Method for monitoring the secondary air system in an exhaust-gas purification system
First Claim
1. 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, whereinthe 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 operableto 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, andto differentiate the fault location with regard to the respective cylinder bank as a function of the result of the comparison.
2 Assignments
0 Petitions
Accused Products
Abstract
The individual cylinders of the internal combustion engine are divided into at least two cylinder banks wherein each is assigned a separate exhaust-gas channel. Secondary air is conveyed by a compressor. The flow of the secondary-air mass flow is set independently by an electrically controllable throughflow control. A value for the entire secondary-air mass flow is determined from the signal of a secondary-air mass sensor. The throughflow control is controlled into an open position, the value for the entire secondary-air mass flow is detected and subsequently the throughflow control is controlled into a closed position, the values for the secondary-air mass flows are detected before and after closure, and these values are compared with a plurality of different threshold values and, as a function of the result of the comparisons, a determination is made of the fault location with regard to the respective cylinder bank.
16 Citations
18 Claims
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1. 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. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method 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, the method comprising the steps of:
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subdividing the individual cylinders of the internal combustion engine into at least two cylinder banks and assigning each cylinder bank a separate exhaust gas duct, conveying secondary air with the aid of a compressing means and introducing 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, adjusting the flow rate of the secondary air mass flow with the aid of electrically controllable flow control means in each of the individual secondary air lines independently of each other for the purpose of introducing secondary air mass flows on an individual cylinder bank basis, determining a value for the total secondary air mass flow that is introduced into the exhaust gas ducts from the signal of a secondary air mass meter, actuating the flow control means into an open position, recording the value for the total secondary air mass flow, actuating the flow control means into a closed position individually at time intervals relative to one another, recording the values for the secondary air mass flows occurring thereby before and after the closing of the individual flow control means, comparing said values with a plurality of different threshold values, and making a differentiation of the fault location with regard to the respective cylinder bank as a function of the result of the comparisons. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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Specification