A Numerical Study of the Effect of Multi-Injection Strategy on NOx Reduction in DI Diesel Engines

2005 ◽  
Author(s):  
Yan Wang ◽  
Chao Zhang ◽  
Jin Jiang
Keyword(s):  
Diesel Engines ◽  
Internal Combustion Engines ◽  
Fuel Injection ◽  
Numerical Study ◽  
Fuel Efficiency ◽  
Nox Reduction ◽  
Nox Emission ◽  
Production Model ◽  
Combustion Model ◽  
Injection Strategy

Diesel engines are becoming more and more popular as a power source for transportation and industry utility because of their better fuel efficiency over gasoline engines. At the same time, more and more stringent emission regulations on internal combustion engines have been used by governments all over the world. NOx emission control has become one of the biggest challenges in the design of Diesel engines. Previous experiments and simulations have shown that the multi-fuel-injection strategy can potentially reduce NOx emission in Diesel engines. In this study, more detailed numerical simulations have been conducted for up to 5 split fuel injections as compared to the conventional single fuel injection strategy to explore the effect of multi-fuel-injection on NOx reduction. KIVA-3V release 2, a multi-dimensional computational code employing combustion model, turbulence model, spray model and NOx production model, has been used in the numerical simulation. The combinations of multi-fuel-injection strategy with EGR (Exhaust Gas Recirculation) technique and multi-hole injectors are investigated as well. The results of this investigation have demonstrated that the use of the multi-fuel-injection strategy can effectively reduce the NOx emission in Diesel engines. Combined with other NOx reduction techniques, multi-fuel-injection strategy is a very promising way to make modern Diesel engines comply with the ever-stringent emission targets.

Fuel Efficiency – Challenges and Innovations in Emulsified Fuel Technology

2015 ◽  
Author(s):  
Jerry Ng ◽  
Kaisa Honkanen
Keyword(s):  
Diesel Engines ◽  
Fuel Injection ◽  
Fuel Efficiency ◽  
Combustion Efficiency ◽  
Secondary Atomization ◽  
Emulsified Fuel ◽  
Main Challenge ◽  
Marine Diesel ◽  
Initial Fuel ◽  
Fuel Technology

Emulsified fuel technology has been developed since the early 1980’s to the improve combustion efficiency of marine diesel engines by creating a secondary atomization effect after the initial fuel injection. The main challenge is to measure the improved sfoc of ships accurately and reliably. This paper presents a proposed method to measure the sfoc accurately and reliably to the order of 1%. Electronic governor also poses new challenge to measuring the sfoc of ships burning emulsified fuel. Meanwhile, fuel types supplied to ship owners are of increased varying properties although still complying to ISO8217 standard. This paper describes the innovations in emulsified fuel technology that were developed to meet these challenges.

scholarly journals Possibilities of Simultaneous In-Cylinder Reduction of Soot andNOxEmissions for Diesel Engines with Direct Injection

2008 ◽  
Vol 2008 ◽  
pp. 1-13 ◽  
Author(s):  
U. Wagner ◽  
P. Eckert ◽  
U. Spicher
Keyword(s):  
Nitrogen Oxide ◽  
Diesel Engines ◽  
Fuel Injection ◽  
Soot Formation ◽  
Soot Oxidation ◽  
The Other ◽  
Injection System ◽  
Nitrogen Oxide Emissions ◽  
Injection Strategy ◽  
Soot Emissions

Up to now, diesel engines with direct fuel injection are the propulsion systems with the highest efficiency for mobile applications. Future targets in reducingCO2-emissions with regard to global warming effects can be met with the help of these engines. A major disadvantage of diesel engines is the high soot and nitrogen oxide emissions which cannot be reduced completely with only engine measures today. The present paper describes two different possibilities for the simultaneous in-cylinder reduction of soot and nitrogen oxide emissions. One possibility is the optimization of the injection process with a new injection strategy the other one is the use of water diesel emulsions with the conventional injection system. The new injection strategy for this experimental part of the study overcomes the problem of increased soot emissions with pilot injection by separating the injections spatially and therefore on the one hand reduces the soot formation during the early stages of the combustion and on the other hand increases the soot oxidation later during the combustion. Another method to reduce the emissions is the introduction of water into the combustion chamber. Emulsions of water and fuel offer the potential to simultaneously reduceNOxand soot emissions while maintaining a high-thermal efficiency. This article presents a theoretical investigation of the use of fuel-water emulsions in DI-Diesel engines. The numerical simulations are carried out with the 3D-CFD code KIVA3V. The use of different water diesel emulsions is investigated and assessed with the numerical model.

