scholarly journals Experimental Study of Lube Oil Characteristics in the PCV System and Effects on Engine Oil Consumption

2004 ◽  
Author(s):  
Oscar Lopez ◽  
Tian Tian ◽  
Victor W. Wong
Keyword(s):  
Strong Relationship ◽  
Spark Ignition Engine ◽  
Engine Oil ◽  
Outlet Temperature ◽  
Oil Consumption ◽  
Crankcase Ventilation ◽  
Air Intake ◽  
Oil Characteristics ◽  
Ring Pack ◽  
The Impact

Engine oil consumption is an important source of hydrocarbon and particulate emissions in modern automobile engines. Great efforts are being made in recent years to minimize the impact of oil consumption on engine emissions. Research engineers continue to study the sources and driving mechanisms of oil consumption. Of these mechanisms, the contribution from the Positive Crankcase Ventilation (PCV) system is the least investigated. However, recent studies have shown that the blowby contribution to oil consumption could be significant under certain conditions. The PCV system refers to the system that vents the blowby gases loaded with oil back to the engine air intake system. It includes oil separators, air breather connecting the intake with the crankcase, and a flow-regulating valve. In a closed crankcase ventilation system, the oil-loaded blowby and crankcase gases are fed back into the air intake. Blowby gases are formed during engine operation by leakage of unburdened and compressed air-fuel mixture from the combustion chamber past the engine piston and ring pack into the crankcase. The oil that is circulated back into the intake through the PCV system could leave deposits in the intake manifold, and thus both the quantity and physical characteristics of the re-circulated oil are of great interest. This study analyzes the PCV blowby-oil consumption mechanisms and examines the main oil sources and oil characteristics by combining oil-consumption with in-cylinder measurements. A sulfur-tracer method was used along with a gravimetric method to measure the blowby oil consumption dependence on oil level, coolant outlet temperature, operating speed and load in a production spark ignition engine. Liquid oil distribution on the liner and piston was also studied using a Laser Induced Fluorescence (LIF) technique. In addition, in-cylinder variables such as the liner temperature and cylinder pressure that affect the oil evaporation and blowby flow rates were also measured. The blowby oil consumption map showed an increase in oil consumption with load and speed. Further analysis showed that the blowby flow was mainly dependent on the load of the engine, whereas the oil concentration in the blowby did not show this strong relationship. Whether the blowby gases pick up more oil in the ring-pack region than oil in the crankcase was thus carefully analyzed. Supplementally, a strong relationship was observed between oil consumption and sump oil level, showing that oil in the crankcase is an important source of oil in the blowby. More experiments were run at different coolant outlet temperatures to study the blowby oil consumption aimed at identifying the sources of oil in the blowby. The results show that oil evaporation is dependent on the liner temperatures that increase with load and speed. These data provided additional information to distinguish among the possible sources of blowby oil consumption. Additional experimentation was carried out to estimate drop-size distribution of oil suspended in the ventilated gases, which showed that entrainment of small oil droplets in the PCV flow varied with both speed and load.

Numerical Investigation of the Effects of Axial Cylinder Bore Profiles on Piston Ring Radial Dynamics

2003 ◽  
Vol 125 (4) ◽  
pp. 1081-1089 ◽  
Author(s):  
Y. Piao ◽  
S. D. Gulwadi
Keyword(s):  
High Speed ◽  
Piston Ring ◽  
Gasoline Engine ◽  
Engine Performance ◽  
Operating Conditions ◽  
Engine Oil ◽  
Oil Consumption ◽  
Ring Pack ◽  
Cylinder Bore

