Inter-cylinder Communication Means for HCCI Engine Torque
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Solution Overview
Problem
Internal combustion engines face challenges in reducing fuel consumption and emissions, particularly in achieving high torque and efficient HCCI operation due to limitations in intercylinder gas channel control and exhaust gas recirculation, which restricts the operating range and fuel efficiency.
Innovation Solution
The engine design includes communication means between cylinders to allow the transfer of combustion products during specific phases of the piston movement, enabling a 'supercharge' of combustion products into the second cylinder, which increases volumetric efficiency and allows HCCI combustion with higher fuel content without exceeding NOx emission limits, and can be used in SI and diesel operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If exhaust gas recirculation is used to reduce NOx emissions, then emissions are reduced, but the amount of exhaust gases introduced into cylinders is limited which reduces fuel efficiency
Solution Approach 1:
The patent divides the exhaust gas recirculation system into separate pathways for different cylinders. Each cylinder has dedicated communication channels that allow selective introduction of exhaust gases from specific other cylinders, enabling optimized EGR rates for each cylinder independently rather than using a common exhaust manifold for all cylinders.
Solution Approach 2:
The patent introduces exhaust gases into cylinders during the inlet stroke before combustion occurs. This preliminary introduction of hot exhaust gases pre-heats the fresh charge and prepares the combustion chamber for more efficient combustion, improving fuel efficiency while still achieving emission reduction.
2Loss of energy
If HCCI operation is used to reduce fuel consumption, then fuel consumption is reduced, but the operating range is restricted due to torque limitations
Solution Approach 1:
The patent introduces exhaust gases into cylinders during the inlet stroke before HCCI combustion occurs. This preliminary heating of the fresh charge by the hot exhaust gases raises the initial temperature of the combustion mixture, enabling HCCI to operate successfully at lower engine speeds and higher torque conditions where the temperature would otherwise be insufficient for auto-ignition.
Solution Approach 2:
The patent changes the temperature parameter of the fresh charge by introducing hot exhaust gases. This temperature increase allows HCCI operation to be extended to a broader range of operating conditions including lower engine speeds and higher torque requirements, thereby expanding the operating range while maintaining fuel efficiency benefits.
3Device complexity
If intercylinder gas channels are controlled by valves sharing camshafts with ordinary inlet and exhaust valves, then device complexity is reduced, but the possibility to regulate intercylinder gas channel timing is limited
Solution Approach 1:
The patent segments the valve control system by providing separate camshafts for intercylinder gas channel valves and ordinary inlet/exhaust valves. This segmentation allows independent timing control of intercylinder gas channels without affecting the timing of standard valve operations, providing the flexibility needed for optimized intercylinder communication timing.
Solution Approach 2:
The patent implements variable timing control for the intercylinder gas channel valves through dedicated camshafts that can be independently adjusted. This dynamic timing adjustment capability allows the system to optimize intercylinder gas exchange at different operating conditions while maintaining simple mechanical valve actuation through cam-follower mechanisms.
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 achieves a significant increase in maximum torque for HCCI operation, up to 2-4 times, while reducing emissions and fuel consumption, and allows for continuous use of all cylinders in HCCI, SI, or diesel modes with improved volumetric efficiency and emission reductions.
Implementation Method 1
provide communication between at least a first of the cylinders, at which a first piston is provided, and a second of the cylinders, at which a second piston is provided, during at least a part of an engine operation period starting during a movement of the first piston towards a bottom dead center position at a work stroke of the first cylinder
Data Source
AI summary
The invention relates to an internal combustion engine comprising at least two cylinders, at each of which at least one inlet for at least one combustion ingredient is provided. The engine comprises communication means, adapted to provide communication between at least a first of the cylinders, at which a first piston is provided, and a second of the cylinders, at which a second piston is provided, during at least a part of an engine operation period starting during a movement of the first piston towards a bottom dead center (BDC) position at a work stroke of the first cylinder and ending during a movement of the first piston away from the bottom dead center (BDC) position, during which engine operation period the second piston moves towards a bottom dead center (BDC) position and/or away from the bottom dead center (BDC) position.