Patent ID: 7416045

Claim:
A modular transmission adaptable for use in a vehicle having an engine, an accelerator for indicating desired variations in vehicle velocity, a brake for indicating desired reductions in vehicle velocity, and an output drive for driving the wheels of the vehicle, said transmission comprising: a plurality of hydraulic machines, each having a rotating shaft, elongated pistons that reciprocate within cylinders formed in a stationary cylinder block, and an angularly adjustable swash plate, said pistons having a stroke that is variable up to a predetermined maximum by angular adjustment of said swash plate; said hydraulic machines, respectively, being (a) operable as a hydraulic pump with said respective hydraulic pump shaft being rotatable by the engine of said vehicle, (b) operable as a hydraulic motor with said respective hydraulic motor shaft being operatively connected to rotate said output drive of the vehicle, and (c) interconnected in a hydraulic closed loop; a controller for determining the relative speed of said output drive of the vehicle, said controller being operable following the initiation of operation of said vehicle engine and being responsive to: the speed of said hydraulic pump shaft; the speed of said hydraulic motor shaft; and desired variations in vehicle velocity as indicated by operation of said accelerator and said brake; and said controller determining: said angular adjustment of the swash plate of said hydraulic pump; said angular adjustment of the swash plate of said hydraulic motor; and the speed of said engine; said controller modifying the operation of said vehicle in accordance with said desired variations in vehicle velocity as indicated by operation of said accelerator and said brake while compensating for changes in vehicle load and variations in the terrain being traversed by the vehicle and automatically adjusting the speed of said engine to maximize predetermined parameters related to fuel economy.