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A fourth-order mathematical model for I-EHB (integrated electro-hydraulic brake) system was derived from its mechanical and hydraulic subsystems. The model was linearized at equilibrium state and then was verified by AMESIM software. The friction model of the system was analyzed based on static friction and viscous friction. A bench test was designed to identify the parameters of friction model. As the I-EHB system worked at different braking conditions, a PID-based switching controller was designed to track the target servo cylinder pressure. Both simulations and experiments results showed that, the response time of pressure was less than 120ms, and there was no overshoot, which helped handling different braking conditions and improving the braking safety and comfort.

An Inline 4-cylinder engine is equipped with second-order balance shafts. When the engine is running under no-load acceleration conditions, the gear system of the balance shaft generated whine noise. In this paper, an analysis and experiment method for reducing the whine noise is presented. First, a flexible multi-body dynamic model of the engine is established, which includes shaft and casing deformation, micro-modification of the gears. Taking the measured cylinder pressure as input, the load on each gear of balance shaft gear system is calculated. In addition, the influence of tooth surface micro-modification on the meshed noise was analyzed. The results show that the dynamic meshing force between the crank gear and the shim gear is large under the original tooth surface micro-modification parameters, which is the main reason of the whine noise.

A model for a generic layout of an engine front end accessory drive system is established. The dynamic performances of the system are obtained via a numerical method. The dynamic performances consist of the oscillation angle of tensioner arm, the slip ratio of each pulley and the dynamic belt tension. In modeling the system, the hysteretic behavior of an automatic tensioner, the loaded torque of the accessory pulley versus the engine speed, the torsional vibration of crankshaft and the creep of the belt are considered. The dynamic performances of the system at steady state and under accelerating condition are analyzed. An example is provided to validate the established model. The measured results show that the torsional vibration of crankshaft is larger and the dynamic performances of the system are different under accelerating conditions, though the acceleration is small.

The driving pulley is often used as a Torsional Vibration Damper (TVD) for the crankshaft in the front end accessory drive (FEAD) system. Although the crankshaft torsional vibrations are dampened, they are transmitted to the belt transmission and therefore to the driven accessories. The isolation pulley is a new device to reduce the belt tension fluctuation by isolating the belt transmission from the crankshaft torsional vibrations. A five-pulley system with isolation pulley is presented and a non-linear model is established to predict the dynamic response of the pulleys, tensioner motion, tension fluctuation and slippage. The model works in the time domain with Runge-Kutta time-stepping algorithm. The numerical simulation results of harmonic excitations show that the amplitudes of the belt tension fluctuation and the vibrations of each component are reduced significantly. Moreover, the effect of isolation pulley parameters on the system natural frequencies is demonstrated.

The application of turbochargers in fuel vehicles brings high-frequency noise, which seriously affects the vehicle's ride comfort. The hiss noise of a turbocharged car is improved in this paper. Firstly, under different operating conditions and whether the air intake system is wrapped, the noise in the vehicle cabin and the driver's right ear is tested, and the noise sources and noise characteristics are identified. Then, the acoustic calculation model of the muffler is established, and the transmission loss (TL) of the original muffler behind the turbocharger (MBT) is calculated. The TL of the muffler is measured by the double-load impedance tube method. The finite element calculation model is verified by comparing the TL of muffler calculated with tested. Thirdly, the MBT is redesigned. The improved muffler significantly improves the performance of eliminating high-frequency noise, and its TL beyond 20 dB is expanded to the band of 1600 ~ 3500 Hz.

Hydraulic Engine Mount (HEM) is now widely used as a highly effective vibration isolator in automotive powertrain. A lumped parameter model is a traditional model for modeling the dynamic characteristics of HEM, in which the system parameters are usually obtained by experiments. In this paper, Computational Fluid Dynamics (CFD) method and nonlinear Finite Element Analysis (FEA) are used to determine the system parameters. A Fluid Structure Interaction (FSI) FEA technique is used to estimate the parameters of volumetric compliances, equivalent piston area, inertia and resistance of the fluid in the inertia track and decoupler of a HEM. A nonlinear FEA method is applied to determine the dynamic stiffness of rubber spring of the HEM. The system parameters predicated by FEA are compared favorably with experimental data and/or analytical solutions.

Electromagnetic semi-active hydraulic engine mount (HEM) with double inertia tracks can realize the opening and closing of the inertia tracks through the control of electromagnetic actuator, so as to meet the needs of vibration isolation in different working conditions, but the cost is high. In this paper, without using electromagnetic actuator, a mechanical semi-active HEM with double inertia tracks is designed and manufactured with simple structure and low cost. In this study, the feature of mechanical semi-active HEM with double inertia tracks is that a baffle-current limiting column structure is added in the inertia track. Under different excitation amplitudes, the baffle-current limiting column structure can open and close the inertia track passively. Several mechanical semi-active HEM with double-inertia tracks samples and conventional inertia tracks HEM samples are manufactured and the dynamic characteristics of these samples under low frequency excitation are tested.

