Variation of Sauter Mean Diameter of Droplets of Gasoline Engine Intake Port during Cold Start

2012 ◽  
Vol 433-440 ◽  
pp. 6390-6396
Author(s):  
Pei Yong Ni ◽  
Xiang Li Wang
Keyword(s):  
Engine Speed ◽  
Gasoline Engine ◽  
Cold Start ◽  
Droplet Velocity ◽  
Injection Timing ◽  
Fuel Temperature ◽  
Sauter Mean Diameter ◽  
Initial Droplet ◽  
Mean Diameter ◽  
Fuel Evaporation

The reduction of sauter mean diameter (SMD) of droplets means the percent of the evaporated fuel, which is important to the formation of the combustible mixture in a port-injection gasoline engine during cold-start. Three-dimensional numerical simulation of SMD of the droplets in the inlet port of a gasoline engine was employed using the CFD software. This paper presented the effect of multi-parameters on SMD of the droplets including initial droplet velocity, intake temperature, fuel temperature, injection timing and engine speed. The simulation results show that the most influential parameters on SMD of the droplets are intake temperature and fuel temperature. The fuel evaporation rates increase approximately linearly with the intake air temperature and fuel temperature increasing. The initial droplet velocity and injection timing have a little effect on the fuel evaporation. As engine speed increases, SMD of the droplets firstly decreases and then increases. After intake-valve-open (IVO), back flow of gas in cylinders results in steep reduction of droplet diameter.

High Weber Number SMD Correlations for Pressure Atomizers

1986 ◽  
Vol 108 (1) ◽  
pp. 191-195 ◽  
Author(s):  
J. B. Kennedy
Keyword(s):  
Pressure Drop ◽  
Weber Number ◽  
Fuel Temperature ◽  
Sauter Mean Diameter ◽  
Atomization Process ◽  
Fuel Density ◽  
System Of Units ◽  
Nozzle Size ◽  
Mean Diameter ◽  
Shear Type

Published correlations for the Sauter Mean Diameter (SMD) of sprays produced by pressure atomizing injectors have generally taken the form, SMD = Aω˙B ΔPC. The system of units and the fuel properties are reflected by the coefficient A. The exponent of the flow rate term (B) has been found to be approximately 0.20. There has been less agreement relative to the appropriate value of the pressure drop exponent (C). Simmons [1] reported the value of the pressure drop exponent to be 0.354, and this value has been widely used. This paper presents recently acquired experimental data that reveal that for We greater than 10.0 a different atomization process occurs, i.e., “shear-type” breakup, which results in much finer atomization than predicted by previously reported correlations. To accurately represent the high We data, a significantly different SMD correlation form is required and is reported in this paper. The effects of large variations in the nozzle size, fuel density, viscosity, surface tension, and fuel temperature have been included in the derivation of the correlations.

Additional injection timing effects on first cycle during gasoline engine cold start based on ion current detection system

2018 ◽  
Vol 221 ◽  
pp. 55-66 ◽  
Author(s):  
Yuedong Chao ◽  
Xinye Chen ◽  
Jun Deng ◽  
Zongjie Hu ◽  
Zhijun Wu ◽  
...  
Keyword(s):  
Gasoline Engine ◽  
Detection System ◽  
Cold Start ◽  
Ion Current ◽  
Injection Timing ◽  
Timing Effects ◽  
Current Detection

scholarly journals Experimental Study of the Effect of the Expansion Segment Geometry on the Atomization of a Plain-Jet Airblast Atomizer

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yi Jin ◽  
Kanghong Yao ◽  
Xiaomin He ◽  
Kai Zhang ◽  
Yunbiao Wang
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Droplet Size Distribution ◽  
Droplet Velocity ◽  
Geometrical Parameters ◽  
Distribution Factor ◽  
Sauter Mean Diameter ◽  
Mean Velocity ◽  
Expansion Segment ◽  
Mean Diameter

In this paper, the idea of adding an expansion segment over traditional airblast atomizer is proposed to improve the spray performance. According to the systematic experiments, the Sauter mean diameter, the droplet size distribution, and the droplet axial mean velocity were obtained to evaluate the spray performance. The correlations between spray performance and four geometrical parameters of the expansion segment which include the length, the angle, the throat area, and position of liquid jet are considered. The atomizer operates at atmospheric pressure and temperature, and the air liquid ratio range is from 0.48 to 2.85. The data of the results were measured by Phase Doppler Particle Analyzer. The results show that more uniform droplet size distribution can be achieved with the addition of expansion segment, and the droplet size distribution factor q of the case adding the expansion segment is 52.8% bigger than that of the case with no expansion segment. q increases as the length and angle of expansion segment increase. The Sauter mean diameter can be reduced by either reducing the length or angle of expansion segment. As for droplet velocity, it is determined that the droplet velocity increases along the radial direction, which is noteworthy because opposite trend is reported for traditional plain-jet atomizers. With an increase of the length, angle, and throat area of the expansion segment, the droplet axial velocity decays.

