Hydraulic Pilot Solenoid Valve Cleaning Before Engine Start
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Solution Overview
Problem
Existing technologies for preventing silting in solenoid valves are constrained by limitations that prevent sufficient removal of foreign matters, leading to potential valve sticking and hydraulic actuator malfunctions.
Innovation Solution
A work machine with a controller that assesses engine stoppage to apply a drive current to the solenoid valve, allowing effective removal of foreign matters without influencing hydraulic actuator operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the movement amount of the spool of a solenoid valve is increased to remove foreign matters, then the effectiveness of foreign matter removal is improved, but the hydraulic actuator may be undesirably actuated
Solution Approach 1:
The solenoid valve is actuated during the engine stoppage period before engine start, when no hydraulic actuator should be operating. This preliminary action allows the spool to move sufficiently to remove foreign matters without causing undesirable actuation of hydraulic actuators, as the engine and hydraulic system are not yet operational.
2Reliability
If a drive current is applied to the solenoid valve during engine operation, then foreign matters can be removed, but the engine operation time is reduced and productivity is lowered
Solution Approach 1:
The silting preventing process is performed during the engine stoppage period before start, utilizing otherwise wasted time. This approach maintains solenoid valve reliability by removing foreign matters without reducing productive engine operation time, as the process occurs during a non-productive period anyway.
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
Effectively removes foreign matters from solenoid valves without disrupting hydraulic actuator functions, preventing valve sticking and ensuring smooth operation.
Implementation Method 1
a solenoid valve that reduces a pressure of the hydraulic working fluid supplied from the second pump to generate a pilot pressure for operating the control valve
Implementation Method 2
a rotation speed sensor that senses a rotation speed of the engine
Implementation Method 3
apply a drive current to the solenoid valve to drive the solenoid valve when it is assessed that the current application condition is established
Data Source
AI summary
A work machine includes: a first pump and a second pump that are driven by an engine; a hydraulic actuator driven by a hydraulic working fluid supplied from the first pump; a control valve that controls a flow of the hydraulic working fluid supplied to the hydraulic actuator; a solenoid valve that reduces a pressure of the second pump to generate a pilot pressure for operating the control valve; a controller that controls the solenoid valve; an engine operating section that enables operation for activating the engine; and a rotation speed sensor that senses a rotation speed of the engine. The controller applies a drive current to the solenoid valve to drive the solenoid valve when a current application condition is established, the current application condition including that it is assessed, on the basis of a sensing result of the rotation speed sensor, that the engine is in a stopped state, and including that ON operation of the engine operating section is performed in a state where activation operation is not performed by the engine operating section.