Misfire Detection Phase Compensation for Engine Torsion
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Solution Overview
Problem
The existing misfire detection apparatus for internal combustion engines experiences a decrease in detection accuracy due to phase shifts between crankshaft and downstream-side speeds, particularly exacerbated by communication delays and varying rotation speeds, which complicates the calculation of torsion speed components.
Innovation Solution
The apparatus incorporates a phase compensation process that adjusts the phase difference between crankshaft and downstream-side speeds using a variable phase compensation amount based on the rotation speed of the crankshaft, and incorporates interpolation to reduce phase differences, ensuring accurate calculation of torsion speed components by delaying the acquisition time of downstream-side speeds relative to crankshaft speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If downstream-side speed is acquired at predetermined time intervals, then the acquisition process is simplified and execution is convenient, but a phase shift occurs between the instantaneous rotation speed of the crankshaft and the downstream-side speed, decreasing misfire detection accuracy
Solution Approach 1:
The patent applies preliminary action by acquiring the downstream-side speed in advance at predetermined time intervals before it is needed for calculation. The acquired speed data is stored and then used after applying phase compensation based on the crankshaft rotation angle. This allows the system to maintain the convenience of time-based acquisition while correcting the phase shift that would otherwise degrade accuracy.
2Productivity
If crank-side speed is acquired at every predetermined rotation angle and downstream-side speed is acquired at every predetermined time, then the acquisition methods differ in timing, but this creates a phase shift that decreases the calculation accuracy of the torsion speed component
Solution Approach 1:
The patent applies parameter changes by dynamically adjusting the phase compensation amount based on the crankshaft rotation angle and rotation speed. The phase compensation parameter is calculated to align the downstream-side speed with the crank-side speed in time, thereby eliminating the phase shift that would otherwise reduce calculation accuracy of the torsion speed component.
3Adaptability or versatility
If the rotation speed of the crankshaft varies, then the operating conditions change, but the average phase shift magnitude varies with rotation speed, requiring adaptive compensation
Solution Approach 1:
The patent applies dynamics by making the phase compensation amount variable rather than fixed. The phase compensation is dynamically adjusted based on the current crankshaft rotation angle and rotation speed. This allows the system to adapt to varying operating conditions while maintaining accurate alignment between the crank-side and downstream-side speeds across different rotation speeds.
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
This configuration enhances the accuracy of misfire detection by compensating for phase shifts and communication delays, maintaining high accuracy even at varying rotation speeds, thereby improving the reliability of misfire detection.
Implementation Method 1
a torsion speed component based on a physical model of which an input is a difference between the crank-side speed and the downstream-side speed, the torsion speed component being a component due to torsion of the damper in the crank-side speed
Data Source
AI summary
A CPU substitutes a difference between a crank-side speed that is a rotation speed of a crankshaft and a downstream-side speed that is a speed of a portion, opposite from the crankshaft, in a damper into a differential speed. The CPU calculates a torsion speed component that is a speed component of the crankshaft due to torsion of the damper based on a physical model of which an input is the differential speed, and calculates a time that is a variable indicating a speed of the crankshaft, used to determine a misfire, based on the torsion speed component. The CPU delays acquisition time of the downstream-side speed used to calculate the differential speed, with respect to acquisition time of the crank-side speed according to the rotation speed of the crankshaft.