Methods and system for operating an engine
First Claim
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1. An engine operating method, comprising:
- generating a vacuum request;
generating a catalyst heating request; and
combusting air and fuel within a cylinder of an engine at a retarded spark timing, wherein the retarded spark timing is selected based on the generated vacuum request and the generated catalyst heating request, wherein combusting air and fuel at the retarded spark timing provides engine torque insufficient to rotate the engine at an idle speed, while rotating the engine at the idle speed via torque produced by a motor in response to the generated catalyst heating request.
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Abstract
Systems and methods for increasing engine vacuum production and catalyst heating of a hybrid powertrain are described. In one example, a motor/generator rotates an engine at idle speed while the engine combusts air and fuel without providing torque sufficient to rotate the engine so that spark timing may be advanced or retarded from minimum spark timing for best torque to heat a catalyst and generate vacuum for vacuum consumers.
34 Citations
20 Claims
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1. An engine operating method, comprising:
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generating a vacuum request; generating a catalyst heating request; and combusting air and fuel within a cylinder of an engine at a retarded spark timing, wherein the retarded spark timing is selected based on the generated vacuum request and the generated catalyst heating request, wherein combusting air and fuel at the retarded spark timing provides engine torque insufficient to rotate the engine at an idle speed, while rotating the engine at the idle speed via torque produced by a motor in response to the generated catalyst heating request. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. An engine operating method, comprising:
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generating a vacuum request; generating a catalyst heating request; supplying spark to cylinders of an engine at a timing advanced or retarded from minimum spark for best torque spark timing, wherein the timing advanced or retarded from minimum spark for best torque spark timing is selected based on both the generated vacuum request and the generated catalyst heating request, the timing advanced or retarded from minimum spark for best torque spark timing adjusted based on a difference in desired vacuum and actual vacuum; and combusting air and fuel within a cylinder of the engine at the timing advanced or retarded from minimum spark for best torque spark timing producing insufficient engine torque to rotate the engine at a desired idle speed while compensating for the insufficient engine torque with torque produced by a motor to rotate the engine at the desired idle speed in response to the generated vacuum request and the generated catalyst heating request. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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15. A system, comprising:
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an engine; a transmission coupled to the engine; a motor/generator coupled to the engine via a belt; and a vehicle system controller including executable instructions stored in non-transitory memory to generate a vacuum request and a catalyst heating request, rotate the engine at an idle speed via the motor/generator while the engine is combusting air and fuel in response to the generated vacuum request and the catalyst heating request, the engine producing torque that is insufficient to rotate the engine at the idle speed, wherein a torque of the motor/generator increases based on the generated catalyst heating request, wherein the idle speed is based on both the generated vacuum request and the catalyst heating request. - View Dependent Claims (16, 17, 18, 19, 20)
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Specification