The Experts below are selected from a list of 861 Experts worldwide ranked by ideXlab platform
I. Tanimoto - One of the best experts on this subject based on the ideXlab platform.
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Wear mechanism of high wear-resistant materials for automotive valve trains
Wear, 1991Co-Authors: M Kano, I. TanimotoAbstract:Automotive engine valve train wear conditions have to be very rigorous owing to higher contact pressures, the presence of boundary lubrication, lower allowable wear limits and other factors. In an effort to develop higher wear-resistant materials to meet these requirements, analyses were made of the material properties and wear morphology of several kinds of wear-resistant materials, namely ferro-based sintered powder metals, alloyed cast irons and silicon nitride ceramics. These materials were evaluated in engine motoring tests as Rocker Arm cam followers mated with low alloy chilled cast iron camshafts and an examination was made of their wear-resistant properties. The results suggested that the wear mechanism was controlled by fatigue and ploughing wear. On the basis of this analysis, Nissan has developed cam and follower systems which combine chilled cast iron camshafts with Rocker Arm followers made of high wear-resistant materials. © 1991.
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Wear resistance properties of ceramic Rocker Arm pads
Wear, 1991Co-Authors: M Kano, I. TanimotoAbstract:Abstract Rocker Arm pads made of silicon nitride ceramics have been adopted in automotive engines in recent years, especially in taxi engines which exhibit severe wear in the cam and follower system. In this research, measurements of wear depth, observations of worn surface morphologies and analyses of lubrication films were performed for cam noses and their mating Rocker Arm pads following a series of engine bench tests. The results confirmed the superior wear resistance of silicon nitride pads for LPG taxi engines and it was found that excessive calcium and phosphorus adsorptions on contact surfaces lubricated with diesel engine grade oil contained primary type zinc dialkyldithiophosphate and large amounts of calcium detergent. The excessive adsorption of some additives caused the micro-pits observed on the cam noses following every test conducted with that grade of oil. It is thought that the pits were formed by acid corrosion following mechanochemical reactions.
M Kano - One of the best experts on this subject based on the ideXlab platform.
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Wear mechanism of high wear-resistant materials for automotive valve trains
Wear, 1991Co-Authors: M Kano, I. TanimotoAbstract:Automotive engine valve train wear conditions have to be very rigorous owing to higher contact pressures, the presence of boundary lubrication, lower allowable wear limits and other factors. In an effort to develop higher wear-resistant materials to meet these requirements, analyses were made of the material properties and wear morphology of several kinds of wear-resistant materials, namely ferro-based sintered powder metals, alloyed cast irons and silicon nitride ceramics. These materials were evaluated in engine motoring tests as Rocker Arm cam followers mated with low alloy chilled cast iron camshafts and an examination was made of their wear-resistant properties. The results suggested that the wear mechanism was controlled by fatigue and ploughing wear. On the basis of this analysis, Nissan has developed cam and follower systems which combine chilled cast iron camshafts with Rocker Arm followers made of high wear-resistant materials. © 1991.
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Wear resistance properties of ceramic Rocker Arm pads
Wear, 1991Co-Authors: M Kano, I. TanimotoAbstract:Abstract Rocker Arm pads made of silicon nitride ceramics have been adopted in automotive engines in recent years, especially in taxi engines which exhibit severe wear in the cam and follower system. In this research, measurements of wear depth, observations of worn surface morphologies and analyses of lubrication films were performed for cam noses and their mating Rocker Arm pads following a series of engine bench tests. The results confirmed the superior wear resistance of silicon nitride pads for LPG taxi engines and it was found that excessive calcium and phosphorus adsorptions on contact surfaces lubricated with diesel engine grade oil contained primary type zinc dialkyldithiophosphate and large amounts of calcium detergent. The excessive adsorption of some additives caused the micro-pits observed on the cam noses following every test conducted with that grade of oil. It is thought that the pits were formed by acid corrosion following mechanochemical reactions.
David Eovaldi - One of the best experts on this subject based on the ideXlab platform.
