Engine Knock Control Using Auto-Ignition Timing Prediction
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Solution Overview
Problem
Existing engine systems fail to effectively suppress knocking by determining the degree of knocking occurrence before it happens.
Innovation Solution
An engine control system that estimates auto-ignition delay and predicts auto-ignition timing using in-cylinder pressure, temperature, and fuel gas composition, and adjusts operating conditions to prevent knocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If auto-ignition timing is predicted based on integrated reciprocal of auto-ignition delay, then knocking suppression capability is improved, but calculation complexity increases
Solution Approach 1:
The system performs preliminary estimation of auto-ignition delay at multiple time points during the combustion process, then integrates the reciprocal values to predict auto-ignition timing before knocking occurs. This advance prediction allows the control unit to take preventive action by adjusting injection timing or intake conditions, thereby suppressing knocking while managing calculation complexity through structured computation steps.
2Measurement precision
If multiple parameters including in-cylinder pressure and temperature are measured and estimated, then prediction accuracy is improved, but measurement and processing complexity increases
Solution Approach 1:
The control unit serves multiple functions: it estimates in-cylinder pressure and temperature based on fuel gas composition, calculates auto-ignition delay at multiple time points, integrates reciprocal values to predict auto-ignition timing, and compares this with combustion completion timing. By consolidating these diverse functions into a single control unit that processes multiple parameters simultaneously, the system achieves high prediction accuracy while managing overall system complexity.
3Reliability
If auto-ignition timing is predicted before combustion completion, then knocking can be suppressed, but control timing precision requirements increase
Solution Approach 1:
The system predicts auto-ignition timing by integrating reciprocal auto-ignition delay values before combustion completion occurs. This preliminary prediction provides an advance warning of potential knocking, allowing the control unit to adjust injection timing or intake conditions in advance. The method inherently accounts for the time margin needed to implement control actions, reducing the stringency of real-time control timing precision requirements.
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 system effectively suppresses knocking while maintaining engine efficiency by adjusting intake temperature, pressure, injection amount, and timing based on predicted auto-ignition and combustion completion timings.
Implementation Method 1
a delay estimating unit configured to estimate a auto-ignition delay based on first parameters including a composition of fuel gas
Implementation Method 2
The in-cylinder variable acquiring unit is configured to acquire an in-cylinder pressure and an in-cylinder temperature as the first parameters
Implementation Method 3
The in-cylinder variable acquiring unit preferably may estimate the in-cylinder pressure and the in-cylinder temperature based on a second parameter including the composition of the fuel gas
Implementation Method 4
The completion predicting unit preferably may predict the combustion completion timing based on one of a combustion speed of the fuel gas and the in-cylinder pressure, and an injection amount of the fuel gas
Data Source
Figure 1
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Figure 4A~5
AI summary
Provided is an engine control system 200, including: a delay estimating unit 232 configured to estimate a auto-ignition delay based on first parameters including a composition of fuel gas; a auto-ignition predicting unit 234 configured to predict a auto-ignition timing based on the auto-ignition delay; a completion predicting unit 236 configured to predict a combustion completion timing of the fuel gas; and an operation control unit 238 (control unit) configured to control an engine based on a result of comparison between the auto-ignition timing and the combustion completion timing.