An Analysis of Ring Temperature, Oil Film Temperature and Oil Film Thickness on a Piston Ring of an IC Engine in Consideration of Ring Movement: Effect of Ring Sliding Face Profile

2007 ◽  
Author(s):  
Takashi Ishijima ◽  
Akiko Shimada ◽  
Shinichiro Kodaira ◽  
Hiroshi Sakamoto ◽  
Yasuo Harigaya ◽  
...  
Keyword(s):  
Film Thickness ◽  
Internal Combustion Engines ◽  
Piston Ring ◽  
Characteristic Temperature ◽  
Combustion Engines ◽  
Ring Groove ◽  
Ic Engine ◽  
Lower Face ◽  
Oil Film ◽  
Movement Effect

For the clarification of the lubrication and thermal problems between ring and liner of internal combustion engines, an unsteady thermohydrodynamic lubrication model considering the ring temperature and the ring movement in the piston ring groove was developed. Then using the method of thermohydrodynamic lubrication, the effect of the profile of top ring sliding face on the oil film thickness and friction losses was analyzed. The ring is width of 3mm and thickness of 4.5mm. Profiles in sliding face of the ring used are two types. Ring 1 has a flat in the middle and a roundness in the corner, and Ring 2 has a barrel face. The ring temperature on the sliding surface shows the characteristic temperature distribution, and the temperature difference between ring lower face and middle of ring has about 19 °C. The oil film thickness changed in a cycle increases with increase of barrel height. The friction mean effective pressure FMEP decreases with the increase of barrel height both Ring 1 and Ring 2. FMEP of Ring 2 is more effective than that of Ring 1.

An analytical study of tribological parameters between piston ring and cylinder liner in internal combustion engines

2016 ◽  
Vol 230 (4) ◽  
pp. 329-349 ◽  
Author(s):  
Mohamed Kamal Ahmed Ali ◽  
Hou Xianjun ◽  
Richard Fiifi Turkson ◽  
Muhammad Ezzat
Keyword(s):  
Film Thickness ◽  
Internal Combustion Engines ◽  
Piston Ring ◽  
Cylinder Liner ◽  
Combustion Engines ◽  
Oil Viscosity ◽  
Oil Film ◽  
Ring Assembly ◽  
Ring Dynamics ◽  
Tribological Parameters

This paper presents a model to study the effect of piston ring dynamics on basic tribological parameters that affect the performance of internal combustion engines by using dynamics analysis software (AVL Excite Designer). The paramount tribological parameters include friction force, frictional power losses, and oil film thickness of piston ring assembly. The piston and rings assembly is one of the highest mechanically loaded components in engines. Relevant literature reports that the piston ring assembly accounts for 40% to 50% of the frictional losses, making it imperative for the piston ring dynamics to be understood thoroughly. This analytical study of the piston ring dynamics describes the significant correlation between the tribological parameters of piston and rings assembly and the performance of engines. The model was able to predict the effects of engine speed and oil viscosity on asperity and hydrodynamic friction forces, power losses, oil film thickness and lube oil consumption. This model of mixed film lubrication of piston rings is based on the hydrodynamic action described by Reynolds equation and dry contact action as described by the Greenwood–Tripp rough surface asperity contact model. The results in the current analysis demonstrated that engine speed and oil viscosity had a remarkable effect on oil film thickness and hydrodynamic friction between the rings and cylinder liner. Hence, the mixed lubrication model, which unifies the lubricant flow under different ring–liner gaps, is needed via the balance between the hydrodynamic and boundary lubrication modes to obtain minimum friction between rings and liner and to ultimately help in improving the performance of engines.

