Effect of High Pressure Post Injection on Soot and NO Trade-Off in a DI Diesel Engine

2010 ◽  
Author(s):  
Kamran Poorghasemi ◽  
Fathollah Ommi ◽  
Vahid Esfahanian
Keyword(s):  
Diesel Engine ◽  
Soot Formation ◽  
Three Dimensional ◽  
Injection Pressure ◽  
Combustion Mechanism ◽  
Injection Timing ◽  
Post Injection ◽  
Multiple Injection ◽  
Trade Off ◽  
Di Diesel Engine

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.

An Experimental Study on Smoke Reduction Effect of Post Injection in Combination With Pilot Injection for a Diesel Engine

2013 ◽  
Vol 136 (4) ◽  
Author(s):  
Long Liu ◽  
Naoto Horibe ◽  
Tatsuya Komizo ◽  
Issei Tamura ◽  
Takuji Ishiyama
Keyword(s):  
Diesel Engine ◽  
Injection Pressure ◽  
Injection Timing ◽  
Nox Emissions ◽  
Pilot Injection ◽  
Post Injection ◽  
Spray Flames ◽  
Injection Quantity ◽  
Main Injection ◽  
Reduction Effect

With the universal utilization of the common-rail injection system in automotive diesel engines, the multistage injection strategies have become typical approaches to satisfy the increasingly stringent emission regulations, and especially the post injection has received considerable attention as an effective way for reducing the smoke emissions. Normally the post injection is applied in combination with the pilot injection to restrain the NOx emissions, smoke emissions, and combustion noise simultaneously, and the pilot injection condition affects the combustion process of the main injection and might affect the smoke reduction effect of the post injection. Thus this study aims at obtaining the post injection strategy to reduce smoke emissions in a diesel engine, where post injection is employed in combination with pilot injection. The experiments were performed using a single-cylinder diesel engine under various conditions of pilot and post injection with a constant load at an IMEP of 1.01 MPa, fixed speed of 1500 rpm, and NOx emissions concentration of 150 ± 5 ppm that was maintained by adjusting the EGR ratio. The injection pressure was set at 90 MPa at first, and then it was varied to 125 MPa to evaluate the effects of post injection on the smoke reduction in the case of higher injection pressure. The experimental results show that small post injection quantity with a short interval from the end of main injection causes less smoke emissions. And larger pilot injection quantity and later pilot injection timing lead to higher smoke emissions. And then, to explore and interpret the smoke emissions tendencies with varying pilot and post injection conditions, the experimental results of three-stage injection conditions were compared to those of two reference cases, which only included the pilot and main injection, and the interaction between main spray flames and post sprays was applied for analysis. Based on the comparative analysis, the larger smoke reduction effect of post injection was observed with the larger pilot injection quantity, while it is not greatly influenced by pilot injection timing. In addition, the smoke emissions can be reduced considerably by increasing the injection pressure, however the smoke reduction effect of post injection was attenuated. And all of these tendencies were able to be interpreted by considering the intensity variation of the interaction between main spray flames and post sprays.

scholarly journals Performance of Semi Adiabatic DI Diesel Engine with Supercharged air using Crude Jatropha Oil

2020 ◽  
Vol 9 (5) ◽  
pp. 10-16
Keyword(s):  
Developing Countries ◽  
Diesel Engine ◽  
Injection Pressure ◽  
Edible Oil ◽  
Intake Manifold ◽  
Injection Timing ◽  
High Grade ◽  
Jatropha Oil ◽  
Waste Land ◽  
Di Diesel Engine

Vegetable oils are the only fuels, can be substituted as alternative to overcome the shortage in developing countries. Using non-edible oil like crude jatropha as alternative, waste land can be effectively cultivated and employment can be improved. Experiments were Initiated on semi adiabatic diesel engine with super charging air through the intake manifold using crude jatropha oil with varied injection pressure and varied injection timing to study the performance of the engine. Tests were also conducted using diesel fuel in diesel engine and engine with high grade heat rejection combustion chamber at recommended injection timing at 270 bTDC with super charging air using crude jatropha oil. Improvement in performance was found with super charging when comparing with natural aspiration.

A review on influence of injection timing and injection pressure on DI diesel engine fuelled with low viscous fuel

2020 ◽  
Vol 33 ◽  
pp. 280-286
Author(s):  
S. Gopinath ◽  
P.K. Devan ◽  
C. Mohan ◽  
L.R. Krishna rao ◽  
P. Lokesh kumar ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Injection Pressure ◽  
Injection Timing ◽  
Di Diesel Engine
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