Control apparatus for internal combustion engine

摘要

An object of this invention is to accurately detect a sensitivity abnormality of an in-cylinder pressure sensor over a wide operating range without using other sensor outputs or the like. Based on only the output of an in-cylinder pressure sensor 44, an ECU 50 acquires a first parameter that is affected by an output sensitivity of the sensor, and a second parameter that is not affected by the output sensitivity. Specifically, the ECU 50 acquires a heat release quantity PVκ as the first parameter, and acquires an indicated torque ratio (A2/A1) as a second parameter. The ECU 50 also calculates a determination coefficient α that is a ratio between the first and second parameters, and determines that the output sensitivity of the in-cylinder pressure sensor 44 is abnormal when the determination coefficient α deviates from an allowable range. Thus, even without utilizing another sensor output or the like in an auxiliary manner or previously preparing a large amount of data or the like, a sensitivity abnormality of the in-cylinder pressure sensor 44 can be easily detected over a wide operating range.

主权项

1. A control apparatus for an internal combustion engine, comprising:
an in-cylinder pressure sensor configured to output a signal corresponding to an in-cylinder pressure of the internal combustion engine; and an electronic control unit programmed to; acquire a first parameter which is acquired based on the output of the in-cylinder pressure sensor and which is affected by an output sensitivity of the sensor; acquire a second parameter which has a correlation with the first parameter and which is not affected by the output sensitivity, and calculate two indicators based on in-cylinder pressures obtained at different crank angles in an identical cycle and calculate the second parameter based on a ratio between the indicators; determine whether or not an abnormality of the output sensitivity of the in-cylinder pressure sensor exists based on a relationship between the first parameter and the second parameter; and control at least one of a throttle valve, a fuel injection valve, or a spark plug based upon a result of the abnormality determination.