Effect of post-injection strategies on regulated and unregulated harmful emissions from a heavy-duty diesel engine

2020 ◽  
pp. 146808742098091
Author(s):  
Sheikh Muhammad Farhan ◽  
Wang Pan ◽  
Wu Yan ◽  
Yi Jing ◽  
Lei Lili
Keyword(s):  
Diesel Engine ◽  
Injection Technique ◽  
Nox Emissions ◽  
Post Injection ◽  
Heavy Duty ◽  
Fuel Mass ◽  
Start Of Injection ◽  
Main Injection ◽  
Unregulated Emissions ◽  
Injection Strategies

An experimental study was carried out to analyze the influence of different post-injection strategies on the regulated and unregulated emissions from a heavy-duty compression ignition (CI) diesel engine. FTIR (Fourier transform infrared spectroscopy) was used to measure and analyze the exhaust emissions which include regulated such as NOx, soot, and unregulated emissions including acetaldehyde, formaldehyde, methane, ethane, propane, ethylene, propylene, and ethyne. Experimental results manifested that the post-injection technique can notably minimize the regulated and unregulated emissions as compared to a single main injection. Under different post-injection conditions, a trade-off relation was also found between soot and NOx emissions. In soot mitigation, the start of injection (SOI) at 40° crank angle (CA) incorporate with 5–15 mg post-injection fuel mass was proved very effective and about 26% lower soot emissions were recorded than single main injection. At SOI 20°CA, with 15 mg post-injection fuel mass, a reduction in the NOx emissions was observed up to 20% and in THC up to 60%. Unregulated emissions (other than formaldehyde and acetaldehyde) were found lower with 5, 10, and 15 mg post-injection fuel mass at 20, 40, 100, and 120°CA but increased at SOI of 60°CA than single main injection. In addition, light HCs, and THC emissions at SOI 60°CA were found to increase which could be beneficial for after-treatment devices.

scholarly journals Effects of multiple injections on combustion and emissions in a heavy-duty diesel engine at high load and low speed

2020 ◽  
Vol 12 (12) ◽  
pp. 168781402098462
Author(s):  
Yingying Lu ◽  
Yize Liu
Keyword(s):  
Diesel Engine ◽  
Single Injection ◽  
High Load ◽  
Post Injection ◽  
Heavy Duty ◽  
Low Speed ◽  
Multiple Injections ◽  
Heavy Duty Diesel Engine ◽  
Main Injection ◽  
Heavy Duty Diesel

Advanced multiple injection strategies have been suggested for compression ignition engines in order to meet the increasingly stringent emission regulations. Experiments and simulations were used to study effects of the main-injection mode (times), the post-injection proportion, and timing on combustion and emissions in a heavy-duty diesel engine at high load and constant low speed. The results reveal the following. The NOx emissions of 1main+1post, 2main+1post, and 3main+1post injections are all lower than those of single injection; the higher the number of main-injection pluses, the lower the NOx emissions. Enough main-post injection interval is needed to ensure post and main injections are relatively independent to entrain more fresh air to decrease the soot. Over-retarded post-injection timing tends to increase the soot due to the lower in-cylinder temperature. The combined effects of formation and oxidation determine the final soot. To gain the best trade-off of NOx and soot, compared with single injection, for the three multiple injections, the lowest soot emissions are gained at post-injection proportions of 15% and post-injection timings of 25°, 30°, and 35° CA ATDC, with soot reductions of 26.7%, −34.5%, and −112.8%, and NOx reductions of 5.88%, 21.2%, and 40.3%, respectively, for 1main+1post, 2main+1post, and 3main+1post injections.

Impact of post-injection strategies on combustion and unregulated emissions during different loads in an HSDI diesel engine

Fuel ◽  
2020 ◽  
Vol 267 ◽  
pp. 117256 ◽  
Author(s):  
Sheikh Muhammad Farhan ◽  
Wang Pan ◽  
Wu Yan ◽  
Yi Jing ◽  
Lei Lili
Keyword(s):  
Diesel Engine ◽  
Post Injection ◽  
Hsdi Diesel Engine ◽  
Unregulated Emissions ◽  
Injection Strategies

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.

