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.

Optimization of operating parameters of an off-road automotive diesel engine running at highway drive conditions using Response Surface Methodology

2020 ◽  
pp. 1-48 ◽  
Author(s):  
Vinod Babu Marri ◽  
K. Madhu Murthy ◽  
G. Amba Prasad Rao
Keyword(s):  
Response Surface Methodology ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Operating Parameters ◽  
Injection Timing ◽  
Boost Pressure ◽  
Pilot Injection ◽  
Injection Quantity ◽  
Main Injection ◽  
Fuel Injection Pressure

Abstract The typical tradeoff between the two major emissions from compression ignition (CI) engines, smoke and oxides of nitrogen, is the unresolved challenge to the researchers. Techniques like engine downsizing, lowering intake oxygen concentration, multiple injections, use of retarded injection timings and higher injection pressures, etc. are widely employed for the alleviation of these harmful emissions. The influence of variation of fuel injection pressure (FIP), boost pressure, pilot injection timing (PIT), pilot injection quantity (PIQ) and main injection timing (MIT) are experimentally investigated in the present work. Mahindra mHawk four-cylinder diesel engine with provisions of a variable-geometry turbocharger (VGT), exhaust gas recirculation (EGR), and common-rail direct injection (CRDi) is chosen for the experimentation. Test runs are conducted at 1750 rpm and 80.3 N.m (4.6 bar bmep) corresponding to highway drive conditions, using 10 % EGR. Response surface methodology is employed for the design of experiments and to analyze the experimental data. Multi-objective response optimization is carried out to optimize engine-operating parameters that give desired performance and engine-out emissions. Confirmatory tests are conducted at design conditions to validate the results predicted by the model. This study reveals that the optimum performance and emission characteristics could be obtained using 120 kPa boost pressure; 61.1 MPa fuel injection pressure; 11.5 % pilot injection quantity with pilot injection at 332 °CA and main injection at 359 °CA.

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 Investigation of the Effects of Common-Rail Injection System Parameters on Emissions and Performance in a High-Speed Direct-Injection Diesel Engine

1999 ◽  
Vol 123 (1) ◽  
pp. 167-174 ◽  
Author(s):  
P. J. Tennison ◽  
R. Reitz
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Direct Injection ◽  
Injection Pressure ◽  
Injection System ◽  
Injection Timing ◽  
Pilot Injection ◽  
Common Rail Injection System ◽  
And Performance ◽  
Emissions And Performance

An investigation of the effect of injection parameters on emissions and performance in an automotive diesel engine was conducted. A high-pressure common-rail injection system was used with a dual-guided valve covered orifice nozzle tip. The engine was a four-valve single cylinder high-speed direct-injection diesel engine with a displacement of approximately 12 liter and simulated turbocharging. The engine experiments were conducted at full load and 1004 and 1757 rev/min, and the effects of injection pressure, multiple injections (single vs pilot with main), and pilot injection timing on emissions and performance were studied. Increasing the injection pressure from 600 to 800 bar reduced the smoke emissions by over 50 percent at retarded injection timings with no penalty in oxides of nitrogen NOx or brake specific fuel consumption (BSFC). Pilot injection cases exhibited slightly higher smoke levels than single injection cases but had similar NOx levels, while the single injection cases exhibited slightly better BSFC. The start-of-injection (SOI) of the pilot was varied while holding the main SOI constant and the effect on emissions was found to be small compared to changes resulting from varying the main injection timing. Interestingly, the point of autoignition of the pilot was found to occur at a nearly constant crank angle regardless of pilot injection timing (for early injection timings) indicating that the ignition delay of the pilot is a chemical delay and not a physical (mixing) one. As the pilot timing was advanced the mixture became overmixed, and an increase of over 50 percent in the unburned hydrocarbon emissions was observed at the most advanced pilot injection timing.

scholarly journals Assessment on the consequences of injection strategies on combustion process and particle size distributions in Euro VI medium-duty diesel engine

2019 ◽  
Vol 21 (4) ◽  
pp. 683-697 ◽  
Author(s):  
Vicente Bermúdez ◽  
Antonio García ◽  
David Villalta ◽  
Lian Soto
Keyword(s):  
Particle Size ◽  
Diesel Engine ◽  
Size Distribution ◽  
Particle Concentration ◽  
Combustion Process ◽  
Injection Pressure ◽  
Injection Timing ◽  
Injection Parameters ◽  
Main Injection ◽  
Injection Strategies

