HVAC Power Allocation for Low Battery Vehicles
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Solution Overview
Problem
Existing HVAC systems in vehicles experience inefficient power allocation when battery power is low, leading to either insufficient power for critical defogging/defrosting operations under harsh conditions or excessive power consumption under ideal conditions, due to linear power reduction methods.
Innovation Solution
A non-linear power reduction method is implemented, where the HVAC power consumption value remains constant until battery power drops below a first low value, then decreases at a varying non-linear rate, and further decreases linearly when power is below a second low value, ensuring adequate power for defogging/defrosting while optimizing power distribution among vehicle devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If linear power reduction method is used for HVAC unit, then power allocation is simplified, but power may be insufficient for critical defogging/defrosting operations under harsh conditions
Solution Approach 1:
The patent implements dynamic power allocation by transitioning from a static linear reduction method to a dynamic non-linear reduction method. The system continuously monitors battery state of charge and adjusts HVAC power consumption accordingly, using different reduction rates (first non-linear rate, second non-linear rate, and linear rate) based on current battery power levels, thereby optimizing both reliability and efficiency
Solution Approach 2:
The patent changes the power consumption parameter of the HVAC unit based on battery state of charge. By implementing non-linear power reduction curves with varying rates instead of a fixed linear reduction, the system adapts power allocation to match actual battery conditions, ensuring sufficient power for critical operations while preventing excessive consumption
2Device complexity
If linear power reduction method is used for HVAC unit, then power allocation is straightforward, but power consumption may be excessive under ideal climate conditions
Solution Approach 1:
The patent applies partial action by reducing HVAC power consumption only to the extent necessary based on actual battery state of charge and climate conditions. Instead of uniformly reducing power, the system implements selective power reduction using non-linear curves that maintain adequate power for essential HVAC functions while eliminating excessive consumption, thereby optimizing energy efficiency without compromising necessary operations
3Loss of energy
If power consumption value is suddenly decreased for HVAC unit, then battery power is preserved, but defogging/defrosting operations are hindered
Solution Approach 1:
The patent implements beforehand cushioning by using non-linear power reduction curves that gradually reduce HVAC power consumption as battery state of charge decreases, rather than applying sudden linear reductions. This cushioning approach ensures that critical defogging and defrosting operations maintain sufficient power until absolutely necessary, preventing abrupt disruptions to safety-critical functions while still preserving battery power for essential operations
Data Source
AI summary
A method and a system for changing the power consumption value available for an HVAC unit of a vehicle when an available battery power for batteries of the vehicle is low. A method and a system for non-linearly changing the power consumption value available for the HVAC unit when the available battery power decreases to a power value less than a low power value. The system can be a vehicle including batteries, an HVAC unit, an ECU and a memory. The method may include setting an HVAC power consumption value to a relatively constant power value when the available battery power is greater than a low power value and decreasing the HVAC power consumption value by a non-linear rate of power reduction when the available battery power decreases to a power value less than the low power value.