Technical Paper collections have been re-named for better clarity and alignment.x

Your Selections

Tongji University
Show Only

Collections

File Formats

Content Types

Dates

Sectors

Topics

Authors

Publishers

Affiliations

Events

   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Drivable area detection and vehicle location based on multi-sensor information fusion

Tongji University-Jie Bai, Sen Li, Jinzhu Wang, Libo Huang, Lianfei Dong
Suzhou Haomibo Technology Co. Ltd.-Panpan Tong
  • Technical Paper
  • 2020-01-1027
To be published on 2020-04-14 by SAE International in United States
Multi-sensor information fusion framework is the eyes for unmanned driving and Advanced Driver Assistance System (ADAS) to perceive the surrounding environment. In addition to the perception of the surrounding environment, real-time vehicle location is also the key and difficult point of unmanned driving technology. The disappearance of high-precision GPS differential signal and the defect of lane line will bring much more difficult for vehicle self-locating. In this paper, a road boundary feature extraction algorithm is proposed based on multi-sensor information fusion of automotive radar and vision to realize the auxiliary locating of vehicles. Firstly, we designed a 79GHz (78-81GHz) Ultra Wide Band(UWB)millimeter wave radar, which can obtain the point cloud information of road edge features such as guardrail or green belt and so on. Secondly, the pixel semantic information of the drivable area of road can be obtained by the pixel semantic segmentation of image information through deep learning. Then, the road boundary equation in vehicle coordinate system is obtained by clustering and fusion of the road boundary point cloud information and the boundary semantic…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

A progress review on cold start methods and influence factors for automotive PEMFC system

Tongji University-Pengcheng Liu
Tongji Univ-Sichuan Xu
  • Technical Paper
  • 2020-01-0852
To be published on 2020-04-14 by SAE International in United States
This review presents comprehensive methods and influence factors of the research progress in solving the Proton Exchange Membrane Fuel Cells(PEMFC) system cold start problems with more than 100 patents, papers and reports. This may do some help for PEMFC system cold start from the point of practical utilization. This paper can be divided into six parts. Firstly, in introduction part, the recent achievements and goals will be summarized. Then, thanks to the cold start whole process includes PEMFC system shut down and cold start from subfreezing environment, so different actions or methods will be discussed based on system shutdown and cold start from subfreezing environment. Solutions and methods for fuel cell system shutdown are summarized into two categories: purge solution and keeping warm. In regard to the strategies for PEMFC system cold startup, different heating solutions are classified into self-heating strategies and auxiliary-heating heating depending on their heating sources. Solutions and strategies are compared and concluded based on the recent progress. Moreover, the whole process strategies will be concluded according to the relative researches. What’s…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Simulation Analysis of Early and Late Miller Cycle Strategies Influence on the Working Process of Diesel Engine

Tongji University-Zhiwei Feng
Jining Polytechnic-Xiuyuan Li
  • Technical Paper
  • 2020-01-0662
To be published on 2020-04-14 by SAE International in United States
Based on the working model of a diesel engine, the influence of 2 Miller cycle strategies-Early Intake Valve Closure (EIVC) and Late Intake Valve Closure (LIVC) on the combustion and emissions of diesel engine was analyzed, then the working condition of each Miller cycle strategies on the engine under the rated speed was optimized through the adjust of the valve timing, boost pressure and the injection timing. The research found that both delaying and advancing the closure timing of the intake valve can decrease the pressure and temperature during compression stroke, prolonging the ignition delay. However, due to the decrease of the working media inside the cylinder, the average in-cylinder temperature and soot emissions will increase, which can be alleviated by raising the boost pressure and the resulting compensation of the intake loss. The study found that together with increasing boost pressure and delaying injection timing, both EIVC and LIVC can reduce the NOx and soot emissions simultaneously. The simulation results show that while keeping the peak firing pressure the same as the original machine,…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Characteristics of Auto-ignition for Lubricants and Lubricant/Gasoline based on An Innovative Single Droplet Combustion System

