In-vehicle network system and control method for in-vehicle network system

A control method of an in-vehicle network system including a first controller and a second controller positioned hierarchically higher than the first controller, the control method comprising:

• transmitting, to the second controller, a relay control message containing an instruction to turn on or off a relay circuit based on a vehicle state of a vehicle, the relay circuit being disposed on a power supply line to the first controller;
• transmitting, to the second controller, an activation network management (NM) message through a communication bus in response to an activation trigger that requires the second controller to transition to a normal operation mode, the activation NM message causing the second controller to transition from a low-power consumption mode to the normal operation mode and containing an instruction to selectively activate the first controller;
• and
• turning on or off, with a relay control unit of the second controller, the relay circuit based on the instruction contained in the activation NM message until the second controller receives the relay control message.

An in-vehicle network system comprising:

• a first controller;
• a second controller that is positioned hierarchically higher than the first controller, wherein the first controller and the second controller are connected to a communication bus to communicate with each other in a vehicle, and the second controller includes a relay control unit configured to turn on or off a relay circuit (26, 28, 36) that is disposed on a power supply line to the first controller;
• a power supply control master configured to transmit a relay control message to the second controller based on a vehicle state of the vehicle, the relay control message containing an instruction to turn on or off the relay circuit;
• and
• a NM control master configured to transmit an activation network management (NM) message to the second controller through the communication bus in response to an activation trigger that requires the second controller to transition to a normal operation mode, the activation NM message causing the second controller to transition from a low-power consumption mode to the normal operation mode and containing an instruction to selectively activate the first controller, wherein
• the second controller is configured to turn on or off the relay circuit based on the instruction contained in the activation NM message until the second controller receives the relay control message from the power supply control master.