Hydraulic Switch Malfunction Removal via Intermittent Pressure
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Solution Overview
Problem
Existing vehicle hydraulic control circuits face reliability issues due to temporary malfunctions like contact corrosion in hydraulic switches, which can lead to false fail-safe activations, limiting vehicle performance.
Innovation Solution
A control device with a malfunction detecting means and a malfunction removing means that intermittently changes oil pressure or increases electric current to the hydraulic switch, allowing for the removal of oxides or foreign materials, thereby restoring the switch's functionality and preventing false malfunctions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hydraulic switch is used to detect oil pressure supply state, then malfunction detection capability is improved, but false malfunction detection occurs due to contact corrosion
Solution Approach 1:
The control device performs a preliminary malfunction removal operation by intermittently changing oil pressure or increasing electric current before final malfunction detection. This preliminary action cleans oxide or foreign material from the hydraulic switch contact, ensuring that subsequent malfunction detection is not based on false readings caused by contact corrosion.
Solution Approach 2:
The control device applies periodic intermittent oil pressure changes or electric current increases to the hydraulic switch. This periodic action repeatedly opens and closes the switch contact, mechanically removing oxide and foreign material buildup, thereby restoring reliable contact operation and enabling accurate malfunction detection.
2Reliability
If fail-safe is executed based on hydraulic switch malfunction, then safety is improved, but vehicle performance is unnecessarily limited due to temporal malfunction
Solution Approach 1:
Before executing fail-safe based on malfunction detection, the control device first performs preliminary malfunction removal operations. If the malfunction disappears after these removal operations, the control device determines it was a temporal malfunction and avoids unnecessary fail-safe execution, thereby preventing unnecessary vehicle performance limitation while maintaining safety.
Solution Approach 2:
The control device implements a feedback mechanism where malfunction detection triggers preliminary removal operations, and the result of these operations feeds back into the malfunction determination. If the switch恢复正常 after removal operations, the feedback indicates no real malfunction exists, preventing false fail-safe activation and preserving vehicle performance.
3Reliability
If malfunction removing means is added, then reliability of malfunction detection is improved, but device complexity increases
Solution Approach 1:
The control device integrates multiple functions into a single control unit. The same control device that detects malfunctions also performs malfunction removal by intermittently changing oil pressure or increasing electric current. This multi-functionality approach improves malfunction detection reliability without adding separate dedicated removal hardware, thereby minimizing device complexity.
Solution Approach 2:
The hydraulic switch malfunction removal is achieved through self-service mechanisms where the control device uses its existing resources (oil pressure control capability or electric current control capability) to remove malfunctions. The control device serves itself by using its own control functions to clean its own sensors, eliminating the need for external removal devices and reducing overall system complexity.
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 solution improves the reliability of hydraulic switch malfunction detection by removing contact corrosion, ensuring accurate detection and preventing performance limitations, while allowing for malfunction detection without affecting vehicle travel.
Implementation Method 1
the malfunction removing means intermittently changes an oil pressure applied to the hydraulic switch to repeat ON/OFF operations of the contact of the hydraulic switch
Implementation Method 2
the malfunction removing means increases an electric current applied to the hydraulic switch. As a result, an oxide or a foreign material attached to the contact of the hydraulic switch SW can be electrically removed
Data Source
AI summary
A control device for a vehicle hydraulic control circuit having a hydraulic switch disposed on a hydraulic control circuit of an automatic transmission, includes: a malfunction detecting portion configured to detect a malfunction of the hydraulic switch; and a malfunction removing portion configured to execute an operation for restoring a contact of the hydraulic switch when a malfunction of the hydraulic switch is detected.