The Friction Reduction With a New Two-Piece Spring Retainer Design and Light Weight Valve Train Components in SI Engines

2004 ◽  
Author(s):  
Thomas Brinkmann ◽  
Jens Gaertner ◽  
Klaus Gebauer
Keyword(s):  
Friction Reduction ◽  
Valve Train ◽  
Pollutant Emissions ◽  
Valve Lift ◽  
Lubricating Oil ◽  
Measurement Equipment ◽  
Light Weight ◽  
Valve Spring ◽  
Axial Forces ◽  
Train Of Four

The reduction of friction in the valve train of four-stroke combustion engines is a promising opportunity to decrease fuel consumption and to improve pollutant emissions. The possibilities are reviewed by comparing light weight and newly developed components. The friction in the valve train causes a loss from the BMEP by about 0.2 to 0.4 bar. To measure friction forces in this range requires constant and well maintained environmental conditions. The viscosity as well as the pressure and temperature of the lubricating oil have a big influence on the friction. Due to the valve spring forces a strong fluctuation of the cam torque appears. This makes it very demanding to set up the measurement equipment in a correct way. Measurement equipment which is able to gauge with sufficient accuracy may be overloaded by the effects caused by the spring forces. Based on this special care is necessary during the first ramp up of the cylinder head. It has to be modified to avoid overloading the measurement equipment. One possibility to achieve lower friction between the valve stem and the valve guide is the reduction of the lateral forces which are caused by the asymmetry of the valve spring. Using recently new developed components these detrimental forces within a valve train can be reduced which leads to lower friction losses. In addition the wear between the valve train components can be reduced. In detail this can be accomplished by using two-piece spring retainer which allows a tilted position of the spring end during the valve lift and by this only allow axial forces to act onto the valve. The friction in a valve train using a direct acting mechanical tappet is mainly caused by the sliding contact of the cam on the tappet face. To lower the friction in this area the spring forces have to be reduced. This requires valve train components with lower masses and weaker springs. Therefore valves, spring retainers and tappets made from light weight alloys where developed. The mass of these light weight components could be reduced by more than 50%. Detailed measurements are performed and the results will be presented. As a conclusion it can be seen, what light weight components in the valve train of four stroke engines can contribute to a torque reduction in innovative valve trains.

Modeling of a Finger-Follower Cam System With Verification in Contact Forces

1993 ◽  
Author(s):  
Wensyang Hsu ◽  
Albert P. Pisano
Keyword(s):  
Constraint Equation ◽  
Contact Forces ◽  
Valve Train ◽  
Dynamic Responses ◽  
Valve Lift ◽  
Distributed Parameter ◽  
Contact Points ◽  
Frictional Forces ◽  
Contact Position ◽  
Force Data

Abstract A lumped/distributed-parameter, dynamic model is developed to investigate the dynamic responses of a finger-follower valve train with the effects of an oscillating pivot, frictional forces between sliding surfaces, and a hydraulic lash adjuster. Based on the measured force data at low speed, an algorithm is derived to determine the dynamic Coulomb friction coefficients around maximum valve lift simultaneously at three contact points. A constraint equation is formulated to find the contact position between the cam and the follower kinematically. This makes it possible for the model to simulate the dynamic response of the cam system when the pivot is moving. A hydraulic lash adjuster acting as the pivot of the follower is also modeled with the effects of oil compressibility and oil refill mechanism. The model is numerically integrated and shown to have good agreement between simulation results and experimental data of contact forces at three different speeds. The maximum operating speed is limited by valve toss, loss contact between components. The model predicts toss between the hydraulic lash adjuster and the follower at 2535 rpm, and experiment indicates toss starting at 2520 rpm of camshaft speed.

