Modelling for investigation of combustion and emission characteristics in a high-speed direct-injection diesel engine with light duty under various operating conditions

2008 ◽  
Vol 222 (11) ◽  
pp. 2159-2170 ◽  
Author(s):  
H J Kim ◽  
B W Ryu ◽  
C S Lee
Keyword(s):  
High Speed ◽  
Soot Formation ◽  
Numerical Study ◽  
Direct Injection ◽  
Operating Conditions ◽  
Injection System ◽  
Combustion Model ◽  
Injection Timing ◽  
Emission Characteristics ◽  
Fuel Mass

A numerical study was conducted to investigate combustion and emission characteristics in a high-speed direct-injection engine with a common-rail injection system under various operating conditions. In order to analyse the combustion characteristics, several models were used in this study. They were the renormalization group k– ε model, the hybrid Kelvin—Helmholtz (wave) and the Rayleigh—Taylor model, the shell auto-ignition model, and the laminar and turbulent characteristic timescale combustion model. The prediction of exhaust emissions was conducted using nitrogen oxide NO x formation with an extended Zel'dovich mechanism and Hiroyasu soot formation with the Nagle—Strickland-Constable oxidation model respectively. Experimental combustion and emission characteristics were compared with calculated results under various operating conditions, such as injection timing, injection pressure, fuel mass, and engine speed. The calculated results show similar patterns to the experimental results in the cylinder pressure and the rate of heat release. In the emissions characteristics, NO x emission decreased as injection timing was retarded and the NO x and soot amounts increased with the increase in the injected fuel mass. The calculated soot trends for various injection timings showed different patterns from the experimental trends as the injection timing were retarded.

A New Predictive ID Model for Advanced High Speed Direct Injection Diesel Engines

2004 ◽  
Author(s):  
Lurun Zhong ◽  
Naeim A. Henein ◽  
Walter Bryzik
Keyword(s):  
Diesel Engines ◽  
High Speed ◽  
Direct Injection ◽  
Combustion Process ◽  
Operating Conditions ◽  
Injection System ◽  
Injection Timing ◽  
Common Rail Injection System ◽  
Common Rail Injection ◽  
Starting Conditions

Advance high speed direct injection diesel engines apply high injection pressures, exhaust gas recirculation (EGR), injection timing and swirl ratios to control the combustion process in order to meet the strict emission standards. All these parameters affect, in different ways, the ignition delay (ID) which has an impact on premixed, mixing controlled and diffusion controlled combustion fractions and the resulting engine-out emissions. In this study, the authors derive a new correlation to predict the ID under the different operating conditions in advanced diesel engines. The model results are validated by experimental data in a single-cylinder, direct injection diesel engine equipped with a common rail injection system at different speeds, loads, EGR ratios and swirl ratios. Also, the model is used to predict the performance of two other diesel engines under cold starting conditions.

scholarly journals Influence of the diesel pilot injector configuration on ethanol combustion and performance of a heavy-duty direct injection engine

2021 ◽  
pp. 146808742110012
Author(s):  
Nicola Giramondi ◽  
Anders Jäger ◽  
Daniel Norling ◽  
Anders Christiansen Erlandsson
Keyword(s):  
Direct Injection ◽  
Engine Performance ◽  
High Load ◽  
Operating Conditions ◽  
Injection System ◽  
Injection Timing ◽  
Diesel Combustion ◽  
Heavy Duty ◽  
Pure Ethanol ◽  
Ethanol Combustion

Thanks to its properties and production pathways, ethanol represents a valuable alternative to fossil fuels, with potential benefits in terms of CO2, NOx, and soot emission reduction. The resistance to autoignition of ethanol necessitates an ignition trigger in compression-ignition engines for heavy-duty applications, which in the current study is a diesel pilot injection. The simultaneous direct injection of pure ethanol as main fuel and diesel as pilot fuel through separate injectors is experimentally investigated in a heavy-duty single cylinder engine at a low and a high load point. The influence of the nozzle hole number and size of the diesel pilot injector on ethanol combustion and engine performance is evaluated based on an injection timing sweep using three diesel injector configurations. The tested configurations have the same geometric total nozzle area for one, two and four diesel sprays. The relative amount of ethanol injected is swept between 78 – 89% and 91 – 98% on an energy basis at low and high load, respectively. The results show that mixing-controlled combustion of ethanol is achieved with all tested diesel injector configurations and that the maximum combustion efficiency and variability levels are in line with conventional diesel combustion. The one-spray diesel injector is the most robust trigger for ethanol ignition, as it allows to limit combustion variability and to achieve higher combustion efficiencies compared to the other diesel injector configurations. However, the two- and four-spray diesel injectors lead to higher indicated efficiency levels. The observed difference in the ethanol ignition dynamics is evaluated and compared to conventional diesel combustion. The study broadens the knowledge on ethanol mixing-controlled combustion in heavy-duty engines at various operating conditions, providing the insight necessary for the optimization of the ethanol-diesel dual-injection system.

