An engine automatic stop/restart device includes an ignition-prohibition-decision unit that prohibits an ignition for an engine, which is controlled by the ignition-control unit, when a reverse rotation of the engine is detected based on a crank-angle signal; and an ignition-prohibition-release-decision unit that releases an ignition prohibition, after the ignition is prohibited by the ignition-prohibition-decision unit; in which the ignition-prohibition-release-decision unit releases the ignition prohibition when regular rotational signals of the engine, of which count is greater than or equal to a predetermined count, is detected and an engine revolution number is greater than or equal to a predetermined revolution number, after the reverse rotation of the engine is detected, and before a crank is positioned at a compression top dead center of the engine.

An engine automatic stop/restart device includes an ignition-prohibition-decision unit that prohibits an ignition for an engine, which is controlled by the ignition-control unit, when a reverse rotation of the engine is detected based on a crank-angle signal; and an ignition-prohibition-release-decision unit that releases an ignition prohibition, after the ignition is prohibited by the ignition-prohibition-decision unit; in which the ignition-prohibition-release-decision unit releases the ignition prohibition when regular rotational signals of the engine, of which count is greater than or equal to a predetermined count, is detected and an engine revolution number is greater than or equal to a predetermined revolution number, after the reverse rotation of the engine is detected, and before a crank is positioned at a compression top dead center of the engine.

When the concentration of alcohol is high, the timing of ignition is controlled upon the lapse of a delay time Tig from a reference timing t as a timing when a reference angle ref that is more advanced than a top dead center is detected. It should be noted, however, that the timing of ignition is controlled to a timing when a retarded angle aop is detected, if it is determined that a misfire has occurred.

When the concentration of alcohol is high, the timing of ignition is controlled upon the lapse of a delay time Tig from a reference timing t as a timing when a reference angle ref that is more advanced than a top dead center is detected. It should be noted, however, that the timing of ignition is controlled to a timing when a retarded angle aop is detected, if it is determined that a misfire has occurred.

In an ignition device having high voltage wiring, the ignition device which prevents and/or suppresses the occurrence of serious damage due to an electric shock is provided. In the ignition device which includes: an ignition plug that generates a plasma discharge; a DC/AC conversion device that outputs AC power toward the ignition plug; a DC power supply device which is arranged in a different package from that of the DC/AC conversion device and outputs DC power to the DC/AC conversion device via wiring; and a power circuit breaker that conducts and/or interrupts the output of said DC power supply device, the power circuit breaker interrupts the output of the DC power supply device at least once between ignition operation and ignition operation.

In an ignition device having high voltage wiring, the ignition device which prevents and/or suppresses the occurrence of serious damage due to an electric shock is provided. In the ignition device which includes: an ignition plug that generates a plasma discharge; a DC/AC conversion device that outputs AC power toward the ignition plug; a DC power supply device which is arranged in a different package from that of the DC/AC conversion device and outputs DC power to the DC/AC conversion device via wiring; and a power circuit breaker that conducts and/or interrupts the output of said DC power supply device, the power circuit breaker interrupts the output of the DC power supply device at least once between ignition operation and ignition operation.

In an ignition device having high voltage wiring, the ignition device which prevents and/or suppresses the occurrence of serious damage due to an electric shock is provided. In the ignition device which includes: an ignition plug that generates a plasma discharge; a DC/AC conversion device that outputs AC power toward the ignition plug; a DC power supply device which is arranged in a different package from that of the DC/AC conversion device and outputs DC power to the DC/AC conversion device via wiring; and a power circuit breaker that conducts and/or interrupts the output of said DC power supply device, the power circuit breaker interrupts the output of the DC power supply device at least once between ignition operation and ignition operation.

In an ignition device having high voltage wiring, the ignition device which prevents and/or suppresses the occurrence of serious damage due to an electric shock is provided. In the ignition device which includes: an ignition plug that generates a plasma discharge; a DC/AC conversion device that outputs AC power toward the ignition plug; a DC power supply device which is arranged in a different package from that of the DC/AC conversion device and outputs DC power to the DC/AC conversion device via wiring; and a power circuit breaker that conducts and/or interrupts the output of said DC power supply device, the power circuit breaker interrupts the output of the DC power supply device at least once between ignition operation and ignition operation.

There is provided a controller and a control method for an internal combustion engine capable of correcting a detection error of a crankshaft angle with high accuracy. A controller for an internal combustion engine includes an angle information detector that detects an angle interval and a time interval by a specific crank angle sensor; an angle information correction calculator that corrects the angle interval or the time interval by the correction value; an angle information calculator that calculates a crank angle speed, a crank angle acceleration, and an angular acceleration change amount based on the corrected angle interval and the corrected time interval; and a correction value change calculator that change the correction value so that the angular acceleration change amount approaches zero.

There is provided a controller and a control method for an internal combustion engine capable of correcting a detection error of a crankshaft angle with high accuracy. A controller for an internal combustion engine includes an angle information detector that detects an angle interval and a time interval by a specific crank angle sensor; an angle information correction calculator that corrects the angle interval or the time interval by the correction value; an angle information calculator that calculates a crank angle speed, a crank angle acceleration, and an angular acceleration change amount based on the corrected angle interval and the corrected time interval; and a correction value change calculator that change the correction value so that the angular acceleration change amount approaches zero.