Abstract: An ignition device at least equipped with a DC power source, an ignition coil unit, a spark plug, an ignition switch, and an auxiliary power source, wherein the auxiliary power source is at least equipped with a discharge energy accumulating means, a discharge switch, and a discharge driver. The ignition device is further equipped with a secondary-current feedback controlling means comprising a secondary current detecting means for detecting a secondary current flowing during the ignition coil unit discharge period, and a secondary current feedback control circuit-for determining an upper limit and a lower limit for the secondary current from binary threshold values, and driving so as to open and close the discharge switch on the basis of the determination results. Furthermore, energy is introduced from the auxiliary power source without switching the polarity of the secondary current.

Abstract: An ignition device includes a spark plug and an ignition coil. The spark plug is attached to a cylinder head such that a center electrode and a ground electrode project into a combustion chamber. In an internal combustion engine, airflow is generated in a predetermined direction to the spark plug during a compression step. The ignition coil has a primary coil and a secondary coil. An output voltage of the secondary coil after interruption of energization of the primary coil is restricted to a predetermined voltage or less. The ground electrode has a leg portion extending from a housing of the spark plug and an opposing portion that extends in a direction intersecting with the leg portion and forms a gap by opposing the center electrode. The leg portion is attached to a position further upstream than the gap in a flow direction of the airflow during the compression step.

Abstract: An ignition device at least equipped with a DC power source, an ignition coil unit, a spark plug, an ignition switch, and an auxiliary power source, wherein the auxiliary power source is at least equipped with a discharge energy accumulating means, a discharge switch, and a discharge driver. The ignition device is further equipped with a secondary-current feedback controlling means comprising a secondary current detecting means for detecting a secondary current flowing during the ignition coil unit discharge period, and a secondary current feedback control circuit-for determining an upper limit and a lower limit for the secondary current from binary threshold values, and driving so as to open and close the discharge switch on the basis of the determination results. Furthermore, energy is introduced from the auxiliary power source without switching the polarity of the secondary current.

Abstract: An ignition system is provided, in which a Zener diode is connected in parallel with a spark plug, to suppress torque variation from becoming large in an engine when deterioration of the spark plug is advanced. Specifically, the ignition system includes a secondary coil having an end connected to a center electrode of the spark plug via a connecting path. The connecting path is connected to a constant-voltage path having a grounded end and including the Zener diode. The time from when an ignition signal is switched off until when ignition timing occurs is measured for a plurality of times. The difference between a maximum value and a minimum value among the plurality of measurements is defined to be a variation range. A breakdown voltage of the Zener diode is adjusted based on requirements such as for rendering the variation range to be a predetermined time or smaller.

Abstract: A control apparatus for an ignition system of an internal combustion engine which can appropriately judge deterioration of a spark plug is disclosed. The ignition system includes a spark plug and a Zener diode. These are connected in parallel. In the ignition system, a constant-voltage path whose one of two ends is grounded is connected to the connecting path which connects the center electrode of the spark plug to a secondary coil. The constant-voltage path includes a Zener diode and a resistor. In a case where electric current is detected at the resister in a term from the start of current supply to a primary coil to the end, the control apparatus judges the spark plug being deteriorated.

Abstract: An ignition apparatus is provided with a Zener diode as a limiter device, which limits a primary voltage of an ignition coil to be less than a Zener voltage, and a switching circuit, which prohibits a limiter function of the Zener diode at a start of discharge and switches the limiter device to perform the limiter function for a predetermined time period following the start of discharge. A secondary voltage is limited to be more than a secondary limit value. Even when blowout arises in discharging, re-discharging is avoided from arising immediately after the blowout and exhaustion of a spark plug caused by repetition of discharging is avoided.

Abstract: An ignition system is provided, which can restrict decreasing of constant-voltage duration of a spark plug and effectively prevents the occurrence of an accidental fire in an engine. A typical ignition system includes a secondary coil having one end connected to a positive side of a battery via a low-voltage side path and the other end connected to a center electrode via a connecting path which connects the secondary coil and the spark plug. A constant-voltage path having a grounded end is connected to the connecting path. A block diode is arranged between the secondary coil and a point where the constant-voltage path is connected with the connecting path. A Zener diode is disposed within the constant-voltage path. Each anode of the block diode and the Zener diode is mutually connected.

Abstract: An ignition device includes a spark plug and an ignition coil. The spark plug is attached to a cylinder head such that a center electrode and a ground electrode project into a combustion chamber. In an internal combustion engine, airflow is generated in a predetermined direction to the spark plug during a compression step. The ignition coil has a primary coil and a secondary coil. An output voltage of the secondary coil after interruption of energization of the primary coil is restricted to a predetermined voltage or less. The ground electrode has a leg portion extending from a housing of the spark plug and an opposing portion that extends in a direction intersecting with the leg portion and forms a gap by opposing the center electrode. The leg portion is attached to a position further upstream than the gap in a flow direction of the airflow during the compression step.

Abstract: An ignition system for an internal-combustion engine includes an ignition coil and an ignition control circuit. The ignition coil includes a primary coil and a secondary coil. The ignition control circuit includes a capacitor. The ignition control circuit employs a capacitor discharged ignition method, whereby the ignition control circuit is configured such that electrical charge, with which the capacitor is charged, is discharged into the primary coil to drive the ignition coil. A coupling coefficient, which indicates a degree of magnetic coupling between the primary coil and the secondary coil, is set in a range of 0.9 to 0.97. k, which is the coupling coefficient, is provided using a formula k=(1?L1?/L1)1/2, wherein L1 is an inductance of the primary coil and L1? is an inductance of the primary coil when the secondary coil is short-circuited.

