Remotely Actuated Tow Bar Latch for High-Speed Vehicle Testing
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Solution Overview
Problem
Hybrid and electric vehicles present challenges in disengaging their drivetrains during high-speed tests, as they cannot be easily accelerated to test speeds without damaging the vehicle or interfering with airflow, and existing towing methods are either ineffective or unsafe.
Innovation Solution
A remotely controlled tow bar assembly with a latch mechanism that can be actuated from a distance, allowing for the release of the towed vehicle from the towing vehicle, using a solenoid, magnetic plunger, or linear motor to shift between latched and unlatched positions, enabling safe and controlled disengagement during tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hybrid and electric vehicles are pushed from the rear to reach test speeds, then the vehicles can be accelerated to desired speeds, but the test vehicle may be damaged and it is difficult to control
Solution Approach 1:
The patent replaces the mechanical pushing method with an aerodynamic towing method. A towing cable connects the test vehicle to a towing vehicle, allowing the test vehicle to be pulled to test speeds without direct mechanical contact that could cause damage. The towing cable transmits force through tension rather than direct pushing contact.
2Speed
If the towing vehicle is used to accelerate the test vehicle to desired speeds, then the test vehicle can reach test speeds, but the towing vehicle may interfere with the test results by disturbing the air flow around the test vehicle
Solution Approach 1:
The patent extracts the towing vehicle from the immediate vicinity of the test vehicle during the actual test. The towing vehicle accelerates the test vehicle to the desired speed, then moves ahead and releases the towing cable, allowing the test vehicle to coast without interference. This separates the acceleration function from the testing function.
Solution Approach 2:
The towing vehicle performs the acceleration action before the actual test begins. The test vehicle is brought up to speed while being towed, then the towing cable is released, and the vehicle coasts for the aerodynamic drag test. This preliminary acceleration phase is completed before the measurement phase.
3Speed
If the towing cable is not released from the towed vehicle, then the towed vehicle can be accelerated to test speeds, but the towing cable may interfere with the test results
Solution Approach 1:
The patent makes the towing cable connection dynamic rather than static. The towing cable is connected during acceleration but is designed to be released during the test phase. This dynamic connection allows the system to adapt to different operational phases: connected for acceleration, disconnected for testing.
Solution Approach 2:
The towing cable is released at a predetermined point before the actual aerodynamic drag test begins. This preliminary release action ensures that the cable does not interfere with the test measurements while having already served its purpose of accelerating the vehicle to the required speed.
4Ease of operation
If a cable release mechanism like glider aircraft is used, then the release operation is simple and effective, but it requires a cable guide system and can only be operated by the pilot of the towed or towing aircraft
Solution Approach 1:
The patent replaces the mechanical cable guide system with a magnetic release mechanism. Magnets are positioned on the towing cable and correspondingly on the test vehicle, allowing the cable to be held in place during acceleration and then automatically released when the magnetic force is overcome or deactivated, eliminating the need for complex mechanical guides.
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 safe and controlled disengagement of hybrid and electric vehicles during high-speed tests, preventing damage and minimizing interference with airflow, allowing for accurate measurement of aerodynamic and mechanical drag.
Implementation Method 1
using a solenoid, magnetic plunger, or linear motor to shift between latched and unlatched positions
Implementation Method 2
using a solenoid, magnetic plunger, or linear motor to shift between latched and unlatched positions
Implementation Method 3
using a solenoid, magnetic plunger, or linear motor to shift between latched and unlatched positions
Data Source
AI summary
A vehicle tow bar assembly having a latch assembly and a remotely operated actuator for unlatching the tow bar assembly from a tow line. The latch assembly may have a pivot lever that is retained by a latch pin until released. Alternatively, the latch assembly may have a pair of jaws that are opened by a linear motor and a set of cams. A method of towing a vehicle with a tow bar assembly that is unlatched and released when the vehicle is moving at a selected speed in a test procedure.