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During the launch of a car, severe torsional vibration sometimes may occur in its driveline due to somewhat the slipping of the clutch, its intuitive sense for an occupant is the longitudinal vibration of the vehicle, referred to as the launch shudder whose characteristic frequency is from 5 to 25 Hz generally. As the main vibration sources of the driveline and its crucial nonlinear components, the variable stiffness and backlash of the gear meshing are considered, their impacts on the launch shudder are analyzed in this paper. Conformal mapping, finite element method and regression method etc. are the main approaches to calculate the variable meshing stiffness of a gear pair. If this stiffness is get, it can usually be substituted for its approximate analytical expression, just with finite harmonic terms, in Fourier Series form into Ordinary Differential Equations(ODEs) to calculate the vehicle responses with its nonlinearity considered.

Turbochargers improve performance in internal combustion engines. Due to low production costs, TC assemblies are supported on floating ring bearings. In current lubrication analysis of floating ring bearing, inner and outer oil film are usually supposed to be adiabatic. The heat generated by frictional power is carried out by the lubricant flow. In reality, under real operating conditions, there existed heat transfer between the inner and outer film. In this paper, the lubrication performance of floating ring bearing when considering heat transfer between inner film and outer film is studied. The lubrication model of the floating ring is established and the heat transferred through the ring between the inner and outer film is calculated. The calculation results show that heat flow between the inner and outer film under different outer film eccentricity ratio and rotate ratio has a large difference.

Environmental perception is a crucial subsystem in autonomous vehicles. In order to build safe and efficient traffic transportation, several researches have been proposed to build accurate, robust and real-time perception systems. Camera and LiDAR are widely equipped on autonomous 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 two sensors) should balance the degree of alignment between each two sensors.

The vibration characteristics of hybrid vehicles are very different from that of traditional fuel vehicles. In this paper, the active and passive control schemes are used to inhibit the vibration issues in vehicle hybrid powertrain system. Firstly the torsional vibration mechanical model including engine, motor and planetary gear subsystems is established. Then the transient vibration responses of typical working condition are analyzed through power control strategy. Consequently the active and passive control of torsional vibration in hybrid powertrain system is proposed. The active control of the motor and generator torque is designed and the vehicle longitudinal vibration is reduced. The vibration of the planetary gear system is ameliorated with passive control method by adding torsional vibration absorbers to power units. The vibration characteristics in vehicle hybrid powertrain system are effectively improved through the active and passive control.

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.

Electric power steering systems (EPS) greatly improve fuel performance over conventional hydraulic power steering systems, and therefore being increasingly adopted. However, it is very important to evaluate the mechanical noise and to identify the correct noise source in steering systems, because an EPS has vibration sources such as at the motor gear reducer, manual gears and intermediate joints. In order to identify the noise source, a technique based on time-frequency analysis using the wavelet transform (WT) has been focused on which uses a mother wavelet (MW) that is derived mathematically. The measured signal is adopted as the MW. In this study, applying this method to time-varying signals, a new concept of the Wavelet Instantaneous Correlation Value (WICV) is discussed and is used to identify the noise source.

The prevention and control of brake judder and its various negative effects has been a key target of vehicle production. One of the effects is the steering wheel vibration during vehicle braking. Experimental and theoretical investigation into “steering wheel vibration due to brake judder” is extensively presented in this paper. The vehicle road test is carried out under controlled braking conditions. During the test, the accelerations of brake caliper assembly, suspension low and upper control arm, steering arm, tie rod and steering wheel, left and right wheel rotary speed, are measured by a multi-channel data acquisition system. The data processing focuses on order tracking analysis and transfer path analysis to work out the related resonant components. A disc brake assembly, with deliberately designed disc thickness variation and surface run-out combinations, is tested on a brake dynamometer.

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.

