An investigation of mixture formation and in-cylinder combustion processes in direct injection diesel engines using group-hole nozzles

2009 ◽  
Vol 10 (1) ◽  
pp. 27-44 ◽  
Author(s):  
J Gao ◽  
Y Matsumoto ◽  
M Namba ◽  
K Nishida
Author(s):  
M M Roy

This study investigated the effect of n-heptane and n-decane on exhaust odour in direct injection (DI) diesel engines. The prospect of these alternative fuels to reduce wall adherence and overleaning, major sources of incomplete combustion, as well as odorous emissions has been investigated. The n-heptane was tested as a low boiling point fuel that can improve evaporation as well as wall adherence. However, the odour is a little worse with n-heptane and blends than that of diesel fuel due to overleaning of the mixture. Also, formaldehyde (HCHO) and total hydrocarbon (THC) in the exhaust increase with increasing n-heptane content. The n-decane was tested as a fuel with a high cetane number that can improve ignition delay, which has a direct effect on wall adherence and overleaning. However, with n-decane and blends, the odour rating is about 0.5-1 point lower than for diesel fuel. Moreover, the aldehydes and THC are significantly reduced. This is due to less wall adherence and proper mixture formation.


2019 ◽  
Author(s):  
Federico Perini ◽  
Stephen Busch ◽  
Eric Kurtz ◽  
Alok Warey ◽  
Richard C. Peterson ◽  
...  

2015 ◽  
Vol 752-753 ◽  
pp. 922-927
Author(s):  
Sheng Li Wei ◽  
Kun Peng Ji ◽  
Xian Yin Leng ◽  
Xuan Liu

In order to promote the quality of mixture and improve the fuel spray spatial distribution, enhancing airflow movement in a combustion chamber, a new swirl chamber combustion system in DI (direct injection) diesel engines is proposed based on conical-spray. Numerical simulations have been conducted by using the FIRE v2008 code. Several different widths of passage and spray angles are investigated in a single cylinder 135 diesel engine. The combustion and emissions performance were investigated by different conical-spray nozzles and combustion chambers with a constant compression ratio. The results show that using this combustion system, the mixture formation and combustion processes have been improved by a certain longitudinal swirl when the air is squished into the swirl chamber through the relative narrow passage. Moreover, the formation of homogeneous mixture is accelerated and the combustion is improved compared with that of conventional combustion system. The cases show the passage width of 5mm and conical spray cone angle of 140° has a better performance in the new combustion system.


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