Hybrid Engine Start Preloaded Damper Spring
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Solution Overview
Problem
During engine restarts in hybrid electric vehicles, the torsion damper may bottom out or oscillate due to high torque, potentially damaging the flywheel and affecting engine restart consistency.
Innovation Solution
Preloading the torsion damper spring with torque from an electric motor through a clutch before engine cranking, increasing clutch torque capacity and reducing engine oscillation by storing potential energy in the damper spring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high torque is transmitted through the torsion damper during engine cranking, then the engine can be started, but the damper may bottom out or oscillate causing damage or inconsistency
Solution Approach 1:
The torsion damper spring is preloaded with a predetermined magnitude before engine cranking begins. This preliminary action prepares the damper to absorb the high cranking torque without bottoming out or oscillating, ensuring consistent and reliable engine restarts while allowing the necessary power transmission
2Productivity
If the torsion damper spring is preloaded before engine cranking, then engine oscillation is reduced and start time is shortened, but additional control complexity is introduced
Solution Approach 1:
The spring preload is applied in advance during a coasting period before the engine cranking command is executed. This preliminary action eliminates the need for spring displacement during the critical start phase, reducing engine oscillation and shortening the overall start time while the control sequence manages the added complexity
3Power
If the clutch torque capacity is increased to transmit cranking torque, then the engine can be cranked effectively, but the clutch may slip or wear under excessive torque
Solution Approach 1:
The spring preload is applied before the high torque cranking phase, during a period when the clutch is engaged but before maximum torque demand occurs. This timing allows the clutch to transmit the preload torque without experiencing the extreme stresses of full cranking torque, reducing slip and wear while maintaining effective power transmission
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 method reduces engine oscillation and variability during starts, shortening the engine start process by eliminating the need for spring displacement after the engine start command, and preventing damper bottoming out.
Implementation Method 1
preloading a spring of a torsion damper by transmitting torque having a magnitude less than engine cranking torque from an electric motor through a clutch to the spring, before cranking the engine
Data Source
AI summary
A method for starting an engine includes preloading a spring of a torsion damper by transmitting torque having a magnitude less than engine cranking torque from an electric motor through a clutch to the spring, before cranking the engine, increasing a torque capacity of the clutch, and using the electric motor to crank the engine in response to a command to start the engine.