Observer Based Oxygen Fraction Estimation for a Dual-Loop EGR Diesel Engine Fueled With Biodiesel Blends

2013 ◽  
Author(s):  
Junfeng Zhao ◽  
Junmin Wang
Keyword(s):  
Oxygen Content ◽  
Oxygen Concentration ◽  
Control Unit ◽  
Intake Manifold ◽  
Engine Model ◽  
Oxygen Fraction ◽  
Emission Effect ◽  
Physical Insight ◽  
Gas Recirculation ◽  
Insight Into

This paper investigates the influence of biodiesel on the effectiveness of exhaust gas recirculation (EGR) in modern Diesel engines equipped with dual-loop EGR systems. Intake manifold oxygen fraction, which is an important factor for both combustion and emissions, is selected as a new reference for evaluating the equivalent EGR level instead of EGR ratio. A Luenberger-like observer for the oxygen fraction is designed based on the dynamic model of the air-path loop with consideration of the existence of oxygen content in the fuel. The convergence of the observer is proved with the assistance of some physical insight into the engine system. The performance of the observer is validated on a high-fidelity engine model built in GT-Power. The results show that when the same amount of fuel is injected, there is an increase in the exhaust oxygen concentration for biodiesel as oxygen content in fuel increases. Then the higher exhaust oxygen concentration leads to an increase in the intake manifold oxygen fraction, since the engine control unit (ECU) commanded EGR valve angles are constant across different fuels. This real-time oxygen fraction estimation approach is potentially useful for mitigating the biodiesel NO x emission effect.

A Dual-Loop EGR Engine Air-Path Oxygen Concentration Model With Time-Varying Transport Delays

2013 ◽  
Author(s):  
Xiangrui Zeng ◽  
Junmin Wang
Keyword(s):  
Oxygen Concentration ◽  
Dynamic Models ◽  
Operating Conditions ◽  
High Fidelity ◽  
Exhaust Gas ◽  
Time Varying ◽  
Transport Delay ◽  
Engine Model ◽  
Gas Recirculation ◽  
Transient Operations

Dual-loop exhaust gas recirculation (EGR) systems can provide control authorities for adjusting the engine in-cylinder gas conditions. However, the transport delay in the EGR air-path makes some simple oxygen concentration dynamic models perform poorly under the transient operating conditions. In this paper, a dual-loop EGR air-path oxygen concentration model considering the time-varying transport delays is developed and a method to calculate the delay time based on the continuity of gas velocity is presented. Simulation validations using a high-fidelity GT-Power 1-D computational engine model show that the developed model can capture the oxygen concentration dynamics during both steady-state and transient operations.

scholarly journals The influence of non-cooled exhaust gas recirculation on the diesel engine parameters

2017 ◽  
Vol 171 (4) ◽  
pp. 269-273
Author(s):  
Jerzy CISEK
Keyword(s):  
Diesel Engine ◽  
Control Unit ◽  
Energy Performance ◽  
Intake Manifold ◽  
Total Efficiency ◽  
Exhaust Gas ◽  
Engine Torque ◽  
Exhaust Gases ◽  
Start Of Injection ◽  
Gas Recirculation

This paper presents the results of the diesel engine research on the energy performance, components of exhaust gases and smoke and parameters related to the supply system for VW 1.9 TDI working in 2 modes: with standard, non-cooled EGR system, and without this system. All of measurements were carried out on the some engine speed – 2000 rpm (speed of maximum engine torque) and various engine loads. It was found that the serial engine control unit switches the EGR system off above 150 Nm engine load (Momax = 295 Nm). In this range of load the engine running with EGR is characterized by higher fuel consumption (lower total efficiency) ca. 5%, compared with engine without EGR. Concentration of NOx in exhaust gases was lower up to 45% but, at the same time, exhaust gas smoke and concentration of carbon oxides were strongly increasing. It can be seen that EGR system increases the temperature (up to 110oC) and changes the composition of air-exhaust gas in the intake manifold. One of reason of this fact is self-changing start of injection. Additional effect of EGR is lower air pressure behind turbocharger, because the flow of exhaust gases (into EGR) is taken before the

Control-Oriented Dynamic Models for In-Cylinder Conditions of Multi-Cylinder Diesel Engines

