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

• Current Assignee: Vitesco Technologies GmbH (INA-Holding Schaeffler GmbH & Co. KG)
• Original Assignee: Continental Automotive GmbH (Continental AG)
• Inventors: Lipa, Jaroslav
• Primary Examiner(s): Lee, Brandon D
• Application Number:
  US15/518,052
• Publication Number:
  US 20170314442A1
• Time in Patent Office: 1,490 Days
• CPC Class Codes: F01N 11/00 Monitoring or diagnostic devices for exhaust-gas treatment apparatus , e.g. for catalytic activity safety, indicating or supervising devices for internal combustion engines F02B77/08; testing of machines G01M13/00
• CPC Class Codes: F01N 13/011 having two or more purifying devices arranged in parallel
• CPC Class Codes: F01N 2250/04 afterburning and catalytic conversion
• CPC Class Codes: F01N 2270/04 for afterburning
• CPC Class Codes: F01N 2270/10 for rendering exhaust innocuous, e.g. by dilution
• CPC Class Codes: F01N 2430/06 by varying fuel-air ratio, e.g. by enriching fuel-air mixture
• CPC Class Codes: F01N 2550/14 Systems for adding secondary air into exhaust
• CPC Class Codes: F01N 2560/025 for measuring or detecting O2, e.g. lambda sensors
• CPC Class Codes: F01N 2560/07 the means being an exhaust gas flow rate or velocity meter or sensor, intake flow meters only when exclusively used to determine exhaust gas parameters
• CPC Class Codes: F01N 2560/08 the means being a pressure sensor
• CPC Class Codes: F01N 2900/0418 using integration or an accumulated value within an elapsed period
• CPC Class Codes: F01N 2900/08 said parameters being related to the engine
• CPC Class Codes: F01N 2900/104 Battery status
• CPC Class Codes: F01N 2900/1406 Exhaust gas pressure
• CPC Class Codes: F01N 3/101 Three-way catalysts
• CPC Class Codes: F01N 3/18 characterised by methods of operation; Control
• CPC Class Codes: F01N 3/20 specially adapted for catalytic conversion F01N3/22 takes precedence; Methods of operation or control of catalytic converters
• CPC Class Codes: F01N 3/2006 Periodically heating or cooling catalytic reactors, e.g. at cold starting or overheating by electrically controlling the supply of combustible mixture or its constituents only F02D41/0235
• CPC Class Codes: F01N 3/22 Control of additional air supply only, e.g. using by-passes or variable air pump drives
• CPC Class Codes: F01N 3/222 using electric valves only
• CPC Class Codes: F01N 3/225 : Electric control of additional air supply
• CPC Class Codes: F01N 3/227 : using pneumatically operated valves, e.g. membrane valves
• CPC Class Codes: F01N 3/32 : using air pump using jet air pumps F01N3/34; pumps in general F04
• CPC Class Codes: F01N 9/00 : Electrical control of exhaust gas treating apparatus monitoring or diagnostic devices for exhaust-gas treatment apparatus F01N11/00; conjoint electrical control of two or more combustion engine functions F02D43/00
• CPC Class Codes: Y02T 10/12 : Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 : Engine management systems

Abstract

The present disclosure relates to internal combustion engines. The teachings thereof may include monitoring 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. The methods may include delivering secondary air with 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 the secondary air to simultaneously enable or inhibit the flow to the individual secondary air sublines; detecting values for the pressure downstream of the compression arrangement and upstream of the branching point; detecting 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 pulsations; comparing each of summed-up values with threshold values; and if the respective threshold value is exceeded, identifying a fault in the throughflow control arrangement.

Claims

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.

2. The method as claimed in claim 1, further comprising filtering the pressure signal with a bandpass filter before summing the cylinder bank-specific pressure pulsations.

3. The method as claimed in claim 2, wherein the bandpass filter comprises an adaptive bandpass filter with cut-off frequencies dependent on a revolution rate and a battery voltage associated with an on-board electrical system of the internal combustion engine.

4. The method as claimed in claim 2, wherein the bandpass filter includes fixed cut-off frequencies determined experimentally and stored in a value memory of a control device controlling the internal combustion engine.

5. The method as claimed in claim 1, further comprising the threshold values stored in a characteristic field of a value memory of a control device controlling the internal combustion engine as a function of a cylinder fill level summed-up during the blowing in of secondary air and a coolant temperature of the internal combustion engine.

6. The method as claimed in claim 5, wherein the threshold values comprise identical values for equal geometric lengths of the secondary air sublines.

7. The method as claimed in claim 1, wherein the throughflow control arrangement comprises electrically controlled valves that are closed in the deenergized state.

8. The method as claimed in claim 1, wherein the throughflow control arrangements comprise mechanical non-return valves.

9. The method as claimed in claim 1, further comprising, in the event of a detected malfunction of a component of the secondary air system, entering a cylinder bank-specific entry in a fault memory of a control device controlling the internal combustion engine.

10. The method as claimed in claim 1, wherein the compression arrangement comprises an electrically driven secondary air pump.

11. A method for monitoring a secondary air system of a multi-cylinder internal combustion engine, with which secondary air is introduced into the exhaust gas 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, the method comprising:

delivering secondary air each cylinder bank using a compression arrangement via a common secondary air line dividing into a number of individual secondary air sublines corresponding to the number of exhaust ducts at a branching point downstream of the compression arrangement;

enabling or inhibiting the flow of the secondary air using a throughflow control arrangement in each of the individual secondary air sublines;

detecting values of a pressure by means of a pressure sensor downstream of the compression arrangement and upstream of the branching point;

identifying pressure pulsations of the pressure cylinder bank occurring with the compression arrangement turned off and the throughflow control arrangement set into the closed state;

detecting values for the ambient pressure;

calculating a pressure difference between the individual pulses of the pressure and the values for the ambient pressure cylinder bank-specifically;

summing the cylinder bank-specific pressure differences and checking whether the respective sums are not equal to zero; and

if said sums are different from zero, generating a stuck open secondary valve fault; 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.

12. The method as claimed in claim 11, wherein the throughflow control arrangement comprises electrically controlled valves that are closed in the deenergized state.

13. The method as claimed in claim 11, wherein the throughflow control arrangements comprise mechanical non-return valves.

14. The method as claimed in claim 11, further comprising, in the event of a detected malfunction of a component of the secondary air system, entering a cylinder bank-specific entry in a fault memory of a control device controlling the internal combustion engine.

15. The method as claimed in claim 11, wherein the compression arrangement comprises an electrically driven secondary air pump.