Hybrid Drive Gearshift Using Series-Parallel Torque Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing hybrid vehicle drive systems face issues with gear changes leading to loss of traction and impaired driving comfort due to high loads on drive elements.
Innovation Solution
A method for operating a hybrid vehicle drive unit that ensures gear changes are performed without affecting traction by maintaining consistent drive torque and power through a combination of internal combustion engine, first and second electric motors, and a transmission, allowing for smooth transitions between parallel and series hybrid modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If gear changes are performed in conventional hybrid vehicle drive systems, then the transmission ratio is changed to adapt to different driving conditions, but loss of traction and impaired driving comfort occur due to high loads on drive elements
Solution Approach 1:
The first electric machine acts as an intermediary between the internal combustion engine and the second electric machine during gear changes. It generates compensating torque to offset the torque drop that occurs when the transmission ratio changes, thereby maintaining stable drive torque at the drive wheels and preventing loss of traction
Solution Approach 2:
The control device prepares for the gear change by adjusting the torque output of the first electric machine in advance. Before the gear change is executed, the first electric machine increases its torque generation to compensate for the upcoming torque drop, ensuring smooth transition without affecting driving comfort or traction
2Adaptability or versatility
If gear changes are performed in conventional hybrid vehicle drive systems, then the transmission adapts to different driving conditions, but high loads are imposed on drive elements causing impaired driving comfort
Solution Approach 1:
The first electric machine serves as a mediator that absorbs and compensates for the torque fluctuations during gear changes. By generating additional torque during the transition, it smooths out the load variations that would otherwise be transmitted to the drive wheels, maintaining driving comfort while still adapting to different driving conditions
Solution Approach 2:
The system dynamically changes the torque parameters of the first electric machine during gear transitions. The control device adjusts the torque output of the first electric machine based on the gear change state, increasing torque generation during the transition period and then reducing it after the gear change is complete, thereby smoothing the overall torque delivery
3Reliability
If the internal combustion engine operates at increased power output to maintain drive torque during gear changes, then drive torque consistency is maintained, but fuel consumption increases
Solution Approach 1:
The first electric machine acts as an intermediary that provides the additional torque needed during gear changes without requiring the internal combustion engine to increase its power output. The electric machine generates the compensating torque while the internal combustion engine maintains its original torque output, thereby maintaining drive torque consistency while avoiding increased fuel consumption
Solution Approach 2:
The system replaces the mechanical solution of increasing internal combustion engine power with an electrical solution. Instead of mechanically increasing the engine's torque output (which would require more fuel), the system uses the first electric machine to generate the additional torque electrically, substituting a mechanical energy conversion process with an electrical one that is more efficient
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 reliable and comfortable gear changes by maintaining drive torque and power consistency, optimizing fuel efficiency, and reducing load on drive elements.
Implementation Method 1
a first electric machine (9), which can be coupled to an output shaft (31) of the internal combustion engine (5), or to a drive shaft of a drive wheel (15)... a second electric machine (11), which can be coupled to a drive shaft of a drive wheel (15)... generate electrical energy... generate the drive torque
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A method for operating a drive device (3) of a hybrid vehicle (1) is made available, wherein the method comprises: operating, while a first gear speed of the transmission (19) is engaged, the internal combustion engine (5) at a first rotational speed (637, 413) for the first gear speed in a parallel hybrid operating mode in which, when the main clutch (K0) is closed, a traction drive torque acting on the drive wheel (15) is generated by means of the internal combustion engine (5); changing into a serial hybrid operating mode in which the internal combustion engine (5) drives the first electric machine (9) to generate electrical energy which is used by the second electric machine (11) to bring about the traction drive torque; opening the main clutch (K0); setting a rotational speed of the internal combustion engine (5) to a second rotational speed (639, 415) for a second gear speed of the transmission (19) in the parallel hybrid operating mode when the main clutch is opened; engaging the second gear speed of the transmission (19); closing the main clutch (K0); and changing into the parallel hybrid operating mode while the second gear speed is engaged.