Exhaust Manifold Junction Deflector Reduces Inter-Cylinder Disturbance
Solution Overview
Problem
Inter-cylinder disturbance of exhaust gas flow in internal combustion engine exhaust manifolds reduces overall exhaust gas power available for downstream components like turbochargers, due to backflow of exhaust gases affecting upstream cylinder discharge.
Innovation Solution
The exhaust manifold design features a first inlet passage with a smaller cross-sectional area than a second inlet passage, connected to a main passage with a smaller cross-sectional area at a junction, creating a deflector effect that accelerates exhaust gas past the junction and reduces backflow by forming a vortex in a widening section, directing flow downstream and minimizing upstream flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If exhaust gas flow is conducted from multiple cylinders through a common main passage, then the exhaust manifold can collect exhaust gas from multiple cylinders, but inter-cylinder disturbance occurs where exhaust gas from one cylinder flows backwards and disturbs the discharge from upstream cylinders
Solution Approach 1:
The patent applies local quality by creating a deflector effect at the specific location where the first inlet passage connects to the main passage. The smaller cross-sectional area at the junction creates localized flow acceleration that generates a vortex, which acts as a barrier to prevent upstream flow disturbance while allowing downstream flow to proceed normally.
Solution Approach 2:
The patent implements preliminary anti-action by designing the junction geometry to preemptively counteract the harmful backflow effect. The reduced cross-sectional area at the junction creates a deflector effect that generates a vortex before the exhaust gas can cause upstream disturbance, thereby preventing the harmful effect before it propagates.
2Speed
If the cross-sectional area of inlet passages and main passage is reduced to create a deflector effect, then exhaust gas flow acceleration and vortex formation occur to reduce backflow, but the passage dimensions are constrained
Solution Approach 1:
The patent applies parameter changes by modifying the cross-sectional area parameter of the inlet passage and main passage at the junction location. The first inlet passage has a smaller cross-sectional area than the second inlet passage, and the main passage has a smaller cross-sectional area at the junction than upstream, creating the necessary conditions for flow acceleration and vortex formation.
3Productivity
If the first inlet passage has a smaller cross-sectional area than the second inlet passage, then exhaust gas from the first cylinder is accelerated past the junction, but the junction geometry becomes more complex
Solution Approach 1:
The patent applies local quality by making the cross-sectional area reduction localized to the junction region of the first inlet passage, rather than throughout the entire passage. This allows the deflector effect to be generated at the critical location while keeping the rest of the inlet passages simple and easy to manufacture.
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 configuration effectively reduces inter-cylinder disturbance, ensuring reliable exhaust gas flow in the downstream direction and maintaining consistent exhaust gas properties towards the outlet, enhancing the utilization of exhaust gas power in downstream systems.
Implementation Method 1
A first portion of the first inlet passage at the intersecting wall portion has a first inlet passage cross sectional area, and the first inlet passage cross sectional area is smaller than a second inlet passage cross sectional area of a second portion of the first inlet passage located upstream of the first portion of the first inlet passage
Implementation Method 2
creating a deflector effect that accelerates exhaust gas past the junction and reduces backflow by forming a vortex in a widening section, directing flow downstream and minimizing upstream flow
Data Source
Figure 1
Figure 2~3
AI summary
Herein an exhaust manifold (2) is disclosed. A first inlet passage (8) connects to a main passage (12) at a junction. An intersecting wall portion (20) between the first inlet passage (8) and the main passage (12) forms an upstream end portion of the junction. A first portion (22) of the first inlet passage (8) has a first inlet passage cross sectional area (24). The first inlet passage cross sectional area (24) is smaller than a second inlet passage cross sectional area (28) of a second portion (26) of the first inlet passage (8) upstream of the first portion (22) of the first inlet passage (8). The main passage (12) comprises a first main passage portion (30) at the intersecting wall portion (20). The first main passage portion (30) having a first main passage cross sectional area (32). The first main passage cross sectional area (32) is smaller than a second main passage cross sectional area (48) of a second main passage portion (40) upstream of the junction (18).