Comparison of Crankangle Based Ignition Timing Methods on an HCCI Engine

2010 ◽  
Author(s):  
Ahmad Ghazimirsaied ◽  
Mahdi Shahbakhti ◽  
Charles Robert Koch
Keyword(s):  
Heat Release ◽  
Operating Conditions ◽  
Main Stage ◽  
Cyclic Variation ◽  
Ignition Timing ◽  
Crank Angle ◽  
Pressure Trace ◽  
Engine Operating Condition ◽  
Start Of Combustion ◽  
Third Derivative

Autoignition timing of a mixture in Homogeneous Charge Compression Ignition (HCCI) is very dependant and sensitive to the engine operating condition. To characterize combustion timing, different crank angle dependant methods are used but these methods can exhibit inaccurate results at some operating conditions. In this paper, a criterion that divides the engine operating condition into two regions, low and high cyclic variations (unstable operation) is defined. Then, different crankangle based methods for determining the start of combustion inside the cylinder for each of the two regions are compared. The start and duration of combustion are compared for wide range of operating conditions and the relative merits of each method discussed. The methods for characterizing the start of combustion are: CA50 based on the total heat release; the start of combustion from the third derivative of the pressure trace with respect to crank angle; the start of combustion from the third derivative of the pressure trace with respect to crank angle with two limits; CA10 based on total heat release; CA10 based on peak of main stage of combustion. The last method is introduced in this paper and has advantages in terms of accuracy of ignition timing detection and correlation with the start of combustion particularly for high cyclic variation engine operation. A new criterion, defined as the ratio between peak of main stage and the sum of peak of main stage and cool flame stage of heat release, is introduced to more accurately identify the operating region of the engine. This criterion is used to understand the performance of each of those crank angle based methods. The performance of each of those methods is investigated for both the low cyclic variation and the high cyclic variation (unstable) region of the engine.

Determination of a most representative cycle from cylinder pressure ensembles via statistical method using distribution skewness

2021 ◽  
pp. 146808742110655
Author(s):  
Jorge Pulpeiro González ◽  
Carrie M Hall ◽  
Christopher P Kolodziej
Keyword(s):  
Statistical Method ◽  
Combustion Engine ◽  
Pressure Rise ◽  
Operating Conditions ◽  
Cylinder Pressure ◽  
Pressure Trace ◽  
Combustion Knock ◽  
Engine Operating Condition ◽  
Combustion Processes

In internal combustion engine research, cylinder pressure measurements provide valuable information about the underlying thermodynamic and combustion processes, and are typically collected in ensembles of several 100 traces. Although in some particular fields of combustion research all traces are analyzed, in most cases only one trace is studied because analyzing all the traces is impractical due to the large number of collected samples. Instead, an ensemble-averaged pressure trace is commonly calculated and used for analysis. However, this pressure trace is highly smoothed and dynamic information is lost during the averaging process. With the average trace, pressure rise rates are lower and pressure oscillations such as the ones resulting from combustion knock are lost. In this work, a statistical method was developed to determine the “most representative cycle,” which is the cycle from the ensemble that has the pressure trace most representative of the engine operating condition. Eleven characteristic parameters are computed from each pressure trace and probabilistic distributions are obtained for each of the parameters using all the traces in the ensemble. Finally, the most representative cycle is selected by means of a cost function minimization. The benefits of this method are illustrated using experimental data from four very different engine platforms, under four different combustion modes and over a range of operating conditions.

Model-Based Combustion Duration and Ignition Timing Prediction for Combustion Phasing Control of a Spark-Ignition Engine Using In-Cylinder Pressure Sensors

2019 ◽  
Author(s):  
Xin Wang ◽  
Amir Khameneian ◽  
Paul Dice ◽  
Bo Chen ◽  
Mahdi Shahbakhti ◽  
...  
Keyword(s):  
Pressure Sensors ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Combustion Model ◽  
Ignition Timing ◽  
Model Based ◽  
Crank Angle ◽  
Si Engines ◽  
Phasing Control

Abstract Combustion phasing, which can be defined as the crank angle of fifty percent mass fraction burned (CA50), is one of the most important parameters affecting engine efficiency, torque output, and emissions. In homogeneous spark-ignition (SI) engines, ignition timing control algorithms are typically map-based with several multipliers, which requires significant calibration efforts. This work presents a framework of model-based ignition timing prediction using a computationally efficient control-oriented combustion model for the purpose of real-time combustion phasing control. Burn duration from ignition timing to CA50 (ΔθIGN-CA50) on an individual cylinder cycle-by-cycle basis is predicted by the combustion model developed in this work. The model is based on the physics of turbulent flame propagation in SI engines and contains the most important control parameters, including ignition timing, variable valve timing, air-fuel ratio, and engine load mostly affected by combination of the throttle opening position and the previous three parameters. With 64 test points used for model calibration, the developed combustion model is shown to cover wide engine operating conditions, thereby significantly reducing the calibration effort. A Root Mean Square Error (RMSE) of 1.7 Crank Angle Degrees (CAD) and correlation coefficient (R2) of 0.95 illustrates the accuracy of the calibrated model. On-road vehicle testing data is used to evaluate the performance of the developed model-based burn duration and ignition timing algorithm. When comparing the model predicted burn duration and ignition timing with experimental data, 83% of the prediction error falls within ±3 CAD.

