Finite Element Modeling of Piston-Ring Dynamics and Blowby Estimation in Single-Cylinder IC Engine

Author(s):  
S. N. Kurbet ◽  
R. Krishna Kumar

The ring geometry, its assembly load and its mechanical and thermal properties are factors that influence engine performance. The ring dynamics is greatly influenced by piston secondary motions that depend upon the piston geometry, piston pin offset, its center of gravity (C.G.) location and piston-liner clearance. The engine is simulated to study the rings motion in axial, radial direction and the gap areas are calculated to estimate blowby and compared with experimental results. This approach to engine design reduces the conceptual design-to-development cycle time and reduces the need of extensive engine testing for evaluating ring performance.

The Internal Combustion(IC) engine design and growth plays an important role in determining engine performance and emission features. The performance and emission properties of the spark ignition (SI) motor are also more influenced by gasoline ethanol blends. In this work, an effort has been made to optimize the operating parameters in order to minimize BSFC, CO, NO2 , CO2 , HC and maximize BTE using Response Surface Methodology (RSM). The engine is operated under constant speed conditions with different working conditions for better mixing and distinct additive composition (iso-octane) in the range of 0.3%, 0.4% and 0.5%. The appropriate RSM was used to reduce the use of petrol, its exhausts and maximize Brake Thermal Efficiency. The experimental and statistical approximation demonstrates the rise in Thermal Brake Efficiency (BTE) and decline in Specific Brake Fuel Consumption (BSFC). In addition, the chosen RSM model demonstrates reduced CO, HC, NO2 and CO2 emissions. From the assessment, it is noted that E30 mix with 0.5% additive has better motor efficiency features and reduced emissions at a peak speed of 1800rpm among all test blends with varying proportion of additives.


Author(s):  
Yirop Kim ◽  
Myoungsoo Kim ◽  
Han Ho Song

For past decades, substantial developments have been accomplished in internal combustion (IC) engine technology, but there still remain some possible improvements. The combustion in an IC engine is a highly intricate phenomenon, thus, numerous factors correlated with different forms of loss decides the efficiency of an engine. In spark-ignition (SI) engines, the combustion duration is considered important because it plays a key role in determining the combustion phasing for best possible energy conversion. The geometry of engine components may directly change the burning rate of air-fuel mixture, therefore, it should also be considered as significant as other aspects like exhaust gas recirculation (EGR) rate or boosting in investigation of the engine performance. This is the reason the development engineers are putting their effort to design an engine with optimized flow motion. Tweaking the flow dynamics via design modification or use of auxiliary device influences the turbulence level inside the combustion chamber, thus, the burning rate as well. Intake port orientation, masking, and piston shape are one of the typical design parameters manipulated for such purpose, and profound understanding on the effect of these design parameters on burning rate is encouraged in order to assist the optimization process. The design optimization process should be based on a fundamental understanding of how the design parameters affect the flow motion and combustion characteristics. This study aims for a simpler and faster method to investigate the consequences of design modifications. As a base model, a physics-based quasi-dimensional (QD) engine model is developed for simulation of SI combustion phenomenon. It is modeled to consider the change in flow motion and turbulence properties via simplified modeling. The advantages of such QD model is that it requires much less computational resource compared to 3D CFD model, and allows a greater degree of freedom within the simulation process which facilitates parametric studies. A zero-dimensional (0D) turbulence submodel is used to describe energy cascade mechanism, and turbulence intensity is calculated reflecting the effect cause by design modification. According to the sensitivities drawn from parametric study, the results of each effect on burning rate and other engine performance properties are compared individually and collectively. A qualitative analysis suggests how sensitive each effect are at given operating conditions. The result infers that the flow concentration by port design modification boosts the burning rate, but it is advantageous in terms of fuel economy to enhance the breathing ability by valve masking. The product of this comparative study assists an intuitive understanding on how the design modification would affect the engine operations, and it is encouraged to develop the model further via validation with experiment data to provide more reliable output. It is believed that it can be utilized as a good reference in engine design process.


2019 ◽  
pp. 089270571987822
Author(s):  
Saud Aldajah ◽  
Mohammad Y Al-Haik ◽  
Waseem Siddique ◽  
Mohammad M Kabir ◽  
Yousef Haik

This study reveals the enhancement of mechanical and thermal properties of maleic anhydride-grafted polypropylene (PP- g-MA) with the addition of nanocrystalline cellulose (NCC). A nanocomposite was manufactured by blending various percentages of PP, MA, and NCC nanoparticles by means of a twin-screw extruder. The influence of varying the percentages of NCC on the mechanical and thermal behavior of the nanocomposite was studied by performing three-point bending, nanoindentation, differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier-transform infrared (FTIR) spectroscopy tests. The novelty of this study stems on the NCC nanoparticles and their ability to enhance the mechanical and thermal properties of PP. Three-point bending and nanoindentation tests revealed improvement in the mechanical properties in terms of strength, modulus, and hardness of the PP- g-MA nanocomposites as the addition of NCC increased. SEM showed homogeneity between the mixtures which proved the presence of interfacial adhesion between the PP- g-MA incorporated with NCC nanoparticles that was confirmed by the FTIR results. DSC and TGA measurements showed that the thermal stability of the nanocomposites was not compromised due to the addition of the coupling agent and reinforced nanoparticles.


2019 ◽  
Vol 45 (12) ◽  
pp. 15596-15602 ◽  
Author(s):  
Xinlei Gu ◽  
Lina Yang ◽  
Xiaorong Ma ◽  
Xuan Dai ◽  
Jia Wang ◽  
...  

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