Excavation Powertrain Control System for Engine Speed Stability
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Solution Overview
Problem
Existing excavation machine control systems fail to adapt to changing loads and performance over the life of the machine, leading to engine speed fluctuations, reduced responsiveness, and inefficiencies, which affect fuel efficiency and exhaust emission efficiency.
Innovation Solution
A control system for a powertrain that includes sensors to monitor actual speed, force, and implement position, and a controller that determines closed-loop and open-loop gain values to adjust fueling based on the difference between desired and actual speed, classifying operations to optimize fueling during different segments of the excavation cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the operator sets the engine speed to a desired speed (e.g., high-idle), then the engine operates at a speed optimized for responsiveness and power, but the actual speed droops under load or shoots over the desired speed according to loading conditions, resulting in speed fluctuations
Solution Approach 1:
The control system continuously monitors actual engine speed and compares it to the desired speed, then adjusts fueling based on the difference (error signal). This closed-loop feedback mechanism corrects speed deviations caused by loading conditions, maintaining stable engine speed despite external disturbances.
Solution Approach 2:
The system dynamically changes the fueling parameter based on operating conditions and classification of the current cycle segment. By adjusting fuel delivery in response to detected speed deviations and classified operational phases, the system maintains optimal speed across varying load conditions.
2Power
If the engine speed droops under load, then the engine may not immediately produce the necessary power, but increasing fueling to compensate can result in lag or delay due to limited combustion air from turbochargers at low speeds
Solution Approach 1:
The system classifies the current operation into predefined cycle segments (dig, move-to-truck, dump, move-to-trench) and applies anticipatory fueling adjustments based on the expected loading conditions of each segment. This preliminary action prepares the engine for upcoming load changes, reducing lag and improving response time.
Solution Approach 2:
The control system acts as an intermediary between the operator's speed command and the actual engine fueling. By processing the desired speed command through classification logic and feedback mechanisms, the system mediates the response to load changes, optimizing both power delivery and response time.
3Stability of the object's composition
If the engine operates away from the desired speed to accommodate load variations, then speed stability is maintained, but fuel efficiency and exhaust emission efficiency are reduced
Solution Approach 1:
The system dynamically adjusts fueling parameters based on the classified cycle segment and detected speed deviations, allowing the engine to operate closer to the desired efficient speed while still accommodating load variations. This optimized parameter adjustment improves fuel efficiency compared to conservative speed maintenance strategies.
4Device complexity
If a simple speed control system is used, then the system complexity is low, but the system cannot adapt to changing loads and performance over the life of the machine
Solution Approach 1:
The control system segments the excavation cycle into predefined operations (dig, move-to-truck, dump, move-to-trench) and applies different control strategies to each segment. This segmentation allows the system to adapt to changing loads appropriately for each phase while maintaining manageable overall complexity through modular control logic.
Solution Approach 2:
The control system dynamically adapts its behavior based on the classified current operation and real-time speed deviations. By making the control parameters dynamic rather than static, the system achieves high adaptability to changing loads and performance conditions without requiring excessive system complexity.
Data Source
AI summary
A control system is disclosed for use with a powertrain of a machine. The control system may have a first sensor configured to generate a first signal indicative of an actual speed, a second sensor configured to generate second signal indicative of at least one of a force bearing on the machine and a position of an implement, and an interface device configured to generate a third signal indicative of a desired speed. The control system may also have a controller configured to determine a closed-loop gain value based on a difference between the actual and desired speeds, to classify a current operation of the machine based on the second signal, and to determine an open-loop gain value based on classification of the current operation. The controller may also be configured to control fueling of the machine based on a superposition of the closed-loop gain value and the open-loop gain value.