Diesel Combustion System Design via Target Heat Release Rate Mapping
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Solution Overview
Problem
Current combustion system design for diesel engines is inefficient and time-consuming, relying on reverse design methods that generate numerous schemes, leading to increased calculation resources and prolonged research and development periods, without focusing on the mechanism relation between combustion system configuration and the combustion process.
Innovation Solution
A combustion system design method based on a target heat release rate, which involves obtaining an optimal heat release rate using a Miller and Sabathe cycle coupled model, simulating it with a double-Wiebe function, constructing a mapping relation among heat release rate, piston geometric parameters, and oil injection parameters, and solving for target parameters to design the combustion system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If reverse design with parameter crossed combinations is used, then comprehensive design schemes can be generated, but calculation time increases exponentially and calculation resources are consumed
Solution Approach 1:
The patent inverts the traditional reverse design approach by establishing a forward design methodology. Instead of generating multiple combustion chamber schemes and simulating them to find optimal parameters, the patent starts with target combustion parameters (heat release rate, combustion duration, combustion phasing) and directly calculates the corresponding combustion chamber geometric parameters using analytical formulas. This inversion eliminates the need for exhaustive parameter combinations and 3D simulations, reducing calculation time from exponential to polynomial complexity while maintaining design comprehensiveness through the systematic parameter mapping relationships.
2Adaptability or versatility
If reverse design with many parameter combinations is used, then design coverage is improved, but device complexity and calculation resource demands increase
Solution Approach 1:
The patent extracts the core functional relationships between combustion chamber geometry and combustion parameters by establishing analytical mapping formulas. Instead of using complex 3D simulation software and exhaustive parameter combinations, the patent extracts the essential relationships into direct calculation formulas that link geometric parameters (bowl radius, bowl depth, throat radius) directly to combustion characteristics (heat release rate, combustion duration, CA50). This extraction simplifies the design process from a complex multi-scheme evaluation approach to a straightforward parameter calculation approach, reducing device complexity while maintaining comprehensive design coverage.
3Adaptability or versatility
If experience-based reverse design is used, then design flexibility is maintained, but design accuracy and reliability depend on designer experience
Solution Approach 1:
The patent transforms the experience-based qualitative design process into a parameter-driven quantitative design process. By establishing analytical formulas that directly calculate combustion chamber geometric parameters from target combustion parameters, the patent enables precise control over combustion characteristics. Designers can specify exact heat release rates, combustion durations, and combustion phasing, and the formulas will provide the corresponding geometric parameters with high accuracy. This parameter transformation eliminates reliance on designer experience while maintaining design flexibility, as the systematic parameter relationships allow for easy adjustment of different combustion targets.
Data Source
AI summary
Disclosed is a combustion system design method based on a target heat release rate, which belongs to the technical field of diesel engine combustion chamber design. The method includes: obtaining an ideal heat release rate based on Sabathe-Miller cycle; simulating the ideal heat release rate based on a double-Wiebe function and obtaining the target heat release rate; constructing a mapping relation among the heat release rate, piston geometric parameters and fuel injection parameters, which includes target start of combustion being an function of fuel injection timing and ignition delay, premixed combustion parameters being functions of throat radius, injection pressure and nozzle diameter, and diffusion combustion being a function of piston pit depth; solving target piston geometric parameters and target fuel injection parameters based on the mapping relation; and then designing a combustion system. The method does not depend on experience and multi-scheme design, greatly shortens the combustion system design.