Investigation of the Optimal Injection Conditions for a PCCI Diesel Engine

2012 ◽  
Author(s):  
Yungjin Kim ◽  
Sangki Park ◽  
Kihyung Lee
Keyword(s):  
Combustion Process ◽  
Injection Rate ◽  
Homogeneous Mixture ◽  
Injection Timing ◽  
Emission Characteristics ◽  
Split Injection ◽  
Multiple Injections ◽  
Indicated Mean Effective Pressure ◽  
Main Injection ◽  
Optimal Injection

Premixed charge compression ignition (PCCI) engines have the potential with their attractive advanced combustion process to achieve a more homogeneous mixture and a lower peak combustion temperature resulting in both lower nitrogen oxides (NOx) and diesel particulate matter (PM) emissions. In this study, the spray characteristics for a PCCI engine according to various injection conditions were introduced and then the effects of injection strategies such as injection angles, injection timings and times on combustion and emissions were studied for a single cylinder PCCI engine using early multiple injections first. Add more, a method of early-main type split injection was used for a 4-cylinder PCCI engine and the effects of injection conditions on the combustion and emission characteristics were investigated. Finally flame visualization tests were performed to validate the result obtained from the engine test. The experimental results showed that the mixture formation, indicated mean effective pressure (IMEP), and emission characteristics were dominantly affected by the injection conditions and the multiple injection method resulted in higher IMEP and still low smoke level characteristics. It appeared that more homogeneous mixture could be formed with decreasing of spray penetration and increasing of fuel evaporation rate for the early multiple injections. In case of the split injection, both injection timing and injected fuel ratio of the early and main injection largely affected engine combustion and emission characteristics. From the results, as the early injection rate increased premixed combustion was activated, on the other hand, as the main injection rate increased conventional diesel combustion was activated, therefore suitable split injection conditions could be selected for the 4-cylinder PCCI engine.

Effects of Pre-Injection on Combustion Characteristics of a Single-Cylinder Diesel Engine

2009 ◽  
Author(s):  
M. Mittal ◽  
G. Zhu ◽  
T. Stuecken ◽  
H. J. Schock
Keyword(s):  
Diesel Engine ◽  
Combustion Process ◽  
Load Condition ◽  
Combustion Characteristics ◽  
Combustion Noise ◽  
Injection Timing ◽  
Single Cylinder ◽  
Multiple Injections ◽  
Main Injection ◽  
Load Conditions

Multiple injections used for diesel engines, especially pre- and post-injections, have the potential to reduce combustion noise and emissions with improved engine performance. This paper outlines the combustion characteristics of a single-cylinder diesel engine with multiple injections. The effects of pre-injection (multi-injection) on combustion characteristics are presented in a single-cylinder diesel engine at different engine speeds and load conditions. A common rail fuel system with a solenoid injector, driven by a peak and hold circuit, is used in this work. This enables us to control the number of injections, fuel injection timing and duration, and the fuel rail pressure that can be used to optimize the engine combustion process (e.g., eliminate engine knock). Mass fraction burned and burn durations are determined by analyzing the measured in-cylinder pressure data. Results are compared with the cases when no pre-injection was used, i.e. only main injection, at the same engine speeds and load conditions. In each study, different cases are considered with the variation in main injection timing. It is found that at full-load condition and lower engine speeds pre-injection is an effective method to alter the engine burn rate and hence to eliminate knock.

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.

scholarly journals An Investigation of the Influence of Gas Injection Rate Shape on High-Pressure Direct-Injection Natural Gas Marine Engines

Energies ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2571 ◽  
Author(s):  
Jingrui Li ◽  
Jietuo Wang ◽  
Teng Liu ◽  
Jingjin Dong ◽  
Bo Liu ◽  
...  
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Fuel Consumption ◽  
Direct Injection ◽  
Gas Injection ◽  
Injection Rate ◽  
Emission Characteristics ◽  
Nox Emissions ◽  
Indicated Mean Effective Pressure ◽  
Marine Engines

High-pressure direct-injection (HPDI) natural gas marine engines are widely used because of their higher thermal efficiency and lower emissions. The effects of different injection rate shapes on the combustion and emission characteristics were studied to explore the appropriate gas injection rate shapes for a low-speed HPDI natural gas marine engine. A single-cylinder model was established and the CFD model was validated against experimental data from the literature; then, the combustion and emission characteristics of five different injection rate shapes were analyzed. The results showed that the peak values of in-cylinder pressure and heat release rate profiles of the triangle shape were highest due to the highest maximum injection rate, which occurred in a phase close to the top dead center. The shorter combustion duration of the triangle shape led to higher indicated mean effective pressure (IMEP) and NOx emissions compared with other shapes. The higher initial injection rates of the rectangle and slope shapes had a negative effect on the ignition delay periods of pilot fuel, which resulted in lower in-cylinder temperature and NOx emissions. However, due to the lower in-cylinder temperature, the engine power output was also lower. Otherwise, soot, unburned hydrocarbon (UHC), and CO emissions and indicated specific fuel consumption (ISFC) increased for both rectangle and slope shapes. The trapezoid and wedge shapes achieved a good balance between fuel consumption and emissions.

