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Vehicle parameters and operation conditions play a critical role in vehicular handling and stability. This study aimed to evaluate vehicle stability based on cornering tire stiffness integrated with vehicle parameters. A passenger vehicle is considered in which a two-state linear bicycle model is developed in the Matlab/Simulink. The effect of the vehicle parameters on lateral vehicle stability has been investigated and analyzed. The investigated parameters included CG longitudinal position, wheelbase, and tire cornering stiffness. Furthermore, the effects of load variation and vehicle speed were addressed. Based on a Fishhook steering maneuver, the lateral stability criteria represented in lateral acceleration, yaw rate, vehicle sideslip angle, tire sideslip angles, and the lateral tire force were analyzed. The results demonstrated that the parameters that affect the lateral vehicle stability the most are the cornering stiffness coefficient and the CG longitudinal location. The findings also indicated a positive correlation between vehicle properties and lateral handling and stability.

Automobile exhaust energy thermoelectric utilization can promote energy-saving and emission-reduction. Unexpected urban traffic conditions lead to the hot-end temperature instability of the exhaust pipe-mounted thermoelectric generator (TEG), and influence the TEG power generation efficiency. The heat conduction oil circulation located at the hot-end could smooth the temperature fluctuation, at the expense of larger system size and additional energy supply. This research improves the TEG hot-end temperature stability by installing solid heat capacity material (SHCM) to the area between the outer wall of the exhaust pipe and the TEG, which has the merits of simple structure, light weight and no additional energy consumption. The exhaust temperature and flow rate characteristics with various driving conditions are firstly studied for the target engine. Then the convective heat transfer models of SHCM’s hot-end and thermoelectric material’s cold-end are established. Meanwhile, SHCM thermal properties’ effects on the amplitude and response speed of the TEG hot-end temperature are studied. The candidate SHCM with the characteristics of low thermal resistance and high heat capacity is determined. And the heat transfer model going through from TEG’s hot-end to the cold-end is established. The results show that the SHCM significantly improves the TEG hot-end temperature stability but slightly reduces the average power output. When the engine working conditions change a lot, the SHCM’s improvement on the TEG hot-end temperature stability is more significant, but the reduction of the average power output becomes more remarkable.

The thermoelectric generator (TEG) plays a crucial role in converting the waste energy of exhaust into electricity, which ensures energy saving and increased fuel utilization efficiency. In the urban driving cycle, frequent vehicle operation, like deceleration or acceleration, results in continuous variation of the exhaust temperature. In order to make the operating performance stable, and to weaken the adverse effects of the frequent variation of the exhaust temperature on the lifetime and work efficiency of the electronic components of TEG systems, the output voltage of the thermoelectric (TE) module should stay more stable. This article provides an improved method for the temperature stability of the TE material hot side based on sandwiching material. From the view of the TEG system’s average output power and the hot side temperature stability of the TE material, the analyzing factors, including the fluctuation frequency of the exhaust temperature and the physical properties and thickness of the sandwiching material are evaluated, respectively, in the sine and new European driving cycle (NEDC) fluctuation condition of the exhaust temperature. The results show few effects of sandwiching material thickness with excellent thermal conductivity on the average output power. During the 150–170 s of the NEDC test condition, the minimum hot side temperatures with a BeO ceramic thickness of 2 mm and 6 mm are, respectively, 537.19 K and 685.70 K, which shows the obvious effect on the hot side temperature stability of the BeO ceramic thickness in the process of acceleration and deceleration of vehicle driving.

Impinging jet played an important role in cooling technology. The steady-state jet could be transformed into an oscillatory one based on the intrinsic flow instability mechanisms by using self-oscillating fluidic oscillators. In this paper, a high-performance microchannel heat exchanger based on a fluidic oscillator array was presented. The fluidic oscillators were tilted at an angle of 30° above the impinging surface to extend the influence area of the jets. The unsteady RANS turbulence models were adopted to study the fluid dynamic and heat transfer performance of the jet array. The time-resolved pressure field and velocity field were calculated to show that the parallel oscillators would produce three modes, including co-directional oscillation, reverse oscillation, and irregular oscillation, under synchronous and asynchronous output phases. The sweeping jets improved the heat removal performance by increasing the average Nusselt number and enlarging the influence range on the external flow field. The heat removal performance of the sweeping jets was almost equivalent under different oscillation modes.

