Heavy Vehicle Transmission Shift Adaptation for PTO Load
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Solution Overview
Problem
Automated transmission control strategies for heavy commercial vehicles fail to account for the significant power consumption and load imposed by power take-off (PTO) systems, leading to performance degradation and difficulty in adjusting transmission when the PTO is engaged, especially during motion.
Innovation Solution
A method to determine the operational state of the PTO by comparing torque available for the drive wheels to total engine torque, and adjust gear-shift events to occur at higher engine speeds when a PTO load is detected, ensuring consistent drive wheel acceleration and maintaining vehicle performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the transmission control routine does not account for PTO load, then the control strategy remains simple and preprogrammed, but the transmission performance degrades when PTO is operational
Solution Approach 1:
The transmission control routine dynamically adapts its shifting strategy based on detected PTO load conditions. The system transitions from static preprogrammed routines to dynamic control that modifies shift points and timing based on real-time PTO operational status, resolving the contradiction between maintaining simple control and achieving reliable performance under varying loads
Solution Approach 2:
The control system changes key parameters such as shift points and engine speed targets based on detected PTO load conditions. By adjusting these parameters dynamically, the system maintains optimal transmission performance whether the PTO is operational or not, without requiring completely complex control architecture
2Speed
If the engine speed is increased to compensate for PTO torque consumption during gear shifts, then the drive wheel acceleration remains consistent, but the engine operates at higher speeds consuming more energy
Solution Approach 1:
The system performs preliminary detection of PTO load conditions before executing gear shift commands. By anticipating the PTO's torque consumption in advance, the control routine pre-adjusts engine speed targets and shift timing to compensate for the expected load, ensuring consistent acceleration while avoiding excessive energy consumption through precise rather than excessive compensation
3Reliability
If the transmission shifting strategy is adapted in real-time based on PTO load detection, then the transmission performance is maintained, but the control system complexity increases
Solution Approach 1:
The system implements feedback mechanisms that monitor engine torque, engine speed, and vehicle operating conditions to detect PTO load. This feedback loop enables the control routine to automatically adapt shifting strategies based on actual PTO operational status, maintaining transmission performance through intelligent adaptation rather than complex hardware modifications
Data Source
AI summary
Method and arrangement for adjusting shift characteristics of a transmission of a heavy vehicle. A heavy vehicle is operated and that is powered by an internal combustion engine equipped with an automated manual transmission and a power take off. The power take off, when operating, imposes a torque-consuming load on the engine. Operation of the power take off is detected when the engine of the vehicle is in a power mode. At least one gear-shift event is adapted to occur at a higher engine speed when power take off operation is detected than when power take off operation is not detected. The gear-shift event is affected at an engine speed that is approximately five to twenty-five percent higher than when power take off operation is not detected. The gear-shift event may be an up-shift to a lower ratio gear engagement or a down-shift to a higher ratio gear engagement.