Engine Control Device Predicting Speed Peaks to Prevent Vibration
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Solution Overview
Problem
Conventional control devices for internal combustion engines face challenges in predicting engine speed during the idle period, leading to potential vibrations and noise during restart, due to complex calculation processes and accumulated errors in predicting engine speed, which can result in excessive peak values and damage to starter motor components.
Innovation Solution
A control device that detects the focused peak value of engine speed during the back-and-forth phenomenon and uses a decay parameter to predict future extreme values, ensuring the engine speed remains within a predetermined permission range before restarting the engine to avoid excessive peak values and reduce the likelihood of vibrations and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the engine speed is not controlled within a permission range at the beginning of cranking, then the engine can be restarted quickly, but vibration and noise are generated and damage or wear of starter motor components may occur
Solution Approach 1:
The control device predicts the engine speed at the beginning of cranking before actually cranking the engine. Based on this prediction, the control device determines whether the predicted speed falls within a permission range. If not, the cranking timing is adjusted in advance to ensure the engine speed will be within the acceptable range when cranking starts, thereby preventing vibration and noise before they occur.
2Measurement precision
If conventional model formula is used to predict engine speed during idle period, then engine speed prediction can be performed, but calculation process is complicated and errors are accumulated
Solution Approach 1:
Instead of using a complex model formula with multiple variables and integral terms, the invention changes the prediction approach to use a simplified calculation based on the relationship between engine speed and time during the idle period. The control device calculates predicted engine speed by considering the decay characteristics of engine speed during idle, which reduces computational complexity while maintaining sufficient prediction accuracy for determining appropriate cranking timing.
3Object-affected harmful factors
If cranking is delayed to ensure engine speed is within permission range, then vibration and noise are reduced, but engine restart time increases
Solution Approach 1:
The control device performs preliminary prediction of engine speed at the intended cranking moment. This allows the system to determine the optimal cranking timing in advance - if the predicted speed is already within the permission range, cranking can start immediately without delay. The prediction enables precise timing control that avoids unnecessary delays while ensuring vibration and noise are prevented.
Data Source
AI summary
A control device for an engine of the invention executes an automatic stop control for stopping stop a rotation of a crank shaft when a predetermined automatic stop condition is satisfied. The device acquires a focused peak value of the engine speed appearing after a time when a rotation direction of the crank shaft first reverses while the automatic stop control has been executed, determines, based on the focused peak value, whether there will be an excessive peak value expected to depart from a predetermined permission range after the focused peak value appears, and executes a starter start control for driving the starter, restarting the fuel supply and igniting the fuel to restart an operation of the engine when a predetermined restart condition is satisfied, the engine speed is within the predetermined permission range and it has been determined that there will be no excessive peak value.