Electric Heating Catalyst Control for Thermal Stress
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Solution Overview
Problem
Internal combustion engines with electric heating catalysts face the risk of catalyst support cracks due to temperature differences during rapid changes in intake air flow, particularly during acceleration and deceleration, which existing technologies fail to adequately address.
Innovation Solution
A control device and method that detects rapid changes in intake air flow and adjusts the energization of the catalyst support to maintain a uniform temperature distribution, preventing excessive temperature differences by energizing the support during acceleration and deceleration based on predetermined thresholds and conducting periods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the air-fuel ratio is transitioned toward a rich side during acceleration immediately after cold starting to reduce exhaust energy, then the temperature difference between catalyst support wall surface and vicinity is reduced, but this approach does not prevent temperature differences during rapid deceleration or other rapid air flow changes
Solution Approach 1:
The invention changes the control parameter from air-fuel ratio adjustment to direct electric heating of the catalyst support. By controlling the heating element embedded in the catalyst support, the system can directly regulate the temperature of the support structure itself, providing protection against temperature differences during all types of rapid air flow changes including both acceleration and deceleration conditions.
2Reliability
If no active temperature control is applied to the catalyst support, then the system remains simple, but cracks occur on the catalyst support due to temperature differences during rapid air flow changes
Solution Approach 1:
The invention merges the heating function with the catalyst support structure by embedding a heating element directly into the support. This integration allows the support to generate its own heat for temperature control, eliminating the need for separate external heating systems while providing reliable crack prevention through direct temperature management.
Solution Approach 2:
The catalyst support with embedded heating element serves itself by generating the heat it needs for temperature control. The system monitors temperature differences and activates the heating element within the support structure to maintain thermal uniformity, enabling the catalyst support to self-regulate its temperature without requiring complex external control systems.
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
Effectively suppresses the occurrence of cracks in the catalyst support by reducing temperature differences during rapid air flow changes, ensuring the longevity and performance of the catalyst.
Implementation Method 1
an electric heating catalyst having a catalyst support generating heat by energizing is disposed on an exhaust passage
Data Source
AI summary
According to one aspect of the present invention, there is provided a control device for an internal combustion engine, in which an electric heating catalyst (EHC) having a catalyst support generating heat by energizing is provided to an exhaust passage. The control device includes a control unit configured to energize the support in the case where a rapid change in intake air flow is detected based on an intake air flow of the internal combustion engine or a correlation value of the intake air flow, so as to suppress any occurrence of a crack caused by an increase in difference in temperature between predetermined portions at the support during the rapid change in intake air flow.