METHOD AND SYSTEM FOR ACTIVE CASING TREATMENT CONTROL

• US 20190024574A1
• Filed: 07/18/2017
• Published: 01/24/2019
• Est. Priority Date: 07/18/2017
• Status: Active Grant

• Current Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Original Assignee: Ford Global Technologies, LLC (Ford Motor Company)
• Inventors: Upadhyay, Devesh, Van Nieuwstadt, Michiel J., Hanna, David R., Hu, Leon
• Granted Patent: US 10,508,591 B2
• Time in Patent Office: Days
• CPC Class Codes: F02B 2037/125 Control for avoiding pump stall or surge
• CPC Class Codes: F02B 37/004 with exhaust drives arranged in series
• CPC Class Codes: F02B 37/162 by bypassing, e.g. partially, intake air from pump inlet to pump outlet
• CPC Class Codes: F02B 37/18 by bypassing exhaust from the inlet to the outlet of turbine or to the atmosphere
• CPC Class Codes: F02B 37/24 by using pumps or turbines with adjustable guide vanes
• CPC Class Codes: F02D 2041/1412 using a predictive controller
• CPC Class Codes: F02D 23/02 the engines being of fuel-injection type
• CPC Class Codes: F02D 41/0007 for control of turbo-charged or super-charged engines control of the pumps per se F02B37/12
• CPC Class Codes: F02D 41/0052 Feedback control of engine parameters, e.g. for control of air/fuel ratio or intake air amount
• CPC Class Codes: F02M 26/06 Low pressure loops, i.e. wherein recirculated exhaust gas is taken out from the exhaust downstream of the turbocharger turbine and reintroduced into the intake system upstream of the compressor
• CPC Class Codes: F04D 29/4213 suction ports
• CPC Class Codes: F04D 29/685 Inducing localised fluid recirculation in the stator-rotor interface
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies
• CPC Class Codes: Y02T 10/40 Engine management systems

Abstract

Methods and systems are provided for adjusting an active casing treatment of a compressor responsive to a predicted engine condition. In one example, a controller may actuate a sleeve of a variable geometry compressor casing to a position selected based on each of a compressor pressure ratio and a mass flow through the compressor, as well as driver behavior and predicted road conditions; and adjust each of an EGR actuator and a boost actuator based on the selected position to maintain the compressor pressure ratio during the actuating.

Claims

1. A method for a boosted engine, comprising:

actuating a sleeve of a variable geometry compressor casing to a position selected based on each of a compressor pressure ratio and a mass flow through the compressor; and

adjusting each of an EGR actuator and a boost actuator based on the selected position to maintain the compressor pressure ratio during the actuating.

2. The method of claim 1, wherein the actuating includes:

predicting a change in each of a compressor surge margin relative to a surge limit and a compressor choke margin relative to a choke limit based on the compressor pressure ratio and mass flow;

responsive to the predicted decrease in compressor surge margin, actuating the sleeve to a first position; and

responsive to a predicted decrease in the compressor choke margin, actuating the sleeve to a second position.

3. The method of claim 2, wherein when the sleeve is in the first position, a surge slot of the compressor is open while a choke slot of the compressor is closed and compressed air is recirculated from compressor impeller blades to a compressor inlet via the surge slot, and wherein when the sleeve is in the second position, the surge slot is closed while the choke slot is open, and compressed air is recirculated from the compressor inlet to the compressor impeller blades via the choke slot.

4. The method of claim 2, wherein the sleeve is actuated to the first position prior to the compressor pressure ratio reaching the surge limit, and wherein the sleeve is actuated to the second position prior to the compressor pressure ratio reaching the choke limit.

5. The method of claim 2, wherein the predicting the change in compressor surge margin or compressor choke margin is based on driver behavior including estimated energy density of driver pedal demand.

6. The method of claim 5, wherein the predicting is further based on input from a navigational system, the input including altitude and road gradient.

7. The method of claim 5, wherein the position is further selected based on a prior frequency of sleeve actuation relative to a threshold, the threshold determined as a function of the estimated energy density of driver pedal demand, the threshold lowered as the estimated energy density increases, wherein the sleeve is maintained in a current position responsive to the prior frequency of sleeve actuation being higher than the threshold even as the compressor surge margin or compressor choke margin decreases.

8. The method of claim 3, further comprising, responsive to no predicted decrease in the compressor surge margin or the compressor choke margin, maintaining the sleeve in a default position, wherein both the surge slot and the choke slot are closed.

9. The method of claim 3, wherein the compressor is driven by an exhaust turbine, wherein the EGR actuator includes an EGR valve coupled in an EGR passage recirculating exhaust from an exhaust passage, downstream of the turbine to upstream of the compressor, and wherein the boost actuator includes one of a variable geometry turbine and a waste-gate valve, the waste-gate valve coupled in a waste-gate bypassing the exhaust turbine.

