Patent ID: 8918268
Filing Date: 2014-12-23
Classification: F02D,Y02T

Abstract:
1. A malfunction detecting device for an internal combustion engine, comprising: an engine which includes plural cylinders and which is capable of switching plural kinds of fuels including a gas fuel and a liquid fuel; a gas pressure sensor provided on a passage or in a pipe for supplying the gas fuel to each of the cylinders; an air-fuel ratio sensor provided on an exhaust passage connected to the engine; an injection quantity estimation unit configured to estimate, when there is a request to switch from an operation by the gas fuel to an operation by the liquid fuel and the air-fuel ratio sensor is not activated, an injection quantity of each of the cylinders at a time of the operation by the gas fuel based on a decreasing degree of gas pressure detected by the gas pressure sensor; a malfunction detection unit configured to detect a malfunction with respect to an imbalance of air fuel ratios among the cylinders based on the injection quantity of each of the cylinders estimated by the injection quantity estimation unit; and a switching unit configured to switch from the operation by the gas fuel to the operation by the liquid fuel after detecting the malfunction by the malfunction detection unit.