Method and system for knock sensor diagnostic
AssigneeFord Global Technologies, LLC
InventorAed Dudar
Life of this patent
Estimating the term…
Abstract
Methods and systems are provided for diagnosing a knock sensor of an engine system by actively inducing knock in an engine cylinder. A laser ignition device is operated in an engine cylinder located closest to the knock sensor while the engine is at rest and with the cylinder parked with an intake valve and an exhaust valve closed to generate and trap heat in the cylinder. Spark timing is advanced in the cylinder on the subsequent restart, which in combination with the trapped heat induces knock, and elicits a response from a functional knock sensor.
Claims20
A method for an engine, comprising:
- inducing a knock event in a cylinder via operation of a laser ignition device;
- and
- diagnosing a knock sensor based on knock sensor output following the induced knock event.
A method, comprising:
- operating a laser ignition system in an unfueled cylinder while an engine is at rest, the cylinder parked in a position with each of an intake and an exhaust valve closed;
- restarting the engine by resuming fueling to the cylinder with spark timing advanced;
- and
- indicating knock sensor degradation responsive to lower than threshold knock sensor output following the restarting.
A vehicle system, comprising:
- an engine including a cylinder, the cylinder having a laser ignition device and a fuel injector;
- a knock sensor coupled to an engine block;
- and
- a controller with computer readable instructions stored on non-transitory memory for:
- disabling fuel to an engine and spinning the engine to rest with the cylinder parked in a position with an intake and an exhaust valve closed;
- operating the laser ignition device coupled to the cylinder to raise cylinder temperature to above a threshold temperature;
- resuming fuel delivery to the engine and combusting fuel in the cylinder with an amount of spark timing advance;
- and
- indicating degradation of the knock sensor based on sensor output following the resuming.
Dependencies are inferred from the claim text.