Simulation Research of Natural Gas Injection Timing on Combustion Process in a Diesel Engine Fueled with Pilot-Ignited Directly-Injected Natural Gas

2012 ◽  
Vol 192 ◽  
pp. 132-138
Author(s):  
Nan Nan Li ◽  
Shu Hua Li ◽  
Xiao Xiao Li
Keyword(s):  
High Temperature ◽  
Diesel Engine ◽  
Natural Gas ◽  
Gas Injection ◽  
Combustion Process ◽  
Injection Timing ◽  
Simulation Research ◽  
Maximum Value ◽  
Mean Pressure ◽  
The Mean

The numerical model of diesel engine fueled with pilot-ignited directly-injected natural gas is built, and the influence of natural gas injection timing on the combustion process is studied using CFD software. And obtained the following conclusions, as the delay of natural gas injection timing, the maximum of the mean pressure and mean temperature decrease gradually and the timings for the maximum value increase. With every delay of 5 °CA of the injection, the mean pressure reduces by about 16%.As the delay of injection timing, the delay of the timing of the high temperature and the range decrease for the high temperature region, and this is beneficial for the emission of NO, but not conducive to the emission of HC、CO and PM

Simulation Research on Combustion Process in a Natural Gas-Diesel Dual-Fuel Marine Engine

2014 ◽  
Vol 525 ◽  
pp. 227-231 ◽  
Author(s):  
Min Xiao ◽  
Chun Long Feng
Keyword(s):  
Natural Gas ◽  
Total Energy ◽  
Combustion Process ◽  
Power Reduction ◽  
Dual Fuel ◽  
Injection Timing ◽  
Simulation Research ◽  
Injection Duration ◽  
Medium Speed ◽  
The Right

In order to solve the problem of Diesel natural gas dual fuel engine, such as power reduction, low charging efficiency, the conception of diesel engine fueled with pilot-ignited directly-injected liquefied natural gas is put forward. On the basis of this theory, a medium speed diesel of the marine is refitted into dual fuel engine, in order to keep original power, decrease the temperature of combustion and reduce emission. The LNG injection timing, duration of LNG injection and the different ratios the pilot diesel to total energy are studied the method of AVL FIRE software. Conclusions are as follows: When the different ratios pilot diesel to total energy is 0.5%, the engine can not work; Delaying the LNG injection timing, shortening the LNG injection duration and choose the right ratios pilot diesel to total energy can reach the indicated power of original machine, and the NOx emissions level will be greatly reduced.

scholarly journals Determining the effect of change in the gas injection timing on the performance indicators of the diesel engine operating in the diesel-gas cycle

2021 ◽  
Vol 2 (1 (110)) ◽  
pp. 52-60
Author(s):  
Serhii Kovbasenko ◽  
Andrii Holyk ◽  
Vatalii Simonenko
Keyword(s):  
Carbon Monoxide ◽  
Diesel Engine ◽  
Natural Gas ◽  
Performance Indicators ◽  
Gas Injection ◽  
Engine Performance ◽  
Environmental Indicators ◽  
Injection Timing ◽  
Compressed Natural Gas ◽  
Exhaust Gases

This paper reports a study into the fuel, economic, energy, and environmental indicators of the diesel engine operating in the diesel-gas cycle. It was established that the injection timing has a significant impact on the diesel engine indicators, in particular emissions of harmful substances with exhaust gases. The gas injection timing was investigated at crankshaft speeds n=1,300 rpm and n=1,600 rpm. At these crankshaft speeds, measurements were carried out at three different values of the injection timing. It has been determined that for each crankshaft speed of the diesel engine, the rational values of the injection timing of compressed natural gas are different. This is due to the time limits for supplying compressed natural gas to cylinders. Bench motor tests were carried out to analyze the effect of change in the gas injection timing on the diesel engine performance indicators operating in the diesel-gas cycle. The diesel engine performance indicators were also determined during a diesel cycle and during a diesel-gas cycle. The analysis has established the effect of change in the injection timing on the concentrations of carbon monoxide, hydrocarbons, nitrogen oxides, and the smoke of exhaust gases under different speed and load modes of diesel engine operation. This effect manifests itself by a slight decrease in the concentration of carbon monoxide and hydrocarbons, by the increase in the concentration of nitrogen oxides (up to 30 %), and by a significant reduction in the smoke of exhaust gases (up to 90 %). The improvement of environmental indicators of the diesel engine has been confirmed when switching its operation to the diesel-gas cycle, by 10‒16 %, with similar fuel, economic, and energy indicators. Thus, there are grounds to assert the importance of choosing and establishing the rational value for the injection timing of compressed natural gas, depending on the speed and load modes of diesel engine operating in the diesel-gas cycle.

