Hybrid Drivetrain Engine Start During Load Shift
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Solution Overview
Problem
In parallel hybrid vehicles, starting the internal combustion engine during a shift under load is often disruptive and uncomfortable, leading to increased disturbances in the drivetrain and reduced comfort levels.
Innovation Solution
The method involves starting the internal combustion engine during a shift under load by using the electric machine, where the clutch between the engine and the electric machine is engaged, and the electric machine's speed is adapted to synchronize with the new gear, utilizing the electric machine's mass moment of inertia as starting torque, and transitioning to torque-regulated mode once synchronized, allowing for smooth engine startup.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the internal combustion engine is started during a shift under load, then the engine can be restarted quickly to meet power demands, but drivetrain disturbances increase and comfort decreases
Solution Approach 1:
The patent applies preliminary action by pre-engaging the clutch before the shift is completed and pre-synchronizing the engine speed to the target speed of the new gear. This preparation eliminates the need for speed adaptation during the shift, thereby reducing drivetrain disturbances while enabling quick engine restart.
Solution Approach 2:
The patent dynamically adjusts the engine speed during the shift process to match the target speed of the new gear. By continuously adapting the engine speed in real-time, the system minimizes speed differences and reduces drivetrain disturbances during the transition.
2Power
If the engine is started during a shift under load, then power availability is maintained, but shifting comfort is reduced
Solution Approach 1:
The clutch is engaged in advance before the shift completes, and the engine speed is pre-synchronized to the target speed. This preliminary preparation allows the shift to proceed smoothly without disruptions to power delivery, maintaining power availability while improving shifting comfort.
Solution Approach 2:
The engine speed parameter is dynamically changed during the shift to match the target speed of the new gear. This parameter adjustment ensures smooth torque transition and maintains power availability while enhancing shifting comfort.
3Device complexity
If traditional engine starting methods are used during shift, then the procedure is simple, but the shift sequence becomes complex and disturbances increase
Solution Approach 1:
The patent merges the engine starting process with the shift operation by engaging the clutch and synchronizing engine speed during the shift sequence. This integration eliminates the need for separate starting procedures, simplifying the overall process while improving shift efficiency and reducing disturbances.
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 approach reduces drivetrain disturbances, enhances shifting comfort by precise and dynamic speed regulation of the electric machine, and simplifies the shift sequence, ensuring smooth torque transition from the electric machine to the internal combustion engine.
Implementation Method 1
utilizing the electric machine's mass moment of inertia as starting torque
Data Source
AI summary
A method for starting the internal combustion engine, in parallel hybrid vehicles, in which the internal combustion engine is started, during a shift under load in purely electric driving operation, by the electric machine.