Closed loop fuel injection have been in use for two decades but it’s not until the recent five years that the wide band lambda sensor have been utilized. The goal is to explain wide band and discrete lambda sensors in a simple but powerful way. Both sensors are modeled by simple mathematics and accounts for Oxygen, Hydrogen and Carbon monoxide influences.
The focus is not just on the output from the sensors, but also on the underlying function. This means that all explanations are thorough and methodical.The function of a wide band lambda sensor is more complicated than a discrete type lambda sensor, therefore it’s harder to get correct readings. The model of the wide band lambda sensor is used to evaluate different problems in preparation for the development of an observer.Several potential problem sources are tested and investigated, these include calibration error, pressure error, air leak error, gas sensitivity and fuel errors. To evaluate the potential problems and their ability to explain differences between actual lambda and sensor output, two sensors with differing outputs have been used. The final result is implemented in an ECU.
Source: Linköping University
Author: Jakobsson, Thommy