Vehicle HVAC Heating Power Control Using Existing Sensors
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Solution Overview
Problem
Current air conditioning systems for vehicles require additional sensors to control heating power, which increases complexity and cost, whereas the existing pressure and temperature sensors used in 'air conditioning' mode are not sufficient for effective control in 'heating' mode.
Innovation Solution
A method that utilizes the existing pressure and temperature sensors to estimate the heating power of the thermodynamic loop by applying power balance equations and saturation temperature data, allowing for regulation of the heating power without additional sensors, by considering the air flow temperature before and after passing through the evaporator and auxiliary condenser.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If additional sensors are installed to control heating power in heating mode, then temperature control precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent makes existing sensors serve dual functions: the pressure sensor at the condenser outlet and the temperature sensor at the evaporator outlet are used for both air conditioning mode control and heating mode control. Through mathematical modeling and parameter calculation, these sensors provide sufficient data to control heating power without requiring dedicated heating mode sensors, thus avoiding additional hardware while maintaining control precision.
Solution Approach 2:
The system uses its own existing measurement infrastructure (pressure and temperature sensors already installed for AC mode) to self-sufficiently control heating mode operation. By calculating heating power requirements through thermodynamic relationships and using available sensor data, the system eliminates the need for external or additional measurement devices.
2Measurement precision
If additional sensors are installed to control heating power, then heating power control accuracy is improved, but manufacturing cost increases
Solution Approach 1:
Existing sensors are made multi-functional to reduce manufacturing costs. The pressure sensor and temperature sensor originally designed for air conditioning mode control are utilized for heating mode control as well, eliminating the need to purchase and install additional sensors specifically for heating function.
Solution Approach 2:
The patent changes the operational parameters and control strategy rather than adding hardware. By modifying how existing sensor data is processed and used through mathematical models and control algorithms, the system achieves accurate heating power control without the expense of additional sensors.
3Device complexity
If existing sensors are used for heating mode control, then device complexity is reduced, but measurement precision for heating control deteriorates
Solution Approach 1:
The patent introduces mathematical models and calculation algorithms as intermediaries between the existing sensors and the heating control system. These models transform the raw sensor data (pressure at condenser outlet, temperature at evaporator outlet) into accurate heating power control signals through thermodynamic relationships, maintaining precision without additional hardware.
Solution Approach 2:
The system changes the control parameters and control strategy to adapt existing sensors for heating mode. By using calculated parameters derived from thermodynamic equations rather than direct measurements, the system maintains control precision while avoiding additional sensors.
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 efficient control of heating power in air conditioning systems using existing sensors, simplifying the electrical architecture and reducing the need for additional hardware, while maintaining effective temperature regulation in both 'air conditioning' and 'heating' modes.
Implementation Method 1
a pressure sensor placed at the condenser outlet, to measure the high pressure value in the thermodynamic loop
Implementation Method 2
a temperature sensor, to measure the temperature of the airflow after passing through the evaporator
Implementation Method 3
an auxiliary condenser and/or a heat exchange radiator, the evaporator, on the one hand, and the auxiliary condenser and/or the heat exchange radiator, on the other hand, being placed in a air circulation duct for an air flow capable of being heated
Data Source
Figure 1~2
Figure 3a~4
Figure 5~6
AI summary
The method involves measuring a pressure (Pd) at an outlet of a compressor, and measuring a temperature (Tev) of air flow, infront or behind an evaporator (12). The temperature of air flow, infront or behind the evaporator is estimated. The temperature of air flow at an outlet of an air circulation duct (20) is estimated from the measured pressure and the temperature. The temperature of air flow heated by auxiliary conditioner (11) and/or heat exchange radiator is adjusted based on set point of the temperature of air conditioned air flow at the outlet of the duct.