Agricultural PTO Engine Speed Control for Periodic Torque Peaks
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Solution Overview
Problem
Agricultural vehicles experience significant slowdowns and driveline jerks due to periodic resistant torque peaks generated by operating machines like balers, which traditional compensation methods, such as using a CVT, can compromise system reliability.
Innovation Solution
An engine control strategy that predicts future resistant torque peaks and automatically adjusts the prime mover's rotation speed with a temporary increase, synchronized with the expected torque peaks, using the vehicle's inertia and fuel system to compensate for these fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional engine control strategies are used, then the engine operates at a predetermined speed, but the vehicle experiences noticeable slowdowns and driveline jerks due to periodic resistant torque peaks from the baler
Solution Approach 1:
The control unit proactively increases fuel injection quantity before the expected occurrence of resistant torque peaks, based on detected frequency and phase patterns. This preliminary action prevents speed drops before they happen, ensuring smooth operation and operator comfort without requiring reactive corrections.
Solution Approach 2:
The system continuously monitors the baler's resistant torque characteristics, detects frequency and phase of torque peaks, and uses this feedback to dynamically adjust fuel injection timing and quantity. This closed-loop feedback enables the engine to adapt to periodic loads while maintaining stable operation.
2Speed
If the transmission reacts to variations in prime mover speed, then it attempts to compensate for slowdowns, but the transmission is unable to react promptly enough to the periodic torque peaks
Solution Approach 1:
Instead of waiting for speed drops to occur and then reacting, the system predicts upcoming resistant torque peaks based on detected frequency and phase patterns and increases fuel injection in advance. This eliminates the problematic reaction time delay inherent in transmission-based compensation.
3Adaptability or versatility
If the accelerator lever position is used for speed control, then the operator can set a predetermined speed, but the engine speed fluctuates during transient operations when the operator acts on the lever
Solution Approach 1:
The control unit continuously monitors accelerator lever position and uses this feedback to distinguish between operator speed commands and transient fluctuations. By detecting the frequency and phase of resistant torque peaks, the system can maintain stable engine speed during transients while still responding to deliberate operator speed changes.
Data Source
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AI summary
Engine control method of an agricultural vehicle, the method comprising a first process for detecting a succession of resistant torque peaks (FP) applied to a PTO of the agricultural vehicle and calculation of a frequency value and a phase value of said succession, a second process for compensating, at least partially, future resistant torque peaks, foreseen on the basis of said frequency and phase values, by means of requests for temporary engine rotation speed increase (SR), wherein in each temporary engine rotation speed increase request is circa contemporary to each of said future resistant torque peaks.