Search Results

Increasing energy costs justify research on how to improve utilization of low-grade energy that is abundantly available as waste heat from many thermodynamic processes such as internal combustion engine cycles. One option is to directly generate cooling through absorption/adsorption or vapor jet ejector cycles. As in the case of power generation cycles, cooling cycle efficiencies would increase if the heat input were available at higher temperature. This paper assesses the feasibility of a novel idea that uses a vortex tube to increase the available temperature levels of low-grade heat sources. The desired temperature increase is achieved by sending a stream of vapor that was heated by the waste heat source through a vortex tube, which further elevates the temperature used in a heat driven ejector cooling cycle.

Several types of noise exist in automobiles. The flow-induced noise in the expansion device can be very disturbing since the expansion device is located near the occupants. In many studies, the flow-induced noise is found to be mitigated when the orientation of the tube is changed. However, no study explores the reason why flow-induced noise changes when the orientation of the tube is changed. The flow-induced noise varies along with the flow regimes near the expansion devices. In this paper, an experimental based research is used to study how the tube orientation changes the flow regimes under the same operating conditions. A pumped R134a system with transparent tubes (1/4-inch ID) is used to visualize the flow regimes near the manual expansion valve. The transparent tube is a continuous connection of horizontal tubes, 45° inclined tubes, and vertical tubes.

In the process of truck overload and over-limit detection, it is necessary to detect the characteristics of the vehicle's size, type, and wheel number. In addition, in some vehicle vision-based load recognition systems, the vehicle load can be calculated by detecting the vibration frequency of specific parts of the vehicle or the change in the length of the suspension during the vehicle's forward process. Therefore, it is essential to quickly and accurately identify vehicle features through the camera. This paper proposes a vehicle feature recognition method based on image semantic segmentation and Python, which can identify the length, height, number of wheels and vibration frequency at specific parts of the vehicle based on the vehicle driving video captured by the roadside camera.

An overview of enrollment trends and curricular changes in engineering education in the past ten years. Comments are made about the implications of lower enrollment on quality of education and availability of engineers for the employment market. Discussions of curricular variations summarizes changes such as computerization of engineering studies, expansion of high school preparation, and selection of major studies for students.

The hydraulic retarder is an auxiliary braking device generally equipped on commercial vehicles. Its oil temperature change influences the brake performance of hydraulic retarder. The Organic Rankine Cycle (ORC) is a good means to recover exhausted heat. Moreover, it can cool oil and stably control oil temperature with the help of heat absorption related with evaporation. Comprehensively considering the heat-producing characteristics of hydraulic retarder and the temperature control demand, the aimed boundary conditions are determined. Also the changing rules about the working medium flow rate are obtained. In this work, the heat-producing properties of hydraulic retarder under different conditions and the oil external circulating performance is firstly analyzed. By researching the system’s adaptation to the limiting conditions, the aimed temperature to control is prescribed.

The control forms of the vehicle have transformed from hydraulic or mechanical control to electrical control owing to the increasing demand of automotive safety and soaring development of electronic technology. Compared with the traditional mechanical parking brake system, the electrical control of brake named Electrical Parking Brake (EPB) System presents a variety of advantages. What's more, it shares common actuators and realizes the communication between electrical control systems to advance the vehicle industry to intellectualization. With such superiority, the EPB System has aroused much interest. But the difficulty in building the simulation model lies in the description of friction in screw-nut system of which the nonlinear component causes the hysteresis. However, almost all models found in the literature before are the static friction model with the limit of description of dynamic features like pre-sliding frictional features and parameters variation.

Automotive Front Lighting System(AFS) can receive the steering signal and the vehicular speed signal to adjust the position of headlamps automatically. AFS will provide drivers more information of front road to protect drivers safe when driving at night. AFS works when there is a steering signal input. However, drivers often need the front road's information before they turn the steering wheel when vehicles are going to go through a sharp corner, AFS will not work in such a situation. This paper studied how to optimize the working time of AFS based on GIS (Geographic Information System) and GPS(Geographic Information System) to solve the problem. This paper analyzed the process of the vehicle is about to go through a corner. Low beams and high beams were discussed respectively.

