In today’s hybrid vehicle market the Toyota Prius drive system is currently considered the
leader in electrical, mechanical, and manufacturing innovations. It is significant that in today’s
marketplace Toyota is able to manufacture and sell the vehicle for a profit.
This project’s objective is to analyze and study the Prius drive system to understand the
design and manufacturing mechanisms Toyota utilized to achieved their performance and cost
During the course of this research effort ORNL has dissected both the 2003 and 2004
Toyota/Prius drive motors. This study is focused primarily on motor design considerations and
an assessment of manufacturing issues.
Figure 1 shows the assembly of the Toyota/Prius hybrid THS II drive train system. The
motor occupies a large portion of the drive train. Studying and analyzing the motor in detail can
accomplish a through understanding of the design and manufacturing considerations of the drive
Figure 2 compares the output power and torque versus speed of the 2003 (THS) and 2004
(THS II) model Prius motors. Both the power and the torque of the motor are significantly
increased in the 2004 model.
The power at base speed of the 2004 model, as tabulated in Table 1, is 50 kW, which is
significantly higher than the 33 kW of the older model. The 400 Nm torque of the 2004 model is
also higher than the 350/305 Nm of the 2003 model.
Download full Report from http://www.ornl.gov/~webworks/cppr/y2001/rpt/120761.pdf