Internal Combustion Engine Cylinder Fuel Cut-Off Control
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Solution Overview
Problem
Conventional internal combustion engines lack detailed control mechanisms for fuel cut-off during abnormal combustion events like heavy knock or misfire, leading to potential mechanical damage and increased emissions, as they either immediately stop the engine or fail to manage fuel supply effectively.
Innovation Solution
A method and control device that adjust the burning state of each cylinder through fuel regulation, including fuel cut-off, based on measurements such as cylinder pressures and exhaust gas temperatures, allowing for partial fuel injection with a pilot fuel to maintain controlled combustion and prevent excessive fuel leakage, with a limited number of attempts to restore main fuel injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If main fuel injection is cut off immediately upon detection of abnormal combustion, then mechanical damage is prevented, but engine productivity is reduced due to immediate shutdown
Solution Approach 1:
The control system dynamically adjusts the fuel injection strategy based on the severity and persistence of abnormal combustion. Instead of immediate shutdown, the system transitions between different operational states (normal operation, restricted injection, fuel cut-off) based on real-time sensor data and counter values, allowing the engine to maintain operation when possible while protecting against damage when necessary
Solution Approach 2:
The system changes the fuel injection parameter (from normal injection to restricted injection to complete cut-off) based on the detected abnormal combustion conditions. The control unit modifies injection parameters dynamically, using counters to track the duration of abnormal combustion and adjusting fuel delivery accordingly to balance protection and continuity
2Object-generated harmful factors
If fuel supply is cut off to a misfiring cylinder, then emissions are reduced, but fuel leakage to exhaust pipe occurs if gas engine
Solution Approach 1:
Instead of complete fuel cut-off, the system applies restricted fuel injection where only a limited amount of fuel is supplied to the misfiring cylinder. This partial action is sufficient to prevent unburned fuel from reaching the exhaust pipe and causing explosion, while also reducing emissions compared to complete fuel supply
Solution Approach 2:
The control system continuously monitors combustion status through sensors (knock sensors, exhaust gas temperature sensors) and adjusts fuel injection in real-time. When abnormal combustion is detected, the system provides feedback to the injection control to implement restricted injection or cut-off, and continues monitoring to determine when normal operation can resume
3Productivity
If engine operation continues during abnormal combustion, then productivity is maintained, but mechanical damage risk increases
Solution Approach 1:
The control system dynamically evaluates the severity of abnormal combustion using multiple parameters (knock intensity, exhaust gas temperature, duration of abnormal combustion) and adjusts operation accordingly. The system allows continued operation for minor or transient abnormalities while implementing protective measures for severe or persistent conditions
Solution Approach 2:
The system implements progressive protective measures before complete shutdown is necessary. Restricted fuel injection serves as a cushioning measure that reduces the severity of abnormal combustion and prevents progression to conditions that would require immediate shutdown, thereby protecting mechanical components while maintaining operation
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 manages abnormal combustion by reducing the risk of mechanical damage and emissions, allowing for controlled engine operation and minimizing fuel leakage, while ensuring the engine can recover from abnormal conditions without immediate shutdown.
Implementation Method 1
measuring exhaust gas temperature of the cylinder in restricted injection state
Implementation Method 2
based on measurements, such as cylinder pressures
Implementation Method 3
cylinder knock
Implementation Method 4
the fuel injection is kept partially active with a pilot fuel injected by pilot injector of said cylinder
Data Source
AI summary
An internal combustion engine uses gaseous main fuel and liquid pilot fuel and has a plurality of cylinders and an engine controller capable of adjusting a burning state of each cylinder through fuel regulation, including fuel cut off, upon occurrence of abnormal combustion. A method of operating the internal combustion engine includes, upon occurrence of abnormal combustion in a cylinder in a gaseous mode, cutting off the main fuel into only the cylinder and the fuel injection is kept partially active with a pilot fuel injected by a pilot nozzle of the cylinder.