Tongji University-Kaifeng Pan, Jun Deng, Zongjie Hu, Wei Xie
Tongji Univ-Zhijun Wu, Liguang Li
  • Technical Paper
  • 2020-01-1428
To be published on 2020-04-14 by SAE International in United States
Due to the advantages of low weight, low emission and good fuel economy, downsized turbocharged gasoline direct injection (GDI) engines are widely-applied nowadays. However, Low-Speed Pre-Ignition (LSPI) phenomenon observed in these engines restricts their improvement of performance. Some researchers have shown that auto-ignition of lubricant in the combustion chamber has a great effect on the LSPI frequency. To study the auto-ignition characteristics of lubricant, an innovative single droplet auto-ignition measurement system for lubricant and its mixture is designed and developed, with better accuracy and effectiveness. The experiments are carried out by hanging lubricant droplets on the thermocouple node under active thermo-atmosphere provided by a small Dibble burner. The auto-ignition process of lubricant droplets is recorded by a high-speed camera. Influences of different base oil types, viscosities, calcium contents, initial droplet diameters, co-flow speeds, new oil, used oil and blending ratios of lubricant and gasoline on the ignition delay time of droplets are investigated at different droplet temperatures. The co-flow field temperature varies from 823K to 1323K. Equivalent diameters of droplets, 0.99mm, 1.24mm and 1.63mm, generated…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Nonlinear Model Predictive Control of Autonomous Vehicles Considering Dynamic Stability Constraints

Tongji University-Xunjie Chen, Guangqiang Wu, Meng Ren
  • Technical Paper
  • 2020-01-1400
To be published on 2020-04-14 by SAE International in United States
The autonomous vehicle performance is increasingly highlighted in many highway driving scenarios, which leads to more priorities to vehicle stability as well as tracking accuracy. In this paper, a nonlinear model predictive controller for autonomous vehicle trajectory tracking is designed and verified through a real-time driving simulator of a virtual test track. The dynamic stability constraints of nonlinear model predictive control (NLMPC) are obtained by a novel quadrilateral stability region criterion instead of the conventional phase plane method using the double-line region. First, a typical lane change scene of overtaking is selected and a new composited trajectory model is proposed as a reference path that combines smoothness of sine wave and comfort of linear functional path. Reference lateral velocity, azimuth angle, yaw rate, and front wheel steering angle are subsequently taken into account. Then, by establishing a nonlinear vehicle dynamics model where Magic Formula of nonlinear tire model is adapted, the quadrilateral vehicle stability region is defined in consideration of designed velocity, road adhesion coefficient, and front wheel steering angle. Working condition-variant constraints determined by…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Simulation and Parametric Analysis of Battery Thermal Management System Using Phase Change Material

Tongji University-Zhao Li, Sichuan Xu
CATARC-Chunjing Lin, Yuhan Sun
  • Technical Paper
  • 2020-01-0866
To be published on 2020-04-14 by SAE International in United States
The thermophysical parameters and amount of composite phase change materials (PCMs) have a decisive influence on the thermal control effects of thermal management systems (TMSs). At the same time, the various thermophysical parameters of the composite PCM are interrelated. For example, increasing the thermal conductivity is bound to mean a decrease in the latent heat of phase change, so a balance needs to be achieved between these parameters. In this paper, a prismatic LiFePO4 battery cell cooled by composite PCM is comprehensively analyzed by changing the phase change temperature, thermal conductivity and amount of composite PCM. The influence of the composite PCM parameters on the cooling and temperature homogenization effect of the TMS is analyzed. which can give useful guide to the preparation of composite PCMs and design of the heat transfer enhancement methods for TMSs.
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Joint Calibration of Dual LiDARs and Camera using a Circular Chessboard

Tongji University-Zhenwen deng, Lu Xiong, Dong Yin, Fengwu Shan
  • Technical Paper
  • 2020-01-0098
To be published on 2020-04-14 by SAE International in United States
Environment perception is a crucial subsystem in autonomous vehicles. In order to build safety and efficient traffic transportation, several researches have been proposed to build accurate, robust and real-time perception systems. Camera and LiDAR are widely mounted on self-driving cars and developed with many algorithms in recent years. The fusion system of camera and LiDAR provides state-of the-art methods for environmental perception due to the defects of single vehicular sensor. Extrinsic parameter calibration is able to align the coordinate systems of sensors and has been drawing enormous attention. However, differ from spatial alignment of two sensors’ data, joint calibration of multi-sensors (more than three devices) should balance the degree of alignment between each one. In this paper, we assemble a test platform which is made up of dual LiDARs and monocular camera and is the same as the sensing hardware architecture of intelligent sweeper designed by our laboratory. Meanwhile, we propose the related joint calibration method using a circular chessboard. The center of circular chessboard is respectively detected in camera image to get pixel coordinates…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Effect of Hydrous Ethanol Combined with EGR on Performance of GDI Engine

