Adaptive Ignition Timing Control for Engine Knocking Suppression
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Solution Overview
Problem
Existing ignition timing control systems for internal combustion engines face challenges in accurately setting the estimated knocking occurrence ignition timing, particularly in low load regions and when deposits form, leading to inefficient knocking suppression and potential engine damage.
Innovation Solution
The system adjusts the ignition timing by changing the correction amount based on the operating state, using a larger correction when it's difficult to set the estimated knocking occurrence ignition timing, and incorporates a ratio learning process to account for deposit formation, ensuring timely retardation of ignition timing to prevent knocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the learning value learned by learning control is used to set the estimated knocking occurrence ignition timing, then the ignition timing control can be executed efficiently across different operating states, but the accuracy of knocking occurrence timing determination deteriorates in low load regions and when deposits form
Solution Approach 1:
The patent applies dynamics by making the correction amount adaptive rather than fixed. The ECU dynamically adjusts the correction amount based on the operating state (load region and deposit level), transitioning from a static learning value approach to a dynamic correction approach that responds to changing engine conditions, thereby maintaining accuracy across varying operating states
Solution Approach 2:
The patent changes the parameter of correction amount based on operating conditions. By modifying the correction amount according to load region and deposit formation level, the system adapts the ignition timing determination to current engine state, resolving the contradiction between efficient general control and accurate condition-specific control
2Device complexity
If a fixed correction amount is used in feedback correction process, then the control process is simple and fast, but the response to knocking suppression is insufficient when operating state changes to low load region or when deposits form
Solution Approach 1:
The system transitions from a static fixed correction amount to a dynamic variable correction amount that adapts to operating conditions. The ECU determines appropriate correction amounts based on load region and deposit level, making the control process responsive to changing engine states while maintaining relatively simple implementation through pre-established correction tables
3Speed
If the estimated knocking occurrence ignition timing is not accurately set, then the ignition timing can be adjusted quickly, but knocking continues to occur multiple times causing engine damage and occupant discomfort
Solution Approach 1:
The patent applies preliminary action by pre-determining appropriate correction amounts for different operating states (low load region, high deposit level) before actual knocking occurs. The ECU proactively adjusts the correction amount based on current operating conditions, preparing the system to respond effectively when knocking conditions arise, rather than reacting too late
Data Source
AI summary
In an ignition timing control apparatus for an engine, a KCS learning value learned when the engine is in a given operating state is used in an ignition timing control executed when the engine is in the other operating state. An estimated knocking occurrence ignition timing is set based on a most retarded ignition timing using the KCS learning value. A final ignition timing is set by changing a KCS feedback correction value based on whether knocking occurs when ignition is performed at the estimated knocking occurrence ignition timing. When a point indicating the engine operating state moves into a region where it is difficult to set the estimated knocking occurrence ignition timing, the KCS feedback correction value is changed to retard the final ignition timing, and the final ignition timing is set using the KCS learning value and the changed KCS feedback correction value.