Experimental methods for measuring static and dynamic characteristics of an engine Frond End Accessory Drive System (FEADS) are presented. The static performance of a FEADS is the static tension of the belt, and the dynamic properties of a FEADS are transverse vibration of belt, and rotational vibration performances that include rotational response of pulleys and tensioner arm, dynamic tension of belt span, slip factor between belt and pulley. A mathematical model and calculation method for rotational vibration analysis of a 8 pulley-belt FEADS is established. In the model, creeping effect of a belt on pulley wrap arc, viscous damping and dry friction of a tensioner are considered. In calculation of dynamic performances of the FEADS, the excitation torques with multi-frequency components from crankshaft torsional vibration are obtained from the measurement.

Electronic expansion valve as a throttle element is widely used in heat pump systems and flow characteristics are its most important parameter. The flow characteristics of the electronic expansion valve (EXV) with a valve port diameter of 3mm are studied, when the refrigerant R134a is used as the working fluid. The main factors affecting the flow characteristics are researched by adopting the orthogonal experiment method and single factor control method, for example, inlet pressure, inlet temperature, outlet pressure and valve opening. The results show that the expansion valve opening degree has the greatest influence on mass flow rate. In view of the complicated phase change of the refrigerant passing through electronic expansion valve, it is difficult to model the flow characteristics accurately.

Two-layer engine front end accessory drive systems (TEFEADS) are adopted generally by commercial vehicles due to the characteristics of the accessory pulleys, which have large torque and moment of inertia. An overrunning alternator decoupler (OAD) is an advanced vibration isolator which can reduce the amplitude of torsional vibration of alternator rotor effectively by an one-way transmission and they are more and more widely used in vehicles. This paper established a model of a generic layout of a TEFEADS with an OAD. The coupling effect between the TEFEADS, the nonlinear characteristics of OAD, the torsional vibration of crankshaft and the creeping on the belt were taken into account. A nine pulleys model was provided as a study example, the dynamic responses, which are respectively under steady and accelerating conditions, of the system were calculated by the established method and compared with the bench experiment.

In order to study the influence of engine silicone oil fan clutch on the performances of engine cooling system under different control strategies, a model of engine cooling system for light truck is established. The working characteristics of the silicone oil clutch and the measured performance parameters of the cooling system components are taken into account in our proposed model. Modeling methods for different silicone oil fan control strategies are also given. Using the established model, the performance parameters under different vehicle speeds, such as coolant temperature of engine outlet and power consumption of cooling fan, are calculated and analyzed. The in-suite measurement of the engine cooling system is carried out to get the temperatures of engine coolant inlet and outlet from engine ECU. The model is validated by the comparison between the calculation and the measured results.

A battery cooling system model of electric vehicle was established. The system model consists of a battery pack, a pump, a radiator, and a fan. A cooling plate was used to cool the battery pack, and the coolant flow rate in the cooling plate was controlled by the pump. The heat in the battery cooling system was released into the ambient air through the radiator. A finite element analysis model of the cooling plate was established to calculate the pressure drop of the cooling plate. A coupled dynamics model of the battery pack-radiator cooling system was established to simulate the temperature of the battery pack during charging and discharging. Tests were carried out to obtain the pressure drop of the cooling plate and the temperature of the battery pack under different working conditions. The simulation results and test results were compared and analyzed, and the accuracy of the models were verified.

With the development of light weight design and the high power output of an engine, and since the damping of rubber materials is relatively low, the effectiveness of torsional vibration (TV) control for an engine crankshaft with an ordinary Single Mode and rubber-damped TV Absorber (SMTVA) is limited. Here, a SMTVA references to a TVA with only one inertial mass. In this paper, the configurations of some Multi-Mode and rubber-damped TV Absorbers (MMTVA) having more than one inertial mass are introduced firstly, then a detailed procedure for modeling a torsional vibration system for a generic crankshaft system is presented. Thirdly, an optimization method for determining the design parameters of a MMTVA (mass ratios, frequency ratios and damping ratios) is developed. The proposed calculation method is based on reducing the torsional vibration of a crankshaft. An example is given for demonstrating the effectiveness of the proposed method and the MMTVA in reducing the TV of a crankshaft.

