Study on the Transient Injection Rate of Each Nozzle Hole in the Combustion Process of Diesel Engine

2020 ◽  
Vol 143 (7) ◽  
Author(s):  
Liying Zhou ◽  
Yu Liang
Keyword(s):  
Diesel Engine ◽  
Exothermic Reaction ◽  
Combustion Process ◽  
Injection Rate ◽  
Dynamics Simulation ◽  
Ratio Distribution ◽  
Fuel Distribution ◽  
Injection Quantity ◽  
Nozzle Hole ◽  
Injection Rates

Abstract Based on the measured injection rates obtained from the spray momentum experiment, the three-dimensional computational fluid dynamics simulation study on the effect of injection rate from each nozzle hole on spray characteristics and combustion process was conducted for a one-cylinder diesel engine. The simulation model was successfully verified by the data of the experiment. The results show that at the beginning and mid-stages of injection, the nozzles with a higher transient injection rate exhibit higher jet velocity, bigger spray penetration distance, and wider equivalence ratio distribution. Besides, the disturbance induced by fuel injection on their surrounding gas is higher. Due to the difference in injection rates from each nozzle hole in the cylinder, gas–fuel mixtures are non-uniform. In the case of measured injection rates from each nozzle hole, Hole 4 records the highest instantaneous injection rate. This results in the injection of more fuel during ignition delay. More heat generated from thermal chain reactions raises fuel spray temperatures and quicker ignition of mixtures. In the case of uniform simulated injection rate (injection quantity values are the same as in the previous case), more uniform flow fields and stronger small swirl motions were generated that enhance fuel atomization and mixture formations. At the later stages of injection and combustion, quicker diesel fuel burning rate with a centralized exothermic reaction process occurs due to in-cylinder uniform fuel distribution and air motion. In the case of simulating uniform injection rate from three holes and non-injection from one (same injection quantity values as previous cases), uneven fuel distribution that occurs in the cylinder will result in poor mixture formations and subsequently poor combustion, and more afterburning will occur.

Numerical Simulation on Effect of Nozzle-Hole Layout on Spray Characteristics and Combustion in a DI Diesel Engine

2012 ◽  
Vol 476-478 ◽  
pp. 448-452
Author(s):  
Jun Zhang ◽  
Chang Pu Zhao ◽  
Nai Zhuan Chen ◽  
Da Lu Dong ◽  
Bo Zhong
Keyword(s):  
Numerical Simulation ◽  
Diesel Engine ◽  
Direct Injection ◽  
Combustion Process ◽  
Three Dimensional ◽  
Three Dimensional Model ◽  
Spray Characteristics ◽  
Fuel Atomization ◽  
Di Diesel Engine ◽  
Nozzle Hole

Diesel spray characteristics are closely related to the combustion of the engine where the spray tip penetration and the fuel atomization play a key role especially for direct injection (DI) diesel engine. With different nozzles, the fuel atomization and evaporation will be different thereby affecting the combustion and emission characteristics. A three-dimensional model is built based on the parameters of a DI diesel engine, and its validation is also validated. Three nozzle-hole layouts are designed in this research, including the conventional hole, multi-hole, and group-hole. The spray characteristics and combustion process are studied with three different nozzle-hole layouts by the way of numerical simulation. Further more, the effect of inter-hole spacing of group-hole nozzle on the evaporation rate and combustion process is researched here.

Effect of Sauter Mean Diameter on Combustion Related Parameters in a Large-Bore Marine Diesel Engine

1999 ◽  
Author(s):  
Stanislav N. Danov ◽  
Ashwani K. Gupta
Keyword(s):  
Diesel Engine ◽  
Droplet Size ◽  
Fuel Injection ◽  
Combustion Process ◽  
Injection Rate ◽  
Gas Mixture ◽  
Fuel Droplet ◽  
Compression Pressure ◽  
Chain Reactions ◽  
Fuel Vaporization

Abstract A mathematical model of combustion process in a diesel engine has been developed according to the theory of chain reactions for the higher hydrocarbon compounds. The instantaneous rates of fuel vaporization and combustion are defined in terms of the current values of temperature, pressure, concentration of fuel vapors, overall diffusion rate, fuel injection rate, and mean fuel droplet size in terms of the SMD. Numerical experiments have been carried out for investigating the interdependency between various combustion-related parameters. Specifically, the effect of fuel droplet size (in terms of SMD) on the subsequent combustion parameters, such as, pressure, temperature, thermodynamic properties of air/gas mixture, heat transfer, fuel vaporization, combustion rate, current A/F ratio and gas mixture composition. In addition the integral indicator parameters of the engine, such as, mean indicated pressure, peak pressure, compression pressure have been analyzed.

scholarly journals Effects of Injection Rate Profile on Combustion Process and Emissions in a Diesel Engine

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Fuqiang Bai ◽  
Zuowei Zhang ◽  
Yongchen Du ◽  
Fan Zhang ◽  
Zhijun Peng
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Combustion Process ◽  
Injection Rate ◽  
Injection System ◽  
Nox Emissions ◽  
Release Process ◽  
Common Rail Injection System ◽  
Soot Emissions ◽  
Rate Profile

