Ride Comfort Values of Four Korean Cars in Highways

2005 ◽  
Author(s):  
Dong-Woon Park ◽  
Wan-Suk Yoo ◽  
Min-Seok Kim ◽  
Kyung-Tae Hong ◽  
Keum-Shik Hong
Keyword(s):  
Gasoline Engine ◽  
Ride Comfort ◽  
Weighting Function ◽  
Dynamic State ◽  
Seat Comfort ◽  
Power Spectral ◽  
Seat Cushion ◽  
Frequency Weighting ◽  
Air Cells ◽  
Utility Vehicle

Vibrations on the floor in a car are transmitted to the foot, hip, and back from the seat. Human body recognizes these vibrations, but the sensitivity for each vibration is different. To evaluate these vibrations, RMS(root mean square) of accelerations, VDV(vibration does value), percent vibration, and SEAT (Seat Effective Amplitude Transmissibility) value are commonly used. For the SEAT value calculation, the PSD (Power Spectral Density) of the accelerations at the seat and the PSD of the floor are used with the frequency weighting function. If the SEAT value is less than 1, the vibration level on the seat is less than the floor, which means seat is effective to reduce the vibration. In this paper, four types of cars, i.e., a small size car of 1300cc gasoline engine, a mid-size car of 1800 gasoline engine, a full-size luxurious car of 3600cc gasoline engine, and a SUV (sport utility vehicle) of 2900 diesel engine are used and compared ride comforts using SEAT values. Experiments were carried on a highway near the suburb of Busan metro-politan city in South Korea. To compare ride comforts, the SEAT values in dynamic state are compared. Several air cells are installed in the seat cushion to improve seat comfort and to adjust seat properties by changing the air pressure. From the real car experiments, optimum air cell pressure depending on the vehicle speeds and road conditions are recommended.

Enhancement of Ride Comfort Adjusting Seat Stiffness With Air-Cells

2008 ◽  
Author(s):  
Wan-Suk Yoo ◽  
Dong W. Park ◽  
Min S. Kim ◽  
Geum S. Hong
Keyword(s):  
Computer Simulation ◽  
Ride Comfort ◽  
Physical Experiment ◽  
Air Pressure ◽  
Weighting Functions ◽  
Passenger Car ◽  
Seat Cushion ◽  
Acceleration Data ◽  
Air Cells

In this paper, the ride comfort obtained from computer simulation was compared to that of physical experiment. To measure ride comfort of a passenger car, acceleration data was obtained from the floor and seat during highway running with different speeds. The measured acceleration components were multiplied by weighting functions, and then summed together to calculate overall ride values. For the computer simulation, MADYMO software was employed. To enhance ride comfort, several air cells are installed in the seat cushion to adjust the stiffness of seat by changing the air pressure in the cells. For the ride comforts, SEAT (Seat Effective Amplitude Transmissibility) was compared. To choose optimum air pressure in the cell, several test drivers with different weights were tested on several vehicle speeds.

Nonlinear Vibration and Comfort Analysis of High-Speed Trains Moving Over Railway Bridges

Volume 2 ◽  
2004 ◽  
Author(s):  
M. H. Kargarnovin ◽  
D. Younesian ◽  
D. J. Thompson ◽  
C. J. C. Jones
Keyword(s):  
High Speed ◽  
Ride Comfort ◽  
Beam Theory ◽  
Maximum Acceleration ◽  
Railway Bridges ◽  
Comfort Index ◽  
Power Spectral ◽  
High Speed Trains ◽  
Train Speed ◽  
Track Bridge

The ride comfort of high-speed trains passing over railway bridges is studied in this paper. The effects of some nonlinear parameters in a carriage-track-bridge system are investigated such as the load-stiffening characteristics of the rail-pad and the ballast, rubber elements in the primary and secondary suspensions systems. The influence of the track irregularity and train speed on two comfort indicators, namely Sperling’s comfort index and the maximum acceleration level, are also studied. Timoshenko beam theory is used for modelling the rail and bridge and two layers of parallel damped springs in conjunction with a layer of mass are used to model the rail-pads, sleepers and ballast. A randomly irregular vertical track profile is modelled, characterised by a power spectral density (PSD). The ‘roughness’ is generated for three classes of tracks. Nonlinear Hertz theory is used for modelling the wheel-rail contact.

scholarly journals Effect of the Anti-Yaw Damper on Carbody Vertical Vibration and Ride Comfort of Railway Vehicle

