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Journal Article

Analysis of Friction Induced Stability, Bifurcation, Chaos, Stick-slip Vibration and their Impacts on Wiping Effect of Automotive Wiper System

2014-04-01
2014-01-0021
A 2 DOF nonlinear dynamic model of the automotive wiper system is established. Complex eigenvalues are calculated based on the complex modal theory, and the system stability as well as its dependence on wiping velocity is analyzed. Bifurcation characteristics of frictional self-excited vibration and stick-slip vibration relative to wiping velocity are studied through numerical analysis. Research of nonlinear vibration characteristics under various wiping velocities is conducted by means of phase trajectories, Poincaré map and frequency spectrum. The pervasive stick-slip vibration during wiping is confirmed, and its temporal and spatial distributions are analyzed by way of time history and contour map. Duty ratio of stick vibration and statistics of scraping residual are introduced as quantitative indexes for wiping effect evaluation. Results indicate that the negative slop of frictional-velocity characteristic is the root cause of system instability.
Technical Paper

System Evaluation Method for Two Planetary Gears Hybrid Powertrain under Gray Relational Analysis Based on Fuzzy AHP and Entropy Weight Method

2020-04-14
2020-01-0430
Millions of configurations of power-split hybrid powertrain can be generated due to variation in number of planetary-gear sets (PG), difference in number, type and installation location of shift actuators (clutches or brakes), and difference in connection positions of power components. Considering the large number of configurations, complex structures and control modes, it is vital to construct an appropriate multi-index system evaluation method, which directly affects the requirement fulfillment, the time and cost of 2-PG system configuration design. Considering one-sidedness (dynamics and economic performance), simplicity (linear combination of indicators) and subjectivity (relying on expert experience) of previous system evaluation method of 2-PG system design, a more systematic evaluation method is proposed in this paper. The proposed evaluation system consists of five aspects, involving dynamic, economy, comfort, reliability and cost, and more than 20 indexes.
Technical Paper

Analysis of Vibroacoustic Behaviors and Torque Ripple of SRMs with Different Phases and Poles

2020-04-14
2020-01-0467
In this study, the vibroacoustic characteristics and torque fluctuation of switched reluctance motors (SRMs) with different phases and poles have been analyzed in detail. Also, the common four SRMs, i.e., three-phase 6/4 SRM, four-phase 8/6 SRM, five-phase 10/8 SRM, and six-phase 12/10 SRM, have been selected. First, the spatial-temporal distribution characteristics of radial force in SRMs were revealed by virtue of the analytical derivation, which was validated by the 2D Fourier decomposition based on the finite-element results of radial force. Second, a multiphysics model, which was composed of an electromagnetic field, a mechanical field, and an acoustic field, was established to predict the noise behaviors of SRMs with different phases and poles. Third, the relationship between the torque fluctuation and the phases / poles of SRMs, and the relationship between the noise and the radial force / phases / poles are all analyzed.
Technical Paper

Study on EP Energy-Saving Vehicle

2008-06-23
2008-01-1775
The price of fossil fuels and the increasing inexorable energy crisis have become vital issues for everyone. Tongji University EconoPower Racing Team was established to participate in the “Honda EconoPower Cup” annually. Every contestant in the competition must finish a certain distance in the fixed time, with the gasoline supplied by the committee. After that the committee will measure the fuel consumption of every team and calculate the distance per liter fuel (the farther the better) to determine the champion. In order to enhance the EP vehicle's achievement we've made some improvements, such as framework, body, engine's optimization and so on. In this passage we mainly state some details of our research approaches in framework, steering, transmission, shape and driving strategy. The main technologies were: friction reduction, lightweight, enhancement of power train efficiency, tire selection and driving strategy.
Technical Paper

An Interactive Racing Car Driving Simulator Based on TCP/IP

2009-05-13
2009-01-1609
Real-time interaction between a driver and the simulator is problematic. In this study, the racing car driving simulator has been established, which is composed of the following functional components: Motion Controller, Simview, Scenario Editor, Application Programmer Interface (APIs) and Crash Simulation. With TCP/IP protocol, the Motion Controller receives driver's manipulation, road unevenness and crash situation of Simview, then generates motion streams that reflecting the current conditions, and sends them to Simview and to the hydraulic platform. Furthermore, by detecting and analyzing general vehicle two-dimensional impact, a kind of complete and applicable calculation method has been established, and complicated vehicle impacts can be analyzed accurately. This racecar driving simulator places a racing driver in a interactive environment, and provides the driver with high-fidelity motion, visual, auditory, and force feedback cues.
Technical Paper