The hydraulic retarder, which is an auxiliary brake device for enhancing traffic safety, has been widely used in kinds of heavy commercial vehicles. When the vehicle equipped with the retarder is traveling in non-braking state, the transmission loss would be caused because of the stirring air between working wheels of the rotor and the stator no matter if the retarder connects in parallel or in series with the transmission [1]. This paper introduces an elaborate hydraulic retarder air-friction reduction system (AFRS) which consists of a vacuum generating module and pneumatic control module. AFRS works to reduce the air friction by decreasing the gas density between working wheels when the retarder is in non-braking state. The pneumatic control model of hydraulic retarder is built first. Then various driving conditions are considered to verify the performance of the AFRS. The stability of the AFRS is analyzed based on the complete driveline model.

The Organic Rankine Cycle System is an effective approach for recovering the engine exhaust thermal energy. The physical characteristic of the Rankine fluid is the key factor for the capacity and the stability of the expander power output. In the research, the influences of the evaporator organic medium state and flow rate on the expander power output are fully analyzed for the sufficient utilization of the waste thermal energy. Firstly, the exhaust characteristics of the diesel engine were processed by the data of the bench test. Then, the integral mathematical model of the Organic Rankine Cycle was built. Based on the comparison for the 2-zone and 3-zone evaporator, the influence for expander output are analyzed especially emphasis on the factors of engine working condition, the flow rate, temperature and state of Rankine fluid.

The automobile exhaust energy can be recovered by the thermoelectric module generator(TEG). Owing to the complex urban traffic, the exhaust gas’s temperature fluctuations are resulted, which means the unstable hot-end temperature of the TEG. By installing solid heat capacity material(SHCM) to the area between the outer wall of the exhaust pipe and the TEG, it is possible to appropriately reduce the temperature fluctuation, but there is still a fluctuation of the TEG’s power output. Then by adding voltage filter circuit (VFC) after the TEG, the power output stability can be improved. This research uses SHCM and VFC to improve the stability of the exhaust gas generation. Firstly, the three-dimensional heat transfer model of the exhaust pipe thermoelectric power generation system is established. The heat capacity materials with low thermal resistance and high heat capacity were selected as the research object based on previous research.

The paper reviews some of the underpinnings of the research that was done that led to adoption of the high mounted brake lamp. The expected reduction in rearend collisions of 50%, attributable to the lamp, has not been realized. Most recently, a reduction of 4% was reported. This large difference between the predicted effectiveness of the safety device with its actual effect is disturbing. The paper attempts to show the reasons for the low effectiveness which include a lack of evidence for the high-mounting location, overriding an SAE standard on the intensity of high-mounted rear signal lamps and no valid theory of driver performance.

In summer, when vehicle parks in direct sunlight, the closed cabin temperature would rise sharply, which affects the occupants step-in-car comfort Solar powered vehicle parking ventilation system adopts the solar energy to drive the original ventilator. Thus, the cabin temperature could be dramatically decreased and the riding comfort could be also improved. This research analyzed the modified crew cabin thermal transfer model. Then the performance of the solar powered ventilation system is analyzed and optimized combined with the power supply characteristics of the photovoltaic element. The storage and reuse of the solar power is achieved on condition that the cabin temperature could be steadily controlled. The research shows that, the internal temperature is mainly affected by the solar radiation intensity and the environment temperature.

Head-up Display (HUD) system can avoid drivers’ distraction on dashboard and effectively reduce collisions caused by emergency events, which is gradually being realized by researchers around the world. However, the current HUD only displays information like speed, fuel consumption, other information like acceleration and braking can’t be displayed yet. This research will use the indicator symbol‘s color and position change to remind drivers to brake or accelerate. Drivers can do driving operation timely and accurately. The system has the advantages of safety, intuition and real-time. The vehicle safe speed is calculated according to the road parameters, like adhesion coefficient and slope, and vehicle parameters, such as vehicle mass and centroid. Then, the appropriate braking operations are obtained by combining the vehicle driving state. The braking information is corresponded to the color and position change of the indicator symbol to prompt the drivers by the HUD interface.

With the development of the Internet for vehicles, the Car-sharing has been developed rapidly in recent years. This paper focuses on the network programming and distribution for Car-sharing, which helps to clarify the characteristics and basic law of Car-sharing network development, as well as the main approaches to construct it. Firstly, by analyzing the effect factors and expanding ways of Car-sharing network, characteristics of the development of Car-sharing industry and its network, as well as main Car-sharing users and services, the influence factors of Car-sharing demand and the main demand points in a city are summarized. Secondly, in order to better evaluate the network programming and distribution for Car-sharing, this paper proposes an optimization decision method of the car-sharing network planning by evaluating the possible alternatives in a same scale. The assessment index of Car-sharing network planning is constructed.