The organic Rankine cycle (ORC) is an effective way to recovery the engine exhaust heat. The thermal stability of the evaporation system is significant for the stable operation of the ORC system. In this paper, the performance of the designed evaporation system which combines with the intermediate fluid for recovering the exhaust waste heat from a diesel engine is evaluated. The thermal characteristics of the target diesel engine exhaust gas are evaluated based on the experimental data firstly. Then, the mathematical model of the evaporation system is built based on the geometrical parameters and the specific working conditions of ORC. Finally, the heat transfer characteristics of the evaporation system are estimated corresponding to three typical operating conditions of the diesel engine. The result shows that the exhaust temperature at the evaporator outlet increases slightly with the engine speed and load. In the evaporator, the heat transfer coefficient of the Rankine working fluid is slightly larger than the intermediate fluid. However, the heat transfer coefficient of the intermediate fluid in the heat exchanger is larger than the exhaust side. The heat transfer areas of the evaporator in both the two-phase zone and the preheated zone change slightly along with the engine working condition while the heat transfer areas of the overheated zone has changed obviously. The maximum heat transfer rate occurs in the preheating zone while the minimum value occurs in the overheating zone. In addition, the Rankine working fluid temperature at the evaporator outlet is not sensitively affected by the torque and speed of the engine and the organic fluid flow is relatively stable. It is concluded that the intermediate fluid could effectively reduce the physical changes of Rankine working fluid in the evaporator outlet due to changes in engine operating conditions.

To reduce energy consumption or improve energy efficiency, the regenerative devices recently have drawn the public’s eyes. In this paper, a novel hydraulic energy-regenerative shock absorber (HERSA) is developed for vehicle suspension to regenerate the vibration energy which is dissipated by conventional viscous dampers into heat waste. At first, the schematic of HERSA is presented and a mathematic model is developed to describe the characteristic of HERSA. Then the parametric sensitivity analysis of the vibration energy is expounded, and the ranking of their influences is k1≫m2>m1>k2≈cs. Besides, a parametric study of HERSA is adopted to research the influences of the key parameters on the characteristic of HERSA. Moreover, an optimization of HERSA is carried out to regenerate more power as far as possible without devitalizing the damping characteristic. To make the optimization results more close to the actual condition, the displacement data of the shock absorber in the road test is selected as the excitation in the optimization. The results show that the RMS of regenerated energy is up to 107.94 W under the actual excitation. Moreover it indicates that the HERSA can improve its performance through the damping control.

Vehicle overload seriously affects the traffic safety, damages the road infrastructure, and the road service life is reduced. There are many shortcomings in the current detection methods for overloaded vehicles. Traditional static weighing stations are relatively fixed and affect the road traffic efficiency; the cost of weighing in motion station is high, while the precision is not enough; on-board weighing electronic products require the modification of vehicles, which is difficult to promote. In this paper, a non-contact overload detection method based on body vibration is proposed. After the analyzation of the body vibration response of dynamic vehicles under specific vibrational excitation, the load value data can be obtained combined with standard parameters and mathematical calculation model. Firstly, the body vibration response model under specific excitation is established. Then, roadbed facilities are arranged according to specific requirements, cameras calibration are finished, and the identification environment is built. Machine vision technology is used to identify the vibration track of the characteristic point on the vehicle body in the vertical direction. The vibration response characteristic parameters are extracted using the established response model. Finally, the vehicle load value data can be obtained by resolve the characteristic parameters. Compared with the rated load data in the database, the overload judgment of the vehicle is obtained. In the experiment part, the road speed-control hump was used as the vibration excitation source. The vehicle experiments were carried out with Dongfeng Aeolus S30 and Yuejin Shangjun X500. The results show that the load identification error can be controlled within 20%–30%. This method above can detect overload vehicles without affecting the traffic efficiency and also has certain guiding significance for the development of intelligent vehicles.

