Modeling and simulation of frictional energy loss in mixed lubrication of a textured piston compression ring during warm-up of spark ignition engine

2016 ◽  
Vol 18 (4) ◽  
pp. 293-307 ◽  
Author(s):  
Ali Usman ◽  
Cheol Woo Park
Keyword(s):  
Energy Loss ◽  
Hydrodynamic Interaction ◽  
Surface Texturing ◽  
Cylinder Liner ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Warm Up ◽  
Frictional Behavior ◽  
Compression Ring ◽  
Recent Developments

Road vehicles account for a substantial portion of energy consumed by transportation. A large amount of this energy is lost to overcome friction within vehicle engines, in which the piston compression rings are a major source of such parasitic losses. The internal losses of engines increase several times in the case of unfavorable warm-up conditions. Recent developments in surface modification showed promising results in improving the frictional behavior of piston rings. Analyses are often idealized, such as isothermal conditions and unrealistic engine operating conditions. This study presents a numerical investigation of the frictional behavior of mixed-hydrodynamic interaction in a textured piston compression ring–cylinder liner during the warm-up process. The transient Reynolds equation is solved with a mass-conserving cavitation algorithm, realistic oil rheology, and practical engine operating conditions. Several multigrade and monograde oils are considered to draw comprehensive conclusions. The results show that ring surface texturing substantially reduces energy loss during the entire warm-up phase.

Surface and wear mechanisms analysis of phosphorous-free and conventional engine lubricants on cylinder liner and piston rings surfaces

2015 ◽  
Vol 67 (5) ◽  
pp. 441-448 ◽  
Author(s):  
Dogus Özkan ◽  
Hakan Kaleli ◽  
Yves BERTHIER ◽  
Levent Yüksek
Keyword(s):  
Wear Mechanisms ◽  
Cylinder Liner ◽  
Antiwear Additive ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Piston Rings ◽  
Additive Package ◽  
Content Type ◽  
Lubrication Oil ◽  
Endurance Tests

Purpose – This paper aims to investigate the wear mechanisms, formations and effectiveness of tribofilms of new developed, antiwear additive which is called mercapthocarboxylate. The mercapthocarboxylate is a sulphur-based and non-phosphorus additive. Design/methodology/approach – The effectiveness of the additive was examined through a set of laboratory endurance tests that applied with single cylinder spark ignition engine. Two types of lubricants were used to compare the engine tests which were thiophosphate (ZDDP) containing engine lubricant (phosphorus containing) and mercapthocarboxylate containing non-phosphorus and non-ash crankcase oil. Lubricants were tested under identical operating conditions for 100 hrs. The surfaces of cylinder liner and piston rings were inspected through optical microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy techniques. Findings – Catalysis-friendly and sulphur-based mercapthocarboxylate additive can be an alternative antiwear additive package for lubrication oil due to better wear performance when compared to ZDDP. Originality/value – Sulphur-based mercapthocarboxylate is a new developed antiwear additive and was applied to lubrication oil in this study. This lubrication oil was tested in the real engine environment by using 100-hr engine bench tests.

scholarly journals A Numerical Model to Study the Role of Surface Textures at Top Dead Center Reversal in the Piston Ring to Cylinder Liner Contact

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
N. Morris ◽  
R. Rahmani ◽  
H. Rahnejat ◽  
P. D. King ◽  
S. Howell-Smith
Keyword(s):  
Gas Flow ◽  
Fuel Efficiency ◽  
Surface Texturing ◽  
Engine Performance ◽  
Cylinder Liner ◽  
Operating Conditions ◽  
Ic Engine ◽  
Numerical Predictions ◽  
Combined Solution ◽  
Effect Of Surface

Minimization of parasitic losses in the internal combustion (IC) engine is essential for improved fuel efficiency and reduced emissions. Surface texturing has emerged as a method palliating these losses in instances where thin lubricant films lead to mixed or boundary regimes of lubrication. Such thin films are prevalent in contact of compression ring to cylinder liner at piston motion reversals because of momentary cessation of entraining motion. The paper provides combined solution of Reynolds equation, boundary interactions, and a gas flow model to predict the tribological conditions, particularly at piston reversals. This model is then validated against measurements using a floating liner for determination of in situ friction of an engine under motored condition. Very good agreement is obtained. The validated model is then used to ascertain the effect of surface texturing of the liner surface during reversals. Therefore, the paper is a combined study of numerical predictions and the effect of surface texturing. The predictions show that some marginal gains in engine performance can be expected with laser textured chevron features of shallow depth under certain operating conditions.

