System and method for turbocharger compressor surge control

Patent metadata

Field	Value
Publication number	US-9765712-B2
Application number	US-201414250770-A
Country	US
Kind code	B2
Filing date	Apr 11, 2014
Priority date	Apr 11, 2014
Publication date	Sep 19, 2017
Grant date	Sep 19, 2017

Abstract

An internal combustion engine having intake and exhaust manifolds, a turbocharger with a compressor, and at least one of: an exhaust gas recirculation (EGR) valve and a variable geometry turbine (VGT). The system further includes a control computer configured to determine at least one of torque demand, pressure across the compressor, and pressure gradient ratio between the exhaust manifold and the intake manifold relative to one of exhaust manifold pressure, intake manifold pressure, and 1. The control computer performs at least one of: closing the EGR valve in response to the determined at least one of torque demand, pressure across the compressor, and pressure gradient ratio, and lessening restriction provided by the variable geometry turbine responsive to the determined at least one of torque demand, pressure across the compressor, and pressure gradient between the exhaust manifold and the intake manifold.

First claim

What is claimed is:

1. A system for controlling turbocharger compressor surge, comprising:
an internal combustion engine having intake and exhaust manifolds;
a turbocharger including a compressor having an inlet fluidly coupled to ambient and an outlet fluidly coupled to the intake manifold;
an exhaust gas recirculation (EGR) valve disposed in-line with an EGR conduit fluidly coupled between said intake and exhaust manifolds, said EGR valve responsive to an EGR valve control signal to control exhaust gas flow therethrough;
a variable geometry turbine (VGT) fluidly coupled to the exhaust manifold, the VGT responsive to a VGT control signal to control the geometry thereof; and
a control computer configured to determine torque demand, and at least one of pressure across the compressor and a pressure gradient ratio (ΔP/P) between the exhaust manifold and the intake manifold, the control computer determining that a first condition is met in response to the torque demand decreasing at a rate greater than a first threshold, and that at least one of a second condition is met in response to the pressure across the compressor being greater than a second threshold, and a third condition is met in response to the pressure gradient ratio (ΔP/P) between the exhaust manifold and the intake manifold being greater than a third threshold; the control computer being configured to:
1. close the EGR valve in response to the first condition being met, and at least one of the second condition and the third condition being met,
2. lessen a restriction provided by the VGT responsive to the first condition being met, and at least one of the second condition and the third condition being met;
3. cause default operation of the EGR valve in response to the first condition no longer being met or the at least one of the second condition and the third condition no longer being met and
4. cause default operation of the VGT in response to the first condition no longer being met or the at least one of the second condition and the third condition no longer being met.

2. The system of claim 1 , wherein ΔP/P is defined as the difference between an exhaust manifold pressure input and an intake manifold pressure input relative to the intake manifold pressure input.

3. The system of claim 1 , wherein the control computer further determines if the first condition is met, determines if the second condition is met, and determines if the third condition is met.

4. The system of claim 1 , wherein the first, second, and third conditions are indicative of expected compressor surge responsive to the determined torque demand, pressure across the compressor, and pressure gradient ratio (ΔP/P).

5. The system of claim 1 , further including a compressor inlet pressure sensor producing a compressor inlet pressure signal indicative of turbocharger compressor inlet pressure and a compressor outlet pressure sensor producing a compressor outlet pressure signal (directly or indirectly) indicative of turbocharger compressor outlet pressure, and wherein the computer determines the pressure across the compressor as a function of signals received from the compressor inlet pressure sensor and compressor outlet pressure sensor.

6. The system of claim 1 , wherein a value of an amount of fuel to be supplied to the engine is calculated from the determined torque demand.

7. The system of claim 1 , further including an intake charge valve fluidly disposed between the compressor and the intake manifold, wherein the intake charge valve is responsive to an intake charge valve signal, and the control computer is operable to issue an intake charge valve “full open” signal when closing the EGR valve in response to the first condition being met, and at least one of the second condition, and the third condition being met.

8. The system of claim 1 , wherein the third threshold is a threshold pressure gradient ratio (ΔP/P TH ), and a high value for the pressure gradient ratio (ΔP/P) relative to the third threshold is indicative of high resistance engine pumping.

9. A method of operating a turbocharger compressor including:
determining torque demand, and at least one of pressure across the compressor, and pressure gradient ratio (ΔP/P) between an exhaust manifold and an intake manifold of an engine coupled to the compressor;
determining that a first condition is met in response to the torque demand decreasing by an amount greater than a first threshold;
determining that at least one of a second condition is met in response to the pressure across the compressor being greater than a second threshold and a third condition is met in response to the pressure gradient ratio (ΔP/P) between an exhaust manifold and an intake manifold of an engine coupled to the compressor being greater than a third threshold, and
closing an EGR valve of the engine in response to the first condition being met, and at least one of the second condition and the third condition being met;
lessening a restriction provided by a variable restrictor turbine that is in-line with an exhaust manifold in response to the first condition being met; and at least one of the second condition and the third condition being met;
causing default operation of the EGR valve in response to the first condition no longer being met or the at least one of the second condition and the third condition no longer being met and
causing default operation of the VGT in response to the first condition no longer being met or the at least one of the second condition and the third condition no longer being met.

10. The method of claim 9 , wherein ΔP/P is defined as the difference between an exhaust manifold pressure input and an intake manifold pressure input relative to the intake manifold pressure input.

11. The method of claim 9 , wherein the restriction of the variable restrictor turbine is performed according to a process that balances the reduction of intake manifold pressure with the energy supplied to the compressor.

12. The method of claim 9 , further including:
determining that the first condition is met,
determining that the second condition is met, and
determining that the third condition is met,
wherein closing the EGR valve of the engine is performed in response to determining that the first, the second, and the third conditions are satisfied.

13. The method of claim 9 , further including fully opening an intake charge valve fluidly disposed between the compressor and the intake manifold in response to the first condition being met, and at least one of the second condition and the third condition being met.

14. A non-transitory computer-readable media having instructions thereon for controlling operation of an engine, the instructions, when interpreted by a processor, cause the processor to:
determine torque demand, and at least one of pressure across the compressor, and pressure gradient ratio (ΔP/P), wherein ΔP/P includes the difference between an exhaust manifold pressure input and an intake manifold pressure input relative to one of the intake manifold pressure input;
determine that a first condition is met in response to the torque demand decreasing by an amount greater than a first threshold, and that at least one of a second condition is met in response to the pressure across the compressor being greater than a second threshold and a third condition is met in response to the pressure gradient ratio (ΔP/P) between an exhaust manifold and an intake manifold of an engine coupled to the compressor being greater than a third threshold; and
emit at least one signal configured to:
1) close an EGR valve of the engine in response to the first condition

Assignees

• Cummins Inc

Inventors

• Arslanturk Emrah
• Kurugol Orcun
• Amu Ohiorenuan J

Classifications

• F02D41/0052

  Feedback control of engine parameters, e.g. for control of air/fuel ratio or intake air amount · CPC title

• F02B37/24

  by using pumps or turbines with adjustable guide vanes · CPC title

• F02M26/47

  the characteristics being temperatures, pressures or flow rates · CPC title

• F02M26/05

  High pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust system upstream of the turbine and reintroduced into the intake system downstream of the compressor · CPC title

• F02D2200/0402

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