| 摘要 |
PROBLEM TO BE SOLVED: To diagnose an air flow sensor as being failed, when an excessive stain sticks to a sensor part of the air flow sensor. SOLUTION: When an engine speed Ne and a turbo rotating speed Nt are put in a steady operation state being substantially constant for (t) seconds (S1 and S2), moving averages Ne<SB>AVE</SB>and Nt<SB>AVE</SB>of the engine speed Ne and the turbo rotating speed Nt for (t) seconds are respectively arithmetically operated (S3 and S4). A suction air flow rate Ge corresponding to an engine operation state is estimated and arithmetically operated on the basis of the moving averages Ne<SB>AVE</SB>and Nt<SB>AVE</SB>of the engine speed Ne and the turbo rotating speed Nt (S5). Afterwards, a suction air flow rate Ga measured by the air flow sensor is compensated for the temperature in response to the intake air temperature Ti (S6), and when an absolute value of a difference between the temperature-compensated suction air flow rate Ga and the suction air flow rate Ge is larger than a predetermined value G<SB>0</SB>, it is diagnosed as failure is caused in the air flow sensor (S7 and S8). COPYRIGHT: (C)2007,JPO&INPIT
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