Drive Shaft Speed Prediction for Starter Pinion Engagement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for determining the rotational speed of a drive shaft in an internal combustion engine struggle to accurately predict speed profiles below 30 revolutions per minute, leading to unpredictable and unreliable engagement of the starter pinion during reverse oscillation, especially immediately before zero crossings.
Innovation Solution
A method that calculates the gradient of speed changes to predict theoretical speed points, allowing for reliable decision-making on engaging the starter pinion, particularly when the drive shaft rotates in the opposite direction and speed is negative, ensuring engagement during favorable speed sections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If existing methods are used to determine rotational speed below 30 rpm, then the speed profile can be forecast, but the prediction becomes unreliable and unpredictable during reverse oscillation and zero crossings
Solution Approach 1:
The method applies different evaluation criteria to different sections of the speed curve. It identifies favorable sections where tracking is meaningful and unfavorable sections where predictions are unreliable, applying local quality assessment to determine engagement suitability at each point in the oscillation cycle
Solution Approach 2:
The method performs preliminary evaluation of speed curve sections to identify favorable engagement opportunities before they occur. By analyzing the speed profile in advance and identifying favorable sections, the system can prepare for timely pinion engagement rather than reacting to unpredictable conditions
2Loss of time
If the starter pinion is engaged immediately after calculation ends, then quick engagement is achieved, but the engagement may occur at unfavorable times during unpredictable speed sections
Solution Approach 1:
The method performs preliminary identification of favorable speed curve sections in advance, creating a list of suitable engagement opportunities. This allows the system to engage the pinion quickly when conditions are favorable without risking engagement during unpredictable speed sections
Solution Approach 2:
The method continuously monitors the actual speed curve against the forecasted profile, comparing predicted behavior with actual measurements. This feedback mechanism allows the system to identify when actual conditions diverge from predictions, signaling unfavorable engagement conditions and preventing premature or mistimed engagement
3Productivity
If tracking is performed during all speed sections, then complete coverage is achieved, but meaningless tracking occurs during unfavorable sections with difficult or unpredictable speed changes
Solution Approach 1:
The method applies quality differentiation to tracking operations, identifying favorable sections where tracking produces meaningful results and unfavorable sections where tracking is pointless or misleading. This selective approach improves overall system effectiveness by focusing computational resources on productive tracking operations
Solution Approach 2:
The method extracts and isolates the favorable sections from the complete speed curve, separating useful tracking opportunities from unfavorable ones. By taking out only the favorable sections for engagement consideration, the system eliminates meaningless tracking during unpredictable speed changes while maintaining complete monitoring coverage
Data Source
Figure 1
Figure 2
AI summary
Method for predicting a rotational speed (n) of a drive shaft (16) in an internal combustion engine (13), wherein a past rotational speed (n) of the drive shaft (16) is determined, characterised in that in order to determine a theoretical rotational speed (nT1, nT2) of the drive shaft (16) at a future point in time (tT1, tT2), the change in the rotational speed (n) between two past events (P01, P11; P02, P12) occurring at different times is used, one rotational speed (n01, n11; n02, n12) and one point in time (t01, t11; t02, t12) being assigned to each event, wherein one point in time (t01, t02) is an earlier point in time and the other is a later point in time (t02, t12), which therefore lies before the predicted point in time (tT1, tT2), wherein a gradient (m) is determined for a period between the two events (P01, P11; P02, P12) and is used as the basis for deducing a theoretical future rotational speed (nT1, nT2) at the future point in time (tT1, tT2), such that in order to determine the theoretical rotational speed (nT1, nT2) of the drive shaft (16) at the future point in time (tT1, tT2), the determined gradient (m) is used to determine the theoretical rotational speed (nT1, nT2) at the future point in time (tT1, tT2), on the basis of the later point in time (t02, t12), thus determining whether the theoretical rotational speed (nT1, nT2) actually occurred before the future point in time (tT1, tT2) or not until afterwards.