Efficient Exhaustive Search of Power-Split Hybrid Powertrains With Multiple Planetary Gears and Clutches

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Xiaowu Zhang ◽  
Shengbo Eben Li ◽  
Huei Peng ◽  
Jing Sun
Keyword(s):  
Planetary Gear ◽  
Optimal Designs ◽  
Computationally Efficient ◽  
Energy Management Strategy ◽  
Screening Process ◽  
Automated Modeling ◽  
Operating Modes ◽  
Hybrid Powertrains ◽  
Power Split ◽  
And Control

Planetary gear (PG) power-split hybrid powertrains have been used in producing hybrid and plug-in hybrid vehicles from the Toyota, General Motor, and Ford for years. Some of the most recent designs use clutches to enable multiple operating modes to improve launching performance and/or fuel economy. Adding clutches and multiple operating modes, however, also increases production cost and design complexity. To enable an exhaustive but fast search for optimal designs among a large number of hardware configurations, clutch locations, and mode selections, an automated modeling and screening process is developed in this paper. Combining this process with the power-weighted efficiency analysis for rapid sizing method (PEARS), an optimal and computationally efficient energy management strategy, the extremely large design space of configuration, component sizing, and control becomes feasible to search through. This methodology to identify optimal designs has yet to be reported in the literature. A case study to evaluate the proposed methodology uses the configuration adopted in the Toyota Hybrid Synergy (THS-II) system used in the Prius model year 2010 and the Hybrid Camry. Two designs are investigated to compare with the simulated Prius design: one uses all possible operating modes; and the other uses a suboptimal design that limits the number of clutches to three.

Automated Modeling and Mode Screening for Exhaustive Search of Double-Planetary-Gear Power Split Hybrid Powertrains

2014 ◽  
Author(s):  
Xiaowu Zhang ◽  
Huei Peng ◽  
Jing Sun ◽  
Shengbo Li
Keyword(s):  
Planetary Gear ◽  
General Motors ◽  
Screening Process ◽  
Automated Modeling ◽  
Operating Modes ◽  
Hybrid Powertrains ◽  
Power Split ◽  
Model Year ◽  
Operation Flexibility

Double Planetary Gear (PG) power-split hybrid powertrains have been used in production vehicles from Toyota and General Motors. Some of the designs use clutches to achieve multiple operating modes to improve powertrain operation flexibility and efficiency at the expense of higher complexity. In this paper, an automatic modeling and screening process is developed, which enables exhaustively search through all designs with different configurations, clutch locations and operating modes. A case study was conducted based on the configuration used in the model year 2010 Prius and Camry hybrids. It was found that by adding clutches, fuel economy can be improved significantly for plug-in hybrid (charge depletion) operations.

Rapid Optimization of Multiple-Planetary-Gear Power-Split Hybrid Powertrains

2015 ◽  
Author(s):  
Weichao Zhuang ◽  
Xiaowu Zhang ◽  
Huei Peng ◽  
Liangmo Wang
Keyword(s):  
Design Space ◽  
Planetary Gear ◽  
Optimization Method ◽  
Exhaustive Search ◽  
Combination Method ◽  
Hybrid Powertrain ◽  
Operating Modes ◽  
Hybrid Powertrains ◽  
Power Split ◽  
Computationally Intensive

In recent years, clutches have been used to create multi-mode power-split hybrid electric vehicles (HEVs). Designing an HEV for optimal performance is computationally intensive because of the enormous design space. For single planetary gear (PG) or a double-PG hybrid powertrains, the design with the best fuel economy and launching performance can be identified through exhaustive search. Exhaustive search for a hybrid powertrain with 3PGs is computationally expensive, because of the astronomical number of design candidates. To address the design problem with extremely large design space, a rapid structure optimization method is proposed, which is based on combining different operating modes. A case study compares several different schemes against the results of the exhaustive search. The results show that the proposed mode combination method can identify almost 90% of the best designs. The proposed method shows great potential when applied to hybrid systems with three or more PGs.

