Patent ID: 6390038
Filing Date: 2002-05-21
Classification: F01L

Abstract:
Method for protection against overheating of electromagnetic actuators for actuation of intake and exhaust valves in internal-combustion engines, in which an actuator (1) of an engine (20) is connected to a respective intake or exhaust valve (2), and comprises a mobile unit (3) which is actuated magnetically, in order to control the movement of the said valve (2), and a first and a second electromagnet (6a, 6b), which are disposed on opposite sides of the said mobile unit (3); the said actuator (1) also being connected to a control unit (11), via piloting means (12), which supply at least one current (I1, I2), and to current-measuring means (13); the said current-measuring means supplying to the said control unit (11) measured values (IM1, IM2) of the said at least one current (I1, I2);the method being characterised in that it comprises the steps of: a) estimating (120) for each of the said first and second electromagnets (6a, 6b), a temperature value TK+1 which is updated on the basis of a present temperature value TK and of the said measured values (IM1, IM2) of the said at least one current (I1, I2); and b) checking (140) whether the updated temperature value TK is lower than a first threshold (TS1); and c) implementing protective action (160), if the said updated temperature value TK is higher than the said first threshold (TS1).