Electronic Engine Speed Control for Grass Mowers
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Solution Overview
Problem
Current engine speed control systems for grass mowing machines are complex and separate from hydrostatic transmission controls, leading to inefficient fuel use, excessive noise, and vibration, as well as inadequate engine speed adjustment when using attachments, resulting in suboptimal operation.
Innovation Solution
An electronic engine speed control system that integrates inputs from pedal and hand lever sensors, a microcontroller, and sensors for engine speed, temperature, and PTO engagement to automatically adjust engine speed based on operating conditions, ensuring optimal speed and reducing unnecessary energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If engine speed control and hydrostatic transmission control are operated separately, then the operator can control each function independently, but the control system complexity increases and fuel efficiency decreases
Solution Approach 1:
The patent combines engine speed control and hydrostatic transmission control into a single integrated system. The foot pedal that controls hydrostatic transmission also controls engine speed through the microcontroller, which reads the pedal position sensor and automatically adjusts the engine speed actuator accordingly. This merging eliminates the need for separate controls while maintaining full functionality.
Solution Approach 2:
The foot pedal serves dual functions: controlling hydrostatic transmission speed and controlling engine speed. The microcontroller system provides universal control by monitoring the same pedal position input to manage both the transmission and engine, making one control element perform multiple functions.
2Ease of operation
If the engine is run at fast idle to simplify operation, then the operator can control vehicle speed with transmission only, but fuel consumption increases and noise and vibration increase
Solution Approach 1:
The system uses feedback from the pedal position sensor to continuously monitor the operator's desired transmission speed and automatically adjusts engine speed accordingly. The microcontroller reads the pedal position and sends appropriate signals to the engine speed actuator, creating a closed-loop control system that eliminates the need for manual engine speed adjustment.
Solution Approach 2:
The engine speed control system is self-regulating based on transmission speed requirements. The microcontroller automatically adjusts engine speed without operator intervention by processing pedal position input and controlling the engine speed actuator, making the system self-managing rather than requiring manual fast idle setting.
3Loss of energy
If the engine speed is not sufficiently increased when PTO is engaged, then fuel consumption is reduced, but the attachments cannot operate properly under heavy load
Solution Approach 1:
The PTO clutch position sensor provides feedback to the microcontroller about PTO engagement status. When the sensor detects PTO engagement, the microcontroller automatically increases engine speed by adjusting the engine speed actuator, ensuring sufficient power for attachments without requiring manual operator intervention.
Solution Approach 2:
The system takes preliminary action by detecting PTO engagement through the clutch position sensor and proactively increasing engine speed before the attachment encounters heavy load. This anticipatory adjustment ensures the engine is already at the appropriate speed when the attachment begins working, preventing power deficiency.
Data Source
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AI summary
An electronic engine speed control system (100) for a grass mowing machine powered by an internal combustion engine includes a microcontroller (102) providing an output signal to an engine speed actuator (114) for the engine, a pedal position sensor (122) connected to a foot pedal and providing a voltage input signal to the microcontroller (102) based on the position of the foot pedal, a PTO clutch switch or sensor (132) providing a signal input to the microcontroller (102) indicating if a PTO clutch is engaged, and a lever position sensor (124) connected to a hand lever and having a range of positions including an Automatic mode position and a plurality of Manual mode positions. The hand lever position sensor (124) provides a voltage input signal to the microcontroller (102) in the Automatic mode position such that the microcontroller (100) output to the engine speed actuator (114) is related to the voltage inputs from the pedal position sensor (122) and PTO clutch switch or sensor (132), and provides a voltage input signal to the microcontroller (102) in a range of Manual mode positions such that the microcontroller (102) output to the engine speed actuator (114) is related to the voltage input from the lever position sensor (124).