Determination of the Start and End of Combustion in a Direct Injection Diesel Engine Using the Apparent Heat Release Rate

2017 ◽  
Author(s):  
Joseph Gerard T. Reyes ◽  
Edwin N. Quiros
Keyword(s):  
Diesel Engine ◽  
Heat Release ◽  
Heat Release Rate ◽  
Release Rate ◽  
Direct Injection ◽  
Injection Timing ◽  
Fuel Injector ◽  
Direct Injection Diesel Engine ◽  
Crank Angle ◽  
Start Of Combustion

The combustion duration in an internal combustion engine is the period bounded by the engine crank angles known as the start of combustion (SOC) and end of combustion (EOC), respectively. This period is essential in analysis of combustion for the such as the production of exhaust emissions. For compression-ignition engines, such as diesel engines, several approaches were developed in order to approximate the crank angle for the start of combustion. These approaches utilized the curves of measured in-cylinder pressures and determining by inspection the crank angle where the slope is steep following a minimum value, indicating that combustion has begun. These pressure data may also be utilized together with the corresponding cylinder volumes to generate the apparent heat release rate (AHRR), which shows the trend of heat transfer of the gases enclosed in the engine cylinder. The start of combustion is then determined at the point where the value of the AHRR is minimum and followed by a rapid increase in value, whereas the EOC is at the crank angle where the AHRR attains a flat slope prior to the exhaust stroke of the engine. To verify the location of the SOC, injection line pressures and fuel injection timing are also used. This method was applied in an engine test bench using a four-cylinder common-rail direct injection diesel engine with a pressure transducer installed in the first cylinder. Injector line pressures and fuel injector voltage signals per engine cycle were also recorded and plotted. By analyzing the trends of this curves in line with the generated AHRR curves, the SOC may be readily determined.

Assessment of a Strategy for Optimum Control of Ignition Advance Angle

1988 ◽  
Vol 202 (1) ◽  
pp. 1-8 ◽  
Author(s):  
R S Quayle ◽  
S R Bhot
Keyword(s):  
Combustion Engine ◽  
Electronic System ◽  
Open Loop ◽  
Operating Conditions ◽  
Ignition Timing ◽  
System A ◽  
Engine Design ◽  
Peak Cylinder Pressure ◽  
Crank Angle ◽  
Inlet Manifold

The control of ignition timing in an internal combustion engine can improve fuel consumption. Electronic control implemented in software with a microprocessor has advantages over conventional mechanical systems. An open-loop electronic system, while incorporating an optimum profile against inlet manifold vacuum and speed, cannot readily adjust for wear. The optimum crank angle at which the peak cylinder pressure occurs has been found to be reasonably constant for a particular engine design irrespective of operating conditions. This paper presents a discussion of the use of this parameter as a measurand for a closed-loop ignition timing system. A discussion is presented of the control strategy used and results demonstrate the ability of the strategy to maintain constant the peak pressure position.

Experimental Investigation of Dual-Swirl Spray Flame in a Fuel Staged Optical Model Combustor With Laser Diagnostics

2021 ◽  
Author(s):  
Siheng Yang ◽  
Jianchen Wang ◽  
Zhichao Wang ◽  
Meng Han ◽  
Yuzhen Lin ◽  
...  
Keyword(s):  
Heat Release ◽  
Shear Layer ◽  
Optical Model ◽  
Flame Structure ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Main Stage ◽  
Staged Combustion ◽  
Swirl Number ◽  
Fuel Distribution

