• International Journal of Automotive Technology
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• v.8 no.6
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• pp.731-744
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• 2007

A method for dynamic analysis and design calculation of a Powertrain Mounting System(PMS) including Hydraulic Engine Mounts(HEM) is developed with the aim of controlling powertrain motion and reducing low-frequency vibration in pitch and bounce modes. Here the pitch mode of the powertrain is defined as the mode rotating around the crankshaft of an engine for a transversely mounted powertrain. The powertrain is modeled as a rigid body connected to rigid ground by rubber mounts and/or HEMs. A mount is simplified as a three-dimensional spring with damping elements in its Local Coordinate System(LCS). The relation between force and displacement of each mount in its LCS is usually nonlinear and is simplified as piecewise linear in five ranges in this paper. An equation for estimating displacements of the powertrain center of gravity(C.G.) under static or quasi-static load is developed using Newton's second law, and an iterative algorithm is presented to calculate the displacements. Also an equation for analyzing the dynamic response of the powertrain under ground and engine shake excitations is derived using Newton's second law. Formulae for calculating reaction forces and displacements at each mount are presented. A generic PMS with four rubber mounts or two rubber mounts and two HEMs are used to validate the dynamic analysis and design calculation methods. Calculated displacements of the powertrain C.G. under static or quasi-static loads show that a powertrain motion can meet the displacement limits by properly selecting the stiffness and coordinates of the tuning points of each mount in its LCS using the calculation methods developed in this paper. Simulation results of the dynamic responses of a powertrain C.G. and the reaction forces at mounts demonstrate that resonance peaks can be reduced effectively with HEMs designed on the basis of the proposed methods.

• Journal of Power System Engineering
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• v.12 no.2
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• pp.23-28
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• 2008

The primary objective of this study is to truly understand reaction force be due to engine exciting force. Exciting forces of the engine apply a source of the vehicle NVH(Noise, Vibration, Harshness). To understand reaction force was applied MSC.Nastran software. Analyzed frequency response analysis of powertrain mount system. First, engine exciting force was applied field function. Also nonlinear characteristics was applied field function : such as dynamic spring constant and loss factor. And nonlinear characteristics was applied CBUSH. Generally characteristics of rubber mount is constant frequency. But characteristics of hydraulic mount depend to frequency. Therefore nonlinear characteristics was applied. Powertrain mounting system be influenced by powertrain specification, mount position, mount angle and mount characteristics etc. In this study, we was analyzed effects of powertrain mounting system. And we was varied dynamics spring constant and loss factor of mounts.

• Journal of Drive and Control
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• v.11 no.2
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• pp.22-29
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• 2014

This paper presents simulation-based analysis of energy flow of a wheel loader. The objective of this study is to analyze the energy flow of a wheel loader during driving and working. Because the wheel loader powertrain consists of a mechanical and hydraulic powertrain, the generated power from the engine is divided into 2 powertrains. Further, a virtual prediction of energy flow in the powertrains is a key factor in terms of optimal design. Accordingly, the simulation model that is able to predict the virtual energy flow is developed and analyzed in this study. The proposed wheel loader simulation model has been constructed in the Matlab/Simulink environment. It is expected that the developed simulation model will analyze the energy flow and efficiency in the design stage.

• Transactions of the Korean Society of Automotive Engineers
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• v.17 no.2
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• pp.165-170
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• 2009

Pressure ripple, vibration and noise level are measured in each parts of the power steering system. MD(Mahalanobis Distance) is calculated by using MTS(Mahalanobis Taguchi System) with measured data, and noise sensitive components are selected. The components applied detail design parameters are made and data is measured. After that MD is calculated also. Mean value and SN ratio can be obtained from the MD. Effective noise reduction technique and dominant design parameters in hydraulic power steering system are introduced.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.37 no.5
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• pp.601-607
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• 2013

This paper presents the development and validation of a wheel loader simulation model. The objective of doing so is to evaluate the performance of the wheel loader and improve its overall performance using Matlab/Simulink. The wheel loader simulation model consists of 4 parts: mechanical/hydraulic powertrain model and vehicle/working dynamic model. An integrated simulation model is required to evaluate and improve the performance of the wheel loader. It is expected that this model will be applied to fuel economizing, improving the pace of operation by using the hybrid system, and the intelligent wheel loader. The performance of the proposed simulation model has been validated by using Matlab/Simulink to compare the driving and the working experimental data.