A Steer-by-wire (SBW) system, which has no mechanical linkage, is expected to support the driver even in critical situations so as to improve collision safety and cockpit design flexibility. We have shown the effectiveness of driver assistance using an active steering control integrated with active braking control.[1] This is a case of normal driving without any vital component failures. The SBW system failure, however, can lead to an unsafe driving situation. A highly redundant design reduces the SBW failures but complicates its design and increases cost, volume and weight. This paper proposes a new fault-tolerant architecture to cope with the SBW failure. This is based on an integrated control by SBW, active braking, and driving torque distribution. A feasibility study is made using a driving simulator experiment during front obstacle avoidance under failed SBW.

Electric Power Steering (EPS) is the actuator of several lateral-dynamic-related Advanced Driver Assistance Systems (ADAS). A driving simulator with EPS will be much helpful for the ADAS development. However, if a real EPS is used in the driving simulator, it is quite difficult to realize the road reaction force accurately and responsively. To overcome this weakness, a virtual EPS platform is established. The virtual EPS platform contains two parts: one is the vehicle and EPS model, the other is the force feedback actuator (FFA) of the Steer-by-Wire (SBW) system. The FFA is an interface between the driver and the EPS/vehicle model. The reactive torque of the FFA is obtained based on the models. Meanwhile, the input of the EPS model is the steering angle of the FFA. Comparing to a real EPS, the virtual EPS platform has a problem of instability because of the actuator lag of the FFA. Therefore, a damping control method is applied to make the system stable.

Based on the emergency lane change cases extracted from the China naturalistic driving data, the driving steering behavior divides into three phases: collision avoidance, lateral movement and steering stabilization. Using the steering primitive fitting by Gaussian function, the distribution of the duration time, the relationship between steering wheel rate and deflection were analyzed in three phases. It is shown that the steering behavior essentially is composed of steering primitives during the emergency lane-change. However, the combination of the steering primitives is different according to the specific steering constraints in three phases. In the collision avoidance phase, a single steering primitive with high peak is used for the fast steering; in the lateral movement and stabilization phase, a combination of two or even more steering primitives is built to a more accurate steering.

Noise signals of the driver’s right ear include those of engine, environment, chassis dynamometer, loaded gears and unloaded gears when they are recorded in full vehicle on chassis dynamometer in semi-anechoic room. Gear rattle noise signals of the driver’s right ear caused by unloaded gear pairs can’t be identified or quantified directly. To solve the problems, relative approaches are used to identify and quantify the gear rattle noise signals. Firstly, the rattle noise signals of the driver’s right ear are filtered by human ear characteristic functions and steady noise signals are extracted by regression and smoothing processes. The noise signals are regressed at 200ms interval in the hearing critical frequency bands and smoothed in the flanking frequencies. Then, the noise relative approaches are obtained by subtracting the steady noise signals from the filtered noise signals, which are the transient noise signals of the unloaded gear pairs inducing the rattle noise.

Generally, the gear rattle noise prediction models are composed of the mass and stiffness elements. The proposals are about the gear inertia or backlash and the shaft inertia or stiffness, but there are many detailed designs in the same inertia, stiffness or backlash conditions. Therefore, these proposals can’t guide detailed designs. These models only investigate the rattle in the rotating degree, and ignore rattle contribution in the radical and axial directions. Those prediction models only consider one or several factors which affect the rattle noise performance. It is difficult to predict the influence of individual factor and multi-factors coupling on the gear rattle noise in a rattle simulation model.

Sealing system is an important subsystem of modern high-performance engine. Sealing system reliability directly affects the engine operating conditions. Cylinder head gaskets(CHG) sealing system is of the most importance to the engine sealing system, which is not only responsible for sealing chamber, the cooling fluid and lubricating oil passage, for preventing gas leakage, water leakage and oil leakage, but also responsible for force transferring between cylinder head and cylinder body. Basing on nonlinear solution method, the sealing performance of multi-layer-steel cylinder head gaskets to a gasoline engine is studied with the finite element software ABAQUS. The deformations of the cylinder liners and engine block are also considered.

