System and method for reducing engine knock

Patent metadata

Field	Value
Publication number	US-11067014-B2
Application number	US-201816036056-A
Country	US
Kind code	B2
Filing date	Jul 16, 2018
Priority date	Jul 31, 2012
Publication date	Jul 20, 2021
Grant date	Jul 20, 2021

Abstract

A method includes operating a spark ignition engine and flowing low pressure exhaust gas recirculation (EGR) from an exhaust to an inlet of the spark ignition engine. The method includes interpreting a parameter affecting an operation of the spark ignition engine, and determining a knock index value in response to the parameter. The method further includes reducing a likelihood of engine knock in response to the knock index value exceeding a knock threshold value.

First claim

What is claimed is:

1. A system comprising:
a spark-ignition internal combustion engine having an intake system structured to deliver induction gas to an intake manifold of the engine, a fuel system structured to provide a mixed fuel and air charge to a combustion chamber of the engine, and an exhaust system including a three-way catalyst;
a compressor coupled to an inlet of the intake system;
a low pressure exhaust gas recirculation (EGR) system structured to recirculate exhaust gas to the intake system at least from an intermediate position of the three-way catalyst; and
an electronic control unit (ECU) configured to determine a knock index value and recirculate exhaust gas to the intake system with the low pressure EGR system to reduce a likelihood of engine knock in response to the knock index value exceeding a knock threshold value.

2. The system of claim 1 , further comprising a particulate filter operationally coupled to an engine exhaust system upstream of the three-way catalyst.

3. The system of claim 1 , wherein the ECU is configured to recirculate the exhaust gas when a temperature of the EGR is below a condensation limit temperature for the EGR.

4. A method, comprising:
operating a spark ignition engine;
interpreting a parameter affecting an operation of the spark ignition engine;
determining a knock index value in response to the parameter; and
flowing exhaust gas with a low pressure exhaust gas recirculation (EGR) system at least from an intermediate position of a three-way catalyst in the exhaust to an inlet of the spark ignition engine to reduce a likelihood of engine knock in response to the knock index value exceeding a knock threshold value.

5. The method of claim 4 , wherein the flowing exhaust gas with the low pressure EGR system reduces an intake manifold temperature of the spark ignition engine.

6. The method of claim 5 , further comprising bypassing at least a portion of compressor outlet gases and at least partially bypassing an EGR cooler to reduce the intake manifold temperature.

7. The method of claim 4 , further comprising reducing a coolant temperature for an EGR cooler while flowing exhaust gas with the low pressure EGR system.

8. The method of claim 4 , wherein flowing exhaust gas with the low pressure EGR system reduces a spark ignition engine backpressure and the low pressure EGR system is further operable to flow the exhaust gas from a location upstream of and downstream of the three-way catalyst.

9. The method of claim 4 , further comprising adjusting a valve timing for the spark ignition engine to reduce the likelihood of engine knock.

10. The method of claim 4 , further comprising at least partially fueling the spark ignition engine by direct injection to reduce the likelihood of engine knock.

11. A system comprising:
a spark-ignition internal combustion engine having an intake system configured to deliver induction gas to an intake manifold of the engine, a fuel system structured to provide a mixed fuel and air charge to a combustion chamber of the engine, and an exhaust system including a three-way catalyst;
a compressor coupled to an inlet of the intake system and providing a compressed air stream;
a low pressure exhaust gas recirculation (EGR) system configured to recirculate exhaust gas at least from an intermediate position of the three-way catalyst to the intake system upstream of the compressor;
a charge-air-cooler (CAC) structured to cool at least a portion of the compressed air stream, the CAC including a variable cooling performance device;
an electronic control unit (ECU) structured to:
interpret a parameter affecting an operation of the engine;
determine a knock index value in response to the parameter; and
provide an engine control command in response to the knock index value exceeding a knock threshold value;

wherein the low pressure EGR system and the variable cooling performance device are responsive to the engine control command to reduce a likelihood of engine knock in response to the knock index value exceeding a knock threshold value.

12. The system of claim 11 , wherein the variable cooling performance device comprises a variable coolant side effective flow area device for the CAC and the variable coolant side effective flow area device comprises a coolant inlet position control device.

13. The system of claim 11 , wherein the variable cooling performance device comprises a variable coolant side effective flow area device for the CAC and the variable coolant side effective flow area device comprises a coolant outlet position control device.

14. The system of claim 11 , wherein the variable cooling performance device comprises a variable coolant side flow rate device.

15. The system of claim 11 , wherein the variable cooling performance device comprises a compressed air stream inlet position control device.

16. The system of claim 11 , wherein the wherein the variable cooling performance device comprises a compressed air stream outlet position device.

17. The system of claim 11 , wherein the variable cooling performance device comprises a means for providing a reduced cooling effectiveness in the CAC, the means including cooling the entire compressed air stream.

18. The system of claim 17 , wherein the ECU is further structured to provide the reduced cooling effectiveness in response to a condensation temperature of the compressed air stream.

19. The system of claim 11 , wherein the ECU is further structured to interpret a condensation temperature of the compressed air stream, and wherein the providing the engine control command is further in response to the condensation temperature.

Assignees

• Cummins Inc

Inventors

• Dane Marten H
• Kolhouse J Steven
• Yonushonis Thomas M
• Wills J Stephen
• Geckler Samuel C

Classifications

• F02D9/04

  concerning exhaust conduits (throttle valves, or arrangements thereof in conduits F02D9/08) · CPC title

• F02M26/28

  with liquid-cooled heat exchangers · CPC title

• F02D2200/0402

  the parameter being determined by using a model of the engine intake or its components · CPC title

• F02D41/0007

  for control of turbo-charged or super-charged engines (control of the pumps per se F02B37/12) · CPC title

• F02M26/25

  with coolers having bypasses · CPC title