An improved electrically variable transmission, especially useful in a hybrid electric vehicle, includes a variable input power split and independent shifting of the gear ratios of the mechanical and electrical power paths through the transmission. A first electric machine varies the ratio of the mechanical...http://www.google.com/patents/US20030032515?utm_source=gb-gplus-sharePatent US20030032515 - ELECTRICALLY VARIABLE TRANSMISSION WITH VARIABLE INPUT POWER SPLIT AND INDEPENDENT SHIFTING