Theoretical Model for the Optimal Design of Surface Texturing on Piston Compression Ring

2015 ◽  
Vol 787 ◽  
pp. 327-331
Author(s):  
S. Prakash ◽  
G. Nagarajan
Keyword(s):  
Theoretical Model ◽  
Friction Force ◽  
Carrying Capacity ◽  
Piston Ring ◽  
Surface Texturing ◽  
Cylinder Liner ◽  
Load Carrying Capacity ◽  
Compression Ring ◽  
Load Carrying ◽  
Micro Dimples

A Theoretical model was developed to study the potential use of surface texturing for reducing the friction between a piston ring and cylinder liner. The model can predict the load-carrying capacity and friction force of the piston compression ring from Reynolds equation. The investigation is carried out using different dimple depths as well as different dimple diameters. Micro-dimples on the piston ring were able to generate significant hydrodynamic support. Numerical results show that surface texturing can decrease the friction force and extend the load-carrying capacity. The optimum surface texturing parameters such as dimples depth and dimples diameter were found.

Experimental Piston Ring Tribology for Marine Diesel Engines

2008 ◽  
Author(s):  
Peder Klit ◽  
Anders Vo̸lund
Keyword(s):  
Piston Ring ◽  
Real Life ◽  
Cylinder Liner ◽  
Operating Conditions ◽  
Test Apparatus ◽  
Important Condition ◽  
Frictional Behavior ◽  
Lubrication Regimes ◽  
Oil Distribution ◽  
Marine Diesel

A very important condition for describing the frictional behavior of a piston ring correctly is knowledge about the amount of lubricant present. It is often assumed that piston rings operate under fully flooded conditions, but this is not the case in real life operation. In large two-stroke engines the cylinder oil is supplied periodically to the bearing at discrete locations on the cylinder liner. The shifting in lubrication regimes and the non-uniform oil distribution opens for the possibility of starved conditions for the piston ring bearing. Therefore it is important to measure the oil distribution on the liner as a function of the operating conditions. The amount of lubricant available is reflected in the friction absorbed in the bearing. The paper describes an investigation of the tribological condition between a piston ring and cylinder. A test apparatus is used to study the interaction between a piston ring and a cylinder liner.

A Method to Determine Fuel Transport Dynamics Model Parameters in Port Fuel Injected Gasoline Engines During Cold Start and Warm-Up Conditions

2010 ◽  
Vol 132 (7) ◽  
Author(s):  
M. Shahbakhti ◽  
M. Ghafuri ◽  
A. R. Aslani ◽  
A. Sahraeian ◽  
S. A. Jazayeri ◽  
...  
Keyword(s):  
Thermal Conditions ◽  
Cold Start ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
New Method ◽  
Intake Manifold ◽  
Dynamics Model ◽  
Fuel Film ◽  
Warm Up ◽  
Transport Dynamics

In order to meet stringent emission standards, it is essential to have a precise control of air-fuel ratio (AFR) under cold start and warm-up conditions. This requires an understanding of the fuel transport dynamics in the intake system during these conditions. This study centers on estimating the parameters of a fuel transport dynamics model during engine operation at different thermal conditions ranging from cold start to fully warmed-up conditions. A method of system identification based on perturbing fuel injection rate is used to find fuel dynamics parameters in a port fuel injected (PFI) spark ignition engine. Since there was no cold chamber available to prepare cold start conditions, a new method was utilized to simulate cold start conditions. The new method can be applied on PFI engines, which use closed valve injection timing. A four-cylinder PFI engine is tested for different thermal conditions from −15°C to 82°C at a range of engine speeds and intake manifold pressures. A good agreement is observed between simulated and experimental AFR for 52 different transient operating conditions presented in this study. Results indicate that both fuel film deposit factor (X) and fuel film evaporation time constant (τf) decrease with increasing coolant temperature or engine speed. In addition, an increase in the intake manifold pressure results in an increase in X while causes a decrease in τf.

