# Using the Spark Plug as a Sensor for Analyzing the State of the Combustion System

## TL;DR

This paper introduces a new way to monitor engine health by using spark plugs as sensors, helping to detect wear and improve diagnostics.

## Contribution

The novel contribution is using spark plugs as non-contact sensors to monitor combustion system states in real time.

## Key findings

- Increasing spark plug gap shortens arc duration and increases breakdown voltage linearly.
- Breakdown voltage decreases with increasing temperature.
- Electric field magnitude correlates with spark plug gap in non-contact measurements.

## Abstract

This article presents a method that uses a spark plug as a sensor to monitor an internal combustion engine. In addition, the voltage sensors measured the high voltage at the spark plugs using a non-contact method. Monitoring can now be performed in a simple way in real time, along with data processing. This method can be effectively used for the monitoring of all cylinders in an internal combustion engine as well as supplementing other measurement methods to optimize engine maintenance and enable correct diagnostic decisions to be made. Experimental analysis focused on the effect of the spark plug gap on the arc duration, flashover voltage, and high-voltage waveforms. It was found that with an increasing gap, the arc duration is shortened, and the breakdown voltage increases linearly, indicating wear of the spark gap. With increasing temperature, the breakdown voltage value decreased. Non-contact measurements at different frequencies showed a relationship between the magnitude of the electric field and the spark plug gap.