For the purpose of designing a reasonable control strategy for DOC-assisted DPF regeneration, a mathematical model that describes the thermal phenomenon both in a diesel oxidation catalyst (DOC) and diesel particulate filter (DPF) during regeneration is developed. All boundary conditions of this model are obtained by experiments. The effects of the main exhaust parameters such as exhaust mass flow rate, exhaust temperature, oxygen concentration and emission of reactants are investigated comprehensively. The effects of two main parameters of control strategy, DOC-out temperature and soot loading, are analyzed as well. To quantify the effects of relevant parameters, the fuzzy grey relational analysis method is utilized to evaluate the correlation coefficient of all factors to key indexes of DPF regeneration such as maximum temperature, maximum rate of temperature increase and regeneration duration. The results of this work will greatly reduce the complexity of analysis and enable more rational control strategy design of DOC–DPF regeneration systems.

Parabolic dish solar concentrators are currently one of the most efficient solar technologies for the production of electricity. These systems are usually located in an open terrain where strong winds may be found and could affect their stability and optical performance. Mirror gap size has direct relation to thermal efficiency and construction cost. A tiny deformation of the concentrator under the action of a strong wind affects the focusing accuracy and increases the requirement of the structural strength of the dish. In this paper, different gap sizes (0–60 mm) between the mirrors of the dish are studied by numerical simulation. The results show that wind load on concentrator is sensitive to operation position, such as 30° pitch and 60° yaw angle. The gap causes an uneven distribution of the mean pressure coefficient on each facet, thereby increasing the risk of wind-induced vibration at the mirror edge. Besides, the drag coefficient on a parabolic dish increases along with the increase of the gap size between 0 and 60 mm when the dish is at the wind-resistant unfavorable conditions. For the overall wind force on a dish in the state of maximum drag force operation angle case, the mirror gap can reduce the wind force by about 3.54% with the gap size increased, which is mainly due to the significant reduction of the windward area. Therefore, the mirror gap should take as small a size as possible.

The back-pressure gradually rises with the increasing particulate sediment during the diesel particulate filter (DPF) working. it will be harmful to the fuel economy of diesel engine. In order to keep the good fuel economy, when the back-pressure exceeds the set threshold-value, the sediment particulate must be cleaned in DPF namely regeneration, therefore, the exhaust back-pressure threshold-value for every working condition is pivotal to the DPF regeneration time. Taking the burner-type DPF as an example, through the real-time measure data of the diesel engine rotate speed, load, corresponding fuel consumption and DPF exhaust back-pressure, with the data processing method and the diesel engine fuel consumption ratio mode based on the multiple regression theory, taking advantage of MATLAB mighty function in mathematic operation and figure disposal, the fuel consumption characteristic map of the diesel engine equipped with DPF is plotted. Further, with the above corresponding test data, the DPF regeneration MAP of exhaust back-pressure threshold-value is obtained.