NOx Reduction by Injection Control

Aoyama, Taro; Mizuta, Junichi; Oshima, Yujiro

doi:10.4271/900637

Cited by 25 publications

(7 citation statements)

References 14 publications

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“…Retarding the main injection timing reduces the ignition delay as the cylinder contents are already at a higher temperature and conditions are favourable for auto-ignition, hence there is effectively less pre-mixed combustion which results in less NOx. The effect of late injection is in limiting the spatial development of local zones of high temperature thereby lowering the average temperature within the combustion chamber (Aoyama et al 1990). Earlier studies show that retarding the main injection timing reduces the ignition delay which in turn reduces the amount of fuel prepared for the premixed phase of combustion leading to less NOx and more soot (He et al 2015;Tennison and Reitz 2001).…”

Section: Main Injection Timingmentioning

confidence: 99%

“…Another study highlighted that one could retard the main injection when using a pilot injection as the pilot combustion ensures shorter delay of the main injection fuel, and thereby reduce NOx without any BSFC penalty (Aoyama et al 1990). One study saw that NOx was found to be increasing till a certain advancement of pilot injection timing and after a certain CAD, further advancement reduced NOx, which highlights the importance of separation between pilot injection and main injection (Sharma et al 2010).…”

Section: Pilot Injectionmentioning

confidence: 99%

“…The advantage of using retarded injection timing with a pilot injection in reducing emissions was established in various studies (Aoyama et al 1990;Bakenhus and Reitz 1999;Shundoh et al 1992). The importance of pilot injection quantity, SOI of pilot and the separation between the pilot injection and the main injection on emissions has also been highlighted in several research works (Sharma et al 2010;Mobasheri et al 2011;Dürnholz et al 1994;Nishimura et al 1998;Sindhu et al 2017).…”

Section: Pilot Injectionmentioning

confidence: 99%

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Modeling and Simulation of Diesel Engines Using CFD and Its Applications in Optimizing Various In-Cylinder Techniques

Menon

Mittal

2021

Energy, Environment, and Sustainability

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A four-stroke IC engine cycle undergoes the following processesintake, compression, combustion, expansion and exhaust, which are governed by complex fluid dynamics, chemical kinetics and heat transfer phenomena and occur in milli/nanosecond timescales inside the engine cylinder making it difficult to visualize experimentally. A better understanding of the in-cylinder phenomena helps design better engines in terms of performance, fuel consumption and emissions. Optimization of the engine processes through physical testing can be time and cost intensive. CFD analysis helps visualize the various in-cylinder processes, analyze them better and evaluate various engine optimization parameters without having to test on an actual engine, hence it is comparatively effortless to do back-to-back comparisons to identify the effect of a single parameter, which reduces the engine development time and cost drastically. CFD analysis of Diesel engines is particularly useful since there are many in-cylinder optimization parameters in a diesel engine in comparison with a conventional gasoline engine, due to the direct injection and heterogeneous nature of combustion. This chapter aims to give an overview of the general methodology followed in performing CFD simulations in diesel engines towards the objective of enhancing the performance and minimizing the fuel consumption and emissions. Here a comprehensive coverage of the complete process of modeling and simulation is attempted, starting with the basic input data required, typical assumptions used, fundamental governing equations and discretization, model formulation, initial conditions, boundary conditions, model validation, various sub-models used and the analysis of results. The effect of in-cylinder techniques like combustion chamber geometry, injection timing, multiple injections and exhaust gas recirculation on performance and emissions is discussed through a brief review of published literature. It is hoped that the reader will get an insight into the procedure followed in diesel engine CFD analysis and some of its applications in the optimization through various in-cylinder techniques.

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Section: Main Injection Timingmentioning

confidence: 99%

Section: Pilot Injectionmentioning

confidence: 99%

Section: Pilot Injectionmentioning

confidence: 99%

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Modeling and Simulation of Diesel Engines Using CFD and Its Applications in Optimizing Various In-Cylinder Techniques

Menon

Mittal

2021

Energy, Environment, and Sustainability

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“…The control of NO x by means of the adjustment of the injection parameters represents an alternative solution. In particular, it is well known [24] that the injection timing is closely correlated to the in-cylinder peak temperatures and, therefore, to the thermal NO x formation, for a given EGR level. Therefore, a NO x control algorithms which, in addition to the adoption of conventional EGR, also adjusts the injection timing in real-time during engine operation, is potentially capable of guaranteeing a very accurate NO x control in transient conditions, also compensating for EGR deviations with respect to the desired levels.…”

Section: Introductionmentioning

confidence: 99%

Model-Based Control of Torque and Nitrogen Oxide Emissions in a Euro VI 3.0 L Diesel Engine through Rapid Prototyping

