Ion Sense Feedback for Engine Combustion Control
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Solution Overview
Problem
Achieving stable and controlled combustion in internal combustion engines with multiple spark plugs is challenging, as uncontrolled burn rates can lead to harsh combustion conditions, affecting fuel economy, emissions, and consumer satisfaction.
Innovation Solution
A system and method that uses individual spark plug control and ionization current sensing to determine a desired combustion burn rate by analyzing signals from each spark plug, adjusting ignition timing, and controlling actuators such as charge motion, fuel injectors, and EGR valves to manage combustion within a selected cylinder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple spark plugs are employed to facilitate fast burn, then combustion burn rate is improved, but combustion stability deteriorates
Solution Approach 1:
The patent divides the combustion control into individual cylinder control and individual spark plug control within each cylinder. By segmenting the combustion chamber into multiple independently controllable zones (cylinders) and further segmenting each cylinder into multiple spark plug regions, the system can optimize burn rate while maintaining stability through localized adjustments.
Solution Approach 2:
The patent implements closed-loop feedback control using ionization current sensing to monitor combustion quality and timing in real-time. The controller uses this feedback to continuously adjust ignition timing, fuel injection, and other actuators to maintain desired combustion characteristics, resolving the stability issue while preserving fast burn rates.
2Use of energy by moving object
If combustion burn rate is increased to reduce emissions and improve fuel economy, then fuel economy is improved, but noise, vibration, and harshness worsen
Solution Approach 1:
The ionization current sensing system provides real-time feedback on combustion characteristics, enabling the controller to detect and correct combustion events that would produce excessive NVH. This allows the system to maintain high burn rates for fuel economy while actively suppressing harmful combustion characteristics.
Solution Approach 2:
The patent employs dynamic adjustment of ignition timing and combustion control parameters based on real-time sensor feedback. This dynamic control allows the system to optimize burn rate for fuel economy while adaptively adjusting to prevent harsh combustion conditions, balancing performance with comfort.
3Measurement precision
If ionization current sensing is used to control combustion, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent makes the spark plugs serve dual functions: traditional ignition and ionization sensing. By making the spark plugs multi-functional, the system achieves precise combustion measurement without adding separate sensing hardware, thereby reducing overall device complexity while maintaining high measurement precision.
Solution Approach 2:
The spark plugs perform self-diagnosis and self-monitoring by generating ionization current signals that provide information about combustion quality and timing. This self-service capability eliminates the need for additional complex sensing systems while achieving precise measurement of combustion parameters.
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 allows for precise control of combustion, improving fuel economy, reducing emissions, and maintaining acceptable noise, vibration, and harshness (NVH) levels by accurately managing combustion burn rates through ionization sensing feedback.
Implementation Method 1
ionization current sensing (or ion sense) uses a bias voltage applied across a sensor positioned within the combustion chamber to generate a current signal indicative of the combustion quality and timing
Implementation Method 2
For spark-ignition engines, one or more spark plugs may be used as an ion sensor with the bias voltage applied across the air gap of the spark plug
Implementation Method 3
controlling an internal combustion engine having at least one spark plug per cylinder with individual plug control and ionization current sensing
Data Source
AI summary
A system and method for operating an engine having at least two spark plugs per cylinder include controlling at least one actuator to alter combustion within a selected cylinder such that the combustion burn rate determined by ion sense current signals associated with the at least two spark plugs of the selected cylinder approaches a desired combustion burn rate. A desired combustion burn rate is determined based on current engine/vehicle operating and ambient conditions with ion sense signals from each spark plug analyzed to determine combustion timing relative to corresponding ignition timing. Ignition timing and/or other actuators are controlled in response to provide a desired combustion burn rate.