Method for improving engine starting
First Claim
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1. An engine starting method, comprising:
- providing a constant air mass to an engine after engine run-up until a predetermined condition, the constant air mass provided at a first altitude and a second altitude, a desired amount of vacuum provided by the engine at the first altitude, an additional amount of vacuum than the desired amount of vacuum provided by the engine at the second altitude, the second altitude lower than the first altitude;
adjusting ignition timing to provide a torque to achieve a desired engine idle speed while the engine inducts the constant air mass; and
advancing spark timing toward minimum spark advance timing for best engine torque (MBT) timing in response to an increase in engine torque while the engine inducts the constant air mass.
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Abstract
A method for improving exhaust after treatment initial warm up during engine starting is presented. In one example, the method adjusts an engine air flow amount to a level where a desired substantially constant heat flux is provided by the engine to an exhaust after treatment device. The method may reduce fuel consumption and a need for a vacuum pump to provide vacuum to vacuum consumers of a vehicle during exhaust after treatment heating.
33 Citations
19 Claims
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1. An engine starting method, comprising:
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providing a constant air mass to an engine after engine run-up until a predetermined condition, the constant air mass provided at a first altitude and a second altitude, a desired amount of vacuum provided by the engine at the first altitude, an additional amount of vacuum than the desired amount of vacuum provided by the engine at the second altitude, the second altitude lower than the first altitude; adjusting ignition timing to provide a torque to achieve a desired engine idle speed while the engine inducts the constant air mass; and advancing spark timing toward minimum spark advance timing for best engine torque (MBT) timing in response to an increase in engine torque while the engine inducts the constant air mass. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An engine starting method, comprising:
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inducting air to an engine at a constant flow rate after engine start; adjusting ignition timing to provide a desired engine speed while inducting air to the engine at the constant flow rate; advancing spark until providing minimum spark advance timing for best engine torque (MBT) timing in response to an increasing engine load while the engine inducts air at the constant flow rate, then increasing engine air flow to meet the increasing engine load while holding spark timing at MBT timing after spark timing is advanced to MBT timing in response to the increasing engine load; and providing an indication of engine heating greater than a desired amount in response to heat flux provided by the engine greater than a threshold amount, and reducing the constant flow rate in response to a fuel type varying from an expected fuel type. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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14. A system for starting an engine coupled to a transmission, comprising:
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an engine; an exhaust after treatment device coupled to the engine; and a controller including executable instructions stored in non-transitory memory to provide a constant air mass flow rate at a first altitude and a second altitude, a desired amount of vacuum provided by the engine at the first altitude, an additional amount of vacuum than the desired amount of vacuum provided at the second altitude, the second altitude lower than the first altitude. - View Dependent Claims (15, 16, 17, 18, 19)
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Specification