scholarly journals Numerical Investigation and Multi-Objective Optimization of Internal EGR and Post-Injection Strategies on the Combustion, Emission and Performance of a Single Cylinder, Heavy-Duty Diesel Engine

Energies ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 15
Author(s):  
Volkan Akgül ◽  
Orkun Özener ◽  
Cihan Büyük ◽  
Muammer Özkan
Keyword(s):  
Response Surfaces ◽  
Pollutant Emission ◽  
Pareto Optimum ◽  
Injection Timing ◽  
Post Injection ◽  
Heavy Duty ◽  
Single Cylinder ◽  
Multi Objective ◽  
Cycle Simulation ◽  
Main Injection

This work presents a numerical study that investigates the optimum post-injection strategy and internal exhaust gas recirculation (iEGR) application with intake valve re-opening (2IVO) aiming to optimize the brake specific nitric oxide (bsNO) and brake specific soot (bsSoot) trade-off with reasonable brake specific fuel consumption (BSFC) via 1D engine cycle simulation. For model validation, single and post-injection test results obtained from a heavy-duty single cylinder diesel research engine were used. Then, the model was modified for 2IVO application. Following the simulations performed based on Latin hypercube DoE; BSFC, bsNO and bsSoot response surfaces trained by feedforward neural network were generated as a function of the injection (start of main injection, post-injection quantity, post-injection dwell time) and iEGR (2IVO dwell) parameters. After examining the effect of each parameter on pollutant emission and engine performance, multi-objective pareto optimization was performed to obtain pareto optimum solutions in the BSFC-bsNO-bsSoot space for 8.47 bar brake mean effective pressure (BMEP) load and 1500 rpm speed condition. The results show that iEGR and post-injection can significantly reduce NO and soot emissions, respectively. The soot oxidation capability of post-injection comes out only if it is not too close to the main injection and its efficiency and effective timing are substantially affected by iEGR rate and main injection timing. It could also be inferred that by the combination of iEGR and post-injection, NO and soot could be reduced simultaneously with a reasonable increase in BSFC if start of main injection is phased properly.

scholarly journals Effect of Load on Close-Coupled Post-Injection Efficacy for Soot Reduction in an Optical Heavy-Duty Diesel Research Engine

2014 ◽  
Vol 136 (10) ◽  
Author(s):  
Jacqueline O’Connor ◽  
Mark Musculus
Keyword(s):  
High Efficiency ◽  
Fuel Injection ◽  
Operating Conditions ◽  
Optical Measurements ◽  
Injection Timing ◽  
Post Injection ◽  
Heavy Duty ◽  
Wide Range ◽  
Main Injection ◽  
Heavy Duty Diesel

The use of close-coupled post injections is an in-cylinder soot-reduction technique that has much promise for high efficiency heavy-duty diesel engines. Close-coupled post injections, short injections of fuel that occur soon after the end of the main fuel injection, have been known to reduce engine-out soot at a wide range of engine operating conditions, including variations in injection timing, exhaust gas recirculation (EGR) level, load, boost, and speed. While many studies have investigated the performance of post injections, the details of the mechanism by which soot is reduced remains unclear. In this study, we have measured the efficacy of post injections over a range of load conditions, at constant speed, boost, and rail pressure, in a heavy-duty optically-accessible research diesel engine. Here, the base load is varied by changing the main-injection duration. Measurements of engine-out soot indicate that not only does the efficacy of a post injection decrease at higher engine loads, but that the range of post-injection durations over which soot reduction is achievable is limited at higher loads. Optical measurements, including the natural luminescence of soot and planar laser-induced incandescence of soot, provide information about the spatiotemporal development of in-cylinder soot through the cycle in cases with and without post-injections. The optical results indicate that the post injection behaves similarly at different loads, but that its relative efficacy decreases due to the increase in soot resulting from longer main-injection durations.

scholarly journals Effect of Load on Close-Coupled Post-Injection Efficacy for Soot Reduction in an Optical, Heavy-Duty Diesel Research Engine

2013 ◽  
Author(s):  
Jacqueline O’Connor ◽  
Mark P. B. Musculus
Keyword(s):  
High Efficiency ◽  
Fuel Injection ◽  
Operating Conditions ◽  
Optical Measurements ◽  
Injection Timing ◽  
Post Injection ◽  
Heavy Duty ◽  
Wide Range ◽  
Main Injection ◽  
Heavy Duty Diesel

