Hybrid Drive Train Planetary Gear Layout for Engine Starting
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Solution Overview
Problem
Existing hybrid drive trains face challenges in efficiently starting the internal combustion engine using the electric machine across all driving situations, particularly regarding vehicle speed and cost optimization.
Innovation Solution
A drive train configuration with two planetary gear sets, where the first planetary gear set can engage multiple gear stages based on driving parameters, and the selected gear remains engaged to start the internal combustion engine, allowing drive power transfer from the electric machine via the transmission to the internal combustion engine, utilizing a specific gear level determined by parameters like performance demand, vehicle speed, battery charge, road inclination, or traffic light status.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the electric motor is coupled to the output via a summing gear, then the speeds of both drive motors can be adjusted independently, but the device complexity increases due to additional planetary gear sets
Solution Approach 1:
The first planetary gear set is designed to serve multiple functions: it provides gear ratio changes during normal operation and simultaneously enables engine starting by the electric motor. The gear set can engage different gear stages (first, second, third gear ratios) depending on driving parameters, and the same structure facilitates power flow from electric motor to internal combustion engine for starting purposes.
2Adaptability or versatility
If multiple planetary gear sets are used to enable engine starting, then all driving situations can be covered, but the size and cost of the drive train increase
Solution Approach 1:
The first planetary gear set is designed to serve multiple functions: it provides gear ratio changes during normal operation and simultaneously enables engine starting by the electric motor. The gear set can engage different gear stages (first, second, third gear ratios) depending on driving parameters, and the same structure facilitates power flow from electric motor to internal combustion engine for starting purposes.
Solution Approach 2:
The patent combines the engine starting function with the existing gear ratio change mechanism. Instead of adding a separate starting mechanism, the electric motor is integrated into the summing gear configuration, and the first planetary gear set is used for both gear ratio adjustment and enabling the starting process by controlling clutch engagement and power flow direction.
3Productivity
If a specific gear ratio is engaged for engine starting, then the starting process can be optimized, but the device complexity increases due to additional switching elements
Solution Approach 1:
The patent employs dynamic control of clutch engagement and gear ratio selection based on real-time driving parameters. The control unit monitors vehicle speed, power demand, battery charge level, road gradient, and traffic light status to dynamically select the appropriate gear ratio (first, second, or third gear) for engine starting. This dynamic adaptation allows optimization of the starting process for different driving situations without requiring a fixed, overly complex mechanical structure.
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
Enables seamless starting of the internal combustion engine by the electric machine in all driving conditions, optimizing gear usage and reducing size and cost, while maintaining efficient power transmission through the engaged gear stages.
Implementation Method 1
a transmission arrangement (5) having a first planetary gear set (P1) and a second planetary gear set (P2)
Data Source
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AI summary
A drive train (1), in particular for a motor vehicle, is proposed comprising an internal combustion engine (3), a first switching arrangement (51), a transmission arrangement (5), an output (4) operatively or rotationally connected to the transmission arrangement, and a second switching arrangement (52), wherein these components are arranged along a main axis (Z) and the transmission arrangement (5) has a first and a second planetary gear set (P1, P2), wherein the sun gear (11) of the first planetary gear set (P1) can be connected to the internal combustion engine (3) by means of a clutch (A), wherein the second planetary gear set (P2) is designed as a summing gear and is coupled to the first planetary gear set (P1), to an electric motor (2), and to the output (4), wherein the sun gear (11) of the first planetary gear set (P1) can further be connected to a housing by means of a brake element (E), wherein the clutch (A) and the brake element (E),also on the main axis (Z) and on opposite sides of the gear assembly (5), and the sun gear (11) is rotatably mounted to a sun gear (21) of the second planetary gear set (P2), and the planet carrier (12) of the first planetary gear set (P1) is coupled to the second planetary gear set (P2), and wherein a ring gear (13) of the first planetary gear set (P1) can be connected to the internal combustion engine (3) by means of a further coupling (B).