The mountain roads are curved and complicated, with undulating terrain and large distance between charging stations. Compared with traditional powered vehicles, in addition to safety issues, pure electric vehicles also need to deal with the driving range issue. At present, the relevant researches on automobile driving in mountainous areas mainly focus on the driving safety of traditional fuel oil vehicles when going uphill and downhill, while there are few researches on the driving planning of pure electric commercial vehicles on curved slope road. This paper presents a speed planning method for pure electric commercial vehicles based on vehicle-road collaboration technology. First, establish the vehicle dynamics model, analyze the vehicle dynamics characteristics when passing the downhill curve, calculate the safe speed range of the vehicle when passing the downhill curve, and establish the safe speed model of the downhill curve.

This research is based on the Controller Area Network (CAN) bus, and briefly analyzed its communication protocol with reference to the layered model of Open System Interconnect Reference Model (OSI). Subsequently, a data acquisition system was designed and developed including a Vehicle Communication Interface (VCI) and a laptop. After the overall architecture was built, the communication mechanism of the VCI was studied. Furthermore, the lap top app was built using the layered design followed by the implementation of a scheme for data collection and experimentation involving the test driving of a real car on road. Finally, the driving style was identified by means of fuzzy reasoning and solving ambiguity based on fuzzy theory; via training the acceleration sample and forecast using the excellent learning and generalization ability of Support Vector Machine (SVM) for high-dimensional, finite samples.

The turbine blade is a key component in the operation of the steam turbine hence the design and manufacturing level of the blade will directly affect the performance and efficiency of the turbine. CAD/CAM has been the foundation and important part of advanced manufacturing technology. It is important to study the steam turbine blade integrated CAD/CAM system to improve the design and manufacture of the blade. In this paper, the structure of CAD/CAM system for steam turbine blade is studied and the extensible framework structure including user layer, functional layer and system layer is proposed. Based on the control points of the turbine blade profile design method, and based on the expression between the three-dimensional parametric vector modeling method in UG-based platform, the use of UG/Open development tools and Visual C # developed a turbine blade CAD system.

Eddy current retarder (ECR) shares a large market of auxiliary brakes in China, but shortcomings of the short continuous braking time and the high additional energy consumption are also obvious. The propose of combined braking partakes the braking torque of ECR. However, the existed serial-parallel braking strategy could hardly balance well the relationship between the braking stability and the energy recovery efficiency. This research puts forward an energy management strategy of combined braking system which aims to maximize energy recovery while ensure the brake stability. The motor speed, the braking request and the state of charge (SoC) of the storage module are analyzed synthetically to calculate the reasonable braking torque distribution proportion. And the recovered energy is priority for using in the braking unit to reduce the additional energy consumption in this strategy.

As an auxiliary braking device of heavy-duty vehicle, eddy current retarder can reduce the brake failure due to the high temperature of the main brake. Nevertheless, the eddy current retarder will generate high temperature locally during the working process of it, leading to the decline of the brake power. The study on the heating characteristics of eddy current retarder is advantageous to the layout and parameter design of the liquid cooling channel of the retarder body and prolong the effective time of the auxiliary brake. In this research, a new kind of integrated eddy current retarder has been established. The thermal-magnetic coupling characteristics are studied and the laws of variation in torque output of auxiliary brake affected by the body temperature of retarder are analyzed. The boundary conditions are provided for the construction of the cooling channel. Firstly, the distribution of magnetic field and the characteristics of eddy current are simulated.

To study the mechanism of the effect of low-viscosity oils on engine friction loss reduction so as to improve the vehicle fuel economy of the Worldwide harmonized Light vehicles Test Cycle (WLTC) by upgrading the Society of Automotive Engineers (SAE) viscosity grade of the factory fill oil from 5W30 to 0W20, eight 0W20 oil samples were blended with different doses of base oil, viscosity modifier (VM), and friction modifier (FM). Theoretical analysis by AVL-EXCITE simulation of the key friction pairs combined with practical engine friction torque test and vehicle WLTC fuel consumption tests were carried out. The results showed that 0W20 oils can effectively reduce the engine friction torque by 5.64 Nm and the friction loss by 11.95% with the throttle fully opened; while with the throttle closed, the friction torque decreased by 3.53 Nm and the friction loss by 11.26%, resulting to the improvement of the vehicle WLTC fuel economy by 2.08%.