•Single reduction, DCT and CVT based battery electric vehicle models are compared.•Shifting schedules for two-speed DCT and simplified CVT are optimized.•Up to 14% motor efficiency improvements and ...15% energy saving are achieved.•Improvement results in multi-speed BEVs are experimentally validated.•Initial manufacturing cost, lifetime daily use and maintenance cost are presented.
Despite the long-term benefit of battery electric vehicles (BEVs) to customers and environment, the initial cost and limited driving range present significant barriers for wide spread commercialization. The integration of multi-speed transmissions to BEVs’ powertrain systems in place of fixed ratio reduction transmissions is considered as a feasible method to improve powertrain efficiency and extend limited driving range for a fixed battery size. The aim of this paper is to enable the researchers or BEV manufacturers, especially for transmission systems, to estimate whether their products are worthwhile for the customer in terms of the price/performance relationship of others’ design solutions. To do so a generic battery electric vehicle is modelled in Matlab/Simulink® to predict motor efficiency and energy consumption for single reduction, two speeds Dual Clutch Transmission (DCT) and simplified Continuous Variable Transmission (CVT) equipped battery electric vehicles. A credible conclusion is gained, through experimental validation of single speed and two speeds DCT scenarios and reasonable assumptions to support the CVT scenario, that both two speeds DCT and simplified CVT improve the overall powertrain efficiency, save battery energy and reduce customer costs. However, each of the configurations has unique cost and energy consumption related trade-offs.
This paper presents a Takagi-Sugeno (T-S) model-based fuzzy control design approach for electrohydraulic active vehicle suspensions considering nonlinear dynamics of the actuator, sprung mass ...variation, and constraints on the control input. The T-S fuzzy model is first applied to represent the nonlinear uncertain electrohydraulic suspension. Then, a fuzzy state feedback controller is designed for the obtained T-S fuzzy model with optimized H infin performance for ride comfort by using the parallel-distributed compensation (PDC) scheme. The sufficient conditions for the existence of such a controller are derived in terms of linear matrix inequalities (LMIs). Numerical simulations on a full-car suspension model are performed to validate the effectiveness of the proposed approach. The obtained results show that the designed controller can achieve good suspension performance despite the existence of nonlinear actuator dynamics, sprung mass variation, and control input constraints.
Nitrate is a reasonable alternative instead of nitrogen for ammonia production due to the low bond energy, large water‐solubility, and high chemical polarity for good absorption. Nitrate ...electroreduction reaction (NO3RR) is an effective and green strategy for both nitrate treatment and ammonia production. As an electrochemical reaction, the NO3RR requires an efficient electrocatalyst for achieving high activity and selectivity. Inspired by the enhancement effect of heterostructure on electrocatalysis, Au nanowires decorated ultrathin Co3O4 nanosheets (Co3O4‐NS/Au‐NWs) nanohybrids are proposed for improving the efficiency of nitrate‐to‐ammonia electroreduction. Theoretical calculation reveals that Au heteroatoms can effectively adjust the electron structure of Co active centers and reduce the energy barrier of the determining step (*NO → *NOH) during NO3RR. As the result, the Co3O4‐NS/Au‐NWs nanohybrids achieve an outstanding catalytic performance with high yield rate (2.661 mg h−1 mgcat−1) toward nitrate‐to‐ammonia. Importantly, the Co3O4‐NS/Au‐NWs nanohybrids show an obviously plasmon‐promoted activity for NO3RR due to the localized surface plasmon resonance (LSPR) property of Au‐NWs, which can achieve an enhanced NH3 yield rate of 4.045 mg h−1 mgcat−1. This study reveals the structure–activity relationship of heterostructure and LSPR‐promotion effect toward NO3RR, which provide an efficient nitrate‐to‐ammonia reduction with high efficiency.
Inspired by the enhancement effect of heterostructure, Au nanowires decorated ultrathin Co3O4 nanosheets (Co3O4‐NS/Au‐NWs) nanohybrids are proposed as electrocatalyst for nitrate electroreduction reaction. The Au nanowires not only promote the efficiency of nitrate reduction, but bring LSPR‐promotion effect for the Co3O4‐NS/Au‐NWs nanohybrids.