The role of cylinder bore shapes in engine performance has been the subject of several studies in recent years. In particular, the influence of bore distortion on oil consumption under high speed conditions has generated significant interest. In this paper, the effect of an axial bore profile on radial dynamics of a ring is investigated. Radial ring motions within grooves due to the axial bore profile can generate significant inertial effects and also have an impact on ring end-gap sizes and lubrication conditions at the ring-liner interfaces. The magnitude of such effects is dependent on the ring-pack configuration, engine operating conditions (speed and load) and axial bore profile details. These issues are investigated in this study due to their implication on engine oil consumption, friction and blow-by. The authors have developed an analytical expression to account for the effects of radial ring inertia due to an axial bore profile for implementation in a piston ring-pack simulation tool RINGPAK. Simulation results from a gasoline engine study are presented to illustrate the effects of engine speeds, ring tensions, and characteristics of axial bore profiles on ring radial dynamics and ring-liner lubrication. Relevant qualitative comparisons are made to experimental measurements available in the literature.

Blow-By Truck Application: Electrically Driven Cone Stack Separator for Crankcase Ventilation

2007 ◽  
Author(s):  
Gerd Kissner ◽  
Hartmut Sauter
Keyword(s):  
Separation Efficiency ◽  
Ventilation System ◽  
Motor Vehicles ◽  
Cylinder Wall ◽  
Oil Consumption ◽  
Control Laws ◽  
Crankcase Ventilation ◽  
Oil Fraction ◽  
Air Intake ◽  
Oil Mist

Dealing with the blow-by gas from reciprocating engine is a bigger challenge nowadays due to strict emission control laws and design limitations. Blow-by gas originates between the piston or piston rings and the cylinder wall and is charged with oil when it leaves the crankcase. In a closed crankcase ventilation system these blow-by gases are drawn from the crankcase into the air intake. The oil mist separator (OMS) retains a fraction of the liquid oil and returns the retained oil fraction back to the oil sump. Thus, the oil mist separator reduces oil consumption and emissions. Electrically driven cone stack separators have high separation efficiency, small differential pressure, arbitrary mounting position and low power consumption. In addition to that, the electrically driven cone stack separator has also advantageous control characteristics. Since commercial motor vehicles already have high electrical system requirements a Mechatroic concept is presented here which was developed to be maintenance-free over the lifetime of the engine. This is achieved by detailed design and choice of special materials. In this paper, the construction and application of the novel oil mist separator system for trucks are discussed in detail.

Numerical Investigation of the Effects of Axial Cylinder Bore Profiles on Piston Ring Radial Dynamics

2002 ◽  
Author(s):  
Y. Piao ◽  
S. D. Gulwadi
Keyword(s):  
High Speed ◽  
Piston Ring ◽  
Gasoline Engine ◽  
Engine Performance ◽  
Operating Conditions ◽  
Engine Oil ◽  
Oil Consumption ◽  
Ring Pack ◽  
Cylinder Bore

The role of cylinder bore shapes in engine performance has been the subject of several studies in recent years. In particular, the influence of bore distortion on oil consumption under high speed conditions has generated significant interest. In this paper, the effect of an axial bore profile on radial dynamics of a ring is investigated. Radial ring motions within grooves due to the axial bore profile can generate significant inertial effects and also have an impact on ring end-gap sizes and lubrication conditions at the ring-liner interfaces. The magnitude of such effects is dependent on the ring-pack configuration, engine operating conditions (speed and load) and axial bore profile details. These issues are investigated in this study due to their implication on engine oil consumption, friction and blow-by. The authors have developed an analytical expression to account for the effects of radial ring inertia due to an axial bore profile for implementation in a piston ring–pack simulation tool RINGPAK. Simulation results from a gasoline engine study are presented to illustrate the effects of engine speeds, ring tensions and characteristics of axial bore profiles on ring radial dynamics and ring-liner lubrication. Relevant qualitative comparisons are made to experimental measurements available in the literature.

