Numerical Analysis on Flow Characteristics of Air Starting Motor for Marine Medium-Speed Diesel Engine

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.

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

10.1115/icef2021-67715 ◽

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.

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A 1D–3D Approach for Fast Numerical Analysis of the Flow Characteristics of a Diesel Engine Exhaust Gas

Machines ◽

10.3390/machines9100239 ◽

2021 ◽

Vol 9 (10) ◽

pp. 239

Author(s):

Kyeong-Ju Kong

Keyword(s):

Diesel Engine ◽

Numerical Analysis ◽

Gas Flow ◽

Emission Control ◽

Flow Characteristics ◽

Exhaust System ◽

Exhaust Gas ◽

Analysis Method ◽

Numerical Analysis Method ◽

Control Devices

It is necessary to analyze the intake/exhaust gas flow of a diesel engine when turbocharger matching and when installing emission control devices such as exhaust gas recirculation (EGR), selective catalytic reduction (SCR), and scrubbers. Analyzing the intake/exhaust gas flow using a 3D approach can use various analytical models, but it requires a significant amount of time to perform the computation. An approach that combines 1D and 3D is a fast numerical analysis method that can utilize the analysis models of the 3D approach and obtain accurate calculation results. In this study, the flow characteristics of the exhaust gas were analyzed using a 1D–3D coupling algorithm to analyze the unsteady gas flow of a diesel engine, and whether the 1D–3D approach was suitable for analyzing exhaust systems was evaluated. The accuracy of the numerical analysis results was verified by comparison with the experimental results, and the flow characteristics of various shapes of the exhaust system of a diesel engine could be analyzed. Numerical analysis using the 1D–3D approach was able to be computed about 300 times faster than the 3D approach, and it was a method that could be used for research focused on the exhaust system. In addition, since it could quickly and accurately calculate intake/exhaust gas flow, it was expected to be used as a numerical analysis method suitable for analyzing the interaction of diesel engines with emission control devices and turbochargers.

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Emulation study on system characteristic of high pressure common-rail fuel injection system for marine medium-speed diesel engine

10.1063/1.5039056 ◽

2018 ◽

Author(s):

Qinpeng Wang ◽

Jianguo Yang ◽

Dong Xin ◽

Yuhai He ◽

Yonghua Yu

Keyword(s):

High Pressure ◽

Diesel Engine ◽

Fuel Injection ◽

Common Rail ◽

Injection System ◽

Fuel Injection System ◽

System Characteristic ◽

Medium Speed ◽

Marine Medium ◽

High Pressure Common Rail

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Numerical Analysis of Flow Characteristics in a Swirl Chamber Type Diesel Engine Depending on Passage Hole Type

ASME 2005 Internal Combustion Engine Division Fall Technical Conference (ICEF2005) ◽

10.1115/icef2005-1243 ◽

2005 ◽

Author(s):

Gyeung Ho Choi ◽

Tae Yun Kwon ◽

Ju Hee Yun ◽

Yon Jong Chung ◽

Chang Uk Ha ◽

...

Keyword(s):

Diesel Engine ◽

Numerical Analysis ◽

High Speed ◽

Flow Characteristics ◽

Complete Combustion ◽

Swirl Chamber ◽

High Speeds ◽

Hole Area ◽

High Speed Diesel ◽

Harmful Emissions

In a swirl chamber type diesel engine, a strong swirl is produced inside the swirl chamber during the compression stroke. By spraying the fuel into this chamber and thus forming a good mixture, the engine can obtain excellent combustion even at high speeds. Therefore, swirl chamber type diesel engines are favorable for high-speed operations, and because they can produce high power from a small size, they are used often for small, high-speed diesel engine applications. In order to simultaneously realize a reduction in harmful emissions and improvement in fuel consumption of the swirl chamber type diesel engine, reduction of the mixture formation period and complete combustion must be pursued; an optimum combustion chamber to achieve these tasks must first be designed. In this experiment, the effects of the area and the angle of the passage hole, which are the primary design factors of the swirl chamber type diesel engine, on the engine’s turbulent flow will be investigated. Using the commercial numerical analysis program the passage hole area and angle will be varied to analyze the intake and compression stages.

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