Wheel Loader Engine Torque Control for Fuel Efficiency
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Solution Overview
Problem
The ease of operation of wheel loaders is reduced due to rapid variations in engine torque when switching from high-output to low-output modes, leading to increased fuel consumption.
Innovation Solution
A wheel loader control method that adjusts the engine's upper torque limit based on vehicle speed, acceleration, and engine rotation speed, allowing for variable reduction in torque during low-load conditions to minimize operational disruption and optimize fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine torque curve is completely changed when switching from high-output mode to low-output mode, then fuel consumption is reduced, but the ease of operation deteriorates due to rapid torque variation
Solution Approach 1:
The patent applies dynamics by making the torque reduction amount variable rather than fixed. The controller adjusts the torque reduction dynamically based on detected vehicle speed, vehicle acceleration, and engine rotation speed. This allows the system to adapt the torque curve transition smoothly according to real-time operating conditions, resolving the contradiction between fuel efficiency and operational smoothness.
Solution Approach 2:
The patent changes the parameter of torque reduction amount from a fixed value to a variable value that depends on operating conditions. By modifying how the torque parameter is adjusted during mode switching, the system achieves both fuel savings and operational comfort. The torque reduction amount is calculated based on multiple parameters including vehicle speed, acceleration, and engine rotation speed.
2Ease of operation
If the torque difference between low-output mode and high-output mode is reduced, then rapid torque variation is inhibited, but the fuel consumption reduction effect is lessened
Solution Approach 1:
The system dynamically adjusts the torque reduction amount based on real-time operating conditions rather than using a fixed reduction. This allows the torque difference to be optimized for each specific situation, maintaining ease of operation when needed while maximizing fuel savings when appropriate.
Solution Approach 2:
The patent changes the torque reduction from a static parameter to a dynamic parameter that varies with operating conditions. By changing how the torque parameter is determined (based on vehicle speed, acceleration, and engine rotation speed), the system resolves the contradiction between operational smoothness and fuel efficiency.
3Use of energy by moving object
If a fixed torque reduction amount is applied in low-output mode, then fuel consumption is reduced, but operational smoothness deteriorates during rapid acceleration
Solution Approach 1:
The system applies dynamics by continuously adjusting the torque reduction amount based on detected acceleration and speed changes. During rapid acceleration, the system reduces or eliminates torque reduction to maintain operational smoothness, while during steady-state operation, it applies full torque reduction for fuel savings.
Solution Approach 2:
The patent changes the torque reduction parameter from fixed to variable by incorporating acceleration and speed data. This allows the system to adapt the torque characteristics to match actual operational needs, resolving the contradiction between fuel efficiency and operational stability.
Data Source
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AI summary
An objective of the present invention is to provide a work vehicle and a work vehicle control method that can inhibit a reduction in the ease of operation and improve the effect of reduced fuel consumption. The work vehicle comprises a controller (10). The controller (10) determines whether low-load conditions indicating that the vehicle is in a low-load state are satisfied. The controller (10) controls the engine (21) when the low-load conditions are satisfied so that the upper limit value of the output torque of the engine (21) is made less than when the low-load conditions are not satisfied. Also, the controller (10) varies the reduction amount of the upper limit value of the output torque of the engine (21) when the low-load conditions are satisfied, in accordance with variation in at least one among the detected vehicle speed, the vehicle acceleration, and the engine-rotation-speed acceleration, and in accordance with variation in the detected engine rotation speed.