Internal Combustion Engine Cylinder Groups with Different Compression Ratios
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Solution Overview
Problem
Cylinder deactivation techniques in internal combustion engines lead to increased load on active cylinders, resulting in limited fuel savings and operational limitations due to gas escape and oil flow issues, and are not effectively optimized for varying load conditions.
Innovation Solution
Dividing cylinders into two groups with different compression ratios and fuel injection timing, where one group is always active for low loads and the other is active on demand for high loads, with separate supercharging and exhaust systems to optimize efficiency and minimize fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If cylinder deactivation technique is used to save fuel, then fuel consumption is reduced, but the load on active cylinders increases causing limited fuel savings and operational limitations
Solution Approach 1:
The engine is divided into two separate groups of cylinders (first group and second group) with different compression ratios. The first group operates at high compression ratio for fuel efficiency, while the second group operates at low compression ratio for high load conditions. This segmentation allows the engine to optimize fuel consumption without the reliability issues of traditional cylinder deactivation.
Solution Approach 2:
Different compression ratios are applied to different cylinder groups based on operating conditions. The first group of cylinders has a first compression ratio optimized for fuel efficiency, while the second group has a second compression ratio optimized for high load performance. This local differentiation of compression ratios allows each group to operate in its optimal range.
2Use of energy by moving object
If compression ratio is increased to improve fuel efficiency, then fuel consumption is reduced, but engine complexity and manufacturing cost increase
Solution Approach 1:
The engine is segmented into two cylinder groups with different compression ratios. This segmentation allows the high compression ratio group to achieve fuel efficiency while the low compression ratio group handles high load conditions, avoiding the need for complex variable compression ratio mechanisms in all cylinders.
Solution Approach 2:
The engine dynamically switches between different compression ratio configurations by activating different cylinder groups based on operating conditions. This dynamic adaptation allows the engine to maintain fuel efficiency across varying loads without requiring mechanically complex variable compression systems.
3Use of energy by moving object
If cylinder deactivation is used to reduce load, then fuel savings are achieved, but gas escape through piston segments causes vacuum and oil flow to combustion chamber
Solution Approach 1:
The engine is divided into two active cylinder groups that operate simultaneously or alternately, eliminating the need to deactivate entire cylinders. This prevents the formation of vacuum conditions that would cause oil to be drawn into the combustion chamber through piston segments.
Solution Approach 2:
The first group of cylinders continues to operate continuously with high compression ratio, providing continuous combustion action that prevents vacuum formation and oil ingress issues associated with complete cylinder deactivation.
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 approach allows for reduced fuel consumption while maintaining engine performance, with improved efficiency at low and high loads by alternating combustion between cylinder groups and optimizing fuel injection and supercharging for each condition.
Implementation Method 1
the first group of cylinders has a first compression ratio that is greater than the compression ratio of the second group of cylinders
Implementation Method 2
the first group of cylinders has a fuel injection timing advance that is lower than a fuel injection timing advance of the second group of cylinders
Implementation Method 3
the Diesel or Otto thermodynamic cycles are alternately divided between the two groups of cylinders. This implies obtaining the burning of the mixture alternately between the two groups of cylinders
Implementation Method 4
the Diesel or Otto thermodynamic cycles are alternately divided between the two groups of cylinders
Data Source
Figure 1
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Figure 4
AI summary
Internal combustion engine comprising a plurality of cylinders with relative pistons, connected to a relative common drive shaft, said multitude of cylinders being divided into a first group and a second group of cylinders, in which consecutive ignition cycles alternate between the two groups of cylinders, the first group of cylinders being controlled to be always active, and the second group of cylinders being controlled to be active on request, the engine being characterised in that said first group of cylinders has a compression ratio different from a compression ratio of said second group of cylinders.