Compression Ignition Engine Control for Atmospheric Pressure Adaptation
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Solution Overview
Problem
Compression ignition engines face challenges in maintaining stable combustion and high thermal efficiency, especially under varying environmental conditions such as low atmospheric pressure and temperature fluctuations, leading to increased NOx emissions and combustion noise.
Innovation Solution
A control system for compression ignition engines that includes sensors for atmospheric pressure, temperature, and water temperature, which adjusts the air-fuel ratio and ignition timing to execute lean or rich compression ignition combustion modes, ensuring stable combustion and reducing NOx emissions and noise through real-time feedback control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the air-fuel ratio is made leaner to achieve high thermal efficiency and reduce NOx emissions, then fuel efficiency improves, but combustion stability deteriorates under low atmospheric pressure conditions
Solution Approach 1:
The control system dynamically adjusts ignition timing based on atmospheric pressure conditions. Under low atmospheric pressure, the ECU retards ignition timing to prevent premature combustion and maintain stability, while under normal conditions it optimizes timing for maximum thermal efficiency. This dynamic adaptation resolves the contradiction between efficiency and stability across varying operating conditions.
Solution Approach 2:
The system changes the ignition timing parameter in response to atmospheric pressure variations. By detecting atmospheric pressure with a sensor and adjusting the ignition timing parameter accordingly, the system maintains combustion stability across different environmental conditions while preserving thermal efficiency when conditions permit.
2Object-generated harmful factors
If ignition timing is retarded to suppress combustion noise, then combustion noise decreases, but thermal efficiency drops
Solution Approach 1:
The control system dynamically adjusts ignition timing based on atmospheric pressure conditions. Under low atmospheric pressure, the ECU retards ignition timing to prevent premature combustion and maintain stability, while under normal conditions it optimizes timing for maximum thermal efficiency. This dynamic adaptation resolves the contradiction between efficiency and stability across varying operating conditions.
Solution Approach 2:
The system changes the ignition timing parameter in response to atmospheric pressure variations. By detecting atmospheric pressure with a sensor and adjusting the ignition timing parameter accordingly, the system maintains combustion stability across different environmental conditions while preserving thermal efficiency when conditions permit.
3Adaptability or versatility
If the engine operates at high altitude with low atmospheric pressure, then adaptability to environmental conditions improves, but air intake becomes difficult leading to richer air-fuel ratio
Solution Approach 1:
The control system uses atmospheric pressure sensors to detect environmental conditions and provides feedback to the ECU. The ECU then adjusts fuel injection quantity and ignition timing based on this feedback, maintaining the appropriate lean air-fuel ratio even under low atmospheric pressure conditions by compensating for reduced air intake.
Solution Approach 2:
The system changes the ignition timing parameter in response to atmospheric pressure variations. By detecting atmospheric pressure with a sensor and adjusting the ignition timing parameter accordingly, the system maintains combustion stability across different environmental conditions while preserving thermal efficiency when conditions permit.
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
The system maintains high thermal efficiency and reduces NOx emissions and combustion noise by dynamically adjusting combustion modes based on environmental conditions, enhancing engine stability and emission performance.
Implementation Method 1
at least one sensor having a plurality of measuring parts including an atmospheric-pressure detector configured to detect an atmospheric pressure
Implementation Method 2
CI combustion is combustion started by the compressed self-ignition of mixture gas inside the combustion chamber
Implementation Method 3
The in-cylinder temperature increases according to an increase in the in-cylinder pressure
Implementation Method 4
SI combustion is combustion accompanied by the flame propagation started by forcibly igniting the mixture gas inside a combustion chamber
Implementation Method 5
combustion accompanied by the flame propagation started by forcibly igniting the mixture gas
Implementation Method 6
the start timing of CI combustion is advanced, and combustion noise increases
Data Source
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AI summary
A control system for a compression ignition engine configured to start compression ignition combustion by igniting mixture gas formed by injecting fuel into combustion chambers is provided, which includes combustion chambers each defined in respective cylinders so that displacements of the combustion chambers change by respective pistons reciprocating, a throttle valve, ignition plugs, injectors, a sensor having measuring parts including an atmospheric-pressure detector configured to detect an atmospheric pressure, and configured to measure parameters related to operation of the engine, and a controller. The controller executes a lean compression ignition combustion control in which compression ignition combustion is performed at a given lean air-fuel ratio higher than a stoichiometric air-fuel ratio. The controller restricts the execution of the lean compression ignition combustion control when the controller determines that the atmospheric pressure is lower than a given threshold based on a signal outputted from the atmospheric-pressure detector.