Patent ID: 7543444

Claim:
An air supply apparatus for an engine comprising a plurality of cylinder groups, each having a plurality of cylinders, a plurality of exhaust pipes connected to the cylinder groups, respectively and catalysts arranged in the exhaust pipes, respectively, the apparatus comprising devices for supplying an air into an interior of the corresponding exhaust pipes upstream of the corresponding catalysts, respectively; and electrical power is supplied to the air supply devices from a common battery, wherein each air supply device comprises at least one electrically-activated air pump, and when a plurality of the air pumps must be activated, the air pumps are activated at different times, and wherein the apparatus comprises a battery for activating the air pumps, and when a plurality of the air pumps must be activated, at least one of the air pumps is activated and when the battery supplies electrical power having a predetermined electrical voltage to the remaining air pumps after the at least one air pump is activated, the remaining air pumps are activated.