Abstract: A heating system that heats the reducing agent supplier for supplying an urea aqueous solution to an exhaust passage of the internal combustion engine in a vehicle includes: a block heater that is provided in a housing formed with a coolant circuit of the internal combustion engine and can be supplied with power of an external power supply; a coolant circulation passage that is branched from the coolant circuit, is disposed in at least a part of the reducing agent supplier, and merges with the coolant circuit again; an on-off control valve that is provided in the middle of the coolant circulation passage; a bypass passage that connects an upstream side and a downstream side of the on-off control valve; and an on-off valve that is provided in the bypass passage.

Abstract: A heating system that heats the reducing agent supplier for supplying an urea aqueous solution to an exhaust passage of the internal combustion engine in a vehicle includes: a block heater that is provided in a housing formed with a coolant circuit of the internal combustion engine and can be supplied with power of an external power supply; a coolant circulation passage that is branched from the coolant circuit, is disposed in at least a part of the reducing agent supplier, and merges with the coolant circuit again; an on-off control valve that is provided in the middle of the coolant circulation passage; a bypass passage that connects an upstream side and a downstream side of the on-off control valve; and an on-off valve that is provided in the bypass passage.