A theoretical investigation of two possible modifications to reduce pollutant emissions from a diesel engine

2002 ◽  
Vol 216 (7) ◽  
pp. 619-628 ◽  
Author(s):  
Z Gao ◽  
W Schreiber
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Gas Injection ◽  
Combustion Process ◽  
Computer Code ◽  
Pollutant Emissions ◽  
Injection Timing ◽  
Exhaust Gas ◽  
Reduction Strategies ◽  
Emission Reduction Strategies

The goal of the study is to present and to evaluate theoretically two strategies for reducing simultaneously both particulate and NOx emission from a compression-ignited, direct injection engine. The emission reduction strategies to be considered here include auxiliary exhaust gas injection (AEGI) and a combination of exhaust gas recirculation (EGR) and AEGI. The auxiliary gas injection (AGI) process consists of the injection of a gas directly into the combustion chamber of a diesel engine during the combustion stroke to enhance fluid mixing. Increased mixing during the combustion process can lower the emission of both soot and NOx. AEGI is a process whereby exhaust gas is the injected gas used in AGI. To predict the effect of AEGI on diesel engine combustion and emission, a gas injection model was developed and used with a multidimensional simulation computer code, KIVA. The program is used to evaluate the combined effect of AEGI and EGR on pollutant emissions in a Caterpillar diesel engine. The results demonstrate that the injection timing of AEGI affects soot emissions quite differently to NOx emissions. A combination of EGR and AEGI is found to be more effective than AEGI alone for the maximum simultaneous reduction of soot and NOx emissions. It is predicted that the EGR and AEGI combination can reduce both particulate and NOx emissions by almost 50 per cent over baseline.

scholarly journals A Numerical Study on the Combustion Process and Emission Characteristics of a Natural Gas-Diesel Dual-Fuel Marine Engine at Full Load

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1342
Author(s):  
Van Chien Pham ◽  
Jae-Hyuk Choi ◽  
Beom-Seok Rho ◽  
Jun-Soo Kim ◽  
Kyunam Park ◽  
...  
Keyword(s):  
Natural Gas ◽  
Combustion Process ◽  
Simulation Software ◽  
Dual Fuel ◽  
Injection Timing ◽  
Emission Characteristics ◽  
Cylinder Pressure ◽  
Marine Engine ◽  
Full Load ◽  
Simulation Results

This paper presents research on the combustion and emission characteristics of a four-stroke Natural gas–Diesel dual-fuel marine engine at full load. The AVL FIRE R2018a (AVL List GmbH, Graz, Austria) simulation software was used to conduct three-dimensional simulations of the combustion process and emission formations inside the engine cylinder in both diesel and dual-fuel mode to analyze the in-cylinder pressure, temperature, and emission characteristics. The simulation results were then compared and showed a good agreement with the measured values reported in the engine’s shop test technical data. The simulation results showed reductions in the in-cylinder pressure and temperature peaks by 1.7% and 6.75%, while NO, soot, CO, and CO2 emissions were reduced up to 96%, 96%, 86%, and 15.9%, respectively, in the dual-fuel mode in comparison with the diesel mode. The results also show better and more uniform combustion at the late stage of the combustions inside the cylinder when operating the engine in the dual-fuel mode. Analyzing the emission characteristics and the engine performance when the injection timing varies shows that, operating the engine in the dual-fuel mode with an injection timing of 12 crank angle degrees before the top dead center is the best solution to reduce emissions while keeping the optimal engine power.

A phenomenological combustion analysis of a dual-fuel natural-gas diesel engine

2016 ◽  
Vol 231 (1) ◽  
pp. 66-83 ◽  
Author(s):  
Shuonan Xu ◽  
David Anderson ◽  
Mark Hoffman ◽  
Robert Prucka ◽  
Zoran Filipi
Keyword(s):  
Diesel Engine ◽  
Natural Gas ◽  
Heat Release ◽  
Diesel Fuel ◽  
Fuel Injection ◽  
Dual Fuel ◽  
Injection Timing ◽  
Heavy Duty ◽  
Engine System ◽  
Wiebe Function

