Cylinder Pressure Balancing System for Engine Knock Mitigation
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Solution Overview
Problem
Existing methods for balancing internal combustion engine cylinders are delayed and typically only effective at high engine loads, failing to address cylinder-specific knock issues efficiently, leading to uneven work distribution and potential engine damage.
Innovation Solution
The system employs cylinder-specific pressure sensors to measure pressures and a control unit that adjusts fuel injection duration based on pressure deviations and knock values, allowing for real-time balancing and knock mitigation across varying engine loads without the need for separate knock sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If exhaust gas temperature measurement is used for balancing cylinders, then fuel amount adjustment can be performed, but there is a delay in the balancing response
Solution Approach 1:
The patent replaces the thermal measurement method (exhaust gas temperature) with a mechanical measurement method (cylinder pressure sensing). Pressure sensors directly measure the work performed in each cylinder through indicator diagrams, providing immediate feedback without the thermal delay inherent in exhaust gas temperature measurement. This substitution enables real-time balancing control.
2Reliability
If cylinder balancing is performed only at highest engine loads using knock sensors, then knock damage is prevented, but cylinders are not balanced at lower loads and the system is complex
Solution Approach 1:
The patent makes the cylinder pressure measurement system universal by enabling it to perform multiple functions: it detects cylinder work for balancing control at all load levels, detects knock conditions, and provides diagnostic information. This single pressure sensing system replaces the need for separate knock sensors and enables balancing across the entire operating range, not just at highest loads.
Solution Approach 2:
The system continuously monitors cylinder pressure and provides real-time feedback on both work distribution and knock conditions. The control unit processes pressure data to determine both balancing requirements and knock events, enabling simultaneous optimization of cylinder balance and knock protection across all operating conditions through continuous feedback control.
3Difficulty of detecting and measuring
If separate knock sensors are used for detecting knock, then knock detection is possible, but device complexity increases
Solution Approach 1:
The cylinder pressure sensor serves dual purposes: it measures indicator diagrams for cylinder work assessment and simultaneously detects knock events through analysis of pressure fluctuations. This multi-functional approach eliminates the need for separate knock sensors, reducing device complexity while maintaining comprehensive monitoring capability.
Solution Approach 2:
The patent merges the knock detection function with the cylinder work measurement function by using a single pressure sensing system for both purposes. The control unit integrates analysis of both steady-state pressure (for work calculation) and transient pressure fluctuations (for knock detection), combining multiple monitoring functions into one unified system.
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 immediate and precise balancing of cylinders at all load levels, reducing engine knock and ensuring smoother operation, allowing for higher load capacity and improved engine performance.
Implementation Method 1
cylinder-specific pressure sensors (1) installed in the cylinders for measuring the cylinder pressures
Implementation Method 2
Fuel is introduced into the cylinders of an internal combustion engine and combusted. The combustion of fuel releases energy which is converted into mechanical movement
Data Source
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AI summary
The invention relates to balancing the cylinders of an internal combustion engine. The invention comprises cylinder-specific pressure sensors (1) installed in the cylinders of an internal combustion engine for measuring the cylinder pressures as well as an adjustment unit (2). The adjustment unit is arranged to determine the maximum pressure and knock value of each cylinder as well as the mean maximum pressure of the cylinders as a response to the measurements of cylinder pressures and to determine the differences between the maximum pressure of each cylinder and the mean maximum pressure. The differences are compared to a certain deviation range of the mean maximum pressure and the knock value to a certain knock limit value. The duration of the fuel injection of the cylinder is adjusted in case the difference of a single cylinder exceeds the lower limit of the deviation range and the knock value of the cylinder is less than the knock limit value or the difference of the cylinders exceeds the upper limit of the deviation range.