Method for operating an internal combustion engine

Patent metadata

Field	Value
Publication number	US-10174692-B2
Application number	US-201414915970-A
Country	US
Kind code	B2
Filing date	Sep 2, 2014
Priority date	Sep 4, 2013
Publication date	Jan 8, 2019
Grant date	Jan 8, 2019

Abstract

Method for the operation of an internal combustion engine having a plurality of cylinders ( 11 to detect misfires. An exhaust gas sensor at the exhaust gas of every cylinder of the internal combustion engine measures at least one actual exhaust gas value individually for the respective cylinder, and the respective measured actual exhaust gas value is compared with a reference exhaust gas value to determine at least one cylinder-specific deviation between the reference exhaust gas value and the actual exhaust gas value for each of the cylinders. It is determined for every cylinder based on the cylinder-specific deviation or based on every cylinder-specific deviation whether or not misfires are occurring at the respective cylinder.

First claim

The invention claimed is:

1. A method for cylinder-specific detection of misfires in an internal combustion engine having a plurality of cylinders and at least one exhaust gas sensor at an exhaust gas outlet of one or more of the plurality of cylinders, comprising:
calibrating the at least one exhaust gas sensor, the at least one exhaust gas sensor configured as one of an NO x sensor, a CH 4 sensor, an H 2 sensor, or a soot sensor;
measuring at least one actual exhaust gas value for each of the plurality of cylinders;
comparing each respective measured actual exhaust gas value with a reference exhaust gas value to determine at least one cylinder-specific deviation between the reference exhaust gas value and the at least one actual exhaust gas value for each of the cylinders, wherein the reference exhaust gas value is based at least in part on a full load operation and a partial load operation operating point of the internal combustion engine;
determining for each of the plurality of cylinders whether or not a misfire is occurring at a respective cylinder based at least in part on one of:
the cylinder-specific deviation and
every cylinder-specific deviation; and

at least one of:
interrupting a fuel supply to a respective misfire cylinder when a misfire occurs, and
influencing an ignition time at a respective misfire cylinder when a misfire occurs, and
influencing a fuel/air ratio at a respective misfire cylinder when a misfire occurs.

2. The method according to claim 1 , wherein at least one of the at least one actual exhaust gas value and every actual exhaust gas value is measured by a respective at least one exhaust gas sensor at the exhaust gas outlet of each of the plurality of cylinders.

3. The method according to claim 2 , wherein each respective actual exhaust gas value is acquired at a respective exhaust gas sensor of a respective cylinder exclusively in a cylinder-specific crankshaft angle range to minimize an interaction with exhaust gas expelled from other cylinders during a cylinder-specific acquisition of the at least one actual exhaust gas value.

4. The method according to claim 1 , wherein at least one of the at least one actual exhaust gas value and every actual exhaust gas value is measured by a shared exhaust gas sensor for a plurality of cylinders.

5. The method according to claim 4 , wherein the exhaust gas of exclusively one cylinder of the plurality of cylinders is supplied to the shared exhaust gas sensor to minimize an interaction with exhaust gas expelled from other of the plurality of cylinders during a cylinder-specific acquisition of the at least one actual exhaust gas value.

6. The method according to claim 1 , wherein for every cylinder at least one of:
an actual NO x value is acquired as the at least one actual exhaust gas value for every cylinder by the exhaust gas sensor configured as an NO x sensor,
a fuel-air ratio is acquired as the at least one actual exhaust gas value for every cylinder by the exhaust gas sensor configured as a lambda sensor,
residual oxygen content is acquired as the at least one actual exhaust gas value for every cylinder by the exhaust gas sensor configured as the lambda sensor, and
and one or more of an actual CH 4 value, an actual particle value, an actual soot value, and an actual H 2 value is acquired as the at least one actual exhaust gas value.

7. The method according to claim 6 , wherein a current measurement value of an actual combustion value is used as the at least one actual exhaust gas value.

8. The method according to claim 1 , wherein one of an average value, a maximum value, a time integral, and an inflection point from measurements acquired over a measurement interval is used as the at least one actual exhaust gas value.

9. The method according to claim 1 , wherein the reference exhaust gas value of a respective cylinder is based at least in part on the at least one actual exhaust gas value of at least one other cylinder.

10. The method according to claim 1 , wherein the calibrating further comprises:
calibrating a respective exhaust gas sensor by:
applying a reference gas to the respective exhaust gas sensor to remove exhaust gas from the respective exhaust gas sensor,
acquiring a measurement value acquired when the reference gas is applied to the respective exhaust gas sensor,
calibrating the respective exhaust gas sensor based at least in part on the measurement,
wherein after the calibration, exhaust gas is again applied to the respective exhaust gas sensor.

11. The method according to claim 1 , wherein in a turbocharged engine a fluidic connection is produced downstream of a respective outlet of a cylinder but upstream of a confluence of a plurality of exhaust gases of other cylinders and downstream of at least one exhaust turbine, and the at least one respective sensor is arranged for determining the at least one actual exhaust gas value in this fluidic connection.

12. A method for cylinder-specific detection of misfires in an internal combustion engine having a plurality of cylinders and at least one exhaust gas sensor at an exhaust gas outlet of one or more of the plurality of cylinders, comprising:
controlling a respective valve for each of the plurality of cylinders so that the exhaust gas of exclusively one cylinder is supplied to a shared exhaust gas sensor, the shared exhaust gas sensor configured as one of an NO x sensor, a CH 4 sensor, an H 2 sensor, or a soot sensor;
measuring at least one actual exhaust gas value for each of the plurality of cylinders;
comparing each respective measured actual exhaust gas value with a reference exhaust gas value to determine at least one cylinder-specific deviation between the reference exhaust gas value and the at least one actual exhaust gas value for each of the cylinders, wherein the reference exhaust gas value is based at least in part on a full load operation and a partial load operation operating point of the internal combustion engine; and
determining for each of the plurality of cylinders whether or not a misfire is occurring at a respective cylinder based at least in part on one of:
the cylinder-specific deviation and
every cylinder-specific deviation; and

at least one of:
interrupting a fuel supply to a respective misfire cylinder when a misfire occurs, and
influencing an ignition time at a respective misfire cylinder when a misfire occurs, and
influencing a fuel/air ratio at a respective misfire cylinder when a misfire occurs.

Assignees

• Man Diesel & Turbo Se
• Man Energy Solutions Se

Inventors

• Döring Andreas
• Auer Matthias

Classifications

• F02D41/1454

  the characteristics being an oxygen content or concentration or the air-fuel ratio · CPC title

• F02D41/008 Primary

  Controlling each cylinder individually · CPC title

• F02D41/1438

  using means for determining characteristics of the combustion gases; Sensors therefor · CPC title

• F02D41/146

  the characteristics being an NOx content or concentration · CPC title

• F02D41/1466

  the characteristics being a soot concentration or content · CPC title