Differential pressure valve based boost device inlet pressure optimization

Patent metadata

Field	Value
Publication number	US-11092093-B2
Application number	US-201916681354-A
Country	US
Kind code	B2
Filing date	Nov 12, 2019
Priority date	Nov 16, 2018
Publication date	Aug 17, 2021
Grant date	Aug 17, 2021

Abstract

Techniques for controlling a forced-induction engine having a low pressure cooled exhaust gas recirculation (LPCEGR) system comprise determining a target boost device inlet pressure for each of one or more systems that could require a boost device inlet pressure change as part of their operation and boost device inlet pressure hardware limits for a set of components in the induction system, determining a final target boost device inlet pressure based on the determined sets of target boost device inlet pressures and boost device inlet pressure hardware limits, and controlling a differential pressure (dP) valve based on the final target boost device inlet pressure to balance (i) competing boost device inlet pressure targets of the one or more systems and (ii) the set of boost device inlet pressure hardware limits in order to optimize engine performance and prevent component damage.

First claim

What is claimed is:

1. A control system for a forced-induction engine comprising a low pressure cooled exhaust gas recirculation (LPCEGR) system, the control system comprising:
a differential pressure (dP) valve (i) disposed in an induction system of the engine at a point upstream from an inlet of a boost device of the engine and a recirculation point of the LPCEGR system and (ii) configured to control a boost device inlet pressure in the induction system; and
a controller configured to:
determine a set of target boost device inlet pressures including a target boost device inlet pressure for each of one or more systems that could require a boost device inlet pressure change as part of their operation;
determine a set of boost device inlet pressure hardware limits for a set of components in the induction system;
determine a final target boost device inlet pressure based on the determined set of target boost device inlet pressures and the determined set of boost device inlet pressure hardware limits by (i) determining a minimum of the set of target boost device inlet pressures to obtain an intermediate target boost device inlet pressure and (ii) determining a maximum of the intermediate target boost device inlet pressure and the set of boost device inlet pressure hardware limits to obtain the final target boost device inlet pressure; and
control the dP valve based on the final target boost device inlet pressure, wherein controlling the dP valve based on the final target boost device inlet pressure balances (i) competing boost device inlet pressure targets of the one or more systems and (ii) the set of boost device inlet pressure hardware limits in order to optimize engine performance and prevent component damage.

2. The control system of claim 1 , wherein:
the one or more systems comprise the LPCEGR system, an evaporative emissions (EVAP) system, a crankcase ventilation system, and an on-board diagnostic (OBD) system; and
the set of target boost device inlet pressures comprises target boost device inlet pressures for each of a target NVH for the engine, a target flow through the LPCEGR system, a target EVAP purge vapor flow, a target positive crankcase ventilation (PCV) blow-by vapor flow, and a target OBD test pressure.

3. The control system of claim 1 , wherein the boost device is a turbocharger and the set of hardware limits comprises a surge limit of a pressure ratio of a compressor of the turbocharger, a pressure limit of the dP valve, and an oil pullover pressure limit of the compressor.

4. The control system of claim 1 , wherein the controller is configured to control the dP valve based on the final target boost device inlet pressure using a primary opcn loop open-loop control scheme with a secondary closed-loop control scheme.

5. The control system of claim 4 , wherein the primary open-loop control scheme comprises:
determining a target dP valve boost device inlet pressure based on the final target boost device inlet pressure and an air box outlet pressure;
saturating the target dP valve boost device inlet pressure at zero; and
determining, using a calibrated two-dimensional table, an open-loop target dP valve position based on the saturated target dP valve boost device inlet pressure and a current dP valve mass flow.

6. The control system of claim 5 , wherein the secondary closed-loop control scheme comprises:
determining a dP valve position feedback error based on the final target boost device inlet pressure and a measured boost device inlet pressure; and
determining a closed-loop target dP valve position based on the dP valve position feedback error using a proportional-integral (PI) control scheme.

7. The control system of claim 6 , wherein the controller is further configured to:
sum the open-loop and closed-loop target dP valve positions to obtain a final target dP valve position; and
command the dP valve to the final target dP valve position to optimize the engine performance and prevent the component damage.

8. The control system of claim 1 , wherein the engine is a twin-turbocharged, six-cylinder engine and the LPCEGR system is associated with one turbocharger loop of the engine.

9. A method of controlling a forced-induction engine having a low pressure cooled exhaust gas recirculation (LPCEGR) system, the method comprising:
determining, by a controller of the engine, a set of target boost device inlet pressures at an inlet of a boost device of the engine, the set of target boost device inlet pressures comprising a target boost device inlet pressure for each of one or more systems that could require a boost device inlet pressure change as part of their operation;
determining, by the controller, a set of boost device inlet pressure hardware limits for a set of components in an induction system of the engine;
determining, by the controller, a final target boost device inlet pressure based on the determined set of target boost device inlet pressures and the determined set of boost device inlet pressure hardware limits by (i) determining a minimum of the set of target boost device inlet pressures to obtain an intermediate target boost device inlet pressure and (ii) determining a maximum of the intermediate target boost device inlet pressure and the set of boost device inlet pressure hardware limits to obtain the final target boost device inlet pressure; and
controlling, by the controller, a differential pressure (dP) valve based on the final target boost device inlet pressure, wherein the dP valve is (i) disposed in the induction system at a point upstream from the boost device inlet and a recirculation point of the LPCEGR system and (ii) configured to control a boost device inlet pressure,
wherein controlling the dP valve based on the final target boost device inlet pressure balances (i) competing boost device inlet pressure targets of the one or more systems and (ii) the set of boost device inlet pressure hardware limits in order to optimize engine performance and prevent component damage.

10. The method of claim 9 , wherein:
the one or more systems comprise the LPCEGR system, an evaporative emissions (EVAP) system, a crankcase ventilation system, and an on-board diagnostic (OBD) system; and
the set of target boost device inlet pressures comprises target boost device inlet pressures for each of a target NVH for the engine, a target flow through the LPCEGR system, a target EVAP purge vapor flow, a target positive crankcase ventilation (PCV) blow-by vapor flow, and a target OBD test pressure.

11. The method of claim 9 , wherein the boost device is a turbocharger and the set of hardware limits comprises a surge limit of a pressure ratio of a compressor of the turbocharger, a pressure limit of the dP valve, and an oil pullover pressure limit of the compressor.

12. The method of claim 9 , wherein controlling the dP valve based on the final target boost device inlet pressure comprises using a primary open-loop control scheme with a secondary closed-loop control scheme.

13. The method of claim 12 , wherein the primary open-loop control scheme comprises:
determining a target dP valve boost device inlet pressure based on the final target boost device inlet pressure and an air box outlet pressure;
saturating the target dP valve boost device inlet pressure at zero; and
determining, using a calibrated two-dimensional table, an open-loop target dP valve position based on the saturated target dP valve boost device inlet pressure and a current dP valve mass flow.

14. The method of claim 13 , wherein the secondary closed-loop control scheme comprises:
determining a dP valve position feedback error based on the f

Assignees

• Lawrence David
• Bayer Ethan E
• Attard William P
• Wang Shu
• Fca Us Llc

Inventors

• Lawrence David
• Bayer Ethan E
• Attard William P
• Wang Shu

Classifications

• F02M26/06

  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 title

• F02B75/20

  with cylinders all in one line · CPC title

• F02D41/0007

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

• F02M26/10

  having means to increase the pressure difference between the exhaust and intake system, e.g. venturis, variable geometry turbines, check valves using pressure pulsations or throttles in the air intake or exhaust system · CPC title

• F02B47/08

  the substances including exhaust gas · CPC title