scholarly journals Modeling and NVH Analysis of a Full Engine Dynamic Model with Valve Train System

2020 ◽  
Vol 10 (15) ◽  
pp. 5145
Author(s):  
Xu Zheng ◽  
Xuan Luo ◽  
Yi Qiu ◽  
Zhiyong Hao
Keyword(s):  
Dynamic Model ◽  
Cylinder Head ◽  
Power Level ◽  
Valve Train ◽  
Depth Study ◽  
The Difference ◽  
Engine Dynamic ◽  
Noise Vibration ◽  
The Impact ◽  
Train System

The valve train system is an important source of vibration and noise in an engine. An in-depth study on the dynamic model of the valve train is helpful in understanding the dynamic characteristics of the valve train and improving the prediction accuracy of vibration and noise. In the traditional approaches of the dynamic analyses, the simulations of the valve train system and the engine are carried out separately. The disadvantages of these uncoupled approaches are that the impact of the cylinder head deformation to the valve train and the support and constraints of the valve train on the cylinder head are not taken into consideration. In this study, a full engine dynamic model coupled with a valve train system is established and a dynamic simulation and noise vibration harshness (NVH) analysis are carried out. In the coupled approach, the valve train system is simulated simultaneously with the engine, and the complexity of the model has been greatly increased. Compared with the uncoupled approach, more detailed dynamic results of the valve train can be presented, and the subsequent predictions of vibration and noise can also be more accurate. The acoustic results show that the difference from the experimental sound power level is reduced from 1.8 dB(A) to 0.9 dB(A) after applying the coupled approach.

A New Numerical Method for Developing the Lumped Dynamic Model of Valve Train

2015 ◽  
Vol 137 (10) ◽  
Author(s):  
Jie Guo ◽  
Yipeng Cao ◽  
Wenping Zhang ◽  
Xinyu Zhang
Keyword(s):  
Dynamic Model ◽  
Natural Frequencies ◽  
Valve Train ◽  
Frequency Range ◽  
Matching Method ◽  
Lumped Masses ◽  
Flexible Component ◽  
Train Vibration ◽  
Train System ◽  
Low Order

The dynamics of valve train is influenced by stiffness, size, and mass distribution of its components and initial valve clearance and so on. All the factors should be taken into consideration correctly by dynamic model and described qualitatively and quantitatively through mathematical variables. This paper proposes a new simplified method for valve train components, namely, mode matching method (MMM) for camshaft, pushrod, rocker arm, valve, and valve spring. In this method, the amount of lumped masses for each flexible component is determined based on its natural frequencies and the considered frequency range. As a result, the dynamic model of each component is required to match its low order modes within the considered frequency range. The basis of this method is that the contributions of each component to valve train vibration are mainly in the low order modes. The numerical model of valve train is verified by an experiment conducted on a motor driven valve train system.

INVESTIGATING THE ROLE OF WITHIN- AND BETWEEN-PATCH MOVEMENT IN A DYNAMIC MODEL OF DISEASE SPREAD

2020 ◽  
Vol 28 (04) ◽  
pp. 815-837
Author(s):  
KLOT PATANARAPEELERT
Keyword(s):  
Dynamic Model ◽  
Gravity Model ◽  
Transmission Rate ◽  
Human Mobility ◽  
Disease Spread ◽  
The Difference ◽  
Invasion Threshold ◽  
The Impact ◽  
Local Transmission

The impact of human mobility on the spreading of disease in a metapopulation is emphasized on interconnecting between patches, whereas the current volume of movement within the local population is usually neglected. Here, the role of internal commuters is taken into account by two means, a local transmission rate and the volume of internal commuters. Dynamic model of human mobility in the metapopulation with gravity coupling is presented. In conjunction with the disease spreading, the impact on invasion threshold and epidemic final size are analyzed. For two-patch model, we show that under fixing parameters in gravity model, the existence of invasion threshold depends on the difference of local transmission rates and the proportion of internal commuters between two patches. For a fully connected network with an identical transmission rate, the difference in patch final sizes is driven by patch distribution of internal commuters. By neglecting the effect of spatial variation in a simple core–satellite model, we show that the heterogeneity of internal commuters and gravity coupling induce a complex pattern of threshold, which depend mostly on the exponent in gravity model, and are responsible for the differences among local epidemic sizes.