When multi-injection is implemented in diesel engine via high pressure common rail injection system, changed interval between injection pulses can induce variation of injection rate profile for sequential injection pulse, though other control parameters are the same. Variations of injection rate shape which influence the air-fuel mixing and combustion process will be important for designing injection strategy. In this research, CFD numerical simulations using KIVA-3V were conducted for examining the effects of injection rate shape on diesel combustion and emissions. After the model was validated by experimental results, five different shapes (including rectangle, slope, triangle, trapezoid, and wedge) of injection rate profiles were investigated. Modeling results demonstrate that injection rate shape can have obvious influence on heat release process and heat release traces which cause different combustion process and emissions. It is observed that the baseline, rectangle (flat), shape of injection rate can have better balance between NOx and soot emissions than the other investigated shapes. As wedge shape brings about the lowest NOx emissions due to retarded heat release, it produces the highest soot emissions among the five shapes. Trapezoid shape has the lowest soot emissions, while its NOx is not the highest one. The highest NOx emissions were produced by triangle shape due to higher peak injection rate.

scholarly journals Effect Analysis on the Performance Enhancement and Emission Reduction of Diesel Engine Fueled with Biodiesel Fuel Based on an Improved Model

2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Weigang Yu ◽  
Zhiqing Zhang ◽  
Bo Liu
Keyword(s):  
Heat Transfer ◽  
Diesel Engine ◽  
Performance Enhancement ◽  
Combustion Process ◽  
Weight Coefficient ◽  
Injection Rate ◽  
Heat Transfer Model ◽  
Biodiesel Fuel ◽  
Transfer Model ◽  
Load Characteristics

To increase the efficiency and accuracy of computing, an improved combined weight coefficient is used to develop an improved heat transfer model in AVL-BOOST environment. Similarly, a five-component biodiesel skeletal mechanism is employed to investigate the combustion process of biodiesel fuel. Then, the AVL-BOOST model is validated by the experimental results under different conditions. Finally, the improved heat transfer model is employed to investigate the propulsion and load characteristics of diesel engine fueled with biodiesel fuel in terms of power, BSFC, soot, and NOx emission. The result shows that the errors between experiment and simulation are less than 2% and the simulation model can predict the propulsion and load characteristics of the diesel engine. In addition, the comprehensive characteristic of case 5 is the best. Moreover, the big inject orifice is not beneficial to the fuel atomization and more soot is produced. Thus, it is very important to choose the appropriate injection rate reasonably.

scholarly journals Parametric Study of Injection Rates With Solenoid Injectors in an Injection Quantity and Rate Measuring Device

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
Stephen Busch ◽  
Paul C. Miles
Keyword(s):  
Parametric Study ◽  
Single Injection ◽  
Injection Rate ◽  
Hydraulic Pressure ◽  
Measuring Device ◽  
Injection Quantity ◽  
Main Injection ◽  
Fast Acting ◽  
Measuring Unit ◽  
Injection Rates

A Moehwald HDA (HDA is a German acronym: Hydraulischer Druckanstieg: hydraulic pressure increase) injection quantity and rate measuring unit is used to investigate injection rates obtained with a fast-acting, preproduction diesel solenoid injector. Experimental parametric variations are performed to determine their impact on measured injection rate traces. A pilot–main injection strategy is investigated for various dwell times; these preproduction injectors can operate with very short dwell times with distinct pilot and main injection events. Dwell influences the main injection rate shape. A comparison between a diesel-like fuel and a gasoline-like fuel shows that injection rates are comparable for a single injection but dramatically different for multiple injections with short dwells.

scholarly journals Effects of Two Pilot Injection on Combustion and Emissions in a PCCI Diesel Engine

Energies ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1651
Author(s):  
Deqing Mei ◽  
Qisong Yu ◽  
Zhengjun Zhang ◽  
Shan Yue ◽  
Lizhi Tu
Keyword(s):  
Diesel Engine ◽  
Combustion Process ◽  
Exhaust Gas ◽  
Pilot Injection ◽  
Compression Ignition ◽  
Ignition Timing ◽  
Turbocharged Diesel Engine ◽  
Injection Quantity ◽  
Low Load ◽  
Gas Recirculation

The effects of two pilot injections on combustion and emissions were evaluated in a single−cylinder turbocharged diesel engine, which operated in premixed charge compression ignition (PCCI) modes with multiple injections and heavy exhaust gas recirculation under the low load by experiments and simulation. It was revealed that with the delay of the start of the first pilot injection (SOI−P1) or the advance of the start of second pilot injection (SOI−P2), respectively, the pressure, heat release rate (HRR), and temperature peak were all increased. Analysis of the combustion process indicates that, during the two pilot injection periods, the ignition timing was mainly determined by the SOI−P2 while the first released heat peak was influenced by SOI−P1. With the delay of SOI−P1 or the advance of SOI−P2, nitrogen oxide (NOx) generation increased significantly while soot generation varied a little. In addition, increasing Q1 and decreasing the second pilot injection quantity (Q2) can manipulate the NOx and soot at a low level. The advance in SOI−P2 of 5 °CA couple with increasing Q1 and reducing Q2 was proposed, which can mitigate the compromise between emissions and thermal efficiency under the low load in the present PCCI mode.