Research on Effect of Wastegate Diameter on Turbocharged Gasoline Engine Perfor mance

2016-04-05
2016-01-1028
Boosting and downsizing is the trend of future gasoline engine technology. For the turbocharged engines, the actuation of intake boosting pressure is very important to the performance output. In this paper, a GT-Power simulation model is built based on a 1.5 L turbocharged gasoline engine as the research object. The accuracy of model has been verified through the bench test data. Then it is conducted with numerical simulation to analyze the effect of wastegate diameter on the engine performance, including power output and fuel economy. Mainly the wastegate diameter is optimized under full engine operating conditions. Finally an optimal MAP of wastegate diameter is drawn out through interpolation method. By the transmission relationship between wastegate and actuator, a wastegate control MAP for electric actuated wastegate can be obtained.
Technical Paper

Vehicle Stability Criterion Research Based on Phase Plane Method

2017-03-28
2017-01-1560
In this paper, a novel method is proposed to establish the vehicle yaw stability criterion based on the sideslip angle-yaw rate (β-r) phase plane method. First, nonlinear two degrees of freedom vehicle analysis model is established by adopting the Magic Formula of nonlinear tire model. Then, according to the model in the Matlab/Simulink environment, the β-r phase plane is gained. Emphatically, the effects of different driving conditions (front wheels steering angle, road adhesion coefficient and speed) on the stability boundaries of the phase plane are analyzed. Through a large number of simulation analysis, results show that there are two types of phase plane: curve stability region and diamond stability region, and the judgment method of the vehicle stability domain type under different driving conditions is solved.
Technical Paper

Analysis of Geographically Distributed Vehicle Powertrain System Validation Platform Based on X-in-the-Loop Theory

2017-03-28
2017-01-1674
X-in-the-loop (XiL) framework is a validation concept for vehicle product development, which integrates different virtual and physical components to improve the development efficiency. In order to develop and validate an extended validation method based on XiL, Tongji University in Shanghai, China and the Karlsruhe Institute of Technology (KIT) in Karlsruhe, Germany co- performed a feasibility study about an X-in-the-distance-loop demonstration platform. The X-in-the-distance-loop demonstration platform includes a MATLAB/Simulink software platform and geographically distributed equipment (driver simulator, driving electric motor and dynamometer test stand), which are used to conduct bidirectional experiments to test communication of powertrain data between China and Germany.
Technical Paper

Sound Quality Evaluation of Centralized Drive PMSM Based on Grade Scoring Method

2017-03-28
2017-01-1061
Electric vehicle driving permanent magnet synchronous motor has a wide speed range and load changes, with abundant harmonic currents, and its eccentric form is complex, which all result in poor sound quality and abnormal noise problems becoming increasingly prominent. To make a systematic and thorough study of the centralized drive permanent magnet synchronous motor (PMSM) is significant to ameliorate the sound quality and solve noise problems. MATLAB-based modeling technology, SPSS software, and the establishment of sound quality evaluation model for the centralized drive PMSM has a crucial reference value on the research and development of the electric vehicle driving permanent magnet synchronous motor. As for the sound quality of centralized drive PMSM, firstly, in order to get objective parameter values, evaluation models of objective parameters based on psychological acoustics should be established after the collection of the sound samples.
Technical Paper

Study on the Effect of Inverter Modulation Methods and Operating Condition on Common Mode EMI for Motor Drive System

2017-03-28
2017-01-1223
There are many electronic devices in electric vehicle (EV), making its electromagnetic compatibility (EMC) serious. Motor drive system is the main interference source of EV, whose electromagnetic interference (EMI) is much worse than conventional vehicle. In this paper, the motor drive system of EV was mainly researched, and a co-simulation method was proposed: control system and motor model were established with Matlab, and the equivalent circuit model of inverter and the cable model were established with Saber. By this way, a complete motor drive system model for conductive EMI was obtained. This modeling method can not only accurately establish the EMI sources and coupling paths, but can simulate the control strategy and operating conditions.
Technical Paper

