Results 1 - 10 of 292
Results 1 - 10 of 292. Search took: 0.024 seconds
|Sort by: date | relevance|
[en] There are many kinds of methods to estimate the energy requirement or fuel consumption in the optimal design and minimize the life cost of a building. The bin method is one of the most popular ways to estimate the energy performance of a building, which is based on the hourly-based outdoor dry-bulb temperatures of all days in a whole year. There is lack of information about the bin weather data in China. In this paper, the ambient temperature bin data for 26 cities in China are generated. Based on the method used in this paper, the bin data can be calculated with the long-term daily weather record or TMY weather data, the deviation between them is acceptable. The bin data given in this paper may have the positive impact on building energy conservation in China
[en] The second part of the paper 'Hybridization of powertrain and downsizing of IC engine' presents an extensive analysis and parametric study of hybrid powertrain parameters for different drive cycles and electric energy storage devices as well as the results of vehicle dynamics. The analysis is based on the simulation model and analytical groundwork presented in Part 1. Very good agreement of the simulation and analytical results gives confidence in the accuracy of the performed analysis. Thus, the combined simulation and analytical analysis enables deep insight into the energy flow and energy loss phenomena in hybrid powertrains and reveals the advantages and disadvantages of hybrid powertrains running under different operating conditions. The analysis covers a broad range of parallel hybrid powertrain configurations spreading from mild- to full-hybrids. The aim of this paper is to indicate the influencing parameters that lead to an optimal combination of hybrid powertrain components in order to achieve an improved fuel economy of hybrid powertrains with the emphasis on drive cycle load as well as component sizes and efficiencies. It is shown in the paper that parallel hybrid powertrains exhibit considerable potential for higher energy conversion efficiency compared with conventional powertrains if their constituting components are sized adequately
[en] Highlights: • A regenerative braking system is designed for a rear-driven electric minivan. • A new control strategy coordinating energy efficiency and braking feel is proposed. • The control strategy is verified by simulation and hardware-in-loop (HIL) tests. • The proposed control strategy offers higher regeneration efficiency. - Abstract: As of to 2012, minivan ownership stood at 20 million units in China, accounting for 16% of the passenger car market. In this article, comprehensive research is carried out on the design and control of a regenerative braking system for a rear-driven electrified minivan. For improving the regeneration efficiency by as much as possible, a new regenerative braking control strategy called “modified control strategy” is proposed. Additionally, a control strategy called “baseline control strategy” is introduced as a comparative control strategy. Simulations and hardware-in-loop (HIL) tests are carried out. The results of the simulations and the HIL tests show that the modified control strategy offers considerably higher regeneration efficiency than the baseline control strategy. In normal deceleration braking, the regeneration efficiency of the modified control strategy reaches 47%, 15% higher than that of the baseline control strategy. In addition, improvement in the fuel economy of electric vehicles operating on the ECE driving cycle and enhanced with the modified control strategy is greater than 10%, which is 3% higher than that with the baseline control strategy
[en] Highlights: • Innovative hybrid powertrain system using a planetary gearset and dual one-way clutch. • Three operation modes: EV-mode, engine-driven mode and power split e-CVT mode. • Outstanding energy improvement (max. 32+%) compared to traditional vehicles. • Experimentally implemented for light-duty vehicles in the near future. - Abstract: The power split electronic-continuously variable transmission (e-CVT) has been globally accepted as a main architecture for developing a hybrid electric vehicle (HEV). In this paper, a novel full hybrid electric motorcycle with power split e-CVT is proposed. It consists of an engine, a reversible generator, a reversible driving motor, a set of the planetary gear, two one-way clutches, and transmission components arranged for a planetary gearset and dual one-way clutch transmission (PDOC). Three operation modes were properly switched for optimal output dynamics: EV-mode, engine-driven mode, and power split e-CVT mode. Performance simulation compared with that of a baseline system using the conventional rubber-belt CVT is conducted to evaluate its feasibility and potential. The results present superior driving performance and fuel economy for the proposed motorcycle (maximum 32% fuel economy improvement) and thus offer a favorable support for further development
