US 4,107,776 AGranted

Vehicle power transmission arrangements and electronic power controls

AssigneeU.S. Philips Corporation

InventorJulian R. A. Beale

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Abstract

An electronically controlled transmission arrangement for an internal combustion engine driven vehicle such as a private automobile, permitting operation under normal conditions close to regions of minimum specific fuel consumption while also permitting bringing an engine in poor operating condition close to its maximum power speed. A transmission including a continuously variable gearing is controlled by an electronic microprocessor in response to signals representing driver-selected power-command, engine-speed, and drive shaft speed. The transmission is controlled so that the engine vehicle combination operates along an engine power-load line selected according to the power command. Transition circuitry prevents a sudden change in power-command from causing the transmission to alter its ratio so quickly that there is a transient change of delivered torque in the wrong direction.

Claims19

Dependent claims

A power arrangement for a wheeled vehicle having a drive shaft, said arrangement comprising an engine, continuously variable gearing between the engine and the drive shaft, power-command means operable by a vehicle driver to command a variation in engine power, and electronic control means for varying the torque transmitted by the continuously variable gearing,

said control means being responsive to the engine speed w.sub.e, the drive shaft speed w.sub.d and the extent of actuation R.sub.a of the power command means such that the torque transmitted to the drive shaft is a different function of engine speed w.sub.e for different values of R.sub.a, said different functions corresponding to different power-load lines on an engine-power engine-speed graph, and
said control means including means, responsive to increased actuation R.sub.a of the power-command means, for causing transition between a previous power-load line and a higher-engine-speed power-load line while maintaining transmitted power at least as high as the previous level of power, and responsive to reduced actuation R.sub.a of the power-command means, for causing transition between a previous power-load line and a lower-engine-speed power-load line while maintaining transmitted power at least as low as the previous level.

A power arrangement for a wheeled vehicle having a drive shaft, said arrangement comprising an engine, transmission means for coupling the engine to the drive shaft, said transmission means including continuously variable gearing, power-command means operable by a vehicle drive for demanding a variation in engine power, sensor means for providing signals indicative of the entrance speed w.sub.e, the drive shaft speed w.sub.d and the extent of actuation R.sub.a of the power command means, actuator means for regulating the torque transmitted by said gearing, and

electronic control means for receiving from said sensor means inputs indicative of w.sub.e, w.sub.d and R.sub.a and for providing control signals to said actuator means responsive to said inputs for determining the torque transmitted to the drive shaft in accordance with the power produced by the engine as a function of the engine speed w.sub.e and one of a plurality of power-load lines for the engine, said load lines corresponding to respective extents of actuation R.sub.a of the power-command means such that for increasing values of R.sub.a the load line selected occurs at higher engine speeds w.sub.e ;
said control means including means for causing transition responsive to increased actuation R.sub.a between the previously selected power-load line and a higher engine speed power-load line while maintaining transmitted power at least as high as the previous level of power, and in response to reduced actuation R.sub.a causing transition between the previous power-load line and a lower engine speed power-load line while maintaining transmitted power at least as low as the previous level.

Dependencies are inferred from the claim text.