Although there are already several works where the influence of injection parameters on exhaust emissions, and specifically on particulate matter emissions, in diesel engines has been evaluated, the diversity in the results that can be found in the literature indicates the need to carry out new experiments that can provide more information about the influence of these parameters on modern diesel engines. This study intends to be placed within this scientific framework, hence a parametric study was carried out based on the independent modification of the main injection timing and the injection pressure with respect to the nominal conditions of a new Euro VI direct injection diesel engine. Four steady-state operation points of the engine map were chosen: 25% load and 950 r/min, 50% load and 1500 r/min, 75% load and 2000 r/min and 100% load and 2200 r/min, where in each of these operation points, the variations of the injection parameters in the study on the combustion process and its consequent impact on the particle size distribution, including an analysis of the geometric mean diameter values, were evaluated. The results showed that the different injection strategies adopted, despite not significantly affecting the engine efficiency, did cause a significant impact on particle number emissions. At the low load operation, the size distribution showed a bimodal structure, and as the main injection timing was delayed and the injection pressure was decreased, the nucleation-mode particle concentration decreased, while the accumulation-mode particle concentration increased. In addition, at medium load, the nucleation-mode particle emission decreased considerably while the accumulation-mode particle emission increased, and this increase was much greater with the main injection timing delay and the injection pressure reduction. Similar behavior was observed at high load, but with a much more prominent pattern.

Study on the Mechanism of Soot Reduction by Multi-Injection Coupled with EGR

2013 ◽  
Vol 805-806 ◽  
pp. 1759-1762 ◽  
Author(s):  
Jing Luo ◽  
Hai Feng Liu
Keyword(s):  
Oxidation Rate ◽  
Positive Impact ◽  
Soot Oxidation ◽  
Injection Timing ◽  
Pilot Injection ◽  
Soot Emission ◽  
Post Injection ◽  
Multiple Injections ◽  
Injection Quantity ◽  
Heavy Duty Diesel

The effects of multiple injections coupled with medium EGR (25% - 30%) on heavy duty diesel engine were investigated. Injection timing and mass were adjusted with different injection strategies (main-post and pilot-main) to study the influence of these parameters on combustion and emissions. The mechanism of soot emission reduction was discussed. Results indicate that, at fixed total injection quantity and EGR rate, NOx is reduced, while soot is decreased followed by an increasing with increasing post injection quantity; NOx nearly kept constant and soot declined before rising with lager main-post interval. Optimum post injection could accelerate soot oxidation rate. Pilot injection has no positive impact on NOx, while soot decreases with less pilot fuel mass and lager pilot-main interval. Optimum pilot injection could be beneficial for a better mixture property. The acceleration of soot oxidation rate is the basic reason of soot emission reducing by multiple injections.

Numerical investigation on the impact of multiple injection strategies and spray included angles on combustion and emissions in a marine diesel engine

2021 ◽  
pp. 095440702110694
Author(s):  
Shiru Kong ◽  
Changpu Zhao ◽  
Zhishang Bian ◽  
Yujie Cai
Keyword(s):  
Injection Timing ◽  
Pilot Injection ◽  
Post Injection ◽  
Simultaneous Reduction ◽  
Included Angle ◽  
Injection Duration ◽  
Marine Diesel ◽  
Main Injection ◽  
The Impact ◽  
Injection Strategies

The computational fluid dynamical software AVL-FIRE code was used for investigating the impact of multiply injection strategies and spray included angles on combustion and emissions in a marine diesel engine. The fuel injection parameters of spray included angle and pilot injection timing with pilot-main injection, as well as post injection ratio and post injection duration angle with pilot-main-post injection, were all investigated and optimized. The results indicate that retarding pilot injection timing with pilot-main injection declines high temperature region, resulting in a notable reduction in NOx emissions. Since fuel evaporation and burn are hampered by long spray penetration due to low temperature and pressure with pilot injection, a suitable spray included angle are used to offer more efficient air-fuel mixing process. A wider spray included angle simultaneously reduces soot emission and indicated specific fuel consumption (ISFC). Post injection fuel exerts impact on combustion process by causing a great disturbance to flow field during post combustion. Increasing post injection ratio from 4% to 10% at a small post injection duration angle great emission performance is achieved by simultaneous reduction in NOx and soot emissions while only using a slight consumption of ISFC. To summarize, the defeat of traditional NOx-soot trade-off occurs as both NOx and soot emissions are decreased with optimized multiple injection strategy and spray included angle. Particularly, there are respectively four cases with pilot-main injection and two cases with pilot-main-post injection, that achieve simultaneous reduction in NOx emissions, soot emission, and ISFC, compared to the prototype.

Experimental Investigation of Thermal Load in High Speed Direct Injection Diesel Engine Under the Control of Various Engine Performance Parameters

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
Jeonghoon Lee
Keyword(s):  
Diesel Engine ◽  
Thermal Load ◽  
High Speed ◽  
Direct Injection ◽  
Injection Timing ◽  
Pilot Injection ◽  
Performance Parameters ◽  
Full Load ◽  
Main Injection ◽  
Vibration Noise

Multiple injection strategies are being widely utilized to reduce the vibration, noise, and particle emission in diesel engines. A considerable amount of research related to attempts to increase the maximum power and to reduce vibration, noise, and particulate matters has been done. However, investigations of various performance parameters in terms of the thermal load in high speed direct injection engines are rarely to be found despite the fact that the relationship between these parameters and the reliability of the engine is important for mass production. Hence, the thermal load imposed on the cylinder head and cylinder block of a four-cylinder diesel engine was investigated under the most severe test conditions, at the rated speed and with a full load, by changing the performance parameters such as the main injection timing, the fuel pressure in the common rail, the boost pressure, the exhaust gas recirculation, the fuel quantity of the pilot injection, the timing of the pilot injection, the fuel quantity of the postinjection, and the timing of postinjection. Experimental results showed that the main injection timing among other parameters was the parameter that influenced the thermal load most at the rated engine speed and under a full load condition.

