Sootiness and fouling detection device of spark plug

Abstract

The invention provides a sootiness and fouling detection device of a spark plug, which is capable of detecting carbonaceous sediments and metal sediments in advance with high accuracy. The sootiness and fouling detection device (26) comprises a bias circuit (24) applying bias circuit on the spark plug (1), a current detection circuit (25) which is connected to the bias circuit (24) for detecting current flowed in the spark plug (1), an engine controlling means (3) which calculates an insulation resistance of the spark plug (1) based on the current detected by the current detection circuit (25) and send an igniting instruction signal to a transistor (23), and a warning monitor (5) which sends warnings based on output signals emitted by the engine controlling means (3). The variance of insulating resistance generated with the change of running areas of the engine is detected to determine whether metal sediments are adhered.

Description

technical field [0001] The present invention relates to a smoke stain detection device for a spark plug which detects smoke generated by deposits attached to the spark plug of an internal combustion engine. Background technique [0002] As an ignition device of an engine, a method in which a high voltage generated by an ignition coil is generally applied to a spark plug disposed on a head cover of the engine such that an ignition portion directly protrudes into a combustion chamber is used. [0003] Spark plugs for such ignition devices, for example, such as Figure 10 As shown, it includes: an insulator 12, the insulator 12 is held in a cylindrical mounting fitting 11; a center electrode 13, the center electrode 13 is held inside the insulator 12, and the front end protrudes from the front end of the insulator 12; and a ground electrode 14 , the ground electrode 14 is opposite to the center electrode 13 with a predetermined spark gap therebetween. The center electrode 13 a...

AI Technical Summary

Problems solved by technology

[0013] However, in the ignition device for an internal combustion engine disclosed in Patent Document 1, if the operation such that the temperature of the spark plug is raised despite metal deposits adhering to the spark plug is performed, the metal deposits cause a decrease in insulation resistance instead, and there is a possibility that Possible problems with catalyst breakage due to misfire

[0014] In addition, in the smoke detection device for spark plugs in Patent Document 2, since the insulation resistance value of the spark plug is detected as smoke from a fire, it is only determined whether it is carbonaceous deposits or metal deposits. Operators operating at high speeds and high loads have less opportunity to identify metal deposits and may not be able to properly warn the operator in advance

If the smoke judgment value is increased to detect smoke in advance, it is impossible to distinguish between carbonaceous deposits and metal deposits, which may lead to misjudgment

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