Ionisation Current Detonation Assessment via High-Pass Filtering
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Solution Overview
Problem
Current methods for evaluating detonation in internal combustion engines, relying on piezoelectric sensors, are prone to failure due to signal disturbances and cannot accurately assess detonation levels in all engine types, leading to potential engine damage from vibrations.
Innovation Solution
A method utilizing the ionisation current generated by a device comprising a coil, spark plug, polarisation circuit, and acquisition circuit, measured and processed by a Control Unit with a high-pass filter, to accurately evaluate detonation without sensors, correlating ion count with energy produced by the air-combustible mix.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If piezoelectric sensors are used to evaluate detonation, then detonation evaluation can be performed, but the sensors are prone to failure due to signal disturbances
Solution Approach 1:
The patent replaces the mechanical piezoelectric sensor system with an electrical measurement system. Instead of using physical sensors that convert mechanical vibrations to electrical signals, the invention directly measures ionization current in the combustion chamber, substituting a mechanical measurement approach with an electrical one that is less susceptible to signal disturbances and sensor failures.
Solution Approach 2:
The patent introduces ionization current as an intermediary measurement parameter. Rather than directly measuring mechanical vibrations from detonation, the system uses ionization current - which is naturally present in the combustion chamber during combustion - as a mediator to indirectly assess detonation levels, thereby avoiding the need for physical sensors that are prone to failure.
2Measurement precision
If piezoelectric sensors with band-pass filter are used, then detonation energy can be calculated, but the method fails in some engine types due to high signal disturbance
Solution Approach 1:
The patent replaces the mechanical vibration-based measurement system (piezoelectric sensors requiring band-pass filtering) with an electrical ionization current measurement system. This substitution eliminates the need for complex signal filtering and makes the measurement reliable across different engine types without being affected by high signal disturbance conditions.
3Measurement precision
If ionisation current is used to evaluate detonation, then accurate per-cylinder assessment is achieved, but requires additional device components
Solution Approach 1:
The patent makes the spark plug multi-functional by having it serve both its primary function of generating sparks for combustion and a secondary function of measuring ionization current for detonation assessment. This universality eliminates the need for separate dedicated sensors in each cylinder, thereby reducing overall device complexity while achieving accurate per-cylinder detonation evaluation.
Solution Approach 2:
The patent merges the spark plug and ionization current measurement functionality into a single integrated device. By combining these functions, the system avoids the complexity of installing and managing separate sensors for each cylinder, reducing device complexity while maintaining precise per-cylinder detonation assessment capability.
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 provides a reliable and accurate assessment of detonation levels in each cylinder, reducing the risk of engine damage by correlating ionisation current measurements with energy output, thereby enhancing engine fine-tuning and operation.
Implementation Method 1
a device positioned on each cylinder of said engine... comprises a coil, a spark plug... generates and measures the ionisation current, indispensable to implement the method in question, and a cylinder (2), into which the fuel is injected
Implementation Method 2
generates and measures the ionisation current, indispensable to implement the method in question... said ionisation current being ions produced during the combustion of the fuel in each cylinder of said engine
Implementation Method 3
The present invention is based on the use of the ionisation current generated by a device positioned on each cylinder of said engine... measured and processed by means performing the method of the present invention which are installed into a Control Unit (3) endowed with a high-pass filter with cut-off frequency between 2 KHz and 8 KHz (9)
Implementation Method 4
a device positioned on each cylinder of said engine... comprises a coil, a spark plug... necessary to generate the combustion inside the cylinder
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to the field of methods and devices for evaluating the knocking inside every cylinder of an internal combustion engine by making advantageous use of the ionisation current generated during the combustion of the fuel in each cylinder of said engine. The invention develops over various phases, each of which is repeated continually for each cycle of said combustion engine and is characterised by the fact that ionisation current values are selected during determined lengths of time, and said values are entered in a high-pass filter, the values determined by said filter then being squared and the value Vd calculated, said value being the relation between the value of the sum of the squares of said values obtained by said filter and a known normalisation coefficient, thus generating the spark at the spark plug in each cylinder on the basis of said value Vd.