1. Thermistors: Thermistors are semiconductor devices whose electrical resistance changes with temperature. They are typically made of metal oxides or polymers and can be used to measure temperatures from -55°C to +150°C. Thermistors are often used in automotive applications such as engine coolant temperature sensors, intake air temperature sensors, and exhaust gas temperature sensors.
2. Resistance Temperature Detectors (RTDs): RTDs are temperature sensors that use the principle of resistance change with temperature. They are made of a metal, usually platinum, whose electrical resistance increases with temperature. RTDs are more accurate than thermistors and can be used to measure temperatures from -200°C to +600°C. RTDs are often used in automotive applications such as engine oil temperature sensors and transmission fluid temperature sensors.
3. Thermocouples: Thermocouples are temperature sensors that use the Seebeck effect to generate a voltage proportional to the temperature difference between two dissimilar metals. They are made of two dissimilar metal wires, such as copper and constantan, which are joined at one end. When the junction is heated, a voltage is generated between the two wires. Thermocouples can be used to measure temperatures from -200°C to +1800°C. Thermocouples are often used in automotive applications such as exhaust gas temperature sensors and catalytic converter temperature sensors.
4. Infrared Sensors: Infrared sensors measure temperature by detecting the infrared radiation emitted by an object. They are typically made of semiconductor materials, such as lead selenide or indium antimonide, which are sensitive to infrared radiation. Infrared sensors can be used to measure temperatures from -50°C to +500°C. Infrared sensors are often used in automotive applications such as occupant compartment temperature sensors and tire temperature sensors.
5. Capacitive Sensors: Capacitive sensors measure temperature by detecting the change in capacitance between two electrodes as the temperature changes. They are typically made of ceramic materials, such as barium titanate, which have a high dielectric constant. Capacitive sensors can be used to measure temperatures from -40°C to +200°C. Capacitive sensors are often used in automotive applications such as fuel level sensors and humidity sensors.
These are some of the common types of temperature sensors used in automotive applications. The choice of sensor depends on the specific application and the required temperature range.
