Internal Combustion Engine Knock Control via Dynamic EGR
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Solution Overview
Problem
Abnormal combustion processes such as pre-ignition, knocking, or misfiring occur in internal combustion engines when the air-to-fuel ratio is outside a certain range, leading to inefficient and high-pollution operation.
Innovation Solution
An internal combustion engine with a control unit that adjusts exhaust gas recirculation rate, ignition timing, and fuel supply based on a knock index determined by pressure sensors, distinguishing between oscillations caused by ignition and knocking events to prevent abnormal combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If exhaust gas recirculation rate is increased to prevent knocking, then knocking prevention is improved, but fuel efficiency deteriorates and pollution increases
Solution Approach 1:
The system dynamically adjusts the exhaust gas recirculation rate based on real-time knock detection. The control unit continuously monitors cylinder pressure signals and modifies the EGR rate accordingly, transitioning from static to dynamic control to optimize both knocking prevention and fuel efficiency.
Solution Approach 2:
The system implements feedback control by using pressure sensors to detect knock events and feeding this information back to the control unit. The control unit then adjusts the exhaust gas recirculation rate based on this feedback, creating a closed-loop system that balances knocking prevention with fuel efficiency.
2Reliability
If exhaust gas recirculation rate is increased to prevent knocking, then knocking prevention is improved, but emission pollution increases
Solution Approach 1:
The system dynamically adjusts the exhaust gas recirculation rate based on real-time knock detection. The control unit continuously monitors cylinder pressure signals and modifies the EGR rate accordingly, transitioning from static to dynamic control to optimize both knocking prevention and fuel efficiency.
Solution Approach 2:
The system implements feedback control by using pressure sensors to detect knock events and feeding this information back to the control unit. The control unit then adjusts the exhaust gas recirculation rate based on this feedback, creating a closed-loop system that balances knocking prevention with fuel efficiency.
3Reliability
If pressure sensors and control systems are added to detect and prevent knocking, then knocking detection and control is improved, but device complexity increases
Solution Approach 1:
The system uses the engine's own operational parameters (cylinder pressure signals already present during combustion) for knock detection, rather than requiring entirely separate sensing systems. The control unit processes existing pressure data to identify knock events, reducing the need for additional complex hardware.
Solution Approach 2:
The system replaces complex mechanical knock detection mechanisms with electronic pressure sensing and signal processing. Instead of relying on mechanical sensors or complex mechanical systems, the invention uses pressure sensors combined with digital signal analysis to detect and control knocking.
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
Prevents knocking while maintaining optimal fuel efficiency and reducing pollution by dynamically adjusting engine parameters to ensure a stable combustion process.
Implementation Method 1
A signal representative for pressure within at least one cylinder is provided
Implementation Method 2
A knock index is determined on the basis of the signal
Implementation Method 3
the control unit is configured to adapt the exhaust gas recirculation rate
Implementation Method 4
Burning of gaseous fuel or of liquid and/or gaseous fuels in such engines is possible
Data Source
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AI summary
The present invention relates to an internal combustion engine (10) and to a method for operating a large vessel engine or a stationary engine, which is operable a least in a gas mode. The engine comprises at least one cylinder (11) having an inner diameter (12) of at least 200mm and comprising a pre-chamber, in particular comprising a pilot injection system (13). The engine comprises at least one gas admission valve (14) for supplying fluid fuel to the cylinder (11) , a, preferably low-pressure, exhaust gas recirculation path (16) and a pressure measuring unit (16) with at least one sensor (17) for providing a signal representative of a pressure within the at least one cylinder. The engine comprises a control unit (18) which is configured to receive the signal of the pressure measuring unit, to determine a knock index on basis of the signal, to compare the knock index with a predetermined knock index value or a knock index interval, and to adapt the EGR rate, the time of an ignition event and/or the amount of supplied fluid fuel if the determined knock index is below or above the knock index value or the knock index interval.