Engine Control Device Managing Cold-Start Combustion Noise
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Solution Overview
Problem
Conventional control devices for internal combustion engines fail to maintain a two-peak cylinder pressure rise pattern during cold engine states, leading to increased combustion noise due to longer ignition delay and potential incomplete fuel burning.
Innovation Solution
A control device that adjusts fuel injection amounts and timings by increasing the pre-fuel injection and decreasing the second main fuel injection when the engine temperature is below a certain threshold, ensuring staged heat generation and reducing combustion noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the main fuel injection is divided into two to perform premix charged compressive ignition, then the combustion noise is reduced during warm state, but the ignition delay time becomes excessively long during cold state causing single-peak pressure waveform and increased combustion noise
Solution Approach 1:
The fuel injection is divided into three separate injections (pre-fuel injection, first main fuel injection, and second main fuel injection) instead of two, with the pre-fuel injection providing early ignition to reduce the effective ignition delay time while maintaining the staged combustion benefits for noise reduction
Solution Approach 2:
The injection timing and amount parameters are dynamically adjusted based on engine temperature. During cold state, the pre-fuel injection amount is increased and timed earlier to compensate for longer ignition delay, while during warm state the standard two-peak combustion pattern is maintained
2Loss of time
If the pre-fuel injection amount is increased during cold state to reduce ignition delay, then the combustion noise increases due to excessive fuel burning at the same timing, but if the pre-fuel injection amount is kept standard, then the ignition delay remains excessively long
Solution Approach 1:
The control device uses feedback from engine temperature sensors to dynamically adjust the pre-fuel injection amount and timing. The ECU monitors engine temperature and selects appropriate injection parameters from stored maps, ensuring optimal combustion pattern adaptation to cold or warm engine states
Solution Approach 2:
The injection strategy transitions from a static two-injection pattern to a dynamic three-injection pattern where the pre-fuel injection parameters (amount, timing) are continuously adjusted based on real-time engine temperature conditions to optimize both ignition delay and combustion noise
3Productivity
If the fuel injection timing is advanced to compensate for longer ignition delay during cold state, then the combustion efficiency improves, but the combustion noise increases due to premature fuel injection
Solution Approach 1:
By segmenting the fuel injection into three distinct phases (pre-fuel, first main, second main), the system can advance the pre-fuel injection timing to improve combustion efficiency while the subsequent main injections are timed to avoid excessive noise, distributing the combustion events across different phases
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 solution effectively maintains a three-peak cylinder pressure rise pattern even at cold states, reducing combustion noise and preventing soot formation by optimizing fuel ignitability and premixing times.
Implementation Method 1
a fuel injector injecting fuel into a combustion chamber of the engine body
Implementation Method 2
perform premix charged compressive ignition so that heat is generated inside the combustion chamber in stages a plurality of times
Data Source
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AI summary
A control device (200) for an internal combustion engine (100) keeping down an increase in combustion noise at the time of a cold state, provided with a combustion control part successively performing at least pre-fuel injection, first main fuel injection, and second main fuel injection to perform premix charged compressive ignition so that heat is generated inside the combustion chamber (11) in stages a plurality of times, the combustion control part comprising a target value setting part setting target injection amounts and target injection timings of the pre-fuel injection, first main fuel injection, and second main fuel injection and a correction part performing correction to make the target injection amount of the pre-fuel injection increase and make the target injection amount of the second main injection decrease when the temperature of the engine body (1) or the temperature of a parameter with a correlative relationship with the temperature of the engine body (1) becomes a predetermined temperature or less.