Internal Combustion Engine Intake Port Volume Optimization
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Solution Overview
Problem
Internal combustion engines face challenges in improving output performance and exhaust gas emission performance due to reverse flow of combustion gas into the intake system, which complicates the valve train system and increases costs.
Innovation Solution
The engine design incorporates a simplified valve train system with specific intake port volume ratios and valve overlap amounts, using a fixed valve timing type valve train to suppress reverse flow, allowing for improved combustion and emission performance without the need for variable valve timing, and a compact throttle body placement to reduce intake port volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a variable valve train is employed to reduce valve overlap period at low rotational speed to prevent reverse flow, then combustion performance and emission performance are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent applies parameter changes by optimizing the intake port volume ratio (Rv) to a specific range (0.45-0.65) and controlling the valve overlap period within 30-60 degrees crank angle. This allows the fixed valve train to achieve reverse flow suppression without requiring complex variable valve timing mechanisms, thus resolving the contradiction between preventing reverse flow and maintaining system simplicity
Solution Approach 2:
The patent employs a fixed valve train system with simple cam profiles instead of expensive variable valve timing mechanisms. By optimizing the intake port geometry and fixed valve timing parameters, the system achieves effective reverse flow prevention without the need for costly variable valve actuation systems, thereby selecting a simpler, more economical solution
2Power
If variable valve train is used to prolong valve overlap period at high rotational speed to improve output performance, then output performance is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent optimizes the valve overlap period parameter to within 30-60 degrees crank angle and the intake port volume ratio Rv to 0.45-0.65. These parameter optimizations enable the fixed valve train to achieve sufficient output performance across the operating range without requiring complex variable valve timing mechanisms to prolong overlap at high speeds
Solution Approach 2:
The patent designs a universal fixed valve train system with optimized cam profiles and intake port geometry that performs effectively across both low and high rotational speed ranges. The single fixed valve timing configuration serves multiple functions - preventing reverse flow at low speeds and maintaining adequate output at high speeds - eliminating the need for separate variable valve timing systems for different operating conditions
3Object-affected harmful factors
If valve lift curve is made sufficiently long to reduce noise upon valve seating, then noise is reduced, but valve opening period and valve lift amount are reduced resulting in reduced engine output
Solution Approach 1:
The patent optimizes the valve lift curve parameters and valve timing parameters within specific ranges to achieve a balance between noise reduction and output performance. The controlled valve overlap period (30-60 degrees) and intake port volume ratio (0.45-0.65) allow for sufficiently long valve lift curves that reduce seating noise while maintaining adequate valve opening duration and lift amount for engine output
Data Source
AI summary
An internal combustion engine is configured to satisfy the relation expressed by 0<Rv<0.000438×θ2−0.0407×θ+1.55 in a range of an intake valve overlap amount θ(°) from 20° to 45°, where Rv denotes an intake port volume ratio obtained by dividing an intake port internal volume Vp by a cylinder stroke volume Vc, and the intake valve overlap amount θ(°) is a crank angle from an intake valve opening timing when the intake valve starts opening to an intake top dead center of the piston. The engine improves output performance as well as both combustion performance and emission performance by suppressing reverse flow of the combustion gas into the intake system.