Transmission Hydraulic Pressure Calibration for Fault Detection

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Diagnosing faults in electro-hydraulic control systems for transmissions is challenging due to the interdependence of components, leading to time-consuming and costly trial-and-error methods.

Innovation Solution

An electro-hydraulic control system with a control main valve and clutch trim valve, along with an electronic control module, that adjusts main line pressure and detects faults based on status signals from a pressure switch, allowing for the detection of fluid supply issues and leakage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If traditional trial-and-error diagnostic methods are used to identify faulty components in electro-hydraulic control systems, then diagnostic accuracy can be achieved, but diagnostic time and cost increase substantially

Engineering Contradiction:
Improvefault identification accuracyVSAvoiddiagnostic time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent applies preliminary action by pre-calibrating the system to establish baseline relationships between regulator control signals and main line pressure levels. This calibration data is stored and later used to rapidly compare against actual operating conditions, enabling quick fault identification without trial-and-error diagnostics. The calibration process performs preliminary measurements and stores reference values that accelerate subsequent diagnostic operations.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If multiple components are monitored to improve fault detection capability, then diagnostic accuracy improves, but system complexity increases

Engineering Contradiction:
Improvefault detection capabilityVSAvoidsystem complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements feedback by continuously monitoring the relationship between regulator control signals and main line pressure levels, comparing actual measurements against calibrated baseline values. The system provides feedback through diagnostic flags that indicate when deviations exceed predetermined thresholds, suggesting component faults. This feedback mechanism enables reliable fault detection while maintaining relatively simple system architecture by focusing monitoring efforts on critical parameter relationships rather than all possible component states.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP3486531B1Electro-hydraulic control system calibration and diagnostics
Publication Date: 2022.09.28 ALLISON TRANSMISSION INC
  • EP3486531B1 patent drawingFigure 1
  • EP3486531B1 patent drawingFigure 2
  • EP3486531B1 patent drawingFigure 3

AI summary

Various embodiments of methods, apparatus and systems that diagnose and/or detect faults of an electro-hydraulic control system for a transmission are presented. Some embodiments, adjust a main line pressure of the electro-hydraulic control system and detect faults based upon changes in a pressure switch resulting from such adjustments of the main line pressure. The pressure switch may be incorporated into a control main valve or a clutch trim valve of the electro-hydraulic control system.