Search

In view of the requirements of the special structural features of a series-parallel hybrid electric bus on its control strategy, an optimization simulation on its energy management strategy, which determines the power distribution between engine and battery, is conducted by using Pontryagin's minimum principle and based on the solution flow chart designed and the simulation model built, with battery power as control variable and minimizing fuel consumption as objective. The results demonstrate the marked effects of optimization on energy management strategy based on Pontryagin's minimum principle with the fuel consumption per 100km 18. 33% lower than that with rule-based control strategy. [ABSTRACT FROM AUTHOR]

Aiming at the effects of many factors such as uncertain driving environment and different driver's styles on the fuel economy of novel series-parallel hybrid electric bus (SPHEB) in real world driving conditions, a Markov model for driver's required power is built based on statistical data of several city driving cycles, and an energy management strategy based on stochastic dynamic programming (SDP) algorithm is proposed and the control rules for power distribution between engine and battery are obtained. Both the results of simulation on the forward model for novel SPHEB and hardware-in-the-loop test demonstrate that the proposed strategy enables the battery SOC to keep balance within its preset range and makes the engine operate in high efficiency region. In addition the fuel consumption per 100km of novel SPHEB reduces by 30.17% and 11. 29% respectively compared with original bus and that with rule-based strategy. [ABSTRACT FROM AUTHOR]

In order to solve the current problems about environmental pollution of agricultural waste and explore the technology of producing organic fertilizer by composting with pig manure and edible fungi residue, an experiment was conducted to study dynamic changes of several parameters including heat, pH value, organic carbon (C), germination index (GI), nutrient nitrogen (N), phosphorus (P) and potassium (K) during the natural fermentation. The experiment was based on the four ratios of 9:1, 8:2, 7:3 and 6:4 of pig manure and edible fungi residue in high-temperature composting experiment. The results showed as followed. The temperatures of all disposals were over 50 degrees centigrade at about the 3rd day. It maintained a high temperature for from 25 to 32 d, and then began to decrease. Duration of the high-temperature composting was longer while the ratio of the mushroom residue got more. From the experiment, we could see that the high-temperature duration of the disposal with the ratio of 6:4 was 7 d longer than the disposal with the ratio of 9:1. The pH values of all disposals, ranging from 6.83 to 8.62, increased rapidly and then decreased smoothly in the 22 d. Total N of the nutrient decreased with the loss of ammonia in the early, and then the relative quality of the total N began to rise while the total mass was reducing along with the loss of C content. At the end of the composting, the total N contents of the disposals A and B decreased by 2.9 and 1.0 g/kg, respectively, but the disposals C and D increased by 1.6 and 1.9 g/kg, respectively. The total P and total K contents have been on a slow upward trend, until the end of the composting they increased by 14.2%-36.4% and 28.1%-34.7% respectively. The organic C content decreased in general. At the end of the composting, the organic C contents of all disposals respectively decreased by 16.3%, 14.5%, 13.6% and 11.9%. Due to the rich source of N in the early time, microbes multiplied and let out large-scale ammonia N, which resulted in the rapid increase in the C/N ratio, and then the average ratio declined; and the 4 disposals decreased by 0.67, 2.08, 4.48 and 4.49 respectively in the end. Except the disposal with the ratio of 6:4, the GI of all disposals respectively reached 80% on the 23rd, 33rd, 47th day. At the same time, the toxicity of the piles extract liquid increased on plants due to the accretion of the ratio of fungi residue. The total nutrient contents of N, P and K were in a flat or a small decline and then continued to rise in the early period (in about 19 d), which were respectively 5.93%, 5.57%, 5.64% and 5.13% for all disposals at the end of the composting. In addition, the disposal with the ratio of 6:4 was less than 5% in the most period of the composting (within 45 d), but the rest disposals were more than 5% after about 21-25 d. Considering the factors of the compost quality and production cycle comprehensively, the appropriate ratio of manure to mushroom residue is 8:2 for making scale production of organic fertilizer. Furthermore, on account of the low C/N ratio of manure and mushroom residue, it is better to add some annexing agent with high C/N ratio such as rice bran for improving the efficiency of composting. [ABSTRACT FROM AUTHOR]

A three-dimensional heat dissipation model is built for the lithium-ion battery pack in an electric vehicle. Both simulation and test are conducted on the temperature field of lithium-ion battery pack in a condition of cruise driving and natural air cooling with a result showing their consistency in temperature variation trend, meaning the rationality of the model built. On this basis an optimization scheme for the heat dissipation structure of lithium-ion battery pack is proposed and a simulation is performed. The results indicate that after optimization, lithium-ion battery pack has a good cooling effects: the highest temperature of battery pack lowers from 46°C to 33°C and the temperature difference among the batteries is less than 6°C. [ABSTRACT FROM AUTHOR]