Heating control device, control program, fluid heating unit, heating cycle device, and vehicle air conditioner including the same

A heating control device comprising:

• a transistor configured to supply electric power by a switching operation to a heater that generates heat when being energized to heat a coolant supplied to a radiator mounted in a vehicle air conditioner,
• wherein the heating control device controls the switching operation of the transistor based on a heating amount control profile, and adjusts a heating amount from the heater by changing an on/off duty ratio of the transistor,
• wherein the heating amount control profile is a function indicating a relation between a temperature of the coolant and the heating amount from the heater, and includes a decrease portion in which the heating amount decreases as the temperature increases from a low temperature side to a high temperature side across a target temperature of the coolant,
• wherein the decrease portion includes a first decrease portion in which the temperature is in a temperature range equal to or lower than the target temperature and a second decrease portion in which the temperature is in a temperature range equal to or higher than the target temperature, and the first decrease portion and the second decrease portion has the same heating amount at the target temperature,
• wherein the first decrease portion and the second decrease portion each has a negative slope in the function,
• wherein the first decrease portion includes a first region and a second region on the high temperature side with respect to the first region, and
• as negative slopes, a slope of the heating amount control profile at any temperature in the second region is larger than a slope of the heating amount control profile at any temperature in the first region.