V-Engine Exhaust Asymmetry for Purification
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Solution Overview
Problem
Vehicles with V-engines experience uneven temperature rise characteristics and reduced engine output performance due to offset banks, leading to disparate catalytic converter lengths and purifying performance issues.
Innovation Solution
An exhaust system design where the second bank is offset to the rear, with catalytic converters positioned to have their centerlines extending to the lower portion of the vehicle, and a convergence section is placed under the dash panel closer to the second bank, allowing for unequal pipe lengths to be minimized and enhancing engine output by optimizing catalytic converter positioning and inclination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If catalytic converters are positioned at horizontally symmetrical positions with horizontally symmetrical inclinations, then the exhaust system structure is simplified, but the temperature rise characteristics become uneven and purifying performance decreases
Solution Approach 1:
The patent applies asymmetry by positioning the first catalytic converter at a frontward position with a greater angle of inclination toward the frontward portion, while the second catalytic converter is positioned at a rearward position with a smaller angle of inclination. This asymmetric configuration compensates for the bank offset in V-engines, equalizing the effective pipe lengths and temperature rise characteristics despite the asymmetric engine layout.
2Ease of manufacture
If the convergence section is positioned at the bank offset towards the rear of the vehicle, then the exhaust pipes can converge naturally, but the lengths of catalytic converters from output ports to convergence section become unequal, lowering engine output performance
Solution Approach 1:
The patent applies local quality by making the first catalytic converter have a greater angle of inclination toward the frontward portion compared to the second catalytic converter. This localized adjustment in inclination angle compensates for the asymmetric positioning, equalizing the effective exhaust path lengths from each bank to the convergence section, thereby maintaining balanced engine output performance.
Data Source
AI summary
An exhaust system for a V-engine vehicle with enhanced exhaust gas purifying capacity and output performance is provided. In the exhaust system, a second bank offset from a first bank backward in the longitudinal direction of the vehicle is mounted in an engine compartment (6) in front of a dash panel (5), and a first catalytic converter (28) is connected to a rear end portion of a first exhaust manifold (27) of the first bank; a second catalytic converter (30) is connected to a rear end portion of a second exhaust manifold (29) of the second bank. Furthermore, an inlet port (28a) of the first catalytic converter (28) is positioned at a frontward portion of the vehicle (1) with respect to an inlet port (30a) of the second catalytic converter (30) and the frontward angle of inclination of the center line of the first catalytic converter (28) is greater than that of the second catalytic converter (30).