A Phenomenological Model for Soot Formation and Oxidation in Direct-Injection Diesel Engines

1995 ◽  
Author(s):  
Xiaobin Li ◽  
James S. Wallace
Keyword(s):  
Diesel Engines ◽  
Phenomenological Model ◽  
Soot Formation ◽  
Direct Injection

A Phenomenological Model for Combustion and Emissions in Small Bore, High Speed, Direct Injection Diesel Engines

2005 ◽  
Author(s):  
N. A. Henein ◽  
I. P. Singh ◽  
L. Zhong ◽  
Y. Poonawala ◽  
J. Singh ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Phenomenological Model ◽  
High Speed ◽  
Gas Flow ◽  
Fuel Injection ◽  
Direct Injection ◽  
Injection System ◽  
Injection Process ◽  
Wide Range

This paper introduces a phenomenological model for the fuel distribution, combustion, and emissions formation in the small bore, high speed direct injection diesel engine. A differentiation is made between the conditions in large bore and small bore diesel engines, particularly regarding the fuel impingement on the walls and the swirl and squish gas flow components. The model considers the fuel injected prior to the development of the flame, fuel injected in the flame, fuel deposited on the walls and the last part of the fuel delivered at the end of the injection process. The model is based on experimental results obtained in a single-cylinder, 4-valve, direct-injection, four-stroke-cycle, water-cooled, diesel engine equipped with a common rail fuel injection system. The engine is supercharged with heated shop air, and the exhaust back pressure is adjusted to simulate actual turbo-charged diesel engine conditions. The experiments covered a wide range of injection pressures, EGR rates, injection timings and swirl ratios. Correlations and 2-D maps are developed to show the effect of combinations of the above parameters on engine out emissions. Emphasis is made on the nitric oxide and soot measured in Bosch Smoke Units (BSU).

Quasidimensional Modeling of Direct Injection Diesel Engine Nitric Oxide, Soot, and Unburned Hydrocarbon Emissions

2005 ◽  
Vol 128 (2) ◽  
pp. 388-396 ◽  
Author(s):  
Dohoy Jung ◽  
Dennis N. Assanis
Keyword(s):  
Nitric Oxide ◽  
Diesel Engine ◽  
Diesel Engines ◽  
Soot Formation ◽  
Direct Injection ◽  
Equation Model ◽  
Design Tool ◽  
Pollutant Emissions ◽  
Combustion Model ◽  
Cycle Simulation

In this study we report the development and validation of phenomenological models for predicting direct injection (DI) diesel engine emissions, including nitric oxide (NO), soot, and unburned hydrocarbons (HC), using a full engine cycle simulation. The cycle simulation developed earlier by the authors (D. Jung and D. N. Assanis, 2001, SAE Transactions: Journal of Engines, 2001-01-1246) features a quasidimensional, multizone, spray combustion model to account for transient spray evolution, fuel–air mixing, ignition and combustion. The Zeldovich mechanism is used for predicting NO emissions. Soot formation and oxidation is calculated with a semiempirical, two-rate equation model. Unburned HC emissions models account for three major HC sources in DI diesel engines: (1) leaned-out fuel during the ignition delay, (2) fuel yielded by the sac volume and nozzle hole, and (3) overpenetrated fuel. The emissions models have been validated against experimental data obtained from representative heavy-duty DI diesel engines. It is shown that the models can predict the emissions with reasonable accuracy. Following validation, the usefulness of the cycle simulation as a practical design tool is demonstrated with a case study of the effect of the discharge coefficient of the injector nozzle on pollutant emissions.

Experimental Validation for Control-Oriented Modeling of Multi-Cylinder HCCI Diesel Engines

2006 ◽  
Author(s):  
Marcello Canova ◽  
Shawn Midlam-Mohler ◽  
Yann Guezennec ◽  
Giorgio Rizzoni ◽  
Luca Garzarella ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Diesel Engines ◽  
Soot Formation ◽  
Direct Injection ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Injection System ◽  
Compression Ignition ◽  
Mixture Formation ◽  
Hcci Combustion

