Hydrostatic Mower Transmission Speed Control
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Solution Overview
Problem
Mowing machines consume excessive fuel, produce noise and vibration, and experience wear and tear due to operating at maximum engine speed to maintain optimal mower blade speed, which is not efficiently controlled.
Innovation Solution
A mower blade speed control system with a hydrostatic transmission, electronic control unit, and mode selection switch that allows the engine to run at a lower economy speed while maintaining constant preset blade speed, reducing fuel consumption, noise, and wear by adjusting engine speed based on load and using hydrostatic transmissions to control blade and traction drive speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the engine runs at maximum speed to maintain optimal mower blade speed, then cut quality is improved, but fuel consumption increases
Solution Approach 1:
The patent applies dynamics by making the engine speed variable rather than fixed at maximum. The electronic control unit dynamically adjusts engine speed based on actual mowing conditions, allowing the system to maintain optimal blade speed only when necessary while operating at lower speeds during light-load conditions, thus reducing fuel consumption while preserving cut quality when needed.
Solution Approach 2:
The system changes the operating parameters of the engine by using a hydrostatic transmission with variable displacement pumps and motors. This allows continuous adjustment of the relationship between engine speed and blade speed, enabling the engine to operate at lower RPM while maintaining optimal blade tip speed through transmission ratio changes, thereby reducing fuel consumption without sacrificing cut quality.
2Manufacturing precision
If the engine runs at maximum speed to maintain optimal mower blade speed, then cut quality is improved, but noise increases
Solution Approach 1:
The system dynamically adjusts engine speed based on actual mowing conditions rather than running continuously at maximum speed. The electronic control unit monitors load conditions and reduces engine speed when full power is not needed, thereby maintaining optimal blade speed for cut quality while significantly reducing noise generation during lighter operating conditions.
3Manufacturing precision
If the engine runs at maximum speed to maintain optimal mower blade speed, then cut quality is improved, but machine wear and tear increases
Solution Approach 1:
The patent implements dynamic engine speed control that adjusts operating conditions based on actual demand. By reducing engine speed during periods when maximum power is not required, the system maintains optimal blade speed for cut quality only when necessary, thereby reducing mechanical stress and wear on engine and transmission components while preserving cutting performance.
4Speed
If the engine runs at maximum speed to maintain optimal mower blade speed, then blade speed is maintained, but fuel consumption increases
Solution Approach 1:
The patent introduces a hydrostatic transmission system with variable displacement pumps and motors as an intermediary between the engine and the mower blades. This intermediary allows decoupling of engine speed from blade speed, enabling the engine to operate at lower speeds while maintaining optimal blade tip speed through hydraulic transmission ratio adjustments, thus reducing fuel consumption without compromising blade speed.
Solution Approach 2:
The system changes the transmission parameters by using variable displacement hydraulic pumps and motors controlled by the electronic control unit. This allows continuous adjustment of the speed ratio between engine and blades, enabling the engine to operate at lower RPM while maintaining optimal blade speed through transmission parameter changes, thereby reducing fuel consumption.
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 system achieves optimal mower blade speed while reducing fuel consumption, noise, and machine wear by dynamically adjusting engine speed and transmission displacement, allowing for efficient operation at lower engine speeds without compromising cut quality.
Implementation Method 1
a hydrostatic mow transmission, driving a plurality of traction drive wheels with a hydrostatic traction drive transmission
Implementation Method 2
An electronic control unit monitors load of the engine
Data Source
AI summary
A mower blade speed control system with an electronic control unit providing engine speed commands to an internal combustion engine having a maximum power speed and a reduced economy speed, and a continuously variable transmission with variable displacement providing rotational power from the engine to a plurality of mower blades. The electronic control unit monitors engine load and automatically adjusts engine speed and the displacement of the continuously variable transmission in response to engine load to achieve a constant rotational speed of a plurality of mower blades at different engine speeds.