Automatic Transmission Return-to-Range Control Logic
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current automatic transmission systems require manual selection of gears after releasing the parking brake, which is time-consuming and inefficient, especially in vehicles that frequently stop and start, such as refuse packer vehicles.
Innovation Solution
An electrical control unit is implemented in the powertrain system that automatically returns the transmission to the previously selected forward or reverse gear when the service brake is applied and the parking brake is released, eliminating the need for manual gear selection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If manual gear selection is required after releasing the parking brake, then the transmission control system is simpler, but the driver workload increases and operational efficiency decreases
Solution Approach 1:
The transmission control unit automatically returns the transmission to the previously selected drive gear when the parking brake is released, without requiring manual intervention from the driver. The system serves itself by autonomously detecting the parking brake release condition and executing the gear transition based on stored gear history, thereby eliminating the need for manual gear selection and reducing driver workload.
Solution Approach 2:
The system stores the previously selected gear information in memory before the transmission shifts to neutral when the parking brake is applied. This preliminary storage of gear state information enables the automatic return-to-range function to restore the correct gear when the parking brake is released, eliminating the need for manual gear selection and improving operational efficiency.
2Loss of time
If automatic neutral shift function is implemented, then driver time is saved, but the system complexity and wiring requirements increase
Solution Approach 1:
The transmission control unit performs multiple functions: it monitors parking brake status, stores gear selection information, determines when to shift to neutral, and executes the automatic return-to-range function. By consolidating these functions into a single control unit that leverages existing sensors and processors, the system achieves automatic neutral shifting and return-to-range capabilities without proportionally increasing system complexity.
Solution Approach 2:
The patent combines the automatic neutral shifting function with the return-to-range function into a single integrated system. The same transmission control unit that manages neutral shifting also handles the automatic return to drive gear, and the gear history storage serves both functions. This merging of functions reduces overall system complexity compared to implementing separate systems for each function.
3Reliability
If redundant wiring is added for parking brake status detection, then reliability improves, but device complexity increases
Solution Approach 1:
The transmission control unit continuously monitors the parking brake sensor signal and uses this feedback to automatically control transmission gear transitions. The system reads the parking brake status, compares it with stored gear information, and automatically executes gear changes without requiring redundant wiring or manual intervention, thereby maintaining reliability while minimizing wiring complexity.
Data Source
AI summary
A powertrain incorporating an automatic transmission and an electrical control unit for control thereof, the electrical control unit implementing a return-to-range feature that will return to the automatic transmission to a previously selected forward (and, in some embodiments, reverse) gear when the service brake is applied first and then the parking brake is released while the service brake remains applied. Other embodiments are also disclosed.