MODELING AND IMPLEMENTATION OF SPEED GOVERNOR FOR THE HYBRID ELECTRIC VEHICLE ENGINE

A speed control analysis for an in-line gasoline fueled internal combustion （IC） engine is presented for the purpose of alleviation of high frequency oscillations in engine revolutions. A dynamic cylinder-by-cylinder model is proposed, base on slider-crank mechanism, which is extended to develop a digital governor providing a high fidelity estimation of rotary speed oscillation for hybrid vehicle engines. A modified PID controller that P and I gain is placed in feedback path is also described for hybrid electric vehicle （HEV） engine speed regulation, By comparison between measured and estimated signals, it is demonstrated that a good agreement has been achieved and the governor behaves an excellent damping speed ripple.

A New Hybrid Control Scheme for an Integrated Helicopter and Engine System

A new hybrid control scheme is presented with a robust multiple model fusion control（RMMFC） law for a UH-60 helicopter and an active disturbance rejection control（ADRC） controller for its engines.This scheme is a control design method with every subsystem designed separately but fully considering the couplings between them.With three subspaces with respect to forward flight velocity,a RMMFC is proposed to devise a four-loop reference signal tracing control for the helicopter,which escapes the closed-loop system from unstable state due to the extreme complexity of this integrated nonlinear system.The engines are controlled by the proposed ADRC decoupling controller,which fully takes advantage of a good compensation ability for unmodeled dynamics and extra disturbances,so as to compensate torque disturbance in power turbine speed loop.By simulating a forward acceleration flight task,the RMMFC for the helicopter is validated.It is apparent that the integrated helicopter and engine system（IHES） has much better dynamic performance under the new control scheme.Especially in the switching process,the large transient is significantly weakened,and smooth transition among candidate controllers is achieved.Over the entire simulation task,the droop of power turbine speed with the proposed ADRC controller is significantly slighter than with the conventional PID controller,and the response time of the former is much faster than the latter.By simulating a rapid climb and descent flight task,the results also show the feasibility for the application of the proposed multiple model fusion control.Although there is aggressive power demand in this maneuver,the droop of power turbine speed with an ADRC controller is smaller than using a PID controller.The control performance for helicopter and engine is enhanced by adopting this hybrid control scheme,and simulation results in other envelope state give proofs of robustness for this new scheme.

Numerical modelling of the hybrid rocket engine performance

The purpose of this paper is to present method of the numerical modeling of the hybrid rocket engine's work as a tool for designing engines of this type.The model is intended as an accurate and simple to use development tool for use in preliminary design stages of hybrid rocket engines,improving the effectiveness and quality of this process.General assumptions underlying the use of a model are presented,together with an analysis of past work in this field.Results of an extensive experimental campaign are presented and compared with the results of numerical modelling in order to calibrate the proposed model and evaluate its accuracy.Parameter variation and optimization were conducted,proving functionality of the methodology.Presented numerical calculations show that the adopted approach to reduce the analysis time and complexity was correct.This method of numerical calculation of hybrid engine working parameters combines aspects of accuracy and simplicity at the early design stage to avoid timeconsuming and costly changes in subsequent detailed stages of design.

用扣除杂交法分离藏红花苷合成相关基因的克隆

对藏红花苷合成的相关基因进行了初步分离与克隆实验研究,旨在分离与藏红花苷合成相关的特异性表达的cDNA克隆,为进一步从分子水平上研究藏红花素的合成机理奠定基础。实验采用经添加诱导子和合成前体、处于藏红花苷合成状态下的藏红花细胞和未添加诱导子和合成前体、处于生长状态的对照藏红花细胞为材料,采用扣除杂交法成功地分离到6条与藏红花苷合成相关的特异性表达的cDNA克隆。结果表明:其中一条与胡杨中由高盐环境引起的差异表达的一条mRNA的序列有较高的同源性。

Surface Doping vs.Bulk Doping of Cathode Materials for Lithium-Ion Batteries:A Review

To address the capacity degradation,voltage fading,structural instability and adverse interface reactions in cathode materi-als of lithium-ion batteries(LIBs),numerous modification strategies have been developed,mainly including coating and doping.In particular,the important strategy of doping(surface doping and bulk doping)has been considered an effective strategy to modulate the crystal lattice structure of cathode materials.However,special insights into the mechanisms and effectiveness of the doping strategy,especially comparisons between surface doping and bulk doping in cathode materials,are still lacking.In this review,recent significant progress in surface doping and bulk doping strategies is demonstrated in detail by focusing on their inherent differences as well as effects on the structural stability,lithium-ion(Li-ion)diffusion and electrochemical properties of cathode materials from the following mechanistic insights:preventing the exposure of reactive Ni on the surface,stabilizing the Li slabs,mitigating the migration of transition metal(TM)ions,alleviating unde-sired structural transformations and adverse interface issues,enlarging the Li interslab spacing,forming three-dimensional(3D)Li-ion diffusion channels,and providing more active sites for the charge-transfer process.Moreover,insights into the correlation between the mechanisms of hybrid surface engineering strategies(doping and coating)and their influences on the electrochemical performance of cathode materials are provided by emphasizing the stabilization of the Li slabs,the enhancement of the surface chemical stability,and the alleviation of TM ion migration.Furthermore,the existing challenges and future perspectives in this promising field are indicated.

Utilisation of turboelectric distribution propulsion in commercial aviation:A review on NASA's TeDP concept

Emissions produced by the aviation industry are currently a severe environmental threat;therefore,aviation agencies and governments have set emission targets and formulated plans to restrict emissions within the next decade.Hybrid aircraft technology is being considered to meet these targets.The importance of these technologies lies in their advancements in terms of aircraft life cycles and environmental benignity.Owing to these advancements,hybrid electric systems with more than one power source have become promising for the aviation industry,considering that the growth of air traffic is projected to double in the next decade.Hybrid technologies have given future hybrid fans and motor-fan engines potential as alternative power generators.Herein,Turboelectric Distributed Propulsion(TeDP)is discussed in terms of power distribution and power sources.The fundamentals of turbofan and turboshaft engines are presented along with their electricitygeneration mechanism.TeDP is discussed from a design viewpoint,with a detailed discussion of different types of hybrid electric and turboelectric systems.Examples of proposed TeDP aircraft models and numerical modelling tools used to simulate the performance of TeDP models are reviewed.Finally,innovative turboelectric systems in which electric power savers and mechanical gear changers have been discarded for weight optimisation are presented along with other prospective models,engines,approaches,and architectures.The findings of this review indicate the knowledge gaps in the field of numerical modelling for NASA’s TeDP and its capability to increase the efficiency by up to 24%with a 50%reduction in emissions relative to those of conventional gas turbines.