EV Thermal LIN Shutdown Control for Ignition-Off Battery Drain
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Solution Overview
Problem
Thermal system components in electrified vehicles consume significant energy during ignition-off states, leading to energy drainage from the low voltage battery and causing issues like insufficient engine cranking and high voltage system contactor welding, which is confusing and annoying for customers.
Innovation Solution
A supervisory controller manages thermal systems via a LIN bus to transmit timing instructions, ensuring completion of functions within a calibratable period and subsequent shutdown, avoiding unnecessary energy drainage and communication delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If thermal system components are activated during ignition-off states, then thermal regulation function is maintained, but energy drainage from low voltage battery increases significantly
Solution Approach 1:
The supervisory controller sends a shutdown command to thermal system components before the LIN bus is turned off. This preliminary action ensures that components complete their current thermal regulation cycle and shut down gracefully, preventing energy drainage while maintaining thermal function until the appropriate moment
Solution Approach 2:
The system implements periodic shutdown commands to thermal components during ignition-off states. The supervisory controller monitors thermal system status and sends periodic shutdown requests to ensure components remain off during idle periods, reducing energy consumption while maintaining the ability to reactivate when needed
2Loss of energy
If LIN bus is shutdown immediately during ignition-off, then energy consumption is reduced, but communication delay or malfunction may occur causing thermal systems to remain active
Solution Approach 1:
The supervisory controller sends shutdown commands to thermal system components before the LIN bus is turned off. This preliminary action ensures that components receive the shutdown instruction while the communication bus is still active, preventing communication delays or malfunctions that would occur if the bus were shut down first
Solution Approach 2:
The system provides a buffer period between sending shutdown commands and actually shutting down the LIN bus. This cushioning time allows thermal components to acknowledge and execute shutdown commands reliably, preventing malfunction or unintended operation while still achieving energy savings
3Device complexity
If thermal system components remain active after LIN bus shutdown, then communication simplicity is maintained, but unexpected operation and customer confusion occur
Solution Approach 1:
The supervisory controller sends shutdown commands to thermal system components before the LIN bus is turned off. This preliminary action ensures that components complete their current thermal regulation cycle and shut down gracefully, preventing energy drainage while maintaining thermal function until the appropriate moment
Solution Approach 2:
The system implements a feedback mechanism where thermal system components acknowledge receipt of shutdown commands and confirm their status to the supervisory controller. This feedback loop ensures that components have properly shut down before the LIN bus is turned off, preventing unexpected operation and customer confusion
Data Source
AI summary
A control and thermal management method for an electrified vehicle includes, in response to a valid wakeup request, transmitting, by a supervisory controller and via a local interconnect (LIN) bus, timing instructions for operation of a set of thermal systems powered by low voltage battery, in response to an ignition-off request, commanding, by the supervisory controller and via the LIN bus, a request for the set of thermal systems to complete their existing functions within a calibratable period, and in response to a function completion confirmation from the set of thermal systems, commanding, by the supervisory controller, the LIN bus and the set of thermal systems to shutdown, thereby avoiding a communication delay or a malfunction that could result in the set of thermal systems remaining active after the LIN bus is shutdown.