Hydraulic Pump Control via Temperature-Adaptive Pressure Response
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Solution Overview
Problem
Existing hydraulic systems face issues with pressure buildup, leading to reduced responsiveness and potential component damage due to excessive pressure and temperature, as they struggle to maintain desired pressure levels while operating efficiently.
Innovation Solution
A hydraulic system with a controller that adjusts the output of the hydraulic pump based on pressure and temperature signals, varying the rate of response to reduce pressure, thereby preventing excessive pressure and temperature in the fluid circuit, using cross-over relief valves and sensors to manage fluid flow and torque distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If pressure relief valves are used to limit maximum pressure in the hydraulic circuit, then pressure control is improved, but machine responsiveness to operator commands is reduced
Solution Approach 1:
The patent implements dynamic pressure control by varying the response rate of pressure reduction based on fluid temperature. The controller adjusts the rate at which pump output is reduced when pressure reaches the pressure limit, making the pressure control system adaptive rather than static. This dynamic approach allows the system to maintain pressure control while minimizing impact on machine responsiveness under different operating conditions.
Solution Approach 2:
The patent changes the parameter of response rate based on temperature conditions. When fluid temperature is below a threshold, the controller reduces pump output at a first rate; when temperature exceeds the threshold, it reduces at a second rate. This parameter change allows the system to balance pressure control with machine responsiveness according to thermal conditions of the hydraulic fluid.
2Stress or pressure
If pump output is reduced to maintain pressure within limits, then pressure control is improved, but system productivity is reduced
Solution Approach 1:
The system dynamically adjusts pump output reduction based on real-time temperature measurements. Rather than continuously limiting pressure regardless of conditions, the controller monitors fluid temperature and only applies pressure control measures when temperature exceeds the threshold. This dynamic operation maintains pressure control while maximizing productivity during acceptable temperature ranges.
Solution Approach 2:
The controller changes the operational parameter of pump output based on temperature conditions. When fluid temperature is within acceptable limits, the system operates at full productivity. When temperature exceeds the threshold, the controller modifies pump output to maintain pressure control. This conditional parameter change resolves the contradiction between pressure maintenance and productivity.
3Power
If pressure is allowed to build to higher levels, then machine power output is improved, but component damage risk increases
Solution Approach 1:
The system takes preliminary action by continuously monitoring fluid temperature and proactively controlling pump output before excessive pressure can develop. When temperature approaches the threshold, the controller preemptively adjusts pump operation to prevent pressure buildup that could lead to component damage. This preliminary control action protects components while allowing the system to operate at high power levels during safe temperature ranges.
Solution Approach 2:
The patent implements a feedback control mechanism where the controller continuously receives temperature signals from the temperature sensor and adjusts pump output accordingly. This closed-loop feedback system ensures that pressure remains within safe limits by responding to temperature changes, thereby protecting components while allowing maximum power output during acceptable operating conditions.
Data Source
AI summary
A hydraulic system includes a hydraulic transmission including a hydraulic pump configured to be coupled to a prime mover, a hydraulic motor configured to be coupled to an output shaft, and fluid lines coupling the hydraulic pump to the hydraulic motor to provide a fluid circuit providing flow communication between the hydraulic pump and the hydraulic motor, such that operation of the hydraulic pump provides fluid flow to the hydraulic motor, and the hydraulic motor supplies torque to the output shaft. A controller is configured to control operation of the hydraulic transmission. The controller is configured to receive signals indicative of pressure in the fluid circuit and reduce an output of the hydraulic pump when the pressure in the fluid circuit reaches a pressure level, and a rate of response of the reduction of the output of the hydraulic pump is varied based on a temperature of fluid in the fluid circuit.