Continuously Variable Transmission Control System for Toyota Intelligent Idling Stop System

As requirements for protecting the global environment are being heightened on a worldwide scale in recent years, the development of low fuel consumption technologies in order to inhibit the discharge of CO₂ is an important issue for the automotive industry.

Recently, Toyota has developed a Super CVT for the 1.3-to 1.5-liter class vehicles to further improve their fuel economy. This CVT has been adopted on vehicles equipped with the ‘idling stop system’. The ‘idling stop system’ automatically stops the engine when the vehicle is stopped and the transmission shift lever is in the ‘D’ position (e.g. when the vehicle is at a stoplight). This improves the fuel economy of the vehicle by eliminating fuel consumption while the vehicle is stopped. The conventional CVT poses unique conditions such as startoff time lag or shock after the engine is restarted. These conditions occur because the CVT oil pump cannot generate hydraulic pressure while the engine is stopped. To solve these problems, the Super CVT system has been developed in order to optimally control the hydraulic pressure while the engine is being stopped automatically. This is accomplished through the use of an electric oil pump in addition to the conventional CVT oil pump. As a result, this system ensures convenient and reliable operation when the engine is restarted.