Do diesel engines have oxygen sensors?

Diesel engines typically do not have oxygen sensors. Unlike gasoline engines, diesel engines operate on a different fuel-air mixture and combustion process. In diesel engines, the fuel is injected directly into the combustion chamber at high pressure, where it mixes with the compressed air and ignites spontaneously due to the heat and pressure.

Gasoline engines, on the other hand, use spark plugs to ignite the fuel-air mixture, and they rely on oxygen sensors to monitor the exhaust gas and ensure that the air-fuel ratio is correct. Oxygen sensors detect the amount of oxygen in the exhaust gas, and this information is used by the engine's electronic control unit (ECU) to adjust the fuel injection and maintain optimal combustion.

Diesel engines do not require oxygen sensors because the fuel injection system is controlled differently. They use various sensors, such as temperature sensors, pressure sensors, and airflow sensors, to monitor the engine's operating conditions and adjust the fuel injection accordingly.

Additionally, diesel engines operate with a lean air-fuel mixture compared to gasoline engines, meaning there is less excess oxygen in the exhaust gas that would require monitoring with an oxygen sensor. Instead, diesel engines rely on other emission control systems, such as diesel particulate filters (DPFs) and selective catalytic reduction (SCR), to reduce harmful emissions and meet emission standards.