Abstract Lean premixed prevaporized combustors often feature staged combustion with a premixed main flame anchored by the nonpremixed pilot flame to obtain a wide operating range. Interaction between pilot flame and main flame is complex. The present article investigates the flame topologies and flame-fuel interactions in separated stratified swirl flames under various operating conditions (fuel to air ratio FAR and fuel stage ratio α) and injector designs (main stage swirl number Sm and fuel injection angle JA). Experiments are carried out in the centrally staged optical model combustor at inlet pressure P3 = 0.49–0.7 MPa and inlet temperature T3 = 539 K. At first, the flame structures obtained from OH-PLIF are investigated and discussed for the baseline injector (Sm = 0.9, JA = −50°). The V-shaped flame is stabilized in the inner shear layer (ISL) with the flame attachment point located at the lip for the pilot flame mode (α = 1). Dual flame is observed in the combustor for the fuel staged combustion (α < 1): the main flame stabilized in the outer shear layer (OSL) and the pilot flame stabilized in the inner shear layer (ISL). For increasing α from 0.15 to 0.25, gaps between the main flame and pilot flame are decreased, indicating a stronger interaction between the two flames. The flame structure for different injector geometries is then investigated. It is found that the higher main stage swirl number induces a larger flame opening angle, decreasing the interaction between two flames. Fuel injected into crossflow (JA = −50°) is found to generated a more separated flame, decreasing the flame interactions. Finally, fuel distribution measured by kerosene-PLIF is analyzed with the correlation to flame structure. Results show that the existence of a good mixing of fuel and fresh air in ISL and OSL provide favorable conditions for chemical reaction with high heat release. The OH distribution is highly correlated to fuel distribution. The fuel zone is located at the inner side of high OH region, indicating the reaction and heat release take place after the mixing of preheating of fuel-air mixture.

Control-Oriented Model of the Mean and Dispersion of Diesel Combustion Phasing With Ignition Assist

2021 ◽  
Author(s):  
Omar Ahmed ◽  
Robert Middleton ◽  
Anna Stefanopoulou ◽  
Kenneth Kim ◽  
Chol-Bum Kweon
Keyword(s):  
Diesel Engines ◽  
Controller Design ◽  
Thermal State ◽  
Operating Conditions ◽  
Injection Timing ◽  
Model Estimate ◽  
Combustion Behavior ◽  
Start Up ◽  
Crank Angle ◽  
Start Of Combustion

Abstract Diesel engines equipped with ignition assist devices such as glow plugs may improve combustion behavior at low temperatures and with low cetane fuels found in remote fields. The coordination of injection timing and the energy input of the ignition assist needs to continuously adjust to maintain the best combustion phasing at all conditions. However, most diesel engines do not use closed-loop combustion control and operate in a sub-optimal manner because the dispersion of combustion phasing, also known as cycle-to-cycle variability, requires careful feedback controller design. This work presents an initial investigation of a control-oriented model that captures the average and statistical influence of commercial glow plugs used for ignition assist beyond the start-up phase. Experiments were conducted at a single speed and load operating point as a proof of concept to obtain a model that quantifies the combustion phasing statistics and thus can guide feedback control design. The developed phenomenological model includes the engine’s thermal state because it impacts combustion behavior over the course of repeated experiments. The 3-term mean phasing model and 2-term standard deviation model estimate start of combustion within 0.6 and 0.2 crank angle degrees, respectively, and can be readily expanded to more operating conditions.

Modeling Ranges of Cyclic Variability for HCCI Ignition Timing Control

2011 ◽  
Author(s):  
Mahdi Shahbakhti ◽  
Ahmad Ghazimirsaied ◽  
Charles Robert Koch
Keyword(s):  
Probability Distribution ◽  
Intake Manifold ◽  
Average Error ◽  
Cyclic Variation ◽  
Ignition Timing ◽  
Shape Factors ◽  
Cyclic Variability ◽  
Distribution Shape ◽  
Crank Angle ◽  
Primary Reference

The probability distribution shape of the ignition timing ensemble allows detection of unstable operation near misfire in Homogeneous Charge Compression Ignition (HCCI) engines. The acceptable range of cyclic variation in HCCI combustion timing is determined by linking the experimental measurements with the shape factors of Generalized Extreme Value (GEV) probability distribution. A combined physical-statistical model is incorporated to analyze the range of cyclic variability in CA50 (crank angle of 50% mass fraction fuel burnt) for two single-cylinder engines. The model is validated with the experimental data at 227 operating points with five different Primary Reference Fuels (PRF). Good agreement between simulation and the experiment with an average error of 0.36 crank angle degree for predicting standard deviation of CA50 is obtained. Low, medium and high cyclic variability zones are identified as a function of intake manifold pressure, equivalence ratio, and intake manifold temperature. This information can be integrated into the design of an engine controller strategy to maintain acceptable levels of cyclic variation during a commanded engine load change.