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Analysis and Customization of Rocker Arm Joint Sliding Velocity
Journal of Engineering for Gas Turbines and Power, 2009Co-Authors: Bruce Geist, David EovaldiAbstract:This paper examines how the sliding motion between a Rocker Arm and a valve stem tip can be adjusted by reshaping the Rocker pad surface. The valve tip is assumed flat, and the Rocker Arm and valve stem are assumed to lie in a common plane. It is shown that the rubbing velocity between a Rocker Arm and a valve stem tip, as well as the curvature of the Rocker Arm pad, may be determined from two features of the contact: (I) the contact point path between the Rocker Arm and the valve stem tip and (2) the angle that the valve stem tip makes with the line connecting the Rocker pivot to the zero-lift point of contact. An algorithm is presented for determining a Rocker Arm surface from a prescribed contact point path and valve angle. The derived technique enables customization of Rocker Arm pad curvature and Rocker Arm joint sliding velocity.
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Analysis and Customization of Rocker Arm Joint Sliding Velocity
ASME 2008 Internal Combustion Engine Division Spring Technical Conference, 2008Co-Authors: Bruce Geist, David EovaldiAbstract:This paper examines how the sliding motion between a Rocker Arm and valve stem tip can be adjusted by reshaping the Rocker pad surface. The valve tip is assumed flat, and the Rocker Arm and valve stem are assumed to lie in a common plane. It is shown that the rubbing velocity between a Rocker Arm and valve stem tip, as well as the curvature of the Rocker Arm pad, may be determined from two features of the contact: 1) the contact point path between Rocker Arm and valve stem tip and 2) the angle that the valve stem tip makes with the line connecting the Rocker pivot to the zero-lift point of contact. An algorithm is presented for determining a Rocker Arm surface from a prescribed contact point path and valve angle. The derived technique enables customization of Rocker Arm pad curvature and Rocker Arm joint sliding velocity.Copyright © 2008 by Chrysler LLC
Bruce Geist - One of the best experts on this subject based on the ideXlab platform.
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Analysis and Customization of Rocker Arm Joint Sliding Velocity
Journal of Engineering for Gas Turbines and Power, 2009Co-Authors: Bruce Geist, David EovaldiAbstract:This paper examines how the sliding motion between a Rocker Arm and a valve stem tip can be adjusted by reshaping the Rocker pad surface. The valve tip is assumed flat, and the Rocker Arm and valve stem are assumed to lie in a common plane. It is shown that the rubbing velocity between a Rocker Arm and a valve stem tip, as well as the curvature of the Rocker Arm pad, may be determined from two features of the contact: (I) the contact point path between the Rocker Arm and the valve stem tip and (2) the angle that the valve stem tip makes with the line connecting the Rocker pivot to the zero-lift point of contact. An algorithm is presented for determining a Rocker Arm surface from a prescribed contact point path and valve angle. The derived technique enables customization of Rocker Arm pad curvature and Rocker Arm joint sliding velocity.
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Analysis and Customization of Rocker Arm Joint Sliding Velocity
ASME 2008 Internal Combustion Engine Division Spring Technical Conference, 2008Co-Authors: Bruce Geist, David EovaldiAbstract:This paper examines how the sliding motion between a Rocker Arm and valve stem tip can be adjusted by reshaping the Rocker pad surface. The valve tip is assumed flat, and the Rocker Arm and valve stem are assumed to lie in a common plane. It is shown that the rubbing velocity between a Rocker Arm and valve stem tip, as well as the curvature of the Rocker Arm pad, may be determined from two features of the contact: 1) the contact point path between Rocker Arm and valve stem tip and 2) the angle that the valve stem tip makes with the line connecting the Rocker pivot to the zero-lift point of contact. An algorithm is presented for determining a Rocker Arm surface from a prescribed contact point path and valve angle. The derived technique enables customization of Rocker Arm pad curvature and Rocker Arm joint sliding velocity.Copyright © 2008 by Chrysler LLC
Eckhard A. Groll - One of the best experts on this subject based on the ideXlab platform.
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A comprehensive model for an oil-free carbon dioxide compressor using Sanderson Rocker Arm Motion (S-RAM) driving mechanism.
