Detection of reversion based on mass air flow sensor readings

Patent metadata

Field	Value
Publication number	US-2016237940-A1
Application number	US-201514623817-A
Country	US
Kind code	A1
Filing date	Feb 17, 2015
Priority date	Feb 17, 2015
Publication date	Aug 18, 2016
Grant date	—

Abstract

An engine system includes a mass air flow sensor and a manifold absolute pressure sensor configured to provide a real-time MAP signal during an event. The mass air flow sensor is configured to generate a set of mass air flow readings based on an airflow through the mass air flow sensor during the event. The set of mass air flow readings have a maximum value and a minimum value. A controller is configured to execute a method for detecting reversion in the air flow. If the rate of change in the real-time MAP signal is less than the predetermined transient threshold value (T 0 ), the method includes setting a delta factor (D) as the difference between the maximum value and the minimum value. Reversion is detected based at least partially on a magnitude of the delta factor (D).

First claim

1 . An engine system comprising:
a manifold absolute pressure sensor configured to provide a real-time MAP signal during an event; a mass air flow sensor configured to generate a set of mass air flow readings based on an airflow through the mass air flow sensor during the event, the set of mass air flow readings having a maximum value and a minimum value; and a controller operatively connected to the mass air flow sensor and the manifold absolute pressure sensor and having a processor and tangible, non-transitory memory on which is recorded instructions for executing a method for detecting reversion in the airflow; wherein execution of the instructions by the processor causes the controller to:
determine whether a rate of change in the real-time MAP signal is greater than or equal to a predetermined transient threshold value (T 0 );
if the change in the real-time MAP signal is less than the predetermined transient threshold value (T 0 ), set a delta factor (D) as the difference between the maximum value and the minimum value of the set of mass air flow readings; and
detect the reversion based at least partially on a magnitude of the delta factor (D).

2 . The system of claim 1 , wherein the controller is configured to set up a reversion zone flag (R) such that presence of the reversion is indicated by the reversion zone flag being one (R=1) and absence of the reversion is indicated by the reversion zone flag being zero (R=0).

3 . The system of claim 2 , wherein:
if the delta factor (D) is greater than or equal to the entry threshold value for less than a first number of consecutive events, the controller is configured to make no change to the reversion zone flag; and if the delta factor (D) is greater than or equal to the entry threshold value for at least the first number of consecutive events, the controller is configured to set the reversion zone flag to one (R=1).

4 . The system of claim 3 , wherein the first number of consecutive events is three.

5 . The system of claim 2 , wherein:
if the delta factor (D) is less than or equal to the exit threshold value for less than a second number of consecutive events, the controller is configured to make no change to the reversion zone flag; and if the delta factor (D) is less than or equal to the exit threshold value for at least the second number of consecutive events, the controller is configured to set the reversion zone flag to zero (R=0).

6 . The system of claim 5 , wherein the second number of consecutive events is four.

7 . The system of claim 2 , wherein the vehicle includes a throttle valve and wherein:
if the rate of change of the real-time MAP signal is greater than or equal to the predetermined transient threshold value (T 0 ), the controller is configured to determine if a predefined open throttle condition is met; and if the predefined open throttle condition is met, the controller is configured to set the reversion zone flag to zero (R=0).

8 . The system of claim 7 , wherein the predefined open throttle condition is defined by the throttle valve being greater than 90% open.

9 . The system of claim 7 , wherein the predefined open throttle condition is defined by a pressure downstream of the throttle valve being 90% greater than a pressure upstream of the throttle valve.

10 . The system of claim 7 , wherein:
if the predefined open throttle condition is met, the controller is configured to set the delta factor (D) as the difference between the maximum value and the minimum value of the set of mass air flow readings; if the delta factor (D) is greater than an entry threshold value for less than a first number of consecutive events, the controller is configured to make no change to the reversion zone flag; and if the delta factor (D) is greater than the entry threshold value for at least the first number of consecutive events, the controller is configured to set the reversion zone flag to one (R=1).

11 . The system of claim 7 , wherein:
if the delta factor (D) is less than or equal to the entry threshold value for less than a second number of consecutive events, the controller is configured to make no change to the reversion zone flag; and if the delta factor (D) is less than or equal to the exit threshold value for at least the second number of consecutive events, the controller is configured to set the reversion zone flag to zero (R=0).

12 . A method of detecting reversion in an engine system having a manifold absolute pressure sensor configured to provide a real-time MAP signal during an event and a mass air flow sensor, the method comprising:
determining whether a rate of change in the real-time MAP signal is greater than or equal to a predetermined transient threshold value (T 0 ); wherein the mass air flow sensor is configured to generate a set of mass air flow readings based on an airflow through the mass air flow sensor during the event, the set of mass air flow readings having a maximum value and a minimum value; if the rate of change in the real-time MAP signal is less than the predetermined transient threshold value (T 0 ), setting a delta factor (D) as the difference between the maximum value and the minimum value; and detecting the reversion based at least partially on a magnitude of the delta factor (D).

13 . The method of claim 12 , further comprising:
setting up a reversion zone flag (R) such that presence of the reversion is indicated by the reversion zone flag being one (R=1) and absence of the reversion is indicated by the reversion zone flag being zero (R=0), wherein the reversion zone flag is initialized to zero.

14 . The method of claim 13 , further comprising:
determining if the delta factor (D) is greater than or equal to an entry threshold value for at least a first number of consecutive events; if the delta factor (D) is greater than or equal to the entry threshold value for less than the first number of consecutive events, making no change to the reversion zone flag; and if the delta factor (D) is greater than or equal to the entry threshold value for at least the first number of consecutive events, setting the reversion zone flag to one (R=1).

15 . The method of claim 13 , further comprising:
determining if the delta factor (D) is less than or equal to an exit threshold value for at least a second number of consecutive events; if the delta factor (D) is less than or equal to the exit threshold value for less than the second number of consecutive events, making no change to the reversion zone flag; and if the delta factor (D) is less than or equal to the exit threshold value for at least the second number of consecutive events, setting the reversion zone flag to zero (R=0).

16 . The method of claim 13 , wherein the engine system includes a throttle valve and further comprising:
if the rate of change of the real-time MAP signal is greater than or equal to the predetermined transient threshold value (T 0 ), determining if a predefined open throttle condition is met; wherein the predefined open throttle condition is defined by a minimum opening of the throttle valve; if the predefined open throttle condition is not met, setting the reversion zone flag to zero (R=0); and if the predefined open throttle condition is met, determining the maximum value and the minimum value of the set of mass air flow readings for each respective intake event and setting the delta factor (D) as the difference between the maximum value and the minimum value.

17 . The method of claim 16 , wherein the predefined open throttle condition is met when the thrott

Assignees

• Gm Global Tech Operations Llc

Inventors

• Hu Yiran
• Li Shifang
• Chang Chen-Fang

Classifications

• F02D41/263 Primary

  the program execution being modifiable by physical parameters · CPC title

• F02M35/1038

  for temperature or pressure · CPC title

• F02M35/10386

  for flow rate (air flow meters in air cleaners F02M35/021; circuit arrangements for generating control signals by measuring intake air flow F02D41/18) · CPC title

• F02D2200/0406

  Intake manifold pressure · CPC title

• F02D2041/286

  comprising means for signal processing · CPC title