Internal Combustion Engine Knock Detection and Ignition Control
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Solution Overview
Problem
Internal combustion engines experience variations in ignition pressures across piston-cylinder units due to factors like oil deposits, flow conditions, and manufacturing tolerances, leading to inefficient operation and increased nitrogen oxide emissions, as some cylinders run closer to the knocking limit than others.
Innovation Solution
A method that intentionally advances the ignition time in all piston-cylinder units until knocking occurs in those closer to their knock limit, then retards the ignition time in affected units to reduce mechanical stress and emissions, eliminating the need for costly sensor systems by creating an ignition time profile for each cylinder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the ignition time is advanced to operate closer to the knocking limit for higher efficiency, then the efficiency is improved, but the mechanical stress and risk of damage increase
Solution Approach 1:
The patent applies local quality by individualizing the ignition time for each piston-cylinder unit based on its specific knocking behavior. Instead of a uniform ignition time for all cylinders, each cylinder receives a tailored ignition time profile that accounts for its unique characteristics (oil deposits, flow conditions, manufacturing tolerances), allowing each to operate optimally without excessive mechanical stress.
Solution Approach 2:
The patent implements dynamics by continuously adapting the ignition time through detection modes that monitor knocking events in real-time. The control device dynamically adjusts ignition times based on detected knocking, transitioning between different ignition time profiles to balance efficiency and mechanical stress protection.
2Manufacturing precision
If cylinder pressure sensors or alternative sensors are used to equalize peak firing pressure, then the manufacturing precision is improved, but the device complexity increases
Solution Approach 1:
The patent applies self-service by using the engine's own knocking events as the detection mechanism. The knocking detection system utilizes vibrations and sounds naturally produced by the engine during knocking events, eliminating the need for external sensor systems like cylinder pressure sensors. The control device leverages the engine's inherent acoustic signatures to identify and equalize cylinder performance.
Solution Approach 2:
The patent replaces complex mechanical sensor systems with an acoustic/vibration-based detection system. Instead of using cylinder pressure sensors or ion current sensors that require physical contact and complex signal processing, the system uses microphones or vibration sensors to detect knocking sounds, simplifying the overall system architecture.
3Reliability
If the ignition time is retarded to reduce mechanical stress, then the reliability is improved, but the efficiency decreases
Solution Approach 1:
The patent implements dynamics by continuously adapting the ignition time through detection modes that monitor knocking events in real-time. The control device dynamically adjusts ignition times based on detected knocking, transitioning between different ignition time profiles to balance efficiency and mechanical stress protection.
Solution Approach 2:
The patent applies parameter changes by adjusting the ignition time profile based on detected knocking events. When knocking is detected, the system changes the ignition timing parameter to a retarded position to reduce mechanical stress, and when no knocking is detected, it advances the ignition time to maximize efficiency.
4Object-generated harmful factors
If the engine operates closer to the misfire limit to reduce nitrogen oxide emissions, then the environmental performance is improved, but the stability of operation deteriorates
Solution Approach 1:
The patent applies local quality by individualizing the ignition time for each piston-cylinder unit based on its specific knocking behavior. Instead of a uniform ignition time for all cylinders, each cylinder receives a tailored ignition time profile that accounts for its unique characteristics (oil deposits, flow conditions, manufacturing tolerances), allowing each to operate optimally without excessive mechanical stress.
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 identifies and reduces high-ignition-pressure cylinders, minimizing wear and extending maintenance intervals while reducing nitrogen oxide emissions by operating the engine closer to the misfire limit, thereby reducing the spread of peak firing pressures and enhancing efficiency.
Implementation Method 1
a sensor device (3) for the cylinder-specific detection of knocking
Implementation Method 2
a sensor device (3) for the cylinder-specific detection of knocking
Data Source
AI summary
A method of operating an internal combustion engine with at least one piston-cylinder unit, and preferably a plurality of the piston-cylinder units, whereby, in a detection mode of the internal combustion engine one or more knock-promoting measures are taken until knocking has occurred in at least one piston-cylinder unit, and the measure(s) is/are intensified until a termination criterion is reached, whereby it is detected in which of the piston-cylinder units knocking has occurred, and whereby, in piston-cylinder units detected as knocking, the ignition time for a normal operating mode of the internal combustion engine is retarded.