Engine Controller Catalyst Temperature Management During Misfire
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Solution Overview
Problem
Existing internal combustion engine controllers face challenges in preventing excessive temperature increases of catalysts during misfire events, as the current temperature-increasing processes can lead to overheating due to increased fuel supply, which is not effectively mitigated.
Innovation Solution
A controller that executes a decreasing process by suspending fuel deactivation in some cylinders, starting fuel supply to them, and adjusting air-fuel ratios to leaner conditions, reducing the number of cylinders with deactivated fuel supply, and decreasing fuel amounts to prevent excessive catalyst temperature increases during misfires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fuel supply is deactivated to one or some cylinders and supplied to remaining cylinders to increase catalyst temperature, then the catalyst temperature increases, but the occurrence of misfire increases the amount of fuel supplied to the catalyst causing excessive temperature increase
Solution Approach 1:
The controller dynamically adjusts the fuel supply strategy based on real-time misfire detection. When misfires are detected, the system transitions from a static fuel deactivation pattern to a dynamic adjustment where fuel supply is modified in response to actual combustion conditions, preventing excessive catalyst temperature increase while maintaining temperature-increasing process effectiveness
Solution Approach 2:
The system implements feedback control by detecting misfires and using this information to adjust fuel supply to cylinders. The misfire detection mechanism provides real-time feedback to the controller, which then modifies the fuel injection strategy to prevent excessive fuel accumulation in the catalyst while maintaining the temperature-increasing objective
2Temperature
If fuel supply is increased to remaining cylinders during temperature-increasing process, then catalyst temperature increases, but misfire causes unburned fuel to increase excessively in exhaust gas
Solution Approach 1:
The controller applies different fuel supply strategies to different cylinders based on their individual misfire conditions. Cylinders experiencing misfires receive adjusted fuel supply compared to cylinders operating normally, creating local quality differences in fuel injection that prevent excessive unburned fuel accumulation in the exhaust system while maintaining overall temperature-increasing effectiveness
Solution Approach 2:
Instead of completely deactivating fuel supply to all cylinders or maintaining full supply, the system applies partial fuel supply adjustments. This partial action approach selectively modifies fuel injection to prevent excessive unburned fuel in exhaust while maintaining sufficient fuel supply to achieve the temperature-increasing process objective
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 temperature increase of the catalyst, preventing overheating by managing fuel and air supply, even during misfire events, thereby maintaining optimal engine performance and catalyst health.
Implementation Method 1
The exhaust passage includes a catalyst that purifies exhaust gas
Implementation Method 2
The internal combustion engine includes an exhaust passage and cylinders
Data Source
AI summary
A controller for an internal combustion engine is configured to execute a temperature-increasing process, a misfire detecting process that detects a misfire, a determining process, and a decreasing process. The temperature-increasing process includes increasing a temperature of a catalyst through a partial cylinder fuel cut-off process. The determining process includes determining whether a number of misfires detected by the misfire detecting process in a number of times combustion control has been executed in each of cylinders is greater than or equal to a given value. The decreasing process includes setting an amount of temperature increase in the catalyst to be smaller when the number of misfires is greater than or equal to the given value than when the number of misfires is less than the given value.