Vehicle HVAC Waste-Heat Simulation for Energy Consumption Testing
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Solution Overview
Problem
Current methods require the presence of the electric drive unit to measure operating parameters like energy consumption of air conditioning devices in vehicles, making it impractical to prove compliance with energy consumption values without the unit installed.
Innovation Solution
A simulation device calculates and simulates the return temperature and volume flow of the refrigerant, mimicking the electric drive unit's operation to determine operating parameters, allowing for the use of waste heat without the actual unit present, using a one-dimensional simulation model and controlling the refrigerant circuit to replicate the electric drive unit's behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If measurements are performed only when the vehicle is fully equipped with the electric drive unit, then reliable measurements of energy consumption can be obtained, but the complexity and cost of the testing setup increases significantly
Solution Approach 1:
The patent applies the copying principle by creating a simulation model that replicates the electric drive unit's behavior, including its thermal characteristics and waste heat generation. This virtual copy allows measurements to be performed without the physical drive unit being present, thereby reducing testing complexity while maintaining measurement reliability. The simulation model is integrated into the test bench to generate realistic operating conditions and parameters.
2Measurement precision
If the electric drive unit is installed in the vehicle to perform measurements, then accurate energy consumption data can be collected, but the ability to perform preliminary testing and compliance verification is lost
Solution Approach 1:
The patent implements preliminary action by enabling energy consumption measurements to be performed before the electric drive unit is actually installed in the vehicle. The simulation model allows the test bench to predict and measure energy consumption characteristics in advance, facilitating preliminary testing and compliance verification. This approach provides flexibility in testing schedules and allows multiple test scenarios to be evaluated before final vehicle assembly.
3Use of energy by moving object
If waste heat from the electric drive unit is utilized to improve air conditioning energy efficiency, then the overall energy consumption decreases, but the system complexity increases due to additional heat exchanger components
Solution Approach 1:
The patent applies the universality principle by designing the heat exchanger to serve multiple functions simultaneously. The same heat exchanger component is used both for thermal management of the electric drive unit (cooling) and for providing heat to the air conditioning system (heating). This multi-functionality allows waste heat utilization without requiring separate dedicated components, thereby limiting the increase in system complexity while achieving improved energy efficiency.
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
Enables the determination of energy consumption and efficient use of waste heat for air conditioning, allowing for compliance verification without the electric drive unit, with the simulation device accurately representing various operating conditions and influencing factors like route topography and occupancy levels.
Implementation Method 1
imposing the return temperature calculated in step a) on the refrigerant by controlling a heating/cooling device of the refrigerant circuit
Implementation Method 2
impressing the return volume flow calculated in step a) on the refrigerant by controlling a pump of the refrigerant circuit
Implementation Method 3
the air conditioning unit is connected to a heat exchanger, which is put into operation when additional heat is required and through which a cooling medium for the electric drive unit flows. At the heat exchanger, waste heat from the cooling circuit for the electric drive unit is transferred to a coolant in a cooling circuit of the air conditioning unit
Data Source
Figure 1~2
AI summary
A method and a device for determining at least one operating parameter of an air conditioning unit (1) used for air conditioning the interior of a vehicle, which is connected to a heat exchanger (9) for the purpose of utilizing waste heat from a refrigerant circuit (3) of an electric drive unit (2), the heat exchanger being supplied with a refrigerant depending on the current heating demand of the air conditioning unit (1), which is intended to transfer waste heat from the electric drive unit to the air conditioning unit (1) via the heat exchanger (9), characterized by the steps a) calculating a return temperature (TR) and a return volume flow rate (SR) for the refrigerant using a simulation device (2S) based on a simulation model that, starting from current operating conditions of the electric drive unit,a) simulates a load and inertia of the electric drive unit as well as the control of the operation of the electric drive component, b) applies the return temperature (TR) calculated in step a) to the refrigerant by controlling a heating/cooling device of the refrigerant circuit (3) and applies the return volume flow rate (SR) calculated in step a) to the refrigerant by controlling a pump (4, 13) of the refrigerant circuit (3), and c) acquires measured values for the operating parameter.