Sensor-Controlled Hydraulic Pump for Mixed Consumer Demand
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Solution Overview
Problem
Hydraulic systems in work machines, such as excavators, face inefficiencies due to the challenge of combining pressure-controlled and volume-controlled auxiliary consumers with existing technologies being susceptible to vibration and design complexity, leading to energetic inefficiencies and torque issues during startup.
Innovation Solution
A hydraulic system with an adjustable pump electrically controlled by a sensor-based control arrangement that detects the needs of both pressure-controlled and quantity-controlled consumers, allowing for simultaneous supply without complex vibration-prone control arrangements, achieving energy savings and reduced torque during startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If pressure-controlled and volume-controlled auxiliary consumers are supplied by separate hydraulic pumps, then each consumer receives appropriate control, but the system complexity increases and energy efficiency decreases
Solution Approach 1:
The patent combines multiple hydraulic pumps (pressure-controlled and volume-controlled) into a single integrated pump unit. This pump features a common control mechanism that can simultaneously or selectively supply different consumers with appropriate pressure or volume control, thereby reducing the number of separate pumps while maintaining proper control for each consumer type.
Solution Approach 2:
The integrated pump is designed with multi-functional capability to serve both pressure-controlled consumers (such as fan drives) and volume-controlled consumers (such as hydraulic steering and brakes). The pump can operate in different modes depending on which consumers are active, providing universal supply functionality.
2Stress or pressure
If pressure-controlled auxiliary consumers are supplied by pressure-controlled hydraulic pumps, then pressure requirements are met, but energy efficiency decreases when consumers temporarily require no hydraulic energy
Solution Approach 1:
The pump control system is designed to be dynamic rather than static. It can adjust its operation mode based on real-time demand from consumers, switching between pressure-controlled mode and volume-controlled mode as needed. This dynamic adaptation allows the pump to avoid continuous operation at constant pressure when full pressure is not required, thereby reducing energy waste.
Solution Approach 2:
The pump's operational parameters (pressure and volume) are made variable based on consumer demand. Instead of maintaining constant pressure regardless of need, the system changes its pressure and volume output parameters dynamically to match the actual requirements of active consumers, improving energy efficiency.
3Device complexity
If combined variable displacement and pressure control is used for a common variable displacement pump, then a single pump supplies both consumer types, but the control system exhibits susceptibility to oscillations
Solution Approach 1:
The patent introduces a priority valve as an intermediary hydraulic component that mediates between the pump output and different consumers. This priority valve hydraulically prioritizes certain consumers (such as steering) over others, providing inherent stability through hydraulic pressure-based control rather than purely electronic or mechanical feedback loops that may oscillate.
Solution Approach 2:
The patent replaces complex electronic or feedback-based control mechanisms with simpler hydraulic-mechanical control elements such as priority valves and pressure-regulated mechanisms. These hydraulic-mechanical elements provide inherent stability through their physical design and pressure-based operation, avoiding the oscillation issues that can arise from electronic control systems.
Data Source
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AI summary
The invention relates to a hydraulic system comprising at least two hydraulic consumers, at least one of which is pressure-controlled and at least one of which is flow-controlled, an adjustable hydraulic pump that supplies the at least two consumers together, and a control arrangement. According to the invention, the hydraulic pump is electrically controlled by means of the control arrangement, wherein the control arrangement comprises a control unit and sensors connected to the control unit for detecting at least one parameter characterizing the demand of a consumer, wherein the control unit is configured to determine, using the at least one detected parameter, the pressure required by a pressure-controlled consumer and the flow rate required by a flow-controlled consumer, and to control the hydraulic pump such that the required pressure and flow rate are provided.The invention further relates to a work machine, in particular a hydraulic excavator, with such a hydraulic system.