Control apparatus of heat exchanging system

A control apparatus of a heat exchanging system, the heat exchanging system comprising:

• a heater core heating system including a heater water passage, through which heat exchanging water circulates, a heat exchanger for heating the heat exchanging water circulating the heater water passage, and a heater pump for circulating the heat exchanging water through the heater water passage, the heater core heating system heating the heater core by the heat exchanging water, the heater core heating air supplied to an interior of a vehicle for warm up the interior of the vehicle;
• an engine cooling system including an engine water passage, through which the heat exchanging water circulates, and an engine pump for circulating the heat exchanging water through the engine water passage, the engine cooling system cooling an internal combustion engine by the heat exchanging water;
• a connection system for connecting the engine water passage and the heater water passage to each other;
• and
• a shut-off valve provided in the heater water passage for shutting off the heater water passage;
• the heater pump and the engine pump being configured to be activated such that a core flow rate corresponding to a flow rate of the heat exchanging water flowing through the heater core, is controlled to a requested core flow rate, and an engine flow rate corresponding to a flow rate of the heat exchanging water flowing through the engine water passage, is controlled to a requested engine flow rate,
• the connection system being configured to connect the engine water passage and the heater water passage to each other such that the heat exchanging water flows into the heater water passage from the engine water passage and flows out from the heater water passage to the engine water passage, and
• the shut-off valve being configured to Shut off a predetermined water passage portion corresponding to a portion of the heater water passage between a portion of the heater water passage, at which the heat exchanging water flows into the heater water passage from the engine water passage, and a portion of the heater water passage, at which the heat exchanging water flows out from the heater passage to the engine water passage,
• the control apparatus comprising an electronic control unit configured to:
• activate the heater pump when a predetermined warm-up condition that warming-up of the interior of the vehicle is requested, is satisfied;
• and
• activate the connection system to connect the engine water passage to the heater water passage, and activate the shut-off valve to shut off the predetermined water passage portion when a predetermined connection condition including the warm-up condition, is satisfied,
• wherein the electronic control unit is configured to execute a control for decreasing a duty ratio of the heater pump after the electronic control unit executes controls for connecting the engine water passage to the heater water passage by the connection system, shutting off the predetermined water passage portion by the shut-off valve, and increasing a duty ratio of the engine pump when the controls for shutting off the predetermined water passage portion by the shut-off valve, connecting the engine water passage to the heater water passage by the connection system, decreasing the duty ratio of the heater pump, and increasing the duty ratio of the engine pump, are requested to be executed.