Variator Fault Detection Circuit for CVT Reliability
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Solution Overview
Problem
Current variator fault detection systems in continuously variable transmissions lack effective methods to accurately detect faults in shift valves and variator control circuits, leading to potential transmission performance issues and failures.
Innovation Solution
A variator fault detection circuit and method using shift valves, pressure switches, and electro-hydraulic actuators within a hydraulic control circuit, where the electronic control unit monitors the status of these components to determine faults and initiate recovery actions, ensuring the system's operational integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fault detection methods are added to monitor shift valves and variator control circuits, then reliability is improved, but device complexity increases
Solution Approach 1:
The system uses its own operational parameters (electro-hydraulic actuator status and pressure switch readings) to self-diagnose faults in shift valves and variator control circuits, eliminating the need for external detection devices and maintaining system simplicity while improving reliability
Solution Approach 2:
The electronic control unit continuously monitors feedback from pressure switches and electro-hydraulic actuators to detect faults in shift valves and variator control circuits, enabling real-time fault detection using existing system components without adding external sensing devices
2Measurement precision
If multiple pressure switches and actuators are used for fault detection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The system repurposes existing pressure switches and electro-hydraulic actuators as detection sensors, allowing them to serve both their original control functions and fault detection functions simultaneously, thereby improving measurement precision without adding dedicated detection components
Solution Approach 2:
The pressure switches and electro-hydraulic actuators perform multiple functions: they control variator operation during normal operation and simultaneously serve as sensors for fault detection by monitoring their own operational status, eliminating the need for separate detection components
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 solution enables timely detection and response to faults, preventing transmission failures and ensuring continuous operation by accurately monitoring the status of shift valves and variator control components, thereby enhancing the reliability of continuously variable transmissions.
Implementation Method 1
a first pressure switch coupled to the second port of the first shift valve, a second pressure switch coupled to the second port of the second shift valve
Implementation Method 2
a first electro-hydraulic actuator coupled to the first shift valve, and a second electro-hydraulic actuator coupled to the second shift valve
Implementation Method 3
The variator torque is controlled by a hydraulic circuit, which includes hydraulic actuators (i.e., pistons) that apply an adjustable force to the rollers
Data Source
AI summary
A variator fault detection system for a continuously variable transmission is incorporated into a hydraulic control circuit that controls fluid pressure applied to a variator of the continuously variable transmission. The hydraulic control circuit for the variator includes a number of electrically-controlled shift valves and pressure control valves. Sensing devices are multiplexed to these valves to detect a number of different possible fault states relating to the variator shift valves and the variator pressure control valves.