Hybrid Vehicle Driving Device Engine Startup Torque Management
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Solution Overview
Problem
Hybrid vehicles face challenges in starting the engine efficiently when switching from electric vehicle mode to hybrid mode, as the required torque increases, making it difficult to start the engine appropriately.
Innovation Solution
A driving device for hybrid vehicles that includes a transmission unit capable of changing engine speed, a rotating electric machine to supply torque for engine startup, and a differential unit connected to the drive wheels, with the transmission unit switched to a high-speed gear shift stage during engine startup, allowing for a low-torque startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the rotating electric machine increases the rotating speed of the engine during startup, then the engine can be started up, but the torque necessary increases
Solution Approach 1:
The transmission unit dynamically changes its transmission ratio during engine startup by switching from a low-speed gear shift stage to a high-speed gear shift stage. This dynamic adjustment allows the system to optimize the balance between engine rotating speed and required torque, reducing the startup torque demand while maintaining effective engine cranking speed
Solution Approach 2:
The system changes the transmission parameter (transmission ratio) of the transmission unit during the engine startup process. By switching to a high-speed gear shift stage, the transmission ratio is adjusted to reduce the torque multiplication effect, thereby lowering the torque necessary from the rotating electric machine while still achieving the required engine rotating speed for successful startup
2Force
If the transmission unit is switched to a high speed gear shift stage during engine startup, then the torque necessary for startup decreases, but the control complexity increases
Solution Approach 1:
The control system performs preliminary action by pre-determining the optimal gear shift stage for engine startup based on vehicle operating conditions. The transmission unit is switched to the appropriate high-speed gear shift stage before engine startup is initiated, ensuring that the torque necessary for startup is minimized while avoiding complex real-time adjustments during the critical startup moment
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 configuration enables the engine to be started up with reduced torque, ensuring efficient startup and smooth transition from electric to hybrid power sources.
Implementation Method 1
a rotating electric machine, wherein the rotating electric machine is configured to supply a torque for increasing the rotating speed of the engine at the time of starting up of the engine to the engine through the transmission unit
Data Source
AI summary
A driving device for a hybrid vehicle includes a transmission unit configured to output a rotation of an engine while changing rotating speed of the engine; and a first rotating electric machine. The first rotating electric machine is configured to supply a torque for increasing the rotating speed of the engine at the time of starting up of the engine to the engine through the transmission unit. At the time of starting up of the engine, the gear shift stage of the transmission unit is switched to an overdrive state. Thus, a torque sufficient for starting up of the engine can be supplied to the engine, and hence the engine can be appropriately started up.