Low-sooting combustion in a small-bore high-speed direct-injection diesel engine using narrow-angle injectors

2008 ◽  
Vol 222 (10) ◽  
pp. 1927-1937 ◽  
Author(s):  
T-G Fang ◽  
R E Coverdill ◽  
C-F F Lee ◽  
R A White
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Direct Injection ◽  
Fuel Efficiency ◽  
Operating Conditions ◽  
Injection Timing ◽  
Exhaust Pipe ◽  
Injection Angle ◽  
Direct Injection Diesel Engine ◽  
Combustion Flame

An optically accessible high-speed direct-injection diesel engine was used to study the effects of injection angles on low-sooting combustion. A digital high-speed camera was employed to capture the entire cycle combustion and spray evolution processes under seven operating conditions including post-top-dead centre (TDC) injection and pre-TDC injection strategies. The nitrogen oxide (NO x) emissions were also measured in the exhaust pipe. In-cylinder pressure data and heat release rate calculations were conducted. All the cases show premixed combustion features. For post-TDC injection cases, a large amount of fuel deposition is seen for a narrower-injection-angle tip, i.e. the 70° tip, and ignition is observed near the injector tip in the centre of the bowl, while for a wider-injection-angle tip, namely a 110° tip, ignition occurs near the spray tip in the vicinity of the bowl wall. The combustion flame is near the bowl wall and at the central region of the bowl for the 70° tip. However, the flame is more distributed and centralized for the 110° tip. Longer spray penetration is found for the pre-TDC injection timing cases. Liquid fuel impinges on the bowl wall or on the piston top and a fuel film is formed. Ignition for all the pre-TDC injection cases occur in a distributed way in the piston bowl. Two different combustion modes are observed for the pre-TDC injection cases including a homogeneous bulky combustion flame at earlier crank angles and a heterogeneous film combustion mode with luminous sooting flame at later crank angles. In terms of soot emissions, NO x emissions, and fuel efficiency, results show that the late post-TDC injection strategy gives the best performance.

An Experimental Investigation of the Effects of Common-Rail Injection System Parameters on Emissions and Performance in a High-Speed Direct-Injection Diesel Engine

1999 ◽  
Vol 123 (1) ◽  
pp. 167-174 ◽  
Author(s):  
P. J. Tennison ◽  
R. Reitz
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Direct Injection ◽  
Injection Pressure ◽  
Injection System ◽  
Injection Timing ◽  
Pilot Injection ◽  
Common Rail Injection System ◽  
And Performance ◽  
Emissions And Performance

An investigation of the effect of injection parameters on emissions and performance in an automotive diesel engine was conducted. A high-pressure common-rail injection system was used with a dual-guided valve covered orifice nozzle tip. The engine was a four-valve single cylinder high-speed direct-injection diesel engine with a displacement of approximately 12 liter and simulated turbocharging. The engine experiments were conducted at full load and 1004 and 1757 rev/min, and the effects of injection pressure, multiple injections (single vs pilot with main), and pilot injection timing on emissions and performance were studied. Increasing the injection pressure from 600 to 800 bar reduced the smoke emissions by over 50 percent at retarded injection timings with no penalty in oxides of nitrogen NOx or brake specific fuel consumption (BSFC). Pilot injection cases exhibited slightly higher smoke levels than single injection cases but had similar NOx levels, while the single injection cases exhibited slightly better BSFC. The start-of-injection (SOI) of the pilot was varied while holding the main SOI constant and the effect on emissions was found to be small compared to changes resulting from varying the main injection timing. Interestingly, the point of autoignition of the pilot was found to occur at a nearly constant crank angle regardless of pilot injection timing (for early injection timings) indicating that the ignition delay of the pilot is a chemical delay and not a physical (mixing) one. As the pilot timing was advanced the mixture became overmixed, and an increase of over 50 percent in the unburned hydrocarbon emissions was observed at the most advanced pilot injection timing.

