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.

Low-Temperature Combustion Within a HSDI Diesel Engine Using Multiple-Injection Strategies

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Tiegang Fang ◽  
Robert E. Coverdill ◽  
Chia-Fon F. Lee ◽  
Robert A. White
Keyword(s):  
Low Temperature ◽  
Heat Release ◽  
Injection Pressure ◽  
Diffusion Combustion ◽  
Injection Timing ◽  
Low Temperature Combustion ◽  
Conventional Combustion ◽  
Main Injection ◽  
Temperature Combustion ◽  
Injection Strategies

Low-temperature compression ignition combustion employing multiple-injection strategies in an optical high-speed direct injection diesel engine was investigated. Heat release characteristics were analyzed. The whole cycle combustion process was visualized by imaging the natural flame luminosity. The NOx emissions were measured in the exhaust pipe. The effects of the pilot injection timing, pilot fuel quantity, main injection timing, operating load, and injection pressure on the combustion and emissions were studied. Low-temperature combustion modes were achieved by using a small pilot injection with an injection timing much earlier than top dead center (TDC) followed by a main injection after TDC. The results were compared with conventional diesel (diffusion) combustion for comparison purposes. A 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. A highly luminous flame was observed for the conventional combustion condition while a 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. Compared with the conventional diffusion combustion, simultaneous reductions in soot and NOx were obtained for the low-temperature combustion mode under similar operating loads. For high-load conditions, higher NOx emissions were obtained due to higher in-cylinder temperatures. However, compared with the conventional combustion case, a significant reduction in soot was achieved for the high-load conditions, which shows that increasing injection pressure greatly reduces soot emissions.

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.

Effects of fuel properties on combustion and pollutant emissions of a low temperature combustion mode diesel engine

Fuel ◽  
2020 ◽  
Vol 267 ◽  
pp. 117123 ◽  
Author(s):  
Song Li ◽  
Jinping Liu ◽  
Yu Li ◽  
Mingrui Wei ◽  
Helin Xiao ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Low Temperature ◽  
Fuel Properties ◽  
Pollutant Emissions ◽  
Low Temperature Combustion ◽  
Combustion Mode ◽  
Temperature Combustion

CFD Analysis of Diesel-Methane Dual Fuel Low Temperature Combustion at Low Load and High Methane Substitution

2018 ◽  
Author(s):  
Andrea Aniello ◽  
Lorenzo Bartolucci ◽  
Stefano Cordiner ◽  
Vincenzo Mulone ◽  
Sundar R. Krishnan ◽  
...  
Keyword(s):  
Low Temperature ◽  
Heat Release ◽  
Diesel Fuel ◽  
Single Stage ◽  
Dual Fuel ◽  
Low Temperature Combustion ◽  
Two Stage ◽  
Low Load ◽  
Temperature Heat ◽  
Temperature Combustion

Over the last few decades, emissions regulations for internal combustion engines have become increasingly restrictive, pushing researchers around the world to exploit innovative propulsion solutions. Among them, the dual fuel low temperature combustion (LTC) strategy has proven capable of reducing fuel consumption and while meeting emissions regulations for oxides of nitrogen (NOx) and particulate matter (PM) without problematic aftertreatment systems. However, further investigations are still needed to reduce engine-out hydrocarbon (HC) and carbon monoxide (CO) emissions as well as to extend the operational range and to further improve the performance and efficiency of dual-fuel engines. In this scenario, the present study focuses on numerical simulation of fumigated methane-diesel dual fuel LTC in a single-cylinder research engine (SCRE) operating at low load and high methane percent energy substitution (PES). Results are validated against experimental cylinder pressure and apparent heat release rate (AHRR) data. A 3D full-cylinder RANS simulation is used to thoroughly understand the influence of the start of injection (SOI) of diesel fuel on the overall combustion behavior, clarifying the causes of AHRR transition from two-stage AHRR at late SOIs to single-stage AHRR at early SOIs, low temperature heat release (LTHR) behavior, as well as high HC production. The numerical campaign shows that it is crucial to reliably represent the interaction between the diesel spray and the in-cylinder charge to match both local and overall methane energy fraction, which in turn, ensures a proper representation of the whole combustion. To that aim, even a slight deviation (∼3%) of the trapped mass or of the thermodynamic conditions would compromise the numerical accuracy, highlighting the importance of properly capturing all the phenomena occurring during the engine cycle. The comparison between numerical and experimental AHRR curves shows the capability of the numerical framework proposed to correctly represent the dual-fuel combustion process, including low temperature heat release (LTHR) and the transition from two-stage to single stage AHRR with advancing SOI. The numerical simulations allow for quantitative evaluation of the residence time of vapor-phase diesel fuel inside the combustion chamber and at the same time tracking the evolution of local diesel mass fraction during ignition delay — showing their influence on the LTHR phenomena. Oxidation regions of diesel and ignition points of methane are also displayed for each case, clarifying the reasons for the observed differences in combustion evolution at different SOIs.

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
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