Patent ID: 7499789

Claim:
A deterioration signal generation device for a gas sensor for simulating a deterioration signal output by a gas sensor in a deteriorated state, the gas sensor detecting the fuel-air ratio of exhaust gas from an internal combustion engine based on the concentration of particular components in the exhaust gas, the deterioration signal generation device comprising: a reference signal acquisition unit which is connected to a reference sensor identical in configuration to the gas sensor for outputting a reference signal for generating the deterioration signal, the reference signal being associated with the concentration of the particular component in the exhaust gas, and which acquires the reference signal at constant time intervals; a reference signal storing unit for storing the reference signals acquired by the reference signal acquisition unit in the order of acquisition; a delay time setting unit for setting a delay time for outputting the reference signal while delaying the starting point of a change in the signal as a result of a change in a target fuel-air ratio of a mixture supplied to the internal combustion engine; and a signal delay generation unit for generating the reference signal stored in the reference signal storing unit at a time preceding the current opportunity for acquisition a number of times corresponding to the delay time set by the delay time setting unit.