Electric Work Vehicle Hydraulic Pump Control for Steering and Actuators
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric work vehicles face inefficiencies in electric energy consumption due to constant operation of a shared hydraulic pump for power steering and hydraulic services, leading to suboptimal energy usage and reduced efficiency.
Innovation Solution
A method to manage the hydraulic circuit by activating the hydraulic pump at a speed proportional to the maximum of the steering wheel rotation speed and the control lever deflection, with a minimum speed based on hydraulic oil temperature, ensuring efficient activation only when necessary.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the hydraulic pump is kept constantly in operation to guarantee hydraulic flow to the power steering, then the power steering performance is maintained, but the electric energy consumption increases
Solution Approach 1:
The hydraulic pump operates dynamically with variable rotational speed rather than constant operation. The control unit adjusts the pump speed based on real-time steering wheel rotation speed signals, activating the pump only when steering input is detected and deactivating it when steering is not required, thus maintaining performance while reducing energy consumption
Solution Approach 2:
The system changes the operational parameters of the hydraulic pump by adjusting its rotational speed according to steering demands. The pump speed is proportional to the steering wheel rotation speed, allowing the system to adapt power delivery to actual needs and avoid unnecessary energy consumption during idle periods
2Use of energy by moving object
If the electric pump is switched off when hydraulic actuators are not in use, then electric energy is saved, but the power steering may not receive adequate hydraulic flow
Solution Approach 1:
The hydraulic system is segmented into two independent pathways: one dedicated to power steering and another to hydraulic actuators. The single electric pump can selectively supply hydraulic flow to either or both systems based on operational needs, allowing independent control and avoiding the need for separate pumps while ensuring both functions receive adequate flow when required
Solution Approach 2:
The control unit acts as an intermediary that monitors both steering wheel input and actuator valve positions, then intelligently activates the hydraulic pump only when needed for either function. This intermediary control ensures that hydraulic flow is available to both power steering and actuators without continuous pump operation, resolving the conflict between energy saving and flow availability
3Reliability
If a separate hydraulic pump is provided for power steering, then flexibility and reliability of power steering are improved, but the efficiency from an electrical point of view is reduced
Solution Approach 1:
A single electric hydraulic pump is designed to perform multiple functions: supplying hydraulic flow to both the power steering system and the hydraulic actuators. This universal pump replaces what would traditionally require two separate pumps, reducing overall system complexity and energy consumption while maintaining the reliability and flexibility of power steering through intelligent control that prioritizes steering flow when needed
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
Optimizes electric energy consumption by activating the hydraulic pump only when needed, maintaining performance without compromising vehicle functionality.
Implementation Method 1
a hydraulic pump (EHP) driven in rotation by an electric motor
Implementation Method 2
an oil flow generated by the hydraulic pump is regulated by means of an open center proportional directional valve
Data Source
Figure 1~2
Figure 3
AI summary
Method of managing a hydraulic circuit of an electric work vehicle (EV), the hydraulic circuit (HC) comprising an electric hydraulic pump (EHP) configured to supply a hydraulic power steering (SV) and at least one hydraulic actuator (HA) of a work member (A, B) of the electric work vehicle, the method comprising a procedure for calculating a first speed value of the hydraulic pump as a function of an actuation speed of said steering wheel and at least a second rotation speed value of the hydraulic pump as a function of a deviation of said second interface means (J, R) with respect to a relative release position, and regulating the hydraulic pump speed according to the greater value between said first and at least second speed value.