Patent ID: 7294938

Claim:
A method of controlling a vehicle driving system; (A) by accumulating an output power of an engine operating intermittently in a flywheel interlocked with the engine as rotational energy, transmitting the output power of the engine or the accumulated energy to an output shaft by way of a power transmission system to drive the output shaft and drive wheels of vehicle interlocked with the output shaft to rotate, (B) the power transmission system; (a) having a first motor generator, a differential gear and a second motor generator, (b) the first motor generator having a stator and a rotor, the differential gear having an input shaft, an outlet shaft, a reactionary shaft and a plurality of mutually engaging gears, the second motor generator being adapted to receive the output electric power of the first motor generator, (c) one of the input shaft, the outlet shaft and the reactionary shaft of the differential gear being interlocked with the flywheel and the engine, another one of the input shaft, the outlet shaft and the reactionary shaft being interlocked with the output shaft, the remaining one of the input shaft, the outlet shaft and the reactionary shaft being interlocked with the rotor of the first motor generator, (d) the second motor generator being interlocked with the drive wheels interlocked with the output shaft or other drive wheels, (C) all the electric power generated by the first motor generator being supplied to the second motor generator and subjected to basic control of indicating the value of drive torque T 2 to the output shaft to control the speed of the vehicle provided that the second motor generator is interlocked with the output shaft, (D) determining the torque Trd by the relation of Trd =( ec− 1)× T 2 ×ηmr/[{ηmo −(η mr×ηe )}+{( ec×Nf/N 2)×η mr×ηe}], where {circle around (1)}Trd is a torque of the reactionary shaft, {circle around (2)}ηmr is a power transmission efficiency from the input shaft to the reactionary shaft by way of the differential gear, {circle around (3)}ηmo is a power transmission efficiency from the input shaft to the output shaft by way of the differential gear, {circle around (4)}ηe is a power transmission efficiency from the reactionary shaft to the output shaft by way of the first motor generator and the second motor generator, while {circle around (5)}ec is a critical speed ratio of the differential gear, {circle around (6)}N 2 is a rotational speed of the output shaft, and {circle around (7)}Nf is a rotational speed of the flywheel, and (E) controlling generation of electric power of the first motor generator so as to cause the reactionary shaft to produce the torque Trd.