A New Numerical Method for Developing the Lumped Dynamic Model of Valve Train

2014 ◽  
Author(s):  
J. Guo ◽  
Y. P. Cao ◽  
W. P. Zhang ◽  
X. Y. Zhang
Keyword(s):  
Dynamic Model ◽  
Natural Frequencies ◽  
Valve Train ◽  
Frequency Range ◽  
Matching Method ◽  
Lumped Masses ◽  
Flexible Component ◽  
Train Vibration ◽  
Train System ◽  
Low Order

The dynamics of valve train is influenced by stiffness, size and mass distribution of its components and initial valve clearance and so on. All the factors should be taken into consideration correctly by dynamic model and described qualitatively and quantitatively through mathematical variables. This paper proposes a new simplified method for valve train components, namely mode matching method (MMM) for camshaft, pushrod, rocker arm, valve and valve spring. In this method the amount of lumped masses for each flexible component is determined based on its natural frequencies and the considered frequency range. As a result, the dynamic model of each component is required to match its low order modes within the considered frequency range. The basis of this method is that the contributions of each component to valve train vibration are mainly in the low order modes. The numerical model of valve train is verified by an experiment conducted on a motor driven valve train system.

Assessment of Friction for Cam-Roller Follower Valve Train System Subjected to Mixed Non-Newtonian Regime of Lubrication

2012 ◽  
Author(s):  
A. Turturro ◽  
R. Rahmani ◽  
H. Rahnejat ◽  
C. Delprete ◽  
L. Magro
Keyword(s):  
Dynamic Model ◽  
Current Model ◽  
Fuel Efficiency ◽  
Valve Train ◽  
Design Parameters ◽  
Engine Fuel ◽  
Building Simulations ◽  
Model Combining ◽  
Cam Follower ◽  
Train System

The tribology of cam-roller follower conjunction is highly dependent on the engine type and working conditions. The interface experiences transient conditions due to variations in contact geometry and kinematics, as well as loading. These lead to instantaneous and capricious behavior of the lubricant through the contact, which determines the regime of lubrication. The resulting frictional characteristics are affected by the shear of the lubricant film and the interaction of rough surfaces themselves. Thus, specific analysis is required for any intended new engine configuration. Therefore, a tribo-dynamic model, combining valve train dynamics, contact kinematics and tribological analysis is required. An important issue is to develop a simple yet reliable and representative model to address the above mentioned pertinent issues. This would make for rapid scenario-building simulations which are critical in industrial design time-scales. The current model has been developed in response to the above mentioned requirements. A multi-body dynamic model for the valve train system based on the key design parameters is developed and integrated with an EHL tribological model for the cam-follower contact. To keep the model simple and easy to use and to avoid time-consuming computations, the analytical EHL model makes use of Grubin’s oil film thickness equation. Viscous and boundary contributions to friction are obtained as these account for the losses which adversely affect the engine fuel efficiency.

scholarly journals Study on Seismic Performance of Porcelain Pillar Electrical Equipment Based on Nonlinear Dynamic Theory

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Yaodong Xue ◽  
Yongfeng Cheng ◽  
Zhubing Zhu ◽  
Sheng Li ◽  
Zhenlin Liu ◽  
...  
Keyword(s):  
Theoretical Analysis ◽  
Dynamic Model ◽  
Electrical Equipment ◽  
Nonlinear Parameter ◽  
Seismic Excitation ◽  
Test Results ◽  
Nonlinear Seismic Response ◽  
Calculation Results ◽  
The Difference ◽  
The Impact

In order to consider the influence of nonlinear characteristics of porcelain pillar electrical equipment on the dynamic response under seismic excitation, a theoretical analysis method of nonlinear dynamics was raised to define the nonlinear parameter of the flange connection and establish a dynamic model of porcelain pillar electrical equipment. The theoretical analysis and the test results have a good degree of fitting, which verifies the correctness of the dynamic model and reveals the nonlinear seismic response law of the porcelain pillar equipment. According to the results, both the nonlinear calculation results of the displacement at the top end of the porcelain pillar and the stress at the bottom end of the porcelain pillar are smaller than the results in the linear calculation. The difference between them increases gradually with the increase of seismic excitation. The differences in displacement and stress at a seismic excitation of 0.5 g are 14.58% and 23.25%, respectively. When the nonlinear parameter increases to a certain value, the impact of maximum stress on the bottom of the porcelain pillar is very small and the change is not obvious. The research provides a theoretical reference for the seismic design of pillar electrical equipment.