The Research of Lean Combustion Characteristic of Compound Injection System of Direct Injection Engine

2014 ◽  
Vol 532 ◽  
pp. 362-366 ◽  
Author(s):  
Jiang Feng Mou ◽  
Rui Qing Chen ◽  
Yi Wei Lu
Keyword(s):  
Gasoline Engine ◽  
Direct Injection ◽  
Injection System ◽  
Intake Manifold ◽  
Combustion Characteristic ◽  
Injection Timing ◽  
Mixed Gas ◽  
Lean Burn ◽  
Direct Injection Engine ◽  
Lean Combustion

This paper studies the lean burn limit characteristic of the compound injection system of the direct-injection gasoline engine. The low pressure nozzle on the intake manifold can achieve quality homogeneous lean mixture, and the direct injection in the cylinder can realized the dense mixture gas near the spark plug. By adjusting the two injection timing and injection quantity, and a strong intake tumble flow with special shaped combustion chamber, it can produces the reverse tumble to form different hierarchical levels of mixed gas in the cylinder. Experimental results show: the compound combustion system to the original direct-injection engine lean burn limit raise 1.8-2.5 AFR unit.

Experimental and simulation study on the effect of ZSM-5 hydrocarbon catcher on the emission of gasoline engine during cold start

Fuel ◽  
2021 ◽  
pp. 122661
Author(s):  
Changling Feng ◽  
Yuanwang Deng ◽  
Yan Tan ◽  
Wei Han ◽  
Jiaqiang E ◽  
...  
Keyword(s):  
Simulation Study ◽  
Gasoline Engine ◽  
Cold Start

Influence of Low Ambient Temperatures on the Exhaust Gas and Deposit Composition of Gasoline Engines

2021 ◽  
pp. 1-11
Author(s):  
Dominik Appel ◽  
Fabian P. Hagen ◽  
Uwe Wagner ◽  
Thomas Koch ◽  
Henning Bockhorn ◽  
...  
Keyword(s):  
Internal Combustion Engines ◽  
Gasoline Engine ◽  
Cold Start ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Ex Situ ◽  
Exhaust Gas ◽  
Gasoline Engines ◽  
Ambient Temperatures ◽  
Aftertreatment Systems

Abstract To comply with future emission regulations for internal combustion engines, system-related cold-start conditions in short-distance traffic constitute a particular challenge. Under these conditions, pollutant emissions are seriously increased due to internal engine effects and unfavorable operating conditions of the exhaust aftertreatment systems. As a secondary effect, the composition of the exhaust gases has a considerable influence on the deposition of aerosols via different deposition mechanisms and on fouling processes of exhaust gas-carrying components. Also, the performance of exhaust gas aftertreatment systems may be affected disadvantageously. In this study, the exhaust gas and deposit composition of a turbocharged three-cylinder gasoline engine is examined in-situ upstream of the catalytic converter at ambient and engine starting temperatures of -22 °C to 23 °C using a Fourier-transform infrared spectrometer and a particle spectrometer. For the cold start investigation, a modern gasoline engine with series engine periphery is used. In particular, the investigation of the behavior of deposits in the exhaust system of gasoline engines during cold start under dynamic driving conditions represents an extraordinary challenge due to an average lower soot concentration in the exhaust gas compared to diesel engines and so far, has not been examined in this form. A novel sampling method allows ex-situ analysis of formed deposits during a single driving cycle. Both, particle number concentration and the deposition rate are higher in the testing procedure of Real Driving Emissions (RDE) than in the inner-city part of the Worldwide harmonized Light vehicles Test Cycle (WLTC). In addition, reduced ambient temperatures increase the amount of deposits, which consist predominantly of soot and to a minor fraction of volatile compounds. Although the primary particle size distributions of the deposited soot particles do not change when boundary conditions change, the degree of graphitization within the particles increases with increasing exhaust gas temperature.