Water Addition in Diesel Engine Intake for NOx Reduction: Comparison of Modeling and Experiments

2003 ◽  
Author(s):  
Bhaskar Tamma ◽  
Juan Carlos Alvarez ◽  
Aaron J. Simon
Keyword(s):  
Diesel Engine ◽  
Fuel Efficiency ◽  
Nox Reduction ◽  
Engine Performance ◽  
Thermodynamic Cycle ◽  
Nox Emission ◽  
Water Addition ◽  
Predictive Tool ◽  
Fuel Flow ◽  
Influence Of Water

Reduction in emissions, especially NOx has been the main study of various engine researchers in the light of stringent emission norms. To reduce the time and cost involved in testing these technologies, engine thermodynamic cycle predictive tools are used. The present work uses one such predictive tool (GT Power from Gamma Technologies) for predicting the influence of water addition in a turbocharged 6-cylinder diesel engine intake on engine performance and NOx emissions. The experiments for comparison with modeling included the introduction of liquid water in the engine intake stream, between the compressor and intercooler ranging from 0 to 100% of fuel flow rate. NOx emission reduced linearly with water addition with reduction of 63% with less than 1% penalty on fuel efficiency at 100% water addition. The GT Power model predicted the performance within 5% of experimental data and NOx emission within 10% of the experiments.

A Control Oriented SI and HCCI Hybrid Combustion Model for Internal Combustion Engines

2010 ◽  
Author(s):  
Xiaojian Yang ◽  
Guoming G. Zhu ◽  
Zongxuan Sun
Keyword(s):  
Steady State ◽  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Fuel Efficiency ◽  
Combustion Process ◽  
Internal Combustion ◽  
Mean Value ◽  
Combustion Model ◽  
Zone Model ◽  
Transient Control

The combustion mode transition between SI (spark ignited) and HCCI (Homogeneously Charged Compression Ignition) of an IC (Internal Combustion) engine is challenge due to the thermo inertia of residue gas; and model-based control becomes a necessity. This paper presents a control oriented two-zone model to describe the hybrid combustion that starts with SI combustion and ends with HCCI combustion. The gas respiration dynamics were modeled using mean-value approach and the combustion process was modeled using crank resolved method. The developed model was validated in an HIL (Hardware-In-the-Loop) simulation environment for both steady-state and transient operations in SI, HCCI, and SI-HCCI hybrid combustion modes through the exhaust valve timing control (recompression). Furthermore, cooled external EGR (exhaust gas re-circulation) was used to suppress engine knock and enhance the fuel efficiency. The simulation results also illustrates that the transient control parameters of hybrid combustion is quite different from these in steady state operation, indicating the need of a control oriented SI-HCCI hybrid combustion model for transient combustion control.

A Numerical Study of NOx Reduction for a DI Diesel Engine With Complex Geometry

2004 ◽  
Vol 126 (1) ◽  
pp. 13-20 ◽  
Author(s):  
Renshan Liu ◽  
Chao Zhang
Keyword(s):  
Diesel Engine ◽  
Thermal Efficiency ◽  
Fuel Injection ◽  
Complex Geometry ◽  
Numerical Study ◽  
Direct Injection ◽  
Nox Reduction ◽  
Geometrical Parameters ◽  
Injection Timing ◽  
Di Diesel Engine

A numerical study of NOx reduction for a Direct Injection (DI) Diesel engine with complex geometry, which includes intake/exhaust ports and moving valves, was carried out using the commercial computational fluid dynamics software KIVA-3v. The numerical simulations were conducted to investigate the effects of engine operating and geometrical parameters, including fuel injection timing, fuel injection duration, and piston bowl depth, on the NOx formation and the thermal efficiency of the DI Diesel engine. The tradeoff relationships between the reduction in NOx and the decrease in thermal efficiency were established.

Particle Number Emissions of Nonroad Diesel Engines of Various Ages

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Seppo Niemi ◽  
Krister Ekman ◽  
Pekka Nousiainen
Keyword(s):  
Diesel Engines ◽  
Particle Number ◽  
New Technologies ◽  
Fuel Injection ◽  
Nox Reduction ◽  
Particle Size Range ◽  
Diesel Particulate ◽  
Diesel Particulate Filters ◽  
Particulate Filters ◽  
Injection Pump

