Relay Sticking Detection in Vehicle Starter Control Lines
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Solution Overview
Problem
Existing methods for detecting sticking relays in a pair of electrical relays used in internal combustion engine starters fail to differentiate between temporary and permanent sticking, and do not provide effective management strategies for stuck relays, particularly in the context of automatic stop and start systems in vehicles.
Innovation Solution
A method involving measurement of a physical quantity representative of the control voltage between the start of the authorization and control signals, with alternation of these signals between the relays during the same current phase to detect sticking, and subsequent confirmation or invalidation of the sticking state through additional diagnostics during subsequent driving phases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If relay sticking detection is performed using existing methods, then relay faults can be detected, but the methods fail to differentiate between temporary and permanent sticking states
Solution Approach 1:
The patent applies preliminary action by performing a first detection of relay sticking before the relay is actuated, and then performing a second detection after the relay has been actuated one or more times. This sequential detection approach allows the system to compare the relay's state before and after actuation to determine whether the sticking is temporary or permanent, thereby differentiating between the two states without requiring additional sensors or complex measurement systems.
2Reliability
If no detection method is implemented, then the system remains simple, but unwanted starts and potential damage can occur due to undetected stuck relays
Solution Approach 1:
The patent applies self-service by utilizing the relay's own actuation process and existing control unit to perform the detection. The control unit already responsible for controlling the relay is also used to detect sticking by measuring whether the relay contacts remain closed after they should open. This approach enables reliable detection without adding separate dedicated detection hardware, thereby minimizing the increase in device complexity while improving starter system reliability.
3Ease of operation
If relay sticking is not detected and managed, then the system operates without additional controls, but stuck relays can cause unwanted starts and potential damage
Solution Approach 1:
The patent applies feedback by continuously monitoring the relay's contact state after actuation and using this information to determine whether the relay is stuck. The control unit receives feedback from the detection process and adjusts its operation accordingly - preventing unwanted starts by identifying stuck relays and managing them appropriately. This feedback mechanism enables the system to respond to relay sticking conditions and prevent harmful effects without requiring manual intervention or complex additional controls.
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
Enables simple and effective detection of stuck relays, preventing unwanted starts and potential damage by identifying and managing stuck relays before they cause issues, thereby ensuring reliable operation of the starter system.
Implementation Method 1
Each relay 1, 2 respectively comprises a winding 1a, 2a, and a contactor 1b, 2b disposed on line 11 of secondary power supply. When the winding 1a (respectively 1b) is not electrically supplied the contactor 2a (respectively) 2b is open. The electrical supply of the solenoid 1a, (respectively) 2a, operates the closing of the contactor 2a, (respectively) 2b.
Implementation Method 2
These solenoids 6, 6a mainly perform two functions as electromagnetic relays when they are electrically powered. The first function is the closing of a contactor 8 allowing the electrical supply of the electric motor 7 of the starter 10 by the electrical supply line 12.
Data Source
Figure 1a~1b
Figure 2
Figure 3
AI summary
The invention relates to a method for detecting the sticking of one of two electric relays (1, 2) arranged in series in a control line (11) supplying a control voltage for an internal combustion engine starter (10) equipping a motor vehicle, an electric motor (7) of the starter (10) being powered when both relays (1, 2) are closed, each by a separate signal, one of the two signals being a signal referred to as the authorization signal (auto) beginning before and ending after the other signal, referred to as the control signal (com). According to the invention, a physical value representative of the control voltage is measured, and the sticking of the relay that received the control signal (com) is detected when, based on the measurement, it is determined that the control voltage is not zero between the start of the authorization signal (auto) and the start of the control signal (com).