A CFD Study on Heavy Duty DI Diesel Engine to Achieve Ultra-Low Emissions

2010 ◽  
Author(s):  
M. Yilmaz ◽  
H. Koten ◽  
M. Zafer Gul
Keyword(s):  
Diesel Engine ◽  
Cfd Simulation ◽  
Combustion Engine ◽  
Direct Injection ◽  
Spray Angle ◽  
Combustion Model ◽  
Multiphase Model ◽  
Heavy Duty ◽  
Start Of Injection ◽  
Main Injection

Nowadays, automotive industries focused on clean diesel combustion in their combustion processes are investigated for their potential to achieve near zero particulate and NOx (Nitrogen oxides) emissions. Their main disadvantages are increased level of unburned hydrocarbons (HC) and carbon monoxide (CO) emissions, combustion control at high load, power output and limited operating range. The simulation of the air flow, spray and combustion in an internal combustion engine were prepared for a single cylinder of a nine-liter, six cylinder diesel engine. Many times the geometry is complex because moving pistons and valves are involved, which makes it difficult to generate structured mesh. In-cylinder spray-air motion interaction, a Lagrangian multiphase model has been applied in a heavy-duty CI engine under direct injection conditions. A comprehensive model for atomization of liquid sprays under high injection pressures has been employed. Three dimensional CFD calculations of the intake, compression and power strokes have been carried out with different spray angle, spray profile and start of injection. A new combustion model ECFM-3Z (Extended Coherent Flame Model) developed at IFP is used for combustion modeling. Finally, a calculation on an engine configuration with compression, spray injection and combustion in a direct injection Diesel engine is presented. In this study, exhaust emissions, and particularly the emission of NOx, CO and soot derived from premixed combustion are investigated, and the relationship between combustion and emission characteristics are showed. The calculated CFD simulation in different combustion cases was compared. The cases were prepared by changing the parameters: start of injection, spray angle and spray profile. Modeling of combustion proposed in the present study can be outlined as follows. NOx concentration is decreased by combustion of a over lean-mixture modeled by the pre-injection. Most of pre-mixture is combusted by main-injection, and therefore the amount of pre-injection and main-injection come into prominence. The results are greatly in agreement qualitatively with the previous experimental and computational studies in the literature.

scholarly journals Effects of Different Injection Strategies on Combustion and Emission Characteristics of Diesel Engine Fueled with Dual Fuel

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1300
Author(s):  
Jianbin Luo ◽  
Zhonghang Liu ◽  
Jie Wang ◽  
Heyang Chen ◽  
Zhiqing Zhang ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Natural Gas ◽  
Nox Emission ◽  
Dual Fuel ◽  
Emission Characteristics ◽  
Post Injection ◽  
Mixing Ratio ◽  
Gas Mixing ◽  
Main Injection ◽  
Injection Strategies

In this work, an effective numerical simulation method was developed and used to analyze the effects of natural gas mixing ratio and pilot-main injection, main-post injection, and pilot-main-post injection strategies on the combustion and emission characteristics of diesel engine fueled with dual fuel. Firstly, the one-dimensional calculation model and three-dimensional CFD model of the engine were established by AVL-BOOST and AVL-Fire, respectively. In addition, the simplified chemical kinetics mechanism was adopted, which could accurately calculate the combustion and emission characteristics of the engine. The results show that the cylinder pressure and heat release rate decrease with the increase of the natural gas mixing ratio and the NOx emission is reduced. When the NG mixing ratio is 50%, the NOx and CO emission are reduced by 47% and 45%, respectively. When the SODI3 is 24 °CA ATDC, the NOx emission is reduced by 29.6%. In addition, with suitable pilot-main injection and pilot-main-post injection strategies, the combustion in the cylinder can be improved and the trade-off relationship between NOx and soot can be relaxed. Thus, the proper main-post injection strategy can improve the combustion and emission characteristics, especially the reduction in the NOx and CO emissions.

scholarly journals Detailed Injection Strategy Analysis of a Heavy-Duty Diesel Engine Running on Rape Methyl Ester

