A system for a vehicle includes an electric machine configured to transfer power between an engine and traction battery, an auxiliary battery electrically connected with and isolated from the traction battery, and a controller programmed to, after receiving an engine start request, initiate an engine start using the batteries in response to available traction battery power being below a threshold, and initiate the engine start using the traction battery but not the auxiliary battery otherwise.

A powertrain system including an electric machine rotatably coupled to a crankshaft of an internal combustion engine via a belt is described, wherein the electric machine is disposed to generate torque. A method for controlling the electric machine includes monitoring rotational position of the electric machine, and periodically executing a speed observer to determine a rotational speed of the electric machine based upon the monitored rotational position of the electric machine. An acceleration observer is periodically executed to determine an acceleration rate, wherein the acceleration rate is determined based upon a time-based change in the rotational speed of the electric machine. A virtual inertia term is determined based upon the acceleration rate, and a torque compensation term is determined based upon the virtual inertia term and the acceleration rate. The electric machine is controlled to generate torque based upon the torque compensation term.

Systems and methods for operating an engine that may be rotated by an electric machine during engine starting are described. In one example, an amount of electric current that is available to rotate the engine via the electric machine may be adjusted in response to an indication that a vehicle that includes the engine may be parked in a geographical area that may be flooded.

An interior permanent magnet electric machine includes a stator having a plurality of teeth disposed around a circumference oriented radially towards a center defining slots interposed between each of the teeth, and a conductive winding wrapped around each of the teeth of the stator to receive an electrical current. The electric machine also includes a rotor which is rotatable relative to the stator. The rotor defines a plurality of openings to receive permanent magnets near an outer portion of the rotor and a number of spokes interposed between mass reduction cutouts located closer to the center relative to the permanent magnets. Each of the permanent magnets defines a magnetic pole and each of the spokes is circumferentially aligned with one of the magnetic poles.

Systems and methods for starting an engine of a hybrid vehicle are described. In one example, the method uses the engine to generate larger amounts of thermal energy while the engine is rotated under power of an electric machine. The systems and methods described herein may be applied to series and parallel hybrid vehicles.

A control apparatus includes a first determination section determining whether a power-supply voltage has decreased below a first threshold value, an interruption section interrupting a current flow to an inverter if the voltage has decreased below the first threshold value, a second determination section that determining whether the power-supply voltage has increased above a second threshold value, an interruption releasing section releasing the interruption based on the fact that the voltage has increased above the second threshold value, a count section counting the number of interruptions, a limiting section determining whether the decrease in the power-supply voltage is caused by a first factor of an electric rotating machine or a second factor, and limits the counting if the decrease in the power-supply voltage is caused by the second factor, and a third determination section determining whether the interruption is allowed to be released based on the number of interruptions.

A belt slip monitor system and method configured to determine whether a belt coupled to a motor-generator is slipping based on operational states of first and second movable portions of the belt slip monitor, wherein the operational states of the first and second movable portions are dependent upon the tension in the belt.

According to some embodiments, a start-stop system for a vehicle is disclosed. The start-stop system includes a first energy storage device coupled to a starter motor. The start-stop system also includes a first DC-to-AC inverter coupled to the first energy storage device, a starter/alternator coupled to the first DC-to-AC inverter, and a second DC-to-AC inverter coupled to the starter/alternator. The start-stop system further includes a second energy storage device coupled to the second DC-to-AC inverter. The start-stop system finally includes a controller configured to control the two DC-to-AC inverters such that either the starter motor or starter/alternator starts the vehicle based on the state of charge of the second energy storage device.

A motor vehicle includes a hybrid drive having an internal combustion engine and an electric drive motor, and an air conditioning system having a compressor configured to compress a refrigerant, and an electric motor configured to operate the compressor and to start the internal combustion engine as electric starter when being coupled with the internal combustion engine. The electric motor has an inverter to operate the electric motor directly with high voltage of a high-voltage onboard electrical system of the motor vehicle so as to enable the electric motor to apply a mechanical torque for re-staring the internal combustion engine in case of need in the absence of any assistance from the electric drive motor. A clutch device mechanically couples the electric motor of the air conditioning system with the internal combustion engine in response to a control signal.

A method of starting a vehicle may include, in response to an expected driver entry, stroking a clutch configured to couple an engine to an electric machine for a predetermined time period. The method may further include, in response to an engine start request received during the predetermined time period, providing power to the electric machine to spin the electric machine at a speed at least equal to a target engine cranking speed.