[en] Highlights: • A 7-degree-of-freedom model of hybrid electric vehicle with regenerative braking system is built. • A modified nonlinear model predictive control strategy is developed. • The particle swarm optimization algorithm is employed to solve the optimization problem. • The proposed control strategy is verified by simulation and hardware-in-loop tests. • Test results verify the effectiveness of the proposed control strategy. - Abstract: As one of the main working modes, the energy recovered with regenerative braking system provides an effective approach so as to greatly improve fuel economy of hybrid electric bus. However, it is still a challenging issue to ensure braking stability while maximizing braking energy recovery. To solve this problem, an efficient energy recovery control strategy is proposed based on the modified nonlinear model predictive control method. Firstly, combined with the characteristics of the compound braking process of single-shaft parallel hybrid electric bus, a 7 degrees of freedom model of the vehicle longitudinal dynamics is built. Secondly, considering nonlinear characteristic of the vehicle model and the efficiency of regenerative braking system, the particle swarm optimization algorithm within the modified nonlinear model predictive control is adopted to optimize the torque distribution between regenerative braking system and pneumatic braking system at the wheels. So as to reduce the computational time of modified nonlinear model predictive control, a nearest point method is employed during the braking process. Finally, the simulation and hardware-in-loop test are carried out on road conditions with different tire–road adhesion coefficients, and the proposed control strategy is verified by comparing it with the conventional control method employed in the baseline vehicle controller. The simulation and hardware-in-loop test results show that the proposed strategy can ensure vehicle safety during emergency braking situation and improve the recovery energy almost 17% compared with the conventional rule-based strategy in the general braking situation. Therefore, the proposed control strategy might offer a theoretical reference for the design of the actual braking controller in engineering practice.
[en] Highlights: • Design, simulation, and manufacturing of a hybrid electric motorcycle are explained. • The electric machine is mounted in the front wheel hub of an ordinary motorcycle. • Two different energy control strategy are implemented. • The simulation results show that the motorcycle performance is improved. • The acceleration is improved and the fuel consumption and pollutions are decreased. - Abstract: In this paper, design, simulation, and conversion of a normal motorcycle to a Hybrid Electric Motorcycle (HEM) is described. At first, a simple model designed and simulated using ADVISOR2002. Then, the controller schematic and its optimized control strategy are described. A 125 cc ICE motorcycle is selected and converted into a HEM. A brushless DC (BLDC) motor assembled in the front wheel and a normal internal combustion engine in the rear wheel propel the motorcycle. The nominal powers are 6.6 kW and 500 W for the ICE and BLDC respectively. The original motorcycle has a Continuous Variable Transmission (CVT) that is the best choice for a HEM power transmission because it can operate in the automatic handling mode and has high efficiency. Moreover, by using the CVT, the ICE can be started while motorcycle is running. Finally, three operating modes of HEM, two implemented energy control strategies, and HEM engine control system by servomotors, and LCD display are explained
[en] The aim of this two part paper is to present the results of extensive simulation and analytical analysis of the energy conversion efficiency in parallel hybrid powertrains. The simulation approach is based on an accurate and fast forward facing simulation model of a parallel hybrid powertrain and a conventional internal combustion engine powertrain. The model of the ICE is based on a verified dynamic model that provides sufficiently small time steps to model adequately the dynamics of electric systems during transient test cycles. Models of the electrical devices enable computation of the instantaneous energy consumption, production and storage as well as computation of the instantaneous energy losses and component efficiencies. Moreover, the paper offers an analytical approach based on the energy balance in order to analyze and predict the energy conversion efficiency of hybrid powertrains. The analysis covers a broad range of parallel hybrid powertrain configurations from mild to full hybrids. Combined simulation and analytical analysis enables deep insight into the energy conversion phenomena in hybrid powertrains. The paper reveals the conditions and influences that lead to improved fuel economy of hybrid powertrains with the emphasis on determining the optimum hybridization ratio. The theoretical background, simulation program and brief analysis of one test cycle are presented in Part 1, whereas the extensive analysis and parametric study is presented in the companion paper, Part 2
[en] Highlights: • Modeling the variability of the fuel costs over long term. • Modeling the Multi-Source System taking into account changes in fuel costs. • Limiting the number of starts of the diesel generator to increase its lifecycle. • Increasing the fuel cost can lead to an increase of 18% in the design cost. • Optimization algorithm favors the introduction of renewable sources. - Abstract: Multi-Source Systems combining renewable energy sources with diesel generators have been widely adopted in isolated sites. The economic and ecological aspects are very important for analyzing and evaluating such systems. In this paper, an optimization approach that includes the former aspects has been proposed. This approach takes into account the changes in the fuel cost over a lifecycle and the minimization of the greenhouse gas emission. The proposed method is based on three main steps. At first, a fuel cost progression model over a period of 40 years has been developed. Second, due to the complexity of such systems and in order to simplify the modeling, meta-models have been extracted by using the Design of Experiments technique. Finally, Single-Objective and Multi-Objective Optimization of the system based on economic and ecological criteria have been performed. The obtained results show that, changes in fuel costs have a significant influence on the sizing of the system. Indeed, the increase in fuel cost can lead to an increase of 18% in the design cost. The best solution on Pareto’s curve was found with a reduction rate in the fuel consumption between 30 and 35%. Furthermore, the optimization algorithm favors the introduction of renewable sources.