Computer Program Development Predicting Engine Oil Consumption

2005 ◽  
Author(s):  
Sang Myung Chun
Keyword(s):  
Computer Program ◽  
Gas Flow ◽  
Piston Ring ◽  
Engine Performance ◽  
Engine Oil ◽  
Optimized Design ◽  
Oil Consumption ◽  
Piston Cylinder ◽  
Piston Ring Pack ◽  
Ring Pack

The oil consumption and blow-by gas through piston-cylinder-ring crevices have to be minimized. Meanwhile, the friction losses in the piston ring pack need to be reduced in order to improve fuel economy and engine performance. In these two aspects, study on the optimized design of the piston ring pack has to be carried out. The amounts of oil consumption and blow-by gas are important factors to decide whether an engine is operating under good conditions or not during engine development and engine life cycle. The purpose of this study is to develop a computer program predicting engine oil consumption and blow-by gas by calculating the amount of oil flowing into the combustion chamber and gas flow down to the crankcase through the piston ring pack. Using this program, the condition of an engine can be predicted in advance.

Three Dimensional Ring Dynamics Modeling Approach for Analyzing Lubrication, Friction and Wear of Piston Ring-Pack

2017 ◽  
Author(s):  
K. G. Mahmoud ◽  
O. Knaus ◽  
T. Parikyan ◽  
M. Patete
Keyword(s):  
Friction And Wear ◽  
Piston Ring ◽  
Parameter Analysis ◽  
Engine Oil ◽  
Oil Consumption ◽  
Modeling Approach ◽  
Power Cylinder ◽  
Piston Ring Pack ◽  
Ring Pack ◽  
Cylinder Bore

The automotive industry is subjected to increasing pressure in order to improve fuel efficiency and reduce the CO2 emissions of internal combustion (IC) engines. The power cylinder system (piston, piston ring, and liner) contributes significantly to the friction losses, engine oil consumption and gas leakage called blow-by. The role of cylinder bore shape in engine performance has been the subject of several studies in recent years. High bore distortion must be avoided because it can lead to ring conformability issues, which leads to inadequate sealing resulting in increased blow-by and oil consumption. It also leads to asperity contact between the piston skirt and cylinder bore increasing friction causing abnormally high surface wear. Although bore distortion cannot be eliminated, engine manufacturers strive to contain it within acceptable limits. Therefore, numerical analysis of the power cylinder with physically based mathematical models becomes very essential to the engine and component manufacturer in order to reduce engine development lead time and minimize the number of engine tests. The integrated ring-pack modeling methodology developed by the authors [1] is used to investigate the piston ring-pack performance. Although the modeling approach can be used for extensive parameter analysis of piston, piston rings and lubrication oil consumption, the influence of the bore distortion on the ring conformability and its impact on blow-by, friction and wear is highlighted in this study. Piston tilting, piston ring twist and surface roughness of the piston ring and liner have been taken into consideration.

Operation of a Two-Stroke, Spark-Ignition Engine on a Non-Conventional Lubricant

2017 ◽  
Author(s):  
Jacob Ahles ◽  
Kyle Price ◽  
Brian Eggart ◽  
Scott A. Miers ◽  
Andrew Wiegand ◽  
...  
Keyword(s):  
Power Density ◽  
Cost Effective ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Combustion Stability ◽  
Engine Oil ◽  
Test Duration ◽  
Spark Plug ◽  
Military Applications ◽  
The Impact

Two-stroke engines are capable of providing very high power density levels in a cost effective, easy-to-maintain package. They are, however, typically susceptible to higher levels of hydrocarbon emissions, lower durability, and a shorter lifecycle when compared to four-stroke engines. These detriments are easily overlooked in some military applications where power density is paramount, but most commercial two-stroke engines require specialized consumable lubricant. Typical military applications strive to minimize their logistics “trails,” which includes minimizing the variety of fluids they require. As a result, there has been very limited success in fielding small two-stroke engines for military use. As a preliminary study, MIL-PRF-2104K Single Common Powertrain Lubricant (SCPL, a four-stroke heavy diesel engine oil) was utilized as the consumable lubricant (in place of conventional two-stroke oil) in a liquid-cooled, semi-direct fuel injected, spark-ignition, two-stroke engine. Empirical data was collected to study the impact of the oil on deposit build-up, power, wear, combustion stability, and fuel conversion efficiency. Over 147 hours of operation were logged and analyzed. The performance of the engine on SCPL was consistent with conventional two-stroke oil and showed no degradation over the test duration. Brake specific fuel consumption was not negatively impacted with SCPL. Increased deposit build-up in the exhaust ports and on the spark plugs were the primary negative impacts of the SCPL oil. Spark plugs with hotter classifications and modification of the oiling rate resulted in a reduction of soot accumulation and spark plug fouling.