Energy security concerns and an abundant supply of natural gas in the USA provide the impetus for engine designers to consider alternative gaseous fuels in the existing engines. The dual-fuel natural-gas diesel engine concept is attractive because of the minimal design changes, the ability to preserve a high compression ratio of the baseline diesel, and the lack of range anxiety. However, the increased complexity of a dual-fuel engine poses challenges, including the knock limit at a high load, the combustion instability at a low load, and the transient response of an engine with directly injected diesel fuel and port fuel injection of compressed natural gas upstream of the intake manifold. Predictive simulations of the complete engine system are an invaluable tool for investigations of these conditions and development of dual-fuel control strategies. This paper presents the development of a phenomenological combustion model of a heavy-duty dual-fuel engine, aided by insights from experimental data. Heat release analysis is carried out first, using the cylinder pressure data acquired with both diesel-only and dual-fuel (diesel and natural gas) combustion over a wide operating range. A diesel injection timing correlation based on the injector solenoid valve pulse widths is developed, enabling the diesel fuel start of injection to be detected without extra sensors on the fuel injection cam. The experimental heat release trends are obtained with a hybrid triple-Wiebe function for both diesel-only operation and dual-fuel operation. The ignition delay period of dual-fuel operation is examined and estimated with a predictive correlation using the concept of a pseudo-diesel equivalence ratio. A four-stage combustion mechanism is discussed, and it is shown that a triple-Wiebe function has the ability to represent all stages of dual-fuel combustion. This creates a critical building block for modeling a heavy-duty dual-fuel turbocharged engine system.

CFD Modelling of the Effects of Injection Timing on the Combustion Process and Emissions in an HSDI Diesel Engine

2012 ◽  
Author(s):  
Raouf Mobasheri ◽  
Zhijun Peng
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Cfd Simulation ◽  
Direct Injection ◽  
Combustion Process ◽  
Injection Timing ◽  
Cfd Modelling ◽  
Combustion Modeling ◽  
Pressure Trace ◽  
Hsdi Diesel Engine

High-Speed Direct Injection (HSDI) diesel engines are increasingly used in automotive applications due to superior fuel economy. An advanced CFD simulation has been carried out to analyze the effect of injection timing on combustion process and emission characteristics in a four valves 2.0L Ford diesel engine. The calculation was performed from intake valve closing (IVC) to exhaust valve opening (EVO) at constant speed of 1600 rpm. Since the work was concentrated on the spray injection, mixture formation and combustion process, only a 60° sector mesh was employed for the calculations. For combustion modeling, an improved version of the Coherent Flame Model (ECFM-3Z) has been applied accompanied with advanced models for emission modeling. The results of simulation were compared against experimental data. Good agreement of calculated and measured in-cylinder pressure trace and pollutant formation trends were observed for all investigated operating points. In addition, the results showed that the current CFD model can be applied as a beneficial tool for analyzing the parameters of the diesel combustion under HSDI operating condition.

Diesel engine performance mapping using a parametrized mixing time model

2017 ◽  
Vol 19 (2) ◽  
pp. 202-213 ◽  
Author(s):  
Michal Pasternak ◽  
Fabian Mauss ◽  
Christian Klauer ◽  
Andrea Matrisciano
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Mixing Time ◽  
Combustion Process ◽  
Engine Performance ◽  
Injection Timing ◽  
Engine Control ◽  
Reactor Model ◽  
Time Model ◽  
Tabulated Chemistry

A numerical platform is presented for diesel engine performance mapping. The platform employs a zero-dimensional stochastic reactor model for the simulation of engine in-cylinder processes. n-Heptane is used as diesel surrogate for the modeling of fuel oxidation and emission formation. The overall simulation process is carried out in an automated manner using a genetic algorithm. The probability density function formulation of the stochastic reactor model enables an insight into the locality of turbulence–chemistry interactions that characterize the combustion process in diesel engines. The interactions are accounted for by the modeling of representative mixing time. The mixing time is parametrized with known engine operating parameters such as load, speed and fuel injection strategy. The detailed chemistry consideration and mixing time parametrization enable the extrapolation of engine performance parameters beyond the operating points used for model training. The results show that the model responds correctly to the changes of engine control parameters such as fuel injection timing and exhaust gas recirculation rate. It is demonstrated that the method developed can be applied to the prediction of engine load–speed maps for exhaust NOx, indicated mean effective pressure and fuel consumption. The maps can be derived from the limited experimental data available for model calibration. Significant speedup of the simulations process can be achieved using tabulated chemistry. Overall, the method presented can be considered as a bridge between the experimental works and the development of mean value engine models for engine control applications.

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