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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.

During the operation of the ball joint, its service life and transmission efficiency are affected by the internal friction. Taking the ball joint as the research object, based on fractal theory, the friction between the steel ball and the raceway inside the ball joint of an automotive drive shaft system is studied in this paper. During the analysis, the friction between the steel ball and the arc raceway is regarded as the friction between a sphere and an arc raceway surface. In order to describe the friction state more accurately, this paper proposes a correction coefficient to modify the distribution function of contact asperities in the plane, and obtains the distribution function of contact asperities between the sphere and the arc raceway surface. The correction coefficient is related to the load, the size parameters and the material parameters of the steel ball and the raceway.

Design of powertrain mounting bracket is always challenging in achieving good NVH characteristics, sound durability and simultaneously reduced weight. Structural optimization is an effective tool to obtain an optimum design. Depending on the design status, different schemes, i.e. size, topology and shape optimization, are applied. In this paper, a case study of application of structural optimization in the design of a mount bracket has been presented. Firstly, both test and FEA (Finite Element Analysis) results expose problems of the initial design. Therefore, it is necessary to redesign the bracket. With sufficient design freedom and time in topology optimization, design space and optimization parameters are defined. Die direction and other manufacturability considerations for the casting components are vital. Shape optimization is then conducted to further decrease the weight and refine local weakness.

Experimental investigation on a high speed single-cylinder diesel engine has shown that a gas-pressure stabilizer in the exhaust system has obvious effect upon engine performance. Two types of such gas pressure stabilizers were tested, and a reduction of about 0.5% to 2% in fuel consumption rate was achieved, which was mainly dependent on the type of stabilizer employed and was more significant under higher speed conditions.

The ever increasing popularity of electric vehicles and higher requirement on safety and comfort has led heat pump air conditioning system indispensable in electric vehicle. Many studies have shown that the addition of nano particles contributes to great improvement on thermal conductivity than that of conventional refrigerants. Therefore, the application of the magnetic nanorefrigerant in heat pump air conditioning system has massive potential to heighten the heat transfer efficiency. This paper aims at studying the magnetic nanorefrigerant comprised of the magnetic nano powder Fe3O4 and refrigerant R134a. According to the relevant theoretical analyses and empirical formula, the heat transfer coefficient, density, viscosity, and other physical parameters are calculated approximately. In the heat pump air conditioning system of a certain type of electric vehicle, the special working condition parameters are selected to carry out calculation analysis with numerical analysis software.

Because the power unit of electric vehicle has large torque, the rubber mount of electric vehicle is fully compressed under the condition of full throttle acceleration. When designing the mount of electric vehicle, the dynamic-to-static stiffness ratio of mount under the case should be as low as possible to improve the vibration isolation rate of the mount. In this paper, a method for calculating the high frequency dynamic characteristics of rubber isolators under different preloads is presented. Firstly, the dynamic characteristics of rubber specimens under various shear pre-strains were tested. The test results show that the dynamic stiffness of specimen decreases at first and then increases with the increase of shear strain. The viscoelastic parameters of rubber in frequency domain under different pre-strain were identified according to the experimental data. Secondly, a finite element modeling method was proposed.

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.

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.

In the existing literature concerning the calculation of the output speed of the silicone oil fan clutch and the silicone oil temperature, the theoretical calculation method is all adopted to establish the calculation formulas of moment transmission and silicone oil shear viscous heat by extracting the structural parameters of the clutch model, in order to solve the output speed and silicone oil temperature of the clutch under stable working state. At present, CFD (Computational Fluid Dynamics) numerical simulation method has not been used to solve the problem. In this paper, the CFD simulation method is used for the first time. Considering the change of silicone oil viscosity with temperature, a double-sided slot silicone oil fan clutch was taken as the research object to established the CFD simulation model of hydro-viscous drive to solve the clutch output speed and silicone oil temperature.

The decoupling brake-by-wire system controls the key components of the flow path and liquid flow of the whole brake system through the solenoid valve of the bottom control unit. The reference cross-sectional area value at the valve inlet is obtained by calculation, and the valve body structure model is established. The flow channel structure is extracted, and the porous media model is used to replace the fluid area of the filter screen at the entrance of the solenoid valve. The Fluent software is used to analyze the influence on the flow characteristics of the solenoid valve with or without a filter. The accuracy of the model is verified by the experimental results, which also show that the porous medium can effectively and accurately reflect the characteristics of the solenoid valve end filter.

