Hybrid Transmission Positive-Locking Shift Elements
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Solution Overview
Problem
Current hybrid vehicle transmissions suffer from frictional losses and complex electrohydraulic control due to the use of power-shift automatic transmissions with independent electric machines that do not enhance the transmission's functionality.
Innovation Solution
Integration of two electric machines within the transmission itself, utilizing positive-locking shifting elements and synchronizing them to engage gears without complex mechanical synchronization devices, allowing exclusive activation by the electrical machines for gear shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If power-shift automatic transmissions with frictional shifting elements are used, then gear shifting is enabled, but frictional losses and complex electrohydraulic control arise
Solution Approach 1:
The patent replaces frictional shifting elements with positive-locking shifting elements that engage gear changes through direct mechanical locking rather than friction-based clutch engagement. This substitution eliminates the frictional losses inherent in traditional power-shift automatic transmissions while maintaining gear shifting capability.
Solution Approach 2:
The invention extracts and removes the frictional clutch components from the transmission system, replacing them with a positive-locking mechanism. By taking out the friction-based shifting elements, the system eliminates the associated energy losses and simplifies the control system.
2Ease of operation
If frictional shifting elements are used in automatic transmissions, then gear engagement is achieved, but complex electrohydraulic control is required
Solution Approach 1:
The patent replaces the complex electrohydraulic control system with a simpler electrical control system that directly actuates the positive-locking shifting elements. This substitution eliminates the need for hydraulic pumps, valves, and fluid pressure management, significantly reducing system complexity.
Solution Approach 2:
The invention extracts and removes the electrohydraulic control components from the transmission system. By eliminating the hydraulic control circuitry and replacing it with direct electrical actuation of the positive-locking elements, the system achieves gear engagement with much simpler control architecture.
3Adaptability or versatility
If electric machines are placed outside the transmission (P2 hybrid), then hybrid functionality is achieved, but the transmission operates independently without benefits
Solution Approach 1:
The patent merges the electric machines with the transmission system by integrating them directly into the planetary gear set architecture. The electric machines are coupled to specific transmission elements (sun gears, ring gears, or planet carriers) to form a unified power transmission system that enables multiple operating modes including electric-only drive, engine-only drive, and combined power mode.
Solution Approach 2:
The invention makes the transmission system universal by enabling it to perform multiple functions: traditional mechanical gear shifting, electric motor drive, generator mode, and combined power delivery. The integrated design allows the same transmission elements to serve both mechanical and electrical functions, eliminating the need for independent operation.
4Ease of operation
If complex mechanical synchronization devices are used, then gear engagement is achieved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical synchronization devices with an electrical synchronization system. Instead of using mechanical synchronizers that rely on friction rings and conical surfaces, the invention uses electrical machines to actively control and synchronize the rotational speeds of transmission elements before engagement, eliminating the need for complex mechanical synchronization hardware.
Solution Approach 2:
The invention substitutes electrical control mechanisms for mechanical synchronization devices. By using the electrical machines to actively match rotational speeds through electrical torque application, the system achieves gear engagement without requiring complex mechanical synchronizer assemblies.
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
This approach reduces frictional losses and simplifies control, enabling a more efficient and effective gear shifting mechanism with reduced complexity, supporting a wide range of gears including nine forward and one reverse, while allowing for purely electrical reverse gear operation.
Implementation Method 1
Each of the two electrical machines has a rotor and a stator. Each of the two electrical machines is provided for driving at least one transmission element of the automatic hybrid transmission.
Implementation Method 2
The automatic hybrid transmission has only positive-locking shifting elements. By closing a shifting element, the two transmission elements associated with the shifting element can be coupled, in particular rotationally coupled.
Data Source
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AI summary
Method for shifting an automatic hybrid transmission without interruption caused by tensile forces, said hybrid transmission comprising two electrical machines (EMA, EMB) and exclusively form-fit shift elements (SE1-SE10) as its shift elements, wherein by closing each of the shift elements (SE1-SE10) in each case one transmission element can be coupled to another transmission element. At least one of the form-fit shift elements (SE1-SE10) is closed to engage a target gear. The transmission elements allocated to the at least one shift element (SE1-SE10) to be closed are synchronised prior to closure by corresponding control of at least one of the two electrical machines (EMA, EMB).