EGR SYSTEM

• Main Authors: YOSHIOKA MAMORU, KAWAI SHINJI
• Format: Patent
• Language: English; Japanese
• Published: 13.09.2023
• Subjects: BLASTING; COMBUSTION ENGINES; HEATING; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS; LIGHTING; MECHANICAL ENGINEERING; SUPPLYING COMBUSTION ENGINES IN GENERAL, WITH COMBUSTIBLEMIXTURES OR CONSTITUENTS THEREOF; WEAPONS

To diagnose the presence or absence of at least one abnormality of a bypass valve and a temperature switch at a low cost by employing one temperature switch.SOLUTION: An EGR system comprises: an EGR passage 12 for making an EGR gas flow; an EGR valve 14 for adjusting a flow rate of the EGR gas; an EGR cooler 13 for cooling the EGR gas; a bypass passage 16 bypassing the EGR cooler 13; a bypass valve 17 for opening and closing the bypass passage 16; a temperature SW 78 arranged at a downstream side rather than a merging part 20 of the EGR gas flowing out of the EGR cooler 13 and the EGR gas flowing out of the bypass passage 16; and an electronic control device (ECU) 80. When an engine 1 is brought into a prescribed operation state, and the EGR valve 14 for making the EGR gas flow to the EGR passage 12 is brought into a valve-opened state, the ECU 80 diagnoses at least one abnormality of the bypass valve 17 and the temperature SW 78 on the basis of the presence or absence of at least an output of an on-signal of the temperature SW 78.SELECTED DRAWING: Figure 1 【課題】一つの温度スイッチを採用することにより低コストでバイパス弁及び温度スイッチの少なくとも一方の異常の有無を診断すること。【解決手段】ＥＧＲシステムは、ＥＧＲガスを流すＥＧＲ通路１２、ＥＧＲガスの流量を調節するＥＧＲ弁１４、ＥＧＲガスを冷却するＥＧＲクーラ１３、ＥＧＲクーラ１３を迂回するバイパス通路１６、バイパス通路１６を開閉するバイパス弁１７、ＥＧＲクーラ１３から流れ出るＥＧＲガスとバイパス通路１６から流れ出るＥＧＲガスとの合流部２０より下流に設けられる温度ＳＷ７８及び電子制御装置（ＥＣＵ）８０を備える。ＥＣＵ８０は、エンジン１が所定の運転状態となるときであって、ＥＧＲ通路１２にＥＧＲガスを流すためにＥＧＲ弁１４が開弁状態となるとき、少なくとも温度ＳＷ７８のオン信号の出力の有無に基づき、バイパス弁１７及び温度ＳＷ７８の少なくとも一方の異常を診断する。【選択図】 図１