2020-01-0850 Published 14 Apr 20 20Development of New Hybrid Transaxle for Mid-Size Sports Utility Vehicles Seitaro Nobuyasu, Shigetsugu Iwata, Masabumi Nishigaya, Yoshiteru Hagino, Masatoshi Ito, and Hiroshi Aihara Toyota Motor Corporation Citation: Nobuyasu, S., Iwata, S., Nishigaya, M., Hagino, Y. et al., “Development of New Hybrid Transaxle for Mid-Size Sports Utility Vehicles,” SAE Technical Paper 2020-01-0850, 2020, doi:10.4271/2020-01-0850. Abstract Toyota has developed a new Hybrid (HV) transaxle P810 for Mid-Size SUVs to improve fuel efficiency and power performance. The transaxle was developed based on Toyota's new development strategy  - Toyota New Global Architecture (TNGA). By adopting technologies to shorten overall length of the transaxle, installation into the same engine compartment of Mid-Size sedans have been realized while also improving the motor output. This paper will intro - duce technologies regarding the new mount structure for shortening overall length, and furthermore, noise reduction related to this mount structure. 1.  Introduction Since the launch of the first generation Prius in 1997 as the world’s first mass-production HV [ 1, 2, 3], customer demands for enhancing environmental performance and electrification have continued to rise. Furthermore, as environmentally friendly vehicles have become more wide spread, customers have also demanded higher levels of dynamic performance and quietness. Next generation HV transaxles - P610 for Compact-Class vehicles [ 4] and P710 for Mid-Size sedans [ 5], based on TNGA design philosophy are in mass production to meet a wide variety of needs. As the next generation HV transaxle for Mid-Size SUVs, the P810 has been developed to achieve world class performance levels in various aspects. This paper introduces the main characteristics and performances of P810, especially overall length shortening structure on the motor axis leading to driving force enhance - ment in EV mode, as well as noise and vibration (NV) reduction technologies. 2.  Development Aims The development aims of P810 were as follows: 1 . R educe mechanical loss to enhance fuel economy. 2 . E nhance the driving force in EV mode. 3 . R educe the size and mass to enable installation in TNGA-K platform (same as Mid-Size sedan). 4 . R educe NV to enhance customer experience.3.  Main Characteristics and Performances Figure 1 shows the main cross section of P810. Table 1 shows the comparative main specifications of the new P810 and the previous P313 for Mid-Size SUV.  FIGURE 1   P810 main cross section.© SAE International.Downloaded from SAE International by Tsinghua University, Saturday, April 25, 2020DEVELOPMENT OF NEW HYBRID TRANSAXLE FOR MID-SIZE SPORTS UTILITY VEHICLES 2 Structure of P810 follows that of the new generation Toyota Hybrid System (THS). Its structure is described below [ 5]: •U tilizing a four-axis gear train configuration, the transaxle is composed of a torsional damper with torque limiter, input shaft, power split planetary gear, generator, motor, reduction gear, differential gear, and the casing which is comprised of a housing, case and rear cover. •D ual-axle motor structure and the motor speed reduction device is in parallel shaft gear layout. •L ubrication is conducted through the transaxle by pumping up oil onto the gears and bearings by differential gear rotation. The adoption of this new generation THS structure for P810 resulted in a 25% reduction in mechanical loss compared to that of P313. When compared to P313, P810 increased output torque by 10% in EV mode even though motor torque was reduced by 19%. This was achieved by increasing gear ratio by 36% and increasing motor speed. This allowed P810 to reduce mass by 6% compared to P313. 4.  Overall Length Short ening Structure Motor torque for the Mid-Size SUV oriented P810 has been increased by 51% compared with the Mid-Size sedan oriented P710. However, due to the increase in width of