Device for determining the abnormal degree of deterioration of a catalyst
First Claim
1. A device for determining the abnormal degree of deterioration of catalyst of a catalytic converter arranged in an internal combustion engine exhaust system, comprising:
- first purification ability grasping means for grasping a first purification ability of said catalyst in complete activation condition of said catalyst;
second purification ability grasping means for grasping a second purification ability of said catalyst in incomplete activation condition of said catalyst;
overall purification ability calculating means for calculating an overall purification ability of said catalyst such that said first purification ability given a first weight is added to said second purification ability given a second weight which is less than said first weight; and
abnormality determining means for determining if the degree of deterioration of said catalyst is abnormal by the comparison between said overall purification ability and a predetermined threshold thereof.
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Abstract
A device for determining the abnormal degree of deterioration of a catalyst of a catalytic converter arranged in an internal combustion engine exhaust system is disclosed. The device includes first and second air-fuel ratio sensors located upstream and downstream of the catalyst. The device determines a first purification ability based on readings of the sensors during a warmup stage of the catalyst, and a second purification ability after the warmup is completed. An overall purification ability of the catalyst is determined by combining the purification ability of the catalyst during warmup and the purification ability of the catalyst after warmup, where the weight of the purification ability during warmup is less than the purification ability after warmup in the overall purification ability. If the overall purification ability of the catalyst is less than a certain amount, then the device determines that the catalyst has deteriorated.
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Citations
5 Claims
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1. A device for determining the abnormal degree of deterioration of catalyst of a catalytic converter arranged in an internal combustion engine exhaust system, comprising:
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first purification ability grasping means for grasping a first purification ability of said catalyst in complete activation condition of said catalyst; second purification ability grasping means for grasping a second purification ability of said catalyst in incomplete activation condition of said catalyst; overall purification ability calculating means for calculating an overall purification ability of said catalyst such that said first purification ability given a first weight is added to said second purification ability given a second weight which is less than said first weight; and abnormality determining means for determining if the degree of deterioration of said catalyst is abnormal by the comparison between said overall purification ability and a predetermined threshold thereof. - View Dependent Claims (2, 3, 4, 5)
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Specification