Engine Valve Motion Simulated with Mechanical Dynamics

2012 ◽  
Vol 164 ◽  
pp. 429-432
Author(s):  
Zong Zheng Ma ◽  
Xin Li Wang
Keyword(s):  
High Frequency ◽  
Valve Train ◽  
Motion Simulation ◽  
Engine Valve ◽  
Valve System ◽  
Valve Motion ◽  
Mechanical Dynamics ◽  
The Impact ◽  
Train System

One of the important methods for studying the valve train system is simulation. So the feasibility of valve motion simulation by Pro/E is discussed in this paper. After model establishing and connection completing, the valve motion is simulated and some results are reached. It can be seen from the results that valve motion can be simulated based on Pro/E environment. It also be seen that the valve acceleration varied at high frequency and the impact between the valve and seat is existed for the studied valve system. For studied valve it meets the demand of the engine

Evaluation of the impact of public investment programs on social and economic performance of territories

2019 ◽  
pp. 109-123
Author(s):  
I. E. Limonov ◽  
M. V. Nesena
Keyword(s):  
Bayesian Modeling ◽  
Positive Impact ◽  
Public Investment ◽  
Difference In Differences ◽  
The Public ◽  
Export Activity ◽  
Regional Investment ◽  
The Difference ◽  
The Impact ◽  
Development Institution

The purpose of this study is to evaluate the impact of public investment programs on the socio-economic development of territories. As a case, the federal target programs for the development of regions and investment programs of the financial development institution — Vnesheconombank, designed to solve the problems of regional development are considered. The impact of the public interventions were evaluated by the “difference in differences” method using Bayesian modeling. The results of the evaluation suggest the positive impact of federal target programs on the total factor productivity of regions and on innovation; and that regional investment programs of Vnesheconombank are improving the export activity. All of the investments considered are likely to have contributed to the reduction of unemployment, but their implementation has been accompanied by an increase in social inequality.

332-OR: Determining the Impact of Additional Macronutrients on the Glycemic-Insulin Dynamic Model

Diabetes ◽  
2019 ◽  
Vol 68 (Supplement 1) ◽  
pp. 332-OR
Author(s):  
BOYI JIANG ◽  
YUXIANG ZHONG ◽  
PRATIK AGRAWAL ◽  
TONI L. CORDERO ◽  
ROBERT VIGERSKY
Keyword(s):  
Dynamic Model ◽  
The Impact

The Use of Multimedia and its Impact on Bangladeshi EFL Learners at Tertiary Level

2020 ◽  
Vol 4 (2) ◽  
pp. 150
Author(s):  
Farzana Sharmin Pamela Islam
Keyword(s):  
Language Learning ◽  
Academic Writing ◽  
Teaching And Learning ◽  
English Language ◽  
Capital City ◽  
Tertiary Level ◽  
Language Classroom ◽  
The Difference ◽  
The Government ◽  
The Impact

As 21st century is the era of modern technologies with different aspects, it offers us to make the best use of them. After tape recorder and overhead projector (OHP), multimedia has become an important part of language classroom facilities for its unique and effective application in delivering and learning lesson. Although in many parts of Bangladesh, a South Asian developing country, where English enjoys the status of a foreign language, the use of multimedia in teaching and learning is viewed as a matter of luxury. However, nowadays the usefulness and the necessity of it are well recognized by the academics as well as the government. The study aims to focus on the difference between a traditional classroom void of multimedia and multimedia equipped classrooms at university level by explaining how multimedia support the students with enhanced opportunity to interact with diverse texts that give them more in-depth comprehension of the subject. It also focuses on audio-visual advantage of multimedia on the students’ English language learning. The study has followed a qualitative method to get an in-depth understanding of the impact of using multimedia in an English language classroom at tertiary level. For this purpose, the data have been collected from two different sources. Firstly, from students’ written response to  an open ended question as to their comparative experience of learning  lessons with and without multimedia facilities; and secondly, through  observation of English language classes at a private university of Dhaka, the capital city of Bangladesh. The discussion of the study is limited to  the use of multimedia in English language classroom using cartoons, images and music with a view to enhance students’ skills in academic writing, critical analysis of image and critical appreciation of music. For this purpose, cartoons in English language, images from Google and music from You Tube have got focused discussion in this paper.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

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