scholarly journals Configuration optimization for improving fuel efficiency of power split hybrid powertrains with a single planetary gear

2018 ◽  
Vol 214 ◽  
pp. 103-116 ◽  
Author(s):  
Huanxin Pei ◽  
Xiaosong Hu ◽  
Yalian Yang ◽  
Xiaolin Tang ◽  
Cong Hou ◽  
...  
Keyword(s):  
Fuel Efficiency ◽  
Planetary Gear ◽  
Configuration Optimization ◽  
Hybrid Powertrains ◽  
Power Split

scholarly journals Optimal design of three-planetary-gear power-split hybrid powertrains

2016 ◽  
Vol 17 (2) ◽  
pp. 299-309 ◽  
Author(s):  
W. Zhuang ◽  
X. Zhang ◽  
D. Zhao ◽  
H. Peng ◽  
L. Wang
Keyword(s):  
Optimal Design ◽  
Planetary Gear ◽  
Hybrid Powertrains ◽  
Power Split

Application of dynamic band brake model for enhanced drivetrain simulation

2002 ◽  
Vol 216 (11) ◽  
pp. 873-881 ◽  
Author(s):  
Y Fujii ◽  
W E Tobler ◽  
E M Clausing ◽  
T W Megli ◽  
M Haghgooie
Keyword(s):  
Automatic Transmission ◽  
Planetary Gear ◽  
Operating Conditions ◽  
Computationally Efficient ◽  
Vehicle Performance ◽  
Shift Quality ◽  
Friction Component ◽  
Experimental Approaches ◽  
And Control ◽  
Analytical Tools

In a modern vehicle design process, analytical tools are widely employed to complement experimental approaches for design evaluation. When effectively utilized, they lead to a reduced development time with improved vehicle performance. The development process of an automatic transmission (AT) system can benefit from an analytical representation which accurately captures AT shifting behaviours. In a typical AT system, friction components such as wet clutches and band brakes are utilized to alter planetary gear configurations for automatic shifting. Thus, an accurate representation of friction component dynamics is critical in predicting AT shifting behaviour. Engagement characteristics of friction components vary widely under different operating conditions. Although the basic engagement physics was identified in the 1970s, it is relatively recently that a predictive, yet computationally efficient model became available. This paper describes the first attempt to utilize a dynamic friction component model in drivetrain simulations. Specifically, a dynamic band brake model is implemented to predict the up-shift behaviour of a four-speed AT system under various operating conditions. Simulation results are qualitatively validated with experimental data obtained from a dynamometer test stand. The dynamic band brake model enhances the shift predictability of a drivetrain model and potentially allows analytical evaluation of shift quality and control strategy.

Failure Analysis of Planetary Gear Shaft of Power Split Device Based on Multi-Body Dynamics

2013 ◽  
Vol 433-435 ◽  
pp. 17-20 ◽  
Author(s):  
Yan Liu ◽  
Jing Fang Ji ◽  
Long Kong ◽  
Yan Li ◽  
Ji Xin Wang
Keyword(s):  
Hybrid Electric Vehicle ◽  
Coupled Model ◽  
Planetary Gear ◽  
Threshold Function ◽  
Power Performance ◽  
Body Dynamics ◽  
Power Split ◽  
The Moment ◽  
Multi Body ◽  
And Control

Power split device (PSD) affects the power performance and control strategy of hybrid electric vehicle (HEV). In this paper, a new threshold function for wavelet denoising is used to reduce noise in test torque and rotational speed data. The dynamic simulation is carried out at the moment of planetary gear shaft (PGS) failure, after the rigid-flexible coupled model of PSD is established. According to the obtained stress of PGS, analysis of PGS fracture is verified.

