Experimental Study of a Variable Pressure Damper on Automotive Valve Motion

1996 ◽  
Author(s):  
Jin-Jang Liou ◽  
Grodrue Huang ◽  
Wensyang Hsu
Keyword(s):  
Experimental Study ◽  
Friction Coefficient ◽  
Friction Force ◽  
High Speed ◽  
Experimental Results ◽  
Variable Pressure ◽  
Friction Forces ◽  
Valve Spring ◽  
Valve Motion

Abstract A variable pressure damper (VPD) is used here to adjusted the friction force on the valve spring to investigate the relation between the friction force and the valve bouncing phenomenon. The friction force on the valve spring is found experimentally, and the corresponding friction coefficient is also determined. Dynamic valve displacements at different speeds with different friction forces are calibrated. Bouncing and floating of the valve are observed when the camshaft reaches high speed. From the measured valve displacement, the VPD is shown to have significant improvement in reducing valve bouncing distance and eliminating floating. However, experimental results indicate that the valve bouncing can not be eliminated completely when the camshaft speed is at 2985 rpm.

Experimental Study of a Variable Pressure Damper on an Automotive Valve Train

1998 ◽  
Vol 120 (2) ◽  
pp. 279-281 ◽  
Author(s):  
Jin Jang Liou ◽  
Grodrue Huang ◽  
Wensyang Hsu
Keyword(s):  
Experimental Study ◽  
Friction Force ◽  
Frictional Force ◽  
Component Separation ◽  
Experimental Results ◽  
Valve Train ◽  
Variable Pressure ◽  
Valve Spring ◽  
High Speeds ◽  
Speed Range

A variable pressure damper (VPD) is proposed here to adjusted the friction force on the valve spring to investigate the relation between the friction force and the valve train. Valve bounce, component separation, spring vibration are observed in the testing. The VPD is shown to have significant improvement in reducing valve bouncing distance and surge vibration under 2985 rpm. Also, experimental results indicate that the component separation becomes more imminent at high speeds with larger damping forces. Here, in certain speed range, a proper frictional force provided by VPD is shown to be able to eliminate bouncing completely without causing component separation.

Experimental Study of Turbulent Macroinstabilities in an Agitated System with Axial High-Speed Impeller and with Radial Baffles

1996 ◽  
Vol 61 (6) ◽  
pp. 856-867 ◽  
Author(s):  
Oldřich Brůha ◽  
Ivan Fořt ◽  
Pavel Smolka ◽  
Milan Jahoda
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
High Speed ◽  
Experimental Results ◽  
Turbulent Regime ◽  
Frequency Of Occurrence ◽  
Visualization Method ◽  
Entire Flow

The frequency of turbulent macroinstability occurrence was measured in liquids agitated in a cylindrical baffled vessel. As it has been proved by preceding experimental results of the authors, the stochastic quantity with frequency of occurrence of 10-1 to 100 s-1 is concerned. By suitable choosing the viscosity of liquids and frequency of impeller revolutins, the region of Reynolds mixing numbers was covered from the pure laminar up to fully developed turbulent regime. In addition to the equipment making it possible to record automatically the macroinstability occurrence, also the visualization method and videorecording were employed. It enabled us to describe in more detail the form of entire flow field in the agitated system and its behaviour in connection with the macroinstability occurrence. It follows from the experiments made that under turbulent regime of flow of agitated liquids the frequency of turbulent macroinstability occurrence is the same as the frequency of the primary circulation of agitated liquid.

An experimental study on the cryogenic face seal at different inlet pressures

2019 ◽  
Vol 234 (9) ◽  
pp. 1470-1481
Author(s):  
Guoyuan Zhang ◽  
Yangyang Zhao ◽  
Weigang Zhao ◽  
Xiutian Yan ◽  
Maotan Liang
Keyword(s):  
Friction Coefficient ◽  
Friction Force ◽  
High Speed ◽  
Fluid Pressure ◽  
Stable State ◽  
Test System ◽  
Leakage Rate ◽  
Mechanical Seals ◽  
Closing Force ◽  
The Difference

An experimental test system for cryogenic high-speed hydrodynamic non-contact mechanical seals is developed. Based on this system, the performances of seals under different working conditions are studied in detail in this paper. With the experimental results, the main performances of the seals (such as inlet and outlet temperatures, separated speed, face temperature, friction force, friction coefficient, leakage rate) are obtained, and the relationships of the performances with the inlet fluid pressure, the closing force and the rotational speed are discussed. The results show that the difference between the outlet and inlet temperatures decreases with increasing inlet fluid pressure. As the speed increases, the friction force varies little and remains at a constant value. The friction coefficient of the seal is approximately 0.12 and basically does not change with the speed. The leakage rate is also maintained at approximately 190 g/s. With the increase in the closing force, the friction at the seal’s face does not change greatly, which indicates that the friction at the face is always in a stable state with the seal’s closing force.

