A High Torque, High Efficiency CVT for Electric Vehicles

Epilogics, a young engineering firm in Los Gatos, CA, has developed the first fully geared, high torque, high efficiency, infinitely variable transmission suitable for automotive applications. The IVT has particular significance to electric vehicles because it can provide a highly efficient, yet exceptionally controllable means to regenerate power throughout the normal braking cycle (allowing regeneration even at near-zero vehicle speeds). Under normal operating conditions, the efficiency of the Epilogics transmission exceeds 90% as derived mathematically and corroborated experimentally. The device does not rely on traction to transmit torque and can therefore match the torque capacity of any typical gear drive. The size, weight, and cost of the device closely approximates that of a four-speed transmission suitable for the application. A recent development allows a bi-directional transmission which greatly enhances its attractiveness as an electric vehicle transmission by providing for a highly desirable (albeit, unnecessary in itself) means to regulate vehicle speed independently of motor speed, in addition to a means to a highly practicable regenerative braking system.