Engine Speed Control Noise Removal Unit
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Solution Overview
Problem
Existing engine rotational speed control systems experience hunting due to slight variations in target rotational speed caused by errors in AD conversion and signal noise, which are not effectively removed by averaging processes.
Innovation Solution
An engine rotational speed control device incorporating a noise removal processing unit, a moving average unit, and a dead zone processing unit to correct command values by setting output values based on predetermined conditions, such as successive steps and signal duration, to eliminate unintended variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If digital conversion is performed on analog target rotational speed input, then the target rotational speed can be controlled in discrete steps, but slight variations and noise cause hunting around switching rotational speeds
Solution Approach 1:
The noise removal processing unit performs preliminary correction of the command value before it is used for fuel injection control. By detecting and removing noise in advance (before the control action), the system prevents hunting around switching rotational speeds while maintaining automatic control functionality.
Solution Approach 2:
The system continuously monitors the command value for variations exceeding a threshold and applies corrective action when noise is detected. This feedback mechanism compares the current command value with previous values and adjusts accordingly to maintain stable engine operation.
2Stability of the object's composition
If averaging process is applied to command value, then instantaneous variation is reduced, but slight systematic variation cannot be removed
Solution Approach 1:
The noise removal processing unit extracts and removes only the noisy components from the command value while preserving the genuine target rotational speed signal. By selectively removing variations exceeding the threshold (noise) while maintaining systematic variations below the threshold (genuine signals), the system achieves both smoothness and precision.
Solution Approach 2:
The system changes the parameter of the command value by applying threshold-based filtering. When variations exceed the predetermined threshold, the command value is corrected to remove noise; when variations are within the threshold, the original value is maintained. This dynamic parameter adjustment achieves both smoothing and precision preservation.
Data Source
AI summary
An engine rotational speed control device (4) includes a noise removal processing unit (6) which corrects a command value, wherein the noise removal processing unit (6) is configured to set a current first output value (B(i)) to be identical to a previous first output value (B(i−1)) in a case where, in a latest step group, the number of successive increase steps is smaller than a first predetermined number (n) and the number of successive decrease steps is smaller than the first predetermined number (n), the increase step is a step in which a current first input value (A(i)) is greater than the previous first output value (B(i−1)) by a first set width (n) or more, and the decrease step is a step in which the current first input value (A(i)) is smaller than the previous first output value (B(i)) by the first set width (n) or more.