Method for operating an internal combustion engine employing a dedicated-cylinder egr system

Patent metadata

Field	Value
Publication number	US-2016160772-A1
Application number	US-201414560568-A
Country	US
Kind code	A1
Filing date	Dec 4, 2014
Priority date	Dec 4, 2014
Publication date	Jun 9, 2016
Grant date	—

Abstract

A multi-cylinder spark-ignition internal combustion engine (engine) that includes a dedicated-cylinder exhaust gas recirculation (EGR) system is described. The dedicated-cylinder EGR system includes a controllable exhaust gas diverter valve that selectively diverts all exhaust gas produced by one of the cylinders to an air intake system of the engine. A method for controlling the engine includes monitoring a parameter associated with operation of the dedicated-cylinder EGR system. Upon detecting a change in the parameter that indicates a change in operation of the dedicated-cylinder EGR system, a controller controls operation of the internal combustion engine to reduce an effective cylinder compression ratio.

First claim

1 . A method for operating a multi-cylinder spark-ignition internal combustion engine that includes a dedicated-cylinder exhaust gas recirculation (EGR) system, the dedicated-cylinder EGR system including a controllable exhaust gas diverter valve that selectively diverts all exhaust gas produced by one of the cylinders to an air intake system of the engine, the method comprising:
monitoring a parameter associated with operation of the dedicated-cylinder EGR system; and upon detecting a change in the parameter indicating a change in operation of the dedicated-cylinder EGR system, controlling, by a controller, operation of the internal combustion engine to reduce an effective cylinder compression ratio.

2 . The method of claim 1 , wherein the internal combustion engine further includes a variable intake valve activation system; and wherein controlling operation of the internal combustion engine to reduce the effective cylinder compression ratio comprises controlling the variable intake valve activation system to implement a late intake valve closing control strategy.

3 . The method of claim 2 , wherein controlling the variable intake valve activation system to implement the late intake valve closing control strategy comprises controlling the variable intake valve activation system to adjust cam phasing to delay closing of the intake valve.

4 . The method of claim 3 , wherein controlling the variable intake valve activation system to implement the late intake valve control strategy comprises controlling the variable intake valve activation system to increase an intake valve open period.

5 . The method of claim 1 , wherein the internal combustion engine further includes a variable intake valve activation system; and wherein controlling operation of the internal combustion engine to reduce the effective cylinder compression ratio comprises controlling the variable intake valve activation system to implement an early intake valve closing control strategy.

6 . The method of claim 5 , wherein controlling the variable intake valve activation system to implement the early intake valve control strategy comprises controlling the variable intake valve activation system to reduce an intake valve open period.

7 . The method of claim 6 , wherein controlling the variable intake valve activation system to reduce an intake valve open period comprises controlling magnitude of valve lift of the intake valves to a low-lift valve open position.

8 . The method of claim 1 , wherein monitoring a parameter associated with operation of the dedicated-cylinder EGR system comprises directly monitoring operation of a component of the dedicated-cylinder EGR system.

9 . The method of claim 8 , wherein directly monitoring operation of a component of the dedicated-cylinder EGR system comprises monitoring operation of the controllable exhaust gas diverter valve.

10 . The method of claim 1 , wherein monitoring a parameter associated with operation of the dedicated-cylinder EGR system comprises monitoring operation of a system that is influenced by the operation of the dedicated-cylinder EGR system.

11 . The method of claim 10 , wherein monitoring operation of a system that is influenced by the operation of the dedicated-cylinder EGR system comprises monitoring the air intake system of the engine.

12 . The method of claim 1 , wherein detecting a change in the parameter indicating a change in operation of the dedicated-cylinder EGR system comprises detecting a change in the parameter indicating degradation in operation of the dedicated-cylinder EGR system.

13 . A method for operating a high compression ratio multi-cylinder internal combustion engine that includes a variable intake valve activation system and a dedicated-cylinder exhaust gas recirculation (EGR) system, the dedicated-cylinder EGR system including a controllable exhaust gas diverter valve that selectively diverts all exhaust gas produced by at least one of the cylinders to an air intake system of the engine, the method comprising:
monitoring a parameter associated with operation of the dedicated-cylinder EGR system; and controlling, by a controller, the variable intake valve activation system to reduce an effective cylinder compression ratio when a change in the parameter associated with operation of the dedicated-cylinder EGR system indicates a degradation in operation of the dedicated-cylinder EGR system.

14 . The method of claim 13 , wherein controlling the variable intake valve activation system to reduce the effective cylinder compression ratio comprises implementing a late intake valve closing control strategy.

15 . The method of claim 14 , wherein implementing the late intake valve closing control strategy comprises controlling the variable intake valve activation system to adjust cam phasing to delay closing of the intake valve.

16 . The method of claim 15 , wherein controlling the variable intake valve activation system to reduce the effective cylinder compression ratio comprises increasing an intake valve open period.

17 . The method of claim 14 , wherein controlling the variable intake valve activation system to reduce the effective cylinder compression ratio comprises implementing an early intake valve closing control strategy.

18 . The method of claim 14 , wherein controlling the variable intake valve activation system to reduce the effective cylinder compression ratio comprises reducing an intake valve open period.

19 . The method of claim 18 , wherein reducing the intake valve open period comprises controlling magnitude of valve lift of the intake valves to a low-lift valve open position.

20 . A high-compression-ratio multi-cylinder spark-ignition internal combustion engine, comprising:
a dedicated-cylinder exhaust gas recirculation (EGR) system, the dedicated-cylinder EGR system including a controllable exhaust gas diverter valve that selectively diverts all exhaust gas produced by at least one of the cylinders to an air intake system of the engine; a variable intake valve activation system; and a controller including an executable routine, the executable routine including:
monitoring a parameter associated with operation of the dedicated-cylinder EGR system; and
controlling operation of the internal combustion engine to reduce an effective cylinder compression ratio upon detecting a change in the parameter indicating a degradation in operation of the dedicated-cylinder EGR system.

Assignees

• Gm Global Tech Operations Inc

Inventors

• Keating Edward J

Classifications

• F02D13/0203

  Variable control of intake and exhaust valves · CPC title

• F02D41/26

  using computer, e.g. microprocessor · CPC title

• F02D41/0065

  Specific aspects of external EGR control (constructional details of EGR system F02M26/00) · CPC title

• F02D15/00

  Varying compression ratio · CPC title

• F02D41/0007

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