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The adhesion control is the basic technology of active safety for the four-wheel driven EV. In this paper, a novel adhesion control method based on fuzzy logic control is proposed. The control system can maximize the adhesion force without road condition information and vehicle speed signal. Also, the regulation torque to prevent wheel slip is smooth and the vehicle driving comfort is greatly improved. For implementation, only the rotating speed of the driving wheel and the motor driving torque signals are needed, while the derived information of the wheel acceleration and the skid status are used. The simulation and road test results have shown that the adhesion control method is effective for preventing slip and lock on the slippery road condition.

A disc-pad system is established to study impacts of surface topography on brake squeal from the perspective of statistical analysis. Firstly, surface topographies of brake disc and pad are precisely measured on the scale of micron and are statistically analyzed with a three-dimensional evaluation system. Secondly, the finite element model of brake disc and pad without surface topographies is created and verified through component free modal tests. Thereby the valid brake squeal model for complex modal analysis is built with ABAQUS. An effective method is developed to apply interface topographies to the smooth contact model, which consequently establishes sixty brake squeal models with topographies. Thirdly, impacts of surface topography on brake squeal are studied through comparison and statistical analysis of prediction results with and without topographies.

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.

A passive thermal management system (TMS) using composite phase change material (PCM) for large-capacity, rectangular lithium-ion batteries is designed. A battery module consisting of six Li-ion cells connected in series was investigated as a basic unit. The passive TMS for the module has three configurations according to the contact area between cells and the composite PCM, i.e., surrounding, front-contacted and side-contacted schemes. Firstly, heat generation rate of the battery cell was calculated using the Bernardi equation based on experimentally measured heat source terms (i.e. the internal resistance and the entropy coefficient). Physical and thermal properties such as density, phase change temperature, latent heat and thermal conductivity of the composite PCM were also obtained by experimental methods. Thereafter, thermal response of the battery modules with the three TMS configurations was simulated using 3D finite element analysis (FEA) modeling in ANSYS Fluent.

Gas distribution of proton exchange membrane fuel cells (PEMFCs) is mainly decided by flow field of bipolar plate. The improper design of distributing channel, nonuniform gas flow distribution and current density distribution among different straight channels are the leading factors that could tremendously undermine the performance and life expectancy of the cell. However, there is lack of research focusing on distributing channel in straight-parallel flow field. In this work, a three-dimensional numerical model of PEMFC cathode flow field is developed with CFD method to investigate the effects of configuration type and width of the distributing channel on pressure distribution in distributing channel and on reactant flow distribution, pressure drop and concentration distribution in multiple straight channel. Effects of electrochemical reaction and formation of water on the flow distribution are taken into consideration.

The noise and vibration of electric vacuum pump (EVP) become a major problem for electric vehicles when the vehicle is stationary. This paper aims at the EVP’s abnormal noise of an electric vehicle when stationary. Driver’s right ear (DRE) noise was tested and spectrogram analysis was carried out to identify the noise sources. In order to attenuate this kind of abnormal noise, a new EVP rubber mount with a segmented structure was introduced, which optimized the transfer path of vibration. Then dynamic stiffness and fatigue life of the EVP mount with different rubber hardness were calculated through finite element analysis (FEA) approach. Bench tests of fatigue life and DRE noise were performed to validate the FEA results. Test data of the sample mount shows that sound pressure level of DRE was dramatically attenuated and thus passengers’ ride comfort was enhanced.

A compiled method of the programmed load spectrum, which can simplify and accelerate the fatigue bench test of a car body, is proposed and its effectiveness is checked by the fatigue simulation. By using the multi-body dynamics model with a satisfactory accuracy, the virtual iteration is applied to cascade body loads from the wheel hubs. Based on the rain-flow counting method and statistics theory, the distributions of the body loads are analyzed, and then the programmed load spectrum is compiled and simplified. Through comparative study, the simulation results of random and programmed load spectrum are found to agree well with each other in terms of the damage distribution and fatigue life, which demonstrates the effectiveness of the presented method.

With the rapidly developing automotive industry and stricter environmental protection laws and regulations, lightweight materials, advanced manufacturing processes and structural optimization methods are widely used in body design. Therefore, in order to evaluate and improve the pedestrian protection during a collision, this paper presents an impact simulation modeling and structural optimization method for a sport utility vehicle engine hood made of carbon fiber reinforced plastic (CFRP). Head injury criterion (HIC) was used to evaluate the performance of the hood in this regard. The inner panel and the outer panel of CFRP hood were discretized by shell elements in LS_DYNA. The Mat54-55 card was used to define the mechanical properties of the CFRP hood. In order to reduce the computational costs, just the parts contacted with the hood were modeled. The simulations were done in the prescribed 30 impact points.

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.

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.

Recently, electro-hydraulic brake systems (EHB) has been developed to take place of the vacuum booster, having the advantage of faster pressure build-up and continuous pressure regulation. In contrast to the vacuum booster, the pressure estimation for EHB is worth to be studied due to its abundant resource (i.e. electric motor) and cost-effective benefit. This work improves an interconnected pressure estimation algorithm (IPEA) based on actuator characteristics by introducing the vehicle dynamics and validates it via vehicle tests. Considering the previous IPEA as the prior pressure estimation, the wheel speed feedback is used for modification via a proportional-integral (PI) observer. Superior to the IPEA based on actuator characteristics, the proposed PEA improves the accuracy by more than 20% under the mismatch of pressure-position relation.

It is very important to investigate how road irregularity excitation will affect the durability, reliability, and performance degradation of fuel cell vehicle powertrain and its key components, including the electric motor, power control unit, power battery package and fuel cell engine system. There are very few published literatures in this research area. In this paper, an elementary but integrated experimental work is described, including the real road load sample on proving ground, road load reproduction on vibration test rig, total vehicle road simulation test and key components vibration tests. Remote parameter control technology is adopted to reproduce the real road load on road simulator and six-degree-of-freedom vibration table, which is used respectively for total vehicle and components vibration tests.