Automated Engine Calibration Optimization Using Online Extremum Seeking

2018 ◽  
Author(s):  
Ripudaman Singh ◽  
Andrew Mansfield ◽  
Margaret Wooldridge
Keyword(s):  
Control Parameter ◽  
Gasoline Engine ◽  
Fuel Injection ◽  
Engine Performance ◽  
Extremum Seeking ◽  
Injection System ◽  
Test Time ◽  
Injection Timing ◽  
Promising Alternative ◽  
Non Linear System

Emissions compliance during engine start-up conditions is a major obstacle for current automotive manufacturers across global markets. The challenges to meeting emissions targets are both due to increasingly stringent regulations and the difficulty in developing control strategies for a high degree-of-freedom and highly non-linear system. Online extremum-seeking (ES) methods offer a promising alternative to traditional optimization based on design-of-experiment based automotive calibration. With extremum-seeking methods, results from all prior experiments are used to intelligently and efficiently generate the next iteration of the control parameter(s). In this work, the applicability of the online extremum-seeking method is explored to optimize five performance variables (injection timing for two injection events, the injection fuel mass divided between the first and second injection events, air-fuel equivalence ratio and exhaust cam timing) to minimize brake specific fuel consumption while imposing different constraints on NOx emissions. The experiments were conducted using a production turbocharged four-cylinder gasoline engine with an advanced fuel injection system. The results show the utility of the ES strategy to quickly identify optimal control parameter combinations and the emissions and engine performance improvements during the calibration process. The results also demonstrate the dramatic benefit of the ES calibration strategy in terms of test time required.

scholarly journals Atomization Quality of Twin Fluid Atomizers for Gas Turbines

1982 ◽  
Author(s):  
M. M. Elkotb ◽  
M. A. Elsayed Mahdy ◽  
M. E. Montaser
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Gas Turbines ◽  
Cone Angle ◽  
Droplet Size Distribution ◽  
Diameter Ratio ◽  
Air Pressure ◽  
Sauter Mean Diameter ◽  
Flow Number ◽  
Mean Diameter

A detailed investigation of the effect of nozzle/needle diameter ratio, normal fuel area, swirler degree, air pressure, fuel pressure on flow number, cone angle and droplet size distribution of external mixing twin fluid atomizers is given in this paper. Forty atomizers have been constructed to prevent mutual effect of various parameters. Flow number and cone angle are found to increase with nozzle/diameter ratio, and to decrease with the increase of air pressure. Optimum fuel flow is obtained at swirler angle 30-deg, while cone angle increases with increase of swirler angle. Sauter mean diameter decreases with the increase of air pressure and decrease of fuel pressure. Suitable functions are derived for droplet size distribution, Sauter mean diameter, and flow number. They are suitable to predict the geometry of the atomizer and to be used also in a prediction model for the calculation of fuel concentration and heat release.

scholarly journals Droplet Characteristics of Rotating Packed Bed in H2S Absorption: A Computational Fluid Dynamics Analysis

Processes ◽  
2019 ◽  
Vol 7 (10) ◽  
pp. 724
Author(s):  
Wang ◽  
Wu ◽  
Yang ◽  
Wang ◽  
Liu ◽  
...  
Keyword(s):  
Residence Time ◽  
Droplet Diameter ◽  
Packed Bed ◽  
Droplet Velocity ◽  
Radial Position ◽  
Selective Absorption ◽  
Rotating Speed ◽  
Initial Droplet ◽  
Rotating Packed Bed ◽  
Computational Fluid Dynamics Analysis

Rotating packed bed (RPB) has been demonstrated as a significant and emerging technology to be applied in natural gas desulfurization. However, droplet characteristics and principle in H2S selective absorption with N-methyldiethanolamine (MDEA) solution have seldom been fully investigated by experimental method. Therefore, a 3D Eulerian–Lagrangian approach has been established to investigate the droplet characteristics. The discrete phase model (DPM) is implemented to track the behavior of droplets, meanwhile the collision model and breakup model are employed to describe the coalescence and breakup of droplets. The simulation results indicate that rotating speed and radial position have a dominant impact on droplet velocity, average residence time and average diameter rather than initial droplet velocity. A short residence time of 0.039–0.085 s is credited in this study for faster mass transfer and reaction rate in RPB. The average droplet diameter decreases when the initial droplet velocity and rotating speed enhances. Restriction of minimum droplet diameter for it to be broken and an appropriate rotating speed have also been elaborated. Additional correlations on droplet velocity and diameter have been obtained mainly considering the rotating speed and radial position in RPB. This proposed formula leads to a much better understanding of droplet characteristics in RPB.

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