Device for purifying exhaust gas of engine
First Claim
1. A device for purifying the exhaust gas of an engine having an exhaust passage, the device comprising:
- an exhaust gas purifying catalyst arranged in the exhaust passage;
a start catalyst arranged in the exhaust passage upstream of the exhaust gas purifying catalyst;
means for forming a gas including oxygen;
means for forming a gas including a reducing agent;
means for forming at least one of the gas including oxygen and the gas including the reducing agent from the exhaust gas of the engine;
means for mixing the gas including oxygen and the gas including the reducing agent and feeding the gas mixture to the exhaust gas purifying catalyst without the gas mixture flowing into the start catalyst;
judging means for judging whether the exhaust gas purifying catalyst is poisoned, wherein a reactivation of the exhaust gas purifying catalyst is performed when the exhaust gas is judged to be poisoned; and
means for obtaining a cumulative fuel amount of the fuel fed to the engine during the usual engine operation, wherein the exhaust gas purifying catalyst is judged to be poisoned when the cumulative fuel amount is larger than a predetermined amount.
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Accused Products
Abstract
An engine has a plurality of the cylinders. The cylinders are divided into a first cylinder group and a second cylinder group, and each cylinder group is connected, via a corresponding branch exhaust passage, to a common interconnecting exhaust passage. In the interconnecting exhaust passage, an exhaust gas purifying catalyst is arranged. The air-fuel ratio of the exhaust gas of the first cylinder group is made lean to feed oxygen to the exhaust gas purifying catalyst, and the air-fuel ratio of the second cylinder group is made rich to feed fuel for heating to the exhaust gas purifying catalyst, so that the oxygen and the fuel for heating react with each other to heat the exhaust gas purifying catalyst to reactivate the exhaust gas purifying catalyst when the reactivation of the exhaust gas purifying catalyst is must be performed. In each branch exhaust passage, a start catalyst is arranged.
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Citations
28 Claims
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1. A device for purifying the exhaust gas of an engine having an exhaust passage, the device comprising:
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an exhaust gas purifying catalyst arranged in the exhaust passage; a start catalyst arranged in the exhaust passage upstream of the exhaust gas purifying catalyst; means for forming a gas including oxygen; means for forming a gas including a reducing agent; means for forming at least one of the gas including oxygen and the gas including the reducing agent from the exhaust gas of the engine; means for mixing the gas including oxygen and the gas including the reducing agent and feeding the gas mixture to the exhaust gas purifying catalyst without the gas mixture flowing into the start catalyst; judging means for judging whether the exhaust gas purifying catalyst is poisoned, wherein a reactivation of the exhaust gas purifying catalyst is performed when the exhaust gas is judged to be poisoned; and means for obtaining a cumulative fuel amount of the fuel fed to the engine during the usual engine operation, wherein the exhaust gas purifying catalyst is judged to be poisoned when the cumulative fuel amount is larger than a predetermined amount. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26)
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27. A device for purifying the exhaust gas of an engine having an exhaust passage, the device comprising:
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an exhaust gas purifying catalyst arranged in the exhaust passage; a start catalyst arranged in the exhaust passage upstream of the exhaust gas purifying catalyst; means for forming a gas including oxygen; means for forming a gas including a reducing agent; means for forming at least one of the gas including oxygen and the gas including the reducing agent from the exhaust gas of the engine; and means for mixing the gas including oxygen and the gas including the reducing agent disposed upstream of the start catalyst and feeding the gas mixture to the exhaust gas purifying catalyst without the gas mixture flowing into the start catalyst.
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28. A device for purifying the exhaust gas of an engine having an exhaust passage, the device comprising:
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an exhaust gas purifying catalyst arranged in the exhaust passage; a start catalyst arranged in the exhaust passage upstream of the exhaust gas purifying catalyst; means for forming a gas including oxygen; means for forming a gas including a reducing agent; means for forming at least one of the gas including oxygen and the gas including the reducing agent from the exhaust gas of the engine; and means for mixing the gas including oxygen and the gas including the reducing agent and feeding the gas mixture to the exhaust gas purifying catalyst without the gas mixture flowing into the start catalyst; wherein the engine has a plurality of cylinders, the cylinders being divided into a plurality of cylinder groups, wherein the air-fuel ratio of the exhaust gas of a part of the cylinder groups is made lean to form the gas including oxygen, and the air-fuel ratio of the exhaust gas of at least one of the remaining cylinder groups is made rich to form the gas including the reducing agent, and each cylinder has a fuel injector directly injecting fuel into the cylinder, and wherein the fuel injector of the at least one of the remaining cylinder groups injects fuel secondarily at the combustion stroke or the exhaust stroke of the engine to form the gas including the reducing agent.
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Specification