How the exhaust system works
Date:2022.02.15 Views:1374
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Exhaust system refers to the system that collects and discharges exhaust gas, including exhaust manifold, exhaust pipe, muffler pipe, tail pipe and resonator.
Due to the stringent environmental regulations on vehicle pollution, no matter idling, acceleration, low-speed driving, high-speed driving, or deceleration, they must meet the pollution standards. In the face of such strict restrictions, in addition to achieving a balance between performance and pollution Besides, the only "skip" is the catalytic converter. Catalytic converters usually use precious metals as raw materials, including oxidation catalysts, reduction catalysts and three-way catalytic converters used in most vehicles.
After the exhaust manifold, a catalytic converter is connected to convert incompletely combusted pollutants into harmless substances to protect the environment.
Let's take a simple chemistry class again. The HC and CO in the sewage are produced by incomplete combustion. To eliminate them, they must be burned again, that is, to oxidize them, so this is the task of the oxidation catalyst. The formation of NOx is caused by the oxidation of nitrogen, so a reducing catalyst is necessary to reduce NOx to nitrogen. The three-way catalytic converter allows the oxidation of HC and CO and the reduction of NOx to occur in the same catalyst. The catalyst itself participates in the oxidation or reduction chemical reaction process, but it is generated in the front of the reaction process; the overall amount does not change, and the substance in the catalytic converter is the catalyst in the chemical reaction.
Where is the catalytic converter located? The early catalytic converters were mostly installed in the middle of the exhaust pipe, and most of them were installed immediately after the exhaust manifold, so that the catalyst could reach the working temperature quickly. The catalyst must be at a high temperature close to 500 degrees to obtain better conversion efficiency, and at low temperature, there is almost no conversion capacity, so the amount of pollutants discharged from cold cars is quite large. Therefore, I would like to remind all car owners not to warm up the car in the indoor or underground parking lot, and try to drive the car outdoors as soon as it starts, so as not to poison themselves or other people in the parking lot.
