Method to determine reference airflow actuator positions for a gasoline engine

Patent metadata

Field	Value
Publication number	US-10273900-B2
Application number	US-201715421547-A
Country	US
Kind code	B2
Filing date	Feb 1, 2017
Priority date	Feb 1, 2017
Publication date	Apr 30, 2019
Grant date	Apr 30, 2019

Abstract

A method to determine reference actuator positions for a gasoline engine, includes entering a base torque request, a known spark advance, a known CAM position and a known exhaust gas recirculation (EGR) valve position into an inverse torque model to generate a first iteration desired air per cylinder (APC) value. The first iteration desired APC value is passed through a deadband filter to produce a filtered first iteration desired APC signal. A Predicted As Cal (PAC) spark advance is calculated for the filtered first iteration desired APC value. The PAC spark advance and the base torque request are modified, and data from a first lookup table is entered to generate a second iteration desired APC value.

First claim

What is claimed is:

1. A method to determine reference actuator positions for a gasoline engine, including:
identifying a base torque request as a last time loop execution of each of a CAM position, an exhaust gas recirculation (EGR) valve position and a predicted spark;
applying an inverse torque model to the base torque request to generate a first iteration desired air per cylinder (APC) value;
passing the first iteration APC value through a dead band filter to minimize oscillations, thereby defining a filtered APC value;
entering multiple look-up tables with the filtered APC value, including:
looking up a desired CAM position in a CAM position look-up table; and
looking up a desired EGR valve position in an EGR valve position look-up table;

calculating a Predicted As Cal (PAC) spark advance for the desired CAM position and the desired EGR valve position;
generating a second iteration desired APC value by passing the PAC spark advance through a torque model translation; and
entering an output of the torque model translation again into the CAM position look-up table and the EGR valve position look-up table.

2. The method to determine reference actuator positions for a gasoline engine of claim 1 , further including determining a reference CAM position from the CAM position look-up table.

3. The method to determine reference actuator positions for a gasoline engine of claim 2 , further including determining a reference EGR valve position from the EGR valve position look-up table.

4. The method to determine reference actuator positions for a gasoline engine of claim 3 , further including directly commanding at least one actuator using the reference CAM position and the reference EGR valve position.

5. The method to determine reference actuator positions for a gasoline engine of claim 1 , further including entering the output of the torque model translation into a wastegate lookup table to generate a reference wastegate position.

6. The method to determine reference actuator positions for a gasoline engine of claim 1 , further including entering the output of the torque model translation into a throttle lookup table to generate a reference throttle position.

7. The method to determine reference actuator positions for a gasoline engine of claim 1 , further including adding an air conditioner load during the identifying the base torque request step.

8. The method to determine reference actuator positions for a gasoline engine of claim 7 , further including adding a generator load during the identifying the base torque request step.

9. The method to determine reference actuator positions for a gasoline engine of claim 1 , further including applying constraints to the desired CAM position to obtain a constrained desired CAM position and applying constraints to the desired EGR valve position to obtain a constrained desired EGR valve position.

10. The method to determine reference actuator positions for a gasoline engine of claim 1 , further including performing the calculating step using the constrained desired CAM position and the constrained desired EGR valve position.

11. A method to determine reference actuator positions for a gasoline engine, including:
identifying a base torque request as a last time loop execution of each of a CAM position, an exhaust gas recirculation (EGR) valve position and a predicted spark;
applying an inverse torque model to the base torque request to generate a first iteration desired air per cylinder (APC) value to approximate a desired APC value;
passing the first iteration APC value defining the desired APC value through a dead band filter to minimize oscillations thereby defining a filtered APC value;
entering multiple look-up tables with the filtered APC value, including:
looking up a desired CAM position in a CAM position look-up table; and
looking up a desired EGR valve position in an EGR valve position look-up table;

applying constraints to the desired CAM position to obtain a constrained desired CAM position and to the desired EGR valve position to obtain a constrained desired EGR valve position;
calculating a Predicted As Cal (PAC) spark advance for the constrained desired CAM position and the constrained desired EGR valve position;
generating a second iteration desired APC value by passing the PAC spark advance through a torque model translation; and
entering an output of the torque model translation into the CAM position look-up table and the EGR valve position look-up table.

12. The method for determining reference actuator positions for a gasoline engine of claim 11 , further including determining a reference CAM position from the CAM position look-up table and directly commanding at least one actuator using the reference CAM position.

13. The method for determining reference actuator positions for a gasoline engine of claim 12 , further including determining a reference EGR valve position from the EGR valve position look-up table and directly commanding at least one actuator using the reference EGR valve position.

14. The method for determining reference actuator positions for a gasoline engine of claim 11 , further including determining a spark efficiency to assume for a translation from a torque APC to a desired APC.

15. The method for determining reference actuator positions for a gasoline engine of claim 14 , further including applying the calculated Predicted As Cal (PAC) spark advance to determine a spark advance at an end of a spark event.

16. The method for determining reference actuator positions for a gasoline engine of claim 15 , further including entering lookup tables to determine each of:
a final reference intake cam position signal;
a final reference exhaust cam position signal; and
a final reference EGR position signal.

17. The method for determining reference actuator positions for a gasoline engine of claim 16 , further including modifying the desired APC second iteration signal with data from at least one wastegate lookup table to create a reference wastegate position as a function of the desired APC value.

18. The method for determining reference actuator positions for a gasoline engine of claim 17 , further including modifying the desired APC second iteration signal with data from at least one throttle lookup table to create a reference throttle position.

Assignees

• Gm Global Tech Operations Llc

Inventors

• Whitney Christopher E
• Hayden David N
• Cygan Jr Gary Robert
• Levijoki Stephen P

Classifications

• F02D41/2422

  Selective use of one or more tables · CPC title

• F02D2041/1433

  using a model or simulation of the system · CPC title

• F02D41/2464 Primary

  Characteristics of actuators · CPC title

• F02D41/0077

  Control of the EGR valve or actuator, e.g. duty cycle, closed loop control of position (EGR valve position sensor F02M26/48) · CPC title

• F02P5/1516 Primary

  with means relating to exhaust gas recirculation, e.g. turbo · CPC title