Method and apparatus for estimating an atmospheric pressure based on an intact air pressure at a certain time

Claim 1

An apparatus for controlling an internal combustion engine of a motor vehicle, comprising: means for sensing an intake air pressure in an intake passage of said engine; means for sensing a rotational speed of said engine; means for sensing a load of said engine; control means for: (1) discriminating operating conditions of said engine in response to the sensed rotational speed and the sensed load, and producing a discrimination output when a first condition and a second condition simultaneously exist, said first condition existing when the sensed rotational speed is below a predetermined speed and said second condition existing when the sensed load is above a predetermined load; (2) determining the sensed intake air pressure when said discrimination output is produced, as an estimate of an actual atmospheric pressure; and (3) determining a control amount for said engine in accordance with the sensed intake air pressure, the sensed rotational speed and the estimated atmospheric pressure while said engine is operating.

Claim 2

An apparatus for controlling an internal combustion engine of a motor vehicle, comprising: means for sensing an intake air pressure in an intake passage of said engine; means for sensing a rotational speed of said engine; means for sensing a load of said engine; control means for: (1) discriminating operating conditions of said engine in response to the sensed rotational speed and the sensed load, and producing a discrimination output when a first condition and a second condition simultaneously exist, said first condition existing when the sensed rotational speed is below a predetermined speed and said second condition existing when the sensed load is above a predetermined load; (2) determining the sensed intake air pressure when said discrimination output is produced, as an estimate of an actual atmospheric pressure; and (3) determining a control amount for said engine in accordance with the sensed intake air pressure, the sensed rotational speed and the estimated atmospheric pressure while said engine is operating.

Claim 7

An apparatus for controlling an internal combustion engine of a motor vehicle comprising: first means, responsive to an intake air pressure in an intake passage of said engine, for producing a first output indicative of the intake air pressure; and control means for: (1) discriminating load conditions of said engine and producing a second output indicative of a heavy load condition in which the intake air pressure is close to an atmospheric pressure; (2) obtaining an estimate of atmospheric pressure from said first output each time said second output is produced and producing a third output indicative of said estimated atmospheric pressure; (3) storing said third output indicative of the estimated atmospheric pressure, and updating the stored third output each time said atmospheric pressure is estimated; and (4) determining a control amount for said engine in accordance with operating conditions of said engine including at least the stored third output indicative of the simulated intake air pressure.

Claim 8

An apparatus for controlling an internal combustion engine of a motor vehicle comprising: first means, responsive to an intake air pressure in an intake passage of said engine, for producing a first output indicative of the intake air pressure; and control means for: (1) discriminating load conditions of said engine and producing a second output indicative of a heavy load condition in which the intake air pressure is close to an atmospheric pressure; (2) obtaining an estimate of atmospheric pressure from said first output each time said second output is produced and producing a third output indicative of said estimated atmospheric pressure; (3) storing said third output indicative of the estimated atmospheric pressure, and updating the stored third output each time said atmospheric pressure is estimated; and (4) determining a control amount for said engine in accordance with operating conditions of said engine including at least the stored third output indicative of the simulated intake air pressure.

Claim 9

An apparatus for controlling an internal combustion engine of a motor vehicle which operates when a key switch of said motor vehicle is turned on, comprising: a pressure sensor for sensing an intake air pressure in an intake passage of said engine; a speed sensor for sensing a rotational speed of said engine; a load sensor for sensing a load of said engine; a fuel injector provided on said engine for injecting, when activated, fuel into said engine; a spark plug provided on said engine for igniting, when activated, the injected fuel; and programmed computer means, operative when said key switch of said motor vehicle is turned on, for controlling activations of at least one of said fuel injector and said spark plug, said programmed computer for: (1) storing, responsive to a change in position of said key position to a turning on condition from a turn-off condition, the intake air pressure sensed by said pressure sensor immediately after the turning-on of said key switch as a first atmospheric pressure; (2) discriminating whether the rotational speed sensed by said speed sensor is below a predetermined speed reference and producing an output indicative of a low speed condition; (3) discriminating whether the load sensed by said load sensor is above a predetermined load reference and producing an output indicative of a high load condition; (4) correcting, by a predetermined correction value, the intake air pressure sensed by said pressure sensor when the low speed and high load are both produced and storing the corrected intake air pressure as a second atmospheric pressure; and (5) determining a control amount for at least one of said fuel injector and said spark plug in accordance with the sensed rotational speed, the sensed intake air pressure and the stored atmospheric pressure, and using said first atmospheric pressure until the second atmospheric pressure is stored and using the second atmospheric pressure thereafter.

