Internal Combustion Engine Control for High RPM Stability
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Solution Overview
Problem
Internal combustion engines experience uncontrolled large increases in rpm when load is suddenly reduced, leading to high component stress and deteriorated exhaust gas values due to self-ignitions, which are exacerbated by the tendency for the mixture in the combustion chamber to ignite automatically at high temperatures and pressures.
Innovation Solution
The engine is controlled to have fewer combustions than engine cycles in the same time interval, particularly in the high rpm range above the rated rpm and below the regulating range, by interrupting ignition or reducing fuel metering, ensuring that self-ignitions are prevented by maintaining high pressure and temperature conditions that inhibit subsequent combustions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the ignition is interrupted to limit rpm, then the rpm can be reduced, but self-ignitions still occur causing uncontrolled rpm increase
Solution Approach 1:
The invention applies preliminary action by suppressing ignitions in advance before they can cause uncontrolled rpm increases. The control unit proactively prevents ignitions when the rpm is approaching the regulating range, rather than reacting after self-ignitions have already occurred. This anticipatory suppression ensures that the rpm remains within the desired range without experiencing uncontrolled increases from self-ignitions.
Solution Approach 2:
The invention implements feedback control by continuously monitoring the rpm and adjusting the ignition suppression strategy accordingly. When the rpm is in the high rpm range and approaching the regulating range, the control unit increases ignition suppression. This closed-loop feedback ensures that the rpm remains stable and prevents uncontrolled increases while adapting to changing engine conditions.
2Power
If combustions occur for each engine cycle, then the engine produces continuous power, but self-ignitions increase the tendency for uncontrolled rpm increase
Solution Approach 1:
The invention applies partial action by selectively suppressing ignitions only in specific engine cycles when the rpm is in the high rpm range and approaching the regulating range. Instead of suppressing all ignitions continuously, the control unit applies suppression partially and selectively, maintaining power production in normal conditions while preventing self-ignitions only when necessary. This selective approach minimizes the impact on engine power while effectively preventing harmful self-ignitions.
3Adaptability or versatility
If the load is suddenly reduced, then the rpm increases, but self-ignitions exacerbate the uncontrolled rpm increase
Solution Approach 1:
The invention applies preliminary anti-action by implementing ignition suppression as a countermeasure before self-ignitions can exacerbate the rpm increase following sudden load reduction. When the control unit detects that the rpm is in the high rpm range and approaching the regulating range, it proactively suppresses ignitions to prevent the positive feedback loop that would otherwise cause uncontrolled rpm increases. This anticipatory counter-action stabilizes the rpm despite sudden load changes.
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 control method effectively reduces the likelihood of self-ignitions, thereby preventing uncontrolled rpm increases and maintaining engine stability, ensuring that the engine operates within a regulated range by ensuring that no self-ignitions occur, even in high rpm conditions.
Implementation Method 1
an ignition unit for igniting an air/fuel mixture in the combustion chamber
Implementation Method 2
the air/fuel mixture, which is formed in the combustion chamber, is ignited in the region of the top dead center of the piston
Data Source
AI summary
An internal combustion engine includes a cylinder (2) wherein a combustion chamber (5) is formed. The engine also includes devices for metering fuel and combustion air as well as an ignition device for igniting the mixture in the combustion chamber (5). A method for operating the internal combustion engine provides that fuel and combustion air are supplied to the engine and the mixture is ignited in the combustion chamber (5). The combustion chamber (5) is delimited by a piston (7) which drives a crankshaft (25) rotatably journalled in a crankcase (3). A control is provided which controls the supply of fuel and the ignition of the mixture in the combustion chamber (5). The internal combustion engine is so controlled in at least one operating state that the number of combustions is less than the number of engine cycles in the same time span. To avoid the formation of self ignitions, the operating state is a high rpm range wherein the rpm lies above the rated rpm and below the rpm in a regulating range.