Analysis of combustion and emissions characteristics of a DI diesel engine fuelled with diesel/biodiesel/glycerol tert-butyl ethers mixture by altering compression ratio and injection timing

Fuel ◽  
2022 ◽  
Vol 315 ◽  
pp. 123200
Author(s):  
Abdülvahap Çakmak ◽  
Hakan Özcan
Author(s):  
Myung Yoon Kim ◽  
Ki Hyung Lee ◽  
Chang Sik Lee

An experimental investigation was performed on a small direct injection (DI) diesel engine equipped with a common-rail injection system to reduce exhaust emissions through HCCI (homogenous charge compression ignition) combustion. Recently, strict environmental standard requirements call for both lower fuel consumption and reduced emissions that could not be achieved by conventional diesel combustion. In this work experimental investigations to achieve simultaneous reduction of NOx and soot by combustion of more diluted fuel/air mixture before the start of ignition were carried out. To realize this fundamental concept, the experimental conditions including injection timing and EGR rate are varied with the different engine configurations. For reducing the deposition of early injected fuel, spray angle of injector is reduced to 60° and piston head shape also modified to fit with the new injector and to reduce the compression ratio to 15:1 for expanding the ignition delay to form diluted mixture before the ignition. Experimental results show that reduced spray angle with modified piston head allow very low NOx and soot emission level while maintaining the high IMEP of diesel combustion.


Energies ◽  
2019 ◽  
Vol 12 (14) ◽  
pp. 2644 ◽  
Author(s):  
Norhidayah Mat Taib ◽  
Mohd Radzi Abu Mansor ◽  
Wan Mohd Faizal Wan Mahmood

Blending diesel with biofuels, such as ethanol and palm oil methyl ester (PME), enhances the fuel properties and produces improved engine performance and low emissions. However, the presence of ethanol, which has a small cetane number and low heating value, reduces the fuel ignitability. This work aimed to study the effect of injection strategies, compression ratio (CR), and air intake temperature (Ti) modification on blend ignitability, combustion characteristics, and emissions. Moreover, the best composition of diesel–ethanol–PME blends and engine modification was selected. A simulation was also conducted using Converge CFD software based on a single-cylinder direct injection compression ignition Yanmar TF90 engine parameter. Diesel–ethanol–PME blends that consist of 10% ethanol with 40% PME (D50E10B40), D50E25B25, and D50E40B10 were selected and conducted on different injection strategies, compression ratios, and intake temperatures. The results show that shortening the injection duration and increasing the injected mass has no significant effect on ignition. Meanwhile, advancing the injection timing improves the ignitability but with weak ignition energy. Therefore, increasing the compression ratio and ambient temperature helps ignite the non-combustible blends due to the high temperature and pressure. This modification allowed the mixture to ignite with a minimum CR of 20 and Ti of 350 K. Thus, blending high ethanol contents in a diesel engine can be applied by advancing the injection, increasing the CR, and increasing the ambient temperature. From the emission comparison, the most suitable mixtures that can be operated in the engine without modification is D50E25B25, and the most appropriate modification on the engine is by increasing the ambient temperature at 350 K.


Author(s):  
Kamran Poorghasemi ◽  
Fathollah Ommi ◽  
Vahid Esfahanian

In DI Diesel engines NO and Soot trade off is an important challenge for Engineers. In this paper, at first, multiple injection strategy will be introduced as a useful way to reduce both NO and Soot emissions simultaneously. Then the effect of injection pressure in post injection on the engine emissions will be studied. Investigations have been conducted on DI diesel engine. To evaluate the benefits of multiple injection strategies and to reveal combustion mechanism, modified three dimensional CFD code KIVA-3V was used. Results showed that using post injection with appropriate dwell between injection pulses can be effective in simultaneously reduction of emissions. Based on computation results, NO reduction formation mechanism is a single injection with retarded injection timing. It is shown that reduced soot formation is because of the fact that the soot producing rich regions at the fuel spray head are not replenished by new fuel when the injection is stopped and then restarted. Also increasing injection pressure in post injection will reduce the Soot emission dramatically while NO is in control and it is due to increasing fuel burning rate in post injection pulse.


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