This paper describes a methodology to estimate longitudinal velocity of a 4-wheel-drive electric vehicle, in which wheel driven torque can be independently controlled by electric motor. Without non-driven wheels it would be difficult to estimate the vehicle longitudinal velocity precisely, especially when all of four wheels have large slip ratio. Therefore, an estimation methodology based on fuzzy logic is put forward, which uses four wheel speed and longitudinal acceleration as input signals. However, this method works not very well when two or more wheels have large slip ratio. In order to improve estimation effect, a state variable filter is designed to calculate wheel acceleration signals, which are used as additional signals to the fuzzy logic observer. Furthermore, the possibility of using four wheel driving torque signals to improve the estimation precision is also discussed.

This paper describes a methodology to estimate yaw rate of a 4-wheel-drive electric vehicle, in which wheel driven torque can be independently controlled by electric motor. Without non-driven wheels it would be difficult to estimate the vehicle yaw rate precisely, especially when some of the four wheels have large slip ratio. Therefore, a model based estimation methodology is put forward, which uses four wheel speeds, steering wheel angle and vehicle lateral acceleration as input signals. Firstly the yaw rate is estimated through three different ways considering both vehicle kinematics and vehicle dynamics. Vehicle kinematics based method has good estimation accuracy even when the vehicle has large lateral acceleration. However, it can not provide satisfying results when the wheel has large slip ratio. In contrast, vehicle dynamics based method is not so sensitive to wheel slip ratio.

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.

In order to investigate the impacts of recirculated exhaust gas temperature on gasoline engine combustion and emissions, an experimental study has been conducted on a turbocharged PFI gasoline engine. The engine was equipped with a high pressure cooled EGR system, in which different EGR temperatures were realized by using different EGR coolants. The engine ran at 2000 r/min and 3000 r/min, and the BMEP varied from 0.2MPa to 1.0MPa with the step of 0.2MPa. At each case, there were three conditions: 0% EGR, 10% LT-EGR, 10% HT-EGR. The results indicated that LT-EGR had a longer combustion duration compared with HT-EGR. When BMEP was 1.0 MPa, CA50 of HT-EGR advanced about 5oCA. However, CA50 of LT-EGR could still keep steady and in appropriate range, which guaranteed good combustion efficiency. Besides, LT-EGR had lower exhaust gas temperature, which could help to suppress knock. And its lower exhaust gas temperature could reduce heat loss. These contributed to fuel consumption reduction.

This paper aimed at a gasoline engine "cylinder head- cylinder gasket-cylinder body-bolt" sealing system, built the 3D solid model and the finite element model of the assembly, and calculated the stress and strain of the cylinder gasket under the cylinder pressure and the deformation of the engine block. In addition, based on the calculation results, this paper put forward the optimization scheme of the cylinder gasket structure, re-established the simulation model, and get the calculation results. The calculation results showed that the cylinder pressure had influence on the sealing performance of the cylinder gasket, and the influence of cylinder pressure should be taken into consideration when designing the cylinder gasket. When the cylinder pressure was applied, the overall contact stress of the cylinder gasket had decreased, and the whole remaining height of the gasket had increased.

Biodiesel as a renewable energy is becoming increasingly attractive due to the growing scarcity of conventional fossil fuels. Meanwhile, the development of after-treatment technologies for the diesel engine brings new insight concerning emissions especially the particulate matter pollutants. In order to study the coupling effects of biodiesel blend and CCRT (Catalyzed Continuously Regeneration Trap) on the particulate matter emissions, the particulate matter emissions from an urban bus with and without CCRT burning BD0 and BD10 respectively was tested and analyzed using electrical low pressure impactor (ELPI). The operation conditions included steady state conditions and transient conditions. Results showed that the particulate number-size distribution of BD10 and BD0 both had two peaks in nuclei mode and accumulation mode at the conditions of idle, low speed and medium speed while at high speed condition the particulate number-size distribution only had one peak.

Due to much higher pressure and pressure rising rate, knocking is always of potential hazards causing damages in the engine and high NOX emissions. Therefore, the researchers have focused on knocking diagnosis and control for many years. However, there is still lack of fast response sensor detecting in-cycle knocking. Until now, the feedback control based on knocking sensor normally adjusts the injection and ignition parameters of the following cycles after knocking appears. Thus in-cycle knocking feedback control which requires a predictive combustion signal is still hard to see. Ion current signal is feasible for real-time in-cylinder combustion detection, and can be employed for misfiring and knocking detection. Based on incylinder pressure and ion current signals, the in-cycle knocking feedback control is investigated in this research. The 2nd-order differential of in-cylinder pressure, which means the response time of pressure rising rate dPR, is employed for knocking prediction.

With regulatory standards for diesel engine emissions becoming stricter worldwide, integrated catalytic systems are becoming increasingly necessary. One of the better approaches is to use an after-treatment system consisting of a diesel oxidation catalyst (DOC), a catalyzed diesel particulate filter (CDPF), and a selective catalytic reduction (SCR), but many factors can affect how well this system works. This study investigates the effects of DOC and CDPF catalyst composition on emissions characteristics for DOC + CDPF + SCR systems by collecting reactor and engine data. The reactor results show that the light-off temperatures (T50) of CO and C3H6 increase with the growth of Pt:Pd ratio while the T50 of NO degrades. An engine dynamometer test was conducted on a light-duty diesel engine equipped with DOC + CDPF + SCR. The results show light-off curves of CO and THC that are smoother than the reactor data.