2010 ◽  
Author(s):  
Fengjun Yan ◽  
Junmin Wang
Keyword(s):  
Diesel Engines ◽  
Dynamic Models ◽  
Gas Temperature ◽  
Engine Model ◽  
Oxygen Fraction ◽  
Advanced Combustion ◽  
Engine Combustion ◽  
Gas Recirculation ◽  
Very High ◽  
Physical Principles

This paper presents control-oriented models, describing the dynamics of the in-cylinder conditions (ICCs) at intake valve closing (IVC), for multi-cylinder Diesel engines. Such models are based on multi-cylinder Diesel engines equipped with dual-loop exhaust gas recirculation (EGR) systems. As the thermodynamic boundary conditions for Diesel engine combustion, ICCs at IVC play critical roles for controlling combustion, particularly advanced combustion modes whose sensitivities to ICCs are very high. Grounded in physical principles, control-oriented ICC dynamic models were developed to describe the multi-cylinder characteristic and the coupling effects among the ICC quantities (i.e. in-cylinder gas mass, gas temperature, and oxygen fraction at IVC). The effectiveness of the developed control-oriented model was validated by comparing with a high-fidelity, 1-D computational, GT-Power engine model.

scholarly journals Calculation of Intake Oxygen Concentration through Intake CO2 Measurement and Evaluation of Its Effect on Nitrogen Oxide Prediction Accuracy in a Heavy-Duty Diesel Engine

Energies ◽  
2022 ◽  
Vol 15 (1) ◽  
pp. 342
Author(s):  
Roberto Finesso ◽  
Omar Marello
Keyword(s):  
Diesel Engine ◽  
Oxygen Concentration ◽  
Control Unit ◽  
Absolute Error ◽  
Operating Conditions ◽  
Intake Manifold ◽  
Heavy Duty ◽  
Input Quantity ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

A new procedure, based on measurement of intake CO2 concentration and ambient humidity was developed and assessed in this study for different diesel engines in order to evaluate the oxygen concentration in the intake manifold. Steady-state and transient datasets were used for this purpose. The method is very fast to implement since it does not require any tuning procedure and it involves just one engine-related input quantity. Moreover, its accuracy is very high since it was found that the absolute error between the measured and predicted intake O2 levels is in the ±0.15% range. The method was applied to verify the performance of a previously developed NOx model under transient operating conditions. This model had previously been adopted by the authors during the IMPERIUM H2020 EU project to set up a model-based controller for a heavy-duty diesel engine. The performance of the NOx model was evaluated considering two cases in which the intake O2 concentration is either derived from engine-control unit sub-models or from the newly developed method. It was found that a significant improvement in NOx model accuracy is obtained in the latter case, and this allowed the previously developed NOx model to be further validated under transient operating conditions.

scholarly journals Adaptive Air Charge Estimation for Turbocharged Diesel Engines Without Exhaust Gas Recirculation

2004 ◽  
Vol 126 (3) ◽  
pp. 633-643 ◽  
Author(s):  
Ove F. Storset ◽  
Anna G. Stefanopoulou ◽  
Roy Smith
Keyword(s):  
Diesel Engines ◽  
Exhaust Gas Recirculation ◽  
Mean Value ◽  
Adaptive Observer ◽  
Intake Manifold ◽  
Exhaust Gas ◽  
Engine Model ◽  
Intake Manifold Pressure ◽  
Gas Recirculation ◽  
Better Than

The paper presents an adaptive observer for in-cylinder air charge estimation for turbocharged diesel engines without exhaust gas recirculation (EGR). We assess the observability of the mean value engine model when the intake manifold pressure and the compressor flow are measured, and the performance of the observer is compared to existing schemes analytically and with limited simulations. Specifically, it is shown that the designed observer performs better than the conventional schemes during fast step changes in engine fueling level, eventhough it uses a simple but time varying parameterization of the volumetric efficiency. Furthermore, the estimate is less sensitive to changes in engine parameters than the existing schemes.

scholarly journals Design of a Novel Miniaturized Frequency Selective Surface Based on 2.5-Dimensional Jerusalem Cross for 5G Applications

2018 ◽  
Vol 2018 ◽  
pp. 1-6 ◽  
Author(s):  
Peng Zhao ◽  
Yihang Zhang ◽  
Rongrong Sun ◽  
Wen-Sheng Zhao ◽  
Yue Hu ◽  
...  
Keyword(s):  
Resonant Frequency ◽  
Equivalent Circuit ◽  
Equivalent Circuit Model ◽  
Frequency Selective Surface ◽  
Size Reduction ◽  
Two Dimensional ◽  
Physical Insight ◽  
Frequency Selective ◽  
Significant Size ◽  
Insight Into

