What Causes the Blackening of Civic's Exhaust Pipe?
1 Answers
Civic's exhaust pipe blackening is related to the engine's combustion conditions, such as during warm-up when the engine is cold or under load acceleration. In these scenarios, the system operates in an open-loop control state with relatively prolonged fuel injection timing, leading to the expulsion of partially unburned mixtures. Additional Information: 1. The exhaust pipe is part of the engine's exhaust system, which mainly includes the exhaust manifold, exhaust pipe, and muffler. Typically, the three-way catalytic converter, designed to control engine pollutant emissions, is also installed in the exhaust system. The exhaust pipe generally consists of a front and rear section. Turbocharged engines primarily enhance engine power by increasing intake pressure. The turbocharger operates at extremely high speeds, with its rotation speed dependent on the volume of exhaust gases. The variation in the air-fuel mixture before and after turbo activation is significant, making it inherently more challenging to control the mixture's concentration. Consequently, the likelihood of incomplete fuel combustion is higher in turbocharged models compared to naturally aspirated ones, which is understandable. 2. Part of the unburned oil vapor undergoes carbonization when passing through the three-way catalytic converter. Over time, these carbon deposits accumulate at the exhaust pipe's outlet, resulting in blackening observed in over 80% of turbocharged engine exhaust pipes. Therefore, vehicle owners are advised to regularly maintain their cars, periodically inspect and replace spark plugs, clean the three-way catalytic converter, minimize high-gear low-speed driving, reduce idle time, and frequently clean carbon deposits from various parts of the engine.