Abstract: An ignition system for an internal-combustion engine includes an ignition coil and an ignition control circuit. The ignition coil includes a primary coil and a secondary coil. The ignition control circuit includes a capacitor. The ignition control circuit employs a capacitor discharged ignition method, whereby the ignition control circuit is configured such that electrical charge, with which the capacitor is charged, is discharged into the primary coil to drive the ignition coil. A coupling coefficient, which indicates a degree of magnetic coupling between the primary coil and the secondary coil, is set in a range of 0.9 to 0.97. k, which is the coupling coefficient, is provided using a formula k=(1?L1?/L1)1/2, wherein L1 is an inductance of the primary coil and L1? is an inductance of the primary coil when the secondary coil is short-circuited.

Abstract: An internal combustion engine ignition device has a resin layer in a clearance between an insulator and a winding contained in the insulator. The ignition device has a cylindrical insulator and a resin layer. The insulator has an opening portion at one end and a bottom portion at the other end. The insulator contains one of a primary winding and a secondary winding. The resin layer is formed by charging a resin in the clearance between the insulator and one of the windings. The diameter of the inner periphery of the insulator gradually increases from the opening portion to the bottom portion. When the resin layer shrinks from the opening portion toward the bottom portion of the insulator, the resin layer can shrink without getting snagged on the inner periphery of the insulator.

Abstract: An insulator includes a plug side cylindrical portion having an inner space for accommodating a center electrode and a coil side cylindrical portion extending in a direction departing from a combustion chamber. The high-voltage portion of an ignition coil is entirely accommodated inside the coil side cylindrical portion. According to this arrangement, the coil side cylindrical portion can assure insulation between the high-voltage portion and the low-voltage portion. The portion to be insulated and fixed by an insulating resin is limited only to the secondary winding.

Abstract: An internal combustion engine ignition device has a resin layer in a clearance between an insulator and a winding contained in the insulator. The ignition device has a cylindrical insulator and a resin layer. The insulator has an opening portion at one end and a bottom portion at the other end. The insulator contains one of a primary winding and a secondary winding. The resin layer is formed by charging a resin in the clearance between the insulator and one of the windings. The diameter of the inner periphery of the insulator gradually increases from the opening portion to the bottom portion. When the resin layer shrinks from the opening portion toward the bottom portion of the insulator, the resin layer can shrink without getting snagged on the inner periphery of the insulator.

Abstract: An inspection object constructed of an ignition plug and an ignition coil is inserted in an inspection housing that does not have a ground electrode. A voltage generated in the ignition coil is measured while the inspection object is housed in the inspection housing. Electrical discharge does not occur because the ground electrode is not provided. Therefore, the voltage generated in the ignition coil is properly measured for quality inspection of the ignition coil.

Abstract: The ignition device for an internal combustion engine includes two spark plugs provided for each cylinder, ignition coils arranged independently to each of the spark plugs, an ignition power source circuit for supplying electrical energy to first coils which constitute the ignition coils, and an ignition transistor circuit for switching on and off the electrical supply from the ignition power source circuit to the first coils. In the ignition device, the first coils corresponding to spark plugs that are provided to the same cylinder are connected in parallel with the ignition transistor circuit that is arranged to each cylinder. The ignition power source circuit is a circuit including an energy storage condenser for storing electrical energy supplied to the first coil. The electrical supply circuit is a circuit including an MOS-type field effect transistor.

Abstract: An ignition device for an internal combustion engine has a housing, which includes a first case adjacent to the combustion chamber of the engine and a second case away from the combustion chamber. The first case has a flange formed at its end away from the combustion chamber. The second case has a flange formed at its end adjacent to the combustion chamber. The first case flange faces the side of the second case flange that is away from the combustion chamber. A bolt is screwed into the second case to engage the flanges with each other, substantially integrating the cases with each other.

Abstract: The ignition device for an internal combustion engine includes two spark plugs provided for each cylinder, ignition coils arranged independently to each of the spark plugs, an ignition power source circuit for supplying electrical energy to first coils which constitute the ignition coils, and an ignition transistor circuit for switching on and off the electrical supply from the ignition power source circuit to the first coils. In the ignition device, the first coils corresponding to spark plugs that are provided to the same cylinder are connected in parallel with the ignition transistor circuit that is arranged to each cylinder. The ignition power source circuit is a circuit including an energy storage condenser for storing electrical energy supplied to the first coil. The electrical supply circuit is a circuit including an MOS-type field effect transistor.

Abstract: An inspection object constructed of an ignition plug and an ignition coil is inserted in an inspection housing that does not have a ground electrode. A voltage generated in the ignition coil is measured while the inspection object is housed in the inspection housing. Electrical discharge does not occur because the ground electrode is not provided. Therefore, the voltage generated in the ignition coil is properly measured for quality inspection of the ignition coil.

Abstract: An ignition device for an internal combustion engine has a housing, which includes a first case adjacent to the combustion chamber of the engine and a second case away from the combustion chamber. The first case has a flange formed at its end away from the combustion chamber. The second case has a flange formed at its end adjacent to the combustion chamber. The first case flange faces the side of the second case flange that is away from the combustion chamber. A bolt is screwed into the second case to engage the flanges with each other, substantially integrating the cases with each other.

Abstract: An insulator includes a coil side cylindrical portion extending from a plug side cylinder portion in a direction departing from a combustion chamber. One end of the coil side cylindrical portion protrudes in the direction departing from the combustion chamber with respect to a primary winding and a secondary winding. A pressure sensing element is disposed next to the one end of the coil side cylindrical portion. The signal lines of the pressure sensing element are taken out of a casing without passing aside an ignition coil. Thus, the diameter of the casing does not increase. The output signal of the pressure sensing element is not adversely influenced by discharge noises generated from the ignition coil.