Analysis of Incylinder Pressure and Temperature Variation in a Four-Stroke S. I. Engine Using Wiebe’s Combustion Model

2014 ◽  
Vol 984-985 ◽  
pp. 957-961
Author(s):  
Vijayashree ◽  
P. Tamil Porai ◽  
N.V. Mahalakshmi ◽  
V. Ganesan
Keyword(s):  
Heat Release ◽  
Combustion Process ◽  
Pressure Variation ◽  
Spark Ignition Engine ◽  
Working Fluid ◽  
Combustion Model ◽  
Cylinder Pressure ◽  
Crank Angle ◽  
Experimental Values ◽  
Release Model

This paper presents the modeling of in-cylinder pressure variation of a four-stroke single cylinder spark ignition engine. It uses instantaneous properties of working fluid, viz., gasoline to calculate heat release rates, needed to quantify combustion development. Cylinder pressure variation with respect to either volume or crank angle gives valuable information about the combustion process. The analysis of the pressure – volume or pressure-theta data of a engine cycle is a classical tool for engine studies. This paper aims at demonstrating the modeling of pressure variation as a function of crank angle as well as volume with the help of MATLAB program developed for this purpose. Towards this end, Woschni heat release model is used for the combustion process. The important parameter, viz., peak pressure for different compression ratios are used in the analysis. Predicted results are compared with experimental values obtained for a typical compression ratio of 8.3.

Combustion Improvement System in Boilers and Incinerators

2003 ◽  
Author(s):  
Wlodzimierz Blasiak ◽  
Weihong Yang
Keyword(s):  
Temperature Distribution ◽  
Heat Release ◽  
Combustion Chamber ◽  
Flue Gas ◽  
Operating Conditions ◽  
Waste Incinerator ◽  
The Novel ◽  
Biomass Waste ◽  
Injection Angle ◽  
Waste Incinerators

This work presents the main features, advantages and evaluation of applications of the novel “Ecotube” combustion improvement and emission reduction system by Ecomb AB of Sweden and Synterprise, LLC of Chattanooga, Tennessee. In the Ecotube system, the nozzles used for mixing are put on the suitable position inside the combustion chamber to control uniformity of temperature, mixing and reactants distribution in boilers and incinerators since the formation and reduction of pollutants (NO, CO and VOC) and in-furnace reduction processes (Air/Fuel staging, SNCR, flue gas recirculation and SOx reduction by dry sorbent injection) are related directly to mixing in a combustion chamber. The novel Ecotube combustion improvement system allows better control of mixing of the gases for example from a primary combustion zone with secondary combustion air or a recirculated flue gas. By means of the novel system it is possible to better control the residence time and to some degree gas phase temperature distribution as well as the heat release distribution in the furnace of the waste incinerators or boilers. This new combustion improvement system can be applied to supply different gas or liquid media — for example air, fuel, urea or even solid powder. Using the system a more efficient and environmentally clean combustion or incineration process can be performed. The Ecotube System may be used to meet increasingly stringent environmental emissions regulations, such as NOx SIP Call, while it delivers added benefits of reduced and stabilized CO and reduced fly ash and improved boiler efficiency. The study tool used in this work to present influence of the Ecotube system design on temperature as well as uniformity of reactants and flow field is numerical modeling. Using this tool, the influence of the position of the Ecotube system and the injection angle of the nozzles are studied. The studied boilers included the biomass waste incinerator, municipal solid waste incinerator and coal fired boiler. The concept of the Heat Release Distribution Ratio is proposed to classify the heat release inside the upper furnace of the boilers or incinerators. The results show that Ecotube spreads reaction zone over a larger furnace volume. The furnace flame occupation coefficient can be as high as 45% with the Ecotube system and it is around 40% higher comparing with the conventional multinozzle mixing system. Ecotube system allows keeping far more uniform heat release distribution, more uniform temperature distribution, and thus longer life of the heat transfer surfaces inside the furnace. Position of the Ecotube system and the injection angle of the nozzles are of primary importance and can be used as a technical parameter to control the boiler operation at different loads and varying operating conditions.

Numerical Investigation of Heat Transfer, Fluid Flow and Formation of Emissions in Diesel Engines

2013 ◽  
Author(s):  
Müjdat Firat
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Combustion Engine ◽  
Operating Conditions ◽  
Heat Transfer Fluid ◽  
Nox Emissions ◽  
Combustion Pressure ◽  
Crank Angle ◽  
The Relationship ◽  
Hole Number

The present study has been performed on heat transfer, fluid flow and formation of emissions in a diesel engine by different engine parameters. The analysis aims at an investigation of flow field, heat transfer, combustion pressure and formation of emission by means of numerical simulation which is using as parameter; hole number of injector and crank angle. Numerical simulations are performed using the AVL-FIRE commercial software depending on the crank angle. This software is successfully used in internal combustion engine applications, and its validity has been accepted. In this paper, k-zeta-f is preferred as turbulence model and SIMPLE/PISO used as algorithms. Thus, results are presented with pressure traces, temperature curves and NOx and soot levels for engine operating conditions. In addition, the relationship between the spray behaviors and combustion characteristics including NOx emissions, soot emissions, combustion pressure and temperature were illustrated through this analysis.

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