Engine Control Apparatus for Fuel Cutoff Filter Overheating
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Solution Overview
Problem
Existing control apparatuses for internal combustion engines may cause the filter to overheat during repeated fuel cutoff processes due to residual oxygen, especially when the integrated amount of intake air is smaller than the predetermined value, leading to premature cancellation of the fuel cutoff process.
Innovation Solution
A control apparatus that adjusts the first and second predetermined values based on the integrated amount of intake air and elapsed time since the last fuel cutoff process, with a higher speed of increase in the first index value when the second index value is small, to ensure appropriate cancellation timing and prevent filter overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the fuel cutoff process is performed repeatedly without sufficient time interval, then the filter may be overheated due to residual oxygen, but cancelling the process early reduces regeneration efficiency
Solution Approach 1:
The patent applies dynamics by making the first predetermined value variable rather than fixed. The control apparatus adjusts the first predetermined value based on the second index value (elapsed time since last fuel cutoff), allowing the cancellation threshold to adapt dynamically to the actual time interval between operations. This resolves the contradiction by enabling the system to tolerate longer integration periods when sufficient time has passed (reducing overheating risk) while maintaining stricter limits when time intervals are short (preventing overheating), thereby maintaining regeneration reliability across varying operating conditions.
Solution Approach 2:
The patent applies parameter changes by modifying the first predetermined value based on the second index value. When the elapsed time since the last fuel cutoff is short, the first predetermined value is set to a smaller threshold, causing earlier cancellation. When sufficient time has passed, the threshold increases, allowing more extensive regeneration. This parameter adaptation resolves the technical contradiction by adjusting the operational threshold according to thermal history, preventing filter overheating while ensuring reliable regeneration when conditions permit.
2Temperature
If the first predetermined value is set low to prevent overheating, then the fuel cutoff process is cancelled early, but this reduces the amount of oxygen supplied for regeneration
Solution Approach 1:
The patent resolves this contradiction through dynamic adjustment of the first predetermined value based on the second index value (elapsed time). Rather than using a uniformly low threshold that would always limit oxygen supply, the system dynamically sets the threshold: lower when time intervals are short (prioritizing temperature control) and higher when time intervals are sufficient (prioritizing regeneration efficiency). This dynamic approach allows the system to maximize oxygen supply and regeneration effectiveness whenever thermal conditions permit, while still preventing overheating when time constraints exist.
Solution Approach 2:
The patent applies parameter changes by making the first predetermined value dependent on the second index value. This causes the oxygen supply threshold to change based on thermal history: stricter limits are applied when the filter may still be hot from previous operations, while more permissive limits are applied when sufficient cooling time has elapsed. This resolves the contradiction by allowing maximum oxygen supply (and thus maximum regeneration) whenever temperature conditions allow, while preventing overheating when time intervals are insufficient.
3Reliability
If the fuel cutoff process is cancelled based on integrated intake air amount, then regeneration is controlled, but residual oxygen from previous processes causes overheating when time interval is short
Solution Approach 1:
The patent applies feedback by using the second index value (elapsed time since last fuel cutoff) as input to adjust the first predetermined value. This creates a feedback loop where the system monitors the time interval between operations and adjusts the cancellation threshold accordingly. When the feedback indicates short time intervals, the threshold is lowered to prevent overheating from residual oxygen. When feedback shows sufficient time has passed, the threshold increases to allow more extensive regeneration. This feedback mechanism resolves the contradiction by making regeneration control adaptive to thermal conditions rather than relying on fixed thresholds.
Solution Approach 2:
The patent applies preliminary action by using the second index value to predict potential overheating risks before they occur. By monitoring the elapsed time since the last fuel cutoff and adjusting the first predetermined value in advance, the system proactively prevents overheating rather than reacting to it after it occurs. This preliminary adjustment of the cancellation threshold based on time interval ensures that residual oxygen from previous processes does not cause overheating, while still allowing effective regeneration when conditions are safe.
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 approach effectively prevents filter overheating by adjusting the fuel cutoff process timing according to the residual oxygen levels, ensuring the filter is not subjected to excessive oxygen during subsequent fuel cutoffs, even when the integrated air amount is insufficient.
Implementation Method 1
a filter located in the exhaust passage to collect particulate matter contained in exhaust gas
Implementation Method 2
the filter is regenerated through combustion of the particulate matter deposited in the filter
Data Source
AI summary
A control apparatus for an internal combustion engine performs a first acquisition process for acquiring a first index value corresponding to an integrated amount of intake air during a performance of the fuel cutoff process, and a cancellation process for cancelling the fuel cutoff process when the first index value becomes equal to or larger than a first predetermined value during the performance of the fuel cutoff process. Besides, the control apparatus performs a second acquisition process for acquiring a second index value corresponding to an elapsed time from the end of the fuel cutoff process to the subsequent start of the fuel cutoff process, and a change process for making the first predetermined value smaller when the second index value is small in starting the fuel cutoff process than when the second index value is large in starting the fuel cutoff process.