The use of close-coupled post injections of fuel is an in-cylinder soot-reduction technique that has much promise for high efficiency, heavy-duty diesel engines. Close-coupled post injections, short injections of fuel that occur soon after the end of the main fuel injection, have been known to reduce engine-out soot at a wide range of engine operating conditions, including variations in injection timing, EGR level, load, boost, and speed. While many studies have investigated the performance of post injections, the details of the mechanism by which soot is reduced remains unclear. In this study, we have measured the efficacy of post injections over a range of load conditions, at constant speed, boost, and rail pressure, in a heavy-duty, optically-accessible research diesel engine. Here, the base load is varied by changing the main-injection duration. Measurements of engine-out soot indicate that not only does the efficacy of a post injection decrease at higher engine loads, but that the range of post-injection durations over which soot reduction is achievable is limited at higher loads. Optical measurements, including natural luminescence of soot and planar laser-induced incandescence of soot, provide information about the spatio-temporal development of in-cylinder soot through the cycle in cases with and without post injections. The optical results indicate that the post injection behaves similarly at different loads, but that its relative efficacy decreases due to the increase in soot resulting from longer main-injection durations.

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.

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.

Effects of Pre-Injection on Combustion Characteristics of a Single-Cylinder Diesel Engine

2009 ◽  
Author(s):  
M. Mittal ◽  
G. Zhu ◽  
T. Stuecken ◽  
H. J. Schock
Keyword(s):  
Diesel Engine ◽  
Combustion Process ◽  
Load Condition ◽  
Combustion Characteristics ◽  
Combustion Noise ◽  
Injection Timing ◽  
Single Cylinder ◽  
Multiple Injections ◽  
Main Injection ◽  
Load Conditions

Multiple injections used for diesel engines, especially pre- and post-injections, have the potential to reduce combustion noise and emissions with improved engine performance. This paper outlines the combustion characteristics of a single-cylinder diesel engine with multiple injections. The effects of pre-injection (multi-injection) on combustion characteristics are presented in a single-cylinder diesel engine at different engine speeds and load conditions. A common rail fuel system with a solenoid injector, driven by a peak and hold circuit, is used in this work. This enables us to control the number of injections, fuel injection timing and duration, and the fuel rail pressure that can be used to optimize the engine combustion process (e.g., eliminate engine knock). Mass fraction burned and burn durations are determined by analyzing the measured in-cylinder pressure data. Results are compared with the cases when no pre-injection was used, i.e. only main injection, at the same engine speeds and load conditions. In each study, different cases are considered with the variation in main injection timing. It is found that at full-load condition and lower engine speeds pre-injection is an effective method to alter the engine burn rate and hence to eliminate knock.

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.

Comparison study between mixer and liquefied petroleum injection system fuel supply methods in a heavy-duty single cylinder engine

2005 ◽  
Vol 219 (9) ◽  
pp. 1119-1123 ◽  
Author(s):  
Gyeung Ho Choi ◽  
Yon Jong Chung ◽  
Sung Bin Han
Keyword(s):  
Injection System ◽  
Intake Manifold ◽  
Injection Timing ◽  
Liquefied Petroleum Gas ◽  
Heavy Duty ◽  
Single Cylinder ◽  
Emission Properties ◽  
Single Cylinder Engine ◽  
Liquid Phases ◽  
Timing Data

The purpose of this study is to analyse the combustion and emission characteristics of a heavy-duty single cylinder engine (HDSCE) with a mixer and a liquefied petroleum injection (LPi) system. The mixer and LPi systems provide liquefied petroleum gas (LPG) in vapour and liquid phases throughout the intake manifold. Sensors such as the crankshaft position sensor (CPS) and Hall sensor supply spark and injection timing data to the ignition controller. An HDSCE runs at an engine speed of 800–1400 r/min, a compression ratio (CR) of 8, and a relative air-fuel ratio (Λ) value of 0.8–1.3. The major conclusions of this work include: LPi and mixer systems exhibit similar brake specific fuel consumption (b.s.f.c.) levels of 275g/kWh. Fuel efficiencies of LPi and mixer methods are almost identical. All these methods exhibit generally similar CO emission properties, and LPi wide-open throttle (WOT) and mixer WOT methods exhibit similar NOx emission properties.

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.

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