• International Journal of Automotive Technology
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• v.8 no.2
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• pp.219-224
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• 2007

Recently, atmospheric contaminations has become worse due to the increased number of automobile. The PCV (Positive Crankcase Ventilation) valve acts as a flow control to allow re-combustion of blow-by gas by having it flow from a crankcase to an inlet manifold suction tube. Also, during the fabrication of the PCV valve, micro cracks may occur in the valve body and be extended under operation. The excessive stress distribution and crack initiation on the PCV valve body would bring an unstable blow-by gas flow rate control and would cause valve failure. The purpose of this study is to examine the crack affects on the stress and strain variations on the PCV valve according to the inlet and outlet manifold under differential pressures. From the results, we can explain the behavior of the crack extension for a safe condition of PCV valve.

• Journal of Power System Engineering
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• v.10 no.2
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• pp.68-74
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• 2006

In the development of new automobiles, the efforts to reduce environmental problems like air pollution have been risen. Blowby gas consists of about $20{\sim}35%$ of total amount of Hydrocarbon (HC), one of dangerous pollutants issuing from automobiles. A PCV valve is a very small component in an automotive engine but it is a very important part. Because that a PCV valve is used to control blowby gas and to recirculate it into a manifold automatically. Although it has very simple operating principle, designing a PCV valve is so difficult due to interaction between fluid and solid. In this study, our purpose is to develop a design program for a PCV valve and to verify its efficiency. Both Bernoulli equation and 4th order Runge-Kutta method were adopted to predict spool displacements and flow patterns. Comparing with experiments, it was found that both spool diameters and displacements were predicted well, however, flow rates showed a little differences because of the assumption of non viscous flow.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.11a
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• pp.230-231
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• 2005

As environmental problems are important, automotive industries are developing various techniques to prevent air pollution. One of these is Positive Crankcase Ventilation (PCV) system. It removes blowby gas which includes about 30% hydrocarbon of total generated quantity. In this system, a PCV valve is attached in a manifold suction tube to control the flow rate of blowby gas which generates differently according to various operating conditions of an automotive engine. As this valve is very important, designers are feeling to design it because of both small size and high velocity. For this reason, we numerically investigated to understand both spool dynamic motion and internal fluid flow characteristics. As the results, spool dynamic characteristics, i.e. displacement, velocity, acting force, increase in direct proportion to the magnitude of differential pressure and indicate periodic oscillating motions. And, the velocity at the orifice region decreases according to the increase of differential pressure because of energy loss which is caused by the sudden decrease of flow area at the orifice region and the increase of flow volume in the front of spool head. Finally, the mass flow rate at the outlet decreases with the increase of spool displacement. We expect that PCV valve designers can easily understand fluid flow inside a PCV valve with our visual information for their help.

• 한국전산유체공학회:학술대회논문집
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• 2005.04a
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• pp.197-201
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• 2005

According to operating conditions of each engine, a PCV valve has various flow rates and pressure characteristic. In a developed country, it has been developing by a computational design simulation. But, Korean companies have no ability of technical design for a PCV valve. So, they depend on their experiments and copy the designs of foreign companies when they need to design new PCV valves. These problems cause increase of error rate and take much time. Hence, optimal design for a PCV valve is needed to secure for continuous competition against foreign automobile companies. In this study, we used 4th order Runge-Kutta method for the prediction of spool movements and applied Bernoulli's equation for the determination of flow area. A spool geometry and spool displacement were predicted to be satisfied in comparison with their experiment.

• Proceedings of the Korean Society of Marine Engineers Conference
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• 2005.06a
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• pp.228-232
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• 2005

Automobiles are very important as modern society is developed. Increase of the number of the automobiles cause environmental problem, that is, air pollution. So, many countries are adopting a environmental law. Automobile manufacturing companies have developing methods to prevent air pollution with increase of the efficiency of automotive engines. PCV(Positive Crankcase Ventilation) system which is one of them is made by the closed loop that consists of combustion chamber, crankcase, manifold suction tube and manifold. PCV valve is attached on manifold tube to control the flowrate of blowby gas. PCV valve is an important part in this system but it is difficult to design PCV valve which satisfies the required flowrate of blowby gas. In this study, our purpose is to help a PCV valve designer with the development of a design program. We used 4th order Runge-Kutta method and Bernoulli's equation to analyze the spool dynamic motion. By the comparison between our program and experiment, we think that a PCV designer can use our program in their work place.

