A dual input and 3-speed transmission for electric vehicles

Fang, Yuhong

A dual input and 3-speed transmission for electric vehicles

Fang, Yuhong

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Publication Type:: Thesis
Issue Date:: 2017

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Field	Value	Language
dc.contributor.author	Fang, Yuhong
dc.date.accessioned	2017-11-16T23:50:20Z
dc.date.available	2017-11-16T23:50:20Z
dc.date.issued	2017
dc.identifier.uri	http://hdl.handle.net/10453/120256
dc.description	University of Technology Sydney. Faculty of Engineering and Information Technology.	en_AU
dc.description.abstract	The transmission system is one of the most important mechanisms in the electric vehicle that determines the behaviour, power and electrical economy of a vehicle. Transmission performance is usually related to motor efficiency, gear shift noise and passenger comfort during the gear shifting. For the investigation of a transmission in an electric vehicle, this thesis provides a new and easy way, a diagram-model on the vehicle speed –vehicle torque (VS-VT) plane, as a basis to test the efficiency of an electric motor (EM) in a multi-speed powertrain. In the introduction of the new method, the existing 2-speed transmission powertrain test rig in the laboratory is used as the investigation object. To evaluate the new method, Simulink model and a testing rig in the laboratory are introduced with the same electric motor and gear ratios for transmission. Results demonstrate that the new method is simpler than the Simulink model and testing rig and can make the characteristics of the electric motor more visible rather than other methods, which provides a new direction for the selection and optimization of the transmission gear ratios and more opportunities for further investigation. For the investigation of the advantage of the 3-speed transmission in an electric vehicle, the optimized single, 2-speed, 3-speed and 4-speed transmission are introduced to have comparisons. For the optimisation of gear ratios, a new method based on the new diagram model, the Cycle Track Density (CTD), is introduced in the investigation, which makes the optimisation process of each gear ratio visible and pertinent. The matched power source model is from the UQM 125 traction system in the powertrain test rig of the University of Technology, Sydney. The comparison is done in terms of the performance of the vehicle, particularly the efficiency of the motor and evaluates the application of a 3-speed transmission in an electric vehicle. In the realization of a dual input 3-speed transmission, according to the construction of a 3-speed dual clutch transmission, an innovation of the shifting mechanism is introduced to replace the conventional synchronizer which is driven by a complex hydraulic system. The new mechanism is named as Harpoon-shift and has got a patent certificate. Based on the concept, there are three types of structures, all of which have patent certificates. This thesis selects the unilateral Harpoon-shift as the object of study and introduces the working process of this shift mechanism. For the testing of the new concept, a prototype of the Harpoon-shift is manufactured and a test rig is assembled. The testing is done with different springs and speed difference to test the properties of the Harpoon-shift. The results demonstrate the practicability and the advantages of the new mechanism over the conventional synchronizer.	en_AU
dc.format	Thesis (PhD)
dc.language.iso	en_AU	en_AU
dc.relation	https://opus.lib.uts.edu.au/bitstream/10453/120256/2/02whole.pdf
dc.rights	The author owns the copyright in this thesis including all reproduction and reuse rights for the work. The work may not be altered without the permission of the copyright owner. Attribution is essential when quoting or paraphrasing from this thesis.
dc.rights	info:eu-repo/semantics/openAccess
dc.rights	au.edu.uts.lib/ppc
dc.title	A dual input and 3-speed transmission for electric vehicles	en_AU
dc.type	Thesis	en_AU
utslib.copyright.status	open_access

Abstract:

The transmission system is one of the most important mechanisms in the electric vehicle that determines the behaviour, power and electrical economy of a vehicle. Transmission performance is usually related to motor efficiency, gear shift noise and passenger comfort during the gear shifting. For the investigation of a transmission in an electric vehicle, this thesis provides a new and easy way, a diagram-model on the vehicle speed –vehicle torque (VS-VT) plane, as a basis to test the efficiency of an electric motor (EM) in a multi-speed powertrain. In the introduction of the new method, the existing 2-speed transmission powertrain test rig in the laboratory is used as the investigation object. To evaluate the new method, Simulink model and a testing rig in the laboratory are introduced with the same electric motor and gear ratios for transmission. Results demonstrate that the new method is simpler than the Simulink model and testing rig and can make the characteristics of the electric motor more visible rather than other methods, which provides a new direction for the selection and optimization of the transmission gear ratios and more opportunities for further investigation. For the investigation of the advantage of the 3-speed transmission in an electric vehicle, the optimized single, 2-speed, 3-speed and 4-speed transmission are introduced to have comparisons. For the optimisation of gear ratios, a new method based on the new diagram model, the Cycle Track Density (CTD), is introduced in the investigation, which makes the optimisation process of each gear ratio visible and pertinent. The matched power source model is from the UQM 125 traction system in the powertrain test rig of the University of Technology, Sydney. The comparison is done in terms of the performance of the vehicle, particularly the efficiency of the motor and evaluates the application of a 3-speed transmission in an electric vehicle. In the realization of a dual input 3-speed transmission, according to the construction of a 3-speed dual clutch transmission, an innovation of the shifting mechanism is introduced to replace the conventional synchronizer which is driven by a complex hydraulic system. The new mechanism is named as Harpoon-shift and has got a patent certificate. Based on the concept, there are three types of structures, all of which have patent certificates. This thesis selects the unilateral Harpoon-shift as the object of study and introduces the working process of this shift mechanism. For the testing of the new concept, a prototype of the Harpoon-shift is manufactured and a test rig is assembled. The testing is done with different springs and speed difference to test the properties of the Harpoon-shift. The results demonstrate the practicability and the advantages of the new mechanism over the conventional synchronizer.

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