A radically different scheme known as continuously variable transmission (CVT) has lurked in the background for 50 years, however, and has recently made inroads in small and midsize cars and in hybrid vehicles.

• 另有一种截然不同的设计，称为无段自动变速系统（CVT），50年来一直鲜少被注意，最近开始出现在中小型汽车和混合动力车辆上。