A method for detecting a fault in a pressure sensor that measures a pressure in a hydraulic valve actuation system

摘要

A method comprising: estimating a pressure of hydraulic fluid in a valve actuation system that actuates an intake valve (122) and / or an exhaust valve (130) of an engine (102); comparing the estimated pressure with a pressure obtained by a Pressure sensor (172; 174) which is arranged in the valve actuation system and which detects a fault in the pressure sensor (172; 174) on the basis of a difference between the estimated pressure and the measured pressure; the fault in the pressure sensor (172; 174 ) is detected when the difference between the estimated pressure and the measured pressure is greater than a threshold value; wherein: the valve actuation system includes a first pump (146) and a second pump (148); the first pump (146) delivers fluid to the second pump (148) at a first pressure; andthe second pump (148) delivers fluid to a valve actuator (140, 142) at a second pressure; further comprising estimating the first pressure based on a temperature of hydraulic fluid in the valve actuation system, a speed of the first pump (146), and a mass flow rate of hydraulic fluid in the valve actuation system; the mass flow rate of hydraulic fluid in the valve actuation system is estimated; the mass flow rate of hydraulic fluid in the Valve actuation system is estimated based on the temperature of hydraulic fluid and a target pressure of hydraulic fluid in the valve actuation system; andthe mass flow rate of hydraulic fluid in the valve actuation system based on an amount by which the inlet valve (122) and / or the outlet valve (130) is or are increased, a period of time in which the inlet valve (122) and / or the outlet valve (130 ) is or are open, and a frequency with which the inlet valve (122) and / or the outlet valve (130) is / are opened is estimated.