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The paper reports an experimental and simulating exploration over a series of problems such as overheat of the complete machine and thermal cracks in the valve bridge region of cylinder head. The studies involve heat load test of complete machine, measuring the temperature of the bottom part of cylinder head, analyzing coolant-flow distribution of upper nozzles in the bottom side of cylinder head, and three-dimensional numerical simulation on the coolant flow in the sixth cylinder water jacket which lies on the most wicked heat transfer condition. The test and simulation results show that overheat of engine results largely from insufficiency of the heat-sinking capacity of water-radiator and shortage of the coolant flux. The unsuitable flow field in cylinder head water jacket, where only 12.22% coolant can cool the bottom of cylinder head, is the main reason causing cylinder head overheat on the bottom side and thermal cracks in the valve bridge region.

Problems such as higher heat load in the diesel engine and the occurrence of crazes within the valve bridge of heavy-duty vehicle diesel engine should be solved, with the increase of the power density of heavy-duty vehicle diesel engine. In this paper, the heat load experiment of complete machine, temperature-measuring of bottom part of cylinder head and the three-dimension numerical simulation on coolant flow and heat transfer in the water jacket have been performed. The result shows that the main reasons of higher heat load of the engine are insufficiency of heat-sinking capability of the water-radiator and shortage of coolant flux; and the unsuitable flow field in water jacket in cylinder head, where only a little of the coolant can cool the bottom of cylinder head, is the main cause of cylinder head bottom over-heated and thermal crack in the valve-bridge region.

Faced with the need to reduce development time and cost, the hardware-in-the-loop simulation increasingly proves to be an efficient tool in the development of automotive engine control system. In this article, the rapid prototyping technology is used to develop a hardware-in-the-loop simulation system for the diesel engine electronic control unit development. The hardware-in-the-loop simulation presented in this paper is based on Linux RTAI system, an open source hard real-time extension of the Linux Operating System, at low costs and within industrial standards. It exploits standard x86-based computing platforms provided with real-time Linux software in combination with generic computer-aided design software (Matlab/Simulink). One of its main characteristics is that it can automatically generate the real-time simulation code for many target processors, which runs under Linux RTAI operating system.

A zero-dimensional, thermodynamic model with detailed chemical kinetics and cylinder wall heat transfer correlations has been used to study the detailed oxidation mechanism of natural gas in homogeneous charge compression ignition (HCCI) engine. A short mechanism made up of 241 reversible elementary reactions among 47species has been assembled from a previously extended detailed mechanism. The mechanism was numerically investigated at different operating and geometry conditions of HCCI engine during the time period in which both intake and exhaust valves are closed. The study is performed to elucidate the mechanisms of extinction and combustion behaviors of natural gas fuel with the effect of hydrogen addition to overcome the control of autoignition timing over a wide range of speeds and loads, limiting the heat released rate at high load operation, and meeting emission standards.

In this paper, a quasi-dimensional multi-zone spray combustion model is developed to simulate the combustion and emission of direct injection engine fueled with dimethyl ether (DME). The analysis of the spray mixing process is based on a quasi-dimensional gas jet model which consists of integral continuity and momentum equations. The heterogeneous field of temperature and temporal distribution histories of fuel in the combustion chamber is considered by dividing the chamber into n-zones. The jet mixing models are used to determine the amount of fuel and entrained air in each zone available for combustion. The mass, energy and state equations are applied in each zone and the combustion process is controlled by chemical reactions which are calculated by adopting CHEMKIN code. The CHEMKIN libraries have been used to formulate a stiff chemical kinetic solver suitable for integration within the engine cycle simulation.

Transient heat transfer computer program of the coupling 3-D moving piston assembly-lubricant film-liner system is successfully developed for predicting the distribution of temperatures in the component system, in which the finite element technology has been employed. The heat transfer relation of the moving piston assembly-lubricant film-liner has been established and 3-D discrete model of the system is obtained with the hypothesis of thinking the lubricant film as 1-D heat resistance. The discrete models of single component are assembled into the whole coupling model with the coupling theory. Some appropriate ways have been employed to deal with the moving arrays in the stiffness matrix because of the moving boundary conditions. The software has been employed to analyze a gasoline engine.