2020 ◽  
Vol 10 (22) ◽  
pp. 8167
Author(s):  
Mădălina Dumitriu ◽  
Dragoș Ionuț Stănică
Keyword(s):  
Ride Comfort ◽  
Vertical Vibration ◽  
Theoretical Research ◽  
Railway Vehicle ◽  
Vertical Acceleration ◽  
Damping Force ◽  
Comfort Index ◽  
Lateral Vibrations ◽  
Power Spectral ◽  
Vertical Vibrations

The theoretical research on means to reduce the vertical vibrations and improve the ride comfort of the railway vehicle relies on a mechanical model obtained from the simplified representation of the vehicle, while considering the important factors and elements affecting the vibration behaviour of the carbody. One of these elements is the anti-yaw damper, mounted longitudinally, between the bogie and the vehicle carbody. The anti-yaw damper reduces the lateral vibrations and inhibits the yaw motion of the vehicle, a reason for which this element is not usually introduced in the vehicle model when studying the vertical vibrations. Nevertheless, due to the position of the clamping points of the anti-yaw damper onto the carbody and the bogie, the damping force is generated not only in the yawing direction but also in the vertical and longitudinal directions. These forces act upon the vehicle carbody, impacting its vertical vibration behaviour. The paper analyzes the effect of the anti-winding damper on the vertical vibrations of the railway vehicle carbody and the ride comfort, based on the results derived from the numerical simulations. They highlight the influence of the damping, stiffness and the damper mounting angle on the power spectral density of the carbody vertical acceleration and the ride comfort index.

Simulation of Bus Ride Comfort under the Excitation of Road Irregularity

2012 ◽  
Vol 510 ◽  
pp. 249-254 ◽  
Author(s):  
Jin Feng ◽  
Yuan Hua Chen
Keyword(s):  
Finite Element ◽  
Modal Analysis ◽  
Ride Comfort ◽  
Temporal Frequency ◽  
Vertical Vibration ◽  
Fe Model ◽  
Analysis Method ◽  
The Road ◽  
Power Spectral ◽  
Bus Structure

Bus vibration is studied by the finite element method (FEM) base on bus structure model. The bus mathematical model of vertical vibration is established and the vibration response variables were deduced with the modal analysis method. The finite element (FE) model is established and decoupled. The transformational relation between spatial frequency displacement power spectral density (PSD) and temporal frequency displacement PSD and the sampling characteristics of the road irregularity PSD in numerical computation are discussed. Road irregularity load is modeled in software. The FE model is solved using modal analysis method and the acceleration PSD of each keypoint can be gained. Finally, a road test experiment is carried on to verify the simulation results. The example indicated that study on vehicle ride comford by FEM has instructive meaning.

Control of Maglev Suspension Systems

1996 ◽  
Vol 2 (3) ◽  
pp. 349-368 ◽  
Author(s):  
Y. Cai ◽  
S.S. Chen
Keyword(s):  
Degrees Of Freedom ◽  
Ride Comfort ◽  
Vehicle Suspension ◽  
Semiactive Control ◽  
One Dimensional ◽  
Suspension Systems ◽  
Maglev Vehicle ◽  
Power Spectral ◽  
Power Spectral Densities ◽  
Control Designs

This study investigates alternate designs for control of maglev vehicle suspension systems. Active and semiactive control-law designs are introduced into primary and secondary suspensions of maglev vehi cles. A one-dimensional vehicle with two degrees of freedom, simulating the German Transrapid Magiev System, is used. The transient and frequency responses of suspension systems and power spectral densities of vehicle accelerations are calculated to evaluate different control designs. The results show that both active and semiactive control designs improve vehicle response and provide acceptable ride comfort for maglev systems.

scholarly journals Simulation of Pavement Random Excitation Based on Harmonic Superposition Method

2021 ◽  
Vol 2 (3) ◽  
Author(s):  
Kehui Ma ◽  
Yongguo Zhang ◽  
Xü Zhen
Keyword(s):  
Spectral Density ◽  
Power Spectral Density ◽  
Ride Comfort ◽  
Random Excitation ◽  
Superposition Method ◽  
Generation Model ◽  
The Road ◽  
Power Spectral ◽  
Control Research ◽  
The Relationship

The road input model is very important in the analysis of vehicle ride comfort and handling stability. Based on the analysis of the relationship between the spatial frequency power spectral density and the time power spectral density of the road, the road signal generation model is established. The simulation is carried out under different vehicle speeds, and the B and C-level random road time excitation signals are generated. The power spectral density is used to compare the simulation results of the model with the road classification standard. The experimental results show that the results are accurate and can provide reliable excitation signals for vehicle control research.

