009 ◽  
Author(s):  
Manoj Gokhale ◽  
Bhaskar Tamma ◽  
Roy J. Primus ◽  
Benzi John
Keyword(s):  
Diesel Engine ◽  
Engine Performance ◽  
System Level ◽  
Injection Timing ◽  
Fuel Injector ◽  
Cfd Model ◽  
Split Injection ◽  
Fuel Savings ◽  
Medium Speed ◽  
Data Calibration

The influence of split-injection on engine performance is studied using system and in-cylinder simulation of a two-stroke medium speed diesel engine. System level models for the engine and fuel system and a multi-dimension CFD model for the combustion chamber were developed and calibrated with experimental data. Calibration of these models from the available test data is discussed and calibration results are presented. The SFC and NOx predictions show good sensitivity to injection timing variation. These calibrated models were then used to simulate split injection through the modification of the fuel injector. Split injection achieved through this modification results in fuel savings while maintaining same NOx levels.

scholarly journals Support vector machine for a diesel engine performance and NOx emission control-oriented model

2020 ◽  
Vol 53 (2) ◽  
pp. 13976-13981
Author(s):  
Masoud Aliramezani ◽  
Armin Norouzi ◽  
Charles Robert Koch
Keyword(s):  
Support Vector Machine ◽  
Diesel Engine ◽  
Emission Control ◽  
Engine Performance ◽  
Nox Emission ◽  
Support Vector

Two-Stroke Marine Diesel Engine Variable Injection Timing System Performance Evaluation and Optimum Setting for Minimum Fuel Consumption at Acceptable NOx Levels

2014 ◽  
Author(s):  
Dimitrios T. Hountalas ◽  
Spiridon Raptotasios ◽  
Antonis Antonopoulos ◽  
Stavros Daniolos ◽  
Iosif Dolaptzis ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Engine Performance ◽  
Operating Conditions ◽  
Specific Fuel Consumption ◽  
Injection Timing ◽  
Nox Emissions ◽  
Pressure Measurements ◽  
Cylinder Pressure ◽  
Start Of Injection

Currently the most promising solution for marine propulsion is the two-stroke low-speed diesel engine. Start of Injection (SOI) is of significant importance for these engines due to its effect on firing pressure and specific fuel consumption. Therefore these engines are usually equipped with Variable Injection Timing (VIT) systems for variation of SOI with load. Proper operation of these systems is essential for both safe engine operation and performance since they are also used to control peak firing pressure. However, it is rather difficult to evaluate the operation of VIT system and determine the required rack settings for a specific SOI angle without using experimental techniques, which are extremely expensive and time consuming. For this reason in the present work it is examined the use of on-board monitoring and diagnosis techniques to overcome this difficulty. The application is conducted on a commercial vessel equipped with a two-stroke engine from which cylinder pressure measurements were acquired. From the processing of measurements acquired at various operating conditions it is determined the relation between VIT rack position and start of injection angle. This is used to evaluate the VIT system condition and determine the required settings to achieve the desired SOI angle. After VIT system tuning, new measurements were acquired from the processing of which results were derived for various operating parameters, i.e. brake power, specific fuel consumption, heat release rate, start of combustion etc. From the comparative evaluation of results before and after VIT adjustment it is revealed an improvement of specific fuel consumption while firing pressure remains within limits. It is thus revealed that the proposed method has the potential to overcome the disadvantages of purely experimental trial and error methods and that its use can result to fuel saving with minimum effort and time. To evaluate the corresponding effect on NOx emissions, as required by Marpol Annex-VI regulation a theoretical investigation is conducted using a multi-zone combustion model. Shop-test and NOx-file data are used to evaluate its ability to predict engine performance and NOx emissions before conducting the investigation. Moreover, the results derived from the on-board cylinder pressure measurements, after VIT system tuning, are used to evaluate the model’s ability to predict the effect of SOI variation on engine performance. Then the simulation model is applied to estimate the impact of SOI advance on NOx emissions. As revealed NOx emissions remain within limits despite the SOI variation (increase).

Diesel engine performance mapping using a parametrized mixing time model

2017 ◽  
Vol 19 (2) ◽  
pp. 202-213 ◽  
Author(s):  
Michal Pasternak ◽  
Fabian Mauss ◽  
Christian Klauer ◽  
Andrea Matrisciano
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Mixing Time ◽  
Combustion Process ◽  
Engine Performance ◽  
Injection Timing ◽  
Engine Control ◽  
Reactor Model ◽  
Time Model ◽  
Tabulated Chemistry

A numerical platform is presented for diesel engine performance mapping. The platform employs a zero-dimensional stochastic reactor model for the simulation of engine in-cylinder processes. n-Heptane is used as diesel surrogate for the modeling of fuel oxidation and emission formation. The overall simulation process is carried out in an automated manner using a genetic algorithm. The probability density function formulation of the stochastic reactor model enables an insight into the locality of turbulence–chemistry interactions that characterize the combustion process in diesel engines. The interactions are accounted for by the modeling of representative mixing time. The mixing time is parametrized with known engine operating parameters such as load, speed and fuel injection strategy. The detailed chemistry consideration and mixing time parametrization enable the extrapolation of engine performance parameters beyond the operating points used for model training. The results show that the model responds correctly to the changes of engine control parameters such as fuel injection timing and exhaust gas recirculation rate. It is demonstrated that the method developed can be applied to the prediction of engine load–speed maps for exhaust NOx, indicated mean effective pressure and fuel consumption. The maps can be derived from the limited experimental data available for model calibration. Significant speedup of the simulations process can be achieved using tabulated chemistry. Overall, the method presented can be considered as a bridge between the experimental works and the development of mean value engine models for engine control applications.

Water Addition in Diesel Engine Intake for NOx Reduction: Comparison of Modeling and Experiments

2003 ◽  
Author(s):  
Bhaskar Tamma ◽  
Juan Carlos Alvarez ◽  
Aaron J. Simon
Keyword(s):  
Diesel Engine ◽  
Fuel Efficiency ◽  
Nox Reduction ◽  
Engine Performance ◽  
Thermodynamic Cycle ◽  
Nox Emission ◽  
Water Addition ◽  
Predictive Tool ◽  
Fuel Flow ◽  
Influence Of Water

Reduction in emissions, especially NOx has been the main study of various engine researchers in the light of stringent emission norms. To reduce the time and cost involved in testing these technologies, engine thermodynamic cycle predictive tools are used. The present work uses one such predictive tool (GT Power from Gamma Technologies) for predicting the influence of water addition in a turbocharged 6-cylinder diesel engine intake on engine performance and NOx emissions. The experiments for comparison with modeling included the introduction of liquid water in the engine intake stream, between the compressor and intercooler ranging from 0 to 100% of fuel flow rate. NOx emission reduced linearly with water addition with reduction of 63% with less than 1% penalty on fuel efficiency at 100% water addition. The GT Power model predicted the performance within 5% of experimental data and NOx emission within 10% of the experiments.

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