Borg-Warner Automotive Gmbh

Borg-Warner Automotive Transmission & Engine Components Corporation

Edward C Siemon

Stanley B Quinn, Jr

Alan L Miller

A camshaft (126) has a vane (160) secured to an end thereof for non-oscillating rotation therewith. The camshaft also carries a sprocket (132) which can rotate with the camshaft but which is also oscillatable with the camshaft. The vane has opposed lobes (160a, 160b) which are received in opposed recesses (132a, 132b), respectively, of the sprocket. The recesses have greater circumferential extent than the lobes to permit the vane and sprocket to oscillate with respect to one another, and thereby permit the camshaft to change in phase relative to a crankshaft whose phase relative to the sprocket is fixed by virtue of a chain drive extending therebetween. The camshaft tends to change in reaction to pulses which it experiences during its normal operation, and it is permitted to change only in a given direction, either to advance or retard, by selectively blocking or permitting the flow of hydraulic fluid, preferably engine oil, through the return lines (194, 196) from the recesses by controlling the position of a vented spool (200) within a valve body (198) of a control valve (192) in response to a signal indicative of an engine operating condition from an engine control unit (208) via cable (238). The vented spool is selectively positioned within the valve body by a electromechanical actuator (201) which is controlled by the engine control unit. The spool is centered when an optimum phase angle between crankshaft and camshaft is achieved.

VCT control with a direct electromechanical actuator

A continuously variable transmission having a belt ratio measurement system. The continuously variable transmission contains a moveable sheave and a fixed sheave. The measurement system includes two tone wheels and pickups. The first tone wheel is mounted to the fixed sheave with a corresponding first pickup mounted proximate thereto. The second tone wheel is mounted to the moveable sheave with a corresponding second pickup mounted proximate thereto. The second tone wheel has angled teeth so that the signal sensed in the second pickup varies in relation to the axial position of the moveable sheave. By comparing the signal sensed by the first pickup with the signal sensed by the second pickup, the axial position of the moveable sheave, and thus the belt ratio of the transmission, may be determined.

Continuously variable transmission belt ratio measurement system

A camshaft (26) has a vane (60) secured to an end thereof for non-oscillag rotation therewith. The camshaft also carries a sprocket (32) which can rotate with the camshaft but which is oscillatable with respect to the camshaft. The vane has opposed lobes 60a, 60b) which are received in opposed recesses (32a, 32b), respectively, of the sprocket. The recesses have greater circumferential extent than the lobes to permit the vane and sprocket to oscillate with respect to one another, and thereby permit the camshaft to change in phase relative to a crankshaft whose phase relative to the sprocket is fixed by virtue of a chain drive extending therebetween. The camshaft experiences pulses during its normal operation, and these pulses are used to change its phase with respect to the crankshaft. The camshaft is permitted to change only in a given direction, either to advance or retard, by selectively blocking or permitting the flow of hydraulic fluid, preferably engine oil, through the return lines (94, 96) from the recesses by using a stepper motor (134). The stepper motor serves to control the position of a spool (100) within a valve body (98) of a control valve in response to a signal indicative of an engine operating condition determined from a closed loop feedback system (108) which utilizes a predetermined set point, r (35), to dictate the desired camshaft phase angle to effectuate certain engine performance criteria.

VCT system having closed loop control employing spool valve actuated by

A camshaft (26) has a vane (60) secured to an end thereof for non-oscillag rotation therewith. The camshaft also carries a sprocket (32) which can rotate with the camshaft but which is oscillatable with the camshaft. The vane has opposed lobes (60a, 60b) which are received in opposed recesses (32a, 32b), respectively, of the sprocket. The recesses have greater circumferential extent than the lobes to permit the vane and sprocket to oscillate with respect to one another, and thereby permit the camshaft to change in phase relative to a crankshaft whose phase relative to the sprocket is fixed by virtue of a chain drive extending therebetween. The camshaft tends to change in reaction to pulses which it experiences during its normal operation, and it is permitted to change only in a given direction, either to advance or retard, by selectively blocking or permitting the flow of hydraulic fluid, preferably engine oil, through the return lines (94, 96) from the recesses by controlling the position of a spool (100) within a valve body (98) of a control valve in response to a signal indicative of an engine operating condition determined from a closed loop feedback system.

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Ithaca, NY, United States of America

Edward C Siemon