At present, about 40% of the fuel energy is discharged into air with the exhaust gas when an automobile is working, which is a big waste of energy. A thermoelectric generator (TEG) has the ability to harvest the waste heat energy in the exhaust gas. The traditional TEG cold-end is cooled by the engine cooling system, and although its structure is compact, the TEG weight and the space occupied are important factors restricting its application. In this paper, under the premise of ensuring the TEG maximum net output power and reducing the TEG water consumption as much as possible, the optimization of the TEG water thickness in the normal direction of the cold-end surface (WTNCS) is studied, which results in lighter weight, less space occupied and better automobile fuel economy. First, the thermal characteristics of the target diesel vehicle exhaust gas are evaluated based on the experimental data. Then, according to the thermoelectric generation model and the cold-end heat transfer model, the effect of the WTNCS on the cold-end temperature control stability and the system flow resistance are studied. The results show that the WTNCS influences the TEG cold-end temperature. When the engine works in a stable condition, the cold-end temperature decreases with the decrease of the WTNCS. The optimal value of the WTNCS is 0.02 m and the TEG water consumption is 8.8 L. Comparin it with the traditional vehicle exhaust TEG structure, the power generation increased slightly, but the water consumption decreased by about 39.5%, which can save fuel at0.18 L/h when the vehicle works at the speed of 60 km/h.

An ORC (Organic Rankine Cycle) system driven by hydraulic retarder waste heat oil source is investigated in this study. The main purpose is to identify the appropriate organic working fluid in consideration of the thermodynamic properties and evaporator dimension requirements. In addition, six working fluids including dry and isentropic fluid are used as the candidates in this article. Based on a specified condition, thermal efficiency and expansion ratio flexibility in the operating condition of a wide evaporating pressure and condensing temperature range, exergy efficiency and exergy destruction rate, evaporator heat transfer, and evaporator heat transfer area are chosen as the evaluation criteria to select the optimal working fluid. The results indicate that R245ca, R265mfc, and R123 occupy a larger coverage area as for the high thermal efficiency region, meaning that the operating conditions are more flexible for these fluids in the real vehicle application. Also, a same behavior is presented by the expansion ratio results. Besides, the evaporator heat transfer areas for R245fa and R245ca are the smallest, the maximum areas for which are just 2.59 m2 and 3.22 m2, respectively. Consequently, the optimal working fluid for the hydraulic retarder ORC system turns out to be R245ca. © 2016 American Institute of Chemical Engineers Environ Prog, 2016

Engine exhaust can be used by thermoelectric generators for improving thermal efficiency of internal combustion engines. In his paper, the performance of a thermoelectric evaporation system is investigated. First, the thermal characteristics of diesel engines are obtained according to the experiment data. Then, mathematical models are created based on the specified conditions of the coolant cycle and the evaporator geometric parameters. Finally, the heat transfer characteristics and power performance of the thermoelectric evaporation system are estimated, and a comparison with the system in which the heat exchanger operates with all-liquid coolant is investigated. The results show that the overall heat transfer rate of the thermoelectric evaporator system increases with engine power. At the rated condition, the two-phase zone with an area of 0.8689 m2 dominates the evaporator’s heat transfer area compared with the preheated zone area of 0.0055 m2, and for the thermoelectric module, the cold-side temperature is stable at 74°C while the hot-side temperature drops from 341.8°C to 304.9°C along the exhaust direction. For certain thermoelectric cells, the temperature difference between the cold side and hot side rises with the engine load, and the temperature difference drops from 266.9°C to 230.6°C along the exhaust direction. For two cold-side systems with the same heat transfer, coolant mass flow rate in the evaporator with two-phase state is much less, and the temperature difference along with equivalent heat transfer length L is significantly larger than in the all-liquid one. At rated power point, power generated by thermoelectric cells in the two-phase evaporation system is 508.4 W, while the other is only 328.8 W.

Eddy current brake (ECB) is an attractive contactless brake whereas it suffers from braking torque attenuation when the rotating speed increases. To stabilize the ECB’s torque generation property, this paper introduces the concept of anti-magneto-motive force to develop the ECB model on the fundamental of magnetic circles. In the developed model, the eddy current demagnetization and the influence of temperature which make the braking torque attenuation are clearly presented. Using the developed model of ECB, the external and internal characteristics of the ECB are simulated through programming byMATLAB. To find the sensibility of the influences on ECB’s torque generation stability, the stability indexes are defined and followed by a sensibility analysis on the internal parameters of an ECB. Finally, this paper indicates that (i) the stability of ECB’s torque generating property could be enhanced by obtaining the optimal combination of “demagnetization speed point and the nominal maximum braking torque.” (ii) The most remarkable influencing factor on the shifting the demagnetization speed point of ECB was the thickness of the air-gap. (iii) The radius of pole shoe’s cross section area and the distance from the pole shoe center to the rotation center are both the most significant influences on the nominal maximum braking torque.