Hybrid Drive Mode Switching for Continuous Tractive Torque
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Solution Overview
Problem
Existing hybrid vehicle drive systems often experience interruptions in tractive power during transitions between different drive units, compromising driving comfort and reliability.
Innovation Solution
A method for operating a hybrid vehicle drive device that includes an internal combustion engine, a first electric machine, a second electric machine, and an electric accumulator, allowing for seamless transitions between three operating modes: purely electrical, series hybrid, and parallel hybrid operations, by controlling the traction drive torque to maintain continuity and optimize energy usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If transitions between different drive units are implemented in hybrid vehicle drive systems, then versatility and adaptability of the drive system is improved, but interruptions in tractive power occur during transitions, compromising driving comfort and reliability
Solution Approach 1:
The patent applies the principle of continuity of useful action by ensuring that during transitions between different drive unit operating modes (purely electric, series hybrid, parallel hybrid), the tractive power delivered to the drive wheels remains continuous without interruptions. This is achieved through coordinated control of the purely electric drive unit and the hybrid drive unit, where torque from both units is blended smoothly during mode transitions, preventing any gap in tractive power delivery and thus maintaining driving comfort and reliability while allowing versatile operating mode changes
2Use of energy by moving object
If multiple drive units are used in hybrid vehicle systems, then energy efficiency can be optimized under different conditions, but the complexity of controlling transitions between units increases
Solution Approach 1:
The patent applies the principle of dynamics by implementing a dynamic control system that automatically selects and transitions between different drive unit operating modes based on real-time vehicle conditions such as driver demand, vehicle speed, and battery state of charge. The control system dynamically adjusts the contribution of the purely electric drive unit and hybrid drive unit, enabling optimal energy efficiency across varying operating conditions while managing control complexity through adaptive algorithms that respond to changing conditions rather than requiring complex pre-programmed transition logic
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
Ensures reliable and comfortable transitions between drive units without noticeable changes in speed or acceleration, improving energy efficiency and reducing energy consumption by optimizing the operating modes based on vehicle conditions.
Implementation Method 1
the first electric machine, in the motor or generator mode, engages the speed change device in a controlling manner
Implementation Method 2
a drive torque acting on the drive wheel is generated by means of the second electric machine
Implementation Method 3
a planetary gear with a speed change device. The planetary gear has an input and an output side
Data Source
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AI summary
A method is provided for operating a drive unit (3, 203) of a hybrid vehicle (1, 201) for driving a drive wheel (15, 215), wherein the drive unit comprises an internal combustion engine (5, 205), a first electric machine (9, 209) coupled to the internal combustion engine, a second electric machine (11, 211), an electric accumulator (13, 213) and a main coupling (17, K0) between the internal combustion engine (5, 205) and the drive wheel (15, 215), wherein the method includes: operating the drive unit (3, 203) in a first operating mode of the following three operating modes: a purely electric operation, a series hybrid operation, a parallel hybrid operation;and at least once switching from the first operating mode to a second operating mode of the three operating modes, wherein the drive torque provided during the switch from the first operating mode to the second operating mode corresponds to a suitably selectable curve between the drive torque provided before and after the switch; wherein, if the first operating mode is the purely electric operation and the second operating mode is the series hybrid operation, the switch comprises: up to a first time (t1) operating the second electric machine (11, 211) in electromechanical operation with electrical energy from the accumulator (13, 213);From the first time point (t1) and at least until a second time point (t2), from which the rotational speed of the internal combustion engine (5, 205) reaches or exceeds a starting speed threshold (113), the first electric machine (9, 209) is operated in electric motor mode to generate torque in order to increase the rotational speed of the internal combustion engine (5, 205); from the second time point (12), fuel is supplied to the internal combustion engine (5, 205); from a third time point (t3), at which the rotational speed of the internal combustion engine (5, 205) reaches or exceeds a target speed for series operation, the first electric machine (9, 209) is operated in generator mode to generate electrical energy;Between the third time point (t3) and a fourth time point (t4), the second electric machine (11, 211) is operated in electromotive mode by means of a decreasing supply of electrical energy from the accumulator (13, 213) and an increasing supply of electrical energy generated by the internal combustion engine (5, 205) via the first electric machine (9, 209); and from the fourth time point (t4), the second electric machine (11, 211) is operated in electromotive mode with electrical energy generated by the internal combustion engine (5, 205) via the first electric machine (9, 209).