Patent ID: 8024108

Claim:
A device for monitoring the secondary air system of a multi-cylinder internal combustion engine by means of which secondary air is introduced into the exhaust gas of the internal combustion engine, wherein the internal combustion engine has at least two cylinder banks, to each of which a specific number of cylinders of the internal combustion engine are assigned and each individual cylinder bank has a separate exhaust gas duct, a compressing means is provided that conveys secondary air and introduces the secondary air into the respective exhaust gas ducts by way of a number of individual secondary air lines corresponding to the number of exhaust gas ducts, and comprising: in each case a flow control means controllable independently of each other by means of signals of a control device in each of the individual secondary air lines for the purpose of introducing secondary air mass flows on an individual cylinder bank basis, an air mass meter from the signal of which a value is determined for the total secondary air mass flow that is introduced into the exhaust gas ducts, wherein the control device is operable to actuate the flow control means into an open position, to record the value for the total secondary air mass flow, to then actuate the flow control means into a closed position individually at time intervals relative to one another, to record the values for the secondary air mass flows occurring thereby before and after the closing of the individual flow control means, to compare said values with a plurality of different threshold values, and to differentiate the fault location with regard to the respective cylinder bank as a function of the result of the comparison.