Torotrak (development) Limited

Matthew Piers Burke

Matthew Gibson Field

Stephen William Murray

The invention is concerned with control of a motor vehicle powertrain having a transmission of torque-controlled type. The powertrain also has an engine which provides a controllable engine torque. The method involves determining a reaction torque requirement and an engine torque requirement suitable to create a desired wheel torque and also a desired engine acceleration. The engine torque and the reaction torque provided by the transmission are set accordingly. The invention is characterized by the fact that the aforementioned calculation involves estimating and allowing for vehicle acceleration.

Method for controlling a motor vehicle powertrain

A method for controlling a continuously variable ratio transmission is described. The method may include controlling a continuously variable ratio unit ('variator') having rotary input and output members through which the variator is coupled between an engine and a driven component, the variator receiving a primary control signal and being constructed and arranged to exert upon its input and output members torques which correspond directly to the control signal. The method may also include determining a target engine acceleration, determining settings of the variator's primary control signal and of an engine torque control for providing the required engine acceleration and adjusting the control signal and/or the engine torque control based on these settings, predicting a consequent engine speed change, allowing for engine and/or transmission characteristics, and correcting the settings of the control signal and engine torque based on a comparison of actual and predicted engine speeds.

Method of controlling a continuously variable transmission

The invention concerns a method of operating a motor vehicle powertrain comprising an infinitely variable transmission and an engine. The transmission comprises a rotary transmission input coupled to the engine, a rotary transmission output coupled to the vehicle wheels, a variator which provides a continuously variable ratio (the 'variator ratio'), and gearing for coupling the variator between the engine and the transmission output in such a manner that the ratio of transmission output speed to transmission input speed (the 'reciprocal transmission ratio') is a function of the variator ratio. The available range of variator ratios maps onto both forward and reverse reciprocal transmission ratios, and at a particular variator ratio (the &#x201c;geared neutral ratio&#x201d;) the transmission output is stationary despite its being coupled through the transmission to the rotating transmission input. The comprises sustaining engine speed in a range of low reciprocal transmission ratios containing and extending to either side of geared neutral, by applying a drive torque demand to the engine even while the powertrain is operating in overrun.

Powertrain control method and system

There is described a method of controlling a continuously variable ratio transmission of the type comprising a continuously variable ratio unit ('variator') which has rotary input and output members though which the variator is coupled between an engine and a driven component, the variator receiving a primary control signal and being constructed and arranged such as to exert upon its input and output members torques which, for a given variator drive ratio, correspond directly to the control signal, the method comprising: determining a target engine acceleration, determining settings of the variator's primary control signal and of an engine torque control for providing the required engine acceleration and adjusting the control signal and/or the engine torque control based on these settings, predicting a consequent engine speed change, allowing for engine and/or transmission characteristics, and correcting the settings of the control signal and engine torque based on a comparison of actual and predicted engine speeds.

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Clitheroe, United Kingdom

Matthew Piers Burke