Per-Cylinder Pressure Control in Internal Combustion Engines
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Solution Overview
Problem
Internal combustion engines face challenges in controlling peak cylinder pressure, which can lead to component damage due to extreme environmental conditions, and existing methods reduce engine output torque or are not applicable on an individual cylinder basis.
Innovation Solution
The system recirculates exhaust gas (EGR) into the intake manifold and adjusts fuel injection timing for each cylinder, using an Engine Control Module to monitor and control peak pressures, allowing for individual cylinder management without reducing torque output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If global turbocharger control is used to limit peak firing pressure, then peak firing pressure is controlled, but engine torque output is substantially reduced
Solution Approach 1:
The invention divides the engine into individual cylinders, each with its own pressure sensor and control capability. The ECU controls peak firing pressure on a per-cylinder basis rather than globally, allowing selective management of pressure in specific cylinders without reducing overall engine torque output. This segmentation enables precise local control while maintaining global performance.
Solution Approach 2:
The system applies different control strategies to different cylinders based on their individual pressure conditions. Each cylinder can have customized fuel injection timing and EGR valve control applied to it, allowing local optimization of pressure control without affecting other cylinders' torque production. This local quality approach maintains overall engine power while controlling pressure where needed.
2Stress or pressure
If global EGR control is applied to all cylinders, then combustion is controlled globally, but individual cylinder pressure management is not achieved
Solution Approach 1:
The control system is segmented to provide both global and local control functions. The ECU receives pressure signals from individual cylinder sensors and can independently adjust EGR valve positioning and fuel injection timing for each cylinder. This allows the system to maintain global combustion management while adding individualized pressure control capability to each cylinder.
Solution Approach 2:
The system dynamically adjusts control parameters based on real-time pressure feedback from each cylinder. The ECU continuously monitors individual cylinder pressures and modifies EGR valve positioning and injection timing accordingly, enabling adaptive control that responds to changing conditions in each specific cylinder while maintaining overall engine management.
3Power
If fuel injection timing is adjusted globally, then combustion timing is controlled, but individual cylinder pressure variations cannot be addressed
Solution Approach 1:
The system implements segmented control where each cylinder has dedicated pressure sensing and control actuation. Individual pressure sensors in each cylinder provide precise local measurements to the ECU, which then adjusts fuel injection timing and EGR valve positioning specifically for that cylinder. This segmentation enables precise measurement and control at the individual cylinder level while maintaining overall combustion efficiency.
Solution Approach 2:
The system uses feedback from individual cylinder pressure sensors to continuously adjust control parameters. The ECU receives real-time pressure data from each cylinder and modifies fuel injection timing and EGR valve positioning based on the measured pressure deviations. This feedback mechanism enables precise individual cylinder pressure control while maintaining efficient overall combustion.
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 limits peak cylinder pressure across all cylinders while maintaining fuel efficiency and torque production, preventing component damage from excessive pressure without the need for global turbocharger control.
Implementation Method 1
means for recirculating a portion of the engine exhaust gas (EGR) into the intake manifold
Implementation Method 2
Each engine cylinder is provided with a pressure sensor, and a peak cylinder pressure signal is sent to the ECM during each firing cycle
Implementation Method 3
the timing of the individual cylinder fuel injectors of the engine
Implementation Method 4
Peak firing pressure is affected by the combustion process and the conditions of the incoming combustion air
Data Source
AI summary
An Engine Control Module includes an electronic controller for controlling the position of an EGR valve, the timing of opening and closing of the engine combustion valves, and the timing of the individual cylinder fuel injectors of an engine. Each engine cylinder includes a pressure sensor. Peak cylinder pressure is sent to the ECM during each firing cycle. The ECM is programmed with required maximum percentages of EGR and optimal combustion valve timing for each engine operating condition, and sets the EGR valve and/or the camshaft phaser accordingly to adjust combustion in all the engine cylinders. The ECM also compares the measured peak pressure for each cylinder and adjusts the timing of fuel injection for the next firing cycle to trim the measured peak pressure in each cylinder to a predetermined level at or below the maximum allowable peak firing pressure for the engine.