Vehicle Brake Control for Communication Abnormality
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing brake control apparatus for vehicles faces reliability issues when communication between the hybrid ECU and brake ECU becomes abnormal, leading to insufficient braking force and discomfort for occupants due to variations in deceleration.
Innovation Solution
The vehicle is configured with an electric motor, a first control unit for regeneration braking, a friction-type braking apparatus, and a second control unit, where the first control unit gradually decreases regeneration braking force and the second control unit gradually increases friction braking force in case of communication abnormalities, ensuring the actual braking force matches the target total braking force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the hybrid ECU and brake ECU communicate and cooperate to precisely generate the target total braking force, then the braking control precision is improved, but the system reliability deteriorates when communication becomes abnormal
Solution Approach 1:
The brake ECU preliminarily determines the target friction braking force based on the target total braking force before communication with the hybrid ECU. This preliminary determination ensures that when communication abnormalities occur, the brake ECU can immediately execute the pre-calculated friction braking force without waiting for communication, thereby maintaining system reliability while preserving braking control precision under normal conditions
2Speed
If the hybrid ECU immediately stops the regeneration operation when the main switch is operated, then the shutdown response speed is improved, but the braking force stability deteriorates due to rapid decrease in regeneration braking force
Solution Approach 1:
The brake ECU preliminarily determines the target friction braking force based on the target total braking force before the hybrid ECU stops the regeneration operation. When the main switch is operated, the brake ECU immediately executes the pre-determined friction braking force, which compensates for the rapid decrease in regeneration braking force. This preliminary action ensures that the total braking force remains stable during shutdown, maintaining braking force stability while preserving fast shutdown response
Solution Approach 2:
The brake ECU prepares the friction braking force in advance to cushion the rapid decrease in regeneration braking force when the main switch is operated. By having the friction braking force ready and immediately applicable, the system compensates for the sudden loss of regeneration braking, thereby cushioning the impact on braking force stability while maintaining the fast shutdown response characteristic
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
This configuration maintains a consistent braking force, reducing the variation in deceleration and preventing discomfort for vehicle occupants by compensating for regeneration braking force decreases with increased friction braking, even during power supply interruptions.
Implementation Method 1
a regeneration braking force generated by a motor (electric motor)
Implementation Method 2
hydraulic pressure braking means (friction-type braking apparatus) for pressing friction members against the wheels via a hydraulic pressure to apply hydraulic pressure braking forces
Data Source
AI summary
A vehicle configured to suppress a variation in a deceleration during braking. When a regeneration braking force is generated by a hybrid ECU to brake a hybrid vehicle, and an abnormality occurs to communication between the ECU and a brake ECU, the ECU gradually decreases a magnitude of a target regeneration braking force as the time elapses. On the other hand, the ECU gradually increases a magnitude of a target friction braking force up to a magnitude of a target total braking force as the time elapses. Further, when the vehicle is braked, and power supply to the ECU is shut off to result in an abnormality in the communication between the ECU and the ECU, the ECU finishes the regeneration operation of an electric motor, and the ECU rapidly increases the magnitude of the target friction braking force to the magnitude of the target total braking force.