A compact frequency selective surface (FSS) for 5G applications has been designed based on 2.5-dimensional Jerusalem cross. The proposed element consists of two main parts: the successive segments of the metal traces placed alternately on the two surfaces of the substrate and the vertical vias connecting traces. Compared with previous published two-dimensional miniaturized elements, the transmission curves indicate a significant size reduction (1/26 wavelengths at the resonant frequency) and exhibit good angular and polarization stabilities. Furthermore, a general equivalent circuit model is established to provide direct physical insight into the operating principle of this FSS. A prototype of the proposed FSS has been fabricated and measured, and the results validate this design.

Endwall Blockage in Axial Compressors

1999 ◽  
Vol 121 (3) ◽  
pp. 499-509 ◽  
Author(s):  
S. A. Khalid ◽  
A. S. Khalsa ◽  
I. A. Waitz ◽  
C. S. Tan ◽  
E. M. Greitzer ◽  
...  
Keyword(s):  
Tip Clearance ◽  
Design Parameters ◽  
Tip Clearance Flow ◽  
Axial Compressors ◽  
Clearance Flow ◽  
Flow Features ◽  
Physical Insight ◽  
Level Loading ◽  
Stagger Angle ◽  
Insight Into

This paper presents a new methodology for quantifying compressor endwall blockage and an approach, using this quantification, for defining the links between design parameters, flow conditions, and the growth of blockage due to tip clearance flow. Numerical simulations, measurements in a low-speed compressor, and measurements in a wind tunnel designed to simulate a compressor clearance flow are used to assess the approach. The analysis thus developed allows predictions of endwall blockage associated with variations in tip clearance, blade stagger angle, inlet boundary layer thickness, loading level, loading profile, solidity, and clearance jet total pressure. The estimates provided by this simplified method capture the trends in blockage with changes in design parameters to within 10 percent. More importantly, however, the method provides physical insight into, and thus guidance for control of, the flow features and phenomena responsible for compressor endwall blockage generation.

Physical Insight into Self-heating Induced Performance Degradation in RingFET

Silicon ◽  
2021 ◽  
Author(s):  
Sahil Singh ◽  
P. S. T. N. Srinivas ◽  
Arun Kumar ◽  
Pramod Kumar Tiwari
Keyword(s):  
Performance Degradation ◽  
Self Heating ◽  
Physical Insight ◽  
Insight Into

Numerical and Experimental Study on the Impact of Mild Cold EGR on Exhaust Emissions in a Biodiesel Fueled Diesel Engine

2021 ◽  
Author(s):  
Alex Oliveira ◽  
Junfeng Yang ◽  
Jose Sodre
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Exhaust Emissions ◽  
Pollutant Emissions ◽  
Cylinder Pressure ◽  
Nox Formation ◽  
Ratio Distribution ◽  
Engine Model ◽  
Gas Recirculation ◽  
The Impact

Abstract This work evaluated the effect of cooled exhaust gas recirculation (EGR) on fuel consumption and pollutant emissions from a diesel engine fueled with B8 (a blend of biodiesel and Diesel 8:92%% by volume), experimentally and numerically. Experiments were carried out on a Diesel power generator with varying loads from 5 kW to 35 kW and 10% of cold EGR ratio. Exhaust emissions (e.g. THC, NOX, CO etc.) were measured and evaluated. The results showed mild EGR and low biodiesel content have minor impact of engine specific fuel consumption, fuel conversion efficiency and in-cylinder pressure. Meanwhile, the combination of EGR and biodiesel reduced THC and NOX up to 52% and 59%, which shows promising effect on overcoming the PM-NOX trade-off from diesel engine. A 3D CFD engine model incorporated with detailed biodiesel combustion kinetics and NOx formation kinetics was validated against measured in-cylinder pressure, temperature and engine-out NO emission from diesel engine. This valid model was then employed to investigate the in-cylinder temperature and equivalence ratio distribution that predominate NOx formation. The results showed that the reduction of NOx emission by EGR and biodiesel is obtained by a little reduction of the local in-cylinder temperature and, mainly, by creating comparatively rich combusting mixture.

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