Valve fault detection

• US 9,890,732 B2
• Filed: 12/20/2016
• Issued: 02/13/2018
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Tula Technology, Incorporated (BorgWarner Incorporated)
• Original Assignee: Tula Technology, Incorporated (BorgWarner Incorporated)
• Inventors: Younkins, Matthew A., Chen, Shikui Kevin
• Primary Examiner(s): LATHERS, KEVIN ANTHONY
• Application Number:
  US15/384,924
• Publication Number:
  US 20170101956A1
• Time in Patent Office: 420 Days
• CPC Class Codes: F02B 77/082 relating to valves
• CPC Class Codes: F02D 13/06 Cutting-out cylinders
• CPC Class Codes: F02D 17/02 Cutting-out cutting-out engines in multiple engine arrangements F02D25/04
• CPC Class Codes: F02D 2041/001 for engines with variable valve actuation
• CPC Class Codes: F02D 2041/1412 using a predictive controller
• CPC Class Codes: F02D 2041/1433 using a model or simulation of the system
• CPC Class Codes: F02D 2041/227 Limping Home, i.e. taking specific engine control measures at abnormal conditions
• CPC Class Codes: F02D 35/023 by determining the cylinder pressure
• CPC Class Codes: F02D 35/024 using an estimation
• CPC Class Codes: F02D 41/0087 Selective cylinder activation, i.e. partial cylinder operation deceleration cut-off F02D41/123
• CPC Class Codes: F02D 41/1401 characterised by the control or regulation method F02D41/1473, F02D41/1477 take precedence
• CPC Class Codes: F02D 41/1448 the characteristics being an exhaust gas pressure
• CPC Class Codes: F02D 41/1498 measuring engine roughness
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02D 41/221 relating to the failure of actuators or electrically driven elements
• CPC Class Codes: F02D 41/3058 the engine working with a variable number of cycles
• CPC Class Codes: G01L 3/00 Measuring torque, work, mechanical power, or mechanical efficiency, in general
• CPC Class Codes: G01M 15/042 by monitoring a single specific parameter not covered by groups G01M15/06 - G01M15/12
• CPC Class Codes: G01P 15/00 Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
• CPC Class Codes: Y02T 10/12 Improving ICE efficiencies

Abstract

Methods and systems are described for detecting valve actuation faults in internal combustion engines operating in a skip fire operational mode. In one aspect, for each skip fire working cycle, an expected exhaust pressure is determined for a time period corresponding to a potential exhaust event. One or more exhaust gas pressure sensors are then used to measure an actual exhaust pressure during the potential exhaust period. The actual exhaust pressure is compared to the expected exhaust pressure to determine whether a valve actuation fault has occurred. A variety of valve actuation faults can be identified using the described approach. In some embodiments pressure sensors are deployed in the runners of the exhaust manifold.

Claims

1. A method of identifying valve actuation faults while operating an engine in a skip fire mode, the engine including a plurality of working chambers and an exhaust system, each working chamber having an associated exhaust valve and being arranged to operate in a succession of working cycles, each working cycle having a corresponding potential exhaust period the method comprising:

operating the engine in a skip fire mode in which working cycles are selectively skipped or fired;

for each of a multiplicity of selected working cycles estimating an expected exhaust pressure at a selected location in the exhaust system during a time period corresponding to the associated potential exhaust period;

for each of the multiplicity of selected working cycles measuring an actual exhaust pressure at the selected location in the exhaust system during the time period corresponding to the associated potential exhaust period; and

for each of the multiplicity of selected working cycles comparing the actual exhaust pressure to the expected exhaust pressure to determine whether a valve actuation fault has occurred; and

when it is determined that a valve actuation fault has occurred, performing at least one of (a) altering an aspect of control of the engine while the engine is operating in the skip fire mode in response to said determination; and

(b) recording the detection of the valve actuation fault in a diagnostics system.

2. A method as recited in claim 1 wherein during at least some of the skipped working cycles, the exhaust valve associated with the corresponding working cycle is held closed and wherein the determination of whether a valve actuation fault has occurred includes determining whether the corresponding exhaust valve failed to open during a selected fired working cycle when it was intended to open during the selected fired working cycle.

3. A method as recited in claim 1 wherein the determination of whether a valve actuation fault has occurred includes determining whether the corresponding exhaust valve opened during a selected working cycle when it was intended to be held closed during the selected working cycle.