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.

A numerical study on soot formation and oxidation for a direct injection diesel engine

2003 ◽  
Vol 217 (5) ◽  
pp. 403-413 ◽  
Author(s):  
N Sung ◽  
S Lee ◽  
H Kim ◽  
B Kim
Keyword(s):  
Diesel Engine ◽  
Combustion Temperature ◽  
Soot Formation ◽  
Direct Injection ◽  
Soot Oxidation ◽  
Operating Conditions ◽  
Injection Timing ◽  
Mixture Ratio ◽  
Soot Particles ◽  
Carbon Radicals

A numerical cycle model is developed to investigate the soot production in a direct injection (DI) diesel engine. The Surovikin and Fusco models for soot formation and the Nagle model for soot oxidation are used with the KIVA-3V code. In the Surovikin model, carbon radicals are produced from pyrolysis of fuel and soot particles grow through collisions with fuel molecules. In the Fusco model, the carbon radicals and acetylene are formed from pyrolysis of fuel. There, acetylene works for the growth of soot particles. From investigation of the e. ects of the operating conditions on soot formation and oxidation, it is found that soot formation is mainly governed by fuel concentration and combustion temperature and soot oxidation is more dependent on combustion temperature. The air-fuel ratio a. ects soot formation more than injection timing. For a stoichiometric mixture ratio, soot formation is increased because of the high combustion temperature.

A Study on an Automatically Variable Intake Exhaust Injection Timing Turbocharging System for Diesel Engines

2010 ◽  
Vol 132 (5) ◽  
Author(s):  
Shiyou Yang ◽  
Kangyao Deng ◽  
Yi Cui ◽  
Hongzhong Gu
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
High Speed ◽  
Control Mechanism ◽  
Operating Conditions ◽  
Combustion Model ◽  
Injection Timing ◽  
Low Speed ◽  
Turbocharging System ◽  
High Torque

A new turbocharging system, named automatically variable intake exhaust injection timing (AVIEIT), is proposed. Its main purpose is to improve the performance of low-speed high torque operating conditions and improve the economy of high-speed operating conditions for high-speed supercharged intercooled diesel engines. The principle of the AVIEIT turbocharging system is presented. A control mechanism for the proposed AVIEIT system used for a truck diesel engine is introduced. An engine simulation code has been developed. In this code, a zero-dimensional in-cylinder combustion model, a one-dimensional finite volume method-total variation diminishing model for unsteady gas flow in the intake and exhaust manifolds, and a turbocharger model are used. The developed code is used to simulate the performances of diesel engines using the AVIEIT system. Simulations of a military use diesel engine “12V150” and a truck diesel engine “D6114” using the AVIEIT system have been performed. Simulation results show that the in-cylinder charge air amount of the diesel engine with the AVIEIT system is increased at low-speed high torque operating conditions, and the fuel economy is improved at high-speed operating conditions. In order to test the idea of the AVIEIT system, an experiment on a truck diesel engine D6114 equipped with an AVIEIT control mechanism has been finished. The experiment results show that the AVIEIT system can improve the economy of high-speed operating conditions. Both the simulation and experiment results suggest that the AVIEIT system has the potential to replace the waste-gate and variable geometry turbocharger turbocharging systems.

