Catalyst Deterioration Detection Using Exhaust Temperature Change Points
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Solution Overview
Problem
Conventional catalyst deterioration detecting systems are expensive due to the use of O2 sensors and are not suitable for actual driving environments, particularly during frequent acceleration and braking operations.
Innovation Solution
A catalyst deterioration detecting system that employs upstream and downstream temperature detection means to recognize change points in exhaust gas temperature during acceleration and deceleration operations, determining catalyst deterioration based on the difference between these change points, without relying on O2 sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If O2 sensors are used to detect catalyst deterioration, then measurement precision is improved, but device cost increases significantly
Solution Approach 1:
The patent replaces the chemical sensing mechanism of O2 sensors with a thermal detection system using temperature sensors. The system detects catalyst deterioration by measuring temperature differences and thermal response characteristics in the exhaust stream, substituting expensive chemical sensing with more affordable thermal sensing technology while maintaining detection capability
Solution Approach 2:
The patent employs inexpensive temperature sensors instead of costly O2 sensors, accepting that the temperature sensors can be simpler and more readily replaced. This approach uses lower-cost sensing elements that can be easily manufactured and installed, reducing overall system cost while achieving the detection function through alternative physical principles
2Ease of manufacture
If temperature difference detection is used without O2 sensors, then device cost is reduced, but reliability deteriorates in frequent acceleration and braking conditions
Solution Approach 1:
The patent employs periodic detection cycles during specific driving conditions (acceleration and deceleration phases) to accumulate sufficient thermal data. By conducting detections at regular intervals during these dynamic transitions, the system builds reliable temperature difference patterns that improve detection reliability under varying operating conditions without requiring O2 sensors
Solution Approach 2:
The patent monitors changes in temperature parameters over time rather than relying on static temperature differences. By tracking the rate of temperature change, the thermal response time, and the magnitude of temperature transitions during acceleration and deceleration, the system adapts to dynamic driving conditions and maintains reliable deterioration detection through parameter evolution analysis
3Ease of manufacture
If conventional temperature difference detection is used, then O2 sensor cost is avoided, but detection precision is insufficient for actual driving environments
Solution Approach 1:
The patent transitions from measuring only static temperature differences between upstream and downstream sensors to measuring the temporal dimension of thermal response. By incorporating the time component - how long it takes for temperature changes to propagate through the catalyst - the system adds a temporal dimension to the detection, enabling more precise deterioration assessment while maintaining cost-effectiveness
Solution Approach 2:
The patent employs dynamic thermal response analysis by monitoring how temperature parameters evolve during acceleration and deceleration events. Rather than relying on steady-state temperature differences, the system captures the dynamic behavior of heat transfer through the catalyst, using the rate and pattern of temperature changes to precisely detect deterioration while keeping sensor requirements simple and affordable
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 approach allows for the detection of catalyst deterioration in a cost-effective and versatile manner, suitable for various driving conditions, by utilizing temperature differences to assess the oxidation reaction delay, thereby indicating the degree of catalyst degradation.
Implementation Method 1
an upstream-side temperature detection means that detects a temperature of an exhaust on an upstream side of the catalyst; a downstream-side temperature detection means that detects a temperature of the exhaust on a downstream side of the catalyst
Data Source
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AI summary
A system (9) of the invention is a system for detecting deterioration of a catalyst (8) provided in an exhaust passage (12) of an internal combustion engine (11), the system including: means (5) that detects a temperature of an exhaust on an upstream side of the catalyst (8); means (6) that detects a temperature of the exhaust on a downstream side of the catalyst (8); a recognition unit (10) that recognizes, both upstream and downstream of the catalyst (8), a change point at which the temperature changes from temperature fall or constant temperature to temperature rise during acceleration operation, or a change point at which the temperature changes from temperature rise or constant temperature to temperature fall during deceleration operation; and a determination unit (10) that determines that the catalyst (8) has deteriorated when a difference (ΔT or ΔT') between the upstream and downstream change points becomes equal to or longer than a predetermined time.