Abstract: An automatic transmission with a torque converter for use with an internal combustion engine in which the ignition timing is changed over to an advancing timing region or a retarding timing region in response to the operating condition of the engine. Two different speed shifting characteristics are provided in response to whether the ignition timing is in the advancing timing region or in the retarding timing region. In addition, the two speed shifting characteristics are changed over to each other according to the two ignition timing characteristics.

Abstract: A governor valve assembly is disclosed for automatic transmission units including first and second valve members which are provided in a rotating governor body so as to be telescopically fitted together. The first and second valve members are arranged on diametrically opposite sides of the rotating axis of the governor body, and cooperate with one another so that when the rotating speed of the governor body reaches a preselected level, a governor pressure is produced and delivered from the assembly.

Abstract: An emission control system for a motor vehicle equipped with an automatic transmission having a band servo system including switching means for detecting the state of the band servo system and two vehicle speed switches respectively susceptible to two different vehicle speeds V.sub.1 and V.sub.2 (V.sub.1 <V.sub.2). The emission control system includes means for enriching the air-fuel ratio of the air-fuel mixture in an intake passage of the engines and exhaust gas recirculating means are so arranged that the air-fuel ratio of the air-fuel mixture is normally set on the rich side and the EGR ratio is made high. Correspondingly in the high driving range with a vehicle speed of lower the V.sub.2 the EGR ratio is made low, and in the high driving range with a vehicle speed of at least V.sub.2 the EGR ratio is made low and the air-fuel ratio is released from being set on the rich side.