US Patent No. 9,890,732

VALVE FAULT DETECTION


Patent No. 9,890,732
Issue Date February 13, 2018
Title Valve Fault Detection
Inventorship Matthew A. Younkins, San Jose, CA (US)
Shikui Kevin Chen, San Jose, CA (US)
Assignee Tula Technology, Inc., San Jose, CA (US)

Claim of US Patent No. 9,890,732

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.