• 한국전산유체공학회:학술대회논문집
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• 2005.10a
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• pp.223-227
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• 2005

A PCV valve is a part to control the flow rate of Blowby gas in a PCV system. A PCV system re-burns Blowby gas with fuel in a combustion chamber. Some gas enters to a crankcase room through the gap between piston ring and engine cylinder wall. This gas si called 'Blowby gas'. This gas causes many problems. In environmental view, Blowby gas includes about $25\~35\%$ hydrocarbon{HC) of total generated HC in an automobile. Hydrocarbon is a very harmful pollutant element in our life. In mechanical view, Blowby gas has some reaction with lubricant oil of crankcase room. Then, this causes lubricant oil contamination, crankcase corrosion and a decrease fo engine efficiency. Consequently, Blowby gas must be eliminated from a crankcase room. In this study, we simulated internal flow characteristics in a PCV valve according to spool dynamic behavior using local remeshing method And, we programmed our sub routine to simulate a spool dynamic motion. As results, spool dynamic behavior is periodically oscillated by the relationship between fluid force and elastic force of spring. And its magnitude is linearly increased by the differential pressure between inlet and outlet. Also, as spool is largely moved, flow area is suddenly decreased at orifice. For this reason, flow velocity is rapidly decreased by viscous effect.

• 한국가시화정보학회:학술대회논문집
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• 2005.12a
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• pp.111-116
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• 2005

An automobile engine has the Positive Crankcase Ventilation system (PCV system) for preventing air pollution as the environmental problem is important In this system, a PCV valve is the most important component to control the flow rate of Blowby gas which is generated by various engine powers. But, in the working place, the design of a PCV valve is very difficult because of interaction between fluid and solid motions. In this study, we investigated fluid flow characteristics using re-meshing method of a CFD technique to simulate spool behavior. As the results, a spool is periodically oscillated with time and is largely oscillated in proportion to the differential pressure between inlet and outlet. And, although the velocity at the orifice increases with the differential pressure, the flow rate of the outlet decreases. This research may give PCV designers visual flow information to help them

• Journal of the Korean Society of Visualization
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• v.10 no.1
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• pp.15-20
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• 2012

PCV(Positive Crankcase Ventilation) system is designed to remove blowby gas. In this system, a PCV valve is attached in a manifold suction tube to control the flow rate of blowby gas which generates various operating conditions of an automotive engine. As this valve plays a crucial role, the demand in its design is high owing to the small size and high velocity. For this reason, a numerical investigation was carried out to understand both the spool dynamic motion and internal fluid flow characteristics. As a result, the spool dynamic characteristics(i.e. displacement, velocity, acting force), increase in direct proportion to the magnitude of the pressure difference and indicate periodic oscillating motions. Moreover, the velocity at the orifice region decreases according to the increase in differential pressure due to energy loss caused by the sudden decrease of flow area at the orifice region and the increase of flow volume in front of the spool head. Finally, the mass flow rate at the outlet decreases with the increase of spool displacement.

• Journal of the Korean Society of Safety
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• v.20 no.1 s.69
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• pp.36-41
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• 2005

PCV(Positive Crankcase Ventilation) valve acts as a flow control valve to get a re-combustion of blow-by gas by having it flow from a crankcase to an inlet manifold suction tube. The blow-by gas of the crankcase should be eliminated or taken properly because it cause corrosion to critical parts, and contributes to increase crankcase pressure that can cause a drop in efficiency. The excessive stress and strain on the PCV valve that remove these harmful gas would be bring the difficult on the flow rate control and failure of the valve. Those condition inevitably induce the accident. Therefore, this study purpose is FEM evaluation of the stresses and deformation in the X3 PCV model according to the change of the differential pressure between inlet and outlet. From results, the maximum equivalent stresses increased linearly according to the increase of the differential pressure at the about 50mm from the inlet position and were under the yield strength of the valve. And the deformations were relatively small regardless of the in-outlet differential pressure variation.

• Journal of Institute of Control, Robotics and Systems
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• v.13 no.3
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• pp.198-204
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• 2007

The modelling and design of the PCV(Pressure Control Valve) for passenger car CVT(Continuously Variable Transmission) are considered in this paper. For analysis and design, the simulation model of the PCV is derived by using commercial software, AMESim. For a good design of the PCV, the sensitivity analysis for design parameters is carried out and the static and dynamic characteristics of the developed PCV are experimented. The simulation and experimental results are presented to show the validity of the design process.