Parking Brake PLC Towing Mode Control
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Solution Overview
Problem
Existing parking brake systems for vehicles without hydraulic systems, like the Toyota Land Cruiser, face challenges in releasing the brake when the engine is disabled, leading to inconvenient and hazardous solutions such as using jumper wires or hydraulic hand pumps, which can result in safety hazards and potential brake system malfunctions.
Innovation Solution
A programmable logic controller (PLC) is integrated into the brake system to temporarily ignore engine oil pressure switch communications, allowing the brake to be released without special tools or leaving the driver's seat, enabling a 'towing mode' that preserves brake engagement functionality even when the engine is off.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine is shut off to save fuel or due to breakdown, then fuel consumption is reduced, but the parking brake cannot be released making the vehicle immobile
Solution Approach 1:
The system pre-conditions the brake release by monitoring engine run time and automatically enabling brake release functionality after a predetermined period, eliminating the need for manual intervention and allowing brake release without engine operation
Solution Approach 2:
The patent replaces the traditional mechanical linkage between engine operation and brake release with an electronic control system using switches and circuitry that can independently control brake release based on time-based logic rather than direct mechanical connection
2Ease of operation
If jumper wires are used to bypass relays to release the brake, then the brake can be released for towing, but the operator must leave the vehicle and work with exposed electrical components creating safety hazards
Solution Approach 1:
The system provides self-service brake release functionality through the driver's seat interface, allowing the operator to release brakes without leaving the protected cabin environment or handling exposed electrical components
Solution Approach 2:
The patent introduces an intermediary control system with switches and relays that mediates between the driver's input and the brake release mechanism, eliminating the need for direct manipulation of electrical components and providing a safe interface
3Volume of moving object
If the pump kit is mounted behind the seat, under the hood, or in the bed of the truck, then space is utilized, but the operator must physically access these locations to perform brake release operations
Solution Approach 1:
The system segments the control functions by separating the control interface (switches on dash panel) from the execution mechanism (pump kit in remote location), allowing the operator to interact with controls in the accessible cabin area while the pump operates remotely
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
The PLC-based system safely and conveniently releases the parking brake during towing without requiring special tools or training, ensuring the driver remains in control and preventing potential hazards associated with bypassing mechanical relays or using hand pumps, while maintaining normal brake operation when the vehicle is repaired.
Implementation Method 1
The solenoid is a normally open device. This means that in absence of electrical power, the solenoid will open the brake line to tank
Implementation Method 2
The electric motor turns a hydraulic pump, which is used to create pressure to release the brakes
Data Source
AI summary
A parking brake system includes an engine oil pressure switch normally controlling the activation of a parking brake. The controller is actuated to temporally ignore a communication from the engine oil pressure switch so that the brake may be released even when the engine is disabled.