| 摘要 |
A heat-ray type of airflow meter (14) has a signal processor (14a) for converting a detected air quantity into a frequency signal. An engine controller (10) has a conversion table (10a) for converting the frequency signal into an air quantity. The signal processor (14a) and the conversion table (10a) have features such that the frequency increases in correspondence with increases in the magnitude of a positive air quantity, and the frequency decreases in correspondence with increases in the absolute value of a negative air quantity. In the conversion table (10a), a prescribed positive air quantity value (Qa1) is assigned as a dummy output for frequencies lower than a prescribed threshold value (Frsh). Under normal circumstances, frequencies lower than a minimum value (Frmin) are not used. The frequency decreases to near 0 Hz when there is a disconnection or a short circuit, the dummy output (Qa1) is therefore output, and an injection quantity equal to or greater than a misfire limit is ensured. |