• Transactions of The Korea Fluid Power Systems Society
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• v.5 no.4
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• pp.1-9
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• 2008

In this paper, an energy regeneration algorithm is proposed to make the maximum use of the regenerative braking energy for a parallel hybrid electric vehicle(HEV) equipped with a continuous variable transmission(CVT). The regenerative algorithm is developed by considering the battery state of charge(SOC), vehicle velocity and motor capacity. The hydraulic module consists of a reducing valve and a power unit to supply the front wheel brake pressure according to the control algorithm. In order to evaluate the performance of the regenerative braking algorithm and the hydraulic module, a hardware-in-the-loop simulation (HILS) is performed. In the HILS system, the brake system consists of four wheel brakes and the hydraulic module. Dynamic characteristics of the HEV are simulated using an HEV simulator. In the HEV simulator, each element of the HEV powertrain such as internal combustion engine, motor, battery and CVT is modelled using MATLAB/$Simulink^{(R)}$. In the HILS, a driver operates the brake pedal with his or her foot while the vehicle speed is displayed on the monitor in real time. It is found from the HILS that the regenerative braking algorithm and the hydraulic module suggested in this paper provide a satisfactory braking performance in tracking the driving schedule and maintaining the battery state of charge.

• Journal of Mechanical Science and Technology
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• v.16 no.7
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• pp.882-888
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• 2002

In this paper, an algorithm to increase the shift speed is suggested by increasing the line pressure for a metal belt CVT. In order to control the shift speed, an algorithm to calculate the target shift speed is presented from the modified CVT shift dynamics. In applying the shift speed control algorithm, a criterion is proposed to prevent the excessive hydraulic loss due to the increased line pressure. Simulations are performed based on the dynamic models of the hydraulic control valves, powertrain and the vehicle. It is found from the simulation results that performance of the engine operation can be improved by the faster shift speed, which results in the improved fuel economy by 2% compared with that of the conventional electronic control CVT in spite of the increased hydraulic loss due to the increased line pressure.

• Transactions of the Korean Society of Automotive Engineers
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• v.8 no.4
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• pp.68-84
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• 2000

A study to reduce the transient torque in shifting in automatic transmission has been very important issue. Recently it is really dominant to decrease the torque by using independent-acting hydraulic circuit because we can control the clutch pressure actively and elaborately. So we design the new hydraulic circuit to control the clutches in automatic transmission and make the module library of computer simulations, We apply the results to GM model automatic transmission and carry out 1longrightarrow4 shifting simulations. By this work we recognize the capability of active and elaborate clutch pressure control using new hydraulic circuit. In addition We develop the tool to simulate the powertrain system. It is easier to update and exchange the subsystem model or parameters than conventional simulation tools.

• Journal of Mechanical Science and Technology
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• v.15 no.11
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• pp.1490-1498
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• 2001

In this paper, a regenerative braking algorithm is presented and performance of a hybrid electric vehicle (HEV) is investigated. The regenerative braking algorithm calculates the available regenera tive braking torque by considering the motor characteristics, the battery SOC and the CVT speed ratio. When the regenerative braking and the friction braking are applied simultaneously, the friction braking torque corresponding to the regenerative braking should be reduced by decreasing the hydraulic pressure at the front wheel. To implement the regenerative braking algorithm, a hydraulic braking module is designed. In addition, the HEV powertrain models including the internal combustion engine, electric motor, battery, CVT and the regenerative braking system are obtained using AMESim, and the regenerative braking performance is investigated by the simulation. Simulation results show that the proposed regenerative braking algorithm contributes to increasing the battery SOC which results in the improved fuel economy. To verify the regenerative braking algorithm, an experimental study is performed. It is found from the experimental results that the regenerative braking hydraulic module developed in this study generates the desired front wheel hydraulic pressure specified by the regenerative braking control algorithm.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.5
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• pp.12-18
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• 2004

Transient natures of diesel sprays are often characterized with spray visualization, since it is a non-intrusive and straightforward technique to be applied. However, as injection pressure is increased higher than a thousand bar in a modern direct injection diesel engine, very fine temporal and spatial resolutions in the spray visualization are required while sprays become optically denser. Discussed in this paper are macroscopic and microscopic spray visualization techniques and an example of image processing process for efficient and consistent measurement of spray parameters. The injection rate measurement method based on hydraulic pulse principle was suggested as a way of estimating injection velocity for transient diesel sprays. The spray visualization and injection rate measurement techniques were applied to analyze transient diesel sprays from a common-rail injection system and found to be practically effective.