EXHAUST EMISSION PURIFICATION CATALYST TEMPERATURE HOLDING METHOD AND EXHAUST EMISSION PURIFICATION CATALYST TEMPERATURE HOLDING SYSTEM

To provide an exhaust emission purification catalyst temperature holding method for preventing the deterioration of fuel economy, and suppressed in a rise of a cost, and an exhaust emission purification catalyst temperature holding system.SOLUTION: In an exhaust emission purification catalyst temperature holding system 1, at an operation of an internal combustion engine 2, a first selector valve 8 blocks a bypass exhaust passage 6, and makes an upstream-side exhaust passage 5a of the first selector valve 8 and a downstream-side exhaust passage of the first selector valve 8 communicate with each other, and a second selector valve 9 blocks the bypass exhaust passage 6, and makes an upstream-side exhaust passage of the second selector valve 9 and a downstream-side exhaust passage 5c of the second selector valve 9 communicate with each other. At a stop of the internal combustion engine 2, the first selector valve 8 blocks the upstream-side exhaust passage 5a of the first selector valve 8, and makes the downstream-side exhaust passage of the first selector valve 8 and the bypass exhaust passage 6 communicate with each other, and the second selector valve 9 blocks the downstream-side exhaust passage 5c of the second selector valve 9, makes the upstream-side exhaust passage of the second selector valve 9 and the bypass exhaust passage 6 communicate with each other, and drives a motor generator 4.SELECTED DRAWING: Figure 1 【課題】燃費の悪化を防止するとともに、コストの上昇を抑制した排気浄化触媒温度保温方法および排気浄化触媒保温システムを提供する。【解決手段】排気浄化触媒保温システム１は、内燃機関２の稼働時に、第１切換弁８は、バイパス排気通路６を閉塞して、第１切換弁８の上流側排気通路５ａと第１切換弁８の下流側排気通路を連通し、第２切換弁９は、バイパス排気通路６を閉塞して、第２切換弁９の上流側排気通路と第２切換弁９の下流側排気通路５ｃを連通し、内燃機関２の停止時には、第１切換弁８は、第１切換弁８の上流側排気通路５ａを閉塞し、第１切換弁８の下流側の排気通路とバイパス排気通路６を連通し、第２切換弁９は、第２切換弁９の下流側排気通路５ｃを閉塞し、第２切換弁９の上流側排気通路とバイパス排気通路６を連通して、モータ／ジェネレータ４を駆動する。【選択図】図１