Hybrid Vehicle Launch Control Torque Management
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Solution Overview
Problem
Hybrid vehicles face challenges in smooth acceleration from standstill, as the internal combustion engine often needs to be tow-started, leading to jerking when transitioning from electric motor acceleration, and lack a 'launch control' mode like sports cars, which prioritizes rapid acceleration.
Innovation Solution
A method allowing selective acceleration modes: one where the electric motor initially accelerates with partial torque to tow-start the internal combustion engine, and another where the engine is on from the beginning for rapid acceleration, enabling smooth transition and preventing jerking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the electric motor uses full available torque for acceleration, then acceleration performance is improved, but the internal combustion engine cannot be tow-started smoothly causing jerking
Solution Approach 1:
The electric motor applies partial torque (not full available torque) during the initial acceleration phase to reserve sufficient torque for smooth tow-starting of the internal combustion engine. This partial action allows the engine to be started without causing jerking, while still achieving acceptable acceleration performance.
Solution Approach 2:
The electric motor performs preliminary acceleration with controlled torque before the internal combustion engine takes over. This preliminary action ensures the vehicle is already moving when the engine starts, facilitating smoother transition and eliminating jerking during the torque transfer phase.
2Use of energy by moving object
If the internal combustion engine is tow-started during acceleration, then fuel consumption is reduced, but jerking occurs during torque transition
Solution Approach 1:
The electric motor deliberately uses only partial torque during acceleration to maintain a torque reserve. This reserved torque is specifically allocated for smooth tow-starting of the internal combustion engine, preventing jerking while enabling fuel-efficient operation by keeping the engine running.
Solution Approach 2:
The electric motor acts as an intermediary during the transition phase, providing the necessary torque to start the internal combustion engine without causing abrupt changes in vehicle acceleration. This mediator role ensures smooth handover from electric-only mode to hybrid mode.
3Ease of manufacture
If a separate electric motor is used for tow-starting, then engine starting is simplified, but device complexity increases
Solution Approach 1:
The electric motor is designed to perform multiple functions: primary propulsion, acceleration assistance, and tow-starting of the internal combustion engine. This multi-functionality eliminates the need for a separate tow-start motor, reducing device complexity while maintaining ease of engine starting.
Solution Approach 2:
The tow-starting function is merged with the primary electric motor rather than being implemented as a separate system. This consolidation combines propulsion and engine-starting capabilities into a single motor unit, simplifying the overall vehicle architecture.
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
The method provides comfortable and fuel-saving acceleration in one mode and rapid acceleration in another, enhancing riding comfort and safety while managing fuel consumption.
Implementation Method 1
the electric motor initially accelerates the vehicle with a partial torque of an available torque
Implementation Method 2
the internal combustion engine subsequently takes over the acceleration of the vehicle or contributes to the acceleration
Data Source
AI summary
The functionality of a “Launch Control” is implemented in a hybrid vehicle, i.e. the hybrid vehicle can be accelerated to a maximum degree by starting the internal combustion engine immediately from the stationary state (S20), and acceleration takes place with the aid of the electric motor with full torque (S22) before a changeover to accelerating the internal combustion engine takes place (S24). The “Launch Control” differs from a further mode in which firstly acceleration takes place from the stationary state using a partial torque of the electric motor (S14), with the result that the internal combustion engine can be tow-started by means of the electric motor (S16) before a changeover to acceleration using the internal combustion engine (S18) occurs.