Alternator Starter Belt Failure Detection via Speed Monitoring
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Solution Overview
Problem
Existing methods for detecting belt failures connecting an alternator-starter to a heat engine in hybrid vehicles are inadequate, as they fail to differentiate between slipping and broken belts, leading to false detections and safety issues during frequent stops and restarts.
Innovation Solution
A method that measures the alternator-starter speed and applies a zero generator torque to diagnose belt conditions, distinguishing between broken and slipping belts by predefined speed thresholds and durations, thereby reducing false detections and ensuring safe engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing methods compare engine and alternator speeds during start-up to detect belt breakage, then broken belt detection is achieved, but false detections occur during hybrid vehicle operation with frequent stops and restarts
Solution Approach 1:
The patent applies preliminary action by measuring alternator speed continuously during engine operation (not just during start-up) and comparing it with engine speed to detect belt failures before they cause critical issues. The control unit continuously monitors the alternator speed via sensor and compares it with the measured engine speed to identify when the alternator stops rotating while the engine continues running, indicating belt breakage.
Solution Approach 2:
The patent implements feedback by using the alternator speed sensor to continuously provide speed information to the control unit, which compares this feedback with engine speed and triggers appropriate responses (engine shutdown or warning signal) when belt failure is detected. This closed-loop feedback system enables reliable detection without requiring complex additional hardware.
2Object-affected harmful factors
If the engine is shut down when belt failure is detected to ensure safety, then driver safety is improved, but unnecessary shutdowns occur due to false detections from wet or slipping belts
Solution Approach 1:
The patent applies preliminary action by continuously monitoring alternator speed during engine operation and detecting belt failures before they compromise safety. By measuring alternator speed via sensor and comparing it with engine speed in advance, the system can identify when the alternator stops rotating while the engine continues running, triggering appropriate safety responses before critical failure occurs.
Solution Approach 2:
The patent uses parameter changes by monitoring the alternator speed parameter and comparing it with engine speed to detect when the alternator stops rotating. The control unit analyzes changes in this speed parameter over time and triggers different responses (shutdown or warning) based on the detected pattern, thereby distinguishing between actual belt failures and temporary slippage conditions.
3Ease of operation
If existing methods only detect belt breakage during engine start-up, then detection simplicity is maintained, but detection coverage is insufficient for hybrid vehicles with frequent stops and restarts
Solution Approach 1:
The patent applies preliminary action by measuring alternator speed continuously during engine operation (not just during start-up) and comparing it with engine speed to detect belt failures before they cause critical issues. The control unit continuously monitors the alternator speed via sensor and compares it with the measured engine speed to identify when the alternator stops rotating while the engine continues running, indicating belt breakage.
Solution Approach 2:
The patent implements universality by using the existing alternator speed sensor and control unit to perform both normal alternator function monitoring and belt failure detection. The same control unit that manages engine operation also detects belt failures by comparing alternator and engine speeds, eliminating the need for separate detection hardware and maintaining simplicity while expanding detection coverage to all operating conditions.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively differentiates between broken and slipping belts, reducing the risk of false detections and ensuring safe engine operation by temporarily prohibiting engine stops for slipping belts and permanently for broken belts, enhancing driver safety and reducing unnecessary vehicle repairs.
Implementation Method 1
the alternator-starter shaft pulley can slip on the belt, and the alternator-starter fails to provide an assisted start
Data Source
Figure 1
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AI summary
The invention relates to a method for detecting a failure of a belt connecting an alternator starter to a heat engine, which comprises: measuring or estimating the operating speed of the alternator starter when the engine is rotating (MTH tour) at an engine speed (Nm) comprised between two predefined thresholds and if the operating speed of the alternator starter (Na, Nb) is actually lower than a first predefined operating speed value (Nd1) at least during a first predetermined time (td1), the belt is detected as being potentially broken; then, a generating torque (Cg) of zero is applied to the alternator starter, and if the operating speed of the alternator starter (Na, Nb) is actually lower than a second predefined operating speed value (Nd2) during a second predefined time (td2), the belt is confirmed as being broken or in the case that the second predefined operating speed value (Nd2) is reached before the end of the second predefined time (td2), the belt is considered to be slipping but not broken.