A vehicle includes a starter motor, an engine having an output mechanically coupled to the starter motor, a transmission having an input, and an electric machine mechanically coupled to the transmission input. The vehicle further includes a clutch configured to mechanically couple the electric machine and the output of the engine, and at least one controller. The at least one controller is programmed to initiate an engine start based on driver demand. The controller is further configured to enable pressure to the clutch for the engine start if driver demand is less than a calibratable torque value or enable the starter motor for the engine start if the driver demand is greater than a calibratable torque value. The controller may lock the clutch to the output of the engine in response to the speed of the engine being approximately equal to the speed of the electric machine.

Methods and system for providing heat to a vehicle are presented. In one example, a heat pump supplies thermal energy to an engine to reduce engine emissions during engine starting. Further, heating the engine via the heat pump may also reduce engine friction at colder ambient temperatures where oil viscosity may be increased.

A method and an apparatus for controlling a mild hybrid electric vehicle are provided. The method includes detecting data for operating the vehicle and determining a target torque of an engine based on the detected data. Additionally, the method includes determining whether an operating condition of a limiting logic of a combustion torque of the engine is satisfied based on a temperature of coolant of the engine and operating the limiting logic when the operating condition of the limiting logic is satisfied. A first available combustion torque of the engine is determined based on a speed of the engine and the temperature of the coolant when the limiting logic is operated and a target torque of a MHSG is determined based on the target torque of the engine and the first available combustion torque of the engine. The MHSG is then operated to generate the target torque of the MHSG.

A vehicle includes an engine including a crank shaft; a battery; a belt-integrated starter generator (BISG) mechanically coupled to the crank shaft and configured to generate electric power from motion of the engine to charge the battery; and a controller configured to operate the BISG to apply a load to the crank shaft to slow the engine and capture electric power for storage in the battery, wherein an initial magnitude of the load is proportional to a temperature of the engine, responsive to a speed of the BISG or engine achieving a predetermined non-zero threshold, remove the load from the crank shaft, and bring the engine to a stop.

A control device for a hybrid vehicle is provided. When a first drive mode is selected as the drive mode of the hybrid vehicle, a control section shifts the drive mode to a second drive mode when a charge amount of a battery for an electric motor becomes smaller than or equal to a determination charge amount. The first drive mode operates the electric motor while an internal combustion engine is stopped. The second drive mode permits the operation of the internal combustion engine. The control section executes a shifting process when the upper limit system output is lower than or equal to a startup determination output even though the charge amount of the battery is greater than the determination charge amount. The shifting process shifts the drive mode to the second drive mode to start the internal combustion engine.

A method and system for operating a vehicle that includes an integrated starter/generator and a driveline disconnect clutch is described. In one example, the method estimates engine torque as a function of engine temperature during cold engine starts so that if an estimate of engine torque is in error, the integrated starter/generator may still successfully start the engine.

A vehicle includes an engine, a start-stop system configured to stop and restart operation of the engine in response to predetermined triggers, and an auxiliary air conditioning AC system including a controller communicably coupled to the start-stop system. The start-stop system is configured to provide a first indication to the auxiliary AC system indicating ignition of the engine and a second indication to the auxiliary AC system after stopping the engine. The auxiliary AC system is configured to turn off the auxiliary AC system in response to receiving the first indication and restart the auxiliary AC system in response to receiving the second indication.

An engine starting apparatus is provided which is equipped with a starter, an inrush current reducer, and a starter mode switch. The inrush current reducer works to reduce an inrush current flowing through an electric motor installed in the starter when the electric motor is energized. The starter mode switch works to change a starter characteristic that is an output characteristic of the starter continuously or selectively at least between a low-torque/high-speed mode and a high-torque/low-speed mode. The starter mode switch places the starter in the high-torque/low-speed mode at least at a time when a piston of the engine is passing a top dead center, and the engine friction has been just maximized for the first time after the starter is actuated to crank the engine. This shortens a period of time required to start up the engine without sacrificing beneficial effects offered by the inrush current reducer.

A system for starting an internal combustion engine includes a battery system, a charger to receive DC battery power from the battery system and convert the power to a DC charging current, a supercapacitor array having a plurality of supercapacitor cells connected to the charger to receive the DC charging current therefrom, and a motor starter to start the internal combustion engine responsive to a DC input from the supercapacitor array. The charger modifies a voltage of the supercapacitor cells in an on-demand fashion, with the charger programmed to provide DC charging current to the supercapacitor array to hold the supercapacitor cells at a first voltage, receive a bump-up command indicative of an upcoming engine start and, responsive to receiving the bump-up command, provide DC charging current to the supercapacitor array to increase a voltage of the supercapacitor cells temporarily to a second voltage higher than the first voltage.

Starting an internal combustion engine may be difficult as a consequence of the operating conditions of the engine. Even after the engine has started, it may take a long period of time for the engine to reach operating temperatures. In the present disclosure, when engine start difficulty is expected, before starting the engine a forced induction compressor arranged with the engine may be turned on to increase the engine intake air pressure before the engine is started.