METHOD FOR ENGINE LASER IGNITION SYSTEM
First Claim
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1. A method, comprising:
- spinning an engine in reverse, unfueled, to establish a baseline intake air temperature and then sealing a cylinder at a position of negative valve overlap;
operating a laser ignition device in the sealed cylinder;
spinning the engine in reverse, unfueled, to unseal the cylinder; and
diagnosing the laser ignition device based on a change in measured intake air temperature relative to the baseline intake temperature.
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Abstract
Methods and systems are provided for diagnosing a laser ignition system of an engine. In one example, a controller may operate the laser in a sealed cylinder hours after key-off. Then, the cylinder may be unsealed and a change in exhaust temperature may be correlated with laser functionality.
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Citations
20 Claims
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1. A method, comprising:
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spinning an engine in reverse, unfueled, to establish a baseline intake air temperature and then sealing a cylinder at a position of negative valve overlap; operating a laser ignition device in the sealed cylinder; spinning the engine in reverse, unfueled, to unseal the cylinder; and diagnosing the laser ignition device based on a change in measured intake air temperature relative to the baseline intake temperature. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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12. A method for an engine, comprising:
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operating the engine in a vehicle; operating the vehicle to drive in an autonomous driving mode; and
while doing so;operating a laser ignition device in a sealed, unfueled engine cylinder after an engine key-off; during a first condition, comparing a measured exhaust temperature after the operating to a baseline exhaust temperature established via unfueled engine spinning; during a second condition, comparing a measured intake temperature after the operating to a baseline intake temperature established via the unfueled engine spinning and during both the first and second condition, diagnosing the laser ignition device based on the comparing. - View Dependent Claims (13, 14, 15, 16)
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17. An engine system, comprising:
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an engine including a cylinder; a laser ignition device coupled to the cylinder; an intake air temperature sensor coupled to an intake passage of the engine; an electric motor; and a controller with computer-readable instructions stored on non-transitory memory for; waking up a powertrain control module from a sleep mode when a threshold duration has elapsed following an engine key-off; spinning the engine, unfueled via the motor, to establish a baseline intake air temperature; sealing the cylinder by spinning the engine, unfueled via the motor, to a position where all cylinder valves are closed; operating the laser ignition device in the sealed cylinder for a duration; unsealing the cylinder by re-spinning the engine, unfueled via the motor, to a position where at least an intake valve is open; and diagnosing the laser ignition device by comparing an intake air temperature measured after the operating with the baseline intake air temperature. - View Dependent Claims (18, 19, 20)
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Specification