Adaptive Mower Engine Speed Control Using Traction Feedback
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Solution Overview
Problem
Existing grass mowing machines with internal combustion engines face challenges in maintaining optimal engine speed to meet varying power requirements across different terrains and conditions without increasing fuel consumption and noise, and require sensors to measure hydraulic pressures for precise control.
Innovation Solution
An adaptive engine speed control system that adjusts engine speed based on traction feedback and hydraulic mowing circuit loads, eliminating the need for additional sensors, and allowing automatic adaptation to terrain and load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the engine runs at maximum speed to meet power requirements in sloping terrain or wet grass conditions, then power output is sufficient, but fuel consumption increases and noise levels rise
Solution Approach 1:
The engine speed is made dynamic rather than fixed, allowing it to adapt automatically to varying load conditions. The controller continuously monitors traction feedback from the hydrostatic drive circuit and adjusts engine speed in real-time, enabling the engine to operate at lower speeds during light loads and increase speed only when power demands increase due to terrain or grass conditions.
Solution Approach 2:
The system employs feedback control by monitoring the traction feedback signal from the hydrostatic traction drive circuit. This feedback mechanism allows the controller to detect changes in power requirements caused by terrain slope, grass moisture, or other operating conditions and automatically adjust engine speed accordingly, preventing unnecessary fuel consumption and noise generation.
2Speed
If the engine runs at maximum speed to maintain ground speed in sloping terrain, then ground speed is maintained, but noise levels increase
Solution Approach 1:
The engine speed is dynamically adjusted based on actual power demands rather than maintained at a fixed maximum speed. The controller modulates engine speed to match the power required to maintain desired ground speed under varying conditions, thereby reducing noise generation during periods when full power is not needed.
Solution Approach 2:
The feedback signal from the hydrostatic traction drive circuit provides real-time information about the power required to maintain ground speed. The controller uses this feedback to adjust engine speed only when necessary, minimizing noise pollution while ensuring ground speed is maintained when terrain conditions demand it.
3Measurement precision
If sensors are added to measure hydraulic pressure for precise power requirement detection, then power control precision improves, but device complexity increases
Solution Approach 1:
The system uses existing components and signals to achieve power requirement detection without adding dedicated pressure sensors. The controller leverages the traction feedback signal already present in the hydrostatic traction drive circuit, allowing the system to self-determine power requirements using information already available in the control architecture.
Solution Approach 2:
The existing hydrostatic traction drive circuit and its feedback signal serve multiple functions: they provide both traction control and power requirement information for engine speed adjustment. This multi-functionality eliminates the need for separate pressure sensors, maintaining measurement capability while reducing device complexity.
Data Source
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AI summary
An adaptive engine speed control system (100) for a grass mowing machine (102) having an internal combustion engine (104), a hydrostatic traction drive circuit (106) and a hydraulic mowing circuit (108) for operating a plurality of cutting units. A controller provides a traction feedback output signal (202) if the grass mowing machine is moving at an actual ground speed that is below a pedal based desired ground speed, and uses the traction feedback output signal to command the internal combustion engine to an increased speed above a pedal based engine speed (204) control range.