| 主权项 |
1. An ignition system comprising:
a spark plug that ignites fuel-air mixture in a cylinder of an engine; a DC power supply; an ignition coil that has a primary winding of which a high-voltage side terminal at one end is connected to the DC power supply and a secondary winding that is wound having a secondary number of turns with a predetermined winding ratio with respect to a primary number of turns of the primary winding, and generates a high secondary voltage in the secondary winding according to increase or decrease of a primary current flowing through the primary winding, and the spark plug is connected to a plug-side terminal that is one end of the secondary winding; a control circuit section that controls discharge to the spark plug from the ignition coil; and an electronic control unit that generates an ignition signal that controls ignition timing according to operating conditions of the engine and a discharge period signal that controls a start of discharging from an auxiliary power supply; wherein, the control circuit section includes an auxiliary power supply having an energy storage coil that is charged at least by the DC power supply; an ignition switch that has a control terminal for ignition, a power supply side terminal for ignition, and a ground side terminal for ignition, the ignition switch is a semiconductor element configured to control opening and closing of conduction between the power supply side terminal for ignition and the ground side terminal for ignition based on the ignition signal inputted to the control terminal for ignition, and the power supply side terminal for ignition of the ignition switch is connected to a ground side terminal on another end of the primary winding and the ground side terminal for ignition is grounded, and controls the start of discharging from the ignition coil to the spark plug by controlling the opening and closing of conduction from the DC power supply to the ignition coil; a charging switch that has a control terminal for charging, a power supply side terminal for charging, and a ground side terminal for charging, and the charging switch is a semiconductor element configured to control opening and closing of conduction between the power supply side terminal for the charging and the ground side terminal for the charging based on a charging control signal inputted to the control terminal for the charging; a discharging switch controls the discharge to the ignition coil from the auxiliary power supply, the charging switch has a control terminal for discharging), a power supply side terminal for discharging, and a ground side terminal for discharging, and the discharging switch is a semiconductor element configured to control opening and closing of conduction between the power supply side terminal for discharging and the ground side terminal for discharging based on a discharging control signal inputted to the control terminal for discharging; a driver circuit section that controls the opening and closing of the ignition switch, the charging switch, and the discharging switch in accordance with the ignition signal and the discharge period signal; and an auxiliary energy requirement determiner that determines whether or not an energy charge from the auxiliary power supply is necessary; wherein, when the auxiliary energy requirement determiner determines that the discharge from the auxiliary power supply is necessary during the ignition discharge of the spark plug that has been started by turning the ignition switch off, in addition to storing electromagnetic energy in the energy storage coil by turning the charging switch on, a secondary current flowing through the secondary winding is increased or decreased by varying the primary current by supplying the electromagnetic energy to a low voltage side terminal of the primary winding from the auxiliary power supply by controlling the opening and closing of the charging switch and the discharging switch. |
