scholarly journals Research of Post Injection Strategy of an EGR Diesel Engine to Improve Combustion and Particulate Emissions Performance: Application on the Transient Operation

Symmetry ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2002
Author(s):  
Shuang Feng ◽  
Wei Hong ◽  
Yongming Yao ◽  
Tian You
Keyword(s):  
Diesel Engine ◽  
Particle Number ◽  
Number Concentration ◽  
Particulate Emissions ◽  
Nox Emissions ◽  
Post Injection ◽  
Transient Operation ◽  
Mobile Source ◽  
Injection Strategy ◽  
Loading Process

Mobile source emissions have already accounted for a large proportion of environmental pollution, which seriously affect the symmetric characteristics of atmosphere, and automobile emissions have extremely serious deterioration of emissions under transient operation, especially particulate emissions. These factors exacerbate the asymmetry of the environment. So, the paper reports an experiment about the improvement of post injection strategy on combustion, regulated emissions (HC, CO, and NOx), and particle number emissions especially the emissions of different size particles in the transient process of an EGR diesel engine, meanwhile, the effects of post injection on the combustion of mixture are further analyzed by numerical simulation method. The test speed was 1600 r/min, and the torque increased from 5% of the maximum torque to 100%. The results indicated that the shorter the instantaneous loading time, the more severe the deterioration of particulate emissions, HC and CO emissions, but loading time has little effect on NOx emissions. The particles with the size range of 50–100 nm, 23–50 nm, and >100 nm are greatly affected by the loading process and post injection. In comparison, it has little effect on ultrafine particles with particle size of 15–23 nm and <15 nm. With the amount of post injection increased, the in-cylinder disturbance increased, and the oxygen-rich area in cylinder increased, the particle number concentration first decreased and then slightly increased. When the amount of post injection fuel is 2 mg and the main-post injection interval is 2000 us, the effects of suppressing particulate emissions are the best, for the 50–100 nm and >100 nm particles, the peak number concentration can be reduced by 25% and 50%, respectively. Due to the turbo charging lag, the peak of NOx emissions during the unloading process were slightly larger than the loading process.

Effect of Fuel Injection Strategy on DPF Regeneration in Single Cylinder Diesel Engine

2015 ◽  
Author(s):  
Sungjun Yoon ◽  
Hongsuk Kim ◽  
Daesik Kim ◽  
Sungwook Park
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Operating Conditions ◽  
Experimental Results ◽  
Exhaust Gas ◽  
Post Injection ◽  
Gas Temperature ◽  
Injection Strategy ◽  
Dpf Regeneration ◽  
Exhaust Gas Temperature

Stringent emission regulations (e.g., Euro-6) force automotive manufacturers to equip DPF (diesel particulate filter) on diesel cars. Generally, post injection is used as a method to regenerate DPF. However, it is known that post injection deteriorates specific fuel consumption and causes oil dilution for some operating conditions. Thus, an injection strategy for regeneration becomes one of key technologies for diesel powertrain equipped with a DPF. This paper presents correlations between fuel injection strategy and exhaust gas temperature for DPF regeneration. Experimental apparatus consists of a single cylinder diesel engine, a DC dynamometer, an emission test bench, and an engine control system. In the present study, post injection timing covers from 40 deg aTDC to 110 deg aTDC and double post injection was considered. In addition, effects of injection pressures were investigated. The engine load was varied from low-load to mid-load and fuel amount of post injection was increased up to 10mg/stk. Oil dilution during fuel injection and combustion processes were estimated by diesel loss measured by comparing two global equivalences ratios; one is measured from Lambda sensor installed at exhaust port, the other one is estimated from intake air mass and injected fuel mass. In the present study, the differences in global equivalence ratios were mainly caused from oil dilution during post injection. The experimental results of the present study suggest an optimal engine operating conditions including fuel injection strategy to get appropriate exhaust gas temperature for DPF regeneration. Experimental results of exhaust gas temperature distributions for various engine operating conditions were summarized. In addition, it was revealed that amounts of oil dilution were reduced by splitting post injection (i.e., double post injection). Effects of injection pressure on exhaust gas temperature were dependent on combustion phasing and 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.

scholarly journals Oxygen-Enriched Diesel Engine Performance: A Comparison of Analytical and Experimental Results

1991 ◽  
Vol 113 (3) ◽  
pp. 365-369 ◽  
Author(s):  
R. R. Sekar ◽  
W. W. Marr ◽  
D. N. Assanis ◽  
R. L. Cole ◽  
T. J. Marciniak ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Experimental Studies ◽  
Engine Performance ◽  
Oxygen Enrichment ◽  
Published Data ◽  
Particulate Emissions ◽  
Lower Grade ◽  
Nox Emissions ◽  
Release Rates

Use of oxygen-enriched combustion air in diesel engines can lead to significant improvements in power density, as well as reductions in particulate emissions, but at the expense of higher NOx emissions. Oxygen enrichment would also lead to lower ignition delays and the opportunity to burn lower grade fuels. Analytical and experimental studies are being conducted in parallel to establish the optimal combination of oxygen level and diesel fuel properties. In this paper, cylinder pressure data acquired on a single-cylinder engine are used to generate heat release rates for operation under various oxygen contents. These derived heat release rates are in turn used to improve the combustion correlation—and thus the prediction capability—of the simulation code. It is shown that simulated and measured cylinder pressures and other performance parameters are in good agreement. The improved simulation can provide sufficiently accurate predictions of trends and magnitudes to be useful in parametric studies assessing the effects of oxygen enrichment and water injection on diesel engine performance. Measured ignition delays, NOx emissions, and particulate emissions are also compared with previously published data. The measured ignition delays are slightly lower than previously reported. Particulate emissions measured in this series of tests are significantly lower than previously reported.

