Multi-Cylinder Engine Combustion Control via Heat Release Feedback
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Solution Overview
Problem
Multi-cylinder internal combustion engines face inefficiencies and emission challenges due to variations in cylinder operation, such as different charge air pressures and timing discrepancies in inlet valve systems, which affect combustion processes and overall engine performance.
Innovation Solution
A method and computer control system that determine cumulative and mean gross heat release rates from combustion cycles, using these values as feedback to accurately control combustion in each cylinder, either individually or collectively, by adjusting inlet valve and supercharger operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the timing of inlet valves is adjusted to reduce emissions, then exhaust gas emission requirements are met, but engine performance may suffer
Solution Approach 1:
The patent implements feedback control by continuously monitoring cylinder pressure and calculating polytropic indices to determine compression pressures. This feedback loop allows real-time adjustment of inlet valve timing based on actual cylinder conditions, enabling emission reduction while maintaining engine performance through dynamic optimization rather than static adjustments.
Solution Approach 2:
The system changes operational parameters by adjusting inlet valve timing based on calculated compression pressures and polytropic indices. This parameter adaptation allows the engine to optimize combustion conditions for both emission reduction and performance maintenance, transitioning from fixed timing to variable timing control.
2Productivity
If variable inlet valve systems are adjusted to balance cylinder operation, then combustion efficiency improves, but even small timing delays or advances cause major pressure differences between cylinders
Solution Approach 1:
The patent uses feedback control by measuring cylinder pressure, calculating polytropic indices, and determining compression pressures for each cylinder. This feedback mechanism enables real-time detection and correction of pressure imbalances, allowing precise adjustment of inlet valve timing to maintain balanced cylinder operation while optimizing combustion efficiency.
Solution Approach 2:
The system applies local quality control by individually monitoring and adjusting inlet valve timing for each cylinder based on its specific compression pressure and polytropic index. This cylinder-specific control approach addresses local pressure imbalances without affecting other cylinders, enabling precise optimization of each cylinder's combustion process.
3Measurement precision
If cylinder pressure is monitored and polytropic index is determined for each cylinder, then compression pressure can be accurately estimated, but the system complexity increases
Solution Approach 1:
The patent replaces complex mechanical measurement systems with computational methods. Instead of using complex mechanical sensors and actuators to directly measure and control compression pressure, the system uses mathematical calculations based on cylinder pressure measurements and polytropic index determination. This substitution of mechanical systems with computational algorithms reduces physical complexity while maintaining high measurement precision.
Solution Approach 2:
The polytropic index serves as an intermediary parameter that simplifies the control system. By introducing this intermediate calculation step, the system can estimate compression pressure without requiring direct measurement, reducing the need for complex sensors and actuators while maintaining accurate control.
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 enables precise cylinder-wise and collective combustion control, enhancing engine efficiency and reducing emissions by ensuring balanced air admission and optimized combustion processes across all cylinders.
Implementation Method 1
combustion of fuel in a multi-cylinder internal combustion engine
Implementation Method 2
determining a cumulative heat release from combustion of fuel during successive combustion cycles in each cylinder of the engine, determining a mean gross heat release rate from combustion of fuel
Data Source
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AI summary
Invention relates to a method of controlling combustion of fuel in a multi-cylinder internal combustion engine (10), comprising step of –determining a cumulative heat release (Q) from combustion of fuel during successive combustion cycles in a cylinder of the engine, – determining a mean gross heat release rate (Q') from combustion of fuel during successive combustion cycles in the cylinder of the engine, – using the mean gross heat release rate (Q') as feedback to control the combustion in the cylinder of the engine. Invention relates also to a computer control system (100) configured to control combustion process in a multi-cylinder internal combustion piston engine (10).