Regulated emissions and speciated hydrocarbons from smokeless low-temperature combustion diesel engines with ultra-high exhaust gas recirculation and exhaust oxidation catalyst

2009 ◽  
Vol 223 (5) ◽  
pp. 673-683 ◽  
Author(s):  
T Li ◽  
H Ogawa
Keyword(s):  
Low Temperature ◽  
Exhaust Gas Recirculation ◽  
Combustion Regime ◽  
Oxidation Catalyst ◽  
Exhaust Gas ◽  
Low Temperature Combustion ◽  
Toxic Emissions ◽  
Temperature Combustion ◽  
Clean Diesel Combustion ◽  
Gas Recirculation

With ultra-high exhaust gas recirculation (EGR) suppressing the in-cylinder soot and nitrogen oxides (NO x) formation as well as with the exhaust oxidation catalyst removing the engine-out total unburned hydrocarbon (THC) and carbon monoxide (CO) emissions, clean diesel combustion in terms of low regulated emissions (NO x, particulate matter, THC, and CO) can be established in an operating range up to 50 per cent load. However, unregulated emissions such as aldehydes, aromatics, and 1,3-butadiene, which are seen as a severe threat to human health, are concerned when operating the engine with ultra-high EGR. In this study, the THC emissions from a diesel engine operated with ultra-high EGR low-temperature combustion were speciated using Fourier transform infrared spectroscopy. Some unregulated toxic emissions including aldehydes, aromatics, 1,3-butadiene, and some low molecular hydrocarbons dramatically increase in the ultra-high EGR low-temperature combustion regime. The exhaust oxidation catalyst is effective to remove aldehydes and some unsaturated hydrocarbons, but aromatics and methane generated from the ultra-high EGR operation are hardly reduced, particularly at higher loads.

scholarly journals Low Temperature Combustion with Multiple Injection Strategies in Single Cylinder Diesel Engine

2020 ◽  
Vol 9 (7) ◽  
pp. 779-785
Keyword(s):  
Low Temperature ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Low Temperature Combustion ◽  
Multiple Injection ◽  
Engine Emissions ◽  
Multiple Injections ◽  
Temperature Combustion ◽  
Gas Recirculation ◽  
Injection Strategies

Low-temperature combustion(LTC) with multiple injection strategies is a recent trend for NOx and soot reduction in single-cylinder diesel engines. This paper presents a technical study of past research carried out on multiple injections, which are pilot I and pilot II injection before main injection, to decrease engine soot to meet emission legislation while upholding efficiency and decrease or eliminate exhaust after treatment. Previous research indicates that extending ignition lag to enhance the proper premixing, and controlling temperature of combustion to optimal level using Exhaust Gas Recirculation, have been accepted as an important aspect to attain low temperature combustion. In this paper, we first discuss the effect pilot I injection and pilot II injection strategy through varied injection quantity and time range. Thereafter, we briefly review how pilot II injection provides better results compared with the pilot I injection, which is by reason of better premixing, improves the turbulent effect and lowers the emission. Next, we provide a broad overview of the collected works on the effect of injection pressure, temperature and rate of exhaust gas recirculation on engine emissions. We conclude by identifying a few dependencies of engine parameters in low-temperature combustion by multiple injections so as to reduce the engine emissions.

Defeat of the Soot/NOx Trade-off Using Biodiesel-Ethanol in a Moderate Exhaust Gas Recirculation Premixed Low-Temperature Combustion Mode

2013 ◽  
Vol 135 (9) ◽  
Author(s):  
Haoyue Zhu ◽  
Stanislav V. Bohac ◽  
Zhen Huang ◽  
Dennis N. Assanis
Keyword(s):  
Low Temperature ◽  
Ignition Delay ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Low Temperature Combustion ◽  
Combustion Mode ◽  
Trade Off ◽  
Temperature Combustion ◽  
Premixed Low Temperature Combustion ◽  
Gas Recirculation

The soot/nitric oxides (NOx) trade-off of diesel, biodiesel, and biodiesel–ethanol in a moderate exhaust gas recirculation (EGR) premixed low temperature combustion (LTC) mode is investigated in this study. Compared to diesel, biodiesel demonstrates poorer spray behavior and shorter ignition delay, but its oxygen content results in less soot. Blending ethanol into biodiesel enhances spray behavior, prolongs ignition delay, and further increases fuel oxygen fraction, resulting in a larger reduction in soot. In the moderate EGR premixed low temperature combustion mode, an obvious soot/NOx trade-off is demonstrated with diesel fuel. The soot/NOx trade-off is improved by biodiesel fuel and defeated by the biodiesel–ethanol blend. Low soot, low NOx, and high combustion efficiency are achieved with the biodiesel–ethanol blend and proper EGR rate.

Effects of exhaust gas recirculation on low temperature combustion using wide distillation range diesel

Energy ◽  
2013 ◽  
Vol 51 ◽  
pp. 291-296 ◽  
Author(s):  
Hongqing Feng ◽  
Zunqing Zheng ◽  
Mingfa Yao ◽  
Gang Cheng ◽  
Meiying Wang ◽  
...  
Keyword(s):  
Low Temperature ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Low Temperature Combustion ◽  
Distillation Range ◽  
Temperature Combustion ◽  
Gas Recirculation

Hydrocarbon impact on NO to NO2 conversion in a compression ignition engine under low-temperature combustion

2017 ◽  
Vol 20 (2) ◽  
pp. 216-225 ◽  
Author(s):  
Xiao Yu ◽  
Shui Yu ◽  
Ming Zheng
Keyword(s):  
Low Temperature ◽  
Concentration Ratio ◽  
Exhaust Gas Recirculation ◽  
Conversion Process ◽  
Exhaust Gas ◽  
Low Temperature Combustion ◽  
Compression Ignition ◽  
Engine Combustion ◽  
Temperature Combustion ◽  
Gas Recirculation