To study the heat dissipation performance of the multi-fan cooling module composed of multiple fans and a radiator, numerical models of the radiator and the multi-fan cooling module were established, and heat dissipation performance prediction analysis and application analysis were conducted. In modeling, the Effectiveness-Number of Transfer Units (ε − NTU) method is used to predict the heat dissipation performance of the radiator. The aerodynamic performance of the fan at any speed is obtained by the similarity theorem using the data obtained from the tests at a certain speed. The influence between the fan and the radiator was established by using the flow addition scheme. To validate the established model, heat dissipation performance using 36 radiators and 11 multi-fan cooling modules is measured, and the measured data are compared with the calculations.

As one of the key components of the heat pump system, the electronic expansion valve mainly plays the role of throttling and reducing pressure in the heat pump system. The refrigerant flowing through the orifice will produce complex phase change. It is of great significance to study the internal flow field by means of CFD calculations. Firstly, a three-dimensional fluid model is established and the mesh is divided. Secondly, the phase change model is selected, the material is defined and the boundary conditions are determined. According to the principle of the fluid passing through thin-walled small holes, the flow characteristics of electronic expansion valve are theoretically analyzed. Then the flow characteristics of expansion valve are numerically calculated, and a bench for testing mass flow rate of the expansion valve is built. Then the theoretical value, CFD value and experimental value are compared to verify the correctness of the established three-dimensional fluid model.

To enhance the transient vibration performance of the vehicle at key on and key off, a method for optimizing mount parameters of a powertrain mounting system (PMS) is proposed. Uncertainties of mount parameters widely exist in a PMS, so a method for optimizing mount parameters of a PMS, which treats the mount parameters of a PMS as uncertain, is also proposed in this paper. Firstly, a 13 degrees of freedom (DOFs) model including car body with 3 DOFs, a PMS with 6 DOFs and unsprung mass with 4 DOFs is established, and the acceleration of the active side of mounts is calculated. An experiment is carried out to measure the accelerations located at active and passive sides of each mount and the accelerations of seat track. A comparison is made between the measured and estimated accelerations, and the proposed model is validated. Two optimization methods for the PMS are proposed based on the developed 13 DOFs model.

When the automotive engine cooling fan is actually working, there is a process of interaction and coupling between the fluid and solid domains on the blades. In order to study the influence of the "fluid structure coupling" effect on the aerodynamic and structural performance of fans during operation, a fan performance calculation model was established with and without considering the fluid structure coupling effect of fans. We conducted aerodynamic performance tests on fans, tested the relationship between fan flow rate, static pressure, transmission efficiency and fan speed, and compared and analyzed the calculated fan performance. The aerodynamic performance and structural deformation of the fan were calculated under different flow rates, rotational speeds and environmental temperatures, with and without considering the coupling of fan blades and airflow. The calculation results were compared and analyzed.

The amplitude-sensitive nonlinear mathematical model of the hydraulic engine mount (HEM) with a free-floating decoupler is deduced through the theory of fluid dynamics. The model considers the amplitude-sensitive characteristics, such as local pressure loss of the inertial track and the decoupler, the amplitude-sensitive dynamic stiffness of main rubber, and the switch mechanism of the decoupler. A new model of decoupler’s switching mechanism is established, which makes parameter identification simpler comparing to the existing analogous models. The finite element method is used to identify parameters of the lumped-parameter model, such as the contact force between the decoupler plate and the cage, the stiffness of the main rubber, the equivalent piston area, the chambers’ compliances, etc. The lumped parameters of fluid track are obtained by fluid mechanics formula.

Due to the advantages of compact structure, stable operation, and low cost, the gerotor pumps are widely used in the cooling and lubricating system of automobiles. The multi-arc combined gerotor pump is a gerotor pump with a special profile. In this paper, the calculation method of the inner and outer rotor profile of the above-mentioned pump is introduced, and its meshing characteristics are analyzed. In general, three kinds of clearances would be processed to ensure the operation of the pump, named as tip clearance, axial clearance, and radial clearance. These clearances have a great impact on the performance of the pump so that it is important to design them. In response to this problem, this paper established a flow field characteristics model of the multi-arc combined gerotor pump based on computational fluid dynamics (CFD) method, and the effectiveness of the model is then verified through experiments.

Turbulence caused by the blade tip of engine cooling fan is one of important noise generating factors. Existing theoretical researches show that the bionic serrated designs applied at the front and rear edges of fan blades can effectively improve the airflow characteristics and reduce the aerodynamic noise. However, the effect of its application at the blade tip needs to be explored and verified. In this research, vehicle engine fans whose tips are designed and remodeled with different size of triangular serrated edge have been tested on airduct, to explore the fan static pressure and noise that caused by changing of period and amplitude size. The large eddy simulation (LES) and FW-H acoustic analogy method are adopted to calculate the transient noise of each designed fan.