Construction Machine Pump Torque Control via Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing pump control apparatuses for construction machines inefficiencies lead to decreased work rate due to excessive reduction in input torques of the first and second hydraulic pumps when the discharge pressure of the third hydraulic pump is reduced, resulting in suboptimal utilization of prime mover output.
Innovation Solution
A pump control apparatus that includes a prime mover, variable displacement pumps, a fixed displacement pilot pump, and a controller that adjusts the input torques of the first and second pumps based on the discharge pressure of the third pump, using a regulator and pressure detection mechanisms to optimize torque control and prevent excessive torque decrease.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the discharge pressure of the third hydraulic pump is reduced by a pressure reducing valve to control the input torques of the first and second pumps, then the torques of the first and second pumps are decreased, but the actual input torque of the third pump takes higher values due to spring characteristics of the regulator, resulting in excessive torque decrease and inefficient prime mover output utilization
Solution Approach 1:
The invention introduces a feedback mechanism where the actual discharge pressure of the third hydraulic pump is detected by a pressure sensor and fed back to the controller. The controller then calculates torque correction amounts based on this actual pressure and adjusts the torque control command pressure accordingly, ensuring that the torque decrease of the first and second pumps accurately reflects the actual torque of the third pump, thereby preventing excessive torque reduction and maintaining efficient prime mover output utilization.
Solution Approach 2:
The invention replaces the purely mechanical pressure reducing valve control system with an electronically controlled torque adjustment system. Instead of relying solely on the mechanical spring characteristics of the regulator which cause torque discrepancies, the system uses electronic sensors and controllers to detect actual pressures and calculate appropriate torque corrections, substituting mechanical estimation with precise electronic measurement and control.
2Device complexity
If the input torques of the first and second hydraulic pumps are controlled based on reduced secondary pressure, then torque control is simplified, but the torques are decreased more than the actual input torque of the third pump, leading to suboptimal engine power utilization
Solution Approach 1:
The controller receives feedback from the pressure sensor regarding the actual discharge pressure of the third pump and dynamically adjusts the torque control command pressure for the first and second pumps. This feedback loop ensures that torque control remains accurate despite the mechanical simplifications, maintaining optimal engine power utilization without requiring complex mechanical adjustment mechanisms.
Solution Approach 2:
The invention changes the control parameter from purely mechanical pressure reduction to electronically adjusted torque command pressure. By detecting the actual discharge pressure and calculating torque correction amounts, the system dynamically adjusts the torque parameters of the first and second pumps to match the actual load conditions, optimizing engine power utilization without increasing mechanical complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution ensures efficient use of engine output by increasing the input torques of the first and second hydraulic pumps, maintaining work performance and preventing excessive speed decrease in actuators, even under increased loads, by accurately adjusting torque based on detected discharge pressures.
Implementation Method 1
a pressure sensor that detects the discharge pressure of the third hydraulic pump
Implementation Method 2
first, second, and third variable displacement hydraulic pumps (1, 2, and 3), and a fixed displacement pilot pump (4), all driven by a common prime mover (engine) (5)
Implementation Method 3
regulators (6 and 7) that control the input torques of the hydraulic pumps (1, 2, and 3) respectively on the basis of the discharge pressures of these hydraulic pumps
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The present invention includes a torque correction amount output unit T2 for outputting the torque correction amounts of first and second pumps on the basis of the discharge pressure Pd3 of a third pump detected by pressure detection means 30; and a reference torque output unit T1 for outputting reference torque values of the first and second pumps on the basis of the target revolution speed of a prime mover specified by specifying means. On the basis of the output values Td3 and Te of the above output units, the torque control command pressure is calculated so that the input torques of the first and second pumps are increased. The calculated torque command instruction pressure is then supplied as external command pressure to the varying mechanism of the regulator used for the first and second pumps so as to prevent the input torques of the first and second pumps from being decreased more than necessary. As a result, even when three variable displacement hydraulic pumps are used with the discharge pressure of one of the hydraulic pumps reduced by a pressure reducing valve and further the input torques of the other two hydraulic pumps are decreased by that pressure, the engine output can be efficiently utilized, and the work rate dose not decrease.