In the seat heater of domestic cars they currently use heating wire' as a heating element.
However, the seat heaters using heating wire have the danger of catching fire and the possibility of malfunction due to the cutting of a wire or fire damage. Therefore, if the carbon fiber is used as a heating element of seat heater, you can prevent the damage from the cutting of a wire or fire damage
Domestic care are currently controlling the temperature through the thermostat, and it has the disadvantage that the satisfaction varies depending on the taste of users. For example, if you use the thermostat with 37℃ degree grade (off at 37±3℃, on at 28±3℃), the seat heater raises the temperature until the thermostat is off, and the thermostat is off, the power is cut off and the temperature falls until the thermostat is off.
And when the thermostat is on, the temperature of the seat heater begins to rise until the thermostat is off. Through such repeating operation of on & off, the temperature of the seat heater can be controlled within a certain range of temperature.
However, as for the temperature control method of seat heater through the thermostat, the high and low temperatures are limited by the grade of the thermostat, so the satisfaction of the user can very depending on the use's demand and taste. And because the thermostat does not work from the time when it is off until it is on, it may be possible for the user to have a cold feeling from the seat. To meet such various tastes of users, the temperature control method of seat heater by ECU has been developed.
[The principle of the temperature control of seat heater using ECU]
The components to control the temperature of seat heater are composed of ECU, multi-grade switch and NTC. The principle of temperature control using these components is as follows. NTC, attacted to the inside of the seat heater, plays the role of temperature of the seat heater. And as for the multi-grade switch, when the use set the temperature according to his/her taste, it makes the variable resistance change and then, change the temperature of the seat heater.
[The features of the temperature control of seat heater using ECU]
1. As it uses the multi-grade switch, the range of temperature control is wide, and it is possible to control the temperature by grade according to the user's taste and to maintain the constant temperature that the user wants all the time.
2. The NTC that plays the role of temperature sensor attached to the inside of the seat heater is very small compared to the thermostat and light-weighted, the user does not feel any inconvenience when sitting, and the durability of the seat heater is also increased.
NTC (NEGATIVE TEMPERATURE COEFFICIENT)
It is a device used as various temperature sensors, and it has the feature that as the temperature rises, the electrical resistance decreases, and it is low in price and small in size and very precise, so it is most widely used in the fields of science and industry.
Thermostat control unit of thermostat
It is a temperature control unit of thermostat that prevents overheating of the seat heater and maintains the constant temperature.
ECU (Electronic control unit)
It judges the information on the temperature of the seat heater that is sensed from NTC and controls the electric power to optimize the temperature conditions of the seat heater, so it is an electronic control unit to control the surface temperature of the seat heater.
