Variable Displacement Pump Hydraulic System for Work Vehicles
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Solution Overview
Problem
Conventional hydraulic systems for work vehicles face inefficiencies in energy usage and operability, particularly due to the use of fixed displacement pumps, which lead to excessive oil supply during high engine speeds and restrict concurrent operation of power steering and elevation/rolling actuating devices, resulting in energy waste and limited operational flexibility.
Innovation Solution
A hydraulic system employing a variable displacement pump with an actuator-regulated discharge rate, preferential and non-preferential flow-dividing valves, and electromagnetic proportional control valves to optimize oil distribution among hydraulically operated devices, allowing concurrent actuation while minimizing energy waste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a fixed displacement pump is used to secure sufficient oil flow rate for power steering and elevation/rolling devices at low engine speeds, then the oil flow rate requirement is met, but energy is wasted and oil temperature increases at high engine speeds
Solution Approach 1:
The patent applies a variable displacement pump instead of a fixed displacement pump, allowing the pump's discharge rate to be dynamically adjusted based on engine speed and actual hydraulic demand. This enables the system to maintain sufficient oil flow at low speeds while reducing flow at high speeds to eliminate energy waste and prevent oil overheating.
Solution Approach 2:
The system changes the operational parameters of the pump by using a variable displacement mechanism that adjusts the discharge rate according to actual needs. The control unit modifies pump parameters (discharge rate) based on engine speed and hydraulic device requirements, optimizing energy efficiency across different operating conditions.
2Reliability
If a fixed displacement pump supplies preferential oil flow to the power steering device during steering operations, then power steering operation is ensured, but concurrent elevation operation becomes impossible
Solution Approach 1:
The variable displacement pump dynamically adjusts oil flow distribution based on real-time operational demands. During steering operations, the pump increases discharge rate to ensure power steering receives sufficient oil, while simultaneously allowing elevation devices to operate by coordinating flow distribution through control valves, enabling concurrent operations that were impossible with fixed displacement pumps.
Solution Approach 2:
The hydraulic system achieves multi-functionality by enabling concurrent operation of power steering and elevation/rolling devices through the variable displacement pump's ability to satisfy multiple hydraulic demands simultaneously. The system can perform steering, elevation, rolling, or any combination of these functions without mutual interference.
3Adaptability or versatility
If the discharge rate of the hydraulic pump is increased to allow concurrent actuation of elevation and rolling devices, then operational flexibility is improved, but energy consumption increases
Solution Approach 1:
The variable displacement pump adjusts its discharge rate parameter dynamically based on actual hydraulic demands. When multiple devices (elevation and rolling) need to operate concurrently, the pump increases flow only to the extent necessary, rather than maintaining a constantly high discharge rate. This optimizes energy consumption while preserving full operational flexibility.
Data Source
AI summary
A hydraulic system for a work vehicle is disclosed. A preferential flow-dividing valve supplies a fixed amount of oil discharged from a variable displacement pump preferentially to a preferential hydraulic oil section and a surplus oil flow from the pump to a non-preferential hydraulic oil section. A plurality of electromagnetic proportional control valves are provided in the non-preferential hydraulic oil section for controlling oil flows relative to a plurality of hydraulically operated devices provided in the non-preferential hydraulic oil section. A necessary flow rate calculating module calculates a necessary oil flow rate in each of the preferential hydraulic oil section and the non-preferential hydraulic oil section based on a preferential oil flow rate of the preferential flow-dividing valve supplied to the preferential hydraulic oil section and an amount of current distributed to each of the plurality of electromagnetic proportional control valves in the non-preferential hydraulic oil section.