Description & Operation: Introduction

Transaxle is an Electronically Controlled Continuously Variable Transaxle (ECVT) which is used for seamless, stepless acceleration and deceleration. The continuously variable function in this transaxle is achieved through a power split device known as a simple compound planetary gear set, as well as motor generators No. 1 and No. 2. It is through these motor generators and the planetary gear set that the continuously variable ratio occurs. At times, this planetary assembly is used to drive the vehicle, charge the high voltage battery, or both (power split device).

An inverter, located in engine compartment, converts electrical power between the DC battery and the 3-phase alternating current (AC) voltage from 2 motor generators in transaxle. The inverter also transmits information to a computer called the High Voltage Electronic Control Unit (HVECU). Motor generator No. 1 is used to recharge high voltage battery and supply electrical power to motor generator No. 2. It also regulates the amount of electrical power supplied to motor generator No. 2 through the inverter, which varies motor generator No. 2 speed, effectively controlling the continuously variable ratio function of the transaxle. Motor generator No. 2 always drives the wheels except during deceleration, at which time the wheels are driving motor generator No. 2, which is generating electricity to be stored in high voltage battery. If the vehicle is moving forward or backward under power, motor generator No. 2 is driving the wheels.

Gearshift lever gear positions are: Park ("P"), Reverse ("R"), Neutral ("N"), normal driving position ("D") and engine braking position ("B"), which is used to assist in deceleration of vehicle during high speed (down hill) driving. Transaxle has a shift lock system to minimize the possibility of incorrect operation. Transaxle may only be shifted out of Park when brake pedal is depressed, and ignition switch is in the ON position, and gearshift lever lock release button is depressed. For additional information on shift and key interlock systems, see appropriate SHIFT INTERLOCK SYSTEMS article.