Overdrive Unit Planetary Gear Integration for Fuel Efficiency
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Solution Overview
Problem
Current manual automotive transmissions face challenges in achieving higher gear ratios for fuel efficiency and reduced CO2 emissions without increasing driver effort and vehicle redesign, as adding more gears complicates gear shifting and requires substantial modifications.
Innovation Solution
An overdrive unit with a planetary gear set and differential mounted in a housing, connected to a transverse mounted front wheel drive vehicle gearbox, featuring a clutch unit for selective engagement, allowing for increased fuel efficiency and reduced CO2 emissions by enabling a single output shaft and optional disconnect mode to reduce drag losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If more gears are added to manual automotive transmissions to achieve higher gear ratios for fuel efficiency, then fuel efficiency and reduced CO2 emissions are improved, but driver effort and gear shifting complexity increase
Solution Approach 1:
The transmission system is segmented into a manual gearbox and a separate overdrive unit. The overdrive unit contains a planetary gear set with multiple gear ratios that can be engaged independently of the main gearbox, providing additional high-speed gears without complicating the primary transmission operation.
Solution Approach 2:
A clutch unit acts as an intermediary between the manual gearbox and the overdrive unit. This clutch selectively engages or disengages the overdrive planetary gear set from the drivetrain, allowing the driver to access additional gear ratios only when needed for fuel-efficient cruising, without affecting normal manual gear shifting.
2Use of energy by moving object
If more gears are added to manual automotive transmissions to achieve higher gear ratios, then fuel efficiency is improved, but device complexity increases
Solution Approach 1:
The complex gear multiplication function is segmented into a separate overdrive unit with a planetary gear set. This modular approach isolates the complexity within a dedicated component that can be engaged only when high gear ratios are needed, keeping the main transmission simple and manageable.
Solution Approach 2:
The overdrive unit employs a dynamically engageable planetary gear set controlled by a clutch unit. The planetary gears can be selectively locked or unlocked to provide different gear ratios (including direct drive and overdrive ratios), allowing the system to adapt its complexity level based on driving conditions without permanently increasing mechanical complexity.
3Speed
If more gears are added to the transmission, then higher gear ratios are achieved, but overall length of the transmission increases
Solution Approach 1:
The overdrive unit with its planetary gear set is designed as a compact nested structure that integrates around the existing transmission output shaft. The planetary gears are arranged concentrically, with the sun gear, planetary gears, and ring gear nested within each other, minimizing the axial and radial space required while providing multiple gear ratios.
Solution Approach 2:
Instead of extending the transmission length axially to accommodate additional gears, the invention uses a planetary gear set that multiplies gear ratios in a radial and concentric arrangement. This dimensional change allows multiple gear ratios to be achieved within a compact footprint that does not significantly increase the overall transmission length.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves a 5-10% reduction in fuel consumption and allows for compact design, enabling seamless integration with existing packaging and reducing the need for extensive vehicle redesign, while allowing for automatic or manual clutch actuation.
Implementation Method 1
a planetary gear set (4) comprising a sun gear (4a), a planetary gear carrier (4b), one or more planetary gears (4c) and a ring gear (4d)
Implementation Method 2
a clutch unit (8) arranged to selectively connect the planetary gear set (4) with the drivetrain
Implementation Method 3
the planetary gear set is further operatively connectable to drive shafts of the vehicle via the differential
Data Source
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AI summary
The present invention relates to an overdrive unit (1) which is operatively connectable to a transverse mounted front wheel drive vehicle gearbox (2) which has been arranged to provide a single output shaft (3). A planetary gear set (4) and a differential (5) are mounted together in an overdrive unit housing (6) such that the output shaft (3) of the vehicle gearbox (2) is operatively connectable to the planetary gear set (4). The planetary gear set (4) is further operatively connectable to drive shafts (7a, 7b) of the vehicle via the differential (5). A clutch unit (8) is provided for selectively engaging gearing of the planetary gear set (4).