Fluid Delivery System Parasitic Load Reduction
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Solution Overview
Problem
The existing hydraulic systems in machines, such as articulated trucks, face issues with parasitic loads on hydraulic accumulators due to differential pressure demands, leading to low brake pressure warnings and noise from inverse shuttle valves, which reduces valve life and efficiency.
Innovation Solution
A fluid delivery system that includes a pump, accumulators, check valves, and control units to manage fluid flow and pressure, with the auxiliary system positioned upstream of the check valve to limit parasitic loads and reverse fluid flow, using valves and orifices to regulate pressure and flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the differential is hydraulically coupled to the hydraulic circuit upstream of the inverse shuttle valve and accumulators, then the differential can receive hydraulic power, but parasitic load is induced on the accumulators which are primarily employed for powering brakes
Solution Approach 1:
The system is divided into separate hydraulic circuits: a braking circuit with accumulators dedicated to brakes, and an auxiliary circuit for the differential. This segmentation prevents the differential from drawing pressure from the brake accumulators, eliminating parasitic loads while ensuring both systems have adequate hydraulic power.
Solution Approach 2:
A check valve is introduced as an intermediary component in the auxiliary line upstream of the inverse shuttle valve. This check valve allows the auxiliary system to receive pressure from the pump during normal operation but prevents reverse flow from the accumulators through the inverse shuttle valve, thereby protecting the brake pressure while still enabling differential operation.
2Device complexity
If the inverse shuttle valve is designed for allowing fluid flow in one direction towards the hydraulic accumulators, then the valve structure is simple, but reverse flow from accumulators towards differential results in vigorous movement of valve element with respect to valve seat causing noise and reduced valve life
Solution Approach 1:
A check valve is placed in the auxiliary line upstream of the inverse shuttle valve to act as a mediator that permits forward flow to the accumulators but blocks reverse flow. This prevents the vigorous movement of the inverse shuttle valve element that causes noise and wear, while maintaining the simple one-way design of the inverse shuttle valve itself.
Solution Approach 2:
The check valve provides preliminary anti-action by preventing reverse flow before it can reach the inverse shuttle valve. This anticipatory blocking action stops the harmful reverse flow condition from occurring, thereby preventing noise and extending valve life without modifying the inverse shuttle valve structure.
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 system reduces parasitic loads on accumulators, minimizes noise and valve wear, and ensures efficient hydraulic power delivery to both braking and auxiliary systems, improving overall system efficiency and extending component life.
Implementation Method 1
arranged upstream of a check valve in the main line to limit a flow of the fluid from each of the plurality of accumulators to the auxiliary system
Implementation Method 2
A fluid delivery system that includes a pump, accumulators, check valves, and control units to manage fluid flow and pressure
Implementation Method 3
A fluid delivery system that includes a pump, accumulators, check valves, and control units to manage fluid flow and pressure
Data Source
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Figure 3
AI summary
A system (202) for delivering fluid in a machine (102) is provided. The system (202) includes a pump (208), a first valve (214) disposed downstream of the pump (208), a check valve (220) disposed downstream of the first valve (214), at least one accumulator (216, 218) disposed downstream of the check valve (220), and an auxiliary system (204) disposed upstream of the check valve (220). The system (202) further includes a control unit (232) configured to receive a signal indicative of a fluid demand from the auxiliary system (204). The control unit (232) is also configured to selectively control the first valve (214) in a first position (P1) to limit flow of the fluid from the pump (208) to the auxiliary system (204), and in a second position (P2) to allow flow of the fluid from the pump (208) to the auxiliary system (204) based, at least in part, on the received signal. The check valve (220) limits flow of a fluid from the at least one accumulator (216, 218) to the auxiliary system (204).