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.

scholarly journals The effects of split direct injection on the operation of a tractor diesel engine fueled by biodiesel B20

2021 ◽  
Vol 286 ◽  
pp. 01006
Author(s):  
Andrei Laurentiu Niculae ◽  
Adnan Kadhim Rashid ◽  
Radu Chiriac
Keyword(s):  
Diesel Engine ◽  
Fuel Economy ◽  
Direct Injection ◽  
Pollutant Emissions ◽  
Combustion Model ◽  
Split Injection ◽  
Optimal Injection ◽  
Current Emission ◽  
Tractor Diesel ◽  
Injection Strategies

The use of biodiesel-diesel blends is a current solution to some important problems, such as the depletion of oil resources, global warming, and the pollutant emissions of smoke, carbon monoxide, and hydrocarbons of diesel engines. However, the use of this alternative fuel is characterized by a reduction in engine effective power and an increase in brake-specific fuel consumption and nitrogen oxide pollutant emissions. Using the AVL MCC zero-dimensional combustion model of the AVL BOOST simulation program, it was evaluated to what extent split injection strategies can improve the performance and fuel economy of a tractor diesel engine fuelled with biodiesel B20 at maximum brake torque condition considering noise and pollutant emissions limitation. Various pilot – main – post split injection strategies have been studied to establish the optimal injection characteristics in terms of performance and fuel economy. Subsequently, they have been adapted in terms of compliance with current emission standards. In this way, it has been emphasized that the split injection solution is a viable way to improve performance, economy, and pollutant emissions of a tractor diesel engine.

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.

Simulation of a Single Cylinder Diesel Engine Under Cold Start Conditions Using Simulink

2000 ◽  
Vol 123 (1) ◽  
pp. 117-124 ◽  
Author(s):  
H.-Q. Liu ◽  
N. G. Chalhoub ◽  
N. Henein
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Cold Start ◽  
Operating Conditions ◽  
Combustion Model ◽  
Nonlinear Dynamic Model ◽  
Single Cylinder ◽  
Engine Model ◽  
Simulink Model ◽  
Engine Components

A nonlinear dynamic model is developed in this study to simulate the overall performance of a naturally aspirated, single cylinder, four-stroke, direct injection diesel engine under cold start and fully warmed-up conditions. The model considers the filling and emptying processes of the cylinder, blowby, intake, and exhaust manifolds. A single zone combustion model is implemented and the heat transfer in the cylinder, intake, and exhaust manifolds are accounted for. Moreover, the derivations include the dynamics of the crank-slider mechanism and employ an empirical model to estimate the instantaneous frictional losses in different engine components. The formulation is coded in modular form whereby each module, which represents a single process in the engine, is introduced as a single block in an overall Simulink engine model. The numerical accuracy of the Simulink model is verified by comparing its results to those generated by integrating the engine formulation using IMSL stiff integration routines. The engine model is validated by the close match between the predicted and measured cylinder gas pressure and engine instantaneous speed under motoring, steady-state, and transient cold start operating conditions.

Effects of the Injection Parameters on the Emissions of a Heavy Duty Diesel Engine

2009 ◽  
Author(s):  
M. Yılmaz ◽  
M. Zafer Gul ◽  
Y. Yukselenturk ◽  
B. Akay ◽  
H. Koten
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Combustion Process ◽  
Design Parameters ◽  
Combustion Model ◽  
Particulate Emissions ◽  
Multiphase Model ◽  
Heavy Duty ◽  
Flow Development ◽  
Air Motion

It is estimated by the experts in the automotive industry that diesel engines on the transport market should increase within the years to come due to their high thermal efficiency coupled with low carbon dioxide (CO2) emissions, provided their nitrogen oxides (NOx) and particulate emissions are reduced. At present, adequate after-treatments, NOx and particulates matter (PM) traps are developed and industrialized with still concerns about fuel economy, robustness, sensitivity to fuel sulfur and cost because of their complex and sophisticated control strategy. New combustion processes focused on clean diesel combustion are investigated for their potential to achieve near zero particulate and NOx emissions. Their main drawbacks are increased level of unburned hydrocarbons (HC) and carbon monoxide (CO) emissions, combustion control at high load and limited operating range and power output. In this work, cold flow simulations for a single cylinder of a nine-liter (6 cylinder × 1.5 lt.) diesel engine have been performed to find out flow development and turbulence generation in the piston-cylinder assembly. In this study, the goal is to understand the flow field and the combustion process in order to be able to suggest some improvements on the in-cylinder design of an engine. Therefore combustion simulations of the engine have been performed to find out flow development and emission generation in the cylinder. Moreover, the interaction of air motion with high-pressure fuel spray injected directly into the cylinder has also been carried out. A Lagrangian multiphase model has been applied to the in-cylinder spray-air motion interaction in a heavy-duty CI engine under direct injection conditions. A comprehensive model for atomization of liquid sprays under high injection pressures has been employed. The combustion is modeled via a new combustion model ECFM-3Z (Extended Coherent Flame Model) developed at IFP. Finally, a calculation on an engine configuration with compression, spray injection and combustion in a direct injection Diesel engine is presented. Further investigation has also been performed in-cylinder design parameters in a DI diesel engine that result in low emissions by effect of high turbulence level. The results are widely in agreement qualitatively with the previous experimental and computational studies in the literature.

scholarly journals Experimental study of multiple pilot injection strategy in an automotive direct injection diesel engine

2018 ◽  
Vol 234 ◽  
pp. 03007
Author(s):  
Plamen Punov ◽  
Tsvetomir Gechev ◽  
Svetoslav Mihalkov ◽  
Pierre Podevin ◽  
Dalibor Barta
Keyword(s):  
Experimental Study ◽  
Diesel Engine ◽  
Diesel Engines ◽  
Direct Injection ◽  
Combustion Process ◽  
Injection Timing ◽  
Pilot Injection ◽  
Injection Strategy ◽  
Direct Injection Diesel Engine ◽  
Rate Of Heat Release

The pilot injection strategy is a widely used approach for reducing the noise of the combustion process in direct injection diesel engines. In the last generation of automotive diesel engines up to several pilot injections could occur to better control the rate of heat release (ROHR) in the cylinder as well as the pollutant formation. However, determination of the timing and duration for each pilot injection needs to be precisely optimised. In this paper an experimental study of the pilot injection strategy was conducted on a direct injection diesel engine. Single and double pilot injection strategy was studied. The engine rated power is 100 kW at 4000 rpm while the rated torque is 320 Nm at 2000 rpm. An engine operating point determined by the rotation speed of 1400 rpm and torque of 100 Nm was chosen. The pilot and pre-injection timing was widely varied in order to study the influence on the combustion process as well as on the fuel consumption.

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