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A control system and method for a power delivery system, such as that of an automotive vehicle, having an engine coupled to a continuously variable ratio transmission (CVT). Independent control of engine and transmission enable the engine to precisely follow a desired operating characteristic, such

A control system and method for a power delivery system, such as that of an automotive vehicle, having an engine coupled to a continuously variable ratio transmission (CVT). Independent control of engine and transmission enable the engine to precisely follow a desired operating characteristic, such as the ideal operating line for low fuel consumption. Engine fuel requirements (e.g., throttle position) are a function of at least measured engine speed, and are adjusted in accordance with any load placed on the engine so that, during low power operation, fuel flow is increased when a decrease in operating speed occurs, and fuel flow is reduced when an increase in operating speed occurs. The speed of the engine is therefore regulated in accordance with the load placed thereon. Reduction of transmission ratio effects vehicle acceleration in this mode, while an increase in transmission ratio effects vehicle deceleration. Where a clutch or other type of variable engagement coupling is employed, the engine still is independently regulated in accordance with the fuel function even when the clutch is slipping. During the clutch slipping phase, the transmission preferably is held at a substantially constant high reduction ratio, while vehicle acceleration and deceleration are effected simply by varying the degree of engagement of the clutch.

대표청구항 ▼

A method of controlling the low power operation of a power delivery system including a prime mover and a continuously variable ratio transmission coupled to the prime mover for delivering power from the prime mover to an output shaft, the prime mover having fuel delivery means for delivering a varia

A method of controlling the low power operation of a power delivery system including a prime mover and a continuously variable ratio transmission coupled to the prime mover for delivering power from the prime mover to an output shaft, the prime mover having fuel delivery means for delivering a variable quantity of fuel thereto, the method comprising the steps of: measuring the speed of the prime mover; predetermining a fuel function defining desired fuel requirements for the prime mover in relation to at least prime mover operating speed, said fuel function prescribing an increased fuel flow for a decrease in measured operating speed and a reduced fuel flow for an increase in measured operating speed; controlling the fuel delivery means only in accordance with said fuel function, whereby the speed of the prime mover is regulated in accordance with the load placed thereon; and commanding desired performance of the power delivery system by reducing the transmission ratio to command an increase in power output and increasing the transmission ratio to command a reduction in power output.