Modeling and performance analysis of diesel engine considering the heating effect of blow-by on cylinder intake gas

2021 ◽  
pp. 146808742110692
Author(s):  
Zhenyu Shen ◽  
Yanjun Li ◽  
Nan Xu ◽  
Baozhi Sun ◽  
Yunpeng Fu ◽  
...  

Recently, the stringent international regulations on ship energy efficiency and NOx emissions from ocean-going ships make energy conservation and emission reduction be the theme of the shipping industry. Due to its fuel economy and reliability, most large commercial vessels are propelled by a low-speed two-stroke marine diesel engine, which consumes most of the fuel in the ship. In the present work, a zero-dimensional model is developed, which considers the blow-by, exhaust gas bypass, gas exchange, turbocharger, and heat transfer. Meanwhile, the model is improved by considering the heating effect of the blow-by gas on the intake gas. The proposed model is applied to a MAN B&W low-speed two-stroke marine diesel engine and validated with the engine shop test data. The simulation results are in good agreement with the experimental results. The accuracy of the model is greatly improved after considering the heating effect of blow-by gas. The model accuracy of most parameters has been improved from within 5% to within 2%, by considering the heating effect of blow-by gas. Finally, the influence of blow-by area change on engine performance is analyzed with considering and without considering the heating effect of blow-by.

2013 ◽  
Vol 724-725 ◽  
pp. 1005-1008
Author(s):  
Ming Yue He ◽  
Hong Tao Gao ◽  
Yue Hui Wang ◽  
Wei Yan ◽  
Qing Yin ◽  
...  

For the purpose of providing a scientific reference for improving energy conservation and performance of marine diesel engine, the thermal balance analysis and exergy balance analysis and emission research on ethanol diesel-oil alternative fuel of the existing diesel engine are performed. All necessary data are obtained from an actual diesel engine of KTA50-M2 which is used in a boat located in Dalian. The result shows that engine performance parameters are of no big change, however, the exhaust emissions are significantly reduced.


Author(s):  
Harsh D. Sapra ◽  
Jaswinder Singh ◽  
Chris Dijkstra ◽  
Peter De Vos ◽  
Klaas Visser

Abstract Underwater exhaust systems are employed on board ships to allow zero direct emissions to the atmosphere with the possibility of drag reduction via exhaust gas lubrication. However, underwater expulsion of exhaust gases imparts high and dynamic back pressure, which can fluctuate in amplitude and time period as a ship operates in varying sea-states depending on its geographical location and weather conditions. Therefore, this research aims to experimentally investigate the performance of a marine diesel engine against varying amplitudes and time periods of dynamic back pressure at different sea-states due to underwater exhaust systems. In this study, a turbocharged, marine diesel engine was tested at different loads along the propeller curve against dynamic back pressure waves produced by controlling an electronic butterfly valve placed in the exhaust line after the turbine outlet. Engine performance was investigated against single and multiple back pressure waves of varying amplitudes and wave periods based on real sea-state conditions and wave data. We found that the adverse effects of dynamic back pressure on engine performance were less severe than those found against static back pressure. Governor control and turbocharger dynamics play an important role in keeping the fuel penalty and thermal loading low against dynamic back pressure. Therefore, a marine engine may be able to handle much higher levels of dynamic back pressures when operating with underwater exhaust systems in higher sea-states.


Author(s):  
Mayuko Nakamura ◽  
Atsuto Ohashi ◽  
Yoichi Niki ◽  
Akiko Masuda ◽  
Chiori Takahashi

Reduction of particulate matter (PM) is important issues even for shipping industry since PM harms the environment and human health. In order to reduce PM from marine diesel engines, we focused on components forming PM, elemental carbon (EC), organic carbon (OC), sulfate, and “others” (nitrate, bound water associated with sulfate, metal, ash and hydrogen associated with OC), and investigated the reduction effect of each component by changing fuel injection pressure of a four-stroke marine diesel engine at the two engine load points of 25% and 50%. At 50% load, the PM emissions decreased with increasing the fuel injection pressure, the reduction in the PM emissions which reflected the decrease in EC. At 25% load, the PM emissions did not decrease simply with the injection pressure since OC, sulfate, “others” components in addition to EC contributed to the injection pressure dependence of PM. The results suggest that behaviors of each component of PM should be grasped to achieve the appropriate reduction method of PM.


Sign in / Sign up

Export Citation Format

Share Document