10. The method of claim 9, wherein the adjusting includes:

responsive to the sleeve being actuated to the first position, increasing an opening of the EGR valve and increasing an opening of the waste-gate valve, the increasing based on a predicted drop in boost pressure due to the actuating of the sleeve to the first position; and

responsive to the sleeve being actuated to the second position, decreasing the opening of the EGR valve and decreasing the opening of the waste-gate valve, the decreasing based on a predicted rise in boost pressure due to the actuating of the sleeve to the second position.

11. The method of claim 9, wherein the adjusting includes:

responsive to the sleeve being actuated to the first position, increasing a nozzle opening of the variable geometry turbine, the increasing based on a predicted change in boost pressure due to the actuating of the sleeve to the first position; and

responsive to the sleeve being actuated to the second position, decreasing the nozzle opening of the variable geometry turbine, the decreasing based on the predicted change in boost pressure due to the actuating of the sleeve to the second position.

12. A method, comprising:

dynamically adjusting each of a choke margin to a choke limit and a surge margin to a surge limit of a compressor based on driver behavior including energy density of driver pedal demand;

actuating a sleeve of an active casing of the compressor to a choke slot responsive to compressor operation in the choke margin; and

actuating the sleeve to a surge slot responsive to compressor operation in the surge margin.

13. The method of claim 12, wherein the actuating is responsive to a change in driver pedal demand, the method further comprising, estimating the energy density of the driver pedal demand based on each of a rate, a magnitude, and a frequency of driver pedal application over a drive cycle.

14. The method of claim 12, further comprising, adjusting each of an EGR actuator and a boost actuator based on the actuating to operate the compressor out of the choke margin or surge margin.

15. The method of claim 14, wherein the EGR actuator includes one or more of a high pressure EGR valve recirculating exhaust gas from upstream of an exhaust turbine to downstream of the compressor, and a low pressure EGR valve recirculating exhaust gas from downstream of the exhaust turbine to upstream of the compressor, and wherein the boost actuator includes one of a waste-gate valve for flowing exhaust gas to a tailpipe while bypassing the turbine, and a variable geometry turbine actuator for adjusting a nozzle opening of the turbine.

16. The method of claim 15, wherein the adjusting includes:

responsive to the sleeve being actuated to the choke slot, decreasing an opening of the low pressure EGR valve, increasing an opening of the high pressure EGR valve, decreasing an opening of the waste-gate valve, and decreasing the nozzle opening; and

responsive to the sleeve being actuated to the surge slot, increasing the opening of the low pressure EGR valve, decreasing the opening of the high pressure EGR valve, increasing the opening of the waste-gate valve, and increasing nozzle opening.

17. The method of claim 12, wherein each of the choke margin and the surge margin is further adjusted, dynamically, based on a measured frequency of sleeve actuation of the drive cycle, the surge margin increased and the choke margin increased as the measured frequency exceeds a threshold frequency.

18. A boosted engine system, comprising:

an engine;

an intake compressor having an impeller, a choke slot, a surge slot, an actuatable annular casing housing the impeller, the casing comprising a sleeve slot, and an actuator coupled to a sleeve of the casing;

an exhaust turbine;

an EGR valve coupled in an EGR passage for recirculating exhaust gas from downstream of the turbine to upstream of the compressor;

a pedal for receiving operator torque demand; and

a controller with computer readable instructions stored on non-transitory memory for;

responsive to a current change in pedal position,

comparing compressor efficiency with the actuator at a current position relative to each of a first and second position,

estimating compressor efficiency with the actuator at a first and a second position, the compressor efficiency estimated based on compressor pressure ratio, mass flow, the current change in pedal position, and a history of past changes in pedal position over a given drive cycle;

actuating, via the actuator, the sleeve to one of the first and second position having greater compressor efficiency;

estimating a boost pressure disturbance associated with the actuating; and

adjusting the opening of the EGR valve based on the estimated boost pressure disturbance.

19. The system of claim 18, wherein the controller includes further instructions for:

adjusting an exhaust flow bypassing the waste-gated turbine based on the estimated boost pressure disturbance when the turbine is a waste-gated turbine; and

adjusting a blade angle of the turbine based on the estimated boost pressure disturbance when the turbine is a variable geometry turbine.

20. The system of claim 18, wherein in the first position, the sleeve slot is aligned with the choke slot, and compressed air is drawn into the impeller from a compressor inlet via the choke slot, and wherein in the second position, the sleeve slot is aligned with the surge slot, and compressed air is recirculated from the impeller to the compressor inlet via the surge slot.