Variable Pitch Fan Reversing for Harvester Thermal Management
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Solution Overview
Problem
Harvester fan speeds are set at constant speeds regardless of yield, leading to inefficient crop harvesting.
Innovation Solution
A control system for a variable pitch fan that adjusts fan blade pitch based on harvester temperature, ambient temperature, and engine load, using feedback signals to optimize airflow direction and interval, allowing for incremental changes in pitch settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fan speeds are set at constant speeds regardless of yield, then the harvester operates with simple control, but the crop harvesting efficiency deteriorates
Solution Approach 1:
The patent applies dynamics by transitioning from constant fan speed to variable fan speed control. The controller dynamically adjusts fan blade pitch based on real-time feedback from temperature sensors and yield detectors, allowing the system to adapt to changing operating conditions and maximize harvesting efficiency across different crop densities and environmental conditions.
Solution Approach 2:
The patent implements feedback control by using temperature sensors to monitor harvester and ambient temperatures, and yield detectors to measure crop density. This feedback information is fed to the controller which adjusts fan pitch accordingly, creating a closed-loop system that optimizes harvesting efficiency based on actual operating conditions.
2Productivity
If fan blade pitch is adjusted based on temperature and load conditions, then harvesting efficiency improves, but the control system complexity increases
Solution Approach 1:
The patent applies parameter changes by adjusting fan blade pitch angle based on temperature differential (harvester temperature minus ambient temperature) and engine load conditions. The controller modifies operational parameters in real-time to optimize airflow and harvesting efficiency under varying thermal and mechanical loads.
Solution Approach 2:
The system uses feedback from temperature sensors and load sensors to continuously monitor operating conditions and adjust fan pitch accordingly, creating an adaptive control system that responds to actual harvester state rather than relying on pre-set constant parameters.
3Temperature
If fan airflow direction is reversed to cool the harvester, then temperature control improves, but the harvesting operation is interrupted
Solution Approach 1:
The patent applies periodic action by temporarily reversing fan airflow direction at scheduled intervals or when temperature thresholds are reached. The controller briefly changes fan pitch to reverse airflow for cooling, then returns to normal operation, creating a periodic cycle that manages temperature without permanently interrupting harvesting.
Solution Approach 2:
The system dynamically switches between normal forward airflow mode and reverse airflow cooling mode based on temperature conditions and operational timing. This dynamic switching allows the harvester to alternate between harvesting optimization and thermal management modes.
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
Improves crop harvesting efficiency by dynamically adjusting fan speed and airflow direction in response to temperature and load conditions, enhancing yield and reducing operational stress on the harvester.
Implementation Method 1
The variable pitch fan is configured to create an airflow in a first direction
Implementation Method 2
generate a fan reversal signal that temporarily causes the pitch of the plurality of fan blades to change in order to cause the airflow to flow in a second direction, opposite the first direction
Data Source
AI summary
A control system for controlling a pitch of a plurality of fan blades of a variable pitch fan driven by an engine of a harvester. The control system comprises first, second, and third feedback devices that provide first, second, and third feedback signals indicative of at least one harvester temperature, an ambient temperature, and an engine load. A controller is operable to receive the first, second, and third feedback signals, lookup an initial pitch setting, generate an initial pitch setting signal, and compare the harvester temperature to a harvester temperature limit and generate a fan reversal signal if certain conditions are met.