Dynamic Droop Curve Engine Speed Control
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Solution Overview
Problem
Existing engine control systems using preset droop functions struggle to optimize operator feel, engine performance, and fuel economy, as they are not adaptable to varying operating conditions.
Innovation Solution
A system that includes a governor and a controller capable of adjusting the location of a transition point on a droop curve based on the average operating load, creating a dynamic droop curve to optimize engine speed control in response to changing load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a preset droop function is used to control engine speed, then the engine speed control is stable and provides feedback to the operator, but the system cannot optimize operator feel, engine performance, and fuel economy under varying operating conditions
Solution Approach 1:
The patent implements a dynamic droop curve system where the transition point between first and second droop curves is automatically adjusted based on real-time operating conditions. The controller continuously monitors engine parameters and dynamically repositions the transition point along the load axis, allowing the droop characteristic to adapt to varying operating conditions such as different drive wheel slip conditions, thereby resolving the contradiction between adaptability and complexity
Solution Approach 2:
The system changes the parameter of the droop curve by adjusting the transition point location between different droop regions. By modifying this critical parameter based on operating conditions, the system achieves adaptability without requiring complete redesign of the control architecture, thus balancing adaptability with acceptable complexity
2Adaptability or versatility
If the transition point location on the droop curve is fixed, then the control system is simple, but the system cannot optimize engine performance and fuel economy under different average load conditions
Solution Approach 1:
The controller uses feedback from engine operating parameters to automatically adjust the transition point location. By continuously monitoring the operating state and comparing it with optimal conditions, the system self-regulates the droop curve configuration, achieving optimization under different load conditions while maintaining a relatively simple control structure through intelligent feedback mechanisms
3Ease of operation
If a single droop curve is used for all operating conditions, then the control system is simple and reliable, but the system cannot provide optimal operator feel and fuel economy across varying load conditions
Solution Approach 1:
The droop curve is segmented into two distinct regions (first droop curve and second droop curve) with different characteristics optimized for different operating conditions. The system segments the control strategy based on operating load, using a first droop characteristic for certain conditions and a second droop characteristic for others, with the transition point dynamically positioned. This segmentation allows optimization of operator feel for different conditions while keeping the overall structure manageable through clear regional differentiation
Data Source
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AI summary
A machine includes an engine and a governor operable to control an operating speed of the engine along a first droop curve such that the operating speed is a function of an operating load of the engine. The first droop curve includes a first region that defines a first slope, a second region that defines a second slope different from the first slope, and a transition point located at an intersection of the first region and the second region. The machine further includes a controller in communication with the governor. The controller is configured to determine an average operating load of the engine over a predetermined time period, adjust the location of the transition point based at least in part on the average operating load to create a second droop curve, and operate the engine based on the second droop curve.