On the Innovative Design of Hybrid CVTs with Mechanical Reverse Driving Mode

Abstract

In response to growing global environmental awareness and stringent international laws and regulations on vehicle emissions the automotive industry is devoted to developing green vehicles Since modern electric vehicles exist lots of restrictions on battery technology and convenience that general consumers do not accept hybrid electric vehicles (HEVs) have been developed rapidly because it inherits the advantages from both conventional and electric vehicles HEVs can provide stable power and has well acceleration performance and even reduces fuel consumption and air pollution effectively Hybrid transmission plays an important role in coupling the power This research focuses on developing a systematic design procedure based on an extension of the Creative Mechanism Design Methodology to synthesize all feasible hybrid transmissions mainly on series-parallel systems with a mechanical reverse driving mode Analyses and computer simulation are also carried out to verify its feasibility Firstly vehicle and battery models are established and power sources are selected based on the performance requirements Then following the proposed design procedure and subject to the design constraints 21 novel hybrid CVTs are synthesized Among them 13 designs apply planetary gear trains (PGTs) and 8 designs use a chain drive to reach mechanical reverse driving mode Through a thorough evaluation one of them is selected for further design and analyses Stalling this system in a vehicle with known specifications it has the maximum vehicle speed of 226 km/h a 0 ~100 km/h acceleration time of 7 1439 seconds and gradeability of 51 16 % Finally a program is developed for computer simulation to analyze novel design’s fuel economy In addition a control strategy is built to shift to the suitable operation modes automatically according to the road conditions In order to achieve the optimum fuel economy specifications of the power sources and CVT smooth shifting and battery SOC are taken into account to conduct optimization for charging efficiency and fuel consumption Under EPA standard tests the proposed novel hybrid CVT consume 45 and 36 mpg in urban and highway respectively which is very competitive as compared to the other HEVs

Date of Award	2018 Jul 1
Original language	English
Supervisor	Hong-Sen Yan (Supervisor)