Variable Engine Speed Control for Hydraulic System Stall Prevention
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Solution Overview
Problem
Construction machinery hydraulic systems face inefficiencies in energy use and fuel consumption due to fixed engine speed settings, leading to engine stall phenomena and excessive fuel use when sudden loads are applied, as existing technologies fail to properly reflect the dynamic characteristics of the engine.
Innovation Solution
A method for controlling the hydraulic system that adjusts engine speed within a variable range, using a controller to distribute engine horsepower between multiple pumps based on operation modes and loads, preventing engine speed from dropping below a certain threshold and optimizing fuel efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a fixed rated engine speed is set to maximize pump horsepower, then the pump can use maximum horsepower, but the engine speed drops sharply when sudden loads are applied and may fall below the rated speed causing engine stall
Solution Approach 1:
The patent applies dynamics by transitioning from a fixed rated engine speed to a variable rated engine speed that adapts to operating conditions. The controller dynamically adjusts the rated engine speed based on actual engine speed, load mode, and operation displacement to prevent engine stall while maximizing pump horsepower utilization.
Solution Approach 2:
The patent changes the parameter of rated engine speed from a fixed value to a variable value. The controller calculates a variable rated engine speed using a formula that incorporates actual engine speed, load mode factors, and operation displacement factors, allowing the system to adapt to varying load conditions and prevent engine stall.
2Power
If the rated engine speed is set high to maximize pump horsepower utilization, then the pump can operate at full capacity, but fuel consumption increases unnecessarily when full horsepower is not required
Solution Approach 1:
The system dynamically adjusts the rated engine speed based on actual operating conditions rather than maintaining a fixed high speed. The controller calculates the variable rated engine speed in real-time based on actual engine speed, load mode, and operation displacement, allowing the engine to operate at optimal speed for current conditions and reduce fuel consumption when full horsepower is not needed.
Solution Approach 2:
The patent changes the rated engine speed parameter from a constant high value to a variable value that adapts to actual load requirements. By using a calculation formula that incorporates load mode factors and operation displacement factors, the system optimizes the rated engine speed to match actual power needs, reducing unnecessary fuel consumption.
3Device complexity
If a fixed rated engine speed is used, then the control system is simple, but it cannot properly reflect the dynamic characteristics of the engine under varying loads
Solution Approach 1:
The patent implements dynamics by making the rated engine speed variable rather than fixed. The controller continuously calculates and updates the rated engine speed based on actual engine speed, load mode, and operation displacement, enabling the system to adapt to dynamic engine characteristics and varying load conditions while maintaining reasonable control complexity.
Solution Approach 2:
The patent changes the rated engine speed from a fixed parameter to a variable parameter that reflects dynamic engine characteristics. The calculation formula incorporates actual engine speed, load mode factors, and operation displacement factors, allowing the system to adapt to varying loads and engine conditions without requiring overly complex control mechanisms.
4Use of energy by moving object
If the engine speed is allowed to drop to maintain fuel efficiency, then fuel consumption decreases, but the engine may stall when a large load is suddenly applied
Solution Approach 1:
The patent changes the rated engine speed parameter dynamically based on actual operating conditions. When sudden loads are applied, the controller calculates a higher variable rated engine speed using the formula that incorporates actual engine speed and load mode factors, preventing engine stall. When loads are stable, the system allows engine speed to optimize for fuel efficiency.
Solution Approach 2:
The system uses feedback by continuously monitoring actual engine speed, load mode, and operation displacement to calculate and adjust the variable rated engine speed. This feedback mechanism allows the controller to respond to sudden load changes and prevent engine stall while maintaining fuel efficiency during stable operating conditions.
Data Source
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AI summary
The present disclosure relates to a method for controlling a hydraulic system of construction machinery. The method for controlling the hydraulic system of construction machinery according to the present disclosure includes an engine speed (rpm) prediction step S160, in which a variable rated engine speed, which varies within a range larger than a fixed rated engine speed and smaller than a high idle engine speed for the fixed rated engine speed and a virtual engine speed, which is to be input later, are predicted to output a virtual engine speed value predicted before an actual engine speed is input. Accordingly, when an operation load is applied, pump torque may initially have a margin, and even though an engine speed is decreased due to the operation load, it is possible to prevent an engine speed decrease phenomenon in which the engine speed becomes remarkably smaller than the rated engine speed.