•A new topological shape optimization method for design of mechanical metamaterials.•Numerical homogenization method to evaluate the effective properties of the microstructure.•PLSM for topological ...shape evolutions of the microstructure to achieve desired properties.
Metamaterials usually refer to artificial composite materials consisting of an array of periodically arranged microstructures, engineered to provide unusual material properties that may not be easily found in nature. This paper proposes a new topological shape optimization method for systematic computational design of a type of mechanical metamaterials with negative Poisson’s ratios (auxetic materials), which integrates the numerical homogenization approach into a powerful parametric level set method (PLSM). The homogenization method is used to obtain the effective properties of the periodic microstructure, while the PLSM is applied to achieve shape evolutions and topological changes of the microstructure, until the desired material properties are achieved. The key concept of the PLSM is the interpolation of the implicit level set surface by using a given set of compactly supported radial basis functions (CSRBF), which are positioned at a number of given and fixed knots inside the design domain. Several typical numerical examples are used to demonstrate the favorable characteristics of the proposed method in the design of micro-structured metamaterials.
•An electric vehicle powertrain equipped with two motors and four-gear ratios.•A two-loop optimization framework combined by the global search method and NSGA-II.•Effect of sizing motors and gear ...ratios on energy efficiency.•Optimal shift schedules based on the equivalent efficiency of two motors, engaged gears, and driving conditions.•Comparably maximum efficiency achieved while avoiding repeated and unreasonable gear changes.
This paper aims to fully exploit the superior advantages in improving energy economy and dynamic performance of an electric vehicle powertrain equipped with two motors and multi-gear ratios. Considering the dependence of gear ratio selection on motor sizing, a two-loop optimization algorithm, combined by the global search method and non-dominated sorting genetic algorithm-II, is proposed to find optimal motor sizes and transmission ratios. An energy management strategy with novel shift schedules based on the equivalent efficiency of two motors, current engaged gears, and driving conditions is then recommended. The energy management strategy also optimizes the torque allocation to two motors to minimize electricity consumption. Subject to the total of motor peak powers being constant, simulation results for a case study of urban bus show that the optimization of both motor sizes and gear ratios considerably enhances the energy efficiency of powertrain system. In comparison with a single-motor powertrain, optimal motor scales of larger than 0.42 and corresponding gear ratios reduce the electricity consumption significantly by 4.82−5.08%. Besides, the introduced energy management strategy with optimal shift schedules is proved to ensure comparably maximum efficiency while effectively preventing unnecessary and repeated gear changes.
Modelling, experimental study, and field observation are prevailing research methods in coal mine support application. Many criteria and rationales have been established to evaluate the stability of ...coal mine excavations from both qualitative and quantitative perspectives. Nevertheless, most coal mine support designs are still highly dependent on empiricism or semi-empiricism, even with the existence of the aforementioned theories. Oftentimes, most lessons are learned via the trial and error approach. A more critical fact is that further in-depth improvement of or research into coal mine support appears to be largely bottlenecked. Under such circumstances, support failures in four representative coal mines in China are selected as research objects, through which dominating implied principles are investigated and re-clarified by field observations. In the Datong coal mine, an extremely fractured roadway is successfully maintained by simply changing the end-encapsulated bolting system to a fully bonded bolting system, with the results indicating the formation of an artificial compressive stress arch. In the Kongzhuang coal mine, a deep-buried shaft with a super-large section is effectively stabilized by tieback cable bolts, and a 561-day-long load-monitoring procedure verifies the effectiveness. In the Donghuantuo coal mine, the support ideology of retaining, reinforcing, and holding functions is presented to interpret bolt support failure under an aqueous environment. In the Hulusu coal mine, 5400-mm-span entries are stabilized by simply installing four tendons on the roof; the effectiveness is further proven, and an enhanced beam building mechanism is interpreted. At the end of this study, the effectiveness of a pretension force, a fully bonded bolting system, longer tendon support, and mesh/shotcrete is discussed. All of the examples given in this study are proposed to meet the principles of high efficiency, low cost, and operational friendliness. Additionally, the authors hope that through this paper, more comprehensive research/analytical methodologies will be able to bridge support theories and applications, which is the main purpose of this work.
