Work Machine Hydraulic Speed Control via Temperature Feedback
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Solution Overview
Problem
Existing hydraulic systems for work machines face challenges in efficiently managing engine revolution speed based on fluid temperature, leading to inadequate operability due to high pressures at low temperatures and limited performance at varying temperature conditions.
Innovation Solution
A hydraulic system for work machines that includes a prime mover, hydraulic pumps, temperature sensors, and a controller to determine and adjust the upper limit revolution speed of the prime mover based on initial and subsequent fluid temperatures, thereby optimizing engine performance and reducing pressure on hydraulic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the engine revolution speed is restricted when fluid temperature is low, then the pressure on hydraulic devices is reduced, but the operability and performance of the work machine deteriorates
Solution Approach 1:
The upper limit revolution speed is not fixed but dynamically adjusted based on fluid temperature measurements. The controller updates the speed limit in real-time as temperature changes, allowing the system to transition from a static restriction to a dynamic adaptation that responds to actual operating conditions.
Solution Approach 2:
The system changes the parameter of upper limit revolution speed according to the parameter of fluid temperature. When temperature increases, the speed limit parameter is adjusted upward, allowing the engine to operate at higher speeds safely. This parameter coupling resolves the contradiction by making the restriction adaptive rather than absolute.
2Device complexity
If the upper limit revolution speed is determined only by initial temperature, then the pressure control is simple, but the performance is limited when temperature changes during operation
Solution Approach 1:
The system implements feedback by continuously measuring fluid temperature and using this information to adjust the upper limit revolution speed. The temperature sensor provides ongoing data to the controller, which modifies the speed limit accordingly, creating a closed-loop control system that adapts to temperature changes during operation.
Solution Approach 2:
The controller determines the upper limit revolution speed in advance based on the measured fluid temperature before the engine operates at that speed. This preliminary determination ensures that the engine never exceeds safe operating parameters while still allowing optimal performance when conditions permit.
Data Source
AI summary
A work machine includes a prime mover, a hydraulic pump to be operated by the prime mover to output an operation fluid, a hydraulic device to be operated by the operation fluid, a measurement sensor to measure a first temperature and a second temperature, the first temperature being a temperature of the operation fluid at starting of the prime mover, the second temperature being a temperature of the operation fluid after the starting of the prime mover, and a controller including a determiner to determine an upper limit revolution speed based on the first temperature, the upper limit revolution speed being an upper limit of a revolution speed of the prime mover, and a changer to change the upper limit revolution speed based on the second temperature.