Homogeneous Charge Compression Ignition (HCCI) is a combustion process based on a lean, homogeneous, premixed charge reacting and burning uniformly throughout the mixture volume. This principle leads to a consistent decrease in NOx and PM emissions, while the combustion efficiency remains comparable to traditional Compression Ignition Direct Injection (CIDI) engines at low and mid-load operations. However, understanding and controlling the combustion process is still extremely difficult, as well as finding a proper method for the fuel introduction. A viable method consists of premixing the charge by applying a proper fuel atomization device in the intake port, thus decoupling the HCCI mixture formation from the traditional in-cylinder injection. This avoids the traditional drawbacks associated to external Diesel mixture preparation, such as high intake heating, low compression ratio, wall wetting, and soot formation. The system, previously developed and tested on a single-cylinder engine, has been successfully applied to multi-cylinder Diesel engine for automotive applications. Building on previous modeling and experimental work, the paper reports a detailed experimental analysis of HCCI combustion with external mixture formation. In the considered testing setup, the fuel atomizer has been applied to a four-cylinder turbo-charged Common Rail Diesel engine equipped with a cooled EGR system. In order to extend the knowledge on the process and to provide a large base of data for the identification of Control-Oriented Models, Diesel-fueled HCCI combustion has been characterized over different values of loads, EGR dilution and boost pressures. The data collected were then used for the validation of a HCCI Diesel engine model that was previously built for steady state and transient simulation and for control purposes. The experimental results obtained, especially considering the emission levels and efficiency, suggest that the technology developed for external mixture formation is a feasible upgrade for automotive Diesel engines without introducing additional design efforts or constraints on the DI combustion and injection system.

A multistage combustion model and soot formation model for direct-injection diesel engines

2002 ◽  
Vol 216 (6) ◽  
pp. 495-504 ◽  
Author(s):  
G J Micklow ◽  
W Gong
Keyword(s):  
Diesel Engines ◽  
Soot Formation ◽  
Direct Injection ◽  
Combustion Process ◽  
Oxidation Mechanism ◽  
Soot Oxidation ◽  
Premixed Combustion ◽  
Combustion Model ◽  
Diffusion Combustion ◽  
Soot Model

A multistage combustion model for diesel engines is presented in this paper. Three combustion stages, ignition of diesel, premixed combustion and diffusion combustion, are considered in the combustion process in a typical medium speed direct injection diesel engine. The transition from the ignition delay to the premixed combustion stage occurs when the highest temperature in the cylinder is beyond a critical value, and the transition from the premixed combustion model to the diffusion combustion model occurs when a calculated fraction of the premixed fuel is burned, which is determined from an empirical correlation based on the engine design and running conditions. Significant improvements in the predictions for in-cylinder pressure and heat release rate were achieved compared with previous models. A soot model based on the Hiroyasu soot formation mechanism and the Nagle and Strickland-Constable soot oxidation mechanism was implemented in a standard KIVA3V code. The effect of the OH radical in soot oxidation was also incorporated into the soot model. Computations show that OH plays an important role during the late combustion stage. Predicted soot and NOx were compared with measured values and a good agreement was achieved.

Effect of altitude conditions on combustion and performance of a turbocharged direct-injection diesel engine

2021 ◽  
pp. 095440702110262
Author(s):  
Zhentao Liu ◽  
Jinlong Liu
Keyword(s):  
Diesel Engine ◽  
High Altitude ◽  
Diesel Engines ◽  
Direct Injection ◽  
Pressure Rise ◽  
Ambient Conditions ◽  
Allowable Limit ◽  
Spray Formation ◽  
Direct Injection Diesel Engine ◽  
And Performance

Market globalization necessitates the development of heavy duty diesel engines that can operate at altitudes up to 5000 m without significant performance deterioration. But the current scenario is that existing studies on high altitude effects are still not sufficient or detailed enough to take effective measures. This study applied a single cylinder direct injection diesel engine with simulated boosting pressure to investigate the performance degradation at high altitude, with the aim of adding more knowledge to the literature. Such a research engine was conducted at constant speed and injection strategy but different ambient conditions from sea level to 5000 m in altitude. The results indicated the effects of altitude on engine combustion and performance can be summarized as two aspects. First comes the extended ignition delay at high altitude, which would raise the rate of pressure rise to a point that can exceed the maximum allowable limit and therefore shorten the engine lifespan. The other disadvantage of high-altitude operation is the reduced excess air ratio and gas density inside cylinder. Worsened spray formation and mixture preparation, together with insufficient and late oxidation, would result in reduced engine efficiency, increased emissions, and power loss. The combustion and performance deteriorations were noticeable when the engine was operated above 4000 m in altitude. All these findings support the need for further fundamental investigations of in-cylinder activities of diesel engines working at plateau regions.

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