Method for controlling the temperature of an emission control device
First Claim
1. A method for operating an engine having a first and second group of cylinders, wherein said engine further comprises a throttle, comprising:
- operating in a first mode wherein the first cylinder group operates with air and substantially no injected fuel and the second cylinder group operates by combusting air and injected fuel at a lean air-fuel ratio, and during said first mode, said air for said first and second group of cylinders gasses through said throttle;
providing an indication of the device temperature; and
in response to said indication, disabling said first mode of operation and operating the engine in a second mode of operation.
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Accused Products
Abstract
A method is disclosed for controlling operation of an engine coupled to an exhaust treatment catalyst. Under predetermined conditions, the method operates an engine with a first group of cylinders combusting a lean air/fuel mixture and a second group of cylinders pumping air only (i.e., without fuel injection). In addition, the engine control method also provides the following features in combination with the above-described split air/lean mode: idle speed control, sensor diagnostics, air/fuel ratio control, adaptive learning, fuel vapor purging, catalyst temperature estimation, default operation, and exhaust gas and emission control device temperature control. In addition, the engine control method also changes to combusting in all cylinders under preselected operating conditions such as fuel vapor purging, manifold vacuum control, and purging of stored oxidants in an emission control device.
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Citations
12 Claims
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1. A method for operating an engine having a first and second group of cylinders, wherein said engine further comprises a throttle, comprising:
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operating in a first mode wherein the first cylinder group operates with air and substantially no injected fuel and the second cylinder group operates by combusting air and injected fuel at a lean air-fuel ratio, and during said first mode, said air for said first and second group of cylinders gasses through said throttle; providing an indication of the device temperature; and in response to said indication, disabling said first mode of operation and operating the engine in a second mode of operation. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for operating an engine having a first and second group of cylinders, comprising:
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in response to a desired engine output torque determined based on operating conditions, operating in a first mode wherein the first cylinder group operates with air and substantially no injected fuel and the second cylinder group operates by combusting air and injected fuel at a lean air-fuel ratio; providing an indication of whether the device temperature is within a preselected temperature range; and in response to said indication, disabling said first mode of operation and operating the engine in a second mode of operation including retarding ignition timing of cylinders in the second group.
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8. A method for operating an engine having a first and second group of cylinders, wherein said engine further comprises a throttle, comprising:
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in response to a desired engine output torque determined based on operating conditions, operating in a first mode wherein the first cylinder group operates with air and substantially no injected fuel and the second cylinder group operates by combusting air and injected fuel at a lean air-fuel ratio, and during said first mode, said air for said first and second group of cylinders passes through said throttle; providing an indication of whether the device temperature is within a preselected temperature range; and in response to said indication, disabling said first mode of operation and operating the engine in a second mode of operation including injecting fuel in said first group. - View Dependent Claims (9, 10, 11, 12)
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Specification