Soot Emissions of Various Oxygenated Biofuels in Conventional Diesel Combustion and Low-Temperature Combustion Conditions

2012 ◽  
Vol 26 (3) ◽  
pp. 1900-1911 ◽  
Author(s):  
Haifeng Liu ◽  
Xiaojie Bi ◽  
Ming Huo ◽  
Chia-fon F. Lee ◽  
Mingfa Yao
Keyword(s):  
Low Temperature ◽  
Diesel Combustion ◽  
Low Temperature Combustion ◽  
Temperature Combustion ◽  
Soot Emissions

An Experimental Investigation on the Effect of Post-Injection Strategies on Combustion and Emissions in the Low-Temperature Diesel Combustion Regime

2005 ◽  
Vol 129 (1) ◽  
pp. 279-286 ◽  
Author(s):  
Hanho Yun ◽  
Rolf D. Reitz
Keyword(s):  
Low Temperature ◽  
Soot Formation ◽  
Combustion Regime ◽  
Nox Emissions ◽  
Diesel Combustion ◽  
Low Temperature Combustion ◽  
Post Injection ◽  
Temperature Combustion ◽  
Soot Emissions ◽  
Injection Strategies

In order to meet future emissions regulations, new combustion concepts are being developed. Among them, the development of low-temperature diesel combustion systems has received considerable attention. Low NOx emissions are achieved through minimization of peak temperatures during the combustion process. Concurrently, soot formation is inhibited due to a combination of low combustion temperatures and extensive fuel-air premixing. In this study, the effect of late-cycle mixing enhancement by post-injection strategies on combustion and engine-out emissions in the low-temperature (low soot and NOx emissions) combustion regime was experimentally investigated. The baseline operating condition considered for low-temperature combustion was 1500rpm, 3bar IMEP with 50% EGR rate, and extension to high loads was considered by means of post injection. Post-injection strategies gave very favorable emission results in the low-temperature combustion regime at all loads tested in this study. Since post injection leads to late-cycle mixing improvement, further reductions in soot emissions were achieved without deteriorating the NOx emissions. With smaller fuel injected amounts for the second pulse, better soot emissions were found. However, the determination of the dwell between the injections was found to be very important for the emissions.

An Experimental and Numerical Investigation on the Effect of Post Injection Strategies on Combustion and Emissions in the Low-Temperature Diesel Combustion Regime

2005 ◽  
Author(s):  
Hanho Yun ◽  
Yong Sun ◽  
Rolf D. Reitz
Keyword(s):  
Low Temperature ◽  
Soot Formation ◽  
Combustion Regime ◽  
Nox Emissions ◽  
Diesel Combustion ◽  
Low Temperature Combustion ◽  
Post Injection ◽  
Temperature Combustion ◽  
Soot Emissions ◽  
Injection Strategies

In order to meet future emissions regulations, new combustion concepts are being developed. Among them, the development of low-temperature diesel combustion systems has received considerable attention. Low NOx emissions are achieved through minimization of peak temperatures occurring during the combustion process. Concurrently, soot formation is inhibited due to a combination of low combustion temperatures and extensive fuel-air pre-mixing. In this study, the effect of late-cycle mixing enhancement by post injection strategies on combustion and engine-out emissions in the low-temperature combustion regime was investigated experimentally and numerically. The baseline operating condition considered for low-temperature combustion was 1500 rev/min, 3bar IMEP with 50% EGR rate, and extension to high loads was considered by means of post injection. Post injection strategies gave very favorable emission results in the low temperature combustion regime at all loads. With small second fuel injected amounts, better soot emissions were found. However, the determination of the dwell between the injections was found to be very important for the emissions. Since post injection leads to late-cycle mixing improvement, further reductions in soot emissions were achieved without deteriorating the NOx emissions. To explain these results, numerical analysis was also done using the KIVA-CHEMKIN code. The simulations show that optimal combustion requires that the post injection fuel avoid fuel rich regions formed from the main injection.

Cost Effective BS-VI Solution - A Combined Low Temperature Combustion and Conventional Diesel Combustion Concepts

2019 ◽  
Author(s):  
Simhachalam Juttu ◽  
Sanjeev Gothekar ◽  
Neelkanth V Marathe ◽  
Nagesh Harishchandra Walke ◽  
Subhanker Dev
Keyword(s):  
Low Temperature ◽  
Cost Effective ◽  
Diesel Combustion ◽  
Low Temperature Combustion ◽  
Temperature Combustion

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.

Low Temperature Combustion Optimization and Cycle-by-Cycle Variability Through Injection Optimization and Gas-to-Liquid Fuel-Blend Ratio

2013 ◽  
Vol 135 (7) ◽  
Author(s):  
A. D. Michailidis ◽  
R. K. Stobart ◽  
G. P. McTaggart-Cowan
Keyword(s):  
Low Temperature ◽  
Fuel Efficiency ◽  
Cyclic Behavior ◽  
Diesel Combustion ◽  
Low Temperature Combustion ◽  
Cylinder Pressure ◽  
Split Injection ◽  
Blend Ratio ◽  
Temperature Combustion ◽  
The Mean

