Current Issue : January - March Volume : 2017 Issue Number : 1 Articles : 5 Articles
The collection of clean power from ambient vibrations is considered a promising method for\nenergy harvesting. For the case of wheel rotation, the present study investigates the effectiveness of\na piezoelectric energy harvester, with the application of stochastic resonance to optimize the efficiency\nof energy harvesting. It is hypothesized that when the wheel rotates at variable speeds, the energy\nharvester is subjected to on-road noise as ambient excitations and a tangentially acting gravity force\nas a periodic modulation force, which can stimulate stochastic resonance. The energy harvester\nwas miniaturized with a bistable cantilever structure, and the on-road noise was measured for the\nimplementation of a vibrator in an experimental setting. A validation experiment revealed that the\nharvesting system was optimized to capture power that was approximately 12 times that captured\nunder only on-road noise excitation and 50 times that captured under only the periodic gravity force.\nMoreover, the investigation of up-sweep excitations with increasing rotational frequency confirmed\nthat stochastic resonance is effective in optimizing the performance of the energy harvester, with\na certain bandwidth of vehicle speeds. An actual-vehicle experiment validates that the prototype\nharvester using stochastic resonance is capable of improving power generation performance for\npractical tire application....
This article is devoted to the identification of traction and speed characteristics as\nwell as of fuel economy of motor vehicles in road conditions. Among common variants of\nmeasuring of the above stated values, the preference was given to the immediate gaining of\nfactors by means of a computer-aided measuring system. There is a theoretical justification\ngiven to the suggested approach as well as methods and results allowing to provide a\npractically sufficient solution accuracy of the problem....
A novel kinetic dynamic suspension (KDS) system is presented for the cooperative control of the roll and warp motion modes of\noff-road vehicles. The proposed KDS system consists of two hydraulic cylinders acting on the antiroll bars. Hence, the antiroll bars\nare not completely replaced by the hydraulic system, but both systems are installed. In this paper, the vibration analysis in terms\nof natural frequencies of different motion modes in frequency domain for an off-road vehicle equipped with different configurable\nsuspension systems is studied by using the modal analysis method.Thedynamic responses of the vehicle with different configurable\nsuspension systems are investigated under different road excitations and maneuvers.The results of themodal and dynamic analysis\nprove that the KDS system can reduce the roll and articulation motions of the off-road vehicle without adding extra bounce stiffness\nand deteriorating the ride comfort. Furthermore, the roll stiffness is increased and thewarp stiffness is decreased by the KDS system,\nwhich could significantly enhance handing performance and off-road capability....
This paper investigates the performance and emission characteristics of HCCI engines fueled with\noxygenated fuels (ethanol blend). A modeling study was conducted to investigate the impact of ethanol addition on\nthe performance, combustion and emission characteristics of a Homogeneous Charge Compression Ignition (HCCI)\nengine fueled by diesel. One dimensional simulation was conducted using the renowned commercial software for\ndiesel and its blend fuels with 5% (E5) and 10% ethanol (E10) (in vol.) under full load condition at variable engine\nspeed ranging from 1000 to 2750 rpm with 250 rpm increment. The model was then validated with other researcher�s\nexperimental result. Model consists of intake and exhaust systems, cylinder, head, valves and port geometries.\nPerformance tests were conducted for volumetric efficiency, brake engine torque, brake power, brake mean effective\npressure, brake specific fuel consumption, and brake thermal efficiency, while exhaust emissions were analyzed for\ncarbon monoxide (CO) and unburned hydrocarbons (HC. The results showed that blending diesel with ethanol\nincreases the volumetric efficiency, brake specific fuel consumption and brake thermal efficiency, while it decreases\nbrake engine torque, brake power and brake mean effective pressure. In term of emission characteristics, the CO\nemissions concentrations in the engine exhaust decrease significantly with ethanol as additive. But for HC emission,\nits concentration increase when apply in high engine speed. In conclusion, using Ethanol as fuel additive blend with\nDiesel operating in HCCI shows a good result in term of performance and emission in low speed but not\nrecommended to use in high speed engine. Ethanol-diesel blends need to researched more to make it commercially\nuseable....
Severe low-temperature conditions, in which considerable part of Russian Motor\nPark is operated, affect vehicles negatively. Cold weather causes higher fuel consumption and\nCO2 emissions always. It is because of temperature profile changing of automobile motors,\nother systems and materials. For enhancement of car operation efficiency in severe winter\nenvironment the dependency of engine warm-up and cooling time on ambient air temperature\nand wind speed described by multifactorial mathematical models is established. -On the basis\nof experimental research it was proved that the coolant temperature constitutes the engine\nrepresentative temperature and may be used as representative temperature of engine at large.\nThe model of generation of integrated index for vehicle adaptability to winter operating\nconditions by temperature profile of engines was developed. the method for evaluation of\nvehicle adaptability to winter operating conditions by temperature profile of engines allows to\ndecrease higher fuel consumption in cold climate....
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