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Secondary air system in an exhaust gas purification system of an internal combustion engine

  • US 10,443,475 B2
  • Filed: 09/16/2015
  • Issued: 10/15/2019
  • Est. Priority Date: 10/14/2014
  • Status: Active Grant
First Claim
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1. A method for operating a multi-cylinder internal combustion engine, the method comprising:

  • monitoring a pressure in a secondary air system with which secondary air is introduced into exhaust of the internal combustion engine wherein individual cylinders of the internal combustion engine are associated with one of at least two cylinder banks and a separate exhaust duct is associated with each cylinder bank;

    delivering secondary air to the at least two cylinder banks using a compression arrangement via a common secondary air line divided into a number of individual secondary air sublines corresponding to the number of exhaust ducts at a branching point downstream of the compression arrangement;

    controlling flow of the secondary air to enable or inhibit the flow using a throughflow control arrangement in each of the individual secondary air sublines;

    detecting values for the pressure using a pressure sensor downstream of the compression arrangement and upstream of the branching point;

    detecting pressure pulsations of a pressure in each cylinder bank when the compression arrangement is activated and the throughflow control arrangement set into the open state;

    summing the detected pressure pulsations;

    comparing each the cylinder bank-specific summed-up values with threshold values; and

    if the respective threshold value is exceeded, identifying a fault in the throughflow control arrangement, the fault comprising an arrangement that is not opened or not fully opened, or a blockage, or a leak in the corresponding secondary air subline and adjusting operation of the internal combustion engine using a cylinder bank-specific entry in a fault memory of a control device corresponding to the identified fault.

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