Three constitutive models which capture the amplitude and frequency dependency of filled elastomers are implemented for the conventional engine mounts of automotive powertrain mounting system (PMS). Firstly, a multibody dynamic model of a light duty truck is proposed, which includes 6 degrees of freedom (DOFs) for the PMS. Secondly, Three constitutive models for filled elastomers are implemented for the engine mounts of the PMS, including: (1) Model 1: Kelvin-Voigt model; (2) Model 2: Fractional derivative Kelvin-Voigt model combined with Berg’s friction; (3) Model 3: Generalized elastic viscoelastic elastoplastic model. The nonlinear behaviors of dynamic stiffness and damping of the mounts are investigated. Thirdly, simulations of engine vibration dynamics are presented and compared with these models and the differences between common Kelvin-Voigt model and other constitutive models are observed and analyzed.

In this work, a XD132 Road Roller from XCMG in China was employed as a research basis to study the heat exchange performance of the heat dissipation module under varied working conditions. The module in the XD132 consists of a cooling fan and three radiators. At first, the numerical investigation on the elementary units of radiators was performed to obtain Colburn j factor and Fanning friction f factor, which were used for the ε-NTU method to predict the radiator performance. The fan was numerically tested in a wind test tunnel to acquire the performance curve. The performance data from both investigations were transformed into the boundary conditions of the numerical vehicle model in a virtual tunnel. A field experiment was carried out to validate the simulation accuracy, and an entrance coefficient was proposed to discuss the performance regularity under four working conditions.

The sewing machine has been widely used in various aspects of life and it is essential to study its kinematic and dynamic characteristics. A dynamic model of flexible multi-link mechanism for sewing machine including joints with clearance is established to analysis its dynamic response in the present work. The configuration of the sewing machine mainly included five subsystems, feeding mechanism, needle bar mechanism, looper mechanism, shearing mechanism and adjusting mechanism. Since the sewing machine mainly consist of linkage mechanisms that are connected by revolute joints and translational joints, the existence of clearances in the joints and the flexibility of crankshafts and linkage are important factors that affect the dynamic performance. Even little clearance can lead to vibration and fatigue phenomena, lack of precision or even make overall behavior as random.

In this study, a measurement system is developed for obtaining continuous piston temperatures in a working engine by using a voltage recorder. The developed system has a very high accuracy with a measurement error within ± 1 °C. Since there is no relative movement between the measurement system and the piston, its reliability significantly increases. In order to test its accuracy and reliability, the developed measurement system is used to obtain the piston temperatures under various operating conditions with different air-fuel ratios, oil temperatures, and engine speeds. The measurement results are then used to calibrate the piston temperature field simulated by numerical analysis.

Construction vehicles own some inherent characteristics, such as low velocity, high power and following heavy heat flux et al. Aiming at decreasing flow resistance and managing airflow, a 39 ton single drum road roller from one of the biggest manufactures in China was employed as a research target to seek out the effect of air flow resistance on the performance of its heat dissipation system. For a start, a simplified 3D model of the road roller in a virtual wind tunnel was established with a commercial software, which was pre-processed in Gambit later. The radiators were set with heat exchanger boundary condition based on the analysis on the air-side elementary unit, as for the cooling fan, the experimental results in the wind tunnel were transformed into the corresponding boundary condition.

Free vibration of the blades of one radial-flow turbocharger is analyzed by the finite element method, and the natural frequencies and modes are obtained, the numerical results are in good agreement with the experimental ones. Resonant vibration of the compressor blade and turbine blade is analyzed respectively, then the resonance interference analysis of the blades is presented, the resonance occurrence probabilities of the blades at the rotating operation speed of the turbocharger is obtained, finally the working reliability of the blades is evaluated.

Intelligent vehicle-to-everything connectivity is an important development trend in the automotive industry. Among various active safety systems, Autonomous Emergency Braking (AEB) has garnered widespread attention due to its outstanding performance in reducing traffic accidents. AEB effectively avoids or mitigates vehicle collisions through automatic braking, making it a crucial technology in autonomous driving. However, the majority of current AEB safety models exhibit limitations in braking modes and fail to fully consider the overall vehicle stability during braking. To address these issues, this paper proposes an improved AEB control system based on a risk factor (AERF). The upper-level controller introduces the risk factor (RF) and proposes a multi-stage warning/braking control strategy based on preceding vehicle dynamic characteristics, while also calculating the desired acceleration.