How to Use EGT Sensors: Examples, Pinouts, and Specs

Exhaust Gas Temperature (EGT) Sensors are precision devices designed to measure the temperature of exhaust gases in internal combustion engines. These sensors play a critical role in monitoring engine performance, optimizing fuel efficiency, and ensuring compliance with emissions regulations. By providing real-time temperature data, EGT sensors help prevent engine damage caused by excessive heat and enable fine-tuning of engine parameters for improved performance.

• Automotive engines for performance tuning and emissions control
• Aircraft engines for monitoring exhaust gas temperatures
• Industrial machinery and power generation systems
• Marine engines for thermal management
• Turbocharged engines to prevent overheating and optimize boost levels

Below are the key technical details for the EGT sensor manufactured by EGT, with part ID: EGT.

• Measurement Range: -40°C to 1,200°C (-40°F to 2,192°F)
• Accuracy: ±1% of the measured value
• Response Time: < 100 ms
• Output Signal: Millivolt signal (typical for thermocouples, e.g., Type K)
• Operating Voltage: N/A (passive sensor, requires external amplifier)
• Connector Type: Standard thermocouple connectors or custom harness
• Material: Stainless steel probe with ceramic insulation
• Probe Length: 50 mm to 200 mm (varies by model)
• Thread Size: M8 x 1.0 or M10 x 1.0 (varies by model)

The EGT sensor typically uses a two-wire configuration for its thermocouple output. Below is the pinout description:

Note: Wire colors may vary depending on the manufacturer or region. Always refer to the specific datasheet for your sensor model.

1. Connect the Sensor:
   • Attach the yellow wire (positive) to the positive input of a thermocouple amplifier or ADC (Analog-to-Digital Converter).
   • Attach the red wire (negative) to the ground or negative input of the amplifier/ADC.
2. Amplify the Signal:
   • Since the EGT sensor outputs a small millivolt signal, use a thermocouple amplifier (e.g., MAX31855 or AD8495) to amplify the signal for further processing.
3. Read the Data:
   • Connect the amplified signal to a microcontroller (e.g., Arduino UNO) to read and process the temperature data.
4. Calibrate the Sensor:
   • Perform calibration using known temperature points to ensure accurate readings.
5. Install the Sensor:
   • Mount the sensor in the exhaust manifold or downpipe using the appropriate thread size. Ensure the probe is securely fastened and exposed to the exhaust gas flow.

• Placement: Install the sensor as close to the exhaust manifold as possible for accurate readings.
• Heat Protection: Use heat-resistant wiring and connectors to prevent damage from high temperatures.
• Signal Noise: Minimize electrical noise by using shielded cables and proper grounding.
• Amplifier Selection: Choose an amplifier compatible with the thermocouple type (e.g., Type K).
• Avoid Over-Tightening: When installing the sensor, avoid over-tightening to prevent damage to the threads or probe.

Below is an example of how to interface an EGT sensor with an Arduino UNO using a MAX31855 thermocouple amplifier:

#include <Adafruit_MAX31855.h>

// Define the pins for the MAX31855 amplifier
#define DO_PIN 3  // Data Out pin
#define CS_PIN 4  // Chip Select pin
#define CLK_PIN 5 // Clock pin

// Create an instance of the MAX31855 library
Adafruit_MAX31855 thermocouple(CLK_PIN, CS_PIN, DO_PIN);

void setup() {
  Serial.begin(9600);
  Serial.println("EGT Sensor Test");

  // Check if the thermocouple amplifier is connected
  if (!thermocouple.begin()) {
    Serial.println("Error: MAX31855 not detected. Check wiring!");
    while (1);
  }
}

void loop() {
  // Read the temperature in Celsius
  double temperature = thermocouple.readCelsius();

  // Check for errors
  if (isnan(temperature)) {
    Serial.println("Error: Failed to read temperature!");
  } else {
    // Print the temperature to the Serial Monitor
    Serial.print("Exhaust Gas Temperature: ");
    Serial.print(temperature);
    Serial.println(" °C");
  }

  delay(1000); // Wait 1 second before the next reading
}

Note: Ensure the MAX31855 library is installed in your Arduino IDE. You can install it via the Library Manager.

1. No Signal or Incorrect Readings

   • Cause: Loose or incorrect wiring.
   • Solution: Verify the connections between the sensor, amplifier, and microcontroller. Ensure the positive and negative terminals are correctly connected.

2. Fluctuating or Noisy Readings

   • Cause: Electrical noise or poor grounding.
   • Solution: Use shielded cables and ensure proper grounding of the circuit.

3. Sensor Overheating

   • Cause: Installed too close to the exhaust port or in an area with excessive heat.
   • Solution: Reposition the sensor to a location within its operating temperature range.

4. Amplifier Not Detected

   • Cause: Faulty amplifier or incorrect wiring.
   • Solution: Check the amplifier connections and ensure it is powered correctly.

Q1: Can I use the EGT sensor with other microcontrollers besides Arduino?
A1: Yes, the EGT sensor can be used with any microcontroller that supports thermocouple amplifiers, such as Raspberry Pi, ESP32, or STM32.

Q2: How do I clean the EGT sensor?
A2: Use a soft cloth and a mild cleaning solution to remove soot or debris. Avoid abrasive materials that could damage the probe.

Q3: What happens if the sensor is exposed to temperatures beyond its range?
A3: Prolonged exposure to extreme temperatures may damage the sensor or reduce its accuracy. Always operate within the specified range.

Q4: Can I extend the sensor wires?
A4: Yes, but use thermocouple extension wires of the same type (e.g., Type K) to maintain accuracy.

By following this documentation, you can effectively integrate and troubleshoot EGT sensors in your projects.