A method for detecting glow plug replacement or an aging glow plug. The glow plugs are heated and monitored. When a threshold value is reached for a first glow plug, a first value of a temperature-dependent variable is measured for all other glow plugs and is stored as reference values associated with the first glow plug. This process is repeated until reference values associated with each glow plug have been determined and stored for each glow plug. The process is repeated to determine a set of comparative values. The comparative values are compared with the reference values. A deviation of a comparative from a reference value of less than a specified tolerance value is considered an agreement. The inventive process concludes which of the glow plugs of the engine are unaltered and which have a resistance-temperature characteristic that has been altered to an extent indicating replacement, aging or a defect.

An ignition testing system including a test article testing chamber, and at least one gas mixture verification chamber being communicably coupled to the test article testing chamber and being configured to verify at least a content of a gas mixture content provided to the test article testing chamber.

An ignition testing system including a test article testing chamber, and at least one gas mixture verification chamber being communicably coupled to the test article testing chamber and being configured to verify at least a content of a gas mixture content provided to the test article testing chamber.

A spark plug inspection method and a spark plug manufacturing method that enable evaluation for the position of a ground electrode of a tapered-seat-type spark plug. The spark plug inspection method includes: a contact step of screwing an external thread of a metal shell to an internal thread of a gauge so as to bring a part of a tapered portion of the metal shell into line-contact or point-contact with an inner edge of the gauge; and a determination step of determining whether or not a ground electrode is present within a predetermined range in a circumferential direction of the gauge when the tapered portion comes into line-contact or point-contact with the inner edge of the gauge in the contact step.

A spark plug inspection method and a spark plug manufacturing method that enable evaluation for the position of a ground electrode of a tapered-seat-type spark plug. The spark plug inspection method includes: a contact step of screwing an external thread of a metal shell to an internal thread of a gauge so as to bring a part of a tapered portion of the metal shell into line-contact or point-contact with an inner edge of the gauge; and a determination step of determining whether or not a ground electrode is present within a predetermined range in a circumferential direction of the gauge when the tapered portion comes into line-contact or point-contact with the inner edge of the gauge in the contact step.

A failure diagnosis device for an ignition circuit, comprising: an ignition plug; an ignition coil; a capacitor series connection including a high side capacitor and a low side capacitor; a switching-element series connection including a high side switching element and a low side switching element; an inter-terminal voltage detection unit for detecting an inter-terminal voltage of the capacitor series connection; an intermediate voltage detection unit for detecting an intermediate voltage at the connection point of the high side capacitor and the low side capacitor; and a determination unit for determining a failure location of the ignition circuit based on at least one of the inter-terminal voltage and the intermediate voltage.

A failure diagnosis device for an ignition circuit, comprising: an ignition plug; an ignition coil; a capacitor series connection including a high side capacitor and a low side capacitor; a switching-element series connection including a high side switching element and a low side switching element; an inter-terminal voltage detection unit for detecting an inter-terminal voltage of the capacitor series connection; an intermediate voltage detection unit for detecting an intermediate voltage at the connection point of the high side capacitor and the low side capacitor; and a determination unit for determining a failure location of the ignition circuit based on at least one of the inter-terminal voltage and the intermediate voltage.

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.

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.

An electronic device for the ignition system of an engine, which may incorporate circuitry for voltage amplification via transformer action, while also containing circuitry for sensing operational parameters, circuitry for calculation of derived values from the sensed data or operational parameters, circuitry for storage of the data and derived values, circuitry for engine system control, and circuitry for the wireless communication of data and derived values.