Engine Controller Torque Calculation Error Correction
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Solution Overview
Problem
Conventional methods for measuring cylinder pressure in internal combustion engines face accuracy issues due to modeling errors and high-frequency errors in crank angle measurements, leading to deteriorated estimation of combustion state parameters.
Innovation Solution
A controller and control method that calculates shaft torque in unburning conditions by referencing specific operating condition data, correcting for modeling and manufacturing errors, and canceling high-frequency errors to improve estimation accuracy of combustion state parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the physical model equation of the crank mechanism is used to calculate shaft torque in unburning conditions, then the calculation can be performed in all operating conditions, but modeling errors and manufacturing errors cause inaccuracy in the shaft torque calculation
Solution Approach 1:
The patent performs preliminary measurement and storage of shaft torque in unburning conditions during specific operating conditions (fuel cut) before actual operation. This stored data serves as a reference for correcting calculations in all operating conditions, eliminating the need to perform basic experiments for each engine while achieving high accuracy across the board.
Solution Approach 2:
The patent uses feedback by comparing the physically calculated shaft torque with the actually measured shaft torque in unburning conditions, calculating the difference (error), and then applying this feedback to correct the shaft torque calculations in burning conditions. This closed-loop approach systematically eliminates modeling and manufacturing errors.
2Measurement precision
If basic experiments are performed for each internal combustion engine to measure shaft torque in unburning conditions, then accurate shaft torque data can be obtained, but production efficiency is reduced
Solution Approach 1:
The patent creates a universal solution by measuring shaft torque in unburning conditions once during production for each engine and storing it as reference data. This single measurement serves multiple purposes: it characterizes each individual engine's properties and enables accurate calculations across all operating conditions without requiring repeated experiments, thus maintaining both accuracy and productivity.
3Loss of information
If high frequency error component is not removed from crank angle acceleration, then the original signal information is preserved, but the estimation accuracy of combustion state parameters is deteriorated
Solution Approach 1:
The patent converts the harmful high-frequency error component into a beneficial element by using it as a reference. Since the same high-frequency errors appear in both the physical calculation and actual measurement during unburning conditions, they cancel out when the difference is calculated. This transforms the error from a detriment into a useful reference for eliminating errors in the final combustion state parameter estimation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables accurate calculation of shaft torque in all operating conditions, reducing the impact of modeling and manufacturing errors, and enhances the estimation accuracy of combustion state parameters by canceling high-frequency errors.
Implementation Method 1
an angle information detection unit that detects a crank angle, a crank angle speed, and a crank angle acceleration, based on an output signal of a crank angle sensor
Data Source
AI summary
To provide a controller and a control method for internal combustion engine which can calculate the shaft torque in unburning with good accuracy in all the operating condition in which calculation is required, using the shaft torque in unburning which was set in the specific operating condition, and can improve estimation accuracy of the parameter relevant to the combustion state. A controller for internal combustion engine calculates a specific shaft torque in unburning with reference to a specific unburning condition data; calculates specific and current generated torques of unburning assumption using the physical model equation; calculates a current shaft torque in unburning based on the specific shaft torque in unburning, and the specific and current generated torques of unburning assumption; and calculates an increment of gas pressure torque by burning based on the current shaft torque in unburning and the actual shaft torque in burning condition.