The static characteristics of solenoid valve play an important role in the performance of brake system and can indirectly reflect the response speed of the brake system. The static characteristics of the solenoid valve reflect the electromagnetic characteristics of the solenoid valve itself, revealing the maximum potential of the solenoid valve in the system work, which is one of the important characteristics to characterize the working ability of the solenoid valve. In this paper, a numerical calculation method is used to build a finite element model of the solenoid valve electromagnetic field on the Ansoft Maxwell simulation platform. The model takes into account the nonlinear magnetization characteristics of soft magnetic materials and the air gap.

A new type ECCVT system is studied. It consists of a rotor and a stator with iron winding, an additive magnetic field adjusting winding, a cup-type rotor with special magnetic pole, inductive slip rings and power electronic controller. Its specialty is that the traditional electric transmission and electromagnetism coincidence are combined and the electricity is transferred unosculantly, so that the power split is realized. The new system also puts up a compact topology, good control and stability by the way of frequency conversion and magnetic field adjusting. The system not only has a wide continuously variable range as the traditional Electric Motor, but also has a high efficiency. Being used on a car, the clutch and starter are omitted. It also can be used as the driving line of the HEV.

Roll stability is an important attribute which must be accounted for in heavy trucks. In order to analyze the anti-roll performance of the suspension in the early period of development, engineers will generally use Multi Body Dynamics (MBD) simulation software which can save time in the product development cycle. However, air suspension employs levelling valves to adjust the height by charging and discharging air springs. The air spring is typically modeled as a closed container in the simulation; the stiffness change of the air spring caused by the levelling valve is not considered. In this paper, an air suspension with levelling valves model integrated into the multi-body dynamic model of a 6�4 heavy truck is built with a co-simulation technique to investigate the influence of three types of levelling valves arrangement on the roll performance of the suspension under two typical conditions.

MAZ is a fuel additive designed to reduce tailpipe emissions. It was developed by Magnum Environmental Technologies, Inc., and is covered by US Patent Number 6319294. The patent for MAZ is protected in about 120 countries around the world. Its main components are a combination of nitroparaffins. MAZ exhibits high heat value, excellent carbon deposit prevention, lubricity and high chemical reactivity that results in the development of free radicals in the course of the combustion process. This, in turn, initiates a chain reaction providing more complete combustion. This results in lower tail pipe emissions and fuel economy. Further, MAZ has low water solubility, is biodegradable and contains no metallic substances making it environmentally friendly. Aside from tests currently underway in the USA, Singapore and Indonesia, China has completed applications testing with leading authorities.

Current gasoline-gas vapor recovery system is incomplete, for it cannot adjust the vapor-liquid ratio automatically due to the change of working temperature. To solve this problem, this paper intends to design a new system and optimize its parameters. In this research, variables control method is used for tests while linear regression is used for data processing. This new system moves proportion valve away and adds a DSP control module, a frequency conversion device, and a temperature sensor. With this research, it is clearly reviewed that the vapor-liquid ratio should remains 1.0 from 0 °C to 20 °C as its working temperature, be changed into 1.1 from 20 °C to 25 °C, be changed into 1.2 from 25 °C to 30 °C, and be changed into 1.3 when the working temperature is above 30 °C.

Multi-body dynamics simulation is widely used in the dynamic research of constant velocity joints (CVJ). Useful kinematic and dynamic conclusions can be obtained from simulations to replace part of the test process and reduce test costs. In this paper, multi-body dynamics parameterized (MBDP) models of the high-efficiency constant velocity joints are proposed in the software of ADAMS. A friction model and Hertz contact theory are applied to describe the contact status. And the torque transmission efficiency of the kind of high-efficiency CVJ is calculated through the MBDP model. Bench tests of torque transmission efficiency are carried out on the CVJ to verify the calculation accuracy of the multi-body dynamics model. And the test result of high-efficiency joint shows an excellent behavior for efficiency when compared with BJ.

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.

An Inline 4-cylinder engine is equipped with second-order balance shafts.When the engine is running under full load in 5000rpm,the engine generated severe structural radiation noise.The bench test analysis shows that the main reason is the resonance of the engine near 800Hz and 1500Hz. In this paper, a method for modeling and analyzing the vibration of the engine structure is proposed, and the sound quality of the engine is evaluated and imporved by the Moore–Glasberg loudness method. Firstly, the finite element model of the engine was established, and the experimental modes of the engine casing assembly, crankshaft and balance shaft were measured. The natural frequencies and modal shapes obtained by calculation and experiment were compared, which validates the established finite element model.Secondly, a flexible multi-body dynamic model of the engine was established.

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.

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.