Software air-flow meter for an internal combustion engine

Claim 2

An engine - controller combination, comprising: a vehicle engine; means for determining measures of a set of engine parameters and for providing measurement signals indicative of said measures; and a microprocessor control unit, including (i) means for receiving the measurement signals, (ii) means for determining a prediction set including at least one predicted value of a measurable engine parameter and at least one predicted value of mass airflow into the engine, (iii) means for determining an estimation set including at least one estimated value of mass airflow into the engine, and (iv) means for controlling the engine in response to the estimated value of mass airflow, wherein the microprocessor control unit iteratively (i) determines the prediction set in response to (a) the measurement signals, (b) a linear model comprising a set of fixed predetermined model parameters, and (c) the estimation set, and (ii) determines the estimation set in response to (a) a present measure of the measurable engine parameter, (b) the prediction set, and (c) a correction set of fixed predetermined correction coefficients wherein the estimated value of the mass airflow into the engine is a substantially accurate measure of actual mass airflow into the engine.

Claim 3

The combination of claim 1, wherein the measurable engine parameter is manifold absolute pressure.

Claim 4

The combination of claim 1, wherein the controlling means controls fueling of the engine by developing a fuel command in response to the estimated mass airflow and outputting the fuel command to a fuel injection control unit, which fuels the engine in response to the fuel command, thereby improving engine air-fuel ratio control.

Claim 5

The combination of claim 3, wherein the measurable engine parameter is manifold, absolute pressure.

Claim 6

The combination of claim 1, wherein the controlling means controls engine spark through spark timing and dwell commands output to a spark timing control module, by developing the spark timing and dwell commands in response to the prediction set and outputting the spark timing and dwell commands to the spark timing control module.

Claim 7

The combination of claim 5, wherein the measurable engine parameter is manifold absolute pressure.

Claim 8

The combination of claim 1, wherein the controlling means controls an idle air control valve through an idle air control valve command, by developing the idle air control valve command in response to the prediction set and outputting the idle air control valve command to the idle air control valve.

Claim 9

The combination of claim 7, wherein the measurable engine parameter is manifold absolute pressure.

Claim 10

The combination of claim 1, wherein: the prediction set of a given engine event comprises a vector X p (k+1) where k is a present engine event, the measures of the set of engine parameters comprise a vector U(k), the estimation set comprises a vector X e (k), and the set of fixed predetermined model parameters comprises matrices A, B, and C, the prediction set being determined by a relation: X.sup.P (k+1)=AX.sup.e (k)+BU(k)+C; and the correction set comprises a vector G, and X p (k) and X(k) represent predicted and measured values of the measurable engine parameter at event k, respectively, the estimation set being determined by a relation: X.sup.e (k)=X.sup.p (k)+G(X(k)-X.sup.p (k)).

Claim 11

The combination of claim 9, wherein the measurable engine parameter is manifold absolute pressure.

Claim 12

The combination of claim 10, wherein the set of model parameters is predetermined through statistical regression.

Claim 13

The combination of claim 10, wherein the set of model parameters is scheduled according to two independent engine parameters.

Claim 14

The combination of claim 10, wherein the correction set is predetermined through Kalman filtering.

Claim 15

The combination of claim 1, wherein the correction set is predetermined through Kalman filtering.

Claim 16

The combination of claim 1, wherein the set of engine parameters includes throttle position and engine speed.

Claim 17

The combination of claim 10, wherein the set of engine parameters includes throttle position and engine speed.

Claim 18

The combination of claim 15, wherein the set of engine parameters also includes at least one member of a set comprising: manifold absolute pressure, idle air control valve position, exhaust gas recirculation valve position, atmospheric pressure and air temperature.

Claim 19

The combination of claim 16, wherein the set of engine parameters also includes at least one member of a set comprising: manifold absolute pressure, idle air control valve position, exhaust gas recirculation valve position, atmospheric pressure and air temperature.

Claim 20

An engine - controller combination, comprising: a vehicle engine; means for determining measures of a set of engine parameters and for providing measurement signals indicative of said measures for every event k; and a microprocessor control unit, including (i) means for receiving the measurement signals, (ii) means for determining a prediction set including at least one predicted value of a measurable engine parameter and at least one predicted value of mass airflow into the engine, (iii) means for determining an estimation set including at least one estimated value of mass airflow into the engine, and (iv) means for controlling the engine in response to the estimated value of mass airflow, wherein the microprocessor control unit: initializes a set of variables including the measures of the set of engine parameters and the estimation set for events preceding time k, and the prediction set for events preceding time k+1; thereafter iteratively: receives the measurement signals for event k; determines an error signal in response to a difference between a measure of the measurable engine state at event k and a prediction of the measurable engine state for event k; schedules a correction set of fixed predetermined correction coefficients in response to two of the measurement signals representing independent engine parameters; determines the estimation set in response to the prediction set, the error signal, and the correction set; schedules a set of fixed model parameters in response to the two measurement signals representing independent engine parameters; determines the prediction set in response to the measurement signals for event k and preceding events, the estimation set, the set of fixed model parameters; determines a control command in response to the estimated mass airflow; and applies the control command to the engine.

Claim 21

An engine - controller combination, comprising: a vehicle engine; means for determining measures of a set of engine parameters and for providing measurement signals indicative of said measures for every event k; and a microprocessor control unit, including (i) means for receiving the measurement signals, (ii) means for determining a prediction set including at least one predicted value of a measurable engine parameter and at least one predicted value of mass airflow into the engine, (iii) means for determining an estimation set including at least one estimated value of mass airflow into the engine, and (iv) means for controlling the engine in response to the estimated value of mass airflow, wherein the microprocessor control unit: initializes a set of variables including the measures of the set of engine parameters and the estimation set for events preceding time k, and the prediction set for events preceding time k+1; thereafter iteratively: receives the measurement signals for event k; determines an error signal in response to a difference between a measure of the measurable engine state at event k and a prediction of the measurable engine state for event k; schedules a correction set of fixed predetermined correction coefficients in response to two of the measurement signals representing independent engine parameters; determines the estimation set in response to the prediction set, the error signal, and the correction set; schedules a set of fixed model parameters in response to the two measurement signals representing independent engine parameters; determines the prediction set in response to the measurement signals for event k and preceding events, the estimation set, the set of fixed model parameters; determines a control command in response to the estimated mass airflow; and applies the control command to the engine.

Claim 22

The combination of claim 19, wherein the measurable engine parameter is manifold absolute pressure.

Claim 23

The combination of claim 19, wherein the set of model parameters and the correction set are scheduled from control unit memory.

Claim 24

The combination of claim 19, wherein the set of engine parameters includes throttle position and engine speed.

Claim 25

The combination of claim 20, wherein the set of engine parameters includes throttle position and engine speed.

Claim 26

The combination of claim 22, wherein the set of engine parameters also includes at least one member of a set comprising: manifold absolute pressure, idle air control valve position, exhaust gas recirculation valve position, atmospheric pressure and air temperature.

Claim 27

The combination of claim 23, wherein the set of engine parameters also includes at least one member of a set comprising: manifold absolute pressure, idle air control valve position, exhaust gas recirculation valve position, atmospheric pressure and air temperature.