Comparison of Ultra-High Rail Pressures and Postinjections for Soot Reduction With Massive Exhaust Gas Recirculation

2019 ◽  
Vol 141 (9) ◽  
Author(s):  
Ryan M. Ogren ◽  
Song-Charng Kong
Keyword(s):  
Injection Pressure ◽  
Exhaust Gas Recirculation ◽  
Injection Timing ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Engine Fuel ◽  
Post Injection ◽  
High Injection ◽  
Gas Recirculation ◽  
Injection Pressures

In this study, the application of ultra-high fuel injection pressure (up to 300 MPa) is compared with that of a post injection strategy for the reduction of soot at medium load conditions with exhaust gas recirculation (EGR) rates greater than 40%. Emissions were predominantly studied at the engine's maximum brake torque speed of 1600 rpm. A 4.5-L, four-cylinder diesel engine with series turbochargers and a high-pressure EGR loop was used for all tests. Results indicate that, ultra-high injection pressures may not have large effects on hydrocarbons (HC) or CO emissions. Small soot reductions were achieved at the expense of increased NOx emissions. Post injections resulted in larger soot reductions for a small increase in NOx while allowing lower fuel pressures to be utilized. The increase in NOx emissions with a post injection was observed to be comparatively less at increased engine speeds. For operation at high EGR, post injections were observed to be more effective at reducing soot than ultra-high injection pressures. Both injection pressure and post injections were observed to have small to negligible effects on engine fuel consumption, leaving EGR and injection timing as the primary efficiency drivers at the conditions studied.

scholarly journals Experimental Study of Injection Parameters on the Performance of a Diesel Engine with Fischer–Tropsch Fuel Synthesized from Coal

Energies ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 3280 ◽  
Author(s):  
Jinhong Shi ◽  
Tie Wang ◽  
Zhen Zhao ◽  
Tiantian Yang ◽  
Zhengwu Zhang
Keyword(s):  
Diesel Engine ◽  
Combustion Process ◽  
Injection Pressure ◽  
Injection Timing ◽  
Nox Emissions ◽  
Cylinder Pressure ◽  
Fischer Tropsch ◽  
Ignition Point ◽  
Injection Parameters ◽  
Combustion Emissions

Experimental research was conducted on a turbo-charged, inter-cooling and common-rail diesel engine with Fischer–Tropsch fuel synthesized from Coal-to-liquid (CTL), in order to investigate the influence of different injection parameters on the combustion, emissions and efficiency characteristics of the engine. The results showed that the ignition point was advanced, the in-cylinder pressure and heat release rate increased as the injection timing advanced and the injection pressure increased. By comparing the peak in-cylinder pressure of 100 cycles for one sample, it was found that the coefficient variation (COV) remained under 2% throughout the tests and the combustion process remained stable. NOx emissions decreased with delayed injection timing and lower injection pressure. In contrast to NOXNOx emissions, soot emissions were almost zero when the injection pressure was up to 143.5 MPa. The indicated thermal efficiency (ITE) showed no obvious change with different injection parameters, and remained under 40% in all the tests.

A Study on a Passenger Car Diesel Engine Fueled with Butanol-Diesel Blend under Typical Operating Condition

2012 ◽  
Vol 190-191 ◽  
pp. 1345-1350
Author(s):  
Ting Bo Zhou ◽  
Zhi Yu Han ◽  
Zheng Chen ◽  
Biao Du ◽  
Yun Liu
Keyword(s):  
Diesel Engine ◽  
Injection Timing ◽  
Passenger Car ◽  
Blend Ratio ◽  
Operating Condition ◽  
Injection Quantity ◽  
Combustion Phase ◽  
Main Injection ◽  
Typical Operating Condition ◽  
Burn Rate

The effects of butanol-diesel blending ratio, injecting timing and pilot injection quantity on combustion and emissions were experimentally investigated for a passenger car diesel engine. The results showed that under the typical operating condition of 2000r/min engine speed and 0.2MPa BMEP engine load, the engine’s combustion phase retarded, the peak combustion pressure and maximum in-cylinder mean temperature decreasing with the delay of the main injection timing using both the neat diesel and diesel-butanol blends. And the engine smoke level increased, while the NOx and CO emissions decreased. However, at the same main injection timing, with the increase of the butanol in the blends, the ignition delay of the combustion prolonged, the burn rate and brake specific fuel consumption increased, NOx and soot emissions decreased, and HC and CO emissions increased, while the peak in-cylinder pressure was slightly influenced. The results of this study indicate that the selection of the butanol-diesel blend ratio and injection timing should consider the engineering balances among the engine’s fuel economy and emissions.

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