INTRODUCTION The Hybrid vehicle became popular after releasing the 3rd generation Prius, especially in the Japanese market; consequently CO2 environment was greatly improved. But Hybrid vehicles need to be released more to save our planet and to meet the world’s severe emission regulations which will be established in United States, Japan, Europe, BRICS and Middle East countries. On the other hand, driving comfort and “Hybrid drive ability” performance are also essential functions to increase the market share for hybrid vehicles. This paper describes the new generation hybrid system, which achieved extremely high efficiency, is compact and light, and has “Hybrid drive ability” performance. 1. OBJECTIVE OF THE DEVELOPMENT 1-1. Fuel Economy The previous hybrid system which is installed in 3rd Gen Prius, had a target to improve the high speed and cold ambient condition’s fuel economy. This system target is to maximize the potential of THS-II by re-design of all hybrid units to be able to improve the fuel economy. Specifically, mechanical and electrical losses were dramatically reduced for the transaxle, motor, and PCU. (Power Control Unit.) Also, the hybrid system including battery and software were designed to be able to maximize each unit’s performance. Li-ion and NiMH batteries are adopted for this system. The Li-ion battery has improved charge & discharge performance over the one which is adopted for Prius V (Japan market only). NiMH battery also has improved charging performance and durability. 1-2. Compact and Versatile This system is the base design for all future TOYOTA front wheel drive hybrid vehicles. Therefore, compactness and versatility is a crucial theme for this system. Trunk space utility improvements have been achieved due to minimization of the hybrid system.1-3. Hybrid System Structure Figure 1 shows the system structure. Figure.1. Hybrid System 2ZR-FXE Engine has improved fuel economy by achieving 40% brake thermal efficiency.The New Generation Front Wheel Drive Hybrid System Shunsuke Fushiki Toyota Motor Corporation ABSTRACT Introducing all-new front wheel drive hybrid system installed in the 2016 Toyota Prius. This system was completely re-designed to maximize the potential of THS-II (Toyota Hybrid System-II). This system was designed to be able to minimize the mechanical and electrical losses from the previous generation system, improve environmental performance, and also tried to reduce size and weight. We’d like to take this opportunity to introduce the new technology of each component, and hybrid system performance. CITATION: Fushiki, S., "The New Generation Front Wheel Drive Hybrid System," SAE Int. J. Alt. Power. 5(1):2016, doi:10.4271/2016- 01-1167.2016-01-1167 Published 04/05/2016 Copyright © 2016 SAE International doi:10.4271/2016-01-1167 saealtpow.saejournals.org Basic structure of this hybrid is the same as the previous one, but all units have been improved by minimizing size and achieving less friction for fuel economy. NiMH and Li-ion batteries are both adopted in the newly designed cell and a re-designed optimum layout is used to improve the size, weight and performance. 2. FEATURES OF MAIN COMPONENTS 2-1. Transaxle Figure.2 shows the section of new transaxle. Figure.2. Transaxle Structure A gear train structure has been adopted for the hybrid system. Including, 1. Parallel shaft gear type motor speed reduction device 2. Counter -driven gear using a double contacting structure 3. Compact motor The transaxle length has been shortened, and mechanical friction has been reduced based on these new structures. The Planetary system was adopted for the motor reduction device in the previous hybrid system. The new hybrid system utilizes a parallel shaft gear type instead of the former planetary system. By using this structure, this system was able to use a wider reduction ratio without increasing mechanical friction. The wider reduction ratio helps make the motor size smal