Catalyst Temperature Estimation in Variable Displacement Engines
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Solution Overview
Problem
Existing temperature models for catalytic converters in variable displacement V-6 engines fail to reliably estimate catalyst temperatures due to fluctuating exhaust gas temperatures, leading to inaccurate OBD measures and O2 sensor evaluations.
Innovation Solution
A method that estimates catalyst temperatures by setting initial values to a base model, applies cooldown corrections based on deactivation time, and updates estimates using a catalyst cooldown model, ensuring accurate temperature calculations even during cylinder bank deactivation and reactivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a base model temperature estimation method is used for catalytic converters in variable displacement engines, then the estimation is simple and computationally efficient, but the temperature estimates become unreliable when cylinder banks are deactivated and reactivated due to large exhaust gas temperature fluctuations
Solution Approach 1:
The temperature estimation is segmented into different modes: a base model for normal operation and a corrected model for deactivation/reactivation events. The system divides the estimation problem into distinct operational states, applying appropriate estimation methods to each segment, thereby maintaining reliability across varying engine conditions without excessive complexity
Solution Approach 2:
The system performs preliminary detection of cylinder bank deactivation events and pre-applies cooldown corrections before temperature estimates become unreliable. By anticipating the deactivation/reactivation cycles and preparing correction factors in advance, the system maintains accurate temperature estimation during transitions without requiring complex real-time adjustments
2Device complexity
If existing temperature models are used without deactivation detection, then the model remains simple, but OBD measures and O2 sensor evaluations become inaccurate during cylinder bank deactivation cycles
Solution Approach 1:
The system incorporates feedback by continuously monitoring cylinder bank deactivation status and using this information to adjust temperature estimates. The deactivation detection mechanism provides feedback signals that trigger corrected estimation routines, ensuring OBD measures and sensor evaluations remain accurate during deactivation cycles while adding minimal complexity to the overall model
Data Source
AI summary
A method of estimating temperature of a catalyst associated with a cylinder bank of a multi-displacement internal combustion engine having multiple cylinder banks associated with multiple catalysts. A temperature estimate of the catalysts associated with the multiple cylinder banks is set substantially equal to a base model temperature. Deactivation of a cylinder bank of the multiple cylinder banks is determined, and a catalyst cooldown correction is identified for the catalyst associated with the deactivated cylinder bank from a catalyst cooldown model including time elapsed since deactivation of the cylinder bank. The catalyst cooldown correction is applied to the temperature estimate of the catalyst associated with the deactivated cylinder bank to update the temperature estimate of the catalyst.