Air Charge and Residual Gas Fraction Estimation for a Spark-Ignition Engine Using In-Cylinder Pressure

2017 ◽  
Author(s):  
Arya Yazdani ◽  
Jeffrey Naber ◽  
Mahdi Shahbakhti ◽  
Paul Dice ◽  
Chris Glugla ◽  
...  
Keyword(s):  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Cylinder Pressure ◽  
Residual Gas Fraction ◽  
Residual Gas

scholarly journals Comparative Study of the Effective Release Energy, Residual Gas Fraction, and Emission Characteristics with Various Valve Port Diameter-Bore Ratios (VPD/B) of a Four-Stroke Spark Ignition Engine

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1330 ◽  
Author(s):  
Nguyen Xuan Khoa ◽  
Ocktaeck Lim
Keyword(s):  
Load Condition ◽  
Experimental System ◽  
Optimization Method ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Pressure Increase ◽  
Intake Port ◽  
Exhaust Port ◽  
Residual Gas Fraction ◽  
Residual Gas

In this research, the residual gas, peak firing pressure increase, and effective release energy were completely investigated. To obtain this target, the experimental system is installed with a dynamo system and a simulation model was setup. Through combined experimental and simulation methods, the drawbacks of the hardware optimization method were eliminated. The results of the research show that the valve port diameter-bore ratio (VPD/B) has a significant effect on the residual gas, peak firing pressure increase, and effective release energy of a four-stroke spark ignition engine. In this research, the engine was performed at 3000 rpm and full load condition. Following increased IPD/B ratio of 0.3–0.5. The intake port and exhaust port diameter has a contrary effect on engine volumetric efficiency, the residual gas ratio increase 27.3% with larger intake port and decrease 18.6% with larger exhaust port. The engine will perform optimal thermal efficiency when the trapped residual gas fraction ratio is from 13% to 14%. The maximum effective release energy was 0.45 kJ at 0.4 intake port-bore ratio, and 0.451 kJ at 0.35 exhaust port-bore ratio. The NOx emission increases until achieved a maximum value after that decrease even VPD/B was still increasing. With a VPD/B ratio of 0.35 to 0.4, the engine works without the misfiring.

An Evaluation of Residual Gas Fraction Measurement Techniques in a High Degree of Freedom Spark Ignition Engine

2008 ◽  
Vol 1 (1) ◽  
pp. 71-84 ◽  
Author(s):  
Robert G. Prucka ◽  
Zoran Filipi ◽  
Dennis N. Assanis ◽  
Denise M. Kramer ◽  
Gregory L. Ohl
Keyword(s):  
Measurement Techniques ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Degree Of Freedom ◽  
Residual Gas Fraction ◽  
Residual Gas ◽  
Fraction Measurement ◽  
High Degree

Investigating the Effects of Engine Operating Conditions on the Cyclic Variability of a Commercial Flex-Fuel Engine

2019 ◽  
Author(s):  
Fazal Um Min Allah ◽  
Caio Henrique Rufino ◽  
Waldyr Luiz Ribeiro Gallo ◽  
Clayton Barcelos Zabeu
Keyword(s):  
Spark Ignition ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Cylinder Pressure ◽  
Cyclic Variability ◽  
Indicated Mean Effective Pressure ◽  
Mass Fractions ◽  
Cyclic Variations ◽  
Flex Fuel ◽  
Hydrous Ethanol

Abstract The flex-fuel engines are quite capable of running on gasohol and hydrous ethanol. However, the in-cylinder cyclic variations, which are inherently present in spark-ignition (SI) engines, affect the performance of these engines. Therefore, a comprehensive analysis is required to evaluate the effects of in-cylinder cyclic variations of a flex-fuel engine. The experiments were carried out by using Brazilian commercial Gasohol E27 (mixture of 27% anhydrous ethanol in gasoline) and hydrous ethanol E95h (5% water by volume in ethanol) as fuels for a commercial flex-fuel spark ignition engine. A comparison between the cyclic variations of gasohol and hydrous ethanol is presented in this paper. Moreover, the effects of engine operating parameters (i.e., engine speed, engine load and relative air fuel ratio) on cyclic variations are also investigated. The acquired data of in-cylinder pressure and combustion durations are evaluated by carrying out a statistical analysis. The coefficient of variation for indicated mean effective pressure (IMEP) did not exceed the limit of 5% for all tested conditions. Higher cyclic variability of maximum in-cylinder pressure is observed for gasohol fuel and higher engine speeds. The variability of in-cylinder combustion is also evaluated with the help of different combustion stages, which are characterized by corresponding crank positions of 10%, 50% and 90% mass fractions burned.

Validation of Species-Based Extended Coherent Flamelet Model in a Large Eddy Simulation of a Homogeneous Charge Spark Ignition Engine

2020 ◽  
Author(s):  
Y. See ◽  
M. Wang ◽  
J. Bohbot ◽  
O. Colin
Keyword(s):  
Large Eddy Simulation ◽  
Computational Cost ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Cylinder Pressure ◽  
Flamelet Model ◽  
Progress Variable ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Homogeneous Charge

Abstract The Species-Based Extended Coherent Flamelet Model (SB-ECFM) was developed and previously validated for 3D Reynolds-Averaged Navier-Stokes (RANS) modeling of a spark-ignited gasoline direct injection engine. In this work, we seek to extend the SB-ECFM model to the large eddy simulation (LES) framework and validate the model in a homogeneous charge spark-ignited engine. In the SB-ECFM, which is a recently developed improvement of the ECFM, the progress variable is defined as a function of real species instead of tracer species. This adjustment alleviates discrepancies that may arise when the numerical treatment of real species is different than that of the tracer species. Furthermore, the species-based formulation also allows for the use of second-order numeric, which can be necessary in LES cases. The transparent combustion chamber (TCC) engine is the configuration used here for validating the SB-ECFM. It has been extensively characterized with detailed experimental measurements and the data are widely available for model benchmarking. Moreover, several of the boundary conditions leading to the engine are also measured experimentally. These measurements are used in the corresponding computational setup of LES calculations with SB-ECFM. Since the engine is spark ignited, the Imposed Stretch Spark Ignition Model (ISSIM) is utilized to model this physical process. The mesh for the current study is based on a configuration that has been validated in a previous LES study of the corresponding motored setup of the TCC engine. However, this mesh was constructed without considering the additional cells needed to sufficiently resolve the flame for the fired case. Thus, it is enhanced with value-based Adaptive Mesh Refinement (AMR) on the progress variable to better capture the flame front in the fired case. As one facet of model validation, the ensemble average of the measured cylinder pressure is compared against the LES/SB-ECFM prediction. Secondly, the predicted cycle-to-cycle variation by LES is compared with the variation measured in the experimental setup. To this end, the LES computation is required to span a sufficient number of engine cycles to provide statistical convergence to evaluate the coefficient of variation (COV) in peak cylinder pressure. Due to the higher computational cost of LES, the runtime required to compute a sufficient number of engine cycles sequentially can be intractable. The concurrent perturbation method (CPM) is deployed in this study to obtain the required number of cycles in a reasonable time frame. Lastly, previous numerical and experimental analyses of the TCC engine have shown that the flow dynamics at the time of ignition is correlated with the cycle-to-cycle variability. Hence, similar analysis is performed on the current simulation results to determine if this correlation effect is well-captured by the current modeling approach.

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