Simultaneous High-Speed Imaging of Fuel Spray, Combustion Luminosity, and Soot Luminosity in a Spray-Guided Direct Injection Engine With Different Multi-Hole Fuel Injectors

2013 ◽  
Author(s):  
Ming Zhang ◽  
Michael C. Drake ◽  
Kevin Peterson
Keyword(s):  
High Speed ◽  
Soot Formation ◽  
Direct Injection ◽  
Fuel Spray ◽  
Exhaust Emission ◽  
Injection Timing ◽  
Gaseous Emissions ◽  
High Speed Imaging ◽  
Fuel Injectors ◽  
Spray Structure

Eight different multi-hole fuel injectors with nominally the same exterior geometry (8-hole, 60 degree circular symmetric spray pattern) but different levels of development (Generation I and Generation II), length-to-diameter (L/D) ratios (1.4 to 2.4), and manufacturing processes (EDM vs. laser drilled) are compared in a spray-guided, spark-ignition direct injection (SG-SIDI) single-cylinder optical engine. In-cylinder pressure measurements and exhaust emission measurements quantified effects of different injectors on combustion and emissions. Crank-angle-resolved white-light spray imaging and simultaneous flame and soot visualization quantified variations in spray structure, combustion propagation, and soot formation and oxidation. At a single operating condition (2000rpm, 95kPa inlet pressure, 90°C engine temperature, end of injection timing (EOI) @ 36 BTDC, spark advance (SA) @ 36 BTDC, 8.1mg/injection), all eight injectors have nearly the same IMEP (about 270kPa) and engine-out gaseous emissions. Experiments show that laser drilled injectors with lower L/D ratios (L/D = 1.4–2.0) have a totally collapsed fuel spray structure, a more penetrating liquid spray with severe fuel impingement on the piston, and rapidly-forming soot deposits on the piston. The collapsed, more compact fuel spray vaporized more slowly and the resulting rich zones led to strong soot luminosity. In contrast, the laser drilled injector with the highest L/D ratio (2.4) and the two EDM injectors (Generation I and Generation II with L/D = 2.0) show 8 distinct spray plumes, less fuel impingement, and much less soot emission intensity. Image analysis tools developed in Matlab were used to characterize the flame propagation and soot formation processes.

Gasoline and E85 Combustion Visualization and Particulate Matter Emission in a Production SIDI Engine With Optical Access

2013 ◽  
Author(s):  
Po-I Lee ◽  
Xiaoce Feng ◽  
Ming-Chia Lai
Keyword(s):  
Diffusion Flame ◽  
High Speed ◽  
Particle Number ◽  
Total Concentration ◽  
Direct Injection ◽  
Cylinder Liner ◽  
Operating Conditions ◽  
Coolant Temperature ◽  
Injection Timing ◽  
Optical Access

The present study analyzes the relationship of diffusion flame and PM emission of pure gasoline (E0) and E85 in a spark-ignited direct injection engine at low coolant temperature with optical access on one side of combustion chamber for high speed visualization. Different operating conditions including injection timing, ignition timing, and air-fuel ratio (lambda) with two throttle positions (high and low load) are experimented with a high speed FTIR and an Engine Exhaust Particle Sizer (EEPS) to measure the engine-out emissions. The results show that fuel types and injection timing strongly impact particle size distribution, total concentration, and total mass of PM emission due to piston or cylinder liner wall-wetting. It is concluded that both E0 and E85 present diffusion flame with early injection timing, and the existence of diffusion flame seen in the images corresponds to higher particle mass; however, it does not necessarily represent higher particle number, which is also fuel dependent. In certain conditions, PM emission of E85 could be higher in terms of particle number.

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

2007 ◽  
Vol 130 (1) ◽  
Author(s):  
T. Cerri ◽  
A. Onorati ◽  
E. Mattarelli
Keyword(s):  
Diesel Engine ◽  
High Speed ◽  
Fuel Injection ◽  
Direct Injection ◽  
Combustion Process ◽  
Numerical Approach ◽  
Operating Conditions ◽  
Combustion Model ◽  
Full Load ◽  
Partial Load

The paper analyzes the operations of a small high speed direct injection (HSDI) turbocharged diesel engine by means of a parallel experimental and computational investigation. As far as the numerical approach is concerned, an in-house 1D research code for the simulation of the whole engine system has been enhanced by the introduction of a multizone quasi-dimensional combustion model, tailored for multijet direct injection diesel engines. This model takes into account the most relevant issues of the combustion process: spray development, air-fuel mixing, ignition, and formation of the main pollutant species (nitrogen oxide and particulate). The prediction of the spray basic patterns requires 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 to the analysis of some operating conditions at partial load, without any change to the calibration parameters. Still, the numerical simulation provided results that qualitatively agree with experiments.

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