Exhaust Emissions of an Off-Road Diesel Engine Driven With a Blend of Diesel Fuel and Mustard Seed Oil

2003 ◽  
Author(s):  
Seppo A. Niemi ◽  
Juha M. Tyrva¨inen ◽  
Mika J. Laure´n ◽  
Va¨ino¨ O. K. Laiho
Keyword(s):  
Diesel Engine ◽  
Diesel Fuel ◽  
Seed Oil ◽  
Particle Number ◽  
Exhaust Emissions ◽  
Mustard Seed ◽  
Injection Timing ◽  
Nox Emissions ◽  
Fuel Blend ◽  
Full Load

In the near future, crude oil based fuels must little by little be replaced by biofuels both in the region of the European Union (EU) and in the United States. Bearing this in mind, a Finnish-made off-road diesel engine was tested with a biofuel-diesel fuel blend in the Internal Combustion Engine (ICE) Laboratory of Turku Polytechnic, Finland. The biofuel was cold-pressed mustard seed oil (MSO). The engine operation, performance and exhaust emissions were investigated using a blend of 30 mass-% MSO and 70 mass-% diesel fuel oil (DFO). The injection timing of the engine was retarded considerably in order to reduce NOx emissions drastically. The main target was then to find out, whether the blended oxygen containing MSO would speed up the combustion so that the particulate matter (PM) emissions would remain unchanged or even decrease despite the injection retardation. As secondary tasks of the study, the NOx readings of the CLD and FTIR analyzers were compared, and exhaust contents of unregulated compounds were determined. Retarding the injection timing resulted in a significant decrease of NOx emissions, but in an increase in smoke, as expected. At retarded timing, the NOx emissions remained almost unchanged, but the amount of smoke decreased when the engine was run with the fuel blend instead of DFO. At retarded timing at rated speed, the number of ultra-fine particles decreased, but the amount of large particles increased with DFO at full load. At 10% load, however, the particle number increased in the entire particle size range due to retardation. At both loads, the use of the fuel blend slightly reduced larger particles, whereas the number of small particles somewhat increased. At full load at an intermediate speed of 1500 rpm, the PM results were very similar to those obtained at rated speed. At 10% load with DFO, however, the injection retardation led to a higher number of larger particles, the smaller particles being at almost an unchanged level. With the fuel blend, the particle number was now higher within almost the whole particle diameter range than with DFO. Considerably higher NO2 contents were usually detected with FTIR than with CLD. The shape of the NOx result curves were rather similar independent of which one of the analyzers was used for measurements. The NOx contents were, however, generally some ten ppms higher with FTIR. The exhaust contents of unregulated compounds were usually low.

Characteristics of Particulate Matter about Emissions in a Heavy-Duty Diesel Engine with Biodiesel Blends

2014 ◽  
Vol 852 ◽  
pp. 802-807
Author(s):  
Di Ming Lou ◽  
Tian Yu Shen ◽  
Yi Zhou ◽  
Zhi Yuan Hu ◽  
Pi Qiang Tan ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Particle Number ◽  
Number Concentration ◽  
Particle Number Concentration ◽  
Heavy Duty ◽  
Full Load ◽  
Nucleation Mode ◽  
Heavy Duty Diesel Engine ◽  
Load Characteristics ◽  
Heavy Duty Diesel

A China-V Heavy-duty diesel engine fueled with blends of 5%, 10%, 20%, 50% waste cooking oil biodiesel and diesel (marked separately BD5, BD10, BD20, BD50), pure biodiesel (BD100) and pure diesel (D100), was tested on full load speed characteristics and 1400 r/min and 2200 r/min load characteristics to study influence of biodiesel fuel and engine conditions on particle size distributions and particle number concentration. The results show that when fueled with blends containing less than 50% biodiesel, the particle number concentrations show single peak distribution curves (nucleation mode), for the pure biodiesel, particle number concentrations show bimodal distribution including nucleation mode and accumulation mode on full load speed characteristics and 1400 r/min and 2200 r/min load characteristics; on full load speed characteristics, for BD100, the peak of particle number concentration of BD100 is lowest, compared with D100, it is about one order of magnitude lower; on 1400r/min load characteristics, with the biodiesel proportion increasing, the number of nucleation mode and accumulation mode particles decreases; on lower than 1800 r/min full load speed characteristics and 1400 r/min and 2200 r/min load characteristics, with the biodiesel proportion increasing, the particle number concentration decreases.

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