Cylinder-by-cylinder intake air quantity detecting apparatus for internal combustion engine
First Claim
1. A cylinder-by-cylinder intake air quantity detecting apparatus for an internal combustion engine having a plurality of cylinders, the cylinder-by-cylinder intake air quantity detecting apparatus comprising:
- a detecting unit including at least one of an airflow meter for detecting an intake air quantity flowing in an intake pipe, a pressure sensor for detecting pressure in the intake pipe, and an in-cylinder pressure sensor for detecting in-cylinder pressure;
a cylinder-to-cylinder variation learning unit for calculating the rate of cylinder-to-cylinder variations in intake air quantity or the cylinder-by-cylinder intake air quantities based on an output from the detecting unit and for learning the calculated value as a learning value of cylinder-to-cylinder variations in the operating range in which a condition to execute variation learning is met; and
a cylinder-to-cylinder variation estimating unit for estimating the rate of cylinder-to-cylinder variations in intake air quantity or the cylinder-by-cylinder intake air quantities according to a current operating range using the learning value of cylinder-to-cylinder variations in the operating range in which the condition to execute variation learning is not met.
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Accused Products
Abstract
A rate of cylinder-to-cylinder variations in an intake air quantity is calculated, and learned as a learning value based on an output from an airflow meter when a predetermined condition is met. The predetermined condition is set at a preferable condition for learning the rate of cylinder-to-cylinder variations. Subsequently, the rate of cylinder-to-cylinder variations is estimated based on the learning value when the predetermined condition is not met. Thus, cylinder-to-cylinder variations of an engine are accurately obtained in almost all the operating ranges, so that the measurement of the cylinder-by-cylinder intake air quantity with high degree of accuracy is achieved.
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Citations
25 Claims
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1. A cylinder-by-cylinder intake air quantity detecting apparatus for an internal combustion engine having a plurality of cylinders, the cylinder-by-cylinder intake air quantity detecting apparatus comprising:
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a detecting unit including at least one of an airflow meter for detecting an intake air quantity flowing in an intake pipe, a pressure sensor for detecting pressure in the intake pipe, and an in-cylinder pressure sensor for detecting in-cylinder pressure;
a cylinder-to-cylinder variation learning unit for calculating the rate of cylinder-to-cylinder variations in intake air quantity or the cylinder-by-cylinder intake air quantities based on an output from the detecting unit and for learning the calculated value as a learning value of cylinder-to-cylinder variations in the operating range in which a condition to execute variation learning is met; and
a cylinder-to-cylinder variation estimating unit for estimating the rate of cylinder-to-cylinder variations in intake air quantity or the cylinder-by-cylinder intake air quantities according to a current operating range using the learning value of cylinder-to-cylinder variations in the operating range in which the condition to execute variation learning is not met. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 14)
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12. A cylinder-by-cylinder intake air quantity detecting apparatus for an internal combustion engine having a plurality of cylinders, the cylinder-by-cylinder intake air quantity detecting apparatus comprising:
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a detecting unit including at least one of an airflow meter for detecting an intake air quantity flowing in an intake pipe, a pressure sensor for detecting intake pipe pressure in the intake pipe, and an in-cylinder pressure sensor for detecting in-cylinder pressure;
a cylinder-to-cylinder variation learning unit for calculating the rate of cylinder-to-cylinder variations in intake air quantity or the cylinder-by-cylinder intake air quantities and learning the calculated value as a learning value of cylinder-to-cylinder variation based on the output from the detecting unit; and
a unit for prohibiting the variable intake valve mechanism from controlling intake air quantity, during a period in which the learning value of cylinder-to-cylinder variations is learned by the cylinder-to-cylinder variation learning unit, wherein the intake air quantity is controlled by the throttle valve during a period in which the learning value of cylinder-to-cylinder variations is learned by the cylinder-to-cylinder variation learning unit, and the intake air quantity is controlled by the variable intake valve mechanism after completion of leaning of the learning value of cylinder-to-cylinder variations.
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15. A cylinder-by-cylinder intake air quantity detecting apparatus for an internal combustion engine having a plurality of cylinders, the cylinder-by-cylinder intake air quantity detecting apparatus comprising:
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a detecting unit including at least one of an airflow meter for detecting an intake air quantity flowing in an intake pipe, a pressure sensor for detecting intake pipe pressure in the intake pipe, and an in-cylinder pressure sensor for detecting in-cylinder pressure;
an area calculating unit for calculating the area of the intake air quantity of the output waveform from the detecting unit for a predetermined period for one of every intake stroke and every compression stroke of each cylinder;
a cylinder-to-cylinder intake air quantity variations calculating unit for calculating the rate of cylinder-to-cylinder variations in intake air quantity or the cylinder-by-cylinder intake air quantities according to the area of the intake air quantity for the predetermined period of each cylinder. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25)
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Specification