Influence of Post Injection on Emission Characteristics of a High-Pressure Common-Rail Diesel Engine Fueled with Biodiesel Blends

2014 ◽  
Vol 852 ◽  
pp. 808-814
Author(s):  
Di Ming Lou ◽  
Chen Chen Zhang ◽  
Zhi Yuan Hu ◽  
Pi Qiang Tan ◽  
Jian Jun Lin
Keyword(s):  
High Pressure ◽  
Diesel Engine ◽  
Common Rail ◽  
Injection Timing ◽  
Particulate Emissions ◽  
Post Injection ◽  
Biodiesel Blends ◽  
Injection Parameters ◽  
Injection Quantity ◽  
High Pressure Common Rail

An experimental study was conducted in a high-pressure common-rail diesel engine fueled with biodiesel-diesel blends (the volume ratio of biodiesel is 20%). Influences of post-injection parameters on gaseous and particulate emissions are studied. The results show that post injection timing has greater influence on particulate emissions of biodiesel engine in comparison with post injection quantity. With the delay of post injection timing, NOX emissions firstly reduce and then increase and again slightly reduce, while particulate emissions initially increase and then decrease and again soar, indicating a trade-off relationship. With the increase of post injection quantity, NOX emissions hardly change except at the low engine load, while particulate emissions increase in general. In order to improve the emission performance comprehensively, the injection parameters have to be recalibrated and split injection strategy has to be reformulated when the diesel engine is fueled with biodiesel blends.

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.

The Effects of Injection Parameters on the Performance of Common Rail Light Duty Engine Fueled with Palm Oil Biodiesel

2013 ◽  
Vol 465-466 ◽  
pp. 322-326 ◽  
Author(s):  
M. Adlan Abdullah ◽  
Farid Nasir Ani ◽  
Masjuki Hassan
Keyword(s):  
Diesel Engine ◽  
Palm Oil ◽  
Fuel Economy ◽  
Fuel Injection ◽  
Control Strategies ◽  
Engine Performance ◽  
Common Rail ◽  
Injection Timing ◽  
Injection Duration ◽  
Injection Parameters

It is in the interest of proponents of biodiesel to increase the utilization of the renewable fuel. The similarities of the methyl ester properties to diesel fuel and its miscibility proved to be an attractive advantage. It is however generally accepted that there are some performance and emissions deficit when a diesel engine is operated with biodiesel. There are research efforts to improve the diesel engine design to optimize the combustion with biodiesel. Since the common rail engines operates on flexible injection strategies, there exist an opportunity to improve engine performance and offset the fuel economy deficit by means of optimizing the engine control strategies. This approach may prove to be more practical and easily implemented. This study investigated the effects of the fuel injection parameters - rail pressure, injection duration and injection timing - on a common rail passenger car engine in terms of the fuel economy. Palm oil based biodiesel up to 30% blend in diesel was used in this study. The end of injection, (EOI), was found to be the most important parameter for affecting fuel consumption and thermal efficiency.

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