Path tracking is the rudimentary capability and primary task for autonomous ground vehicles (AGVs). In this paper, a novel four-wheel-independent-steering (4WIS) and four-wheel-independent-drive (4WID) electric vehicle (EV) is proposed which is equipped with steer-by-wire (SBW) system. For path-tracking controller design, the nonlinear vehicle model with 2 degrees of freedom (DOF) is built utilizing the nonlinear Dugoff tire model. The nonlinear dynamic model of SBW system is conducted as well considering the external disturbances. As to the path-tracking controller design, an integrated four-wheel steering (4WS) and direct yaw-moment control (DYC) system is designed based on the model predictive control (MPC) algorithm to track the target path described by desired yaw angle and lateral displacement. Then, the fast terminal sliding mode controller (FTSMC) is proposed for the SBW system to suppress disturbances.

In the recent years, the interaction between human driver and Advanced Driver Assistance System (ADAS) has gradually aroused people’s concern. As a result, the concept of personalized ADAS is being put forward. As an important system of ADAS, Lane Keeping Assistance System (LKAS) also attracts great attention. To achieve personalized LKAS, driver lane keeping characteristic (DLKC) indices which could distinguish different driver lane keeping behavior should be researched. However, there are few researches on DLKC indices for personalized LKAS. Although there are many researches on modeling driver steering behavior, these researches are not sufficient to obtain DLKC indices. One reason is that most of researches are for double lane change behavior which is different from driver lane keeping behavior. The other reason is that the researches on driver lane keeping behavior only provide model structure and rarely discuss identification procedure such as how to select suitable data.

Electromechanical Braking System (EMB) stops the wheel by motor and related enforce mechanism to drive braking pads to clamp the friction plate. It is compact in sized as well as faster in response, which solves the issue of potential leakage and slows response of traditional hydraulic brake system. The institutions at home and abroad have put forward all kinds of new structural schemes of EMB. At present, there are various EMB structural schemes, but the analysis and evaluation of these schemes are relatively few. In this paper, on the basis of a large number of research, the EMB actuator is modular decomposed according to function ,then the parametric 3D model library of each function module is established. According to brake requirements of the target vehicle, a development platform is set up to match EMB actuator structure scheme quickly.

An electronic waste-gated turbocharger for automotive application can accurately control the boost pressure and effectively reduce turbo-lag. It can improve the transient responsive performance of engine and the acceleration performance of vehicle, which makes vehicle have a better adaptation to the complex traffic environment. A detailed analysis of aerodynamic working principle of electronic wastegate is the foundation for designing the control strategy of electronic wastegate. Putting turbine with electronic wastegate under unsteady condition that simulates the pulse exhaust gas of engine and studying influences of different valve opening on the performance of turbine has the practical value. This paper sets fixed and periodical unsteady conditions and adopts numerical methods to explore the performance of turbine in twin-entry turbocharger and the flow loss of bypass. Steady simulation structure is given for reference.

The electromagnetic valve actuator (EMVA) is considered a technological solution for decoupling between crankshaft and camshaft to improve engine performance, emissions, and fuel efficiency. Conventional EMVA consists of two electromagnets, an armature, and two springs has been proved to have the drawbacks of fixed lift, impact noise, complex control method and large power consumption. This paper proposes a new type of EMVA that uses voice coil motor (VCM) as electromagnetic valve actuator. This new camless valvetrain (VEMA) is characterized by simple structure, flexible controllable and low actuating power. VCM provides an almost flat force versus stroke curve that is very useful for high precision trajectory control to achieve soft landing within simple control algorithm.

Wind noise becomes the foremost noise source when a car runs at high speeds. High frequency characteristics of wind noise source and effective performance of seal rubbers for insulating leakage noise make research on the Transmission Loss (TL) of automotive door sealing systems significant. The improvement of TL of automotive door sealing system could effectively decrease the interior noise due to wind noise for vehicles at high speeds. In this study, compression simulation of seal rubbers for an automotive door is performed through a Finite Element (FE) tool firstly. Compressed geometries of the seal rubbers are obtained. Then, based on the final compressed geometries and pre-stress modes of the automotive door seal rubbers, the TL of the whole door sealing system is acquired by hybrid Finite Element - Statistic Energy Analysis (FE-SEA) method. The fluctuating surface pressure on a car body was captured by a Computational Fluid Dynamics (CFD) tool.