| 摘要 |
In a non-critical pressure region where a pressure ratio [Pm/Pthrup(i-1)] of an intake air pressure Pm(throttle downstream pressure) detected by an intake air pressure sensor to a previous throttle upstream pressure Pthrup(i-1) is greater than a predetermined value B, the previous throttle upstream pressure Pthrup(i-1) is substituted for one of two terms of the throttle upstream pressures Pthrup(i) included in an intake system model so that present throttle upstream pressure Pthrup(i) is calculated. In a critical pressure region where the pressure ratio is less than or equal to the predetermined value B, a physical value f(Pm/Pthrup(i)) using a pressure ratio [Pm/Pthrup(i)] of the intake air pressure Pm to a present throttle upstream pressure Pthrup(i) as a parameter is regarded as a steady value fc so that the present throttle upstream pressure Pthrup(i) is calculated.
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