Electrically Powered Hydraulic System Noise Control via Dual-Range Motor Speed
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Solution Overview
Problem
Working machines like wheel loaders generate high noise levels due to their hydraulic systems, creating an unsuitable working environment for operators and crew.
Innovation Solution
An electrically powered hydraulic system with an electric motor that maintains constant speed in one operating range and varies speed in another, combined with an electronically controlled control valve to manage hydraulic fluid flow, reducing noise and maintaining functionality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the electric motor varies its rotational speed to control hydraulic fluid flow, then the hydraulic system can provide different operation speeds, but the noise level increases and becomes more variable
Solution Approach 1:
The operating range of the operator input device is divided into at least two distinct operating ranges. In the first operating range, the electric motor maintains constant rotational speed while the control valve adjusts hydraulic flow. In the second operating range, the electric motor varies its rotational speed to control hydraulic flow. This segmentation allows the system to provide different operation speeds while minimizing noise in the first range.
Solution Approach 2:
The system changes the control parameter from electric motor rotational speed to control valve displacement for the first operating range, thereby reducing noise. For the second operating range, the system switches to varying electric motor rotational speed to provide higher operation speeds when needed. This parameter change allows the system to optimize between noise reduction and performance.
2Object-generated harmful factors
If the electric motor maintains constant rotational speed, then noise variations are reduced, but the hydraulic system may lose functionality in certain operating conditions
Solution Approach 1:
The system dynamically switches between two control modes based on the operating range: in the first operating range, the electric motor maintains constant rotational speed while the control valve dynamically adjusts hydraulic flow; in the second operating range, the electric motor dynamically varies its rotational speed. This dynamic adaptation ensures the hydraulic system maintains full functionality across all operating conditions while minimizing noise in the first range.
Solution Approach 2:
The system changes the control parameter from electric motor rotational speed to control valve displacement for the first operating range, thereby reducing noise. For the second operating range, the system switches to varying electric motor rotational speed to provide higher operation speeds when needed. This parameter change allows the system to optimize between noise reduction and performance.
3Productivity
If the hydraulic system uses high pressure to enable higher operation speed, then productivity increases, but the noise level and energy consumption increase
Solution Approach 1:
The system replaces direct mechanical speed control with an electronically controlled system that uses a control valve to regulate hydraulic flow. This allows the electric motor to operate at constant speed while still achieving variable operation speeds through electronic control of the control valve, thereby reducing noise while maintaining productivity.
Solution Approach 2:
The system changes the control parameter from electric motor rotational speed to control valve displacement for the first operating range, thereby reducing noise. For the second operating range, the system switches to varying electric motor rotational speed to provide higher operation speeds when needed. This parameter change allows the system to optimize between noise reduction and performance.
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
The system significantly reduces noise variations and maintains hydraulic system functionality by controlling electric motor speed and fluid flow, enabling quieter operation without compromising performance.
Implementation Method 1
an electric motor (5) to power a working hydraulic pump (13)
Implementation Method 2
a working hydraulic pump (13) arranged to provide a flow of hydraulic fluid
Implementation Method 3
an electronically controlled control valve (25) for controlling a flow of hydraulic fluid from the pump
Data Source
Figure 1
Figure 2
Figure 3a~3c
AI summary
The invention relates to an electrically powered hydraulic system (1) for a working machine (3), the electrically powered hydraulic system comprises: an electric motor (5) to power a working hydraulic pump (13) to operate at least one hydraulic function (7) of the working machine. A flow of hydraulic fluid generated by the hydraulic pump is controlled by the operation rotational speed of the electric motor (5). An electronically controlled control valve (25) for controlling the flow of hydraulic fluid from the pump to the at least one hydraulic function. An operator input device (17, 19, 21) for controlling the at least one hydraulic function, wherein the operator input device is operable in at least two operating ranges (30, 32). An electronic control unit (11) configured to: when the operator input device is in a first operating range, maintain the electric motor at a constant rotational speed, and control a variation in flow of hydraulic fluid to the hydraulic function with the electronically controlled control valve, and when the operator input device is in a second operating range, control a variation in flow of hydraulic fluid by varying the electric motor rotational speed and by controlling the control valve, according to displacement of the operator input device.