Rapid optimal design of a multimode power split hybrid electric vehicle transmission

2018 ◽  
Vol 233 (3) ◽  
pp. 740-762 ◽  
Author(s):  
Pier Giuseppe Anselma ◽  
Yi Huo ◽  
Joel Roeleveld ◽  
Ali Emadi ◽  
Giovanni Belingardi
Keyword(s):  
Electric Vehicle ◽  
Fuel Economy ◽  
Hybrid Electric Vehicle ◽  
Design Methodology ◽  
Planetary Gear ◽  
Optimal Designs ◽  
Design Parameters ◽  
Power Split ◽  
Planetary Gear Sets ◽  
Hybrid Electric

This work aims at presenting a design methodology capable of modeling, generating, and testing a large number of multimode power split hybrid electric vehicle transmission designs in a relatively short period of time. Design parameters include the planetary gear ratios, the final drive ratio, the configuration of hookups to link the hybrid powertrain components to the planetary gear sets and the locations of clutch connections between different nodes of the planetary gear sets. The system modeling approach is first presented, including formulations for each component (the vehicle and road load, the engine, the motor/generators and the battery). A rapid and automated modeling procedure is proposed for hybrid electric vehicle transmissions including multiple planetary gear sets and clutch connections. Two algorithms are subsequently presented that enable fast evaluation of fuel economy and acceleration performance of hybrid electric vehicle transmission designs, namely the enhanced Power-Weighted Efficiency Analysis for Rapid Sizing and the Rapid Efficiency-based Launching Performance Analysis algorithms. The developed design methodology is tested by first modeling and evaluating three hybrid electric vehicle designs from the state-of-art. Later, an investigation for optimal designs that can ameliorate the examined benchmarks is performed. Several millions of design options are rapidly generated and tested using the proposed procedure. The methodology is proved effective by quickly coming up with two sub-optimal designs. Fuel economy and acceleration performance are improved by 5.56% and 40.56%, respectively, compared to the corresponding best benchmarks.

Autonomy and control in the wish to die in terminally ill patients: A systematic integrative review

2021 ◽  
pp. 1-8
Author(s):  
Andrea Rodríguez-Prat ◽  
Donna M. Wilson ◽  
Remei Agulles
Keyword(s):  
Cultural Context ◽  
Personal Autonomy ◽  
Empirical Studies ◽  
Academic Library ◽  
Integrative Review ◽  
Free Text ◽  
Screening Process ◽  
Mesh Terms ◽  
Wish To Die ◽  
And Control

Abstract Background/Objective Personal autonomy and control are major concepts for people with life-limiting conditions. Patients who express a wish to die (WTD) are often thought of wanting it because of loss of autonomy or control. The research conducted so far has not focused on personal beliefs and perspectives; and little is known about patients’ understanding of autonomy and control in this context. The aim of this review was to analyze what role autonomy and control may play in relation to the WTD expressed by people with life-limiting conditions. Methods A systematic integrative review was conducted. The search strategy used MeSH terms in combination with free-text searching of the EBSCO Discovery Service (which provides access to multiple academic library literature databases, including PubMed and CINAHL), as well as the large PsycINFO, Scopus, and Web of Science library literature databases from their inception until February 2019. The search was updated to January 2021. Results After the screening process, 85 full texts were included for the final analysis. Twenty-seven studies, recording the experiences of 1,824 participants, were identified. The studies were conducted in Australia (n = 5), Canada (n = 5), USA (n = 5), The Netherlands (n = 3), Spain (n = 2), Sweden (n = 2), Switzerland (n = 2), Finland (n = 1), Germany (n = 1), and the UK (n = 1). Three themes were identified: (1) the presence of autonomy for the WTD, (2) the different ways in which autonomy is conceptualized, and (3) the socio-cultural context of research participants. Significance of results Despite the importance given to the concept of autonomy in the WTD discourse, only a few empirical studies have focused on personal interests. Comprehending the context is crucial because personal understandings of autonomy are shaped by socio-cultural–ethical backgrounds and these impact personal WTD attitudes.

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