The advent of common rail technology alongside powerful control systems capable of delivering multiple accurate fuel charges during a single engine cycle has revolutionized the level of control possible in diesel combustion. This technology has opened a new path enabling low-temperature combustion (LTC) to become a viable combustion strategy. The aim of the research work presented within this paper is the understanding of how various engine parameters of LTC optimize the combustion both in terms of emissions and in terms of fuel efficiency. The work continues with an investigation of in-cylinder pressure and IMEP cycle-by-cycle variation. Attention will be given to how repeatability changes throughout the combustion cycle, identifying which parts within the cycle are least likely to follow the mean trend and why. Experiments were conducted on a single-cylinder 510cc boosted diesel engine. LTC was affected over varying rail pressure and combustion phasing. Single and split injection regimes of varying dwell-times were investigated. All injection conditions were phased across several crank-angles to demonstrate the interaction between emissions and efficiency. These tests were then repeated with blends of 30% and 50% gas-to-liquid (GTL)-diesel blends in order to determine whether there is any change in the trends of repeatability and variance with increasing GTL blend ratio. The experiments were evaluated in terms of emissions, fuel efficiency, and cyclic behavior. Specific attention was given to how the NOx–PM trade-off changes through increased injection complexity and increasing GTL blend ratio. The cyclic behavior was analyzed in terms of in-cylinder pressure standard deviation. This gives a behavior profile of the repeatability of in-cylinder pressure in comparison to the mean. Each condition was then compared to the behavior of equivalent injection conditions in conventional diesel combustion. Short-dwell split injection was shown to be beneficial for LTC, while NOx was shown to be reduced by the substitution of GTL in the fuel. In-cylinder pressure cyclic behavior was also shown to be comparable or superior to conventional combustion in every case examined. GTL improved this further, but not in proportion to its blend ratio.

Efficiency Considerations of Later-Phased Low Temperature Diesel Combustion

2010 ◽  
Author(s):  
Bryan M. Knight ◽  
Joshua A. Bittle ◽  
Timothy J. Jacobs
Keyword(s):  
Heat Transfer ◽  
Low Temperature ◽  
Conversion Efficiency ◽  
Combustion Efficiency ◽  
Diesel Combustion ◽  
Low Temperature Combustion ◽  
Combustion Mode ◽  
Fuel Conversion ◽  
Particulate Matter Emissions ◽  
Temperature Combustion

Low temperature diesel combustion offers an opportunity to simultaneously and substantially reduce exhaust nitrogen oxides and particulate matter emissions. One issue that remains an area of investigation is the improvement of engine efficiency (i.e., specific fuel consumption) for the novel mode of combustion. The objective of this article is to assess the several parameters (i.e., friction, pumping work, combustion phasing, heat transfer rate, and combustion efficiency) that affect the brake fuel conversion efficiencies of a medium-duty diesel engine as its combustion mode is transitioned from conventional to low temperature. The analysis reveals that, in this study’s development of low temperature combustion, late combustion phasing is the primary factor causing a decrease in brake fuel conversion efficiency. To enable low temperature combustion, combustion is retarded to a point where peak rate of heat release occurs at around 24° after top dead center. Such late combustion misses the opportunity to utilize the full expansion stroke of the piston. Although exhaust hydrocarbon and carbon monoxide concentrations increase as a result of the later-phased low temperature combustion mode, combustion efficiency only drops to around 90%. This decrease in combustion efficiency accounts for only about 18.7% of the corresponding decrease in brake fuel conversion efficiency (the balance decrease being caused by the later-phased combustion). Other factors that typically deteriorate brake fuel conversion efficiency (i.e., pumping work, friction, and rate of heat transfer) are all decreased with this study’s development of low temperature combustion. It is important to note that other implementations of low temperature combustion (e.g., advanced timing low temperature combustion) may not necessarily realize the same reductions in brake fuel conversion efficiency, or reductions may not necessarily be caused by the same dominant factors that are observed in this study’s later-phased low temperature combustion mode.

Low Temperature Combustion Within an HSDI Diesel Engine Using Multiple Injection Strategies

2007 ◽  
Author(s):  
Tiegang Fang ◽  
Robert E. Coverdill ◽  
Chia-Fon F. Lee ◽  
Robert A. White
Keyword(s):  
Low Temperature ◽  
Heat Release ◽  
Injection Pressure ◽  
High Load ◽  
Injection Timing ◽  
Diesel Combustion ◽  
Low Temperature Combustion ◽  
Combustion Mode ◽  
Temperature Combustion ◽  
Load Conditions

Low Temperature Compression Ignition (LTCI) combustion employing multiple injection strategies in an optical High-Speed Direct Injection (HSDI) diesel engine was investigated in this work. Heat release characteristics were analyzed through the measurement of in-cylinder pressure. The whole cycle combustion process was visualized with a high-speed digital video camera by imaging natural flame luminosity and three-dimensional-like combustion structures were obtained by taking flame images from both the bottom of the optical piston and the side window simultaneously. The NOx emissions were measured in the exhaust pipe. The effects of pilot injection timing, pilot fuel quantity, main injection timing, operating load, and injection pressure on the combustion and emissions were studied. Low temperature combustion mode was achieved by using a small pilot injection with an injection timing much earlier than TDC followed by a main injection after TDC. For comparison, experiment of a diffusion diesel combustion case was also conducted. Premixed-combustion-dominated heat release rate pattern was seen for all the low temperature combustion cases, while a typical diffusion flame combustion heat release rate was obtained for the conventional combustion case. Highly luminous flame was observed for the conventional combustion condition while much less luminous flame was seen for the low temperature combustion cases. For the higher load and lower injection pressure cases, liquid fuel being injected into low temperature premixed flame was observed for certain cases, which was different from the conventional diesel combustion with liquid fuel injected into hot premixed flame. Compared with the conventional diffusion diesel combustion, simultaneous reduction of soot and NOx was obtained for the low temperature combustion mode at both the same and increased injection pressure with similar operating load. For high load conditions, higher NOx emissions were obtained than the low load conditions with the same injection pressure due to a higher in-cylinder temperature under high load conditions with more fuel burned. However, compared with the diffusion combustion mode with a lower load at lower injection pressure, a significant reduction of soot was achieved for the high load conditions, which shows that increasing injection pressure greatly reduce soot emissions.

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