D’Ambrosio

Finesso

Hardy³

et al. 2021

Energies

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In the present paper, a model-based controller of engine torque and engine-out Nitrogen oxide (NOx) emissions, which was previously developed and tested by means of offline simulations, has been validated on a FPT F1C 3.0 L diesel engine by means of rapid prototyping. With reference to the previous version, a new NOx model has been implemented to improve robustness in terms of NOx prediction. The experimental tests have confirmed the basic functionality of the controller in transient conditions, over different load ramps at fixed engine speeds, over which the average RMSE (Root Mean Square Error) values for the control of NOx emissions were of the order of 55–90 ppm, while the average RMSE values for the control of brake mean effective pressure (BMEP) were of the order of 0.25–0.39 bar. However, the test results also highlighted the need for further improvements, especially concerning the effect of the engine thermal state on the NOx emissions in transient operation. Moreover, several aspects, such as the check of the computational time, the impact of the controller on other pollutant emissions, or on the long-term engine operations, will have to be evaluated in future studies in view of the controller implementation on the engine control unit.

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“…One of the methods currently used to control NO x and soot formation is the retardation of fuel injection [1,2], but this affects the engine power and fuel economy. Increasing the injection pressure, the number of fuel nozzle holes and air swirling can improve the fuel burning and counter this effect.…”

Section: Introductionmentioning

confidence: 99%

Prediction of the effect of injection parameters on NO_x emission and burning quality in the direct injection diesel engine using a modified multizone model

Salem

El-Bahnasy²,

Elbaz

1998

Proceedings of the Institution of Mechanical Engineers, Part D:

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Combustion process in a quiescent chamber diesel engine is modelled using a multizone model. This model divides the cylinder charge into two zones, namely the unburnt zone (surrounding air) and the burnt zone (fuel spray with entrained air). The burnt zone is subdivided into 16 concentric sprays, instead of only eight sprays as in previous work, each one with its own temperature and composition. Liquid fuel, fuel vapour, air and products of combustion are assumed to be present in each zone. Real gas relations are used to calculate the properties of the mixture while products of combustion are assumed to be in chemical equilibrium at local temperature. The extended Zeldovich mechanism is used to predict the NO x formation. The cylinder pressure, temperature, heat release rate, NO x rate and concentration are calculated. For different injection pressures, injection advance angles and different fuel orifice hole diameters, the results show that the model can predict the measured cylinder pressure with high accuracy but it predicts the measured heat release rate and NO x emission rate with moderate accuracy. In addition, the effect of injection parameters on the NO x emission and engine power is predicted and it has been shown that NO x emission can be reduced without noticeable loss of engine power. This can be done by appropriate choice of injection pressure, injection advance angle and fuel nozzle hole diameters. A cw heat transfer surface area (m 2 ) A ori orifice area (m 2 ) d inj nozzle diameter (m) D cw cylinder bore (m) C d discharge coefficient C pi specific heat of each combustion species (kJ=kg K) f m jet centre-line concentration (kg=m 3 ) h f specific enthalpy of fuel (kJ=kg) h u specific enthalpy of unburnt mixture (kJ=kg) H cw heat convection coefficient (kJ=m 2 ) i inj number of holes in injector L length scale (m) m ae air entrainment mass (kg) m b mass of burnt fuel (kg) m f rate of injected fuel (kg=s) m spray mass of instantaneous spray fuel (kg) m sur mass of instantaneous surrounding air (kg) m u mass of unburnt fuel (kg) n engine speed (r=min) NuNusselt number P pressure (Pa) q w heat transfer rate (kJ=m 2 ) Q f heat absorbed during heating and evaporation (kJ) Q rel released heat during combustion (kJ) r v compression ratio r 0 initial droplet radius (m) R j jet radius (m) s stroke (m) S penetration (m) t time (s) T a surrounding air temperature (K) T ign ignition temperature (K) T m mean charge temperature (K) T spray temperature of instantaneous spray (K) 427 The MS was

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NOx Reduction by Injection Control

Cited by 25 publications

References 14 publications

Modeling and Simulation of Diesel Engines Using CFD and Its Applications in Optimizing Various In-Cylinder Techniques

Modeling and Simulation of Diesel Engines Using CFD and Its Applications in Optimizing Various In-Cylinder Techniques

Model-Based Control of Torque and Nitrogen Oxide Emissions in a Euro VI 3.0 L Diesel Engine through Rapid Prototyping

Prediction of the effect of injection parameters on NO_x emission and burning quality in the direct injection diesel engine using a modified multizone model

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NOx Reduction by Injection Control

Cited by 25 publications

References 14 publications

Modeling and Simulation of Diesel Engines Using CFD and Its Applications in Optimizing Various In-Cylinder Techniques

Modeling and Simulation of Diesel Engines Using CFD and Its Applications in Optimizing Various In-Cylinder Techniques

Model-Based Control of Torque and Nitrogen Oxide Emissions in a Euro VI 3.0 L Diesel Engine through Rapid Prototyping

Prediction of the effect of injection parameters on NOx emission and burning quality in the direct injection diesel engine using a modified multizone model

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Product

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Prediction of the effect of injection parameters on NO_x emission and burning quality in the direct injection diesel engine using a modified multizone model