4. A method as recited in claim 3 wherein the determination of whether a valve actuation fault has occurred includes determining whether an unexpected air pulse was pumped through the corresponding working chamber.

5. A method as recited in claim 4 further comprising:

sensing a level of oxygen in exhaust gas pulses in the exhaust system, each exhaust gas pulse corresponding to a particular one of the working cycle of a particular one of the working chambers; and

determining whether an unexpected air pulse was pumped through a particular one of the working chambers during a particular one of the working cycles based at least in part on the sensed oxygen level in the exhaust gas pulse corresponding to the particular one of the working cycles and the measured exhaust pressure associated with such exhaust gas pulse.

6. A method as recited in claim 3 wherein the determination of whether a valve actuation fault has occurred includes determining whether combusted exhaust gases were expelled from the corresponding working chamber when they were intended to be held within the working chamber to form a high pressure gas spring.

7. A method as recited in claim 3 wherein the determination of whether a valve actuation fault has occurred includes determining whether an unexpected reexhaust event has occurred in corresponding working chamber.

8. A method as recited in claim 1 wherein the determination of whether a valve actuation fault has occurred includes determining whether an exhaust valve timing fault has occurred.

9. A method as recited in claim 1 wherein the determination of whether a valve actuation fault has occurred includes determining whether an exhaust valve lift fault has occurred.

10. A method as recited in claim 1 wherein the determination of whether a valve actuation fault has occurred includes determining whether an intake valve actuation fault has occurred.

11. A method as recited in claim 1 wherein:

each exhaust valve has an associated exhaust port and the exhaust system includes an exhaust manifold having a plurality of runners, each runner being arranged to receive exhaust gasses from an associated one of the exhaust ports; and

a plurality of exhaust gas pressure sensors, each exhaust gas pressure sensor being arranged to detect exhaust gas pressure in an associated one of the runners.

12. A method as recited in claim 11 wherein each runner is associated with a single one the working chambers.

13. A method as recited in claim 1 further comprising:

sensing a level of oxygen in exhaust gas pulses in the exhaust system, each exhaust gas pulse corresponding to a particular one of the working cycle of a particular one of the working chambers; and

determining whether an unexpected air pulse was pumped through a particular one of the working chambers during a particular one of the working cycles based at least in part on the sensed oxygen level in the exhaust gas pulse corresponding to the particular one of the working cycles.

14. A valve actuation fault detection system for detecting valve actuation faults while operating an engine in a skip fire mode, the engine including a plurality of working chambers and an exhaust system, each working chamber having an associated exhaust valve and being arranged to operate in a succession of working cycles, each working cycle having a corresponding potential exhaust period the valve actuation fault detection system comprising:

at least one exhaust gas pressure sensor for measuring exhaust gas pressure;

an expected exhaust gas pressure determining module for determining an expected exhaust pressure at a selected location in the exhaust system during potential exhaust period associated with a particular working cycle; and

a fault identifier for comparing the actual exhaust pressure to the expected exhaust pressure for each of a multiplicity of selected working cycles to determine whether a valve actuation fault has occurred, wherein the fault identifier is configured to, in response to the determination of a valve actuation fault, perform at least one of (a) notify an engine control component to facilitate altering an aspect of control of the engine while the engine is operating in the skip fire mode in response to said determination, and (b) record the detection of the valve actuation fault in a diagnostics system.

15. A method of identifying valve actuation faults while operating an engine in a skip fire mode, the engine including a plurality of working chambers and an exhaust system, each working chamber having an associated exhaust valve and being arranged to operate in a succession of working cycles, each working cycle having a corresponding potential exhaust period the method comprising:

operating the engine in a skip fire mode in which working cycles are selectively skipped or fired;

sensing a level of oxygen in exhaust gas pulses in the exhaust system, each exhaust gas pulse corresponding to a particular one of the working cycles of a particular one of the working chambers; and

determining whether an unexpected air pulse was pumped through a particular one of the working chambers during a particular one of the working cycles based at least in part on the sensed oxygen level in the exhaust gas pulse corresponding to the particular one of the working cycles; and

when it is determined that an unexpected air pulse has occurred, performing at least one of (a) altering an aspect of control of the engine while the engine is operating in the skip fire mode in response to said determination; and

(b) recording the detection of the unexpected air pulse in a diagnostics system.