Reducing the Level of Engine Oil Reflux into the Crankcase Ventilation System of a V-engine

2018 ◽  
Vol 4 (1) ◽  
Keyword(s):  
Ventilation System ◽  
Engine Oil ◽  
Crankcase Ventilation

Liner Design to Reduce Unburned Hydrocarbon Exhaust Emissions

2018 ◽  
Author(s):  
Paul S. Wang ◽  
Allen Y. Chen
Keyword(s):  
Natural Gas ◽  
Ventilation System ◽  
Hydrocarbon Emissions ◽  
Tracer Technique ◽  
Oil Consumption ◽  
Natural Gas Engines ◽  
Unburned Hydrocarbon ◽  
Crankcase Ventilation ◽  
Unburned Fuel ◽  
Careful Design

Large natural gas engines that introduce premixed fuel and air into the engine cylinders allow a small fraction of fuel to evade combustion, which is undesirable. The premixed fuel and air combust via flame propagation. Ahead of the flame front, the unburned fuel and air are driven into crevices, where conditions are not favorable for oxidation. The unburned fuel is a form of waste and a source of potent greenhouse gas emissions. A concept to vent unburned fuel into the crankcase through built-in slots in the liner during the expansion stroke has been tested. This venting process occurs before the exhaust valve opens and the unburned fuel sent into the crankcase can be recycled to the intake side through a closed crankcase ventilation system. The increased communication between the cylinder and the crankcase changes the ring pack dynamics, which results in higher oil consumption. Oil consumption was measured using a sulfur tracer technique. Careful design is required to achieve the best tradeoff between reductions in unburned hydrocarbon emissions and oil control.

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.

On Blow-by Aerosol Sources in a Single-Cylinder Crankcase Environment

2021 ◽  
Author(s):  
N. Nowak ◽  
K. Scheiber ◽  
C. Stieler ◽  
M. T. Heller ◽  
J. Pfeil ◽  
...  
Keyword(s):  
Ventilation System ◽  
Formation Mechanisms ◽  
Minor Effect ◽  
Piston Rings ◽  
Bulk Oil ◽  
Single Cylinder ◽  
Aerosol Generation ◽  
Crankcase Ventilation ◽  
Aerosol Sources ◽  
Peak Pressures

Abstract Crankcase aerosol contributes to the particulate matter (PM) emissions of combustion engines equipped with an open crankcase ventilation system. In case of closed crankcase ventilation, the aerosol forms deposits that diminish engine efficiency, performance, and reliability. Such issues are best avoided by highly efficient filters combined with in-engine reduction strategies based on a quantitative understanding of aerosol sources and formation mechanisms in a crankcase environment. This paper reports key findings from a study of aerosol spectra in the range of 0.01 μm to 10 μm obtained from a 1.3-L single-cylinder engine under well-defined conditions. Supermicron particles were formed mainly by cooling jet break-up when the piston was positioned in TDC, while at BDC aerosol generation decreased by about 90 % because the oil jet was short and thus stable. Motoring the engine yielded an additional peak around 0.7 μm. It is associated with oil atomization at the piston rings and increased strongly with cylinder peak pressure. No significant contribution of the bearings could be identified at peak pressures below 116 bar. Engine speed had only a minor effect on aerosol properties. Operating the engine in fired mode increased the submicron aerosol concentration substantially, presumably because high(er) peak pressures boost aerosol generation at the piston rings, and because additional particles may have formed from recondensing oil vapor generated at hotspots. Soot or ash aerosols could not be identified in the crankcase aerosol, because they may have been integrated into the bulk oil.

Optimizing Crankcase Ventilation System of Gasoline Engine

2011 ◽  
Vol 58-60 ◽  
pp. 171-176
Author(s):  
Ming Jiang Hu
Keyword(s):  
Gasoline Engine ◽  
Ventilation System ◽  
Flow Characteristics ◽  
Gas Leakage ◽  
Working Model ◽  
Crankcase Ventilation ◽  
Analog Control ◽  
Test Platform ◽  
Fluid Properties ◽  
Test Result

Based on the design goals of the gasoline engine crankcase ventilation system, the features and the layout were described on the gasoline engine crankcase ventilation system, the working model was established on the gasoline engine crankcase ventilation system; using the fluid properties and the mathematical calculation method, the optimizing strategy was proposed on the piston gas leakage, the influencing factors were analyzed on the gasoline engine crankcase vacuum, the design strategy of the flow characteristics was developed on the PCV valve. Using analog control test platform of the gasoline engine, the tests were made on the piston gas leakage, the crankcase vacuum and PCV valve flow characteristics of the gasoline engine crankcase ventilation system. The test result showed that the optimized maximum piston leakage flow was 14L/min; the increasing rates of the optimized intake pipe and crankcase vacuum average were according 5.6% and 8.0%. This could indicate that the working model on the gasoline engine crankcase ventilation system was correct; the proposed strategies on the piston gas leakage, the crankcase vacuum and PCV valve flow characteristics were feasible in the gasoline engine crankcase ventilation system.

Thermodynamic analysis of working process effective indicators of a diesel engine with an open and closed crankcase ventilation system

Trudy NAMI ◽  
2022 ◽  
pp. 22-30
Author(s):  
A. A. Matveev ◽  
I. Kh. Israfilov ◽  
V. N. Nikishin ◽  
S. M. Andriyanov
Keyword(s):  
High Performance ◽  
Ventilation System ◽  
Experimental Studies ◽  
Practical Significance ◽  
Compression Ignition ◽  
Working Process ◽  
Compression Ignition Engine ◽  
System Effect ◽  
Automobile Engine ◽  
Crankcase Ventilation

Introduction (problem statement and relevance). This article provides up-to-date information analysis of the crankcase gases bypass effect from the crankcase ventilation system to the compression ignition engine intake. The paper considers the information on the variants of the crankcase ventilation systems of modern engines. The article reveals the necessity to analyze the engine working process at the design and development stage of a closed crankcase ventilation system. The legislative requirements for the implementation of the ventilation system to ensure safe environmental performance have been indicated. The purpose of the study was to assess both open and closed ventilation system effect on the crankcase space indicators, in particular, on the average specific fuel consumption, with reference to a high-performance automobile engine with compression ignition.Methodology and research methods. Theoretical and computational studies were carried out with the help of mathematical statistics and thermodynamics methods in a one-dimensional setting. The verification of the calculations reliability was carried out by comparing the simulation data and the results the internal combustion engine experimental studies.Scientific novelty and results. A thermodynamic model of a high-performance automobile engine compression ignition V8 CHN 12/13 with an open and closed ventilation system of the crankcase space has been developed. The model made it possible to evaluate the effect of crankcase gases bypass back to the engine cylinder intake.Practical significance. The developed thermodynamic models confirmed the insignificant effect on the working process of the V8 CHN 12/13 engine by bypassing crankcase gases back to the cylinder inlet. 

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.

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