Saddle-Type Vehicle Exhaust Catalyst Deterioration Detection
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Solution Overview
Problem
Straddled vehicles face challenges in maintaining initial exhaust gas purification performance while avoiding increased size due to the need for larger catalysts, which restricts exhaust device layout and may lead to erroneous catalyst deterioration determinations from water exposure.
Innovation Solution
The vehicle includes a catalyst deterioration determination unit that assesses catalyst condition based on water exposure state, allowing for accurate detection of deterioration and enabling downsizing of the catalyst, thus maintaining performance without increasing vehicle size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the size of the catalyst is increased to maintain initial exhaust gas purification performance, then the purification performance is improved, but the layout freedom of the exhaust device is restricted and the vehicle size increases
Solution Approach 1:
The patent introduces a water exposition detection mechanism that dynamically adjusts catalyst deterioration determination based on environmental conditions. The system switches between different determination modes (first determination when water is detected, second determination when water is not detected) to accurately assess catalyst status without requiring oversized catalysts, thereby maintaining layout freedom while ensuring purification performance.
2Reliability
If the size of the catalyst is increased to maintain initial exhaust gas purification performance, then the purification performance is improved, but the vehicle size increases
Solution Approach 1:
The patent changes the determination parameters for catalyst deterioration by introducing water exposition state as a key parameter. The system uses different judgment criteria based on water detection status, allowing for accurate catalyst assessment with smaller catalyst sizes. This parameter change enables maintaining purification performance without increasing vehicle size.
3Device complexity
If the upstream exhaust passage member is exposed to water splashed up by wheels, then the detection of catalyst deterioration may become erroneous, but the layout freedom is improved
Solution Approach 1:
The patent introduces a water exposition detection device as an intermediary between the exhaust passage and the catalyst deterioration determination system. This intermediary detects water status and transmits this information to the determination unit, which then adjusts its judgment accordingly. This intermediary mechanism eliminates erroneous detections while allowing the exhaust passage to be positioned in locations with better layout freedom.
Data Source
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AI summary
The exhaust device (60) of the engine unit (11) of the straddled vehicle 1 includes a catalyst unit (62) and an upstream exhaust passage member 61. The catalyst unit (62) has a catalyst (62a) for purifying exhaust gas discharged from the engine main body (20). The upstream exhaust passage member (61) connects the engine main body (20) and the catalyst unit (62). At least a part of the upstream exhaust passage member (61) is disposed at a position which is exposed to water splashed up by at least one of the front wheel unit or the rear wheel unit. The upstream exhaust passage member water exposition detection unit (92) detects the water-exposition state of the upstream exhaust passage member (61) due to water splashed up by at least one of the front wheel unit (2) or the rear wheel unit (3). The catalyst degeneration determination unit (93) determines whether the catalyst (62a) is degenerated when the catalyst (62a) is in the active state. The catalyst degeneration determination unit (93) controls determination of whether the catalyst (62a) is degenerated based on the water-exposition state of the upstream exhaust passage member (61) where the state is detected by the upstream exhaust passage member water exposition detection unit (92).