Engine Control Method and System
AssigneeFord Global Technologies, LLC
InventorsMichael Daniel Shane, James David Pakko, Paul M. Laing
Life of this patent
Estimating the term…
Abstract
Methods and systems are provided for heating a catalyst during engine cold-start conditions. One example embodiment uses positive valve overlap to drive a boosted blow-through airflow through the cylinders of an engine. Fuel is injected with the blow-through airflow during the valve overlap, and also injected into engine cylinders outside the valve overlap. The catalyst is heated by the resulting exothermic reaction of the blow-through airflow with the combustion products and the injected fuel in the exhaust manifold.
Claims20
A method of operating a boosted engine, comprising,
- during an engine cold start,
- operating the engine with positive intake to exhaust valve overlap to drive a boosted blow-through airflow into an engine exhaust through engine cylinders;
- injecting a first amount of fuel during the valve overlap;
- injecting a second amount of fuel outside of the valve overlap;
- and
- exothermically reacting the blow-through airflow with fuel in the exhaust.
A method of operating an engine, comprising:
- during a first engine cold-start condition, mixing a rich blow-through air-fuel mixture with a lean cylinder combustion air-fuel mixture in an exhaust manifold to generate more heat at an exhaust catalyst;
- and
- during a second engine cold-start condition, mixing a lean blow-through air-fuel mixture with a rich cylinder combustion air-fuel mixture in the exhaust manifold to generate less heat at the exhaust catalyst.
An engine system, comprising:
- a boosted engine;
- a direct injector for direct injecting fuel into an engine cylinder;
- an exhaust catalyst;
- an exhaust gas oxygen sensor;
- and
- a control system including instructions for:
- injecting a first amount of fuel and driving an amount of boosted air through engine cylinders into an exhaust manifold, during a positive intake to exhaust valve overlap period, to generate a blow-through mixture;
- injecting a second amount of fuel after the valve overlap but before the intake valve closes to generate a cylinder combustion mixture;
- and
- exothermically reacting the blow-through mixture with the cylinder combustion mixture in the exhaust manifold.
Dependencies are inferred from the claim text.