Vehicle Brake Hold Control for Open-Door Stop Conditions
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Solution Overview
Problem
Motor vehicles may continue to move when insufficient braking force is applied, particularly when the engine idles or electric motor is engaged, leading to unintended movement when stationary conditions are desired.
Innovation Solution
A brake system with a controller that senses vehicle speed, door positions, and driver inputs to apply braking force when the vehicle is stationary and doors are open, releasing the brake upon accelerator input.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the vehicle is equipped with a manual brake pedal system, then the driver has direct control over braking force, but the vehicle cannot maintain stationary position when insufficient braking force is applied and the engine idles or electric motor is engaged
Solution Approach 1:
The controller proactively applies braking force when it detects that the vehicle is in a stopped state with doors open, before the vehicle can move due to engine idle or electric motor engagement. This preliminary action prevents the harmful effect of unintended movement by anticipating the potential motion caused by powertrain forces.
Solution Approach 2:
The system continuously monitors vehicle speed, door sensor status, and brake pedal force to determine when automatic braking should be applied. The controller receives feedback from these sensors and adjusts brake application accordingly, creating a closed-loop control system that maintains stationary position when needed.
2Reliability
If the brake system applies automatic braking when the vehicle is stopped with doors open, then the vehicle remains stationary, but the driver cannot easily accelerate when needed
Solution Approach 1:
The controller releases the automatically applied brake before the vehicle begins to move, in response to accelerator input. This preliminary release ensures smooth acceleration without brake drag, while still maintaining stationary position control when the vehicle is truly stopped and doors are open.
Solution Approach 2:
The brake control system dynamically adjusts its behavior based on real-time conditions: it applies brake when vehicle is stopped with doors open, and releases brake when accelerator is pressed or vehicle moves. This dynamic response allows the system to maintain reliability when needed while preserving ease of operation when the driver intends to move.
Data Source
AI summary
A motor vehicle comprising a brake system having a brake pedal actuated by a driver to apply braking force to the motor vehicle, a brake pedal sensor sensing an actuation force to the brake pedal, a vehicle speed sensor sensing speed of the motor vehicle, an accelerator input, one or more doors, one or more door sensors configured to sense an open or closed position of the one or more doors, and a controller configured to determine when the vehicle speed indicates the motor vehicle is in a stopped state and in a drive mode with at least one of the one or more doors sensed in the open position. The vehicle is held stationary from unintentional movements until all conditions are met to enable motion.