Hi Guys,
Have a read of this link.
Quote from
http://www.autospeed.com/cms/articl...Rail-Diesel-Engine-Management-Part-2&A=108105
Closed Loop Oxygen Sensor Control
As with petrol management systems, diesel management system use oxygen sensor closed loop control. However, in diesel systems a broadband oxygen sensor is used that is capable of measuring air/fuel ratios as lean as 60:1. This Universal Lambda Sensor (abbreviation in German: LSU) comprises a combination of a Nernst concentration cell and an oxygen pump cell.
Because the LSU signal output is a function of exhaust gas oxygen concentration and exhaust gas pressure, the sensor output is compensated for variations in exhaust gas pressure. The LSU sensor output also changes over time and to compensate for this, when the engine is in over-run conditions, comparison is made between the measured oxygen concentration of the exhaust gas and the expected output of the sensor if it were sensing fresh air.
Any difference is applied as a learned correction value.
Closed loop oxygen control is used for short- and long-term adaptation learning of the injected fuel quantity. This is especially important in limiting smoke output, where the measured exhaust gas oxygen is compared with a target value on a smoke limitation map. Oxygen sensor feedback is also used to determine whether the target exhaust gas recirculation is being achieved.
Rappy
Have a read of this link.
Quote from
http://www.autospeed.com/cms/articl...Rail-Diesel-Engine-Management-Part-2&A=108105
Closed Loop Oxygen Sensor Control
As with petrol management systems, diesel management system use oxygen sensor closed loop control. However, in diesel systems a broadband oxygen sensor is used that is capable of measuring air/fuel ratios as lean as 60:1. This Universal Lambda Sensor (abbreviation in German: LSU) comprises a combination of a Nernst concentration cell and an oxygen pump cell.
Because the LSU signal output is a function of exhaust gas oxygen concentration and exhaust gas pressure, the sensor output is compensated for variations in exhaust gas pressure. The LSU sensor output also changes over time and to compensate for this, when the engine is in over-run conditions, comparison is made between the measured oxygen concentration of the exhaust gas and the expected output of the sensor if it were sensing fresh air.
Any difference is applied as a learned correction value.
Closed loop oxygen control is used for short- and long-term adaptation learning of the injected fuel quantity. This is especially important in limiting smoke output, where the measured exhaust gas oxygen is compared with a target value on a smoke limitation map. Oxygen sensor feedback is also used to determine whether the target exhaust gas recirculation is being achieved.
Rappy