Torque Split Dual-Clutch Transmission for Launch NVH
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional dual-clutch transmissions face inefficiencies due to high heat generation in clutches during vehicle launch, leading to increased pumping losses, clutch overheating, and reduced durability, especially when using wet clutches, and result in torque jerks, noise, vibration, and harshness when using dry clutches.
Innovation Solution
A torque split dual-clutch transmission assembly that contemporaneously engages two clutches during vehicle launch to split engine torque between them, reducing heat generation and allowing for more efficient cooling, increased durability, and improved performance by distributing torque through multiple gearsets and intermediate shafts, enabling the use of dry clutches without overheating and allowing for exclusive first gear launches for better acceleration and reduced NVH.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single clutch is used to transmit all engine torque during vehicle launch, then the clutch can provide sufficient torque capacity, but the clutch generates excessive heat leading to overheating and reduced durability
Solution Approach 1:
The patent divides the single clutch into two separate clutches (first clutch and second clutch), each capable of handling a portion of the engine torque. During vehicle launch, both clutches are engaged simultaneously to split the torque transmission duty, reducing heat generation in each individual clutch and improving overall durability.
2Temperature
If wet clutches are used with high volume fluid flow for cooling, then clutch temperature is controlled, but pump size increases and parasitic losses increase reducing transmission efficiency
Solution Approach 1:
By segmenting the torque transmission into two clutches, the heat generation per clutch is reduced by approximately half. This allows the use of smaller cooling systems or even air-cooling for dry clutches, significantly reducing pump size and parasitic pumping losses while maintaining effective clutch temperature control.
3Loss of energy
If dry clutches are used to reduce pumping losses, then transmission efficiency improves, but repeated launches cause clutch overheating
Solution Approach 1:
The patent enables the use of dry clutches by splitting the torque duty between two clutches. This segmentation reduces heat generation enough to allow air-cooling to be effective, maintaining transmission efficiency while preventing overheating during repeated launches.
4Object-affected harmful factors
If clutch slip is permitted during vehicle launch to reduce noise and vibration, then NVH performance improves, but extended slip time causes clutch overheating and structural damage
Solution Approach 1:
By splitting the torque transmission between two clutches, the heat generation during slip is reduced by half. This allows for extended slip durations to achieve smooth launches and reduce NVH without causing overheating or structural damage to the clutch components.
5Adaptability or versatility
If additional gear ratios are added by increasing the number of gears on layshafts, then the transmission provides more gear ratios, but the transmission becomes larger, heavier, and more complex
Solution Approach 1:
The patent makes the existing gears on each layshaft multi-functional by enabling them to operate in two different torque paths. The first layshaft with odd-numbered gears and the second layshaft with even-numbered gears can both handle first gear launches when both clutches are engaged, effectively providing multiple gear ratio options without adding physical gears.
6Temperature
If alternating first gear and second gear launches are used to allow clutch cooling, then clutch overheating is prevented, but torque jerks and acceleration performance deteriorate
Solution Approach 1:
The patent eliminates the need for alternating gear launches by segmenting the torque transmission into two clutches. Both clutches can remain engaged simultaneously during first gear launches, providing continuous cooling capability while maintaining consistent acceleration performance and eliminating torque jerks associated with gear alternation.
Data Source
AI summary
A torque split dual-clutch transmission assembly is disclosed that splits the torque generated by an engine between at least two sets of transfer gears that are selectively coupled to first and second layshafts or intermediate shafts. A first input hub is connected to the first layshaft by a first clutch and a second input hub is connected to the second layshaft by a second clutch. A first gearset is carried on the first layshaft and a second gearset is carried on the second layshaft. Each set of transfer gears receives torque from either the transmission input shaft or the first and second layshafts in response to contemporaneous engagement of the first clutch and the second clutch, which can be used during vehicle launch to split the torque applied to the first and second clutches.