Compression Ignition Engine Speed Control via Dynamic Fuel Injection
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Solution Overview
Problem
Compression ignition engines face challenges in quickly passing through resonance speed ranges without excessive torque fluctuation and combustion noise, which leads to increased vehicle vibrations and noise.
Innovation Solution
A method and system for controlling a compression ignition engine that adjusts fuel injection amounts based on current engine speed and in-cylinder temperature to optimize engine speed passage through resonance speed ranges, reducing torque fluctuations and noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a relatively large fuel injection amount is set from the start of the engine to the completion of the start, then the torque of the engine increases and the engine speed quickly passes through the resonance speed range, but the torque fluctuation increases and the vibration of the entire vehicle increases
Solution Approach 1:
The fuel injection amount is dynamically adjusted based on the detected engine speed. When the engine speed is below the resonance speed range, a larger fuel injection amount is supplied to increase torque and accelerate engine speed. When the engine speed reaches or exceeds the resonance speed range, the fuel injection amount is reduced to minimize torque fluctuation and vehicle vibration. This dynamic adjustment resolves the contradiction between achieving quick start-up and reducing harmful vibrations.
Solution Approach 2:
The control device changes the fuel injection amount parameter according to the engine speed parameter. By setting different fuel injection amounts based on whether the engine speed is below or above the resonance speed range, the system optimizes both the speed increase and the reduction of torque fluctuation, thereby resolving the technical contradiction.
2Speed
If a relatively large fuel injection amount is maintained to increase torque, then the engine speed increases quickly, but the combustion noise becomes large
Solution Approach 1:
The fuel injection amount is dynamically controlled based on real-time engine speed detection. During the initial phase when engine speed is below the resonance speed range, larger fuel injection amounts are used to achieve quick acceleration. Once the engine speed reaches the resonance speed range, the fuel injection amount is automatically reduced, which simultaneously decreases combustion noise while maintaining adequate engine speed. This dynamic control strategy resolves the contradiction between speed increase and noise reduction.
Solution Approach 2:
The control device adjusts the fuel injection amount parameter in response to changes in engine speed parameter. By transitioning from a larger fuel injection amount to a smaller fuel injection amount as the engine speed approaches the resonance speed range, the system effectively reduces combustion noise while preserving the benefit of quick engine start-up.
3Loss of time
If the engine speed is increased quickly to pass through the resonance speed range, then the start-up is completed quickly, but the vibration of the vehicle is increased due to torque fluctuation
Solution Approach 1:
The control device implements dynamic fuel injection control that adapts to the engine's operating conditions. During the critical phase when engine speed is below the resonance speed range, larger fuel injection amounts are supplied to minimize start-up time. When the engine speed reaches the resonance speed range, the fuel injection amount is reduced to minimize torque fluctuation and vehicle vibration. This time-dependent dynamic control resolves the contradiction between quick start-up and vibration reduction.
Solution Approach 2:
The fuel injection amount parameter is changed based on the engine speed parameter and the resonance speed range. By setting appropriate fuel injection amounts at different stages of engine start-up, the system achieves both quick passage through the resonance speed range and minimization of vehicle vibration, thereby resolving the technical contradiction.
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 method allows the engine speed to quickly pass through resonance speed ranges while minimizing vehicle vibrations and combustion noise by dynamically adjusting fuel injection amounts, thereby improving engine start-up efficiency and reducing noise.
Implementation Method 1
a compression ignition engine having a fuel injection valve which supplies fuel into a combustion chamber
Implementation Method 2
a compression ignition engine has a larger compression ratio than a general spark-ignited engine, and therefore exhibits relatively great fluctuation of the torque. When the torque fluctuation is increased, the vibration of the entire vehicle due to the torque fluctuation is increased.
Data Source
AI summary
A system for controlling a compression ignition engine includes: a speed obtaining section which detects or estimates an engine speed achieved by combustion in an n-th cycle; and an injection amount setting section which sets, in a start period after the start of cranking, a fuel injection amount to be injected by injectors in an (n+1)-th cycle. If the engine speed achieved by the combustion in the n-th cycle falls in the resonance range, the injection amount setting section sets the fuel injection amount for an (n+1)-th cycle to be larger than the fuel injection amount injected when the engine speed is higher than or equal to an upper limit of the resonance range.