Motor Vehicle Thermal Management via Bidirectional Coolant Flow
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Solution Overview
Problem
Current thermal management systems for electrified motor vehicles are not operated efficiently, leading to reduced vehicle range during heating operations, as existing heat sources are not utilized optimally.
Innovation Solution
A method involving the circulation of coolant through specific series circuits, including a motor cooling circuit, chiller circuit, and high voltage store/chiller circuit, with time-shifted and dependent operating states to maximize heat utilization without additional components or valves, allowing for efficient thermal management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If coolant is circulated through the LT radiator in a motor cooling circuit to cool the electric motor, then the electric motor temperature is reduced, but the heating efficiency for the vehicle interior is decreased
Solution Approach 1:
The system dynamically switches the flow direction of coolant through the LT radiator between first direction (motor cooling mode) and second direction (heating mode) based on operational requirements. The motor circuit pump can be activated or deactivated, and the chiller section pump is activated only when needed, creating a dynamic thermal management system that adapts to different operating conditions to optimize both motor cooling and interior heating efficiency
Solution Approach 2:
The system implements time-shifted operating states where the motor cooling circuit and chiller cooling circuit are activated at different times. The motor cooling circuit operates in the first operating state, and the chiller cooling circuit operates in the second operating state with the coolant flowing in the opposite direction through the LT radiator. This periodic switching allows the system to alternate between motor cooling and interior heating modes, maximizing the utilization of waste heat from the motor while maintaining effective thermal management
2Adaptability or versatility
If additional components or valves are added to enable bidirectional coolant flow through the LT radiator, then flow direction control is improved, but device complexity increases
Solution Approach 1:
Instead of adding complex valves to control flow direction, the system inverts the approach by using two separate pumps (motor circuit pump and chiller section pump) that can be independently activated. The flow direction through the LT radiator is controlled by which pump is active and the circuit configuration, eliminating the need for additional flow control valves while achieving bidirectional flow capability
Solution Approach 2:
The system uses the existing pump components (motor circuit pump and chiller section pump) to serve dual purposes: the motor circuit pump handles motor cooling flow, and the chiller section pump handles chiller cooling flow with reversed direction through the LT radiator. The existing pump infrastructure is leveraged to provide flow direction control without requiring additional dedicated flow control components
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 enhances the efficiency of thermal management systems by effectively utilizing waste heat from electric motors and energy stores, minimizing switching frequency, and maintaining temperature within defined limits, thereby improving vehicle range and comfort.
Implementation Method 1
circulating of coolant, at least in a first operating state, in a motor cooling circuit through a series circuit comprising a motor circuit pump, an electric motor and a low temperature (LT) radiator
Implementation Method 2
thermal management systems for electrified motor vehicles are known, which thermal management systems provide a heating capacity for a vehicle interior compartment by means of a heat pump functionality
Data Source
AI summary
A method for thermal management of a motor vehicle includes circulating of coolant, in a first operating state, at least in a motor cooling circuit through a series circuit that includes a motor circuit pump, an electric motor, and a low temperature (LT) radiator where the motor circuit pump is activated and where the coolant flows in a first direction through the LT radiator. The method further includes, time-shifted with respect to the first operating state, circulating of coolant, in a second operating state, at least in a chiller cooling circuit through a series circuit including a chiller, a chiller section pump, the motor circuit pump, and the LT radiator where the chiller section pump is activated, where the motor circuit pump is deactivated, where the coolant flows in a second direction through the LT radiator, and where the second direction is opposed to the first direction.