Rotary Dedicated EGR Engine for Combustion Stability
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Solution Overview
Problem
Dedicated exhaust gas recirculation engines face challenges in achieving uniform recirculated exhaust gas flow due to the pulsed nature of exhaust gas generation, leading to combustion instability and cylinder-to-cylinder pressure imbalances, which are not adequately addressed by existing systems without the use of complex mixers.
Innovation Solution
Incorporating a rotary engine as a dedicated exhaust gas recirculation source, which provides a more consistent and even distribution of recirculated exhaust gas across multiple combustion cycles, reducing the need for exhaust gas recirculation mixers and improving engine flexibility and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a reciprocating piston engine with dedicated exhaust gas cylinders is used, then the system complexity remains relatively low, but the flexibility in operation is limited and combustion stability is reduced due to pulsed exhaust gas flow
Solution Approach 1:
The patent applies the dynamics principle by transitioning from a reciprocating piston engine to a rotary engine configuration. The rotary engine's continuous rotational motion enables smooth, continuous exhaust gas flow rather than pulsed flow, significantly improving operational flexibility and combustion stability while maintaining reasonable system complexity. The rotary design allows for variable operating conditions and better adaptation to different load requirements.
Solution Approach 2:
The patent addresses the periodic action issue by eliminating the periodic/pulsed nature of exhaust gas generation. The rotary engine produces exhaust gas continuously rather than in discrete pulses corresponding to each combustion cycle, thereby stabilizing the exhaust gas recirculation flow and improving combustion consistency across all cylinders.
2Device complexity
If exhaust gas is recirculated from a dedicated cylinder in a reciprocating engine, then the system structure is simple, but combustion stability deteriorates due to pulsed exhaust gas flow and cylinder-to-cylinder pressure imbalances
Solution Approach 1:
The rotary engine configuration transforms the static, pulsed exhaust gas flow into a dynamic, continuous flow. This continuous flow pattern stabilizes the exhaust gas recirculation process, ensuring consistent combustion conditions across all cylinders and eliminating the combustion stability issues inherent in reciprocating engine designs.
Solution Approach 2:
The patent implements continuity of useful action by ensuring that exhaust gas is generated and recirculated continuously rather than in discrete pulses. The rotary engine's continuous rotation maintains a steady stream of exhaust gas, which is then continuously recirculated to the intake manifold, providing stable combustion conditions and eliminating cylinder-to-cylinder pressure imbalances.
3Stability of the object's composition
If an exhaust gas recirculation mixer is added to mitigate pulsed exhaust gas flow, then combustion stability improves, but device complexity increases
Solution Approach 1:
The rotary engine configuration inherently provides continuous exhaust gas flow, eliminating the need for additional mixing devices. The dynamic rotational motion of the rotary engine naturally smooths out the exhaust gas flow, achieving combustion stability without adding the complexity of an exhaust gas recirculation mixer or similar corrective components.
Solution Approach 2:
The rotary engine design is self-service in that it automatically provides the benefit of continuous, smooth exhaust gas flow through its inherent mechanical design. No additional components or active control systems are required to mitigate pulsed flow effects—the rotary configuration itself performs the flow-smoothing function that would otherwise require separate mixing devices.
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
The use of a rotary engine enhances combustion stability and reduces torque fluctuations, allowing for more efficient and flexible operation by providing a steady supply of recirculated exhaust gas, thereby improving engine performance and reducing the complexity of exhaust gas recirculation systems.
Implementation Method 1
The second mixture is combusted in the rotary combustion chamber, wherein the combustion generates a recirculated exhaust gas that applies pressure to the rotor
Implementation Method 2
The secondary crankshaft is coupled to the primary crankshaft by a gear mechanism
Data Source
AI summary
An engine and a method of operating the engine wherein fuel, intake air, and recirculated exhaust gas provides a first mixture, which is inducted into a first combustion cylinder. The first mixture is combusted in the combustion cylinder to generate a first exhaust gas that applies pressure to a piston within the combustion cylinder, reciprocating the piston and rotating a primary crankshaft coupled to the piston. Fuel and intake air, which provides a second mixture, are inducted into a rotary combustion chamber. The second mixture is combusted in the rotary combustion chamber, wherein the combustion generates a recirculated exhaust gas that applies pressure to the rotor and rotates the rotor and a secondary crankshaft coupled to the rotor. The secondary crankshaft is coupled to the primary crankshaft by a gear mechanism. The recirculated exhaust gas is exhausted into an exhaust gas recirculation loop and recirculated.