Internal Combustion Engine Variable Piston Stroke Mechanism
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Solution Overview
Problem
Internal combustion engines lack the ability to dynamically adjust piston stroke ratios between different cycles, limiting their operational efficiency and adaptability to varying operating conditions.
Innovation Solution
The integration of an eccentric shaft with a phase adjuster allows for adjustable coupling with the crankshaft, enabling stepless variation of piston stroke ratios between compression, expansion, and exhaust strokes, thereby enhancing control over the engine's operating behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional crankshaft mechanism is used, then the engine structure is simple, but the piston stroke ratio between different cycles cannot be adjusted
Solution Approach 1:
The patent applies the dynamics principle by introducing an adjustable coupling mechanism between the eccentric shaft and crankshaft. The coupling angle can be dynamically changed during operation, allowing the piston stroke ratio to be adjusted according to different operating conditions. This transforms a static crankshaft mechanism into a dynamic system that can adapt to varying requirements.
Solution Approach 2:
The patent segments the crankshaft mechanism into two independent rotational components: the crankshaft itself and the eccentric shaft. By decoupling these two elements and allowing independent rotation with adjustable phase relationship, the system gains the ability to vary piston stroke ratios without fundamentally redesigning the entire engine mechanism.
2Productivity
If the eccentric shaft is added to enable stroke adjustment, then the operating efficiency is improved, but the device complexity increases
Solution Approach 1:
The eccentric shaft serves multiple functions simultaneously: it acts as a rotational element for stroke adjustment, a coupling element to the crankshaft, and a mechanism for varying the piston stroke ratio. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving improved operating efficiency.
3Use of energy by moving object
If the phase adjuster is used to vary compression and expansion stroke ratios, then the energy utilization is optimized, but the control system complexity increases
Solution Approach 1:
The phase adjuster changes the phase angle parameter between the eccentric shaft and crankshaft rotation. By varying this single parameter (the phase difference), the system can optimize compression and expansion stroke ratios for different operating conditions without requiring complex control mechanisms, thereby improving energy utilization with relatively simple control.
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 improves engine efficiency by allowing for variable Atkinson and inverted Atkinson cycles, optimizing energy utilization, reducing exhaust gas pressure, and enhancing power density and response behavior across different load ranges.
Implementation Method 1
An eccentric shaft (13) is coupled to the crankshaft (3) and to the piston (2) in such a way that strokes of this piston can be adjusted, at least temporarily or in at least one operating state, through the eccentric shaft (13)
Data Source
AI summary
An internal combustion engine includes a crankshaft and at least one piston coupled to the crankshaft for executing strokes in a cylinder as a result of rotation of the crankshaft. An eccentric shaft is coupled to the crankshaft and to the piston in such a way that strokes of the piston are adjusted by the eccentric shaft. A phase adjuster adjusts a phase of the coupling of the eccentric shaft to the crankshaft.