Throttle Valve Control for Particulate Filter Temperature
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Solution Overview
Problem
Existing methods for deceleration fuel shut-off (DFSO) in engines lead to particulate filter overheating due to increased oxygen delivery, which can cause filter degradation and engine issues, such as low intake manifold pressure potentially drawing lubricants into the combustion chamber.
Innovation Solution
A method that involves fully closing the throttle valve when the particulate filter reaches a threshold temperature during DFSO and adjusting the throttle position based on filter temperature to maintain the intake manifold pressure above a threshold, while increasing valve overlap to control airflow and prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If deceleration fuel shut-off is implemented to improve fuel economy, then fuel consumption is reduced, but particulate filter temperature increases causing filter degradation
Solution Approach 1:
The system continuously monitors particulate filter temperature and uses this feedback to dynamically adjust throttle valve position. When filter temperature exceeds a threshold during DFSO, the controller opens the throttle valve to increase airflow and reduce filter temperature, thereby resolving the contradiction between fuel economy and filter temperature control
Solution Approach 2:
The throttle valve position is dynamically adjusted based on real-time filter temperature conditions rather than remaining fixed. The system transitions between closed and open throttle states depending on whether filter temperature exceeds the threshold, enabling adaptive control that resolves the temperature-fuel economy contradiction
2Temperature
If throttle valve is fully closed to reduce oxygen flow to particle filter, then filter temperature is controlled, but intake manifold pressure drops causing engine degradation
Solution Approach 1:
The system monitors both filter temperature and intake manifold pressure simultaneously. When filter temperature exceeds the threshold, the controller opens the throttle valve, which increases intake manifold pressure back to normal levels while still providing some oxygen restriction to control filter temperature
Solution Approach 2:
The throttle valve position dynamically responds to filter temperature conditions. When temperature is below threshold, throttle remains closed for maximum DFSO benefit; when temperature exceeds threshold, throttle opens to restore manifold pressure, thus dynamically resolving the pressure-temperature contradiction
3Reliability
If throttle valve position is adjusted to control filter temperature, then filter degradation is prevented, but DFSO duration is limited
Solution Approach 1:
Continuous temperature monitoring with feedback control allows the system to extend DFSO duration by opening the throttle valve only when and if filter temperature exceeds the threshold. This prevents filter degradation while maximizing DFSO duration by maintaining closed throttle position during acceptable temperature conditions
Solution Approach 2:
The system changes the throttle valve opening parameter in response to filter temperature conditions, allowing DFSO to continue longer than would be possible with a fixed closed throttle position. The parameter change (throttle opening) occurs only when necessary to protect the filter, thereby extending overall DFSO duration
Data Source
AI summary
Methods and systems are provided for controlling particulate filter temperature during non-combustion conditions. In one example, a method for an engine includes responsive to a particulate filter temperature above a threshold temperature and while operating the engine with deceleration fuel shut-off (DFSO), fully closing a throttle valve configured to regulate flow of intake air to the engine, and responsive to intake manifold pressure dropping below a threshold pressure while the throttle valve is fully closed, adjusting a position of the throttle valve based on the particulate filter temperature.