Valve Train Dynamic Analysis and Digital Data Based Manufacturing of the Valve Spring

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.

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Optimum Positioning of FIP Drive System for Type-II BSVI Engine Based on Coupled 1D “Valve-Train - Chain Drive Dynamic Analysis

10.4271/2020-01-1020 ◽

2020 ◽

Author(s):

Kaarthic Kaundabalaraman ◽

Hemantkumar Rathi ◽

Jasvir Singh Bisht

Keyword(s):

Dynamic Analysis ◽

Drive System ◽

Valve Train ◽

Type Ii ◽

Chain Drive

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Dynamic analysis of a car engine valve train system

International Journal of Vehicle Noise and Vibration ◽

10.1504/ijvnv.2016.080138 ◽

2016 ◽

Vol 12 (3) ◽

pp. 229 ◽

Cited By ~ 6

Author(s):

Enrico Armentani ◽

Francesco Sbarbati ◽

Michele Perrella ◽

Roberto Guglielmo Citarella

Keyword(s):

Dynamic Analysis ◽

Valve Train ◽

Engine Valve ◽

Train System

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Modeling, Validation and Dynamic Analysis of Diesel Pushrod Overhead Bridged Valve Train

10.4271/2007-01-1256 ◽

2007 ◽

Author(s):

Tao (Tom) Xu ◽

Chungyao (Alex) Tang ◽

Huihua (Harry) Shen ◽

Michael King ◽

Mark Nowak ◽

...

Keyword(s):

Dynamic Analysis ◽

Valve Train

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

Journal of Mechanical Design ◽

10.1115/1.2826969 ◽

1998 ◽

Vol 120 (2) ◽

pp. 279-281 ◽

Cited By ~ 1

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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A NUMERICAL APPROACH TO CALCULATE CREEP IN ROLLER FOLLOWER VALVE TRAIN BASING ON FRICTION AND LUBRICATION MODELING

Transactions of the Canadian Society for Mechanical Engineering ◽

10.1139/tcsme-2015-0064 ◽

2015 ◽

Vol 39 (4) ◽

pp. 805-818 ◽

Cited By ~ 3

Author(s):

Muhammad Khurram ◽

Riaz Ahmad Mufti ◽

Muhammad Usman Bhutta ◽

Yousaf Habib ◽

Arslan Ahmed ◽

...

Keyword(s):

Film Thickness ◽

Dynamic Analysis ◽

Numerical Approach ◽

Mixed Lubrication ◽

Valve Train ◽

Normal Loading ◽

Oil Film ◽

Tangential Forces ◽

Motion Parameters ◽

Friction And Lubrication

A numerical approach basing on friction and lubrication analysis has been developed to determine the creep at cam/roller interface in end pivoted roller finger follower valve train. The kinematic and dynamic analysis at the geometrical mating surfaces of cam and roller follower has been carried out to predict the required instantaneous motion parameters and normal loading whereas the oil film thickness is determined using lubrication analysis. The tangential forces have been computed precisely using elastohydrodynamic and mixed lubrication concept for a complete cam cycle. At low camshaft operating speeds, the creep proves to be low whereas the creep increases significantly under the influence of high tangential loading at higher operating speeds.

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Dynamics Analysis and Cam Profile Optimal Design of the Valve Train in the Diesel Engine with High Specific Power

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.308-310.1636 ◽

2011 ◽

Vol 308-310 ◽

pp. 1636-1640 ◽

Cited By ~ 1

Author(s):

Li Wei Sun ◽

Tie Xiong Su ◽

Jun Feng Xu ◽

Qiang Wang ◽

Chun Long Xu ◽

...

Keyword(s):

Diesel Engine ◽

Optimal Design ◽

Dynamic Analysis ◽

Process Simulation ◽

Valve Train ◽

Specific Power ◽

Intake Port ◽

Working Process ◽

High Specific Power ◽

Cam Profile

The study carries out optimal design for the cam profile of the valve train in a high-specific-power diesel engine. The dynamic analysis on the original cam reveals that the original one, which leads to adequate fullness coefficient, is designed far from the material margins. The fullness coefficient and time area value are selected as the optimization objective, and the piecewise fucntion method is utilized to optimally design the cam profile. The restrictive contidons are applied to each section on the cam. Thus the function and the optimal coeficients are obtained. Then the dynamic analysis and working process simulation on the optimal valve train are carried out, and it proves that the dynamic and intake port performaces of the optimized one are greatly impoved.

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