All-Wheel Drive Hydraulic Pressure Sensor Compensation
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Solution Overview
Problem
Hydraulic fluid pressure sensors in all-wheel drive systems for vehicles experience inaccuracies due to temperature variations, ambient pressure changes, and manufacturing differences, leading to incorrect engagement or disengagement of the all-wheel drive system, which can result in excessive wear and inefficiency.
Innovation Solution
A system that includes an atmospheric pressure sensor and a controller to determine a zero-point offset based on raw pressure sensor readings and known pressure values, especially during idle stop conditions, to create a corrected pressure reading, thereby compensating for errors caused by temperature, altitude, and wear over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic fluid pressure sensor is used to measure pressure in all wheel drive system, then pressure control is enabled for clutch engagement, but measurement precision deteriorates due to temperature variations, atmospheric pressure changes, and manufacturing differences
Solution Approach 1:
The patent applies parameter changes by introducing temperature compensation and atmospheric pressure compensation parameters to correct the raw pressure sensor readings. The controller dynamically adjusts the measured pressure values based on temperature variations and atmospheric pressure changes, transforming the inaccurate raw readings into compensated accurate pressure values that reflect actual hydraulic pressure conditions.
Solution Approach 2:
The patent implements feedback mechanisms by continuously monitoring temperature, atmospheric pressure, and pressure sensor readings, then using this feedback information to calculate compensation values. The compensated pressure values are fed back to the control system to adjust clutch engagement decisions, creating a closed-loop system that maintains measurement accuracy despite environmental variations.
2Device complexity
If pressure sensor readings are not compensated for environmental variations, then device complexity is reduced, but reliability deteriorates due to incorrect engagement or disengagement of all-wheel drive system
Solution Approach 1:
The patent applies universality by making the controller perform multiple functions: it not only controls clutch engagement based on pressure readings but also measures temperature, atmospheric pressure, calculates compensation values, and corrects pressure sensor readings. This multi-functionality eliminates the need for separate compensation devices, maintaining system simplicity while improving reliability.
3Measurement precision
If pressure sensor readings are compensated using temperature and atmospheric pressure data, then measurement precision is improved, but device complexity increases due to additional sensors and processing
Solution Approach 1:
The patent applies merging by combining the compensation functionality into the existing controller unit. The controller integrates temperature sensing, atmospheric pressure sensing, compensation calculation, and pressure correction all within a single control unit, eliminating the need for separate compensation devices and reducing overall system complexity while maintaining measurement precision.
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 provides more accurate control over the all-wheel drive system, reducing errors and extending the lifespan of components by ensuring precise hydraulic pressure management, even under varying conditions.
Implementation Method 1
determine an atmospheric pressure using an atmospheric pressure sensor coupled to the vehicle
Implementation Method 2
The hydraulic fluid pressure may be measured using a hydraulic fluid pressure sensor, which may measure the pressure of the hydraulic fluid using an internal diaphragm, and may output the measured pressure as a voltage signal
Data Source
AI summary
A method may be provided for correcting a raw signal supplied by a pressure sensor in an all wheel drive system having a hydraulic pump and a hydraulic fluid. The method may include measuring the raw signal supplied by the pressure sensor, determining when the all wheel drive system is in a state where the hydraulic fluid is at a known pressure determined independently from the pressure sensor, determining a new zero-point offset by comparing the raw signal to a voltage value associated with the known pressure, and creating a corrected voltage signal by adjusting the raw signal based on the new zero-point offset. This corrected voltage signal may be converted into a pressure reading for controlling the all wheel drive system.