scholarly journals Investigation on the Performance Enhancement and Emission Reduction of a Biodiesel Fueled Diesel Engine Based on an Improved Entire Diesel Engine Simulation Model

Processes ◽  
2021 ◽  
Vol 9 (1) ◽  
pp. 104
Author(s):  
Weigang Yu ◽  
Zhiqing Zhang ◽  
Bo Liu
Keyword(s):  
Heat Transfer ◽  
Diesel Engine ◽  
Simulation Model ◽  
Combustion Process ◽  
Injection Rate ◽  
Heat Transfer Model ◽  
Injection System ◽  
Biodiesel Fuel ◽  
Transfer Model ◽  
Load Characteristics

In order to improve the efficiency of the diesel engine and reduce emissions, an improved heat transfer model was developed in an AVL-BOOST environment which is a powerful and user-friendly software for engine steady-state and transient performance analysis. The improved heat transfer model considers the advantages of the Woschni1978 heat transfer model and Honhenberg heat transfer model. In addition, a five-component biodiesel skeletal mechanism containing 475 reactions and 134 species was developed to simulate the fuel spray process and combustion process since it contained methyl linolenate, methyl linoleate, methyl oleate, methyl stearate, and methyl palmitate, which are a majority component in most biodiesel. Finally, the propulsion and load characteristics of a diesel engine fueled with biodiesel fuel were investigated by the improved heat transfer model in term of power, brake specific fuel consumption (BSFC), soot and NOx emissions. Similarly, the effects of the fuel injection rate on the diesel engine’s characteristic fueled with biodiesel was studied. The result showed that the errors between experiment and simulation were less than 2%. Thus, the simulation model could predict the propulsion and load characteristics of the diesel engine. The nozzle diameter, injection pressure, and injection advance angle are significant to the injection system. Thus, it is very important to choose the injection rate reasonably.

1D Engine Simulation of a Small HSDI Diesel Engine Applying a Predictive Combustion Model

2006 ◽  
Author(s):  
T. Cerri ◽  
A. Onorati ◽  
E. Mattarelli
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Direct Injection ◽  
Combustion Process ◽  
Numerical Approach ◽  
Injection Rate ◽  
Operating Conditions ◽  
Combustion Model ◽  
Full Load ◽  
Partial Load

The paper analyses, by means of a parallel experimental and computational investigation, the performances of a small HSDI turbocharged Diesel engine. As far as the numerical approach is concerned, an in-house ID research code for the simulation of the whole engine system has been enhanced by the introduction of a multi-zone quasi-dimensional combustion model, tailored for multi-jet direct injection Diesel engines. This model takes into account the most relevant issues of the combustion process: the spray development, the in-cylinder air-fuel mixing process, the ignition and formation of the main pollutant species, such as nitrogen oxides and particulate. The prediction of the spray basic patterns requires the previous knowledge of the fuel injection rate. Since the direct measure of this quantity at each operating condition is not a very practical proceeding, an empirical model has been developed in order to provide reasonably accurate injection laws from a few experimental characteristic curves. The results of the simulation at full load are compared to experiments, showing a good agreement on brake performance and emissions. Furthermore, the combustion model tuned at full load has been applied without any change to the analysis of some operating conditions at partial load. Still, the numerical simulation provided results which qualitatively agree with experiments.

Investigation on the Match between the Nozzle Tip Penetration and the Double-Layers Diffluent Combustion Chamber Geometry

2013 ◽  
Vol 860-863 ◽  
pp. 1738-1743
Author(s):  
Kun Peng Qi ◽  
Ming Hai Li ◽  
Wu Qiang Long
Keyword(s):  
Diesel Engine ◽  
Combustion Chamber ◽  
Fuel Injection ◽  
Combustion Process ◽  
Fuel Mixture ◽  
Injection System ◽  
Double Layers ◽  
Cylinder Pressure ◽  
Combustion System ◽  
Ratio Distribution

In order to investigate the match between the nozzle tip penetration and the double-layers diffluent combustion chamber geometry, a simulation model was developed which was based on the 135 diesel engine to simulate the equivalence ratio distribution of air-fuel mixture and the temperature distribution during combustion process. At the same time, an experiment was executed by a 135 diesel engine equipped with the high-pressure common rail fuel injection system. The research results show that the air-fuel mixture becomes more uniformed and the combustion process is improved when the nozzle tip penetration is reasonable selected which lead to higher in-cylinder pressure and better brake specific fuel consumption while NOXemission is increased and soot emission is decreased for the double-layers diffluent combustion system.

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