Over the last two decades, gaseous and particle mass emissions of new diesel engines have been reduced effectively and progressively in response to the emissions legislation and due to the applied new technologies. There is, however, increasing concern about whether the engine modifications, while improving combustion and reducing emissions, have increased the number emissions of ultrafine and nanoparticles. So far, emissions regulations have solely been based on particulate matter (PM) mass measurements, not on particle number. Nanoparticles, however, form a major part of the PM emissions, but they do not considerably contribute to the PM mass and cannot be seen as a problem, if only PM mass is determined. Therefore, there is increasing interest in expanding the scope of the regulations to also include particle number emissions, e.g., Euro VI for on-road engines. The PM number limit will also be enforced for nonroad engines slightly later. Thus, more information is required about the particle number emissions themselves, but also about the effects of the engine technology on them. Wall-flow diesel particulate filters reduce the particle number very effectively within the entire particle size range. Nevertheless, in order to keep the filter as small as possible and to lessen the need for regeneration, the engine-out PM number should also be minimized. If the diesel particulate filters (DPFs) could be left out or replaced by a simpler filter, there would be greater freedom of space utilization or cost savings in many nonroad applications. This might be realized in installations where the engine is tuned at high raw NOx and a selective catalytic reduction (SCR) system is adopted for NOx reduction. However, it is not self-evident that new engine technologies would reduce the PM number emissions sufficiently. In this study, particle number emissions were analyzed in several nonroad diesel engines, representing different engine generations and exploiting different emissions reduction technologies: four- or two-valve heads, exhaust gas recirculation, different injection pressures and strategies, etc. All engines were turbocharged, intercooled, direct-injection nonroad diesel engines. Most engines used common-rail fuel injection technology. Comparisons were, however, also performed with engines utilizing either a distributor-type or an in-line fuel injection pump to see the long-term development of the particle number emissions. In this paper, the PM number emissions of nine nonroad diesel engines are presented and compared. Gaseous exhaust emissions and fuel consumption figures are also provided.

Direct Water Injection to Improve Diesel Spray Combustion

2003 ◽  
Author(s):  
Koji Takasaki ◽  
Tatsuo Takaishi ◽  
Hiroyuki Ishida ◽  
Keijirou Tayama
Keyword(s):  
Diesel Engines ◽  
High Speed ◽  
Fuel Injection ◽  
Nox Reduction ◽  
Water Injection ◽  
Injection Pressure ◽  
Injection System ◽  
Injection Hole ◽  
Low Speed ◽  
Direct Water Injection

Now, it is essential to apply some measures for NOx reduction to low-speed diesel engines emitting much more NOx than high-speed engines. At the same time PM emission must be reduced especially when bunker fuel or heavy fuel is burned. This paper describes the applications of SFWI (Stratified Fuel Water Injection) system and DWI (Direct Water Injection) system to large sized diesel engines to reduce NOx and PM emission. SFWI system makes it possible to inject water during fuel injection from the same nozzle hole without mixing the liquids. DWI system injects water with high injection pressure from the other injection hole than the fuel injection hole into the combustion chamber directly. For testing both the systems, a 2-stroke-cycle low-speed test engine was used.

scholarly journals Modeling of pulverized coal combustion for in-furnace NOx reduction and flame control

2017 ◽  
Vol 21 (suppl. 3) ◽  
pp. 597-615 ◽  
Author(s):  
Srdjan Belosevic ◽  
Ivan Tomanovic ◽  
Nenad Crnomarkovic ◽  
Aleksandar Milicevic
Keyword(s):  
Coal Combustion ◽  
Numerical Study ◽  
Nox Reduction ◽  
Combustion Process ◽  
Pulverized Coal ◽  
Operating Conditions ◽  
Nox Emission ◽  
Differential Model ◽  
No Formation ◽  
Turbulent Reactive Flows

A cost-effective reduction of NOx emission from utility boilers firing pulverized coal can be achieved by means of combustion modifications in the furnace. It is also essential to provide the pulverized coal diffusion flame control. Mathematical modeling is regularly used for analysis and optimization of complex turbulent reactive flows and mutually dependent processes in coal combustion furnaces. In the numerical study, predictions were performed by an in-house developed comprehensive three-dimensional differential model of flow, combustion and heat/mass transfer with submodel of the fuel- and thermal-NO formation/ destruction reactions. Influence of various operating conditions in the case-study utility boiler tangentially fired furnace, such as distribution of both the fuel and the combustion air over the burners and tiers, fuel-bound nitrogen content and grinding fineness of coal were investigated individually and in combination. Mechanisms of NO formation and depletion were found to be strongly affected by flow, temperature and gas mixture components concentration fields. Proper modifications of combustion process can provide more than 30% of the NOx emission abatement, approaching the corresponding emission limits, with simultaneous control of the flame geometry and position within the furnace. This kind of complex numerical experiments provides conditions for improvements of the power plant furnaces exploitation, with respect to high efficiency, operation flexibility and low emission.

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