Patent ID: 6546789
Filing Date: 2003-04-15
Classification: F02B,F02D,Y02T

Abstract:
A method for monitoring the operation of an intake-manifold flap of an intake manifold of an internal combustion engine, the intake manifold accommodating said intake-manifold flap therein and being provided to conduct an air mass flow (ms) to the cylinders of said engine and being arranged between an air intake pipe holding a throttle flap and the inlet valves of said cylinders, wherein a change of intake manifold flap position changes the resonance characteristics of the intake manifold to achieve optimal low speed torque and high rated output at maximum engine speed and the engine having an engine rpm (nmot) when running, the method comprising the steps of:measuring the engine rpm (nmot) utilizing an rpm sensor; measuring the air mass flow (ms) utilizing an air mass flow sensor; computing the intake manifold pressure (ps) based on said engine rpm (nmot) and said air mass flow (ms) for at least two different intake-manifold flap positions corresponding to respectively different geometries of said intake manifold and respectively different ones of said resonance characteristics and, simultaneously, measuring said intake-manifold pressure utilizing pressure-detecting means; forming a difference between the computed and measured intake-manifold pressures for each one of said at least two different positions of said intake-manifold flap; and, making a diagnosis of the operation of said intake-manifold flap by evaluating the differences formed.