Exhaust gas control apparatus for engine and method for producing same

An exhaust gas control apparatus for an engine, comprising:

• a first structure that includes a hydrocarbon-absorbent, which absorbs hydrocarbons present in exhaust gas discharged from an engine;
• a second structure that includes a catalyst, which purifies the exhaust gas discharged from the engine;
• and
• a third structure that changes the flow of the exhaust gas between a first mode, where all of the exhaust gas passes through the hydrocarbon-absorbent, and a second mode, where part of the exhaust gas does not pass through the hydrocarbon-absorbent, wherein
• the first structure, the second structure, and the third structure are independent of each other;
• and the first structure, the second structure, and the third structure are disposed in series, and are joined to each other.

An exhaust gas control apparatus for an engine, comprising:

• a first structure that includes a hydrocarbon-absorbent that absorbs hydrocarbons present in exhaust gas discharged from an engine;
• and
• a second structure that includes a catalyst that purifies the exhaust gas discharged from the engine, wherein the first structure and the second structure are independent of each other;
• and the first structure and the second structure are disposed in series, and are joined to each other.

A method for producing an exhaust gas control apparatus for an engine, which includes a catalyst that purifies exhaust gas discharged from an engine, and a hydrocarbon-absorbent that absorbs hydrocarbon present in the exhaust gas, comprising:

• selecting an absorption portion that achieves a required level of performance from among different absorption portions that achieve different levels of performance, wherein each of the absorption portions includes a first exhaust passage and a second exhaust passage, the respective openings of which are located at different positions, and through which the exhaust gas flows into the absorption portion;
• and the hydrocarbon-absorbent provided in the first exhaust passage;
• selecting a valve portion that achieves a required level of performance from among different valve portions that achieve different levels of performance, wherein each of the valve portions includes a valve that opens and closes the second exhaust passage;
• and each of the valve portions changes a mode where the exhaust gas flows by opening and closing the second exhaust passage using the valve;
• selecting a catalyst portion that achieves a required level of performance from among different catalyst portions that achieve different levels of performance, wherein each of the catalyst portions includes the catalyst;
• and
• disposing, in series, the absorption portion selected in the first step, the valve portion selected in the second step, and the catalyst portion selected in the third step, and joining the absorption portion, the valve portion, and the catalyst portion to each other.