Waste-spark engine ignition

Abstract

A distributorless ignition system is provided which includes an ignition coil for firing a pair of first and second spark plugs at the same time. The ignition system includes a changeover switch which, when assuming one operating position, causes the first spark plug to produce negative polarity spark and the second spark plug to produce positive polarity spark and, when assuming another operating position, causes the first spark plug to produce positive polarity spark and the second spark plug to produce negative polarity spark. The operating position of changeover switch is changed every time the number of sparks produced by each of the first and second spark plugs becomes two. By this, the number of negative polarity sparks and the number of positive polarity sparks produced by each of the first and second spark plugs on compression stroke at its corresponding cylinder over a long period of time are the same. This enables the center electrode and ground electrode of each of the first and second spark plugs to wear away equally. An ignition method is also provided.

Dependencies are inferred from the claim text.