Hydraulic Pump Dummy Load for Exhaust Filter Regeneration
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Solution Overview
Problem
The existing hydraulic drive systems for construction machines face challenges in efficiently regenerating diesel particulate filters within exhaust gas purification devices without interfering with actuator operations, leading to potential deterioration in operability and increased costs due to complex control mechanisms and high-cost components.
Innovation Solution
The system employs first and second selector valves to manage load sensing control, allowing for dummy load pressure to be applied when actuators are not in use, thereby increasing the absorption torque of the hydraulic pump and ensuring efficient filter regeneration without actuator operation interference, using existing pressure sources and low-cost selector valves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If pump output power increasing control is performed to raise exhaust gas temperature for filter regeneration, then the exhaust gas temperature increases and filter regeneration is enabled, but the actuator operations may be interfered with and operability deteriorates
Solution Approach 1:
The control system is segmented into distinct operational modes: normal mode for actuator operations and regeneration mode for filter maintenance. The selector valve physically separates these modes by routing control signals to different pathways, allowing independent optimization of each function without interference between them.
Solution Approach 2:
The system dynamically switches between different control configurations based on operational requirements. The selector valve enables transition between load sensing control (for normal operations) and dummy load pressure application (for regeneration), making the control system adaptable to different operational states.
2Adaptability or versatility
If complex control mechanisms are used to manage both actuator operations and filter regeneration, then both functions can be controlled, but the device complexity increases and costs rise
Solution Approach 1:
The selector valve serves multiple functions: it acts as a mode switch between normal operation and regeneration, a pressure source selector between actual load pressure and dummy load pressure, and a control signal router. This multi-functionality reduces the need for separate dedicated components for each control aspect.
Solution Approach 2:
The selector valve acts as an intermediary component that mediates between the control device and the hydraulic pump, allowing flexible switching between different control strategies without requiring complex reconfiguration of the entire hydraulic system.
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 enables efficient filter regeneration while maintaining actuator performance and reducing operational costs by eliminating interference between actuator operations and pump output power increasing control, utilizing existing pressure sources and low-cost selector valves.
Implementation Method 1
the oxidation catalyst inside the exhaust gas purification device is activated, the deposits on the filter (filter deposits) are combusted
Implementation Method 2
the exhaust gas temperature rises, the oxidation catalyst inside the exhaust gas purification device is activated, the deposits on the filter (filter deposits) are combusted
Implementation Method 3
the delivery pressure of the hydraulic pump becomes higher than the maximum load pressure of a plurality of actuators by a target differential pressure
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A hydraulic drive system executing the load sensing control is designed to be capable of efficiently combusting and removing filter deposits inside an exhaust gas purification device (42) by pump output power increasing control when there is no actuator operation, eliminating interference between the actuator operation and the pump output power increasing control even when they are performed at the same time, and achieving these effects with ease and at a low cost. The hydraulic drive system comprises: a solenoid selector valve (46) which selects between tank pressure and delivery pressure of a pilot pump (30) upstream of an engine revolution speed detecting valve (13) and outputs the selected pressure to a shuttle valve (45) ; and a solenoid selector valve (48) which is arranged in a line (12b) leading the output pressure of a differential pressure reducing valve (11) to an LS control valve (17b) and selects between enabling and disabling of the load sensing control. When the exhaust gas purification device (42) needs regeneration, a controller (49) executes switching to make the solenoid selector valve (46) output the delivery pressure of the pilot pump (30) as dummy load pressure and to make the solenoid selector valve (48) disable the load sensing control.