2017Co-Authors: Bin Yang, Orkan Kurtulus, Eckhard A. GrollAbstract:The multi-piston axial reciprocating compressor using the Sanderson-Rocker Arm Motion (S-RAM) mechanism is expected to have high volumetric efficiencies compared to conventional reciprocating compressors due to the application of a new type of seal to prevent the in-cylinder refrigeration gas leaking through the clearance between piston and cylinder wall. In addition, the compressor is expected to have high energy efficiencies compared to swash-plate/wobble-plate compressors due to reduced friction using the S-RAM mechanism and a near perfect linear motion of the piston inside the cylinder. Furthermore, the compressor capacity can be controlled by adjusting the piston stroke instead of compressor speed to meet the requirements of the delivered mass flow rate in the field. A comprehensive simulation model for a prototype reciprocating compressor using the S-RAM mechanism has been developed. The natural refrigerant carbon dioxide (CO2) is used as the working fluid. The comprehensive model is comprised of a kinematics model, compression process model, dynamics model and an overall energy balance model. In the kinematics model, the movement of the piston is given including its displacement, velocity and acceleration. In the compression process model, the system of governing equations is solved to obtain the instantaneous refrigerant temperature and pressure inside the cylinder. A new leakage model for the rubber-like seal is incorporated into the compression process model. The variations of suction and discharge valve movements with respect to driving shaft rotational angle are also revealed. The values of the cylinder wall temperature, the actual suction and discharge temperatures in the connecting pipes,which are required to initiate the solving of the compression process model,are given by the overall energy balance. A lumped temperature assumption is employed in the overall energy balance model to assume there is no temperature gradient in each compressor component at steady-state. The dynamics model uses the in-cylinder refrigerant pressure determined from the solution of the compression process model to calculate the forces/moments of the driving mechanism. The whole simulation model is numerically solved using RKF45 and Broyden’s method within a specified convergence range.
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An integrated model for an oil free carbon dioxide compressor using Sanderson-Rocker Arm motion (S-RAM) mechanism.
2016Co-Authors: Bin Yang, Orkan Kurtulus, Eckhard A. GrollAbstract:The multi-piston axial reciprocating compressor using the Sanderson-Rocker Arm Motion (S-RAM) mechanism is expected to have high volumetric efficiencies due to the application of a new type of seal to prevent the in-cylinder refrigeration gas leaking through the clearance between piston and cylinder wall. The stroke of the compressor can be controlled by adjusting the inclination angle between the connecting shaft and machine driving shaft. This allows the control of the delivered refrigerant mass flow rate to match the capacity requirement in the field. A comprehensive simulation model to predict the performance of a prototype reciprocating compressor using the SRAM mechanism has been developed. The natural refrigerant carbon dioxide (CO2) is used as the working fluid. The comprehensive model is comprised of a kinematics model, compression process model and an overall energy balance model. In the kinematics model, the movement of the piston is given including its displacement, velocity and acceleration. It is found that the moving path of the center of the ball in the ball-socket joint is moving around a corresponding cylinder centerline with a ‘figure 8’ motion instead of moving along the cylinder centerline. In the compression process model, the system of governing equations is solved, which incorporates a valve sub-model, leakage sub-model and gas pulsation sub-model. The classical 4th order Runge-Kutta method and Broyden’s method are employed to solve the non-linear system of equations to find the in-cylinder refrigerant state (temperature, pressure) at each rotational angle of the machine driving shaft. The variations of suction and discharge valve movements with respect to drive shaft rotational angle are also given. The values of the cylinder wall temperature, the actual suction and discharge temperatures in the connecting pipes are required to initiate the solving of the compression process model. These temperatures are solved simultaneously by incorporating the overall energy balance model with the compression process model. A lumped temperature assumption is employed in the overall energy balance model to assume there is no temperature gradient in each compressor component at steady-state.
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Modeling of an Oil-Free Carbon Dioxide Compressor Using Sanderson-Rocker Arm Motion (S-RAM) Mechanism
IOP Conference Series: Materials Science and Engineering, 2015Co-Authors: Bin Yang, Orkan Kurtulus, Eckhard A. GrollAbstract:A simulation model to predict the performance of a prototype CO2 compressor is presented. This prototype compressor employs the Sanderson-Rocker Arm Motion (S-RAM) mechanism, which converts the rotary motion of the shaft into a linear reciprocating motion of the cylinders. The piston stroke can be variable by changing the incline angle between the connecting rod and compressor main shaft centerline. The compressor model is mainly composed of two main sub-models simulating the kinematics of the drive mechanism and the compression process. A valve sub-model is included in the compression process model.
