Heavy Vehicle Transmission Control for Speed Sensitive PTO
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current transmission control routines for heavy commercial vehicles do not account for engine speeds that could damage speed-sensitive power take-off (PTO) loads, leading to potential equipment failure and safety risks, as they often require engine speeds to exceed PTO speed limits, especially when PTOs impose significant loads on the engine.
Innovation Solution
Implementing a method to limit engine speed to below the maximum allowable PTO operating speed by communicating the PTO speed limit to the transmission control unit, ensuring that gear shifts do not exceed this limit, and using this information to control engine speed and gear selection to prevent over-speeding of the PTO.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the transmission control routine allows engine speed to exceed PTO speed limits to optimize vehicle performance, then vehicle productivity is improved, but the PTO equipment reliability deteriorates due to potential over-speeding damage
Solution Approach 1:
The transmission control unit is pre-programmed with PTO speed limit information before operation begins. The system proactively prevents over-speeding by evaluating gear shift requests against the PTO speed limit in advance, rather than reacting after damage occurs. This preliminary constraint ensures the PTO never exceeds its safe operating speed while allowing the vehicle to maintain optimal performance within those boundaries.
2Reliability
If the transmission control unit restricts engine speed to stay below PTO speed limits, then PTO reliability is improved, but vehicle productivity deteriorates due to limited engine speed range
Solution Approach 1:
The system dynamically adjusts the effective speed limit based on PTO engagement status. When the PTO is disengaged, the transmission control unit allows engine speeds above the PTO limit, restoring full vehicle performance capability. When the PTO is engaged, the limit is enforced to protect the equipment. This dynamic behavior eliminates the need for permanent productivity restrictions while maintaining reliability when needed.
Solution Approach 2:
The system changes the operational parameter (engine speed limit) based on the PTO engagement state. By monitoring whether the PTO is engaged or disengaged, the transmission control unit adapts the maximum allowable engine speed accordingly. This parameter change allows the vehicle to operate in two distinct modes: protected mode when PTO is engaged, and unrestricted mode when disengaged, optimizing both reliability and productivity across different operating conditions.
3Ease of operation
If the transmission control routine processes gear shifts without considering PTO speed limits, then ease of operation is improved, but harmful factors increase due to potential PTO damage from excessive engine speeds
Solution Approach 1:
The transmission control unit acts as an intermediary between the driver's gear shift requests and the actual transmission execution. It automatically evaluates each requested gear shift against the PTO speed limit and either permits or blocks the shift accordingly. This intermediary function protects the PTO from over-speeding damage without requiring the driver to manually monitor PTO speeds or make special adjustments, maintaining ease of operation while eliminating harmful effects.
Data Source
AI summary
Method for adapting an automated transmission of a heavy vehicle in consideration of a speed sensitive PTO. The method selects appropriate gears based on the constraint that the engaged PTO should remain below a set speed limit. The information about the speed limit of the PTO is used by the transmission control unit to ensure that the engine does not drive the PTO at a speed higher than the given speed limit. The engine speed may also be limited to reduce the engine speed to prevent it from exceeding the allowable PTO speed.