Wheel Loader Engine Torque Control for Dump Approach
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Solution Overview
Problem
Wheel loaders experience discomfort and reduced fuel economy due to abrupt changes in engine output torque during operations like dump approaches, where torque requirements vary with vehicle speed and tractive force, leading to inefficient engine control.
Innovation Solution
A wheel loader system with a travel mechanism, working machine, and engine output torque control parts that detect vehicle speed, tractive force, and work conditions to adjust engine output torque based on torque upper value information, reducing torque output when conditions allow, thereby improving fuel economy and operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If engine output torque line is switched from low output to high output during dump approach, then engine output torque is sufficient for the operation, but engine output characteristics change substantially causing operator discomfort
Solution Approach 1:
The patent applies dynamics by making the engine output torque characteristics adjustable rather than fixed. The ECU dynamically changes the torque upper value information based on detected vehicle speed and tractive force, allowing the engine output characteristics to adapt continuously to changing operational conditions. This resolves the contradiction by enabling sufficient torque during dump approach while avoiding abrupt changes that cause operator discomfort.
Solution Approach 2:
The patent changes the parameter of engine output torque upper value based on vehicle speed and tractive force conditions. By storing multiple torque upper value information sets and selecting appropriate ones based on detected parameters, the system provides sufficient torque when needed while maintaining smooth characteristics during transitions, thereby resolving the contradiction between power sufficiency and operator comfort.
2Loss of energy
If engine is controlled based on low output engine output torque line when not excavating or traveling up slope, then fuel consumption is reduced, but engine output torque may be insufficient during dump approach
Solution Approach 1:
The system dynamically adjusts engine output torque characteristics based on real-time detection of vehicle speed and tractive force. During normal operation, it maintains low output characteristics for fuel economy, but automatically switches to appropriate high output characteristics when dump approach conditions are detected, resolving the contradiction between fuel consumption and power sufficiency.
Solution Approach 2:
The patent implements feedback control by detecting vehicle speed and tractive force, then using this information to adjust engine output torque characteristics. The ECU continuously monitors operational conditions and modifies torque output accordingly, ensuring fuel economy during normal operation while providing sufficient power during dump approach through feedback-based adjustment.
3Device complexity
If switch to high output torque line is uniform based on predetermined conditions, then control is simplified, but fuel economy is reduced due to unnecessary high torque output
Solution Approach 1:
The patent changes the control approach from uniform switching based on simple predetermined conditions to parameter-based switching that considers vehicle speed and tractive force. By storing torque upper value information corresponding to different speed and force conditions, the system achieves precise torque control that improves fuel economy while maintaining manageable complexity through structured parameter management.
Data Source
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AI summary
Predetermined torque characteristics are obtained by multiplying by a predetermined ratio that is less than 100%, the upper value of engine output torque from the engine output torque line, for at least part of the range of engine rotation speed. Torque upper value information defines the upper value of engine output torque that changes in conformance with vehicle speed and tractive force. When predetermined conditions for determination are satisfied, an engine output torque control part controls engine output torque based on torque upper value information. The predetermined conditions for determination at the least include that a travel condition is forward travel, that a work condition is laden condition and that a raise operation is being performed by the working machine. When the predetermined conditions for determination are not satisfied the engine output torque control part controls engine output torque based on predetermined torque characteristics.