In-Cylinder Pressure Sensor Failure Compensation
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Solution Overview
Problem
Conventional internal combustion engine control systems fail to continuously calculate combustion state parameters accurately when an in-cylinder pressure sensor fails, leading to disrupted engine and vehicle control.
Innovation Solution
A method that calculates combustion state parameters based on detection values from multiple in-cylinder pressure sensors across at least two cylinders, determining abnormality failures and using healthy sensors to maintain parameter accuracy, even when one sensor fails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the ignition timing is fixed to a predetermined value when a pressure sensor failure is detected, then the system reliability is improved through fail-safe operation, but the productivity deteriorates because the combustion state parameter calculation is stopped
Solution Approach 1:
The patent uses data from healthy cylinders (copies) to reconstruct combustion state parameters for the failed cylinder. When one pressure sensor fails, the system calculates combustion parameters for that cylinder by referencing pressure data and combustion characteristics from other functioning cylinders, thereby maintaining continuous parameter calculation without fixing the ignition timing.
Solution Approach 2:
The system dynamically changes the calculation method based on sensor status. When all sensors are healthy, direct measurement is used; when one sensor fails, the system switches to a parameter-based calculation method using data from healthy sensors, thus adapting to maintain both reliability and productivity.
2Device complexity
If the ignition timing control is stopped when a pressure sensor failure occurs, then the device complexity is reduced through simplified control logic, but the measurement precision deteriorates because continuous combustion state monitoring is lost
Solution Approach 1:
The system creates a virtual representation of the failed sensor's data by copying and adapting measurements from healthy sensors. This allows continuous monitoring of combustion state parameters with maintained precision without requiring complex redundant sensor systems or shutting down control functions.
Data Source
AI summary
A combustion state parameter calculation method for an internal combustion engine, which is capable of continuously calculating a combustion state parameter while properly maintaining the accuracy of the calculated parameter even when part of in-cylinder pressure sensors is in failure. In the combustion state parameter calculation method, as a combustion state parameter, a first combustion state parameter dependent on the magnitude of in-cylinder pressure is calculated based on a detection value from an in-cylinder pressure sensor, on a cylinder-by-cylinder basis. When it is determined that a characteristic abnormality failure in which the magnitude of the detection value deviates from the actual in-cylinder pressure has occurred in part of the in-cylinder pressure sensors and has not occurred in the other in-cylinder pressure sensors, the first combustion state parameter of a failure-determined cylinder is calculated based on the detection value from the other in-cylinder pressure sensors.