Gas Engine Ignition Timing Control for Rapid Knock Optimization
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Solution Overview
Problem
In gas engine systems, when load varies significantly, the slow advancement of ignition timing due to a preset advance rate leads to inefficient operation and prolonged optimization time, especially when the delay calculation value of the knocking occurrence ratio falls below the target occurrence ratio.
Innovation Solution
A gas engine system that includes a controller to calculate a delay calculation value of a knocking occurrence ratio, determine primary and secondary target ignition timings based on occurrence ratio differences, and rapidly advance the ignition timing by a second advance rate if specific conditions are met, while preventing frequent or unallowable knocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ignition timing is advanced slowly based on a preset advance rate, then stable operation is realized, but the time required for ignition timing optimization becomes long
Solution Approach 1:
The patent applies dynamics by making the advance rate variable rather than fixed. The controller dynamically adjusts the advance rate based on the difference between the delay calculation value and target occurrence ratio: using a first advance rate when the difference is small and a second (higher) advance rate when the difference is large. This allows the system to adapt its behavior based on current operating conditions, resolving the contradiction between stability and optimization speed.
Solution Approach 2:
The patent changes the parameter of advance rate from a constant preset value to a variable value that depends on the occurrence ratio difference. By introducing this parameter change, the system can achieve both stable operation (when differences are small) and rapid optimization (when differences are large), thereby resolving the technical contradiction.
2Loss of time
If the ignition timing is advanced rapidly to reduce optimization time, then the time required for optimization is reduced, but frequent or unallowable knocking may occur
Solution Approach 1:
The patent implements feedback by continuously monitoring the delay calculation value of the knocking occurrence ratio and using this information to adjust the advance rate. The controller compares the delay calculation value with the target occurrence ratio and adjusts the ignition timing accordingly. This feedback mechanism ensures that rapid advancement only occurs when necessary and safe, preventing frequent or unallowable knocking while reducing optimization time.
Solution Approach 2:
The patent applies dynamics by making the advance rate variable based on real-time conditions. The controller uses a first advance rate under normal conditions and switches to a second (higher) advance rate only when the occurrence ratio difference is large, thereby reducing optimization time when needed while maintaining stability and preventing knocking under normal operating conditions.
Data Source
AI summary
A gas engine system controller: calculates a delay calculation value of a knocking occurrence ratio; determines a primary target ignition timing; sets the primary target ignition timing as a current ignition timing if the occurrence ratio difference is positive and an ignition timing does not exceed a converted value of a first advance rate; determines whether a rapid advance condition is satisfied if the occurrence ratio difference is positive and the ignition timing difference exceeds the converted value of the first advance rate; sets a secondary target ignition timing as the current ignition timing if the rapid advance condition is not satisfied, the secondary target ignition timing obtained by adding the converted value of the first advance rate to the previous ignition timing; and determines the current ignition timing so as to achieve a second advance rate greater than the first advance rate if the rapid advance condition is satisfied.