Tetrahedral Amorphous Carbon Coatings for Friction Reduction of the Valve Train in Internal Combustion Engines

2014 ◽  
Vol 16 (10) ◽  
pp. 1226-1233 ◽  
Author(s):  
Andreas Götze ◽  
Stefan Makowski ◽  
Tim Kunze ◽  
Matthias Hübner ◽  
Hans Zellbeck ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Internal Combustion Engines ◽  
Internal Combustion ◽  
Friction Reduction ◽  
Valve Train ◽  
Combustion Engines ◽  
Carbon Coatings ◽  
Tetrahedral Amorphous Carbon ◽  
Amorphous Carbon Coatings

scholarly journals Tribology Properties of Synthesized Multiscale Lamellar WS2 and Their Synergistic Effect with Anti-Wear Agent ZDDP

2019 ◽  
Vol 10 (1) ◽  
pp. 115 ◽  
Author(s):  
Na Wu ◽  
Ningning Hu ◽  
Jinhe Wu ◽  
Gongbo Zhou
Keyword(s):  
Friction Coefficient ◽  
Synergistic Effect ◽  
Solid Phase ◽  
Friction Reduction ◽  
Lubricating Oil ◽  
Solid Phase Reaction ◽  
Phase Reaction ◽  
Wear Properties ◽  
Base Oil ◽  
Electron Probe Micro Analyzer

The microscale/nanoscale lamellar-structure WS2 particles with sizes of 2 µm and 500 nm were synthesized by solid-phase reaction method and characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The synergies between microscale/nanoscale WS2 particles and ZDDP as lubricating oil additives was evaluated by means of UMT-2 tribometer at room temperature. The wear scars were examined with SEM and electron-probe micro-analyzer (EPMA). The results show that the anti-wear properties were improved and the friction coefficient was greatly decreased with the simultaneous addition of WS2 particles and ZDDP, and the largest reduction of friction coefficient was 47.2% compared with that in base oil. Moreover, the presence of ZDDP additive in the lubricant further enhances the friction-reduction and anti-wear effect of microscale/nanoscale WS2. This confirms that there is a synergistic effect between WS2 particles and ZDDP.

scholarly journals On Friction Reduction by Surface Modifications in the TEHL Cam/Tappet-Contact-Experimental and Numerical Studies

Coatings ◽  
2019 ◽  
Vol 9 (12) ◽  
pp. 843 ◽  
Author(s):  
Max Marian ◽  
Tim Weikert ◽  
Stephan Tremmel
Keyword(s):  
Surface Characterization ◽  
Surface Engineering ◽  
New Technologies ◽  
Surface Modifications ◽  
Operating Conditions ◽  
Friction Reduction ◽  
Valve Train ◽  
Friction Behavior ◽  
Fluid Friction ◽  
Wide Range

The overall energy efficiency of machine elements and engine components could be improved by using new technologies such as surface modifications. In the literature, surface engineering approaches like micro-texturing and the application of diamond-like carbon (DLC) coatings were frequently studied separately, with focus on a specific model contact and lubrication conditions. The contribution of the current study is to elucidate and compare the underlying friction reduction mechanisms of the aforementioned surface modifications in an application-orientated manner. The study applied the operating conditions of the thermo-elastohydrodynamically lubricated (TEHL) cam/tappet-contact of the valve train. Therefore, tribological cam/bucket tappet component Stribeck tests were used to determine the friction behavior of ultrashort pulse laser fabricated microtextures and PVD/PECVD deposited silicon-doped amorphous carbon coatings. Moreover, advanced surface characterization methods, as well as numerical TEHL tribo-simulations, were utilized to explore the mechanisms responsible for the observed tribological effects. The results showed that the DLC-coating could reduce the solid and fluid friction force in a wide range of lubrication regimes. Conversely, micro-texturing may reduce solid friction while increasing the fraction of fluid friction.

