Power losses in power-split CVTs: A fast black-box approximate method

Rotella, Dario; Cammalleri, Marco

doi:10.1016/j.mechmachtheory.2018.06.011

Cited by 19 publications

(39 citation statements)

References 31 publications

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“…Also for these cases, the last column of Table 2 shows the additional conditions to distinguish them. In conclusion, known τ W1 and τ W2 or calculated through Equations ( 9) and (10) (or Equations (11) and (12), using Table 2 it is possible to uniquely identify the power flow that is established in the Compound. For example, if τ W1 > 1 τ eCVTm and τ W2 < 0 the power flow is type (f).…”

Section: Case Nmentioning

confidence: 99%

“…Consequently, it is interesting to evaluate the value of the eCVT power. It has been demonstrated in References [12][13][14], that the power through the eCVT branch, divided by the input power of the overall CVU, can be easily calculated, independently on the internal arrangement of the CVU, under the assumption of negligible power loss (ideal CVU), by:…”

Section: Efficiency In Compound Power-split Cvumentioning

confidence: 99%

“…The availability of two transmission modes overcome the problems of the single mode powertrain, providing better vehicle performance in terms of fuel economy, acceleration and motor size [9][10][11]. Beside the input power split eCVT, there are more complex solutions with several transmission modes considering, in the system layout, at least two epicyclical gear trains and one or more locking system [12][13][14]. These solutions can be classified as compound type power split and examples are given by the devices developed by Allison, Timken, Renault, Toyota and by the GM/Daimler/BMW joint project called Global Hybrid Cooperation [5].…”

Section: Introductionmentioning

confidence: 99%

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Power Flows in Compound Transmissions for Hybrid Vehicles

Pinto

Mantriota

2019

Machines

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Hybrid electric vehicle (HEV) traction systems are the most promising technologies being characterized by high performance, high fuel efficiency, low emissions and long operating range. Significant improvements can be achieved equipping transmissions with variable transmission ratio such as power-split transmission and a compound power-split electric continuously variable transmission (eCVT). These systems have been introduced to improve vehicle global efficiency since they can maximize the efficiency in different operating conditions. Optimal design and control of these systems leads improvements in vehicles performance and mathematical models, which support the preliminary design phase, can play a key role in this field. In this work, the internal power circulations of “four-port-mechanical-power split device are determined through a dynamic analysis.” Finally, the efficiency of the compound transmission is analytically evaluated, assuming that the overall losses are linked to the eCVT variator.

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Section: Case Nmentioning

confidence: 99%

Section: Efficiency In Compound Power-split Cvumentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Power Flows in Compound Transmissions for Hybrid Vehicles

Pinto

Mantriota

2019

Machines

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“…The approach adopted herein is based on the concept of virtual or potential power, at the base of thoughtful contributions on the mechanical efficiency of planetary gear trains [5,[16][17][18][19][20][21][22]. The virtual power, a term coined by Chen and Angeles [17], or potential power, coined by Esmail [5], is the power measured by an observer on any arbitrary moving frame [23,24].…”

Section: Introductionmentioning

confidence: 99%

Power-Flow and Mechanical Efficiency Computation in Two-Degrees-of-Freedom Planetary Gear Units: New Compact Formulas

2021

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The mechanical efficiency is a computed value for comparing the performance of the multi degrees-of-freedom geared transmissions of hybrid vehicles. Most of the current methods for estimating gear trains mechanical efficiency require the decomposition of gear transmissions in basic structural elements or planetary gear units (PGU). These are two degrees-of-freedom components whose mechanical efficiency has a deep influence on the overall device. The authors (E.L.E., E.P.) already evidenced that, under certain kinematic conditions, the classic Radzimovsky’s formulas, widely accepted for computing the mechanical efficiency of PGUs, are not adequate. In this paper, more general and reliable formulas for computing the mechanical efficiency are deduced. The proposed formulas herein, exploiting the concept of potential or virtual power, evidence the dependency between kinematics and efficiency. A numerical example compares our results with previous work on the subject.

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“…Planetary gearboxes are mostly used for automatic transmission in lightweight vehicles [1]; however, other application areas have also been indicated in the literature [2]. Besides the conventional vehicle, the planetary transmission is used in the modern hybrid vehicle as a power-split device [3]. There are several reasons for its popularity, such as the compactness of the gear train, the capability of producing higher reduction ratios, multiple gear ratios from single planetary gear set and higher torque carrying capacity [2].…”

Section: Introductionmentioning

confidence: 99%

Modeling for design simplification and power-flow efficiency improvement in an automotive planetary gearbox: A case example

Tamada¹,

Chandra²,

Patra³

et al. 2020

FME Transactions

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An approach for design simplification and improvement in power-flow efficiency of an automotive planetary gearbox is presented in this article. Integrated CAD-CAE model, formed on stick diagram representation of geartrain operation, is developed for gleaning efficient gearbox configuration. A stick diagram for a three-stage planetary gearbox is a case exemplified here. CAE/simulation for dynamic analysis is conducted to determine deformation in geartrain. Powertrain model of the vehicle, Saturn-SL1, is selected from NREL ADVISOR. The power flow efficiency for each gear ratio is computed using DelCastillo's principle, and deformation is analysed to identify suitable gear ratios. It is observed that designing gearbox with five ratios yields higher efficiency than with seven. The developed model is tested on MATLAB, with New Europian Driving Cycle, to specify best operating range.Higher efficiency range is underscored, that is, driving in second through fourth gear. The proposed approach specifies driving conditions and efficiency while designing a gearbox.

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Power losses in power-split CVTs: A fast black-box approximate method

Cited by 19 publications

References 31 publications

Power Flows in Compound Transmissions for Hybrid Vehicles

Power Flows in Compound Transmissions for Hybrid Vehicles

Power-Flow and Mechanical Efficiency Computation in Two-Degrees-of-Freedom Planetary Gear Units: New Compact Formulas

Modeling for design simplification and power-flow efficiency improvement in an automotive planetary gearbox: A case example

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