It also helps the engine’s overall efficiency. This final stage allows the engine to supply the cat with enough oxygen to complete the oxidization process effectively with the second catalyst. At this point, all the fuel entering the combustion chamber uses all the available oxygen to complete the combustion process. The onboard computer then adjusts the fuel/air ratio, allowing the engine to run close to the Stoichiometric point. The last stage of emission control involves the sensor relaying back to the ECU the amount of oxygen within the exhaust gasses. These catalysts burn or oxidize the hydrocarbons and carbon monoxide present within the incoming gas to minimize the amonut of smog generated by evaporated, unburnt fuel.
Each metal has a specific task in emission reduction. Within the cat housing, there’s a ceramic-based honeycomb structure lined with precious metals. The cat changes the chemical nature of exhaust gases to minimize the volume of harmful emissions from the exhaust manifold. Truck owners checked the fuel mix through hands-on mechanical observation or by examining the spark plugs. New computerized fuel systems have replaced older traditional fuel systems where a carburetor provided an air and fuel mix. The cat is tied into a computerized engine system with oxygen sensors that monitor the fuel mix of your car to protect the air you breathe.