Compression ignition engines can employ high rates of exhaust gas recirculation to realize low-temperature combustion in order to reduce the NOx emissions. However, a substantial increase in NO2 contribution to the NOx emissions is also observed. The relationship between this NO to NO2 conversion is also affected by the hydrocarbons originating mainly from the fuel. This can have important consequences for the design of the exhaust after-treatment system. Therefore, this article presents an empirical investigation of the impact of hydrocarbon emissions on the in-cylinder NO–NO2 conversion process. First, engine motoring tests are performed with propane and NO gases dosed into the engine intake manifold. Engines with different compression ratios are employed to study the effect of in-cylinder temperature and intake HC–NO ratio on the NO–NO2 conversion process. Next, the hydrocarbon impact on the NOx survivability at different engine combustion modes is investigated using a common-rail diesel engine test platform with independent control of exhaust gas recirculation, intake boost, and exhaust back pressure. Results show that the existence of hydrocarbon has a strong promotion effect of converting NO to NO2. During compression test, NO–NO2 conversion rate can reach 95% under certain intake HC–NO concentration ratio, and the minimum HC–NO concentration ratio to sustain a high NO–NO2 conversion rate is sensitive to peak in-cylinder temperature; engine combustion results also show that hydrocarbon not only can promote the in-cylinder NO–NO2 conversion process, but also has the potential of decreasing the total NOx emissions under low-temperature combustion mode.

scholarly journals The impact of intake pressure on high exhaust gas recirculation low-temperature compression ignition engine combustion using borescopic imaging

2020 ◽  
pp. 146808742092602
Author(s):  
AK Sarangi ◽  
CP Garner ◽  
GP McTaggart-Cowan ◽  
MH Davy ◽  
GK Hargrave
Keyword(s):  
Low Temperature ◽  
Exhaust Gas Recirculation ◽  
Boost Pressure ◽  
Exhaust Gas ◽  
Low Temperature Combustion ◽  
Compression Ignition Engine ◽  
Mass Fractions ◽  
Temperature Combustion ◽  
Gas Recirculation ◽  
The Impact

In diesel engines, high levels of exhaust gas recirculation can be used to achieve low-temperature combustion, resulting in low emission levels of both nitrogen oxides (NO x) and particulate matter. This work studied the effects of varying the intake manifold pressure on in-cylinder combustion processes and engine-out emissions from a light-duty single cylinder diesel engine under conventional and high exhaust gas recirculation low-temperature combustion regimes. The work was conducted at a part-load cruise condition of 1500 r/min and at an indicated mean effective pressure of approximately 600 kPa. Exhaust gas recirculation rates were varied between 0% and 65% at absolute intake pressures of 100–150 kPa. Very low NO x emissions were achieved (<10 ppm, ∼0.05 g/kW h) for intake oxygen mass fractions below about 11%, independent of boost pressure. Smoke emission levels were lower than for non–exhaust gas recirculation combustion at oxygen mass fractions below ∼9%, depending on the boost pressure. High intake pressures reduced fuel consumption by 15% and combustion by-product emissions by 50%–60% compared to low boost. For the low intake boost case, little visible flame was apparent through borescope imaging. At higher boost pressures, intense flame luminosity was observed within the piston bowl early in the expansion stroke. Spatially averaged soot luminosity based on photomultiplier tube data showed that peak soot luminosity was five times greater and occurred 8 °CA earlier for high boost. This work demonstrates how the combination of appropriate boost pressures and exhaust gas recirculation rates can be used to mitigate the emissions and thermal efficiency penalties of high-dilution low-temperature combustion to achieve near-zero NO x operation.

Potential of in-cylinder exhaust gas recirculation stratification for combustion and emissions in diesel engines

2011 ◽  
Vol 226 (4) ◽  
pp. 547-559 ◽  
Author(s):  
W Park ◽  
S Lee ◽  
S Choi ◽  
K Min
Keyword(s):  
Low Temperature ◽  
Diesel Engines ◽  
Exhaust Gas Recirculation ◽  
Hydrocarbon Emissions ◽  
Exhaust Gas ◽  
Low Temperature Combustion ◽  
Engine Simulation ◽  
Temperature Combustion ◽  
Soot Emissions ◽  
Gas Recirculation

It is difficult to decrease the emissions of nitrogen oxides (NO x) and soot simultaneously in conventional diesel engines. Low-temperature combustion concepts have been studied in an effort to overcome this problem. Low-temperature combustion has the potential to reduce NO x and soot emissions, but it has many limitations, including narrow operating ranges, high carbon monoxide and hydrocarbon emissions, and difficulties with ignition control. Exhaust gas recirculation (EGR) stratification is another combustion concept used to reduce NO x and soot emissions simultaneously using the local non-uniformity of EGR gas instead of increasing the overall EGR rate. In this study, the EGR stratification concept was improved using computational fluid dynamics. First, a two-step piston was developed to maximize the stratified EGR effects by obtaining a favourable EGR distribution pattern and injecting fuel into the high-EGR region. Then, the possibility of combustion and emission control using stratified EGR was estimated. The ideally distributed EGR in the cylinder results showed that the region of locally high EGR effectively influences the combustion characteristics and, thus, horizontally and centrally stratified EGR has the potential to reduce the nitric oxide (NO x) and soot emissions at the same time. Engine simulation results also showed simultaneous reductions in the NO x and the soot emissions.

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