A first electric power generation device configured to produce an accessory voltage according to a first instruction voltage. A second electric power generation device configured to produce the accessory voltage according to a second instruction. An electric control unit is configured to execute crank position stop control for stopping a crank of the engine at a target position when the engine is stopped by controlling the first electric power generation device such that a current is circulated in the first electric power generation device and the rotating electric machine generates braking torque. The electric control unit is configured to execute the crank position stop control in a state in which the second instruction voltage is equal to or higher than the first instruction voltage.

A vehicle power supply system, mounted on a vehicle including an internal combustion engine, includes: a main power supply system including a main low-voltage power supply; and a backup power supply system including a backup low-voltage power supply. A starter motor that starts the internal combustion engine is connected to the main power supply system. At least one of a vehicle control device, configured to control the main power supply system, the backup power supply system, the internal combustion engine and the starter motor, and a backup power supply control device of the backup power supply system is configured to execute an abnormality determination processing of determining whether an abnormality occurs in the main power supply system, and does not execute the abnormality determination processing when the starter motor is in operation, or determines that no abnormality occurs in the main power supply system in the abnormality determination processing.

A starting module for a vehicle is provided. The starting module is configured to reside on-board the vehicle, and is used to start an engine associated with the vehicle in the event the battery on the vehicle is too weak to crank the engine. The engine starting module first comprises a housing. The housing resides proximate the vehicle battery and holds a plurality of super capacitors. The super capacitors reside within the housing, are configured in series, and are electrically in parallel with the vehicle battery. The super capacitors store charge received from the electrical system of the vehicle. The starting module also includes control logic. The control logic controls the discharge of stored energy from the super capacitors. The engine starting module also comprises an isolation switch, configured to move between open and close positions in response to signals from the control logic in order to restore charge to the battery as needed.

A method for controlling a start of a mild hybrid vehicle that includes an engine, a starter-generator starting the engine or generating electricity by an output of the engine, a starter starting the engine, and a battery supplying electric power to the starter-generator may include: determining, by a controller configured for controlling an operation of the vehicle, whether a start of the vehicle is requested; checking, by the controller, current limit data of the battery when the start of the vehicle is requested; checking, by the controller, start torque current data of the starter-generator according to state data of the vehicle; comparing, by the controller, the current limit data with the start torque current data; and starting, by the controller, the engine using the starter-generator or the starter according to a result of the comparing, by the controller, the current limit data with the start torque current data.

A hybrid vehicle includes: an engine; a motor; a drive system battery connected to a drive system power line; an auxiliary system battery connected to an auxiliary system power line; a bidirectional power converter configured to step down power on the drive system power line to supply the stepped-down power to the auxiliary system power line, and configured to boost power on the auxiliary system power line to supply the boosted power to the drive system power line; and a control device. The control device is configured to, upon a cold start in which the engine is started, control the engine, the motor, and the bidirectional power converter to cause the motor to crank the engine while causing the bidirectional power converter to boost the power on the auxiliary system power line to supply the boosted power to the drive system power line.

A monitoring method includes, among other things, within a vehicle, providing a first electrical system with an auxiliary battery, and a second electrical system with a primary battery. The method further includes electrically coupling the first electrical system to the second electrical system, electrically loading the auxiliary battery and the primary battery, and comparing an electrical parameter of the auxiliary battery to a threshold value to assess a state of the auxiliary battery.

A system in a vehicle includes a starter motor to start an engine of the vehicle and a battery configured to power the starter motor during the start of the engine. An ultracapacitor is controllably connected in series with the battery to provide additional power to the starter motor during the start of the engine.

A booster is mounted on a vehicle having an idle stop function. The booster boosts an input voltage supplied from a battery, and outputs the boosted input voltage to an in-vehicle device. The booster includes a booster circuit and an output voltage sensor. The booster circuit is a chopper-type, and includes a reactor having one end connected to the battery and a switching element connected between an other end of the reactor and a ground. The output voltage sensor detects an output voltage of the booster circuit.

A vehicle power supply system and a method for operating the same are provided. The vehicle power supply system includes a main battery and a sub-battery to supply power to an electronic load inside a vehicle, and a controller to control supplying of the power to the electronic load using at least one of the main battery or the sub-battery, by monitoring the main battery and the sub-battery. The controller determines whether the main battery allows entrance into Idle Stop and Go, determines whether the sub-battery is able to assist the ISG, and controls the sub-battery to assist the main battery to supply the power to the electronic load, when the main battery allows the entrance into the ISG, when the sub-battery is able to assist the ISG, and when entering into the ISG.

Systems and methods for starting and restarting an engine of a vehicle are disclosed. Power systems for an engine are disclosed.