Crankshaft Acceleration Detection for Engine Compression Loss
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Solution Overview
Problem
Existing methods for detecting compression loss in internal combustion engines often lead to mistaken determinations during engine startup, as they rely solely on the reduction in crankshaft speed, which can be influenced by factors other than compression loss, resulting in continuous false positives.
Innovation Solution
A control apparatus with an electronic control unit that determines crankshaft acceleration at compression TDC and prohibits compression loss determination if acceleration occurs consecutively in multiple cylinders, using threshold values and counters to differentiate between actual and mistaken compression loss scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If compression loss determination is carried out simply on the basis of the amount of reduction in the speed of rotation of the crank shaft, then the determination process is simple, but mistaken determination occurs continuously during engine startup
Solution Approach 1:
The system performs preliminary assessment by counting consecutive acceleration occurrences before allowing compression loss determination. When acceleration occurs a first specific number of times consecutively, the system prohibits determination in advance, preventing mistaken determinations during startup conditions before they can occur continuously.
Solution Approach 2:
The system uses feedback from detected acceleration events to dynamically control the determination process. By monitoring whether acceleration occurs consecutively and adjusting the permission status accordingly, the system adapts its determination behavior based on real-time engine conditions, preventing false positives during transient states.
2Reliability
If compression loss determination is prohibited when acceleration occurs consecutively, then mistaken determination is suppressed, but determination opportunity is reduced
Solution Approach 1:
The system dynamically adjusts the determination permission status based on real-time acceleration patterns. The prohibition is not fixed but changes according to whether consecutive acceleration events are detected, allowing the system to be restrictive when needed and permissive when safe, optimizing both accuracy and determination opportunities.
Solution Approach 2:
The system changes the operational parameter of determination permission based on the count of consecutive acceleration events. When the count reaches a first specific number, the parameter switches from permitted to prohibited. This parameter change mechanism allows flexible control that balances reliability improvement against loss of determination opportunities.
Data Source
AI summary
A control apparatus for an internal combustion engine, the internal combustion engine including a plurality of cylinders, and the control apparatus including: an electronic control unit configured to: a) determine whether or not acceleration of a crank shaft at compression top dead center is equal to or greater than a threshold value; b) determine that a compression loss has occurred in the cylinder, when the acceleration of the crank shaft is equal to or greater than the threshold value; and c) prohibit the determination of compression loss, when acceleration of rotation of the crank shaft at compression top dead center has occurred a first specific number of times consecutively in the plurality of cylinders.