Novel Surface Treat Technology for Improving Wear-Resistant Properties of Cylinder Liner

2010 ◽  
Vol 168-170 ◽  
pp. 2387-2390 ◽  
Author(s):  
Zhi Hai Cai ◽  
Ping Zhang ◽  
Qingqiang Zeng
Keyword(s):  
High Temperature ◽  
Cylinder Liner ◽  
Complex Surface ◽  
Friction Reduction ◽  
Lubricating Oil ◽  
Bench Test ◽  
Standard Samples ◽  
Treatment Technology ◽  
Laser Quenching ◽  
Surface Laser

In order to solve the problem of wear-out–failure of diesel engine cylinder, the laser-quenching and low temperature ion sulfurizing complex surface treatment technology was operated on the surface of 42MnCr52 steel. And the tribological properties of the complex layer were investigated。Experimental results indicated that the complex layer is composed of soft surface sulphide layer and sub-surface laser-quenching harden layer, represents excellent friction-reduction and wear-resistance performance at high temperature. The synergistic effect of the laser quenching-sulphide layer resulted in 20% increase in hardness, 10% reduction in friction coefficient and 50% reduction in wear weight loss, respectively, compared with those of the standard samples. The bench-test further demonstrated that this technology can improve the lubricating condition between cylinder and piston ring, and reduce both abnormity wear when the lubricating oil is deficiency at the time of start-up and sticking wear at high temperature during the operating period, and then prolong the service life of engine.

scholarly journals Research Progress of Nano Copper Lubricant Additives on Engineering Tribology

Metals ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 2006
Author(s):  
Junde Guo ◽  
Yingxiang Zhao ◽  
Biao Sun ◽  
Puchao Wang ◽  
Zhijie Wang ◽  
...  
Keyword(s):  
Lubricant Additive ◽  
Friction Reduction ◽  
Research Progress ◽  
Lubricating Oil ◽  
Self Healing ◽  
Boundary Slip ◽  
Copper Particles ◽  
Oil Additives ◽  
Engineering Significance ◽  
Lubricating Oil Additives

Nanoparticles have as characteristics super sliding, extreme pressure, self-healing, etc., which can improve the friction reduction and anti-wear performance of sliding components, when used as lubricating oil additives. Nano-copper particles have a good synergistic effect with other antifriction agents, anti-wear agents, antioxidants and grease additives because of their low shear strength and grain boundary slip effect, showing a better anti-friction and anti-wear effect. However, nanoparticles are prone to conglomerate, and this causes a bottleneck in the application of dispersant for nano-copper in a lubricating oil system. The regulation of nanosized effect and surface properties has great engineering significance in compensating for the precision in manufacturing accuracy. This paper comprehensively reviews the tribological research progress of nano-copper as a lubricant additive, which provides a reference to the application of nano-copper particles as lubricating oil additives on engineering tribology.

Friction Reduction of Oil-Impregnated Sintered Bearings by Surface Texturing

2020 ◽  
Vol 142 (9) ◽  
Author(s):  
Atsushi Korenaga ◽  
Hiroki Mano ◽  
Ayako Omura ◽  
Tsuguyori Ohana ◽  
Shinobu Aso ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Surface Texturing ◽  
Friction Reduction ◽  
Lubricating Oil ◽  
Eccentricity Ratio ◽  
Bearing Surface ◽  
Plateau Region ◽  
Bearing Clearance ◽  
Attitude Angle ◽  
Rounded Rectangle

Abstract In this study, to reduce the friction of oil-impregnated sintered bearings, rounded-rectangle dimples are processed on the bearing surface and the bearing properties are examined. The dimpled bearings achieved lower friction than the flat bearings without dimple processing. To investigate the mechanism of friction reduction of the dimpled bearings, the friction coefficient, the eccentricity ratio, and the attitude angle of the bearings were measured. As a result, the dimpled bearings showed a larger eccentricity ratio and a smaller attitude angle than the flat bearings. In addition, the attitude angles of the dimpled bearings were negative in some cases. The reason for the reduced friction of the dimpled bearings is presumed to be that the extent of the lubricating oil in the bearing clearance was narrower, while the dimple enabled a sufficient amount of lubricating oil to be supplied to the plateau region.

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.

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