Abstract:
Misfire detection techniques for a hybrid electric vehicle (HEV) including an internal combustion engine and an electric motor involve utilizing a crankshaft speed sensor configured to generate a crankshaft speed signal indicative of a rotational speed of a crankshaft of the engine that is coupled to the electric motor via a flywheel. The techniques also utilize a controller configured to control the electric motor to provide a vibrational response to dampen disturbances to the crankshaft, receive the crankshaft speed signal, selectively modify the crankshaft speed signal to obtain a modified crankshaft speed signal, and detect a misfire of the engine based on the modified crankshaft speed signal and a set of thresholds including at least one of a negative misfire threshold and a positive vibrational response threshold.
Abstract:
A first computer-implemented diagnostic method can run in response to an imminent deceleration fuel cutoff (DFCO) event. A second computer-implemented diagnostic method can run on engine shutdown. Both diagnostic methods involve controlling fuel injectors and a fuel pump to make the fuel rail pressure change from a desired minimum to a desired maximum. Measurements from the fuel rail pressure sensor at these endpoints can then be used to detect a fault of the fuel rail pressure sensor. One or both diagnostic methods can be implemented.
Abstract:
A method of diagnosing rationality of a humidity sensor output signal determines that the humidity sensor output signal has passed a rationality diagnostic if the output signal is changing sufficiently. If the output signal is not changing sufficiently, the method determines whether it should be changing sufficiently by whether a humidity capacity index determined based on temperature and pressure local to the humidity sensor is changing sufficiently. If the humidity capacity index is changing sufficiently and the humidity sensor output signal is not, the method determines that the humidity sensor output signal has failed a diagnostic check. Upon determining that the humidity sensor output signal has failed the diagnostic check a predetermined number of times, the method determines that the humidity sensor output signal has failed the rationality diagnostic.