[en] Highlights: • A complex EMR model of a new railcar range has been developed. • A satisfactory assessment of the fuel consumption of the railcar. • The significant potential benefits are attainable by hybridizing the original railcar. • The regenerative braking can provide up to 240 kW h saving. - Abstract: Energetic Macroscopic Representation (EMR) modelling approach is proposed to perform model-based reverse-engineering of a new railcar range, having six propulsion units, each consisting of a diesel engine and a traction motor. Particularly, EMR intrinsic features were exploited to perform phenomenological structuration of power flows, thus allowing proper and comprehensive modelling of complex systems, such as the under-study railcar. Based on some prospective real trips, selected in such a way as to enable realistic evaluation of effective railcar effort, EMR-based prediction of railcar energy consumption is performed. Furthermore, physical consistency of each powertrain component operation was carefully verified. The suitability of EMR approach was thus proven effective to perform reverse-engineering of known specifications and available experimental data, with the final aim of reconstructing a high fidelity computational tool that meets computational burden requirements for subsequent model-based tasks deployment. Finally, specific simulation analyses were performed to evaluate the potential benefits attainable through electric hybridization of the original powertrain.
[en] Highlights: • Correlation among resources, emissions, key components and processes was attained. • Environmental benefits of innovative power systems were verified. • New-build system showed a great advantage over retrofit and conventional systems. • Relative contribution of significant components remained or became more profound. • Influence of fuel consumption quantity over the estimates varied with impact types. - Abstract: Despite growing interest in advanced marine power systems, knowledge gaps existed as it was uncertain which configuration would be more environmentally friendly. Using a conventional system as a reference, the comparative life cycle assessment (LCA) study aimed to compare and verify the environmental benefits of advanced marine power systems i.e. retrofit and new-build systems which incorporated emerging technologies. To estimate the environmental impact attributable to each system, a bottom-up integrated system approach was applied, i.e. LCA models were developed for individual components using GaBi, optimised operational profiles and input data standardised from various sources. The LCA models were assessed using CML2001, ILCD and Eco-Indicator99 methodologies. The estimates for the advanced systems were compared to those of the reference system. The inventory analysis results showed that both retrofit and new-build systems consumed less fuels (8.28% and 29.7% respectively) and released less emissions (5.2–16.6% and 29.7–55.5% respectively) during operation whilst more resources were consumed during manufacture, dismantling and the end of life. For 14 impact categories relevant to global warming, acidification, eutrophication, photochemical ozone creation and PM/respiratory inorganic health issues, reduction in LCIA results was achieved by retrofit (2.7–6.6%) and new-build systems (35.7–50.7%). The LCIA results of the retrofit system increased in ecotoxicity (1–8%), resource depletion (1–2%) and fossil fuel depletion (17.7–161.9%). Larger magnitude of increase was shown by the new-build system in ecotoxicity (90–93.9%) and fossil fuel depletion (391.3%) as a result of handling additional scrap. Relative contribution of significant components towards environmental impact remained profound for the retrofit system (i.e. more than 84% for all impact categories) and became more prominent for the new-build system (approximately 99% for 18 impacts). For retrofit and new-build systems respectively, changes in fuel consumption quantity by ±10% and ±20% varied (i) ecotoxicity and land use by no means, (ii) fossil fuel depletion by 0.95–1.50 and 4.81–5.01 times assessed by CML2001 (or 0.95–1.50 and 5.12–5.32 times assessed by Eco-Indicator99); and (iii) the remaining impact categories by 0.65–1.37 and 0.34–0.92 times. The new-build system showed the greatest mitigation potential in 18 impact categories. The retrofit system was more environmentally friendly than the reference system. Appropriate life cycle management was warrant to avoid burden shifting whilst alleviating the environmental burdens at the same time.