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•Field observations of support failures were carried out in some representative coal mines in China.•Implicit mechanisms behind specific failure patterns were revealed by refining existing theories.•Mainstream support ideologies were discussed, and experience was reiterated and emphasized.
•Before rockburst, the sudden rise of MS energy and the lower level of event count.•When rockburst, peak value of fault total area, the lower b value, and |Z|>2.•When rockburst, the largest energy ...ratio in the dominant low-frequency band.•Before rockburst, abnormal cluster of sources and high-energy events congregation.•Prior to rockburst, the sudden drop of EME amplitude indicating macro-fracture.
•A parallel hydraulic hybrid vehicle model is built to research its powertrain dynamics.•Power on gear shift control strategy is designed to avoid torque interruption.•LQR is used to compromise ...vehicle vibration, driving comfort and dynamic performance.•Extended Kalman filter (EKF) is adopted to estimate the powertrain parameters.•Torque compensation capability is studied with different accumulator charging state.
The power on gear shift control of a parallel hydraulic hybrid vehicle (PHHV) is researched in this paper. A multibody dynamic model is built to capture the main vibration characteristics of PHHV powertrain, based on which the power on gear shift control strategy is designed and verified. To avoid the vehicle driving torque interruption during gear shift, power on gear shift control strategy is designed. In the control strategy, hydraulic pump/motor (HPM) compensates the engine torque when the engine clutch is disengaged for gear shift. The engine clutch engagement process is carefully controlled by LQR control strategy to mitigate the vehicle powertrain vibration and improve the vehicle driving comfort. Extended Kalman filter (EKF) is adopted to estimate the PHHV parameters required by LQR control. The available HPM torque depends on its working pressure which varies a lot with different accumulator state of charge. So the HPM torque compensation capability is investigated by analysing the traction force requirement during gear shift. To obtain the gear shift traction force demand, a gear shift schedule considering both vehicle fuel economy and dynamic performance is designed. The simulation results show that the HPM could satisfy most of the torque compensation requirements during gear shifts with the designed gear shift schedule in typical driving cycles.
Pyroptosis is triggered by inflammasomes after its activation by various inflammatory stimulations, including lipopolysaccharide (LPS) and improper pH. This may result in programmed death of the ...affected cell. It is well known that NLRP1 and NLRP3 inflammasomes mediate the production of various cytokines in inflammatory disorders; however, it is still unknown whether NLRP1 and NLRP3 inflammasomes can influence the LPS‑induced pyroptosis in the progression of knee osteoarthritis (KOA). In the present study, the correlation between the NLRP inflammasomes and fibroblast‑like synoviocytes (FLSs) pyroptosis was investigated in vivo and in vitro. Human synovial samples were collected from KOA patients and the expression of NLRP1 and NLRP3 inflammasomes was analyzed. Human FLS were isolated in vitro and stimulated with LPS. To determine whether NLRP1 and NLRP3 inflammasomes are involved in FLS pyroptosis, NLRP1 and NLRP3 small interfering RNAs (siRNAs) were used. The results showed that the expression of NLRPs and inflammasome‑related proteins were upregulated and FLS stimulated with LPS+ATP resulted in cell pyroptosis. However, LPS+ATP‑induced pyroptosis was attenuated by NLRP1 and NLRP3 siRNAs. The results of the present study indicate that LPS‑induced FLS pyroptosis may be mediated by either NLRP1 or NLRP3 inflammsomes. Overall, based on the data obtained from patients and in vitro cells, the present finsings showed that NLRP1 and NLRP3 inflammasomes are highly involved in the FLS inflammation and pyroptosis. Furthermore, inhibition of NLRP1 and NLRP3 led to a remarkable reduction of pyroptosis‑related cytokines. Thus, NLRP1 and NLRP3 inflammasomes may be important in the pathogenesis of OA and may represent a novel therapeutic target.
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