Tongji University-Yifei Duan, Xiuyong Shi, Yang Kang, Yansu Liao, Lishuang Duan
  • Technical Paper
  • 2020-01-0348
To be published on 2020-04-14 by SAE International in United States
In recent years, PM emission from GDI engines has been gradually paid attention to, while the hydrous ethanol has a high oxygen content and a fast burning rate, which can effectively improve the combustion environment. In addition, EGR can effectively reduce engine NOx emissions, and combining EGR technology with GDI engines is becoming a new research direction. In this paper, the effects of hydrous ethanol gasoline on the combustion and emission characteristics of direct injection engines are analyzed through direct injection engine bench test. The results show that the increase of the proportion of hydrous ethanol accelerates the combustion rate, shortens the combustion duration, and peaks the cylinder pressure and heat release rate. At the same time, the combustion efficiency is improved. The hydrous ethanol gasoline can effectively improve the gaseous and PM emissions of the direct injection engine. The concentration of CO, HC and the amount of PM is significantly reduced, and the particle size of the particles is transferred from the accumulation state to the nuclear state. Furthermore, a one-dimensional simulation model was…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Development and Demonstration of a New Range-Extension Hybrid Powertrain Concept

Tongji University-Zhiyu Han, Zhenkuo Wu, Xiaojie Gao, Yongzheng Sun, Runyu Ni, Jian Feng, Jian zhong, Xinbo Chen, Zhiguo Zhao, Zhuoping Yu
  • Technical Paper
  • 2020-01-0845
To be published on 2020-04-14 by SAE International in United States
A new range-extension hybrid powertrain concept, namely the Tongji Extended-range Hybrid Technology (TJEHT) was developed and demonstrated in this study. This hybrid system is composed of a direct-injection gasoline engine, a traction motor, an integrated starter-generator (ISG) motor, and a transmission. In addition, an electronically controlled clutch between the ISG motor and engine, and an electronically controlled synchronizer between the ISG motor and transmission are also employed in the transmission case. Hence, this system can provide six basic operating modes including the single-motor driving, dual-motor driving, serial driving, parallel driving, engine-only driving and regeneration mode depending on the engagement status of the clutch and synchronizer. Importantly, the unique dual-motor operation mode can improve vehicle acceleration performance and the overall operating efficiency. The hybrid system controls and energy management strategy based on equivalent fuel consumption minimization were developed and validated. The choice of an operating mode is optimized according to the drivers’ demand, actual vehicle state, operation conditions, and other boundary conditions. In this paper, the powertrain architecture and operating modes are firstly described. Secondly, the…
   This content is not included in your SAE MOBILUS subscription, or you are not logged in.

Experimental performance Analysis of Multi-Channel Active Control System for Road Noise in Vehicles Using FXLMS algorithm

Tongji University-Xiongfei Pi
Tongji Univ-Lijun Zhang, Dejian Meng
  • Technical Paper
  • 2020-01-1277
To be published on 2020-04-14 by SAE International in United States
It’s significant to analyze the Experimental performance of active control system for road noise. In this paper, a 4-channel active control system of vehicle road noise based on FXLMS algorithm is established. The bench test and road test are carried out to test and analyze the performance of the control system. Firstly, the general mathematic model of the multi-channel active control system based on FXLMS algorithm is established. The computational complexity of the algorithm is analyzed and compared with that of the adaptive notch filter. Secondly, a hardware-in-the-loop test bench based on multi-channel FXLMS algorithm and a measurement system based on DASP are set up, to measure the noise reduction performance of active noise control system under various working conditions. Finally, using four speakers, four Accelerometers and two microphones, the bench test and the road test are carried out under various working conditions and the results are analyzed.