Variable Compression Ratio Engine Piston Control for Carbon Deposit Removal
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Solution Overview
Problem
Variable compression ratio engines face challenges in maintaining reliable piston performance and preventing carbon buildup and wear steps due to varying compression ratios, leading to potential engine damage and increased maintenance needs.
Innovation Solution
A variable compression ratio engine with a control unit that adjusts the piston's clearance position temporarily to remove carbon deposits, using a predetermined scheme to gradually change the clearance position and induce piston movements to clean the cylinder inner wall, while maintaining a preset compression ratio for optimal performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the compression ratio is varied by changing the maximum and minimum positions of the piston, then optimal performance over the whole operating range is achieved, but carbon build up and wear steps occur in the cylinder above the piston top dead position
Solution Approach 1:
The invention applies periodic action by implementing a control unit that periodically adjusts the clearance position of the piston to a temporal clearance position above the preset position. This periodic adjustment allows the piston to temporarily reach higher positions in the cylinder, cleaning carbon deposits from the cylinder wall above the normal operating range, before returning to the preset clearance position for normal operation.
2Reliability
If the piston clearance position is adjusted to remove carbon deposits, then reliable piston running performance is improved, but the compression ratio varies from the optimal preset value
Solution Approach 1:
The invention applies preliminary action by proactively adjusting the piston clearance position to a temporal position before carbon deposits become problematic. The control unit monitors operating conditions and preemptively moves the piston to clean the cylinder wall, preventing severe carbon buildup that would harm performance, then returns to the optimal preset position.
Solution Approach 2:
The control unit implements periodic adjustments between the preset clearance position and the temporal clearance position. These periodic actions allow the system to maintain both reliable piston performance (by periodically cleaning deposits) and optimal engine performance (by returning to the preset position for combustion).
Data Source
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Figure 4a
AI summary
The invention relates to a variable compression ratio (VCR) engine and a method for driving a variable compression ratio (VCR) engine. The variable compression ratio (VCR) engine (1), comprises at least one cylinder (2) with a piston (3) movably arranged within the cylinder (2), adapted to perform a predefined piston stroke within the cylinder (2), and a setting unit (4) for setting a preset compression ratio by setting a preset clearance position (11). The VCR-engine (1) further comprises a control unit (5) for setting at least one temporal clearance (15) position different from the preset clearance position (11) and for inducing at least one piston movement with the temporal clearance position (15).