Patent ID: 11946425
Assignee: HITACHI ASTEMO, LTD.
Field: Engines, pumps, turbines (Mechanical engineering)
Classification: CPC F  G  Y | IPC F  G

Claim 0:
1. An engine control device comprising:
a crank angle sensor that outputs a crank signal including an angular position signal for every predetermined angle and a reference position signal for every crank angle of 360°, with rotation of a crank shaft;
a cam angle sensor that outputs cam signals at different levels between a front reference position and a rear reference position of the crank signals, with rotation of a cam shaft; and
an electronic control unit configured to determine an expected value according to a changed state of the cam signal, and to distinguish among cylinders with the use of the cam signal when a value of the cam signal is equal to the expected value, and to distinguish among the cylinders by the use of the expected value when a value of the cam signal is different from the expected value, wherein
when a cam position has become a front-rear determination position specified by counting of the crank signals, a cam signal read value is set according to the cam signal, an abnormality counter is updated, and a cam signal selection value is selected according to a changed state of the cam signal read value;
when the cam position has become the cylinder distinguishing position specified by counting of the crank signals, a cylinder distinguishing value is set according to the cam signal selection value;
when the cam signal read value has changed, the abnormality counter is reset and a value of the cam signal read value is updated to match a value of the expected value; and
when the cam signal read value has not changed, the abnormality counter is updated, and the expected value is updated to match a value corresponding to an inverted value of the expected value at a previous measurement time;

wherein
the cam signal read value is a measure of the rotation of the cam shaft;
the expected value is a stored value of the expected rotation of the cam shaft; and
the abnormality counter counts the number of occasions that the cam signal read value has consecutively caused abnormality.