Method and system for controlling a hybrid motor vehicle during decelerations

A method for controlling a motor vehicle comprising a combustion engine, a first electric machine and a second electric machine, the combustion engine being connected to the wheels by a disengageable connection and to the second electric machine by a connection that can also be disengaged, the electric machines being electrically connected to a battery, the control method comprising the following steps:

• the driver's torque requirement is determined,
• the power absorbed by the main electric machine to meet the target torque required at the wheels is determined,
• the electrical power to be expended by the second electric machine to meet the target torque required at the wheels is determined by subtracting the power absorbed by the main electric machine from the charging capacity of the traction battery,
• the equivalent mechanical power to be produced by the second electric machine is determined as a function of the electrical power to be expended by the second electric machine and the average electrical efficiency value from mechanical power,
• a gross value is determined for the minimum rotation speed of the combustion engine, modelled by a linear model of the power losses of the combustion engine as a function of the equivalent mechanical power to be produced by the second electric machine, and
• a setpoint for the minimum speed of rotation of the combustion engine is determined from the minimum speed of rotation of the combustion engine as a function of positive and negative gradients.