Work Vehicle Engine Speed Hold for Uniform Operation
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Solution Overview
Problem
Existing work vehicle technologies, such as those described in JP 2009-287469A, often result in variations in work operations due to non-uniform engine rotation speeds, requiring drivers to focus on setting rotation speeds, which increases labor and reduces efficiency.
Innovation Solution
A work vehicle equipped with a first operating tool to change engine rotation speed and transmission deceleration rate, a rotation speed controller to maintain constant engine speed upon instruction, and a second operating tool to hold engine speed constant, allowing vehicle speed to be increased independently of engine rotation speed, with optional notification and mode switching features.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the engine rotation speed is increased to increase vehicle speed, then the vehicle speed increases, but the rotation speed of the work unit increases causing non-uniform work results
Solution Approach 1:
The patent separates the control of vehicle speed from the control of engine rotation speed. The transmission deceleration rate is controlled independently to adjust vehicle speed while the engine rotation speed is held constant, thus segmenting the coupled control into independent controls that resolve the contradiction between speed increase and work uniformity
Solution Approach 2:
The transmission deceleration rate serves as an intermediary variable that mediates between engine rotation speed and vehicle speed. By adjusting the transmission deceleration rate, the system can change vehicle speed without changing engine rotation speed, thus preventing work unit speed variations while achieving speed increase
2Ease of operation
If the driver manually adjusts the accelerator pedal to maintain constant engine speed, then engine speed can be controlled, but the driver's workload increases and efficiency decreases
Solution Approach 1:
The rotation speed controller automatically maintains constant engine rotation speed without requiring continuous manual adjustment by the driver. The controller self-regulates the accelerator pedal position based on feedback, making the system self-serving and eliminating the need for constant driver intervention, thus reducing workload while maintaining productivity
Solution Approach 2:
The system implements feedback control where the rotation speed controller continuously monitors engine rotation speed and automatically adjusts the accelerator pedal position to maintain the set speed. This closed-loop feedback mechanism eliminates manual adjustment needs and optimizes driver efficiency
3Speed
If the accelerator pedal is operated to change engine speed, then engine rotation speed changes, but the transmission deceleration rate also changes causing vehicle speed to fluctuate
Solution Approach 1:
The patent segments the control functions by separating engine rotation speed control from transmission deceleration rate control. The rotation speed controller independently manages engine speed while another control mechanism manages transmission deceleration rate, preventing coupled fluctuations and achieving independent stabilization of both parameters
Data Source
AI summary
A work vehicle includes an engine, a transmission to change a received rotational force to a rotational force at a gear ratio that corresponds to a desired vehicle speed and output the changed rotational force, a first operating tool to change the rotation speed of the engine and a deceleration rate of the transmission, a rotation speed controller to control the rotation speed of the engine based on an input provided to the first operating tool, and a second operating tool to receive a holding instruction to hold the rotation speed of the engine constant. In response to the holding instruction being inputted to the second operating tool, the rotation speed controller is configured or programmed to disable control of the rotation speed of the engine which control is based on the input provided to the first operating tool, and hold the rotation speed of the engine constant in accordance with the holding instruction.