Hydraulic Drive Engine Stopping Control for Regeneration
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Solution Overview
Problem
Hydraulic drive devices for construction machines may fail to adequately perform regeneration control of exhaust filters and warm-up operations when the engine is stopped after a predetermined period, leading to incomplete regeneration and insufficient warm-up of hydraulic oil.
Innovation Solution
A hydraulic drive device with a control signal judging unit that determines whether the discharge rate of the variable displacement hydraulic pump is at or below a predetermined lower limit, allowing for reliable engine stopping only when appropriate conditions are met for regeneration control and warm-up operations to be completed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine is stopped after a predetermined period when the gate lock lever is in the open position, then fuel consumption is reduced, but regeneration control of the exhaust filter is not sufficiently performed
Solution Approach 1:
The control signal judging unit continuously monitors the control signal from the discharge rate control unit and provides feedback to determine whether engine stopping conditions are met. This feedback mechanism ensures that the engine is only stopped when both the time condition and the discharge rate condition are satisfied, preventing premature stopping that would compromise regeneration control
Solution Approach 2:
The system performs preliminary judgment of the control signal value before allowing engine stopping. By checking whether the control signal indicates a discharge rate at or below the lower limit before the predetermined time elapses, the system ensures that regeneration control and warm-up operations are completed beforehand, preventing insufficient regeneration while still enabling fuel savings
2Loss of energy
If the engine is stopped after a predetermined period when the gate lock lever is in the open position, then fuel consumption is reduced, but warm-up operation is not sufficiently completed
Solution Approach 1:
The control signal judging unit continuously monitors the control signal from the discharge rate control unit and provides feedback to determine whether engine stopping conditions are met. This feedback mechanism ensures that the engine is only stopped when both the time condition and the discharge rate condition are satisfied, preventing premature stopping that would compromise warm-up operation
Solution Approach 2:
The system performs preliminary judgment of the control signal value before allowing engine stopping. By checking whether the control signal indicates a discharge rate at or below the lower limit before the predetermined time elapses, the system ensures that warm-up operation is completed beforehand, preventing insufficient warm-up while still enabling fuel savings
3Temperature
If the discharge rate of the variable displacement hydraulic pump is controlled to be higher than the lower limit during warm-up operation, then hydraulic oil is warmed effectively, but engine stopping cannot be performed even when the gate lock lever is in the open position
Solution Approach 1:
The system dynamically adjusts the discharge rate control based on the operational phase. During warm-up operation, the discharge rate is maintained above the lower limit to ensure effective heating. However, the control signal judging unit can detect when the control signal indicates a discharge rate at or below the lower limit, allowing the system to transition to engine stopping mode when appropriate conditions are met
Solution Approach 2:
The system changes the judgment parameter from purely time-based to a combination of time-based and discharge rate-based conditions. By introducing the control signal judgment that monitors discharge rate parameters, the system can distinguish between high discharge rate due to warm-up requirements versus high discharge rate due to operational needs, enabling intelligent engine stopping decisions
Data Source
AI summary
A hydraulic drive device for a construction machine includes an engine stopping unit and a discharge rate control unit. The engine stopping unit stops the engine when a predetermined state of the construction machine has continued for a predetermined period of time. The discharge rate control unit controls a discharge rate control pressure being input to the regulator, when an exhaust emission control device performs regeneration control, or performs warm-up control, and the gate lock lever is in the open position.