Crank Angle Sensor Backward Rotation Detection for Engine Control
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Solution Overview
Problem
Existing engine control systems face issues with erroneous detection of the crank position reference part due to fluctuations in crankshaft rotation speed and backward rotation, leading to inaccurate crank angle determination and compromised fuel injection or ignition control during engine restart.
Innovation Solution
A control device with a crank angle sensor that includes a backward rotation detecting function, which outputs distinct signals for forward and backward rotations, and a control part that disallows detection of the crank position reference part during stop requests or backward rotation, using previously detected crank angles to ensure accurate engine control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the crank position reference part is detected based on the time interval of crank angle signals during engine stop or backward rotation, then the detection may capture actual position changes, but erroneous detection occurs due to fluctuation in rotation speed or backward rotation
Solution Approach 1:
The control part applies preliminary anti-action by disallowing detection of the crank position reference part when a stop request is generated or when backward rotation is detected. This preventive measure blocks the detection function before erroneous detection can occur, ensuring that the crank position reference part is only detected during normal forward rotation when the detection is reliable.
Solution Approach 2:
The control part performs preliminary action by determining the rotation direction of the crank shaft before attempting to detect the crank position reference part. By checking whether the crank shaft is rotating forward or backward in advance, the system can conditionally enable or disable detection, thereby preventing erroneous detection during backward rotation or stop conditions.
2Ease of operation
If the engine restart control uses stored engine stopping position information, then cylinder discrimination can be performed, but inaccurate crank angle determination occurs when rotation speed fluctuates
Solution Approach 1:
The control part dynamically adjusts the detection of the crank position reference part based on the current operating condition. By changing the detection state from enabled to disabled according to rotation direction and stop request status, the system adapts to varying operational conditions, ensuring accurate crank angle determination only when detection conditions are favorable.
Solution Approach 2:
The control part uses feedback from the crank angle sensor and rotation direction determination to control the detection process. By continuously monitoring the crank angle signals and rotation direction, the system provides feedback to the detection function, enabling it to adjust its operation and prevent erroneous detection based on real-time condition assessment.
Data Source
AI summary
A crank angle sensor that outputs a crank angle signal at a predetermined crank angle by synchronizing rotation of a signal rotor fixed on a crank shaft of an internal combustion engine, an interval of the crank angle signals being longer at a specific crank angle corresponding to a position of a crank position reference part of the signal rotor, includes a backward rotation detecting function that outputs different crank angle signals in a forward rotation of the crank shaft and in a backward rotation of the crank shaft, and a control part disallows the detection of the crank position reference part when a stop request to the internal combustion engine is generated or when the backward rotation of the crank shaft is detected based on the crank angle signal, and controls the internal combustion engine by calculating the crank angle based on the crank angle of the crank position reference part detected before the detection of the crank position reference part is disallowed and the crank angle signal.