The trophy awarded in Pixar’s Cars racing series is called the Piston Cup.
The Piston Cup is the championship trophy contested by Lightning McQueen and the other stock cars in Cars. The first film’s climax centers on a three-way tie involving McQueen, Chick Hicks, and The King, forcing a final race to determine the champion.
The name echoes the Winston Cup, the former name of NASCAR’s premier stock-car championship. Pixar changed the wording to fit its fictional vehicle world while preserving the feel of an American racing institution. The Piston Cup also appears in later films and franchise merchandise.
Dinoco is a sponsor associated with the trophy and with The King, but Dinoco is not the trophy’s name. Rust-eze is McQueen’s sponsor at the beginning of the original film. Those brand names are common sources of confusion when identifying the championship award.