Atmospheric pressure detecting method for controlling internal combustion engine and apparatus therefor

An atmospheric pressure detecting method for controlling an internal combustion engine, which is a method of detecting atmospheric pressure as a control condition when controlling a fuel injection quantity from an injector for supplying fuel to the internal combustion engine, comprising the steps of:

• providing intake pipe pressure detection means for sampling intake pipe pressure at a downstream side from a throttle valve of said internal combustion engine at predetermined sampling intervals and detecting it as absolute pressure;
• obtaining an absolute value of a difference between a maximum value and a minimum value of the intake pipe pressure, which is sampled while said internal combustion engine performs one combustion cycle, as an intake pipe pressure change quantity;
• taking the maximum value of the intake pipe pressure as a basic detection value when the intake pipe pressure change quantity is equal to or less than a set value;
• and
• taking a value, which is obtained by correcting the basic detection value by a correction amount determined in accordance with rotational speed of the internal combustion engine, as a detection value of atmospheric pressure.

An atmospheric pressure detecting method for controlling an internal combustion engine, which is a method of detecting atmospheric pressure as a control condition when controlling a fuel injection quantity from an injector for supplying fuel to a single cylinder internal combustion engine or a multi-cylinder internal combustion engine provided with an intake pipe and a throttle valve at each cylinder, comprising the steps of:

• providing intake pipe pressure detection means for sampling output of an intake pressure sensor, which is provided to detect intake pipe pressure at a downstream side from a throttle valve in the intake pipe provided for one cylinder of said internal combustion engine, at predetermined sampling intervals and detecting the intake pipe pressure as absolute pressure;
• performing, for n cycle or n cycles of combustion of said internal combustion engine (n represents an integer of 1 or more),:
• a maximum/minimum detection process for detecting a maximum value and a minimum value of the intake pipe pressure detected while said internal combustion engine performs one combustion cycle, an intake pipe pressure change quantity detection process for obtaining an absolute value of a difference between the maximum value and the minimum value detected in the maximum/minimum value detection process as an intake pipe pressure change quantity, and an atmospheric pressure detection condition determining process for comparing an obtained intake pressure change quantity with a previously determined set value each time the intake pipe pressure change quantity is obtained in the intake pipe pressure change quantity detection process and determining that the atmospheric pressure detection condition is satisfied when the intake pipe pressure change quantity is equal to or less than the set value;
• and
• taking the maximum value of the intake pipe pressure detected in the maximum/minimum value detection process as a detection value of atmospheric pressure when it is determined that the atmospheric detection condition is satisfied in all the n time or n times of atmospheric pressure detection condition determining process performed for n cycle or n cycles of combustion.

An atmospheric pressure detecting method for controlling an internal combustion engine, which is a method of detecting atmospheric pressure as a control condition when controlling a fuel injection quantity from an injector for supplying fuel to a single cylinder internal combustion engine or a multi-cylinder internal combustion engine provided with an intake pipe and a throttle valve at each cylinder, comprising the steps of:

• providing intake pipe pressure detection means for sampling output of an intake pressure sensor, which is provided to detect intake pipe pressure at a downstream side from a throttle valve in the intake pipe provided for one cylinder of said internal combustion engine, at predetermined sampling intervals and detecting the intake pipe pressure as absolute pressure;
• performing, for n cycle or n cycles of combustion of said internal combustion engine (n represents an integer of 1 or more),:
• a maximum/minimum detection process for detecting a maximum value and a minimum value of the intake pipe pressure detected while said internal combustion engine performs one combustion cycle, an intake pipe pressure change quantity detection process for obtaining an absolute value of a difference between the maximum value and the minimum value detected in the maximum/minimum value detection process as an intake pipe pressure change quantity, and an atmospheric pressure detection condition determining process for comparing an obtained intake pressure change quantity with a previously determined set value each time the intake pipe pressure change quantity is obtained in the intake pipe pressure change quantity detection process and determining that the atmospheric pressure detection condition is satisfied when the intake pipe pressure change quantity is equal to or less than the set value;
• and
• taking the maximum value of the intake pipe pressure detected in the maximum/minimum value detection process as a basic detection value of atmospheric pressure when it is determined that the atmospheric detection condition is satisfied in all the n time or n times of atmospheric pressure detection condition determining process performed for n cycle or n cycles of combustion, and taking a value, which is obtained by correcting the basic detection value by a correction amount determined according to a rotational speed of said internal combustion engine, as a detection value of atmospheric pressure.