1-D Simulation of a Diesel Engines Injection Timing

2014 ◽  
Vol 494-495 ◽  
pp. 201-205
Author(s):  
Qian Xi Yin ◽  
Yu Liu ◽  
Guo Dong Feng ◽  
Qing Dang Wang ◽  
Feng Bian ◽  
...  
Keyword(s):  
Diesel Engines ◽  
Injection Timing ◽  
Emission Characteristics ◽  
Power Characteristics ◽  
Main Work ◽  
Output Torque ◽  
Main Injection ◽  
Simulation Results ◽  
Experimental Data Analysis ◽  
Engine Power

Using GT-POWER to simulate a diesel engines injection timing, calibrating simulation model has been done according to experimental data. Analysis of the effect on engine power characteristics and emission characteristics caused by different pre-injection timing and main injection timing is the main work. The simulation results show that, the output torque and NOx increased when the injection timing is advanced. In contrast, the soot emission is decreased when the injection timing is advanced.

Effect of Injection System Parameters on Performance and Emission Characteristics of a Small Single Cylinder Diesel Engine

2021 ◽  
Vol 18 (2) ◽  
Author(s):  
D.K. Dond ◽  
N.P. Gulhane
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Direct Injection ◽  
Common Rail ◽  
Injection System ◽  
Injection Timing ◽  
Emission Characteristics ◽  
Performance And Emission ◽  
System Parameters ◽  
Main Injection

Limited fossil fuel reservoir capacity and pollution caused by them is the big problem in front of researchers. In the present paper, an attempt was made to find a solution to the same. The conventional fuel injection system was retrofitted with a simple version of the common rail direct injection system for the small diesel engine. Further, the effect of injection system parameters was observed on the performance and emission characteristics of the retrofitted common rail direct injection diesel engine. The parameters such as injection pressure, the start of pilot injection timing, the start of main injection timing and quantity of percentage fuel injection during the pilot and main injection period were considered for experimental investigation. It was observed that all the evaluated parameters were found vital for improving the engine’s performance and emission characteristics. The retrofitted common rail direct injection system shows an average 7% rise in brake thermal efficiency with economic, specific fuel consumption. At the same time, much more reduction in hydrocarbon, carbon monoxide and smoke opacity with a penalty of a slight increase in nitrogen oxides.

scholarly journals Assessment on the consequences of injection strategies on combustion process and particle size distributions in Euro VI medium-duty diesel engine

2019 ◽  
Vol 21 (4) ◽  
pp. 683-697 ◽  
Author(s):  
Vicente Bermúdez ◽  
Antonio García ◽  
David Villalta ◽  
Lian Soto
Keyword(s):  
Particle Size ◽  
Diesel Engine ◽  
Size Distribution ◽  
Particle Concentration ◽  
Combustion Process ◽  
Injection Pressure ◽  
Injection Timing ◽  
Injection Parameters ◽  
Main Injection ◽  
Injection Strategies

Although there are already several works where the influence of injection parameters on exhaust emissions, and specifically on particulate matter emissions, in diesel engines has been evaluated, the diversity in the results that can be found in the literature indicates the need to carry out new experiments that can provide more information about the influence of these parameters on modern diesel engines. This study intends to be placed within this scientific framework, hence a parametric study was carried out based on the independent modification of the main injection timing and the injection pressure with respect to the nominal conditions of a new Euro VI direct injection diesel engine. Four steady-state operation points of the engine map were chosen: 25% load and 950 r/min, 50% load and 1500 r/min, 75% load and 2000 r/min and 100% load and 2200 r/min, where in each of these operation points, the variations of the injection parameters in the study on the combustion process and its consequent impact on the particle size distribution, including an analysis of the geometric mean diameter values, were evaluated. The results showed that the different injection strategies adopted, despite not significantly affecting the engine efficiency, did cause a significant impact on particle number emissions. At the low load operation, the size distribution showed a bimodal structure, and as the main injection timing was delayed and the injection pressure was decreased, the nucleation-mode particle concentration decreased, while the accumulation-mode particle concentration increased. In addition, at medium load, the nucleation-mode particle emission decreased considerably while the accumulation-mode particle emission increased, and this increase was much greater with the main injection timing delay and the injection pressure reduction. Similar behavior was observed at high load, but with a much more prominent pattern.

scholarly journals Effect of biodiesel on the development of split injection characteristics

2019 ◽  
Vol 177 (2) ◽  
pp. 103-107
Author(s):  
Stasys SLAVINSKAS ◽  
Gvidonas LABECKAS ◽  
Tomas MICKEVIČIUS
Keyword(s):  
Diesel Fuel ◽  
Fuel Injection ◽  
Pressure Fluctuations ◽  
Injection Rate ◽  
Inlet Pressure ◽  
Injection System ◽  
Split Injection ◽  
Common Rail Injection System ◽  
Main Injection ◽  
Injection Phase

