Advanced Materials Research Vols. 724-725

Abstract: To investigate the idle performance of a HCNG with high hydrogen blend ratios, the effects of different excess air ratios (λ) and different hydrogen blend ratios on combustion, indicated thermal efficiency (ITE) and emissions of a 6-cylinder CNG engine were investigated. The results show that, with the increase of hydrogen blend ratio, rather high ITE can be achieved in a much wider range of λ. Under conditions of λ=1.2~1.4, emissions of CH₄, NMHC and CO are relatively low for different hydrogen blend ratios. When the hydrogen blend ratio is greater than 75%, emissions of CH₄, HMHC and CO increase only slightly with the increase of λ. NO_x emissions increase with the increase of hydrogen blend ratio. And these emissions reach their peaks for different hydrogen blend ratios under the conditions of λ=1.1-1.2.

Abstract: Based on the linear engine prototype designed by the studying team, the combustion characteristic of the linear engine in certain revolution is investigated experimentally. The effect of ignition timing and excess air ratio on combustion characteristic of the linear engine is studied based on cycle-by-cycle control technique. The result shows that the ignition timing has effect on the combustion characteristic of linear engines in certain revolution. Advancing the ignition timing from 1.0mm BTDC (before the top dead center) to 3.0mm BTDC, the peak cylinder pressure increases, the interval between peak cylinder pressure timing and the top dead center reduces, the IMEP (indicated mean effective pressure) is down, the instantaneous heat release rises and the total heat release decreases. The excess air ratio has apparently effect on combustion characteristic of linear engines in certain revolution. Reducing the excess air ratio from 1.45 to 1.35, the peak cylinder pressure increases, the peak cylinder pressure timing is closer to the top dead center, the instantaneous heat release and the total heat release are larger.

Abstract: Large-scale adoption of electric vehicles may impose impact on grid. In order to formulate the appropriate scheme of time-of-use (TOU) to lower the adverse effect of charging load on the power grid, it is necessary to analyze the impact of the peak-valley period partition on the load curve of distribution system with electric vehicles. The electric vehicle charging load model considering TOU was built according to the statistics of the driving habits. Several scenarios were set according to different period partitions and the changes of the load at start time of valley period, numerical value and moment of peak load and peak-valley differences were analyzed with the Monte Carlo simulation method under those scenarios. The simulation results show that the farther between the time instant of peak load and start moment of valley period the less impact it has on load curve of distribution system.

Abstract: The visualization experimental setup of micro free-piston engine has been built, the process of single shot compression combustion in micro combustion chamber has been observed by the high-speed digital camera; Based on the propane combustion kinetics, the numerical calculation method for combustion process coupling with the free-piston movement was put forward, through editing the dynamic mesh subroutine in STAR-CD, the process of homogeneous charge compression ignition (HCCI) in the micro chamber was studied; The influence of piston initial state on HCCI combustion process was analyzed , indicating that the piston mass directly affects the homogeneous gas compression ratio, ignition time, single combustion process cycle and the changes of combustion pressure and temperature, all this research can be the basic theories for designing the micro free piston engine .

Abstract: In order to determine the layout of electric car charging stations, a model for optimizing charging stations location is developed after charging-demand districts are divided, the number of electric vehicles and the center of each charging district are ready. This model takes the minimization of electric vehicles charging stations total cost which includes initial fixed investment costs, operating costs and charging costs as the objective function, some related constraints which include service radius, capacity of charging station etc. are considered. Particle swarm optimization based on hybridization is proposed to solve this problem. The example verifies feasibility of this method.

Abstract: In this paper, a method of magnetoelectricity power generation system for vehicle on the downhill of expressways is proposed. This system is a clean energy system that can be reused. Its structure includes car magnetic poles, magnetic poles imbedded in road surface, closed circuit imbedded in road surface, rectifier, inverter and storage battery. Multi-unit magnetic poles and closed circuits imbedded in the road surface are used in this invention, so when the car poles move with the running down of cars on downhill, magnetic flow in closed circuits will change to produce a technique of group control power generation. From the simulated system in the test, it can be seen that it is efficient and effective in generating power.

Abstract: Applied to an electric car, the battery frame structure was designed for the storage batteries of electric vehicles under the test conditions in accordance with the GB11551-2003 regulations, and the crashworthiness finite element analysis was conducted with ANSYS/LA-DYNA through which the deformation of the battery frame is observed. Under the premise of ensuring the storage battery is not disconnected from the shackles and fled into the crew cabin, the structure is optimized, and safety of the battery protection device is evaluated. Combining with the safety test program and finishing lightweight optimization design.

Abstract: To study Zn-PANi (polyaniline) battery dynamic characteristics a vehicle power supply based on miniature electric vehicles was designed. And the power battery dynamic test cycle was determined according to the vehicle test cycle prescribed under GB using Land battery testing system. The power battery steady characteristics tests include battery voltage test, per gram capacity test, self-discharge rate test, open circuit voltage and impedance test, cycle life test and short circuit test. Battery discharge characteristics include the relationship between discharge voltage and time, DOD(depth of discharge), the relationship between open circuit voltage, impedance and SOC in different discharge currents. Rationalization proposals in using Zn-PANi batteries efficiently by analyzing battery characteristics, advantages and disadvantages as power batteries are put forward.

Abstract: To analyze the economic benefit of electric taxi in two different models: battery charging model (ETC) and swapping model (ETS), this paper built total ownership cost model based on purchase and used cost, and equaled the total ownership cost of electric and conventional taxi in the nominal lifetime to get the maximum affordable battery charging price and battery swapping price respectively, which is 1.1 RMB yuan/kWh and 0.54 RMB yuan/km. The results show that ETS has economic advantage over ETC. Adjust the charging and swapping price to 0 RMB yuan, the equilibrium year of ETS is only 0.8 years, compared to ETCs 2.8 years.

Abstract: As the global shortage of oil resource and the rapid increase in car ownership, using gas as the alternative fuel is getting more and more important. Gas fuel, such as LNG (liquefied natural gas), with resource-rich, less pollution and other features, is desirable alternative fuels for cars. In this article, through the engine bench test, a comparative analysis of power performance, fuel economy, emission between diesel/LNG dual engine and diesel engine was done. The result shows that, compared to the original machine , power performance of modified diesel / LNG dual fuel engine decline but isnt obvious. At the same time , fuel economy has a substantial increase. The use of natural gas can relieve shortage of global oil resource and the supply-demand imbalance of oil products. The emission of modified diesel / LNG dual fuel engine has a better state than that of original machines. This kind of modified dual fuel engine is simple, low cost, easily promoted and will be well utilized in future.