Experimental Study of Friction in a Pneumatic Actuator at Constant Velocity

1993 ◽  
Vol 115 (3) ◽  
pp. 575-577 ◽  
Author(s):  
Lee E. Schroeder ◽  
Rajendra Singh
Keyword(s):  
Experimental Study ◽  
Experimental Method ◽  
Friction Force ◽  
Constant Velocity ◽  
Sliding Friction ◽  
Pneumatic Actuator ◽  
Friction Forces ◽  
Friction Models ◽  
Semi Empirical ◽  
Force Data

This paper describes an experimental method of determining sliding friction forces in a pneumatic actuator. Several empirical and semi-empirical friction models are evaluated using measured friction force data. A repeatability study is also performed to qualitatively assess friction randomness and a change in friction regimes.

An experimental study of high-speed rotor supported by air bearings: test RIG and first experimental results

2006 ◽  
Vol 39 (8) ◽  
pp. 839-845 ◽  
Author(s):  
Guido Belforte ◽  
Terenziano Raparelli ◽  
Vladimir Viktorov ◽  
Andrea Trivella ◽  
Federico Colombo
Keyword(s):  
Experimental Study ◽  
High Speed ◽  
Experimental Results ◽  
Air Bearings ◽  
Test Rig

Experimental Study of Kick up Phenomenon in Thermosonic Wire-Bonding

2012 ◽  
Vol 160 ◽  
pp. 77-81
Author(s):  
Jing Jing Tian ◽  
Lei Han
Keyword(s):  
Image Processing ◽  
Experimental Study ◽  
High Speed ◽  
Gold Wire ◽  
Wire Bonding ◽  
Processing Method ◽  
Experimental Results ◽  
High Speed Camera ◽  
Depth Study ◽  
Thermosonic Wire Bonding

Kick-up phenomenon during looping is an important factor in thermosonic wire bonding. In this study, the loping process during wire bonding was recorded by using high-speed camera, and wire profiles evolution was obtained from images sequence by image processing method. With a polynomial fitting, the wire loop profiling was described by the curvature changing, and kick-up phenomenon on gold wire was found between the instant of 290th frame(0.0537s) to 380th frame (0.0703s), the change of curvature is divided into three phases, a looping phase, a mutation phase and a kick-up phase. While in the kick-up phase, the kick up phenomenon is the most obvious. These experimental results were useful for in-depth study of kick-up phenomenon by simulation.

Experimental Study on the Lubrication Behaviors of Seawater-Lubricated Thordon Bearings

2012 ◽  
Vol 500 ◽  
pp. 297-300
Author(s):  
You Qiang Wang ◽  
Wen Li Sun
Keyword(s):  
Experimental Study ◽  
Friction Coefficient ◽  
Tribological Properties ◽  
Experimental Studies ◽  
Experimental Results ◽  
Bearing Clearance ◽  
Increasing Load

Seawater lubricated thordon bearing is one of the most appropriate bearings widely used in submerged pump for drainage. The apparatus for studying the lubrication behaviors of the seawater lubricated thordon bearings has been devised and established in the paper. The experimental studies on the tribological properties of the thordon bearings have been conducted under different load and velocity using the apparatus. Effects of load and velocity on friction coefficient of the thordon bearings have been estimated. The experimental results show that the friction coefficient decreases with increasing velocity; the friction coefficient decreases gradually at first and then decreases sharpy with increasing load; the friction coefficient increases sharply with the rising temperature. The experimental results also indicate that there is an appropriate bearing clearance for which the friction coefficient is up to minimum.

