Dog Clutch Transmission Control for Torque Capacity Detection
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Solution Overview
Problem
In vehicle transmissions with dog clutches, determining the torque capacity and detecting gear degradation is challenging due to the lack of slip between the dog clutch and gear, making it difficult to assess whether the gear can meet commanded torque requirements.
Innovation Solution
A method and system that estimate the maximum engagement depth of the dog clutch, allowing for the determination of torque capacity by measuring the tooth overlap, and a controller executes instructions to indicate gear degradation if the commanded torque exceeds the torque capacity, enabling the transmission to shift gears accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a dog clutch is used to engage and disengage gears, then efficient torque transfer and lower heating are achieved, but it becomes difficult to determine the amount of torque transferred and detect gear degradation
Solution Approach 1:
The patent introduces an intermediary measurement approach by using a friction clutch in conjunction with the dog clutch. The friction clutch serves as a mediator that can slip and generate measurable thermal effects, allowing indirect measurement of torque transfer while the dog clutch maintains efficient power transmission. This resolves the contradiction by adding a measurement capability without compromising the primary function of the dog clutch.
2Reliability
If the dog clutch and gear rotate at equal speeds when engaged, then efficient torque transfer is achieved, but it becomes difficult to determine whether the gear is degraded
Solution Approach 1:
The friction clutch acts as an intermediary device that enables gear degradation detection. By allowing controlled slippage and generating measurable thermal effects, the friction clutch provides a means to assess gear condition without interfering with the synchronous rotation and efficient torque transfer of the dog clutch-gear engagement.
3Power
If no slip occurs between the dog clutch teeth and gear teeth, then efficient torque transfer is achieved, but torque capacity measurement becomes difficult
Solution Approach 1:
The friction clutch serves as an intermediary that enables torque capacity measurement through its slippage characteristics. While the dog clutch maintains slip-free efficient torque transfer, the friction clutch's controlled slippage generates thermal effects that can be measured to determine torque capacity, thus resolving the measurement difficulty without compromising power transfer efficiency.
Data Source
AI summary
Methods and systems for operating a transmission that includes one or more dog clutches are described. In one example, a torque capacity of a gear is estimated from an engagement depth of the dog clutch, and the gear may be held or shifted according to the torque capacity of the gear and a commanded torque.