Hydraulic Excavator Bypass Valve Control for Lower Pressure Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Hydraulic excavators face inefficiencies in fuel consumption and work efficiency due to hydraulic pressure loss when multiple actuators with different loads are operated simultaneously, as existing solutions either restrict fluid flow or fail to fully utilize pump capacity.
Innovation Solution
A hydraulic excavator design featuring a center bypass flow control valve and spool stroke limitation device, which adjusts flow rates and spool stroke amounts based on operation amounts of directional control valves to minimize hydraulic pressure loss and optimize fluid distribution between actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a restrictor is provided in the bypass line to restrict hydraulic fluid flow, then hydraulic fluid flows preferentially to the boom cylinder, but hydraulic pressure loss increases and work efficiency deteriorates
Solution Approach 1:
The patent replaces the fixed restrictor with a variable opening restrictor whose opening area changes dynamically based on operation conditions. The opening area is controlled to be smaller during initial boom raising to ensure preferential flow, and larger during subsequent phases to reduce pressure loss and improve energy efficiency.
Solution Approach 2:
The patent changes the restrictor opening area parameter from a fixed value to a variable value that adapts to different operational phases. By adjusting the opening area based on boom cylinder pressure and flow conditions, the system optimizes both speed and energy efficiency at different stages of operation.
2Loss of energy
If the restrictor opening area is increased to reduce hydraulic pressure loss, then fuel consumption decreases, but boom raising speed may be insufficient during initial operation
Solution Approach 1:
The system performs preliminary action by initially setting the restrictor opening area to a smaller value to ensure rapid boom raising at the start of operation. After the initial phase is complete, the opening area is increased to reduce pressure loss and improve fuel efficiency for subsequent operations.
Solution Approach 2:
The restrictor opening area is adjusted periodically based on operational phases - smaller opening during the initial boom raising phase, and larger opening during subsequent phases. This periodic adjustment optimizes both speed and energy efficiency at appropriate times.
3Loss of energy
If a solenoid proportional pressure reducing valve is used instead of a restrictor, then hydraulic pressure loss is reduced, but the spool stroke amount is limited and arm crowding speed decreases during maximum operation
Solution Approach 1:
The patent uses a variable opening restrictor that dynamically adjusts its opening area based on real-time operational conditions, unlike the fixed-stroke solenoid valve. This dynamic adjustment allows the system to maintain both low pressure loss and high arm crowding speed during maximum operation by optimizing the opening area according to actual flow and pressure requirements.
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 configuration reduces hydraulic pressure loss and enhances work efficiency by ensuring effective use of hydraulic fluid, thereby lowering fuel consumption and improving operational speed during simultaneous operations of multiple actuators.
Implementation Method 1
a center bypass flow control valve which limits a flow rate of hydraulic fluid passing through the center bypass line in response to an operation amount of the second operation device
Implementation Method 2
a spool stroke limitation device which limits a spool stroke amount of the second directional control valve in response to an operation amount of the first operation device in a state in which a spool stroke amount of the third directional control valve is controlled in response to an operation amount of the second operation device
Data Source
AI summary
A hydraulic excavator is provided which can suppress the fuel consumption amount and improve the work efficiency by reducing the hydraulic pressure loss generated when a plurality of hydraulic actuators different in load are operated simultaneously. The hydraulic excavator includes a center bypass flow control valve that is arranged at the most downstream of a center bypass line and limits the flow rate of hydraulic fluid passing through the center bypass line in response to the operation amount of the second operation device in a case where a second operation device is operated, and a spool stroke limitation device that, in a case where a first operation device and the second operation device are operated simultaneously, limits the spool stroke amount of a second directional control valve in response to the operation amount of the first operation device in a state in which the spool stroke amount of a third directional control valve is controlled in response to the operation amount of the second operation device.