US Patent No. 9,562,470

VALVE FAULT DETECTION


Patent No. 9,562,470
Issue Date February 07, 2017
Title Valve Fault Detection
Inventorship Matthew A. Younkins, San Jose, CA (US)
Shikui Kevin Chen, San Jose, CA (US)
Li-Chun Chien, Milpitas, CA (US)
Masaki Nagashima, Pacific Grove, CA (US)
John W. Parsels, San Jose, CA (US)
Geoff Routledge, Gilroy, CA (US)
Assignee Tula Technology, Inc., San Jose, CA (US)

Claim of US Patent No. 9,562,470

1. A method comprising:
operating an engine having a plurality of cylinders in a skip fire mode, the engine including at least one cylinder, each
cylinder having at least one associated intake valve and one associated exhaust valve;

estimating an expected net torque during a selected operating window utilizing a torque model, wherein the torque model considers
an expected torque contribution from each of the cylinders and accounts for the effects of specific skip fire firing decisions
that affect the expected torque contribution from each cylinder during the selected operating window;

directly or indirectly measuring a parameter indicative of actual engine torque during the selected operating window;
determining whether a valve actuation fault has occurred based at least in part on a comparison of the measured parameter
to an expected parameter value that is based at least in part on the expected net torque, wherein the determination is made
within one engine cycle of the occurrence of the valve actuation fault; 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.