Adaptive transient fuel compensation for a spark ignited engine

A method of adaptive transient fuel compensation for a cylinder in a multi-cylinder engine comprising the steps of:

• estimating a first wall-wetting parameter indicative of a fraction of an amount of fuel injected that is retained on surfaces of an intake system for the cylinder of the multi-cylinder engine in accordance with the following relationship:
• ##EQU21## estimating a second wall-wetting parameter indicative of a fraction of an amount of fuel vaporized from the surfaces in the intake system for the cylinder of the multi-cylinder engine in accordance with the following relationship:
• ##EQU22## where:
• k is an engine cycle index
• u is a filtered value of fuel injected
• y is a filtered value of measured fuel burned
• v is a weighted covariance of exhaust gas sensor measurements
• P.sub.1 is an inverse of a weighted covariance of the estimate of c
• P.sub.2 is an inverse of a weighted covariance of the estimate of b.sub.v
• p(k)=[b.sub.v (k)c(k)]'
• y(k)=y(k)-y(k-1)+u(k-1)-u(k)
• h(k)=[(u(k-1)-y(k-1) (u(k-1)-u(k))];
• and
• adjusting fuel delivery to the cylinder of the multi-cylinder engine dependent on the estimated first and second wall-wetting parameters.

A method of adaptive transient fuel compensation for a cylinder in a multi-cylinder engine comprising the steps of:

• estimating a first wall-wetting parameter indicative of a fraction of an amount of fuel injected that is retained on surfaces of an intake system for the cylinder of the multi-cylinder engine;
• estimating a second wall-wetting parameter indicative of a fraction of an amount of fuel vaporized from the surfaces in the intake system for the cylinder of the multi-cylinder engine;
• and
• adjusting fuel delivery using a lead compensator with adjustable zero and pole tuning while the estimate of the first wall-wetting parameter is small and a wall-wetting dynamics zero identified dependent on the first and second wall-wetting parameters is invertible.

A method of adaptive transient fuel compensation for a cylinder in a multi-cylinder engine comprising the steps of:

• estimating a first wall-wetting parameter indicative of a fraction of an amount of fuel injected that is retained on surfaces of an intake system for the cylinder of the multi-cylinder engine;
• estimating a second wall-wetting parameter indicative of a fraction of an amount of fuel vaporized from the surfaces in the intake system for the cylinder of the multi-cylinder engine;
• and
• adjusting fuel delivery using a lead compensator with adjustable zero tuning and a fixed pole while the estimate of the first wall-wetting parameter is large, and adjusting fuel delivery using a lead compensator with adjustable zero tuning and a fixed pole while a wall-wetting dynamics zero, identified dependent on the first and second wall-wetting parameters, is not invertible.

A method of adaptive transient fuel compensation for a cylinder in a multi-cylinder engine comprising the steps of:

• measuring an air charge ingested by the cylinder of the multi-cylinder engine and providing an air mass variable dependent thereon;
• determining and filtering a value of fuel injected for the cylinder of the multi-cylinder engine and providing a fuel mass injected variable dependent thereon;
• measuring an exhaust fuel/air ratio in an exhaust system and providing an exhaust fuel/air ratio variable dependent thereon;
• combining the air mass variable and the exhaust fuel/air ratio variable and providing a measure of fuel burned;
• filtering the measure of fuel burned and providing a filtered fuel mass burned variable dependent thereon;
• estimating fuel puddle dynamics for the cylinder of the multi-cylinder engine by determining parameters of a wall-wetting dynamic model on an engine cycle-by-cycle basis dependent on the fuel mass injected variable, and the filtered fuel mass burned variable;
• and
• adjusting fuel delivery for the cylinder of the multi-cylinder engine dependent-on the estimated fuel puddle dynamics.