Ride Comfort of Five-Axle Tractor/Semi-Trailer

2000 ◽  
Author(s):  
Zhenyu Jiang ◽  
Moustafa El-Gindy ◽  
Donald Streit
Keyword(s):  
Ride Comfort ◽  
General Concept ◽  
Ride Quality ◽  
Vertical Acceleration ◽  
Gaussian Random Process ◽  
Long Distance ◽  
Power Spectral ◽  
Road Profile ◽  
Computer Based ◽  
Simulation Results

Abstract The issue of ride comfort for vehicle operations has recently generated considerable interest especially in heavy vehicle systems since long-distance drivers are more likely to experience high levels of vibration. This paper introduces the general concept of vibration-related health problems, discusses ride comfort assessment criteria and methods, and then focuses on the methodology of using computer simulation to analyze ride comfort. The computer-based ride comfort model can be divided into three sub-models: vehicle model, driver/seat model, and road profile input model. Several vehicle models and driver/seat models are reviewed and detailed modeling techniques are introduced. A five-axle tractor/semi-trailer/driver combination ride comfort simulation model is developed in this paper using the software DADS. Both four-spring tandem suspension and independent air spring suspension are studied. Road profiles are assumed as static zero mean Gaussian random process. Vertical acceleration at the interface between seat and driver body is obtained from simulation results. Power spectral density and root mean square (RMS) vertical acceleration are calculated based on simulation results. RMS acceleration at ISO classified good and average roads are compared with ISO 8-hour fatigue vibration limit. It is found that RMS acceleration of this particular vehicle simulated in this paper is below the ISO 8-hour fatigue limit for both good and average roads when traveling at the speed of fifty miles per hour. This implies a good ride comfort. Axle dynamic load coefficients (DLC) are calculated for four suspension configurations that are combinations of air springs and steel springs. Results show that large DLC doesn’t necessarily indicate bad ride quality.

Analysis of Vibration Characteristics of Transport Utility Vehicle by Finite Element Method

2019 ◽  
Vol 11 (1) ◽  
Author(s):  
Vikas Radhakrishna Deulgaonkar
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Dynamic Behaviour ◽  
Ride Comfort ◽  
Vibration Characteristics ◽  
Surface Model ◽  
Element Analysis ◽  
Track Width ◽  
Vehicle Structure ◽  
Utility Vehicle

Present work deals with the design and analysis vibration characteristics for transport utility vehicle. The transport utility vehicle is designed using automotive industry standards. The dynamic behaviour of vehicle depends on the selection of overall dimensions, wheel base, track width, overall height and width that are decided using central motor vehicle rules. The selected dimensions for vertical and horizontal pillar members of the transport bus are modified to enhance the strength, stiffness and stability of the superstructure during travel. This increased stability enhances the ride comfort and passenger safety. Analysing the effect of utilizing manual meshing in complex areas of a transport utility vehicle for vibration analysis and passenger ride comfort has also been carried out. Modal analysis to evaluate the dynamic behaviour of transport utility vehicle model is also carried. Further with the use of finite element analysis deflection vehicle structure is evaluated. The outcomes from the analysis are compared with the behaviour of chassis mounted platform in dynamic conditions and are found in close correlation. The vehicle structure behaves as a single entity in dynamic situations, so surface model is prepared. Element selection for the finite element analysis is carried by considering plane stress condition. Two-dimensional quadrilateral shell elements are extensively used for meshing of the computer model of the vehicle structure. Complex areas in the optimised vehicle structure are meshed using relevant combination of quads and trias. The values of vector sum displacement and frequencies are found to be in good agreement with the experimental ones.

The On-Road Exhaust Emissions from Vehicles Fitted with the Start-Stop System

2013 ◽  
Vol 390 ◽  
pp. 343-349 ◽  
Author(s):  
Jerzy Merkisz ◽  
Pawel Fuc ◽  
Piotr Lijewski ◽  
Andrzej Ziolkowski
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Measurement System ◽  
Power Output ◽  
Gasoline Engine ◽  
Exhaust Emissions ◽  
The Other ◽  
Exhaust Emission ◽  
Traffic Conditions ◽  
Utility Vehicle

The paper describes the influence of the start-stop system on the exhaust emissions and fuel consumption. The tests were performed for two vehicles. The first one was a vehicle designed specifically to operate in city conditions. It was fitted with a gasoline engine of the displacement of 0.9 dm3 and maximum power output of 63.7 kW. The other vehicle was an SUV (Sports Utility Vehicle) fitted with a diesel engine of the displacement of 3.0 dm3. The measurements of the exhaust emission were carried out on the same route under actual traffic conditions. For the tests a portable exhaust emissions analyzer from the PEMS group SEMTECH DS was used (PEMS Portable Emissions Measurement System).

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