A step-up converter and an ignition system including a step-up converter are provided, which enable a better automated manufacture and reduced electrical insulation measures by a step-up converter constructed as follows: a transformer including a primary coil and a secondary coil galvanically isolated from the primary coil, the secondary coil being wound in multiple layers, and the primary coil being wound coaxially to the secondary coil over an outermost layer of the secondary coil, a first electrical terminal of the secondary coil branching off from an innermost layer of the secondary coil. The first electrical terminal of the secondary coil is configured for electrical connection to a high-voltage terminal for the spark gap.

An electronic circuit (101) for controlling a spark of a spark plug (SP1) in a capacitor discharge ignition system (100) for a combustion engine. The electronic circuit (101) comprises an ignition coil (110) dimensioned and configured to provide current to the spark plug (SP1), an ignition capacitor (C1) dimensioned and configured to supply energy to the primary winding (L1), an voltage source (130) dimensioned and configured to supply energy to at least one of the ignition capacitor (C1) and the primary winding (L1), a first switch (SW1) connected to the first primary terminal (TL1) and the first source terminal (TS1), a second switch (SW2) connected to the second capacitor terminal (TC2) and the second source terminal (TS2), and a third switch (SW3) connected to the second capacitor terminal (TC2) and the first source terminal (TS1). A capacitor discharge ignition system (100) including the electronic circuit (101) and a combustion engine including the capacitor discharge ignition system (100).

In at least some implementations, a method of operating an ignition system for a combustion engine includes charging an energy storage device during at least a portion of the time when the engine is operating, permitting the level of energy stored on the charge storage device to decrease over time after the engine ceases to operate, determining the energy level on the energy storage device when the engine is restarted after having ceased operating, and setting at least one engine operational parameter as a function of the determined energy level. In at least some implementations, the at least one engine operational parameter may include one or more of: richness of a fuel and air mixture to be delivered to the engine, ignition timing, desired engine idle speed.

An electronic circuit (101) for controlling a spark of a spark plug (SP1) in a capacitor discharge ignition system (100) for a combustion engine. The electronic circuit (101) comprises an ignition coil (110) dimensioned and configured to provide current to the spark plug (SP1), an ignition capacitor (C1) dimensioned and configured to supply energy to the primary winding (L1), an voltage source (130) dimensioned and configured to supply energy to at least one of the ignition capacitor (C1) and the primary winding (L1), a first switch (SW1) connected to the first primary terminal (TL1) and the first source terminal (TS1), a second switch (SW2) connected to the second capacitor terminal (TC2) and the second source terminal (TS2), and a third switch (SW3) connected to the second capacitor terminal (TC2) and the first source terminal (TS1). A capacitor discharge ignition system (100) including the electronic circuit (101) and a combustion engine including the capacitor discharge ignition system (100).

In at least some implementations, a method of operating an ignition system for a combustion engine includes charging an energy storage device during at least a portion of the time when the engine is operating, permitting the level of energy stored on the charge storage device to decrease over time after the engine ceases to operate, determining the energy level on the energy storage device when the engine is restarted after having ceased operating, and setting at least one engine operational parameter as a function of the determined energy level. In at least some implementations, the at least one engine operational parameter may include one or more of: richness of a fuel and air mixture to be delivered to the engine, ignition timing, desired engine idle speed.

An ignition control device is provided with an ignition coil including a primary coil and a secondary coil, a main ignition circuit performing a main ignition operation, an energy input circuit that performs an energy input operation for superposing a current having the same polarity to a secondary current, in which a signal generation circuit is provided to generate, based on a main ignition signal that controls the main ignition operation, at least one of an energy input signal controlling the energy input operation and a target secondary current command signal commanding a target secondary current value.

An ignition control device is provided with an ignition coil including a primary coil and a secondary coil, a main ignition circuit performing a main ignition operation, an energy input circuit that performs an energy input operation for superposing a current having the same polarity to a secondary current, in which a signal generation circuit is provided to generate, based on a main ignition signal that controls the main ignition operation, at least one of an energy input signal controlling the energy input operation and a target secondary current command signal commanding a target secondary current value.

An ignition apparatus performs energy input control in which energy is continuously inputted to an ignition coil to enable a spark discharge in a predetermined energy input period after interrupting a primary current by an ignition switch and generating a discharge of a spark plug by a secondary current. A combustion state determination circuit determines a combustion state by comparing a combustion pressure P detected by a combustion state detector. When the combustion pressure P is smaller than a second threshold Pth2, and there is room for improving the combustion state with respect to the present energy input condition, the energy input period IGW is increased or a target secondary current I2* is increased. By compensating the condition of the energy input control in accordance with the combustion state, a target combustion state can be achieved with just enough energy consumption.

A step-up converter and an ignition system including a step-up converter are provided, which enable a better automated manufacture and reduced electrical insulation measures by a step-up converter constructed as follows: a transformer including a primary coil and a secondary coil galvanically isolated from the primary coil, the secondary coil being wound in multiple layers, and the primary coil being wound coaxially to the secondary coil over an outermost layer of the secondary coil, a first electrical terminal of the secondary coil branching off from an innermost layer of the secondary coil. The first electrical terminal of the secondary coil is configured for electrical connection to a high-voltage terminal for the spark gap.

A maximum value of a discharge current from a capacitor 13, detected by a primary-side current detection means 24 disposed at a grounded end of the capacitor 13, is controlled such as not to exceed a predetermined first control value Y1. The first control value Y1 is derived based on magnetic saturation of a primary winding 3, with the control being performed by controlling the on-off state of an energy injection switching means 20. As a result, magnetic saturation of the primary winding 3 can be prevented, and the reliability of an ignition apparatus which incorporates an energy injection circuit 6 can be increased.