Method and system for controlling engine fueling

Abstract

The disclosure provides a method and system for controlling engine fueling. Methods and systems are provided for tracking a fuel puddle mass in the intake port of a deactivated engine cylinder. The difference in fuel evaporation rate in the deactivated cylinder intake is accounted for by applying distinct time constant and gain values to a transient fuel compensation model. A fuel vapor content isclipped once the intake vapor pressure in the intake port of the deactivated cylinder reaches a saturation pressure limit.

Description

technical field [0001] The present description generally relates to methods and systems for controlling fueling of engine cylinders to compensate for fueling dynamics. Background technique [0002] Controlling an internal combustion engine to maintain a desired air-fuel ratio (AFR) in the combustion chamber reduces emissions. For example, fuel is delivered via electronically controlled fuel injectors that may be coupled inside each engine cylinder or located in the cylinder's intake port. However, not all injected fuel enters the combustion chamber. Instead, some fuel gets stored in the engine's intake manifold, causing a phenomenon commonly known as "wall wetting." For example, in engines configured with port fuel injection, fuel is injected into the intake port aft of the closed intake valve during the non-intake stroke of the cylinder. The injected fuel evaporates quickly due to heat from the valves and mixes with the intake air, then the air-fuel mixture is introduced...

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Problems solved by technology

Thereafter, vapor pressure buildup can be limited

As another example, any disturbance in manifold pressure can cause vapors to escape into the engine's intake manifold and cause additional AFR fluctuations

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