Systems and methods for engine start

A method for restarting an engine of a vehicle in a reverse direction, the method comprising:

• receiving, by an engine control unit, a user request to reverse engine rotation while the engine is running;
• determining, by the engine control unit, that one or more parameters satisfy a predefined condition to perform reverse engine rotation;
• performing, in response to determining that the one or more parameters satisfy the predefined condition and by the engine control unit, an engine reverse process by switching a starter-generator controller to a starter mode;
• applying, by the starter-generator controller, braking torque to a crankshaft of the vehicle by sending excess power to a power source to decelerate a speed of the crankshaft;
• developing, by the starter-generator controller, torque in an opposite direction of a current rotation of the crankshaft by using energy from the power source;
• determining that the crankshaft is rotating in the opposite direction;
• and
• switching, in response to determining that the crankshaft is rotating in the opposite direction, by the engine control unit, the starter-generator controller back to a voltage regulator mode and recharge recharging the power source.