Two-Dimensional Temperature Distributions of Combustion Chamber Surfaces in a Firing Spark Ignition Engine

1994 ◽  
Vol 208 (2) ◽  
pp. 99-108 ◽  
Author(s):  
H Zhao ◽  
N Codings ◽  
T Ma
Keyword(s):  
Surface Temperature ◽  
Combustion Chamber ◽  
Thermal Imaging ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Two Dimensional ◽  
Warm Up ◽  
Temperature Distributions ◽  
Head Surface

This paper summarizes the development and application of advanced thermal imaging techniques to a spark ignition engine at the University of Cambridge Department of Engineering. A thermal imaging system is described which is capable of viewing and recording the cylinder head surface temperature and piston surface temperature in a firing spark ignition engine. Two-dimensional temperature distributions of these surfaces were measured both during the engine's warm-up period and steady state operations. The influence of the engine's operating conditions was examined upon the temperature distributions of combustion chamber surfaces during the engine's warm-up period. The effect of spark timings, particularly the onset of knocking combustion on the surface temperatures, has been studied.

Texturing Effects in Plane-Inclined Slider Bearings

2007 ◽  
Author(s):  
Mihai B. Dobrica ◽  
Michel Fillon ◽  
Mircea D. Pascovici ◽  
Traian Cicone
Keyword(s):  
Load Capacity ◽  
Surface Texturing ◽  
Cylinder Liner ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Hydrodynamic Performance ◽  
Slider Bearings ◽  
Parametric Studies ◽  
Friction Reducing ◽  
Performance Gains

Surface texturing has been shown to have friction reducing / load capacity increasing effects in parallel sliders, as well as in cylinder-liner contacts and in hydrodynamic seals. However, if texture is to be regarded as the sole mean of hydrodynamic lift in parallel sliders, or as a way of improving hydrodynamic performance in slider, thrust and journal bearings, several issues have to be addressed, such as optimal texturing parameters and corresponding performance gains. This paper deals with these issues in the case of a plane inclined textured slider. Parametric studies are conducted to determine optimal texturing extents, dimple depth and texturing density, as well as the influence of the operating conditions on these optimal texturing parameters.

Numerical optimization of surface texture for improved tribological performance of journal bearing at varying operating conditions

2018 ◽  
Vol 70 (9) ◽  
pp. 1608-1618 ◽  
Author(s):  
Ali Usman ◽  
Cheol Woo Park
Keyword(s):  
Journal Bearing ◽  
Hydrodynamic Lubrication ◽  
Surface Texturing ◽  
Tribological Performance ◽  
Operating Conditions ◽  
Content Type ◽  
Load Carrying ◽  
Recent Developments ◽  
Effect Of Surface ◽  
Generalized Reynolds Equation

Purpose Journal bearings are used in numerous rotary machines. The load carrying capacity and friction of a bearing have been major concerns in design. Recent developments in surface texturing have showed potential outcomes to improve the tribological characteristics of mating surfaces. This study aims to investigate surface textures, which are transverse to the sliding direction, for frictional response of the journal bearing. Design/methodology/approach A hydrodynamic lubrication model is considered to evaluate the effect of surface texturing on the performance of a journal bearing at varying operating conditions. The two-dimensional generalized Reynolds equation, coupled with mass-conserving Elrod cavitation algorithm, is solved to evaluate texture-induced variations in tribological performance parameters. Findings Results have showed remarkable improvements in frictional response. Moreover, micro-textures on the journal surface alter the cavitation response and film-reformation in the hydrodynamic conjunction of the plain bearing. Originality/value Operating condition-based comprehensive exhaustive optimization of texture geometry is performed to generate widespread conclusion.

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