Analysis under Vehicle-Pedalcyclist Risk Scenario Based on Comparison between Real Accident and Naturalistic Driving Data

2018-04-03
2018-01-1048
This paper constructs the Accident Crash Scenarios(ACSs) classification system based on the traffic accident data collected by the traffic management department in a Chinses city from 2013 to 2015. The classification system selects four influenced variables on the basis of Critical Driving Scenarios(CDSs) in Naturalistic Driving Data. The proportions of each variable are analyzed, and all ACSs are divided into 48 scenarios. The highest proportion of nine ACSs are extracted from all 10596 ACSs, and the result shows the ACSs involved Car-Pedalcyclist occupy the top four scenarios, and the scenarios involved intersection situations are worth attention. Pedalcyclists include bicyclists, motorcyclists, tri-cyclists and electric bicyclists. Multivariate Logistic Regression(MLR) analysis is then used to study the ACSs involved the type of Car-Pedalcyclist.
Technical Paper

Research into Autoignition Characteristics of Diesel Fuel in a Controllable Active Thermo-Atmosphere

2006-04-03
2006-01-0073
A novel method is applied to analysis the autoignition phenomenon. Experiments on the study of autoignition characteristics of diesel fuel were carried out with a Controllable Active Thermo-Atmosphere Combustor. The results show that the method for autoignition studying of liquid fuel is of feasibility. Autoignition delay time and autoignition height from the nozzle increase with the coflow temperature decreasing and autoignition delay time changes sensitively under lower coflow temperature. Liftoff height of diesel spray flame decreases with the increasing of coflow temperature. Lower temperature causes higher variance of liftoff height. It might be speculated that there are two different mechanisms of flame stabilization that the lower lift-off heights flames are related to a balance between the flow velocity and flame speed while the higher lift-off heights flames are stabilized by the mixture autoignition.
Technical Paper

Intelligent Cockpit Operation System: Indirect Rotary Transducer for an Automotive Screen Interface

2022-05-30
2022-01-5034
Indirect rotary transducer for an automotive screen interface is an innovative solution for the smart cockpit. The primary objective of this study is to design an indirect rotary transducer system, and study its feasibility in the smart cockpit. The working theory of this designed system is that the magnetic induction hall electronic chip can detect changes in the magnetic field. Several tests have been conducted, which show that the hypothesis of dangling operating system achieves the same effect as a hard-wired operating system. The results of the experiment indicate that the magnetic induction hall sensor can meet the specification of traditional hard-wired operating system. This system is a good concept for intelligent cab driving, which can fully meet the needs of the current market.
Technical Paper

Analysis of Discretization for Transient Impact Loads on Door Closing

2021-04-06
2021-01-0799
The transient impact load generated by door closing is used as the input of the closing condition, which is an important part of door system investigation. In this article, the basic theory of transfer path analysis (TPA) is introduced to handle the abnormal vibration of the front-left door with the glass down stall position of a certain vehicle during the closure. The transient impact loads are discretized under the closed door and obtained using the inverse matrix (IM) method in TPA. Vehicle test and bench test are conducted. The closed door is subjected to the transient impact loads of the sealing strip and the latch on the body side. In the vehicle test, acceleration sensors are pasted on the target point and the reference point on the door to obtain the acceleration vibration response upon the door closure.
Technical Paper

Investigation of PEM Fuel Cell Degradation Under On-Off Cyclic Condition

2021-12-31
2021-01-7022
Proton exchange membrane fuel cell (PEMFC) has attracted extensive attention in recent years because of its high efficiency and zero emission. Although fuel cell technology has made great progress, durability is still the bottleneck of its large-scale commercialization. In order to systematically study the degradation of fuel cell system for transportation applications, we selected the most severe operating condition - on-off cyclic condition as the research object, and focused on the influence of cell temperature and air relative humidity on the degradation rate of fuel cell by means of polarization curve, reference voltage and CV. The results show that with the same temperature, the fuel cell performance degradation rate first decreases and then increases with the decrease of humidity, which may be due to the increase of platinum ion transfer rate at high relative humidity and the dry membrane at low relative humidity.
Technical Paper

