Fault determining apparatus for exhaust passage switching valve
First Claim
1. A fault determining apparatus for determining a fault in an exhaust passage switching valve for switching an exhaust passage of exhaust gases discharged from an internal combustion engine between a first exhaust passage having a three-way catalyst and a second exhaust passage branched off at a location downstream of said three-way catalyst of said first exhaust passage and having filled in an intermediate portion thereof an adsorbent capable of adsorbing hydrocarbons and moisture in the exhaust gases in accordance with an activated state of said three-way catalyst, said fault determining apparatus comprising:
- a humidity sensor arranged at a location downstream of said adsorbent in said second exhaust passage for detecting a humidity of said exhaust gases introduced into said second exhaust passage; and
switching valve fault determining means for determining a fault in said exhaust passage switching valve based on a result of detection performed by said humidity sensor when said exhaust passage should have been switched to said second exhaust passage by said exhaust passage switching valve.
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Accused Products
Abstract
A fault determining apparatus for an exhaust passage switching valve which is capable of directly, rapidly and properly determining a fault in an exhaust passage switching valve, under conditions such as immediately after the start of an internal combustion engine, in which the switching valve should be essentially operated, without the need for setting a special fault determining mode. The fault determining apparatus determines a fault in the exhaust passage switching valve for switching an exhaust passage of exhaust gases discharged from an internal combustion engine between a main exhaust passage having a three-way catalyst and a bypass exhaust passage having filled in an intermediate portion thereof an adsorbent capable of adsorbing hydrocarbons and moisture in the exhaust gases in accordance with an activated state of the three-way catalyst. The fault determining apparatus comprises a humidity sensor for detecting a humidity of the exhaust gases introduced into the bypass exhaust passage, and an ECU for determining a fault in the exhaust passage switching valve based on the result of detection performed by the humidity sensor when the exhaust passage should have been switched to the bypass exhaust passage by the exhaust passage switching valve.
16 Citations
4 Claims
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1. A fault determining apparatus for determining a fault in an exhaust passage switching valve for switching an exhaust passage of exhaust gases discharged from an internal combustion engine between a first exhaust passage having a three-way catalyst and a second exhaust passage branched off at a location downstream of said three-way catalyst of said first exhaust passage and having filled in an intermediate portion thereof an adsorbent capable of adsorbing hydrocarbons and moisture in the exhaust gases in accordance with an activated state of said three-way catalyst, said fault determining apparatus comprising:
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a humidity sensor arranged at a location downstream of said adsorbent in said second exhaust passage for detecting a humidity of said exhaust gases introduced into said second exhaust passage; and
switching valve fault determining means for determining a fault in said exhaust passage switching valve based on a result of detection performed by said humidity sensor when said exhaust passage should have been switched to said second exhaust passage by said exhaust passage switching valve. - View Dependent Claims (2, 3, 4)
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Specification