Electrically-Heated Catalyst Base Material Stagnant Period Control
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Solution Overview
Problem
The existing technologies for electrically-heated catalyst devices in vehicles face deterioration issues when water is present, leading to temperature differences and potential damage due to rapid pressure increases during heating, which existing low electric power control methods do not adequately address.
Innovation Solution
An electronic control unit is implemented to determine if the conductive base material is in a stagnant temperature zone due to internal water content, and adjusts the electric power supply to lower levels when water is present, with the power supply being controlled based on the internal water content to prevent excessive heating and temperature differences.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If low electric power control is performed to prevent bumping and base material deterioration, then base material strength is improved, but warm-up time increases
Solution Approach 1:
The system performs preliminary detection of water content in the base material before heating begins. By detecting water content in advance and predicting the stagnant period, the control system can prepare appropriate power supply strategies beforehand, preventing base material deterioration while minimizing warm-up time through optimized heating schedules
Solution Approach 2:
The control system continuously monitors base material temperature and detects stagnant periods where temperature stops increasing despite continued heating. This feedback mechanism allows the system to identify when water evaporation is occurring and adjust power supply accordingly - reducing power during stagnant periods to prevent deterioration, then resuming normal power once the stagnant period ends, thus balancing protection with efficient warm-up
2Speed
If normal electric power supply is maintained during heating, then warm-up speed is improved, but base material deterioration occurs due to temperature difference
Solution Approach 1:
The control system dynamically adjusts electric power supply based on real-time detection of heating state and stagnant periods. Rather than using fixed power levels, the system varies power supply - maintaining normal power during active heating phases for fast warm-up, and reducing power during detected stagnant periods to prevent excessive temperature differences and base material deterioration, thus achieving both speed and reliability
3Reliability
If electric power is reduced during stagnant period to prevent deterioration, then base material reliability is improved, but heating efficiency decreases
Solution Approach 1:
The control system implements periodic heating cycles with alternating power levels. During non-stagnant periods, normal high power is applied for efficient heating. When stagnant periods are detected, power is temporarily reduced to prevent deterioration. This periodic alternation between high-power efficient heating and low-power protective phases maintains overall heating efficiency while ensuring base material reliability
Solution Approach 2:
The system detects and identifies stagnant periods, then strategically skips or reduces power supply only during these specific periods rather than continuously. This allows the system to rush through the heating process at high power during productive phases while briefly pausing or slowing during stagnant periods to prevent deterioration, minimizing the impact on overall heating efficiency
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 solution effectively reduces the risk of deterioration by controlling the heating rate of the base material dry region, thereby preventing excessive internal temperature differences and prolonging the warm-up time of the catalyst device.
Implementation Method 1
a conductive base material that generates heat upon being energized
Implementation Method 2
when the base material made of a porous body is heated in the state where water is contained in the base material, bumping may occur inside the base material, so that vapor may be generated
Data Source
AI summary
A vehicle includes an internal combustion engine, an electrically-heated catalyst device provided in an exhaust passage thereof, and an electronic control unit configured to control base material electric power supply supplied to a conductive base material. The catalyst device includes the conductive base material that generates heat upon energization, and a catalyst heated through the conductive base material. The electronic control unit determines whether the conductive base material is in a stagnant period, where temperature of the conductive base material partially stagnates in a prescribed temperature zone, the stagnant period occurring when water is present inside the catalyst device in a process of increase in temperature of the conductive base material. When determining that the conductive base material is in the stagnant period, the electronic control unit controls the base material electric power supply to be lower than when determining otherwise.