Why does the car's exhaust pipe turn red?

[DanielLynn]

Car exhaust pipes turning red occur because some of the fuel mixture from the cylinders continues to burn inside the exhaust pipe. If the air-fuel mixture is too lean, the combustion speed of the flammable gas slows down, extending into the exhaust stroke and causing the exhaust pipe to turn red. Below are the specific reasons: 1. Burning gases rushing into the exhaust pipe raise the exhaust temperature. This can happen due to poor sealing of the exhaust valve or excessively small valve clearance, allowing burning gases to enter the exhaust pipe and increase its temperature. Delayed fuel injection not only slows combustion but also leads to incomplete combustion, causing diesel to burn in the exhaust pipe during later stages of injection, further raising the exhaust temperature. 2. During maintenance, adjust the air-fuel mixture concentration, inspect and adjust valve clearance, and fine-tune ignition or injection timing. Remove the exhaust pipe and muffler, disassemble the muffler, and clean carbon deposits by soaking in kerosene (or using chemical methods), scraping with a blade, or burning the muffler core over an open flame to dry it out. Finally, clean with a wire brush. Replace any worn or damaged components as necessary for repair.