Engine Speed Prediction Using Reversed Friction Component
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Solution Overview
Problem
Existing engine control systems face accuracy issues in predicting engine speed during the transition from fuel combustion stop to engine rotation stop, leading to potential mechanical noise and wear when restarting the engine, due to assumptions about energy loss components.
Innovation Solution
An engine control apparatus that calculates future engine speed by reversing the sign of the friction component of energy loss in the normal rotation range and includes a pumping loss component in the reverse rotation range, improving accuracy in predicting engine speed and reducing mechanical noise and wear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the sum of the compression component over all strokes of the engine is assumed to be zero in predicting the engine speed, then the calculation is simplified, but the accuracy in predicting the engine speed decreases with an increase in compression component
Solution Approach 1:
The loss energy is segmented into distinct components: friction component and compression component. The friction component has its sign reversed for reverse rotation prediction, while the compression component is calculated separately using pumping loss. This segmentation allows each component to be handled appropriately, improving prediction accuracy without excessive complexity.
Solution Approach 2:
The sign of the friction component is changed (reversed) when calculating loss energy for reverse rotation range. Additionally, the compression component is transformed into a pumping loss calculation. These parameter changes enable accurate prediction of engine speed in reverse rotation while maintaining manageable calculation complexity.
2Productivity
If the engine is restarted quickly without waiting for complete stop, then fuel consumption is reduced, but the pinion may fail to mesh properly with the ring gear causing noise and mechanical wear
Solution Approach 1:
The engine control apparatus performs preliminary calculation of future engine speed in the reverse rotation range using the reversed friction component and pumping loss. This preliminary action enables determination of the optimal restart timing before the engine actually restarts, ensuring the pinion meshes properly with the ring gear while achieving quick restart.
Solution Approach 2:
The system uses calculated future engine speed as feedback to determine the optimal restart timing. By continuously monitoring predicted engine speed in reverse rotation and using this information to control starter activation, the system ensures reliable meshing while maintaining fast restart capability.
Data Source
AI summary
An engine control apparatus predicts the speed of an engine in a normal rotation range as a function of a loss energy in an engine rotation pulsating period and also predicts the speed of the engine in a reverse rotation range as a function of a pumping loss component and a loss energy which is derived by reversing the sign of a value of a friction component that is a portion of the loss energy in the normal rotation range and arises from mechanical friction to which the piston is subjected during stroke thereof. The pumping loss component is an energy loss occurring in the intake stroke of the engine. This calculation enhances the accuracy in predicting a future engine speed between start of a drop in speed of the engine resulting from stop of combustion of fuel and stop of rotation of the engine.