The paper presents the experimental test results of a common rail injection system operating with biodiesel and the diesel fuel. The three fuel split injection strategies were implemented to investigate the effects made by biodiesel and a fossil diesel fuel on the history of injector inlet pressure and the injection rate. In addition, the three intervals between split injections and the different injection pressures were used to obtain more information about the studied subjects. The obtained results showed that the peak mass injection rates of the main injection phase were slightly higher when using biodiesel than the respective values measured with the normal diesel fuel. Because the first injection phase activated the fuel pressure fluctuations along the high-pressure line and in front of the injector, the time-span between injections has an impact on the injector inlet pressure and thus the fuel injection rate during the second injection phase. Since the nozzle closes little later for biodiesel, the injector inlet pressure also occurred latter in the cycle.

scholarly journals Effects of Various Fuels on Combustion and Emission Characteristics of a Four-Stroke Dual-Fuel Marine Engine

2021 ◽  
Vol 9 (10) ◽  
pp. 1072
Author(s):  
Van Chien Pham ◽  
Beom-Seok Rho ◽  
Jun-Soo Kim ◽  
Won-Ju Lee ◽  
Jae-Hyuk Choi
Keyword(s):  
Alternative Fuels ◽  
Numerical Study ◽  
Combustion Process ◽  
Simulation Software ◽  
Dual Fuel ◽  
Injection Timing ◽  
Emission Characteristics ◽  
Marine Engine ◽  
Adjustment Method ◽  
Simulation Results

A numerical study was carried out to investigate the effects of methane (CH4), ethane (C2H6), propane (C3H8), butane (C4H10), and dimethyl ether (DME) on the combustion and emission characteristics of a four-stroke gas-diesel dual-fuel (DF) marine engine at full load. Three-dimensional simulations of the combustion process and emission formation inside the engine cylinder in the diesel and DF modes were performed using the AVL FIRE R2018a simulation software to analyze the in-cylinder pressure, temperature, and emission characteristics. The simulation results agreed well with the measured values reported in the engine shop test technical data. The simulation results showed reductions in the in-cylinder peak pressure and temperatures, as well as the emission formations, in the DF modes in comparison to the diesel mode. The DF mode could significantly reduce nitric oxide (NO) emissions (up to 96.225%) of DME compared to the diesel mode. Meanwhile, C3H8 and CH4 fuels effectively reduced the soot (up to 82.78%) and carbon dioxide (CO2) emissions (by 21.33%), respectively, compared to the diesel mode. However, the results also showed longer ignition delay times of the combustion processes when the engine operated in the DF mode, particularly in the DME-diesel mode. The combustion and emission characteristics of the engine were also analyzed when varying the injection timing; the results showed that applying the injection timing adjustment method could further address NO emission problems but led to a decrease in the engine power. Therefore, it is necessary to consider the benefits and disadvantages of adopting the injection timing adjustment strategy to address certain engine emission problems. This study successfully analyzed the benefits of using various gas fuels as alternative fuels and the injection timing adjustment method in DF marine engines to meet the International Maritime Organization (IMO) emission regulations without the use of any emission after-treatment devices.

scholarly journals Optimizing split fuel injection strategies to avoid pre-ignition and super-knock in turbocharged engines

2019 ◽  
Vol 22 (1) ◽  
pp. 199-221 ◽  
Author(s):  
Eshan Singh ◽  
Kai Morganti ◽  
Robert Dibble
Keyword(s):  
Fuel Injection ◽  
Combustion Process ◽  
Effective Pressure ◽  
Split Injection ◽  
Injection Strategy ◽  
Gasoline Engines ◽  
Specific Output ◽  
Indicated Mean Effective Pressure ◽  
Cycle Variation ◽  
Injection Strategies

Fuel injection strategies often have a considerable impact on pre-ignition in high specific output gasoline engines. Splitting the injection event into two or more pulses has been widely explored as one means of reducing pre-ignition. As effective as these strategies can be with respect to pre-ignition suppression, they often introduce other compromises into the combustion process, for example, reduced indicated mean effective pressure or greater cycle-to-cycle variation. This study examines a split injection strategy with up to three injection pulses for suppressing pre-ignition, while optimizing the start of injection and duration of injection to minimize the associated compromises on the combustion process. The results demonstrate that splitting the injection event generally lowers the in-cylinder temperature and reduces the fuel mass that reaches the cylinder liner. This leads to a lower probability of creating oil-fuel droplets, which may act as a precursor for pre-ignition. The split injection strategy with a late injection when the piston is close to top dead center is shown to perform even better in terms of pre-ignition suppression, while providing comparable indicated mean effective pressure and cycle-to-cycle variation to the baseline case with a single injection pulse. Finally, the injection pressure is varied to establish an optimal combination of operating parameters for avoiding pre-ignition in high specific output gasoline engines.

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