Work Machine Transmission Control for Low-Output Acceleration Recovery
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Solution Overview
Problem
In work machines, the low-output mode selected on flat ground or low-gradient roads leads to decreased vehicle speed and acceleration, and increasing engine output does not immediately address these issues, making it difficult to quickly suppress reductions in speed and acceleration.
Innovation Solution
A work machine with a controller that selectively executes a first and second mode, where the second mode limits the target tractive force, and adjusts the transmission gear ratio based on detected acceleration, allowing for quick suppression of speed and acceleration reductions by alleviating the target tractive force limit when acceleration falls below a threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the low-output mode is selected to improve fuel consumption, then fuel efficiency is improved, but the vehicle speed and acceleration are decreased
Solution Approach 1:
The patent implements dynamic switching between low-output mode and high-output mode based on real-time acceleration detection. When acceleration falls below a threshold, the system transitions from low-output mode to high-output mode, making the system adaptable rather than static. This resolves the contradiction by allowing the system to optimize fuel consumption during normal operation while quickly responding to speed requirements when needed.
Solution Approach 2:
The patent uses acceleration sensors to continuously monitor the actual acceleration of the work machine and feeds this information back to the control unit. Based on this feedback, the control unit determines whether to maintain low-output mode or switch to high-output mode. This closed-loop feedback mechanism ensures that fuel efficiency is maintained while automatically responding to speed requirements.
2Speed
If the engine output is increased to suppress reduction in vehicle speed, then vehicle speed is maintained, but the actual output does not increase immediately
Solution Approach 1:
The patent uses acceleration detection as a preliminary indicator of speed requirements. When acceleration falls below the threshold, the system proactively switches to high-output mode before significant speed reduction occurs. This preliminary action based on acceleration feedback allows the system to anticipate and prevent speed loss rather than reacting after the fact.
Solution Approach 2:
The system dynamically switches between operational modes based on real-time acceleration conditions. Rather than relying on slow engine output adjustments, the patent implements mode switching that immediately changes the tractive force characteristics, providing a dynamic response to speed requirements that overcomes the lag in engine output response.
3Use of energy by moving object
If the target tractive force is limited in low-output mode, then fuel consumption is improved, but the acceleration capability is reduced
Solution Approach 1:
The patent implements feedback control where acceleration sensors monitor the actual acceleration and feed this information to the control unit. When acceleration falls below the threshold, the system increases the target tractive force by switching to high-output mode. This feedback mechanism ensures that tractive force is optimized for fuel consumption during normal operation while automatically increasing when acceleration capability is required.
Solution Approach 2:
The patent makes the tractive force limitation dynamic rather than fixed. The system switches between limited tractive force (low-output mode) and unlimited tractive force (high-output mode) based on real-time acceleration conditions. This dynamic adjustment resolves the contradiction by allowing fuel-efficient operation during normal conditions while maintaining full acceleration capability when needed.
Data Source
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AI summary
A controller selectively executes a first mode and a second mode. In the second mode, a target tractive force of a machine is limited in comparison to the first mode. The controller weakens limitation of the target tractive force and determines the target tractive force when an acceleration of the machine during the second mode is less than a predetermined acceleration threshold. The controller determines a target transmission gear ratio in accordance with the target tractive force. The controller controls a transmission based on the target transmission gear ratio.