Warming Traction Battery via Engine Rotation
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Solution Overview
Problem
The performance of lithium-ion traction batteries in electrified vehicles is limited in cold environments, necessitating a method to effectively warm up the batteries for improved power delivery.
Innovation Solution
A system and method where a controller, responsive to the vehicle's stationary state, battery temperature below a threshold, and sufficient state-of-charge, uses the electric machine to rotate the engine without fuel supply, thereby warming the traction battery through discharge and charging processes, including strategies for torque management and fuel shutoff/reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the traction battery operates in cold environments, then the vehicle can be used in winter conditions, but the battery power performance is limited
Solution Approach 1:
The system performs preliminary warming of the traction battery before cold-weather operation by using the engine-driven heater to raise battery temperature to an optimal range, thereby preventing power performance degradation during actual cold-weather driving
Solution Approach 2:
The system changes the temperature parameter of the traction battery from cold conditions to optimal operating temperature through controlled heating, thereby improving battery power performance while maintaining cold environment adaptability
2Temperature
If the engine is rotated by the electric machine without fuel supply to warm the battery, then the battery temperature increases, but energy is consumed from the battery
Solution Approach 1:
The system uses periodic alternation between engine-driven heating mode and battery-powered electric machine mode, switching between fuel supply and no fuel supply conditions to warm the battery while managing energy consumption cycles
Solution Approach 2:
The system converts the potentially harmful effect of battery energy depletion into a beneficial warming process by using controlled discharge to drive the electric machine, which generates heat through mechanical friction and electrical resistance in the engine components
3Productivity
If the controller manages torque and fuel supply to optimize battery warming, then warming efficiency improves, but system complexity increases
Solution Approach 1:
The controller continuously monitors battery temperature, state of charge, and engine parameters, using feedback loops to dynamically adjust torque management and fuel supply strategies, thereby optimizing warming efficiency while maintaining manageable control complexity through established control algorithms
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
Enhances battery performance in cold conditions by effectively warming the traction battery, ensuring reliable power delivery and improved vehicle operation.
Implementation Method 1
an electric machine coupled to the engine
Implementation Method 2
rotating the engine via the electric machine powered by the traction battery while no fuel is supplied to the engine
Data Source
AI summary
A vehicle includes an engine, an electric machine, a traction battery, and a controller. The controller, responsive to the vehicle not moving, a temperature of the traction battery being less than a temperature threshold, and a state-of-charge of the traction battery being greater than a state-of-charge threshold, rotates the engine via the electric machine powered by the traction battery while no fuel is supplied to the engine.