An Overview of Current Automatic, Manual and Continuously Variable Transmission Efficiencies and Their Projected Future Improvements

Kluger, Michael A.; Long, Denis M.

doi:10.4271/1999-01-1259

Cited by 84 publications

(70 citation statements)

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“…Losses in this highly efficient transmission [1] are ignored. The engine speed is assumed directly proportional to wheel speed based on the current transmission gear ratio R g ,…”

Section: B Modeling Assumptionsmentioning

confidence: 99%

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Incorporating drivability metrics into optimal energy management strategies for Hybrid Vehicles

Opila

Aswani

McGee

et al. 2008

2008 47th IEEE Conference on Decision and Control

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Abstract-Hybrid Vehicle fuel economy performance is highly sensitive to the energy management strategy used to select among multiple energy sources. Optimal solutions are easy to specify if the drive cycle is known a priori. It is very challenging to compute controllers that yield good fuel economy for a class of drive cycles representative of typical driver behavior. Additional challenges come in the form of constraints on powertrain activity, like shifting and starting the engine, which are commonly called "drivability" metrics. These constraints can adversely affect fuel economy. The benefits of including drivability restrictions in a Shortest Path Dynamic Programming (SPDP) formulation of the energy management problem are investigated for the first time. It is shown that this method yields up to 10% fuel economy improvement on a representative parallel electric hybrid when compared to a simpler instantaneous optimization formulation. This result is obtained by comparing a SPDP controller designed for drivability to a second SPDP controller, designed for fuel economy only, that uses an additional instantaneous optimization step for the incorporation of drivability. The results also quantify the tradeoff between drivability and fuel economy.

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“…Losses in this highly efficient transmission [1] are ignored. The engine speed is assumed directly proportional to wheel speed based on the current transmission gear ratio R g ,…”

Section: B Modeling Assumptionsmentioning

confidence: 99%

“…The behavior of the electrical system is a function of the battery SOC, as shown in (1). Thus the system efficiency is a function of three variables.…”

Section: Component Modelsmentioning

confidence: 99%

Incorporating drivability metrics into optimal energy management strategies for Hybrid Vehicles

Opila

Aswani

McGee

et al. 2008

2008 47th IEEE Conference on Decision and Control

View full text Add to dashboard Cite

show abstract

“…As compared to fixed ratio gearing, the efficiencies of variators are usually lower. Kluger and Long [9] suggested that the highest achievable overall efficiencies for the belt type and toroidal type CVT are expected to be 88.4% and 91% respectively. The PSCVT, a combination of variator and planetary gear set (PGS) (shown in fig.1), is usually used to improve the efficiency of the transmission by allowing part of the power to be transmitted via the highly efficient direct mechanical linkage while the rest of the power is transmitted through the variator.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Dual Mode Continuously Variable Transmission for Flywheel Energy Storage Systems

Dhand

Pullen

2016

SAE Technical Paper Series

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There are different types of energy storage devices which are used in today's hybrid and electric vehicles. Batteries, ultra capacitors and high speed flywheels are the most commonly used ones. While batteries and supercapacitors store energy in the form of electric energy, the flywheel (FW) is the only device that keeps the energy stored in the original form of mechanical energy the same as the moving vehicle. The flywheel needs to be coupled to the driveshaft of the vehicle in a manner which allows it to vary its speed independently of the moving vehicle in order to vary its energy content. In other words a continuously variable transmission (CVT) is needed. The common mechanical variators used in automotive applications, namely the rolling traction drives and the belt drives, have the disadvantage that their speed ratio range defined as the maximum to minimum speed ratio is generally not sufficient for flywheel energy storage system (FESS). One of the ways to improve the ratio range is by using a dual mode transmission, where the ratio coverage of the variator is exploited twice. This paper presents the fundamental kinematics of such a transmission including its variants. The equations of speed ratio, power flow and efficiency are derived for a variator only transmission and a power split CVT (PSCVT) used in dual mode and the results compared.

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“…The two rotors are the two mechanical ports of the transmission. The machine is able to transmit power from the input to the output shaft in an electromagnetic way only, so without meshing gears or wetplate clutches as is the case in conventional transmissions [2]. Moreover, the gear ratio between the input shaft and the output shaft can be varied continuously.…”

Section: Introductionmentioning

confidence: 99%

Torque Analysis on a Double Rotor Electrical Variable Transmission With Hybrid Excitation

Druant

Vansompel

Belie

et al. 2017

IEEE Trans. Ind. Electron.

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Abstract-An electrical variable transmission (EVT) can be used as a power splitting device in hybrid electrical vehicles. The EVT analyzed in this paper is a rotating field electrical machine having two concentric rotors. On the outer rotor, permanent magnets (PMs) are combined with a dcfield winding, being the first implementation of its kind. The magnetic field in the machine as well as the electromagnetic torque on both rotors are a function of the q-and d-axis currents of the stator and inner rotor, as well as the dc-field current. To describe and fully understand this multiple-input multiple-output machine, this paper gives an overview of the influence of the different current inputs on the flux linkage and torque on both rotors. Focus is given to the hybrid excitation in the d-axis by combining the dc-field current and the alternating currents. This has the advantage compared to other EVT topologies that unwanted stator torque can be avoided without stator d-axis current flux weakening. Results of the analysis are presented by means of the torque to current characteristics of a double rotor PM-assisted EVT, as well as the torque to current ratios. The machine characteristics are finally experimentally verified on a prototype machine.Index Terms-Electrical variable transmission (EVT), hybrid excitation, torque analysis.

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An Overview of Current Automatic, Manual and Continuously Variable Transmission Efficiencies and Their Projected Future Improvements

Cited by 84 publications

References 0 publications

Incorporating drivability metrics into optimal energy management strategies for Hybrid Vehicles

Incorporating drivability metrics into optimal energy management strategies for Hybrid Vehicles

Analysis of Dual Mode Continuously Variable Transmission for Flywheel Energy Storage Systems

Torque Analysis on a Double Rotor Electrical Variable Transmission With Hybrid Excitation

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