Cylinder Intake Air Calculation Using Feedback Correction
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Solution Overview
Problem
Existing methods for calculating the cylinder intake air amount in internal combustion engines suffer from prediction errors, leading to inaccuracies in air-fuel ratio control, especially in transient operating conditions.
Innovation Solution
A cylinder intake air amount calculating apparatus that uses an intake pipe model equation, incorporating intake air flow rate and preceding cylinder intake air amount, to calculate both the current and predicted intake air amounts, with updates to volumetric efficiency to improve accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the predicted value of cylinder intake air amount is calculated using the preceding predicted value, then the calculation can be simplified, but the prediction accuracy deteriorates due to accumulation of prediction errors
Solution Approach 1:
The patent applies feedback by using the actually detected intake air flow rate to correct the predicted cylinder intake air amount. The correction amount is calculated based on the difference between the predicted intake air flow rate and the actually detected intake air flow rate, thereby eliminating accumulated prediction errors and improving accuracy without increasing calculation complexity
Solution Approach 2:
The patent changes the parameter used for prediction correction from the preceding predicted value to the actually detected intake air flow rate. This parameter change allows the system to use real measurement data to correct predictions, thereby improving accuracy while maintaining the simplicity of the calculation method
2Ease of operation
If the predicted cylinder intake air amount is calculated using the preceding predicted value, then the calculation process is simplified, but the air-fuel ratio control accuracy deteriorates in transient conditions
Solution Approach 1:
The patent introduces feedback correction using the actually detected intake air flow rate to improve air-fuel ratio control accuracy during transient conditions. The correction amount is added to the predicted cylinder intake air amount, ensuring accurate fuel injection control even when engine operating conditions change rapidly
Solution Approach 2:
The patent performs preliminary calculation of the predicted cylinder intake air amount using the simplified method, then applies correction based on actual measurements. This two-stage approach maintains calculation ease while ensuring control accuracy through preliminary prediction followed by corrective adjustment
Data Source
AI summary
A cylinder intake air amount calculating apparatus for an internal combustion engine that calculates a cylinder intake air amount, which is an amount of fresh air sucked in a cylinder of the engine using an intake air pipe model equation which is obtained by modeling an intake pipe of the engine, is provided. An intake air flow rate is obtained. The cylinder intake air amount is calculated by applying the intake air flow rate and a preceding value of the cylinder intake air amount to the intake pipe model equation. A predicted intake air flow rate which is a predicted value of the intake air flow rate is calculated. A predicted cylinder intake air amount which is a predicted value of the cylinder intake air amount is calculated by applying the predicted intake air flow rate and the cylinder intake air amount to the intake pipe model equation.