Excavator Pump Flow Control for Engine Torque Lag
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Solution Overview
Problem
Existing excavator control systems fail to account for the delay in the rise of actual engine torque, leading to a risk of the oil hydraulic pump's absorbing torque exceeding the engine's actual torque, causing engine speed to decrease.
Innovation Solution
Incorporating a processor and memory system that controls the flow rate of hydraulic oil discharged by the oil hydraulic pump, delaying its response until the engine's actual torque rises to match the increased load, thereby preventing the absorbing torque from exceeding the engine's torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the oil hydraulic pump responds immediately to increased engine load, then the system responds quickly to operator input, but the absorbing torque exceeds the actual torque causing engine speed to decrease
Solution Approach 1:
The control system delays the oil hydraulic pump's response to increased engine load until the actual torque has risen to match the load. This preliminary waiting action prevents the pump from drawing excessive torque before the engine can deliver it, thereby preventing engine speed decrease while still maintaining eventual system responsiveness.
2Productivity
If the oil hydraulic pump increases discharge rate immediately when load increases, then productivity improves, but fuel efficiency decreases due to engine speed variations
Solution Approach 1:
The control system continuously monitors engine load and actual torque, using this feedback to determine the appropriate timing for increasing the oil hydraulic pump's discharge rate. By baseing the pump response on real-time engine state feedback rather than immediate operator input, the system maintains productivity while avoiding fuel efficiency degradation from premature torque demands.
Data Source
AI summary
An excavator may include a lower traveling body; an upper turning body pivotally installed to the lower traveling body; an engine installed in the upper turning body; a main pump driven by the engine; and a processor and a memory that stores program instructions causing the processor to control a flow rate of hydraulic oil discharged by the main pump. The program instructions can cause the processor to, when a load of the engine increases, delay a response of the main pump 14 until an actual torque of the engine rises up to a level corresponding to the load of the engine.