Modeling heavy-duty diesel engines using tabulated kinetics in a wide range of operating conditions

Fast and high-fidelity combustion models including detailed kinetics and turbulence chemistry interaction are necessary to support design and development of heavy-duty diesel engines. In this work, the authors intend to present and validate tabulated flamelet progress variable model based on tabulation of laminar diffusion flamelets for different scalar dissipation rate, whose predictability highly depends on the description of fuel–air mixing process in which engine mesh layout plays an important role. To this end, two grids were compared and assessed: in both grids, cells were aligned on the spray direction with such region being enlarged in the second one, where the near-nozzle and near-wall mesh resolution were also improved, which is expected to better account for both spray dynamics and flame–wall interaction dominating the combustion process in diesel engines. Flame structure, in-cylinder pressure, apparent heat release rate, and emissions for different relevant operating points were compared and analyzed to identify the most suitable mesh. Afterwards, simulations were carried out in a heavy-duty engine considering 20 operating points, allowing to comprehensively verify the validity of tabulated flamelet progress variable model. The results demonstrated that the proposed approach was capable to accurately predict in-cylinder pressure evolution and NO x formation across a wide engine map.

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Computational study of the effect of different injection angle on heavy duty diesel engine combustion

Thermal Science ◽

10.2298/tsci0903009r ◽

2009 ◽

Vol 13 (3) ◽

pp. 9-21 ◽

Cited By ~ 2

Author(s):

Ali Ranjbar ◽

Kurosh Sedighi ◽

Mousa Farhadi ◽

Mohsen Pourfallah

Keyword(s):

Diesel Engine ◽

Diesel Engines ◽

Computational Study ◽

Exhaust Emission ◽

Cylinder Pressure ◽

Heavy Duty ◽

Injection Angle ◽

Heavy Duty Diesel Engine ◽

Heavy Duty Diesel ◽

Injection Strategies

Diesel engines exhausting gaseous emission and particulate matter have long been regarded as one of the major air pollution sources, particularly in metropolitan areas, and have been a source of serious public concern for a long time. The choosing various injection strategies is not only motivated by cost reduction but is also one of the potentially effective techniques to reduce exhaust emission from diesel engines. The purpose of this study is to investigate the effect of different injection angles on a heavy duty diesel engine and emission characteristics. The varieties of injection angle were simulated and the emissions like soot and NO is calculated. The comparison between the different injection strategies was also investigated. A combustion chamber for three injection strategies (injection direction with angles of ?=67.5, 70, and 72.5 degree) was simulated. The comparative study involving rate of heat release, in-cylinder temperature, in-cylinder pressure, NO and soot emissions were also reported for different injection strategies. The case of ?=70 is optimum because in this manner the emissions are lower in almost most of crank angle than two other cases and the in-cylinder pressure, which is a representation of engine power, is higher than in the case of ?=67.5 and just a little lower than in the case of ?=72.5.

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

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4027276 ◽

2014 ◽

Vol 136 (10) ◽

Cited By ~ 13

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.

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

Volume 1: Large Bore Engines; Advanced Combustion; Emissions Control Systems; Instrumentation, Controls, and Hybrids ◽

10.1115/icef2013-19037 ◽

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.

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Robust cylinder pressure estimation in heavy-duty diesel engines

International Journal of Engine Research ◽

10.1177/1468087417713336 ◽

2017 ◽

Vol 19 (2) ◽

pp. 179-188 ◽

Cited By ~ 6

Author(s):

Serkan Kulah ◽

Alexandru Forrai ◽

Frank Rentmeester ◽

Tijs Donkers ◽

Frank Willems

Keyword(s):

Steady State ◽

Pressure Sensor ◽

Operating Conditions ◽

Added Value ◽

Cylinder Pressure ◽

Heavy Duty ◽

Adaptation Algorithm ◽

Single Cylinder ◽

Crank Angle ◽

Heavy Duty Diesel

The robustness of a new single-cylinder pressure sensor concept is experimentally demonstrated on a six-cylinder heavy-duty diesel engine. Using a single-cylinder pressure sensor and a crank angle sensor, this single-cylinder pressure sensor concept estimates the in-cylinder pressure traces in the remaining cylinders by applying a real-time, flexible crankshaft model combined with an adaptation algorithm. The single-cylinder pressure sensor concept is implemented on CPU/field-programmable gate array–based hardware. For steady-state engine operating conditions, the added value of the adaptation algorithm is demonstrated for cases in which a fuel quantity change or start of injection change is applied in a single, non-instrumented cylinder. It is shown that for steady-state and transient engine conditions, the cylinder pressure traces and corresponding combustion parameters, indicated mean effective pressure, peak cylinder pressure, and crank angle at 50% heat release, can be estimated with 1.2 bar, 6.0 bar, and 1.1 CAD inaccuracy, respectively.

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