Modeling the Lubrication, Dynamics, and Effects of Piston Dynamic Tilt of Twin-Land Oil Control Rings in Internal Combustion Engines

1999 ◽  
Vol 122 (1) ◽  
pp. 119-129 ◽  
Author(s):  
T. Tian ◽  
V. W. Wong
Keyword(s):  
Film Thickness ◽  
Internal Combustion Engines ◽  
Three Dimensional ◽  
Internal Combustion ◽  
Asperity Contact ◽  
Combustion Engines ◽  
Ring Groove ◽  
Oil Film ◽  
Oil Transport ◽  
Axial Forces

A theoretical model was developed to study the lubrication, friction, dynamics, and oil transport of twin-land oil control rings (TLOCR) in internal combustion engines. A mixed lubrication model with consideration of shear-thinning effects of multigrade oils was used to describe the lubrication between the running surfaces of the two lands and the liner. Oil squeezing and asperity contact were both considered for the interaction between the flanks of the TLOCR and the ring groove. Then, the moments and axial forces from TLOCR/liner lubrication and TLOCR/groove interaction were coupled into the dynamic equations of the TLOCR. Furthermore, effects of piston dynamic tilt were considered in a quasi three-dimensional manner so that the behaviors of the TLOCR at different circumferential locations could be studied. As a first step, variation of the third land pressure was neglected. The model predictions were illustrated via an SI engine. One important finding is that around thrust and anti-thrust sides, the difference between the minimum oil film thickness of two lands can be as high as several micrometers due to piston dynamic tilt. As a result, at thrust and anti-thrust sides, significant oil can pass under one land of the TLOCR along the bore, although the other land perfectly seals the bore. Then, the capabilities of the model were further explained by studying the effects of ring tension and torsional resistance on the lubrication and oil transport between the lands and the liner. The effects of oil film thickness on the flanks of the ring groove on the dynamics of the TLOCR were also studied. Friction results show that boundary lubrication contributes significantly to the total friction of the TLOCR. [S0742-4795(00)01801-9]

An Analysis of Ring Temperature, Oil Film Temperature, Oil Film Thickness and Heat Transfer on a Piston Ring of an IC Engine in Consideration of Ring Movement in a Cycle

2006 ◽  
Author(s):  
Takashi Ishijima ◽  
Akiko Shimada ◽  
Yasuo Harigaya ◽  
Michiyoshi Suzuki ◽  
Masaaki Takiguchi
Keyword(s):  
Heat Transfer ◽  
Heat Flow ◽  
Film Thickness ◽  
Piston Ring ◽  
Heat Flow Rate ◽  
Two Dimensional ◽  
Ring Groove ◽  
Ic Engine ◽  
Oil Film ◽  
Face Temperature

An unsteady and two-dimensional thermohydrodynamic lubrication model in consideration of the ring movement and the heat flow from ring groove to piston ring was developed. The piston ring temperature in an internal combustion engine was analyzed by using the unsteady and two-dimensional form heat-conduction equation in consideration of axial movement of ring and heat flow from ring groove to ring during a cycle. The oil film temperature, oil film thickness and heat transfer between ring and liner surfaces were analyzed by using the calculated ring temperature taking into consideration cycle variation. The results are as follows. The heat flow rate around ring changes greatly with the ring movement and the ring sliding face temperature changes about 6 °C in a cycle. Then, the cycle mean temperature of ring sliding face becomes lower than the ring sliding face temperature calculated by the ring groove and liner surface temperatures under 2800 rpm and full load conditions. Therefore, the oil film viscosity is higher than that of the conventional viscosity model in which the viscosity was based on a constant ring sliding face temperature in a cycle. The oil film thickness predicted by the present method is thicker than that calculated by our previous method.

Experimental Investigation of Oil Accumulation in Second Land of Internal Combustion Engines

2005 ◽  
Vol 127 (1) ◽  
pp. 206-212
Author(s):  
T. Icoz ◽  
Z. Dursunkaya
Keyword(s):  
Film Thickness ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Engine Oil ◽  
Combustion Engines ◽  
Oil Consumption ◽  
Oil Accumulation ◽  
Oil Film ◽  
Piston Cylinder ◽  
Total Oil

Blowback of engine oil suspended in combustion gases, when the gas flows from the piston second land back into the combustion chamber, is believed to contribute to oil consumption and hydrocarbon emissions in internal combustion engines. Oil accumulation in the region between top and second compression rings is a factor that influences this phenomenon. The effects of individual parameters, such as oil film thickness and viscosity, however, have still not been understood. The present study was aimed at constructing an experimental setup to study the effect of oil film thickness on oil accumulation in the second land of internal combustion engines. Due to the inherent difficulties of experimentation on production engines, a modeled piston-cylinder assembly was constructed. Total oil accumulation in the modeled second land after a single piston stroke was measured and compared to oil consumption in operating engines.

