BEV Park Pawl Control With Redundant Power Failover
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Solution Overview
Problem
Conventional park pawl control systems in battery electric vehicles (BEVs) face challenges with electrical system malfunctions, leading to potential drivability issues when the park pawl system cannot be controlled, and existing solutions like additional hardware increase costs and weight, particularly problematic for lighter weight BEVs.
Innovation Solution
A park electronic securement system utilizing an electrical vehicle control unit (EVCU) with a power inverter module, a high voltage battery, a DC-DC converter for redundant power, and a low voltage battery, allowing the EVCU to command the park pawl or electric park brake to transition the BEV to a park state during electrical system malfunctions, using a redundant power source voltage when malfunctions occur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional hardware (electric motors and spring loads) is added to the park pawl system to ensure securement during electrical malfunctions, then reliability is improved, but device complexity, weight, and cost increase significantly
Solution Approach 1:
The patent makes the existing low voltage battery serve multiple functions: it powers the EVCU during normal operation and serves as a backup power source during electrical malfunctions. This eliminates the need for separate backup power hardware while maintaining reliability. The EVCU itself becomes a multi-functional component that handles both normal control and emergency securement operations.
Solution Approach 2:
The system uses its own existing components (low voltage battery and EVCU) to solve the problem of electrical malfunction. The EVCU monitors its own power status and automatically switches to backup mode when needed, and the low voltage battery automatically provides power when the high voltage system fails, without requiring external intervention or additional dedicated backup components.
2Reliability
If additional hardware (electric motors and spring loads) is added to the park pawl system to ensure securement during electrical malfunctions, then reliability is improved, but weight increases
Solution Approach 1:
The low voltage battery is designed to serve dual purposes: powering the EVCU during normal operation and providing backup power during electrical malfunctions. By making this existing component multi-functional, the patent eliminates the need for additional backup power hardware that would increase weight, while still ensuring reliable park pawl control during failures.
3Reliability
If additional hardware (electric motors and spring loads) is added to the park pawl system to ensure securement during electrical malfunctions, then reliability is improved, but cost increases significantly
Solution Approach 1:
The patent makes the existing low voltage battery and EVCU serve multiple functions, eliminating the need for additional dedicated backup hardware. This approach maintains reliability during electrical malfunctions while avoiding the significant cost increases associated with adding electric motors, spring loads, and other mechanical backup components.
4Device complexity
If the park pawl system is controlled solely by the low voltage battery and EVCU without redundant power sources, then device complexity and cost are reduced, but reliability deteriorates during electrical malfunctions
Solution Approach 1:
The low voltage battery is designed to serve dual purposes: powering the EVCU during normal operation and providing backup power during electrical malfunctions. This multi-functional design maintains reliability during failures without requiring separate backup power hardware, thus avoiding increased complexity.
Solution Approach 2:
The EVCU continuously monitors the electrical system status and automatically detects when the high voltage battery or DC-DC converter fails. When a malfunction is detected, the EVCU switches to using power from the low voltage battery to maintain park pawl control, providing automatic feedback-based failover without requiring complex manual intervention systems.
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 reliable park e-securement without additional hardware, maintaining drivability and reducing weight and cost issues, even during electrical system malfunctions, by providing a redundant power source for the EVCU to control the park pawl system.
Implementation Method 1
a DC-DC converter configured to step-down a voltage of the high voltage battery to a redundant power source voltage
Data Source
AI summary
A park electronic securement (e-securement) system for a battery electric vehicle (BEV) includes an electric vehicle control unit (EVCU) connected to a park pawl system of the BEV and configured to, when there is at least one of a plurality of malfunctions of an electrical system including a high voltage battery, a DC-DC converter, and a low voltage battery, receive power from a redundant power source voltage provided by the high voltage battery via the DC-DC converter and command either the park pawl system or an electric park brake to transition the BEV to a park state and, when there are none of the plurality of malfunctions of the electrical system, receive power from the low voltage battery for control of the park pawl system to transition the BEV to the park state when requested.