Claim 10

An apparatus for controlling an internal combustion engine of a motor vehicle which operates when a key switch of said motor vehicle is turned on, comprising: a pressure sensor for sensing an intake air pressure in an intake passage of said engine; a speed sensor for sensing a rotational speed of said engine; a load sensor for sensing a load of said engine; a fuel injector provided on said engine for injecting, when activated, fuel into said engine; a spark plug provided on said engine for igniting, when activated, the injected fuel; and programmed computer means, operative when said key switch of said motor vehicle is turned on, for controlling activations of at least one of said fuel injector and said spark plug, said programmed computer for: (1) storing, responsive to a change in position of said key position to a turning on condition from a turn-off condition, the intake air pressure sensed by said pressure sensor immediately after the turning-on of said key switch as a first atmospheric pressure; (2) discriminating whether the rotational speed sensed by said speed sensor is below a predetermined speed reference and producing an output indicative of a low speed condition; (3) discriminating whether the load sensed by said load sensor is above a predetermined load reference and producing an output indicative of a high load condition; (4) correcting, by a predetermined correction value, the intake air pressure sensed by said pressure sensor when the low speed and high load are both produced and storing the corrected intake air pressure as a second atmospheric pressure; and (5) determining a control amount for at least one of said fuel injector and said spark plug in accordance with the sensed rotational speed, the sensed intake air pressure and the stored atmospheric pressure, and using said first atmospheric pressure until the second atmospheric pressure is stored and using the second atmospheric pressure thereafter.

Claim 11

A method for controlling an internal combustion engine of a motor vehicle, comprising the steps of: sensing an intake air pressure in an intake passage of said engine; sensing a rotational speed of said engine; sensing a load of said engine; discriminating operating conditions of said engine in response to the sensed rotational speed and the sensed load; producing a discrimination output when both the sensed rotational speed is below a predetermined speed and sensed load is above a predetermined load; using the sensed intake air pressure as an estimate of actual atmospheric pressure when said discrimination output is produced; and determining a control amount for said engine in accordance with the sensed intake air pressure, the sensed rotational speed and the estimated atmospheric pressure.

Claim 12

A method for controlling an internal combustion engine of a motor vehicle, comprising the steps of: sensing an intake air pressure in an intake passage of said engine; sensing a rotational speed of said engine; sensing a load of said engine; discriminating operating conditions of said engine in response to the sensed rotational speed and the sensed load; producing a discrimination output when both the sensed rotational speed is below a predetermined speed and sensed load is above a predetermined load; using the sensed intake air pressure as an estimate of actual atmospheric pressure when said discrimination output is produced; and determining a control amount for said engine in accordance with the sensed intake air pressure, the sensed rotational speed and the estimated atmospheric pressure.

Claim 17

A method for controlling an internal combustion engine of a motor vehicle, comprising the steps of: sensing an intake air pressure in an intake passage of said engine; producing a first output indicative of the sensed intake air pressure; discriminating load conditions of said engine; producing a second output indicative of a heavy load condition in which the sensed intake air pressure is close to an atmosphere pressure; estimating an atmospheric pressure based on said first output at a time of producing said second output; producing a third output indicative of the estimated atmospheric pressure; storing said third output in a storage location of a memory; updating the stored third output each time the atmospheric pressure is newly estimated; and determining a control amount for said engine in accordance with at least the stored third output.

Claim 18

A method for controlling an internal combustion engine of a motor vehicle, comprising the steps of: sensing an intake air pressure in an intake passage of said engine; producing a first output indicative of the sensed intake air pressure; discriminating load conditions of said engine; producing a second output indicative of a heavy load condition in which the sensed intake air pressure is close to an atmosphere pressure; estimating an atmospheric pressure based on said first output at a time of producing said second output; producing a third output indicative of the estimated atmospheric pressure; storing said third output in a storage location of a memory; updating the stored third output each time the atmospheric pressure is newly estimated; and determining a control amount for said engine in accordance with at least the stored third output.

Claim 19

A method for controlling an internal combustion engine of a motor vehicle, comprising the steps of: sensing an intake air pressure in an intake passage of said engine; sensing a rotational speed of said engine; sensing a load of said engine; storing the sensed intake air pressure at a time immediately after a turning-on of a key switch of said vehicle in a memory of a control unit provided on said vehicle as a first atmospheric pressure; discriminating whether the sensed rotational speed is below a predetermined speed reference; producing a first output signal when the sensed rotational speed is below said speed reference; discriminating whether the sensed load is above a predetermined load reference; producing a second output signal when the sensed load is above said load reference; correcting, by a predetermined correction value, the sensed intake air pressure when said first and second output signals are both produced; storing the corrected intake air pressure in said memory as a second atmospheric pressure; and determining at least one of a fuel injection amount and an ignition timing for a spark plug which are both provided on said engine, in accordance with the sensed rotational speed, the sensed intake air pressure, and at least one of said first and second atmospheric pressures.

Claim 20

A method for controlling an internal combustion engine of a motor vehicle, comprising the steps of: sensing an intake air pressure in an intake passage of said engine; sensing a rotational speed of said engine; sensing a load of said engine; storing the sensed intake air pressure at a time immediately after a turning-on of a key switch of said vehicle in a memory of a control unit provided on said vehicle as a first atmospheric pressure; discriminating whether the sensed rotational speed is below a predetermined speed reference; producing a first output signal when the sensed rotational speed is below said speed reference; discriminating whether the sensed load is above a predetermined load reference; producing a second output signal when the sensed load is above said load reference; correcting, by a predetermined correction value, the sensed intake air pressure when said first and second output signals are both produced; storing the corrected intake air pressure in said memory as a second atmospheric pressure; and determining at least one of a fuel injection amount and an ignition timing for a spark plug which are both provided on said engine, in accordance with the sensed rotational speed, the sensed intake air pressure, and at least one of said first and second atmospheric pressures.