Exhaust System: Description and Operation

This model has a header pipe, three-way catalytic converter, and warm-up converter.
The principal parts that comprise the engine exhaust system are the warm-up catalytic converter, the pipe and catalytic converter assembly, the muffler, and the tail pipe. Each component is joined with a gasket to prevent exhaust leaks. The system is secured to the frame with four rubber supports.

The engine exhaust gases consist mainly of nitrogen (N2). However, they also contain carbon monoxide (CO), carbon dioxide (C02), water vapor (HERO), oxygen (02), nitrogen oxides (NOx), and hydrogen (H2) as well as various other unburned hydrocarbons (HC). Three of these exhaust gases, CO, NOx, and HO are major air pollutants and must be controlled.

The warm-up catalytic converter is positioned as far upstream in the exhaust flow as possible to take advantage of the high exhaust temperature in the manifold. The operating temperature of the warm-up catalytic converter increases very rapidly after initial cold start to decrease the amount of emissions emitted during cold engine operation.

Header pipe and three-way catalytic converter is welded into one unit The three-way catalytic converter reacts with exhaust gases to convert them to less harmful products and therefore reduce the pollutant levels to within legally prescribed limits.

The catalytic metals are thinly coated onto a honeycomb-shaped, high temperature ceramic. The honeycomb is mounted inside the converter shell which is surrounded by a heat shield. This design produces little restriction to the flow of exhaust gases and has proven to be durable.

CAUTION: Do not touch the catalytic converter heat shield when the engine is running. The conversion process produces high heat. Even when the engine is not running, it remains hot a long time. It will remain hot after other pipes have cooled. Touching the heat shield may produce a serious burn.