Spark Plug Ionisation Current for Engine Phase Identification
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Solution Overview
Problem
Current methods for identifying the compression phase in internal combustion engines, such as those using sensors on the camshaft or forcing combustion failure, are unreliable and can lead to engine damage.
Innovation Solution
Measuring the ionisation current developed during combustion in each cylinder using a Control Unit and a device that produces ionisation current, allowing for accurate identification of the compression phase by comparing average ionisation current signals with a predetermined value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensors are positioned on the cam shaft for phase identification, then phase identification can be performed, but sensor functioning failure may occur leading to unreliable operation
Solution Approach 1:
The patent extracts the phase identification function from external sensors on the cam shaft and relocates it to the spark plug already present in the engine. The spark plug serves dual functions: generating spark for combustion and detecting ionization current for phase identification, eliminating the need for separate identification sensors and improving reliability.
Solution Approach 2:
The spark plug is given a multi-functional role: it performs its primary function of generating electrical spark for combustion while simultaneously serving as a sensor for detecting ionization current during the compression stroke. This universal application eliminates additional components and reduces system complexity.
2Measurement precision
If combustion failure is forced for phase identification, then phase identification can be achieved, but engine damage and anomalous functioning occur
Solution Approach 1:
The patent converts the normally harmful or wasted ionization current present during compression into a useful signal for phase identification. Instead of causing combustion failure as in prior methods, the system utilizes the natural ionization that occurs during the compression stroke to detect the compression phase, turning a passive electrical phenomenon into an active detection mechanism without damaging the engine.
Solution Approach 2:
The engine's own electrical system provides the detection signal. The ionization current that naturally occurs during compression is measured by the spark plug, allowing the engine to self-identify its phase without external intervention or forced combustion failure. The system uses its own operational characteristics for self-diagnosis.
3Reliability
If ionisation current measurement is used for phase identification, then reliable and accurate identification is achieved, but additional measurement and control equipment is required
Solution Approach 1:
The Control Unit leverages existing engine management components to perform phase identification. The spark plug serves dual purposes (combustion and sensing), and the Control Unit utilizes signals already present in the engine's electrical system, minimizing the need for additional dedicated equipment while achieving reliable identification.
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
Enables reliable and accurate identification of the compression phase within the third engine turn, preventing engine damage and ensuring proper functioning.
Implementation Method 1
the spark necessary to realise the combustion inside the cylinder
Implementation Method 2
the ionisation current developed during the combustion of the mixture in each cylinder
Data Source
AI summary
The invention relates to the field of method and devices therefore for identifying which cylinder is in the compression phase in a gasoline indirect electronic injection internal combustion engine.The present invention develops over various phases, measuring the signal of the ionisation current of each cylinder in which the piston is located at the top dead centre, registering the average value thereof and comparing it with a predetermined value.