An atmospheric pressure detecting apparatus for controlling an internal combustion engine, which is for detecting atmospheric pressure as a control condition when controlling a fuel injection quantity from an injector for supplying fuel to a single cylinder internal combustion engine or a multi-cylinder internal combustion engine provided with an intake pipe and a throttle valve at each cylinder, comprising:

• intake pipe pressure detection means for sampling output of an intake pressure sensor, which is provided to detect intake pipe pressure at a downstream side from a throttle valve in the intake pipe provided for one cylinder of said internal combustion engine, at predetermined sampling intervals and detecting the intake pipe pressure as absolute pressure;
• maximum/minimum value detection means for detecting a maximum value and a minimum value of the intake pipe pressure detected while said internal combustion engine performs one combustion cycle;
• intake pipe pressure change quantity detection means for obtaining an absolute value of a difference between the maximum value and the minimum value detected by said maximum/minimum value detection means as an intake pipe pressure change quantity;
• atmospheric pressure detection condition determining means for comparing an obtained intake pressure change quantity with a previously determined set value each time said intake pipe pressure change quantity detection means obtains the intake pipe pressure change quantity and determining that the atmospheric pressure detection condition is satisfied when the intake pipe pressure change quantity is equal to or less than the set value;
• and
• atmospheric pressure detection value determining means for determining the maximum value of the intake pipe pressure detected in the maximum/minimum value detection process as a detection value of atmospheric pressure when it is determined by said atmospheric pressure detection condition determining means that the atmospheric detection condition is satisfied in all the cycles of combustion while said internal combustion engine performs n cycle or n cycles of combustion (n represents an integer of 1 or more) and making a storage device store the detection value of atmospheric pressure.

An atmospheric pressure detecting apparatus for controlling an internal combustion engine, which is for detecting atmospheric pressure as a control condition when controlling a fuel injection quantity from an injector for supplying fuel to a single cylinder internal combustion engine or a multi-cylinder internal combustion engine provided with an intake pipe and a throttle valve at each cylinder, comprising:

• intake pipe pressure detection means for sampling output of an intake pressure sensor, which is provided to detect intake pipe pressure at a downstream side from the throttle valve in the intake pipe provided for one cylinder of said internal combustion engine, at predetermined sampling intervals and detecting the intake pipe pressure as absolute pressure;
• maximum/minimum value detection means for detecting a maximum value and a minimum value of the intake pipe pressure detected while said internal combustion engine performs one combustion cycle;
• intake pipe pressure change quantity detection means for obtaining an absolute value of a difference between the maximum value and the minimum value detected by said maximum/minimum value detection means as an intake pipe pressure change quantity;
• atmospheric pressure detection condition determining means for comparing an obtained intake pressure change quantity with a previously determined set value each time said intake pipe pressure change quantity detection means obtains the intake pipe pressure change quantity and determining that the atmospheric pressure detection condition is satisfied when the intake pipe pressure change quantity is equal to or less than the set value;
• atmospheric pressure basic detection value determining means for determining the maximum value of the intake pipe pressure detected in the maximum/minimum value detection process as a basic detection value of atmospheric pressure when it is determined by said atmospheric pressure detection condition determining means that the atmospheric detection condition is satisfied in all the cycles of combustion while said internal combustion engine performs n cycle or n cycles of combustion (n represents an integer of 1 or more) and making a storage device store the basic detection value;
• rotational speed detection means for detecting rotational speed of said internal combustion engine;
• map storage means for storing a rotational speed/correction value map which gives relationship between the rotational speed of said internal combustion engine and a correction value needed to be added to the basic detection value to obtain the atmospheric pressure;
• correction value operation means for arithmetically operating a correction value from the rotational speed/correction value map in accordance with the rotational speed of the internal combustion engine detected by said rotational speed detection means;
• and
• atmospheric pressure detection value operation means for obtaining the detection value of atmospheric pressure by adding said correction value to said basic detection value.