Engine Control Unit Signal Estimation for Knock Prevention
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Solution Overview
Problem
Traditional engine devices face difficulties in maintaining operation when output signals are lost, particularly in large-size engines for ships and power generators, leading to issues with air-fuel ratio control, knocking, and reduced combustion efficiency, which can result in unstable engine rotation and potential damage.
Innovation Solution
An engine device with a control unit that estimates output signals based on fuel gas injection amounts and executes combustion control, including multiple steps of ignition timing retardation and advancement to maintain stable operation and prevent knocking, even when primary output signals are lost, ensuring continuous operation until an auxiliary engine is stabilized.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the engine device operates without output signals, then the operation can be sustained temporarily, but the air-fuel ratio control becomes inaccurate leading to knocking or misfire
Solution Approach 1:
The control unit creates a copy of the output signal by estimating it from the fuel gas injection amount when the actual output signal is lost. This estimated output signal serves as a substitute to maintain control functions, allowing the engine to continue operating while preserving adequate control precision through the relationship between fuel injection and engine output.
2Object-affected harmful factors
If the ignition timing is retarded to avoid knocking, then knocking is prevented, but combustion efficiency is reduced
Solution Approach 1:
The ignition timing is made dynamically adjustable based on real-time monitoring of combustion states. When knocking is detected, the ignition timing is retarded to prevent damage. When no knocking occurs, the ignition timing is advanced or maintained at optimal values to maximize combustion efficiency. This dynamic adjustment allows the system to adapt to changing conditions and balance knocking prevention with energy efficiency.
Solution Approach 2:
The control unit continuously monitors combustion states and uses this feedback to adjust ignition timing. By detecting knocking events and responding with timing adjustments, the system creates a closed-loop control that prevents knocking while minimizing the impact on combustion efficiency through timely corrections.
3Stability of the object's composition
If the air flow rate is increased to prevent misfire, then combustion stability is improved, but knocking may occur due to excessively high air flow
Solution Approach 1:
The air flow rate is dynamically adjusted based on real-time detection of combustion states. When misfire is detected, the air flow rate is increased to improve combustion stability. When knocking is detected, the air flow rate is reduced to prevent damage. This dynamic control allows the system to maintain optimal combustion stability while preventing knocking through continuous adaptation to changing conditions.
Solution Approach 2:
The control unit uses feedback from combustion state monitoring to adjust air flow rate. By detecting misfire events and responding with air flow increases, or detecting knocking and responding with air flow reductions, the system creates a closed-loop control that balances combustion stability with knocking prevention.
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 solution prevents emergency stops, ensures propulsion means for navigation, and maintains stable engine operation by accurately controlling air-fuel ratios and ignition timing, even in the absence of primary output signals, thereby preventing damage and ensuring safe navigation or power generation.
Implementation Method 1
combust the same (see Patent Literature 1 and Patent Literature 2; hereinafter PTL 1 and PTL 2, respectively)
Data Source
AI summary
An engine device of including: an intake manifold configured to supply air into a cylinder; a gas injector configured to mix fuel gas with air supplied from the intake manifold, and supply mixed gas to the cylinder; an igniter configured to ignite, in the cylinder, premixed fuel obtained by pre-mixing the fuel gas with the air; and a control unit configured to execute a combustion control of a premixed fuel based on the output signal indicative of an output from the engine device. When the air amount is determined to be insufficient and when the output signal is lost, the control unit estimates an output signal based on the fuel gas injection amount from the gas injector, and executes the combustion control based on the estimated output signal.