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3717
Author(s):  
Nikita Zuev ◽  
Andrey Kozlov ◽  
Alexey Terenchenko ◽  
Kirill Karpukhin ◽  
Ulugbek Azimov
Keyword(s):  
Fuel Injection ◽  
Combustion Process ◽  
Pressure Rise ◽  
Base Case ◽  
Biodiesel Fuel ◽  
Pilot Injection ◽  
Post Injection ◽  
Heavy Duty ◽  
Injection Strategy ◽  
Fuel Mass

Using biodiesel fuel in diesel engines for heavy-duty transport is important to meet the stringent emission regulations. Biodiesel is an oxygenated fuel and its physical and chemical properties are close to diesel fuel, yet there is still a need to analyze and tune the fuel injection parameters to optimize the combustion process and emissions. A four-injections strategy was used: two pilots, one main and one post injection. A highly advanced SOI decreases the NOx and the compression work but makes the combustion process less efficient. The pilot injection fuel mass influences the combustion only at injection close to the top dead center during the compression stroke. The post injection has no influence on the compression work, only on the emissions and the indicated work. An optimal injection strategy was found to be: pilot SOI 19.2 CAD BTDC, pilot injection fuel mass 25.4%; main SOI 3.7 CAD BTDC, main injection fuel mass 67.3% mg; post SOI 2 CAD ATDC, post injection fuel mass 7.3% (the injection fuel mass is given as a percentage of the total fuel mass injected). This allows the indicated work near the base case level to be maintained, the pressure rise rate to decrease by 20% and NOx emissions to decrease by 10%, but leads to a 5% increase in PM emissions.

Two-Stroke Marine Diesel Engine Variable Injection Timing System Performance Evaluation and Optimum Setting for Minimum Fuel Consumption at Acceptable NOx Levels

2014 ◽  
Author(s):  
Dimitrios T. Hountalas ◽  
Spiridon Raptotasios ◽  
Antonis Antonopoulos ◽  
Stavros Daniolos ◽  
Iosif Dolaptzis ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Engine Performance ◽  
Operating Conditions ◽  
Specific Fuel Consumption ◽  
Injection Timing ◽  
Nox Emissions ◽  
Pressure Measurements ◽  
Cylinder Pressure ◽  
Start Of Injection

Currently the most promising solution for marine propulsion is the two-stroke low-speed diesel engine. Start of Injection (SOI) is of significant importance for these engines due to its effect on firing pressure and specific fuel consumption. Therefore these engines are usually equipped with Variable Injection Timing (VIT) systems for variation of SOI with load. Proper operation of these systems is essential for both safe engine operation and performance since they are also used to control peak firing pressure. However, it is rather difficult to evaluate the operation of VIT system and determine the required rack settings for a specific SOI angle without using experimental techniques, which are extremely expensive and time consuming. For this reason in the present work it is examined the use of on-board monitoring and diagnosis techniques to overcome this difficulty. The application is conducted on a commercial vessel equipped with a two-stroke engine from which cylinder pressure measurements were acquired. From the processing of measurements acquired at various operating conditions it is determined the relation between VIT rack position and start of injection angle. This is used to evaluate the VIT system condition and determine the required settings to achieve the desired SOI angle. After VIT system tuning, new measurements were acquired from the processing of which results were derived for various operating parameters, i.e. brake power, specific fuel consumption, heat release rate, start of combustion etc. From the comparative evaluation of results before and after VIT adjustment it is revealed an improvement of specific fuel consumption while firing pressure remains within limits. It is thus revealed that the proposed method has the potential to overcome the disadvantages of purely experimental trial and error methods and that its use can result to fuel saving with minimum effort and time. To evaluate the corresponding effect on NOx emissions, as required by Marpol Annex-VI regulation a theoretical investigation is conducted using a multi-zone combustion model. Shop-test and NOx-file data are used to evaluate its ability to predict engine performance and NOx emissions before conducting the investigation. Moreover, the results derived from the on-board cylinder pressure measurements, after VIT system tuning, are used to evaluate the model’s ability to predict the effect of SOI variation on engine performance. Then the simulation model is applied to estimate the impact of SOI advance on NOx emissions. As revealed NOx emissions remain within limits despite the SOI variation (increase).

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