Engine Ignition Timing Control for Knock Suppression
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Solution Overview
Problem
Conventional engine control methods that retard ignition timing to prevent knocking result in reduced engine torque and fuel efficiency, especially at high compression ratios, where knocking is more likely to occur, leading to increased noise and NOx production.
Innovation Solution
A control device for an engine that performs ignition advance control when knocking occurs at a reference ignition timing set on the retarded side of the MBT in high-load regions, advancing the ignition timing to reduce knocking while maintaining high fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If ignition timing is retarded to prevent knocking, then knocking is suppressed, but engine torque is reduced
Solution Approach 1:
The ignition timing is made dynamically adjustable based on combustion state detection. The control unit detects knocking vibrations and dynamically retards ignition timing only when knocking is detected, rather than using a fixed retarded timing. This allows the engine to operate at optimal ignition timing for maximum torque when knocking is not present, while still preventing knocking when it occurs.
Solution Approach 2:
The system uses feedback from knock detection to control ignition timing. The control unit continuously monitors for knocking vibrations and adjusts ignition timing accordingly, creating a closed-loop control system that balances torque optimization with knocking prevention.
2Object-affected harmful factors
If ignition timing is retarded to prevent knocking, then knocking is suppressed, but fuel efficiency is reduced
Solution Approach 1:
The ignition timing is dynamically adjusted based on real-time combustion state detection. By detecting knocking vibrations and retarding timing only when necessary, the system maintains optimal fuel efficiency during normal operation while preventing knocking when it occurs, rather than permanently operating with retarded timing.
Solution Approach 2:
The feedback mechanism allows the system to maintain optimal fuel efficiency by operating at the best ignition timing when knocking is not detected, while still providing knock protection when needed through dynamic timing adjustment based on sensor feedback.
3Use of energy by moving object
If compression ratio is increased to improve fuel efficiency, then fuel efficiency is improved, but knocking is more likely to occur
Solution Approach 1:
The knock detection and feedback control system enables the engine to safely operate at high compression ratios by dynamically adjusting ignition timing based on detected knocking vibrations. This allows the engine to maintain high compression ratios for improved fuel efficiency while using active knock control to prevent damaging knocking.
Solution Approach 2:
The system changes the ignition timing parameter dynamically in response to detected knocking conditions. By adjusting this critical parameter based on real-time combustion state, the engine can maintain high compression ratios for efficiency while preventing knocking through timely parameter adjustment.
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 approach effectively suppresses knocking, maintains high engine torque, and improves fuel efficiency by ensuring most of the air-fuel mixture burns closer to the compression top dead center, reducing the likelihood of excessive cylinder pressure and noise.
Implementation Method 1
knocking vibrations are generated, thereby causing vibrations of the cylinders and pistons
Implementation Method 2
ignition means for igniting an air-fuel mixture of air and the fuel supplied to the combustion chamber
Implementation Method 3
fuel supply means for supplying fuel containing gasoline to the combustion chamber
Data Source
AI summary
In an engine having fuel supply means for supplying fuel containing gasoline to a combustion chamber and ignition means for igniting an air-fuel mixture, if knocking occurs when ignition is performed at a reference ignition timing set on a retarded side of MBT that is an ignition timing at which the engine torque is maximized in a high-load region in which the engine load is larger than a predetermined load, ignition advance control that causes the ignition means to perform ignition at a timing on an advanced side of the reference ignition timing is performed.