scholarly journals Ethanol/Gasoline Blends as Alternative Fuel in Last Generation Spark-Ignition Engines: A Review on CO and HC Engine Out Emissions

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4034
Author(s):  
Paolo Iodice ◽  
Massimo Cardone
Keyword(s):  
Physicochemical Properties ◽  
Alternative Fuels ◽  
Experimental Studies ◽  
Alternative Fuel ◽  
Exhaust Emissions ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Spark Ignition Engines ◽  
The Impact

Among the alternative fuels existing for spark-ignition engines, ethanol is considered worldwide as an important renewable fuel when mixed with pure gasoline because of its favorable physicochemical properties. An in-depth and updated investigation on the issue of CO and HC engine out emissions related to use of ethanol/gasoline fuels in spark-ignition engines is therefore necessary. Starting from our experimental studies on engine out emissions of a last generation spark-ignition engine fueled with ethanol/gasoline fuels, the aim of this new investigation is to offer a complete literature review on the present state of ethanol combustion in last generation spark-ignition engines under real working conditions to clarify the possible change in CO and HC emissions. In the first section of this paper, a comparison between physicochemical properties of ethanol and gasoline is examined to assess the practicability of using ethanol as an alternative fuel for spark-ignition engines and to investigate the effect on engine out emissions and combustion efficiency. In the next section, this article focuses on the impact of ethanol/gasoline fuels on CO and HC formation. Many studies related to combustion characteristics and exhaust emissions in spark-ignition engines fueled with ethanol/gasoline fuels are thus discussed in detail. Most of these experimental investigations conclude that the addition of ethanol with gasoline fuel mixtures can really decrease the CO and HC exhaust emissions of last generation spark-ignition engines in several operating conditions.

Marketing China to U.S. travelers through electronic word-of-mouth and destination image: Taking Beijing as an example

2021 ◽  
pp. 135676672098786
Author(s):  
Li Ran ◽  
Luo Zhenpeng ◽  
Anil Bilgihan ◽  
Fevzi Okumus
Keyword(s):  
Quantitative Research ◽  
Behavioral Control ◽  
Strong Relationship ◽  
Tourism Industry ◽  
Destination Image ◽  
Perceived Behavioral Control ◽  
Online Data ◽  
Mediating Role ◽  
Study Results ◽  
The Impact

The tourism industry in China has grown significantly over the last two decades. Most of the growth, however, is fueled by domestic tourism. As one of the biggest tourism markets in the world, U.S. tourists might be reluctant to travel to China due to reasons such as unfamiliarity, cultural differences, visa requirements, and long flights. Building on the Theory of Planned Behavior (TPB) with relevant constructs, this research proposes that building a strong destination image via eWOM may influence the attitude and intention of U.S. travelers to visit Beijing. More specifically, the current research aims to examine the impact of eWOM and destination image on travel intention of tourists. This study used a quantitative research method and online data collection was conducted through Qualtrics. A total of 413 valid responses from U.S. residents were collected. The statistical software SPSS 21.0 and Mplus 7.0 were used to analyze the data. Study results show a strong relationship between eWOM utilitarian function and eWOM credibility, and eWOM credibility has a significant influence on destination image. Although there was no direct impact of destination image on tourists’ future travel intention, destination image plays a mediating role between eWOM credibility and perceived behavioral control (and tourists’ attitudes as well). Finally, perceived behavioral control and tourists’ attitudes mediate the impact of destination image on travel intention.

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