A Comparative Study on Energy Management Strategies for an Automotive Range-Extender Electric Powertrain

2021-12-31
2021-01-7027
In this work, the influences of various real-timely available energy management strategies on vehicle fuel consumption (VFC) and energy flow of a range-extender electric vehicle were studied The strategies include single-point, multi-point, speed-following, and equivalent consumption minimization strategy. In addition, the dynamic programming method which cannot be used in real time, but can provide the optimal solution for a known drive situation was used for comparison. VFCs and energy flow characteristics with different strategies under Worldwide Harmonized Light Vehicles Test Cycle (WLTC) were obtained through computer modeling, and the results were verified experimentally on a range-extender test bench. The experimental results are consistent with the modeled ones in general with a maximum deviation of 4.11%, which verifies the accuracy of the simulation models.
Technical Paper

Network Delay Modelling and Optimization of Internet-Based Distributed Test Platform for Fuel Cell Electric Vehicle Powertrain System

2021-12-15
2021-01-7026
The accelerated global progress in the research and development of automobile products, and the use of new technologies, such as the Internet, cloud computing and big data, to coordinate development platforms in different regions and fields, can reduce the duration and cost of development and testing. Specifically, in the context of the current coronavirus disease (COVID-19) pandemic, which has caused great obstacles to normal logistics and transportation, personnel exchanges and information communication, platforms that can support global operation are significant for product testing and validation, because they eliminate the need for the transportation of personnel and equipment. Therefore, the establishment of a distributed test and validation platform for automotive powertrain systems, which can integrate software and hardware testing, is important in terms of both scientific research and industrialization.
Technical Paper

Numerical Study of Gas Purge in Proton Exchange Membrane Fuel Cell

2021-12-31
2021-01-7005
A three-dimensional two-phase single-channel purge mode of proton exchange membrane fuel cell was established, and the steady-state and purge process were simulated. The water distribution in fuel cell after steady-state operation was studied. The changing trend of water content and water volume fraction under co-flow/counter-flow purge conditions was also studied. The results show that the membrane water content and water volume fraction under the ridge position of the fuel cell is more than the flow channel. The non-uniform distribution of membrane water along the direction of the flow channel is significant in co-flow, and the difference can be up to 6. In addition, the effects of different working conditions on purge were studied. It was found that in the purge condition, the water content of the inner membrane of 120s could be basically reduced to below 3.
Technical Paper

Path Planning Method for Perpendicular Parking Based on Vehicle Kinematics Model Using MPC Optimization

2022-03-29
2022-01-0085
In recent years, intelligent driving technology is being extensively studied. This paper proposes a path planning method for perpendicular parking based on vehicle kinematics model using MPC optimization, which aims to solve the perpendicular parking task. Firstly, in the case of any initial position and orientation of the vehicle, judging whether the vehicle can be parked at one step according to the location of the parking place and the width of the lane, and then calculating the starting position for parking, and use the Bezier curve to connect the initial position and the starting position. Secondly, reference parking path is calculated according to the collision constraints of the parking space. Finally, because the parking path based on the vehicle kinematics model is composed of circle arcs and straight lines, the curvature of the path is discontinuous. The reference parking path is optimized using Model Predictive Control (MPC).
Technical Paper

Parking Slots Allocation for Multiple Autonomous Valet Parking Vehicles

2022-03-29
2022-01-0148
Although autonomous valet parking technology can replace the driver to complete the parking operation, it is easy to cause traffic chaos in the case of lacking scheduling for multiple parking agents, especially when multiple cars compete for the same parking slot at the same time. Therefore, in order to ensure orderly traffic and parking safety, it is necessary to allocate parking slots reasonably for multiple autonomous valet parking vehicles. The parking slots allocation model is built as an optimal problem with constraints. Both parking mileage cost and parking difficult cost are considering at the objective function in the optimization problem. There are three types of constraints. The first is the capacity limit of a single parking slot, the second is the space limit occupied by a single vehicle, and the third is the total capacity limit of the parking lot. After establishing parking slots allocation model, the immune algorithm is coded to solve the problem.
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