Experimental Study on the Response Characteristics of Oilcans under High-Velocity Fragment Impact

2012 ◽  
Vol 510 ◽  
pp. 500-506
Author(s):  
Chang Hai Chen ◽  
Xi Zhu ◽  
Hai Liang Hou ◽  
Li Jun Zhang ◽  
Ting Tang
Keyword(s):  
Experimental Study ◽  
High Velocity ◽  
High Speed ◽  
Room Temperature ◽  
Experimental Results ◽  
Fuel Oil ◽  
High Speed Camera ◽  
Response Characteristics ◽  
Fuel Oils ◽  
The Impact

To explore the deflagration possibility of the warship cabin filled with fuel oil under impact of high-speed fragments in the condition of room temperature, experiments were carried out employing the small aluminium oilcans filled with fuel oil. Response processes of the oilcans were observed with the help of a high-speed camera. The disintegration as well as flying scattering of the oilcans were analyzed. The reasons for atomization of the fuel oils were presented. Finally, the deflagration possibility of warship oil cabin was analyzed. Results show that the pressure inside the oilcan is quite great under the impact of the high-speed fragment, which makes the oilcan disintegration and flying scattering. Simultaneously, fuel oils inside the oilcans are atomized quickly followed by ejected in front and back directions. Under the same condition as in present tests, deflagration will not occur for fuel oils used by warships. Experimental results will provide valuable references for the deflagration analysis of warship fuel oil cabins subjected to the impact of high-velocity fragments.

Effects of Ball’s Rolling, Gyroscopic, and Spin Slide in a Ball Bearing on Raceway’s Stress and Fatigue Life

2020 ◽  
Vol 142 (8) ◽  
Author(s):  
Zhuang Chen ◽  
Guanci Chen
Keyword(s):  
Fatigue Life ◽  
Friction Coefficient ◽  
Contact Mechanics ◽  
Friction Force ◽  
Ball Bearing ◽  
Equivalent Model ◽  
Element Calculation ◽  
Heavy Load ◽  
Friction Forces ◽  
Bearing Life

Abstract The motions between the ball and raceway in a ball bearing involve rolling, gyroscopic, and spin slide. These complex motions result in the serious distribution of the friction force. Based on the contact mechanics in tribology, the friction force greatly affects stress and fatigue life. Thus, it is necessary to figure out the effects of the motions and its friction force of ball–raceway contact on the fatigue life of a ball bearing. In this paper, first, the equivalent model of ball–raceway contact was studied and established for the convenience of finite element calculation. Second, the contact mechanics considering the friction force with the friction coefficient from 0 to 0.3 was computed. The influences of the motions and its friction forces of ball–raceway contact on the raceway’s stress were analyzed. Third, based on different structure fatigue life algorithms, the raceway’s fatigue life of the cases with the friction coefficient 0, 0.05, 0.1, and 0.3 were studied. The raceway’s fatigue life based on ISO 281-2007 bearing life theory is studied. Results show that the friction force on the contact surface has some influence on the stress and fatigue life to a certain extent. Especially, the ball’s spin has the greatest influence on the stress distribution and fatigue life of the raceway. Thus, for the cases of heavy load and high friction coefficient, the effect of the friction force of ball–raceway contacts cannot be neglected.

Experimental Study on the Tribological Properties of Water-Lubricated Rubber Bearings

2011 ◽  
Vol 291-294 ◽  
pp. 1454-1457 ◽  
Author(s):  
You Qiang Wang ◽  
Mei Shu Wang
Keyword(s):  
Experimental Study ◽  
Friction Coefficient ◽  
Tribological Properties ◽  
Experimental Studies ◽  
Experimental Results ◽  
Bearing Clearance ◽  
Tribological Behaviors ◽  
Rubber Bearing ◽  
Rubber Bearings ◽  
Increasing Load

Water lubricated rubber bearing is one of the most appropriate bearings widely used in submerged pump for drainage. The apparatus for studying the tribological behaviors of the water lubricated rubber bearings has been devised and established in the paper. The experimental studies on the tribological properties of the rubber bearings have been conducted under different load and velocity using the apparatus. Effects of load and velocity on friction coefficient of the rubber bearings have been estimated. The experimental results show that the friction coefficient decreases with increasing velocity; the friction coefficient increases at first and then decreases with increasing load; the friction coefficient increases sharply with the rising temperature. The experimental results also indicate that there is an appropriate bearing clearance which the friction coefficient is minimum.

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