Dynamic Spark Advance Rate for Engine Knock Control
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Solution Overview
Problem
Existing engine knock control systems face challenges in adjusting spark timing advance rate effectively, leading to inefficiencies in engine efficiency and fuel economy, as high advance rates can cause reoccurring engine knock while low rates degrade fuel economy.
Innovation Solution
The method involves judging the presence of knock in an engine cylinder and adjusting the spark advance rate based on the cylinder's previous deactivation mode, such as ceasing fuel flow or maintaining air flow, to optimize spark timing and reduce knock recurrence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a high spark advance rate is used after knock control, then engine fuel economy improves, but engine knock may recur
Solution Approach 1:
The spark advance rate is made dynamic rather than constant. The controller adjusts the spark advance rate based on real-time knock detection and cylinder temperature conditions. When knock is detected, the system retards spark timing and then advances it at a controlled rate that adapts to current engine conditions, allowing the spark advance rate to vary between different operating states to optimize both fuel economy and prevent knock recurrence.
Solution Approach 2:
The system changes the spark timing parameter dynamically in response to knock events. After detecting knock, the controller retards spark timing and then advances it at a controlled rate. The spark advance rate itself is adjusted as a parameter based on cylinder temperature and knock history, transitioning from a constant value to a variable parameter that adapts to changing engine conditions to balance fuel economy and knock prevention.
2Reliability
If a low spark advance rate is used after knock control, then engine knock recurrence is reduced, but engine fuel economy degrades
Solution Approach 1:
The spark advance rate transitions from a static low value to a dynamic value that increases based on engine conditions. After knock control, the system uses a controlled advance rate that adapts to cylinder temperature and knock history, allowing the spark timing to be advanced more aggressively when conditions permit, thereby improving fuel economy while maintaining knock control reliability.
Solution Approach 2:
The spark advance rate parameter is adjusted based on engine operating conditions. The system changes the advance rate from a conservative low value to a variable parameter that increases when knock is suppressed and conditions allow, optimizing the balance between knock control and fuel economy by adapting the parameter to real-time engine state.
3Reliability
If spark timing is retarded to control knock, then engine knock is suppressed, but engine efficiency decreases
Solution Approach 1:
The spark timing control operates in periodic cycles: when knock is detected, spark timing is retarded to suppress knock, then spark timing is advanced at a controlled rate when knock is suppressed. This periodic adjustment between retard and advance creates a control cycle that maintains knock suppression while minimizing efficiency loss by recovering spark timing advancement when conditions permit.
Solution Approach 2:
The system uses knock detection as feedback to control spark timing adjustments. When knock is detected, the controller retards spark timing; when knock is suppressed, the controller advances spark timing at a controlled rate. This feedback mechanism ensures knock suppression while optimizing engine efficiency by advancing spark timing when the feedback indicates knock is not present.
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 improves engine fuel economy and reduces the likelihood of reoccurring engine knock, enhancing vehicle drivability and efficiency.
Implementation Method 1
Air flowing through the cylinders cools the cylinder at a fast rate
Implementation Method 2
combusting air and fuel
Data Source
AI summary
Systems and methods for controlling knock in an internal combustion engine are presented. In one example, spark timing is retarded in engine cylinders where engine knock is indicated and spark is subsequently advanced after it has been retarded. The rate spark timing is advanced may be based on a way engine cylinders have been deactivated.