Method for optimising the time gradient of the pressure increase in an injection system of a hybrid motor vehicle

A method for optimizing a pressure increase time gradient in a fuel injection system of a hybrid motor vehicle, said hybrid motor vehicle comprising an internal combustion engine and an electric machine, each suitable for generating a predetermined engine torque, said internal combustion engine comprising an injection system with a high-pressure pump, a supply circuit, a common chamber for supplying pressurized fuel and a plurality of injectors supplied with the pressurized fuel in the common chamber,

• said method comprising the following steps, executed by a control unit of the hybrid motor vehicle in response to a first time gradient setpoint of the pressure increase of the fuel in the common fuel supply chamber representative of a predetermined acceleration request of the hybrid motor vehicle:
• a) comparing the first time gradient setpoint with a predetermined threshold value (THD) corresponding to a theoretical maximum capability to generate a pressure increase time gradient by action of the internal combustion engine on the high-pressure pump;
• and, if the first time gradient setpoint is greater than the predetermined threshold value;
• b) determining an additional engine torque value to be generated by the electric machine to allow the high-pressure pump to generate a pressure increase time gradient according to the first time gradient setpoint by action of the internal combustion engine on the high-pressure pump;
• c) determining a first engine torque setpoint, for controlling the electric machine, on the basis of a maximum engine torque value that said electric machine can produce and the additional engine torque value;
• d) transmitting an engine torque request to a control unit of the electric machine on the basis of the first engine torque setpoint;
• e) determining a second engine torque setpoint, for controlling the internal combustion engine, on the basis of the required engine torque associated with the predetermined acceleration command, and the first engine torque setpoint;
• f) determining combustion parameters suitable for causing the generation of engine torque by the internal combustion engine on the basis of the second engine torque setpoint;
• g) determining an available pressure increase time gradient value associated with the second engine torque setpoint;
• and
• h) determining a second pressure increase time gradient setpoint on the basis of the available pressure increase time gradient value, a maximum theoretical pressure increase time gradient value, and the first pressure increase time gradient setpoint.