Characterization of the Ring Pack Lubricant and its Environment

1995 ◽  
Vol 209 (2) ◽  
pp. 109-118 ◽  
Author(s):  
P J Burnett ◽  
B Bull ◽  
R J Wetton
Keyword(s):  
Internal Combustion Engines ◽  
Piston Ring ◽  
Combustion Engines ◽  
Oil Consumption ◽  
Ring Groove ◽  
Direct Sampling ◽  
Engine Wear ◽  
Ring Pack ◽  
Motion Characterization

The performance characteristics of the piston ring-liner assembly and the lubricant within it are critical for the operation of modern internal combustion engines. The ring pack can directly affect engine friction, oil consumption and oil degradation, which in turn can impact upon fuel economy, emissions and engine wear. The operation of this system is complex and no single technique is capable of fully characterizing the processes occurring. This paper outlines the range of both experimental and theoretical methods that are being applied to the study of this system and the lubricant within it. These include the modelling of ring pack gas and oil flows, and direct measurement of piston temperatures, ring belt pressures and piston ring motion. Characterization of lubricant degradation via direct sampling of oil from the top ring groove of an operating engine has also been used. The merits of such a multi-faceted approach are discussed in relation to piston deposit formation.

Piston Rings Friction Comparison in a Free Piston and Conventional Crankshaft Engines

2018 ◽  
Author(s):  
Mehar Bade ◽  
Nigel N. Clark ◽  
Terence Musho ◽  
Parviz Famouri
Keyword(s):  
Film Thickness ◽  
Internal Combustion Engines ◽  
Asperity Contact ◽  
Combustion Engines ◽  
Power Losses ◽  
Piston Rings ◽  
Free Piston ◽  
Oil Film ◽  
Frictional Losses ◽  
Free Piston Engine

The conventional internal combustion engines driven by crankshafts and connecting rod mechanisms are restrained by combustion, thermal and mechanical inefficiencies. The Oscillating Free Piston Linear Engine Alternator (OFPLEA) produces electric power with no need to modify the reciprocating motion to rotary motion. In the most common geometry it consists of a linear alternator driven cyclically by one or two internal combustion engines. With the elimination of crankshaft mechanism linkages, the free piston engine offers potential benefits over crankshaft engines in terms of total mechanical losses. A significant proportion of 5% to 12% of total fuel energy in conventional engines is consumed to overcome the frictional losses. This research investigation addresses an analytical and numerical model to simulate the tribological performance of piston rings in an OFPLEA engine. The results are then compared with results from an equivalent conventional crankshaft driven engine. This axisymmetric, mixed lubrication tribological model is developed on the hydrodynamic process defined by Patir and Cheng’s modified Reynolds equation and an asperity contact process as defined by Greenwood and Tripp’s rough surface dry contact model. The asperity contact pressure distribution, hydrodynamic pressure distribution, lubricant oil film thickness, frictional force and frictional power losses are calculated using an explicit finite difference approach. In the absence of spring-dominated OFPLEA system, dissimilarity in the piston motion profile for compression and power stroke exhibited two different oil film thickness peaks. Whereas a similar oil film thickness peaks are observed for conventional engine due to the controlled and stable operation maintained by crankshaft mechanism. The simulation results state that the frictional losses due to piston ring - cylinder liner contact are found to be lower for a free piston engine than for those of a corresponding crankshaft engine. The simulated piston ring frictional power losses are found to be 342.8 W for the OFPLEA system and 382.6 W for the crankshaft engine. Further, an overall system efficiency improvement of 0.6 % is observed for an OFPLEA engine due to these reduced frictional losses from piston rings.

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