Single-Wire Actuator Heartbeat Signal Diagnostics
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional diagnostic systems for single-wire actuators in hybrid and electric vehicles are insufficient in detecting operating conditions, particularly an open ground condition, leading to potential miscommunication between the actuator and controller, which can result in ineffective heating systems when engine waste heat is insufficient.
Innovation Solution
A system and method where the auxiliary pump transmits a heartbeat signal when connected to a power source and ground terminal, allowing the controller to store a diagnostic code if the signal is not received within a predetermined time, enabling detection of actuator functionality and initiating corrective actions such as starting the engine or activating indicators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-wire actuator interface is used to reduce complexity and cost, then device complexity is reduced, but the ability to detect open ground conditions and communicate actuator status is lost
Solution Approach 1:
The actuator is configured to provide feedback signals to the controller through the single-wire interface. The feedback signal includes a heartbeat portion indicating actuator power status and a diagnostic portion indicating actuator ground status, enabling the controller to monitor actuator functionality without additional wiring complexity.
Solution Approach 2:
The single-wire interface performs multiple functions: it provides control signals from the controller to the actuator, transmits heartbeat status information, communicates diagnostic information about open ground conditions, and enables bidirectional communication all through one wire, eliminating the need for separate control and status wires.
2Measurement precision
If integrated actuator diagnostics are implemented, then measurement precision is improved, but the timing and sufficiency of feedback for specific applications remains insufficient
Solution Approach 1:
The actuator performs self-diagnostics and generates heartbeat and diagnostic signals during normal operation before actual failures occur. This continuous preliminary monitoring ensures that open ground conditions are detected immediately when they occur, rather than waiting for periodic external diagnostic checks.
Solution Approach 2:
The actuator autonomously monitors its own operational status and ground connection integrity, generating appropriate feedback signals without requiring external diagnostic equipment or controller intervention. This self-service capability ensures continuous monitoring and immediate detection of faults.
3Ease of operation
If the controller commands the actuator on without detecting open ground conditions, then ease of operation is maintained, but harmful effects occur due to ineffective actuator operation
Solution Approach 1:
The controller is configured to detect open ground conditions through the diagnostic portion of the feedback signal before commanding the actuator to operate. When an open ground condition is detected, the controller prevents actuator activation, thereby avoiding the harmful effect of commanding an inoperative actuator and ensuring the heating system only operates when the actuator is functional.
Data Source
AI summary
A system and method for determining functionality of a single signal wire actuator of a vehicle monitor the signal wire for a heartbeat signal after commanding the actuator and waiting for a self-diagnostic period. In one embodiment, a hybrid vehicle includes an engine, an electric heater, a heater core and a valve positioned to route coolant through an engine and/or an electric heater. An actuator positioned to circulate coolant through the electric heater and the heater core is configured to transmit a heartbeat signal while connected to a power source and a ground terminal. A vehicle controller may be configured to store a diagnostic code, start the engine and/or control the valve to selectively route coolant through the engine and the heater core in response to a heat request and the heartbeat signal not being received from the actuator within a predetermined interval of time.